A sensitive and label-free impedimetric biosensor based on an adjunct probe

A highly sensitive and label-free impedimetric biosensor is achieved based on an adjunct probe attached nearby the capture probe. In this work, the adjunct probe was co-assembled on the surface of gold electrode with the capture probe hybridized with the reporter probe, and then 6-mercapto-1-hexanol was employed to block the nonspecific binding sites. When target DNA was added, the adjunct probe functioned as a fixer to immobilize the element of reporter probe displaced by the target DNA sequences and made the reporter probe approach the electrode surface, leading to effective inhibition of charge transfer. The increase in charge transfer resistance is related to the quantity of the target DNA in a wide range. The linear range for target DNA with specific sequences was from 0.1 nM to 0.5 μM with a good linearity (R = 0.9988) and a low detection limit of 6.3 pM. This impedimetric biosensor has the advantages of simplicity, sensitivity, good selectivity, and large dynamic range.     

Preparation of NdCrO3 nanoparticles and their catalytic activity in the thermal decomposition of ammonium perchlorate by DSC/TG-MS

Orthorhombic structural perovskite NdCrO₃ nanocrystals with size of 60 nm were prepared by microemulsion method, and characterized by XRD, TEM, HRTEM, SEM, EDS and BET. The catalytic effect of the NdCrO₃ for thermal decomposition of ammonium perchlorate (AP) was investigated by DSC and TG-MS. The results revealed that the NdCrO₃ nanoparticles had effective catalysis on the thermal decomposition of AP. Adding 2% of NdCrO₃ nanoparticles to AP decreased the temperature of thermal decomposition by 87° and increased the heat of decomposition from 590 to 1073 J g⁻¹. Gaseous products of thermal decomposition of AP were NH₃, H₂O, O₂, HCl, N₂O, NO, NO₂ and Cl₂. The mechanism of catalytic action was based on the presence of superoxide ion O₂ ⁻ on the surface of NdCrO₃, and the difference of thermal decomposition of AP with 2% of NdCrO₃ and pure AP was mainly caused by the different extent of oxidation of ammonium.     

二元域上线性群的纯数量刻画

本文给出了仅用元的阶之集对二元域上小阶线性群及其自同构群的刻画.指出并纠正了文[5]中的错误.     

PREPARATION OF STAR NETWORK PEG-BASED GEL POLYMER ELECTROLYTES FOR ELECTROCHROMIC DEVICES

An amorphous,colorless,and highly transparent star network polymer with a pentaerythritol core linking four PEG-block polymeric arms was synthesized from the poly(ethylene glycol)(PEG),pentaerythritol,and dichloromethane by Williamson reaction.FTIR and ~1H-NMR measurement demonstrated that the polymer repeating units were C[CH_2-OCH_2O-(CH_2CH_2O)_m-CH_2O-(CH_2CH_2O)_n-CH_2O]_4.The polymer host held well mechanical properties for pentaerythritol cross-linking.The gel polymer electrolytes based on Lithium...     

The sulphate radical is not involved in aqueous radiation oxidation processes

The H₂O₂/persulphate systems are of enormous environmental and commercial importance with the sulphate radical (SO₄⁻) being assumed as the oxidizing/bleaching species. We show that under normal conditions (air-saturated) no SO₄⁻ is produced and, most likely, a much longer-lived species, the adduct of O₂ and the persulphate radical, is formed.     

Neglschisandrins A-B: two new dibenzocyclooctene lignans from Schisandra neglecta

Two new dibenzocyclooctene lignans, neglschisandrins A-B (1-2), were isolated from the stems of Schisandra neglecta. Their structures and stereochemistries were elucidated by spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MS techniques.     

Base-free selective oxidation of monosaccharide into sugar acid by surface-functionalized carbon nanotube composites

Selective oxidation of biomass-derived monosaccharide into high value-added chemicals is highly desirable from sustainability perspectives. Herein, we demonstrate a surface-functionalized carbon nanotube-supported gold (Au/CNT-O and Au/CNT-N) catalyst for base-free oxidation of monosaccharide into sugar acid. Au/CNT-O and Au/CNT-N surfaces successfully introduced oxygen- and nitrogen-containing functional groups, respectively. The highest yields of gluconic acid and xylonic acid were 93.3% and 94.3%, respectively, using Au/CNT-N at 90 °C for 240 min, which is higher than that of using Au/CNT-O. The rate constants for monosaccharide decomposition and sugar acid formation in Au/CNT-N system were higher, while the corresponding activation energy was lower than in Au/CNT-O system. DFT calculation revealed that the mechanism of glucose oxidation to gluconic acid involves the adsorption and activation of O₂, adsorption of glucose, dissociation of the formyl C-H bond and formation of O-H bond, and formation and desorption of gluconic acid. The activation energy barrier for the glucose oxidation over Au/CNT-N is lower than that of Au/CNT-O. The nitrogen-containing functional groups are more beneficial for accelerating monosaccharide oxidation and enhancing sugar acid selectivity than oxygen-containing functional groups. This work presents a useful guidance for designing and developing highly active catalysts for producing high-value-added chemicals from biomass.     

