Imaging the oxygen wave with a single bioluminescent bacterium

We developed a capability of a monolayer of bioluminescent (BL) bacteria for spatiotemporally visualizing the heterogeneous distribution and dynamic evolution of interfacial oxygen concentration, resulting in the discovery of spontaneous and stochastic oxygen waves at the interface between the substrate and an undisturbed, apparently still solution. Wild type bacteria, P. phosphoreum, spontaneously emit light during the native metabolism processes, i.e., bioluminescence. The emission intensity is sensitively regulated by oxygen concentration. By taking the electrolysis of water as a model, it was demonstrated that time-lapsed BL imaging of a bacterial monolayer allowed for visualizing the dynamic distribution of oxygen. The results were quantitatively understood with a physical model involving the diffusion equation and Michaelis–Menten equation. Unexpectedly, further study uncovered a spontaneous and stochastic oxygen wave in a standard well of a microtiter plate, which was subsequently attributed to the inevitable micro-convections induced by inhomogeneous evaporation and thermal fluctuation. Because of the wide application of microtiter plates, this study sheds new light to better understand the apparent heterogeneity in cell-culture and bio-assays.

We developed a capability of a monolayer of bioluminescent (BL) bacteria for spatiotemporally visualizing the heterogeneous distribution of interfacial oxygen concentration, resulting in the discovery of spontaneous and stochastic oxygen waves.     

分析化学在线课堂引入实验视频教学模式改革

The current situation of analytical chemistry teaching and reform, as well as some problems in micro-videos of online classroom was analyzed. In order to solve these problems, short experimental videos were introduced to the online classroom to demonstrate experimental methods. The new teaching mode achieves mutual integration and promotion of the classroom teaching and laboratory teaching, providing opportunities and challenges for the teaching reform of chemistry online course. The results of the teaching reform were investigated and analyzed by questionnaire.     

Autologous Cobalt Phosphates with Modulated Coordination Sites for Electrocatalytic Water Oxidation

The correlation between metal coordination and electrocatalytic water oxidation performance is elusive in many cobalt‐based materials. Herein, we designed an ideal Co phosphate‐based platform to explore the effect of coordination environment on oxygen evolution reaction (OER) activity. The cobalt geometry was modulated from octahedral to tetrahedral by simple removal of water ligands in Co₃(PO₄)₂?8 H₂O. Other features except the coordination structure in the two autologous materials remain similar. The two analogues display the same OER kinetics, but the anhydrous Co₃(PO₄)₂ exhibits a greatly enhanced OER activity. On the basis of Raman and operando XAS results, the higher intrinsic activity of the Co tetrahedral sites is because they facilitate the formation of active high valent cobalt (hydr)oxide intermediates during OER. This work not only brings insights of OER on Co‐based electrocatalysts but also provides a reference system to study the effect of metal geometry on electrocatalysis.     

Enhanced electrochemiluminescence employed for the selective detection of methyl parathion based on a zirconia nanoparticle film modified electrode

A simple, rapid and sensitive electrochemiluminescence (ECL) sensor was proposed for direct measurements of methyl parathion (MP) based on the strong affinity of a nano zirconia particles (ZrO(2) NPs) modified film on the electrode to the phosphoric group. ZrO(2) NPs, which could provide a larger absorption area to immobilize organophosphorus, was firstly modified on the glassy carbon electrode surface to prepare the proposed ECL sensor (ZrO(2)/GC). Subsequently, the ZrO(2)/GC electrode was scanned from -0.8 to +0.6 V to obtain the background signal at 0.44 V in a luminol/KCl solution. Then, a certain concentration of MP was added to an aqueous solution for 240 s, which was absorbed onto the ZrO(2)/GC electrode surface. Moreover, the MP absorbed on the surface of the ZrO(2)/GC electrode enhanced the ECL signal of luminol in the luminol/KCl solution, which increased with the concentration of MP. As a result, a novel ECL sensor was obtained in a luminol/KCl solution. The MP was determined in the range of from 3.8 × 10(-11) to 3.8 × 10(-6) mol L(-1), with a low detection limit of 1.27 × 10(-11) mol L(-1) (S/N = 3). The proposed ECL sensor performance for MP detection will open a new field in the application of rapid and screen detection of ultra-trace amounts of organ phosphorus pesticides (OPs) of vegetables used in farm markets.     

