Quantitative Screening of Cell‐Surface Gangliosides by Nondestructive Extraction and Hydrophobic Collection

A screening strategy involving designed extractors and collectors was used for the nondestructive quantitation of gangliosides on cell surfaces. The extractors were constructed by functionalizing maleimide silica bubbles with a DNA probe, which contains an endonuclease cleavage site and a boronic acid end to extract cell‐surface sialic acid‐containing compounds through simple centrifugation. After the extractors containing the extracted compounds were incubated with endonuclease, the released oligonucleotide‐gangliosides were selectively collected by silanized collector bubbles through hydrophobic interactions. The in vitro fluorescent signals from the collectors were used for the quantitation of cell‐surface gangliosides. By combining with sialidase cleavage, a protocol for the identification of ganglioside subtypes was developed. The successful monitoring of the regeneration of cell‐surface gangliosides demonstrates the potential of this strategy in probing related biological processes.     

Simple and sensitive determination of arsenic by volatile arsenic trichloride generation atomic fluorescence spectrometry

A simple, sensitive and interference-free method was proposed for the determination of arsenic, based on the generation of volatile arsenic trichloride coupled with atomic fluorescence spectrometry. Thiourea, together with l-ascorbic acid, was used to reduce As(V) to As(III), and the chloride generation was based on the reaction between As(III) and hydrochloric acid. Under the optimized experimental conditions, the present procedure allows for the quantification of arsenic in the concentration range of 0.01–4.0 mg L⁻¹, with a limit of detection (3σ) of 6.0 μg L⁻¹. The relative standard deviation (R.S.D.) is 4.0% for 0.1 mg L⁻¹ arsenic (n = 7). Finally, the proposed method was successfully applied to the determination of arsenic in several certified reference samples (stainless steel, alloy steel, copper alloy and water sample) and real samples (brass material and spiked cobalt material), with analytical results well-agreed with those by ICP-MS.     

Hierarchical porous aero-cryogels for wind energy enhanced solar vapor generation

An integrated aero-cryogel (A-CG) monolith with hierarchical porous structure was developed by inter-crosslinking of cellulose nanofiber/polylactic acid nanocomposite aerogel and carboxymethyl cellulose (CMC) cryogel (CG). The photothermal nanoparticles-enriched CMC CG phase served as a sunlight absorbing layer, exhibiting a broadband sunlight absorption of 98%. Due to the large amount of weakly bounded water molecules, the swelled CMC CG possessed a lower evaporation enthalpy than that of pure water, which facilitates water evaporation, while the nanocomposite aerogel phase acted as an excellent thermal insulator and afforded highly efficient water transport channels. Thus, the developed A-CG monolith supported by insulated polystyrene foam to protrude above the water surface, could reach an evaporation rate of 2.16 kg m^?2 h^?1 under an irradiation of 1 Sun (100 mw/cm²) with an efficiency of 93.6%. More remarkably, when the wind energy was imparted, an evaporation rate of 5.67 kg m^?2 h^?1 was achieved at a wind speed of 3 m s^?1. The high-efficiency purification outcomes of various raw water demonstrate the great potentials of A-CG material in solar vapor generation.

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Light-responsive nanocomposites combining graphene oxide with POSS based on host-guest chemistry

A facile methodology has been proposed to construct lightresponsive nanocomposites composed of GO and POSS based on host-guest inclusion of CD/Azo. Through manipulating photo-irradiation conditions, GO and POSS moieties in GO-POSS exhibited impressive and reversible supramolecular assembly/disassembly behaviors and had remarkable effect on oxygen barrier property of PVA-coated films, which would have potential application for smart gas barrier materials in packaging.     

Copper-catalyzed C–N coupling/C–H functionalization: A tandem approach to azole-fused quinazoline derivatives

A Cu-catalyzed tandem synthesis of azole-fused pyrimido[1,2-c]quinazolines and imidazo[1,2-c]quinazolines has been developed. The reaction is based on a C–N cross-coupling/C–H functionalization reaction of 2-(2-bromophenyl)-1,4,5,6-tetrahydropyrimidines with azoles. A variety of the desired polycyclic products were obtained in moderate to excellent yields.     