Black phosphorus nanosheets-based tumor microenvironment responsive multifunctional nanosystem for highly efficient photo-/sono-synergistic therapy of non-Hodgkin lymphoma

Finding improved therapeutic protocols against non-Hodgkin's lymphoma (NHL) remains an unmet clinical demand. Phototherapy is a promising alternative treatment for traditional clinical therapeutic methods, but the limited tissue penetration blocks the therapeutics. Inspired by the excellent physical and chemical properties of black phosphorus nanosheets (BPNSs), a fluorescence and thermal imaging guided photo-/sono-synergistic treatment platform BPNSs@PEG-SS-IR780/RGD is developed. This ingenious multifunctional theranostic platform not only exhibits outstanding photothermal conversion efficiency and highly efficient reactive oxygen species generation, but also has good biocompatibility, tumor-targeting and tumor microenvironment responsiveness. In addition, BPNSs@PEG-SS-IR780/RGD could actively target the tumor sites and generate excellent photothermal, photodynamic and sonodynamic therapeutic efficacy. Both in vitro and in vivo experiments indicate that BPNSs@PEG-SS-IR780/RGD can be a promising nanomaterial for NHL imaging and therapy. Taken together, this study not only expands the application field of black phosphorus materials, but also provides a possibility to design a new generation of NHL treatment regimens with clinical application potential.     

An Electrochemical Sensing Strategy for Amantadine Detection Based on Competitive Host‐guest Interaction of Methylene Blue/β‐cyclodextrin/Poly(N‐acetylaniline) Modified Electrode

A novel electrochemical strategy for the detection of amantadine (AMD) has been developed based on the competitive host‐guest interaction of AMD and methylene blue (MB) with β‐cyclodextrin (β‐CD). Due to the host‐guest interaction, MB molecules can enter into the hydrophobic inner cavity of β‐CD, and the MB/β‐CD/poly(N‐acetylaniline)/glassy carbon electrode displays a remarkable reduction peak due to MB. In the presence of AMD, competitive association to β‐CD occurs and the MB molecules are displaced by AMD, resulting in a decrease of reduction peak current of MB. The difference value of the cathodic peak current showed a linear relationship with the AMD concentration.     

Nanostructured spinel-type M(M = Mg,Co, Zn)Cr2O4 oxides: novel adsorbents for aqueous Congo red removal

Nanostructured spinel-type M(M = Mg, Co, Zn)Cr₂O₄ oxides with novel adsorbents for aqueous Congo red removal were synthesized by a polyacrylamide gel method and studied for their phase structure, microstructure, adsorption performance, and multiferroic behavior. The phase structure and purity analysis revealed that the nanostructured spinel-type M(M = Mg, Co, Zn)Cr₂O₄ oxides presented a spinel-type cubic structure, and the formation of a secondary phase such as Cr₂O₃, MgO, ZnO, or Co₃O₄ was not observed. The microstructure characterization confirmed that the spinel-type MCr₂O₄ oxides grew from fine spherical particles to large rhomboid particles. Adsorption experiments of spinel-type MCr₂O₄ oxides for adsorption of Congo red dye were fitted well with the pseudo-second-order kinetics. The adsorption capacity of the ZnCr₂O₄ oxide (44.038 mg/g, pH 7, temperature 28 °C, initial dye concentration 30 mg/L) was found to be higher than that of MgCr₂O₄ oxide (43.592 mg/g, pH 7, temperature 28 °C) and CoCr₂O₄ oxide (28.718 mg/g, pH 7, temperature 28 °C). The effects of initial adsorbent concentration, initial dye concentration, pH, and temperature between the ZnCr₂O₄ oxide and Congo red dye at which optimal removal occurs, were performed. The thermodynamic studies confirmed that a high temperature favors the adsorption of Congo red dye onto ZnCr₂O₄ oxide studied. The nanostructured spinel-type M(M = Mg, Co, Zn)Cr₂O₄ oxides that exhibited high adsorption performance for adsorption of Congo red dye can be ascribed to the synergistic effect of electrostatic interaction, pore filling, and ion exchange. The present work suggested that the nanostructured spinel-type M(M = Mg, Co, Zn)Cr₂O₄ oxides have excellent adsorption performance and multiferroic behavior, which shows potential applications for removal of the Congo red dye from wastewater, magnetic memory recording media, magnetic sensor, energy collection and conversion device, and read/write memory.