Latest ArticlesRapid detection and identification of Escherichia coli (E. coli) is essential to prevent its quickly spread. In this study, a novel fluorescence probe based on ZnTe quantum dots (QDs) modified by mannose (MAN) had been prepared for the determination of E. coli. The results showed that the obtained QDs showed excellent selectivity toward E. coli, and presented a good linearity in range of 1.0×105~1.0×108 CFU/mL. The optimum fluorescence intensity for detecting E. coli was found to be at pH 7.0 with a temperature of 25 ℃ and incubation time of 20 min. Under these optimum conditions, the detection limit of E. coli was 4.6×104 CFU/mL. The quenching was discussed to be a static quenching procedure, which was proved by the quenching efficiency of QDs decreased with the temperature increasing.
Chlorinated organic pollutants (COPs) have caused serious contaminants in soil and groundwater, hence developing methods to remove these pollutants is necessary and urgent. By a simple hydrothermal method, we synthesized the bimetallic iron-nickel sulfide (FeNiS) particles which exhibited excellent catalytic property of COPs removal. FeNiS was chosen as the peroxydisulfate (PDS) activator to removal COPs including 4-chlorophenol (4-CP), 1, 4-dichlorophenol (1, 4-DCP) and 2, 4, 6-trichlorophenol (2, 4, 6-TCP). The results show that FeNiS can efficiently activate PDS to produce sulfate radical (SO4·-) which plays major role in the oxidative dechlorination and degradation due to its strong oxidizing property and the ability of producing hydroxyl radicals (·OH) in the alkaline condition. Meanwhile, the Cl- abscised from COPs during the dechlorination can turn into the chlorine radicals and enhance the degradation and cause further mineralization of intermediate products. This bimetallic FeNiS catalyst is a promising PDS activator for removal of chlorinated organics.
As one of the most environmentally friendly photovoltaic (PV) conversion equipments, aqueousprocessed CdTe nanocrystal solar cells (NC SCs) have attracted great interest in recent years because of their excellent properties such as high charge-carrier mobility and broad absorption. However, two issues including interfacial recombination and leakage current seriously restrict their performance. In this paper, insulating polymer poly(vinyl pyrrolidone) (PVP) is introduced into CdTe NC SCs to solve the problems. The experimental results of transmission electron microscopy (TEM), atomic force microscopy (AFM) and dark current measurements, etc., demonstrate the leakage current is effectively suppressed by introducing PVP. Through further designing device structure, the reduction of interfacial recombination after introducing PVP is confirmed. By strategically taking the advantages of PVP properties (e.g., water solubility and thermostability), the power conversion efficiency of the devices with PVP is enhanced by almost 37% compared to pure CdTe devices. This work demonstrates an effective and low-cost method to fabricate NC SCs via aqueous route. Moreover, it also proves that appropriate content of insulating polymer is of beneficial in promoting the PV performance.
The 1, 3-dipolar cycloaddition reaction of dimethyl hex-2-en-4-ynedioate with azomethine ylides derived from reaction of L-proline with various isatins in methanol selectively resulted in the formation of functionalized spiro[indoline-3, 3'-pyrrolizine]acrylates as main products and spiro[indoline-3, 3'-pyrrolizine]propiolates as minor products. This result indicated that the electron-deficient alkyne has higher reactivity than that of electron-deficient alkene in 1, 3-dipolar cycloaddition reaction.
As a daily food for billions of people for thousands of years, whole grain is rich in phenolic compounds and may have huge potentials to provide natural antioxidants. Herein, owing to the significant biomedical potential, the effect of whole wheat flour solution as antioxidant wound coating for enhanced wound healing has been studied. The results show that the low concentration of whole wheat flour solutions have good biocompatibility and can scavenge radical and intracellular ROS in vitro, accelerating tissue remodeling in vivo to promote wound healing. This kind of whole wheat flour solution has great potential application for cutaneous wound repair.
Herein, we report the first RhIII-catalyzed regioselective C8 arylation of quinoline N-oxides with commercially available arylboronic acids as coupling partners. This procedure is simple, and the reaction shows perfect regioselectivity, a broad substrate scope, and isolated yields of up to 92%. We demonstrate the utility of the reaction by using it for late-stage functionalization of a fungicide.
The physicochemical properties of surfaces have a great effect on the micro-morphologies of the crystal structures which are in contact with them. Understanding the interaction mechanism between the internal driving forces of the crystal and external inducing forces of the surfaces is the prerequisite of controlling and obtaining the desirable morphologies. In this work, the dynamic density functional theory was applied to construct the free energy functional expression of polyethylene (PE) lattice, and the micro-dynamic evolution processes of PE lattice morphology near the surfaces with different properties were observed to reveal the interaction mechanism at atomic scale. The results showed that the physical and chemical properties of the external surfaces synergistically affect the morphologies in both the defect shapes and the distribution of the defect regions. In the absence of the contact surfaces, driven by the oriented interactions among different CH2 groups, PE lattices gradually grow and form a defect-free structure. Conversely, the presence of contact surfaces leads to lattice defects in the interfacial regions, and PE lattice shows different self-healing abilities around different surfaces.
Reusable palladium nanoparticles highly dispersed in porous and hydrophilic interpenetrating polymer networks (IPN), i.e., Pd@IPN hybrid gels, are employed for catalysis of Suzuki and Heck coupling reactions. Good yields are obtained with high turnover frequencies when the reactions are run with very low Pdloadings. The use of IPN gives better recyclability than that of crosslinked polyvinyl alcohol alone. The polymer networks allow the reactants to have easy access to the Pd metals. The catalysts combine high activity with the reusability offered by the heterogeneous system, without the need for strong coordination or chelating ligands.
Transmembrane anion transporters have attracted significant attention as therapeutic agents because of their potential to disrupt cellular ion homeostasis, in which, most of the synthetic anionic transporters are organic small molecules whose synthesis routes are usually complex and tedious, and the related biological research is also only in infancy. Hence, we synthesized a kind of chloride anion (Cl-) and sodium cation (Na+) nanocarrier based on poly(D, L-lactic-co-glycolic acid) (PLGA) which was coated with polydopamine (PDA) to provide target release factor. When the nanocarrier arrives in acidic environment such as lysosomes through endocytosis, Cl- and Na+ will be released fast from the nanocarrier resulting in imbalance of cell homeostasis for inducing apoptosis. Cell experiments show that the nanocarrier promotes apoptosis and leads to an increased concentration of reactive oxygen species. By exploring the concentration of cytochrome c in mitochondria and cytoplasm and the activities of key enzymes caspase-9 and caspase-3 in apoptosis process, it is proved that the apoptotic pathway is caspase-dependent. This novel strategy allows the research of anion transporter no longer limited to artificial synthesis of small molecular and provides a novel and effective direction to investigate ion homeostasis, ion transport and cancer treatment.
Peony pollen is a cheap and readily available biomass material with a relatively high protein content. In this work, it was employed as an N-rich precursor to prepare the nitrogen-doped porous carbon for supercapacitor application. The porous carbon microspheres were prepared through a hydrothermal method and subsequent carbonization process. Notably, ammonium borofruoride and potassium hydroxide were employed respectively as an etchant and an activator to modify the porosity of the materials. The as prepared ANPPCs-700 has a super high BET specific surface area of 824.69 m2/g. The microstructure, chemical state and electrochemical properties of the product were investigated in detail. The prepared nitrogen-doped carbon microspheres exhibits excellent specific capacity of 209 F/g at a current density of 1 A/g and remained 92.5% of the initial capacitance after 5000 deep cycles at 5 A/g.
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