Novel method for the rapid and specific extraction of multiple β2‐agonist residues in food by tailor‐made Monolith‐MIPs extraction disks and detection by gas chromatography with mass spectrometry

A quick and specific pretreatment method based on a series of extraction clean‐up disks, consisting of molecularly imprinted polymer monoliths and C₁₈ adsorbent, was developed for the specific enrichment of salbutamol and clenbuterol residues in food. The molecularly imprinted monolithic polymer disk was synthesized using salbutamol as a template through a one‐step synthesis process. It can simultaneously and specifically recognize salbutamol and clenbuterol. The monolithic polymer disk and series of C₁₈ disks were assembled with a syringe to form a set of tailor‐made devices for the extraction of target molecules. In a single run, salbutamol and clenbuterol can be specifically extracted, cleaned, and eluted by methanol/acetic acid/H₂O. The target molecules, after a silylation derivatization reaction were detected by gas chromatography‐mass spectrometry. The parameters including solvent desorption, sample pH, and the cycles of reloading were investigated and discussed. Under the optimized extraction and clean‐up conditions, the limits of detection and quantitation were determined as 0.018–0.022 and 0.042–0.049 ng/g for salbutamol and clenbuterol, respectively. The assay described was convenient, rapid, and specific; thereby potentially efficient in the high‐throughput analysis of β₂‐agonists residues in real food samples.     

Studies on the Aero-optical Phenomena of Free-vortex Aerodynamic Window′s Jet

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｏａｔｔａｉｎｈｉｇｈ ｐｏｗｅｒｏｕｔｐｕｔｏｆｔｈｅｇａｓｄｙｎａｍｉｃｌａｓｅｒｃｈｅｍｉｃａｌｌａｓｅｒ ,ｈｉｇｈ ｓｐｅｅｄｇａｓｆｌｏｗｔｏｒｅｍｏｖｅｗａｓｔｅｈｅａｔｉｓｒｅｑｕｉｒｅｄ .ＥｓｐｅｃｉａｌｌｙａｔａｎａｖｅｒａｇｅｐｏｗｅｒｌｅｖｅｌｌａｒｇｅｒｔｈａｎｔｅｎｓｏｆｋＷ ,ｏｎｌｙｈｉｇｈｓｐｅｅｄｇａｓｆｌｏｗｃａｎｅｎｓｕｒｅｅｆｆｉｃｉｅｎｔｈｅａｔｅｌｉｍｉｎａｔｉｏｎ .Ｔｈｅｒｅｆｏｒｅｔｈｅｌａｓｅｒｇａｓｍｅｄｉｕｍｏｆ…     

Controlling magnetic dipole transition with magnetic plasmonic structures

A plasmonic structure with double gold patches is proposed for enhancing the spontaneous emission of a magnetic dipole transition through a magnetic hot area. A Purcell factor of nearly 2000 can be obtained at optical frequencies together with a low sensitivity in spatial and spectral mismatches between the light emitter and the resonance mode. The associated resonance can be tuned from the visible to the IR frequencies, enabling efficient control of forbidden transitions using plasmonic structures.     

Synthesis and Bioactivities of Clopyralid Hydrazide-Hydrazones

A series of clopyralid hydrazide-hydrazone derivatives (4a–p) have been synthesized. Their structures were confirmed by elemental analysis, infrared, and ¹H NMR spectra. The bioactivities of compounds 4a–p were tested with barnyard grass, rape, and S. aureus, but the results showed that they could not be considered the promising herbicidal or antibacterial agents.     

Efficient Protocol for the Synthesis of Novel Spiro[acenaphthylene-1,2′-pyrrolidin]-2-one Compounds

An efficient catalyst-free synthesis of 3′-benzoyl-4′,5′-diphenyl-2H-spiro[acenaphthylene-1,2′-pyrrolidin]-2-one derivatives via one-pot 1,3-dipolar cycloaddition of acenaphthenequinone, arylmethyl amines, and chalcones with high regioselectivity is described. The structure of the cycloadducts were characterized by infrared, high-resolution mass spectrometry (electrospray ionization), ¹H NMR, and ¹³C NMR spectra, and the structure of 4a was confirmed using x-ray single-crystal structure analysis.