Photocatalytic degradation of C.I. Acid Blue 80 in aqueous suspensions of titanium dioxide under sunlight

The dye C.I. Acid Blue 80 (AB80) was easily degraded by TiO₂-P25 assisted photocatalysis in aqueous dispersion under irradiation of sunlight. The optimal reaction conditions were [TiO₂] = 2.0 g/L, pH = 10, [H₂O₂] = 5 mmol/L. The photocatalytic reaction followed pseudo-first order kinetics. The adsorption of AB80 onto TiO₂ was in accord with Langmuir equation.     

常压下酸催化菊糖水解反应动力学研究

研究了菊芋中菊糖的酸催化水解。通过改变常压下菊糖酸催化水解的反应条件研究了反应动力学 ,得出该反应符合一级串连反应规律的结论     

Preparation of activated carbon from polyaniline by zinc chloride activation as supercapacitor electrodes

Activated carbon for supercapacitor electrode was prepared from polyaniline using chemical activation with ZnCl₂. The morphology, surface chemical composition, and surface area of the as-prepared carbon materials were investigated by scanning electron microscope, atomic force microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurement, respectively. Electrochemical characteristics were evaluated by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy tests in 6.0 mol L⁻¹ KOH aqueous solution. The electrochemical measurements showed that ZnCl₂ activation led to better capacitive performances. The activated carbon presented a high-specific gravimetric capacitance of 174 F g⁻¹, with rectangular cyclic voltammetry curves at a scan rate of 2 mV s⁻¹, and it remained 93% even at a high scan rate of 50 mV s⁻¹. These demonstrated that activated carbon would be a promising electrode material for supercapacitors.

     

Acyclic Janus‐AT Nucleoside Host Channels Precisely Lock Water into Single‐File Wires with Local Rotational Flexibility

Confining polar water molecules to particular geometries demands sophisticated intermolecular interactions, and not many small synthetic molecules have accomplished such a task. Herein, regioisomeric acyclic Janus‐AT nucleosides ( 1 and 2 ), with a self‐complementary fused genetic alphabet and conformationally flexible side chains, have been selectively synthesized. 1 and 2 adopt disparate base‐pair motifs from the π–π stacked hydrophobic base moieties and distinct hydrogen bond (HB) interconnections from the hydrophilic sugar residues, which in turn lead to divergent, intricate intermolecular interaction networks with different capacities to confine water molecules. Under the precise control of the host framework of the N⁸‐regioisomer, separate ordered single‐file water wires can be locked through special three‐HB clamps into unique inter‐ and intra‐wire geometrical alignments. Localized dynamic synchronized rotations within the fixed framework coordinated by both the host hydroxy groups and guest water molecules were observed in a temperature‐induced reversible single‐crystal‐to‐single‐crystal transition (SCSCT).     

Metal nanoparticles with clean surface: The importance and progress

Metal nanoparticles (MNPs) with regular shapes could significantly improve their electrocatalytic performance for many reactions and build an important platform for precise understanding of the relationship between the structure and activity. For the synthesis of MNPs through a wet chemical method, the capping agents introduced during the process of synthesis are usually strongly adsorbed on the surface of the nanoparticles, occupying the active sites of the catalyst, thus hindering their catalytic performance. However, to correctly understand the correlation between the surface structure of nanoparticles and electrochemical performance, it is necessary to guarantee nanoparticles with clean surfaces as a model catalyst. Therefore, obtaining MNPs with clean surfaces is essential. Herein, we summarized the representative developments in obtaining MNPs with clean surface. Because nanoparticles with clean surfaces make it possible to understand the real relationship between structure and activity without the interference of surfactants at nanoscale, it could make a bridge between the fundamental research from single-crystal study and industrial application.