Single cell analysis is of great significance to understand the physiological activity of organisms.Microfluidic droplet is an ideal analytical platform for single-cell analysis. We developed a microfluidic droplet splitting system integrated with a flow-focusing structure and multi-step splitting structures to form 8-line droplets and encapsulate single cells in the droplets. Droplet generation frequency reached1021 Hz with the aqueous phase flow rate of 1 m L/min and the oil phase flow rate of 15 mL /min. Relative standard deviation of the droplet size was less than 5% in a single channel, while less than 6% in all the8 channels. The system was used for encapsulating human whole blood cells. A single-cell encapsulation efficiency of 31% was obtained with the blood cell concentration of 2.5× 10~4cells/mL, and the multicellular droplet percentage was only 1.3%. The multi-step droplet splitting system for single cell encapsulation featured simple structure and high throughput. 相似文献
Based on the generalized gradient approximation (GGA), Perdew-Wang-91 (PW91) combined with a periodic slab model has been applied to study the catalytic activity of chlorine evolution on TinRumO2(1 1 0) surface. Metal oxide model TinRumO2 has been established with pure TiO2 and RuO2 on the basis set of Double Numerical plus polarization (DNP), in which the proportion of n:m was 3:1, 1:1, or 1:3. Analysis on the reaction activity in the electrochemical reaction and the electrochemical desorption reaction was based on Frontiermolecular orbital theory. The results show that the TinRumO2 with a ratio of Ti:Ru at 3:1 is best facilitates the electrochemical reaction and electrochemical desorption reaction to produce M-Clads intermediate and precipitate Cl2. In addition, the adsorption energy of Cl on the surface of Ti3Ru1O2 possesses the minimum value of 2.514 eV, and thus electrochemical desorption reaction could occur most easily. 相似文献
Graphene nanoribbons (GNRs) with a non‐zero bandgap are regarded as a promising candidate for the fabrication of electronic devices. In this study, large‐scale solution synthesis of narrow GNRs was firstly achieved by the intramolecular cyclodehydrogenation of kinked tetraphenylethene (TPE) polymer precursors prepared by A2B2‐type Suzuki‐Miyaura polymerization. After the cyclization reaction, the nanoribbons have a better conjugation than the twisted polymer precursor, resulting in obvious red shift in UV/vis absorption and photoluminescence (PL) spectra. The efficient formation of conjugated nanoribbons was also investigated by Raman, FTIR spectroscopy, and microscopic studies. Furthermore, such structurally well‐defined GNRs have been successfully developed for top‐gated field‐effect transistor (FET) by directly solution processing. The AFM images show that the prepared‐GNRs thin films form crystalline fibrillar intercalating networks, which can effectively facilitate the charge transport. These FET devices with ion‐gel gate dielectrics exhibit low‐voltage operation (<5 V) with excellent mobility up to 0.41 cm2·V?1·s?1 and an on‐off ratio of 3×104, thus opening up new opportunities for flexible GNRs‐based electronic devices. 相似文献
An on-line solid phase extraction-high performance liquid chromatography-tandemmass spectrometry method for the analysis of perfluoroalkyl substances (PFASs) in water samples was developed. The optimal analytical conditions were obtained through the optimization of the extraction efficiency of online solid phase extraction column, sample loading rate and loading volume, and the concentration of ammonium acetate in mobile phase. Under the optimal condition, the analytical method displayed good linearity (r2 > 0.99) for 12 PFASs (C5-C14 perfluoroalkyl carboxylic acids and C6/C8 perfluoroalkyl sulfonic acids) over a concentration range of 0.5-100 ng/L. The limits of quantitation for samples were between 0.025 ng/L and 0.5 ng/L and the relative standard deviations (RSD) of five consecutive analyses were less than 10% for 1 ng/L standard solution. Satisfactory results were obtained using this analytical method for the analysis of perfluoroalkyl substances in Antarctic ice core samples. The recoveries of all perfluoroalkyl substances were in a range of 73%-117% when the sampleswere spiked with standards at the concentrations of 2.5 ng/L and 25 ng/L. 相似文献
SiO2-supported Ni-Mo bimetallic phosphides were prepared by temperature-programmed reduction(TPR) method from the phosphate precursors calcined at different temperatures. Their properties were characterized by means of ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS), H2temperature-programmed reduction(H2-TPR), X-ray diffraction(XRD), transmission electron microscopy(TEM), CO chemisorption, H2 and NH3temperature-programmed desorptions(H2-TPD and NH3-TPD). Their catalytic performances for the deoxygenation of methyl laurate were tested in a fixed-bed reactor. When the precursors were calcined at 400 and 500?C, respectively, Ni Mo P2 phase could be formed apart from Ni2 P and Mo P phases in the prepared C400 and C500 catalysts. However, when the precursors were calcined at600, 700 and 800°C, respectively, only Ni2 P and Mo P phases could be detected in the prepared C600, C700 and C800 catalysts. Also, in C400, C500 and C600 catalysts, Mo atoms were found to be entered in the lattice of Ni2 P phase, but the entering extent became less with the increase of calcination temperature. As the calcination temperature of the precursor increased, the interaction between Ni and Mo in the prepared catalysts decreased, and the phosphide crystallite size tended to increase, subsequently leading to the decrease in the surface metal site density and the acid amount. C600 catalyst showed the highest activity among the tested ones for the deoxygenation of methyl laurate. As the calcination temperature of the precursor increased, the selectivity to C12 hydrocarbons decreased while the selectivity to C11 hydrocarbons tended to increase. This can be mainly attributed to the decreased Ni-Mo interaction and the increased phosphide particle size. In sum, the structure and performance of Ni-Mo bimetallic phosphide catalyst can be tuned by the calcination temperature of precursor. 相似文献
A quantitative analysis of multiple components with a single‐marker method was established for the simultaneous determination of five sesqutiterpenoids in Xingnaojing injection. This method was established with Xingnaojing injection determined by high‐performance liquid chromatography coupled with diode array detection. The durability and system suitability of the established method were evaluated, and the reliable relative correction factors were obtained with curdione selected as an internal reference. The contents of the five components in all Xingnaojing injections were determined by external standard method and the contents of curcumenone, curcumenol, curzerenone, and germacrone were also calculated with the obtained relative correction factors. Then, relative error was investigated to estimate the difference of the two methods. As a result, the established new method possesses good adaptability, and there is no significant difference between the two methods, except for the content of curzerenone in eight samples. To put the established method into practice, the limits of quantitation of the established method of the five components were proposed and defined. Thus, the developed methodology can also be utilized to the quality evaluation of Xingnaojing injection, in spite of the difference found in the content of curzerenone between the external standard method and the newly established method. 相似文献
A simple route is reported to synthesize colloidal particle clusters (CPCs) from self‐assembly of in situ poly(vinylidene fluoride)/poly(styrene‐co‐tert‐butyl acrylate) [PVDF/P(St‐co‐tBA)] Janus particles through one‐pot seeded emulsion single electron transfer radical polymerization. In the in situ Pickering‐like emulsion polymerization, the tBA/St/PVDF feed ratio and polymerization temperature are important for the formation of well‐defined CPCs. When the tBA/St/PVDF feed ratio is 0.75 g/2.5 g/0.5 g and the reaction temperature is 35 °C, relatively uniform raspberry‐like CPCs are obtained. The hydrophobicity of the P(St‐co‐tBA) domains and the affinity of PVDF to the aqueous environment are considered to be the driving force for the self‐assembly of the in situ formed PVDF/P(St‐co‐tBA) Janus particles. The resultant raspberry‐like CPCs with PVDF particles protruding outward may be promising for superhydrophobic smart coatings.