Preparing molecularly imprinted nanoparticles of saponins via cooperative imprinting strategy

Saponin is an important class of natural products with various pharmacological activities. The selective separation of saponins is an essential step before further analysis. Molecular imprinting has been an effective strategy for preparing antibody mimics. However, a facile and efficient imprinting strategy for saponins is still lacking owing to their amphiphilic nature. Herein, we have prepared the saponins imprinted nanoparticles via cooperative imprinting strategy. This new strategy relies on the combination of various non‐covalent interactions (hydrophobic and hydrogen bonding) and covalent boronate affinity interactions. The obtained imprinted nanoparticles could rebind specific saponins from complex matrices with good selectivity, superb tolerance to interference, and fast binding equilibrium. This method was verified to be versatile and facile. Thus, this strategy could greatly facilitate the preparation of imprinted nanoparticles for the specific recognition of saponins.     

Theoretical studies of the concentration dependences of d–d transition band,g factors,and local distortion for V4+ in Li2O–PbO–B2O3–P2O5 glasses

In this work, the g factors, d–d transition band, local distortion, and their concentration dependences for impurity V⁴⁺ in 20Li₂O–20PbO–45B₂O₃–(15 − x)P₂O₅:V₂O₅ (0 ≤ x ≤ 2.5 mol%) glasses are theoretically investigated by using perturbation formulas of g factors for a tetragonally compressed octahedral 3d¹ cluster. In the light of the cubic polynomial concentration functions for cubic field parameter D_q, covalency factor N, and relative tetragonal compression ratio ρ, the calculated concentration dependences of d–d transition band and g factors for V⁴⁺ show good agreement with the experimental data. With increasing x, N (≈0.7682–0.8165) displays the monotonously increasing trend, whereas ρ (≈6.5–4.2%) and D_q (≈1504.9–1481.1 cm⁻¹) exhibit the decreasing tendencies. The above concentration dependences can be ascribed to the modifications of the V⁴⁺–O²⁻ bonding and orbital admixtures around the impurity V⁴⁺ due to the effects of V₂O₅ doping on the stability of the glass network, the strength of local crystal fields, and the electron cloud distribution.     

Preparation and performance of (Co,Mn)3O4 spinel coating on Crofer alloy by composite electrodeposition and step-heating thermal conversion

The preparation and performance improvement of the spinel coating on the surface of ferritic alloy is of wide interest for its application in the metallic interconnects of the solid oxide fuel cells (SOFCs). The Co Mn₂O₃ composite coating is prepared on the surface of the Crofer alloy by the composite electrodeposition method. A step-heating thermal conversion process is subsequently used to convert the composite coating into a spinel coating, while a direct-heating process is implemented as the control experiment. Isothermal oxidation tests are then carried out for the prepared samples in order to present the high temperature performance. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and area-specific resistance (ASR) are used to analyze the properties of the matrix and coatings. The experimental results reveal that the coatings by step-heating thermal conversion exhibit better performance of electrical conductivity and oxidation resistance than the coatings by direct-heating process. Furthermore, with the increase of oxidation time, the atomic proportion of Cr element diffusing to the surface of the matrix is maintained at about 3%–4% for the samples with spinel coatings by step heating, which effectively prevent the Cr volatilization in the matrix. The preparation of spinel coatings on the ferritic alloy by composite electrodeposition and step-heating thermal conversion is helpful to stimulate new ideas for the development of reliable and cost-effective metallic interconnect.     

The Core/Shell Structure P Doped MoS2@Ni3S2 Nanorods Array for High Current Density Hydrogen Evolution in Alkaline and Acidic Electrolyte

Electrocatalysis is the most promising strategy to generate clean energy H₂, and the development of catalysts with excellent hydrogen evolution reaction (HER) performance at high current density that can resist strong alkaline and acidic electrolyte environment is of great significance for practical industrial application. Therefore, a P doped MoS₂@Ni₃S₂ nanorods array (named P-NiMoS) was successfully synthesized through successive sulfuration and phosphorization. P-NiMoS presents a core/shell structure with a heterojunction between MoS₂ (shell) and Ni₃S₂ (core). Furthermore, the doping of P modulates the electronic structure of the P-NiMoS; the electrons transfer from the t_2g orbital of Ni element to the e_g empty orbital of Mo element through the Ni−S−Mo bond at the Ni₃S₂ and MoS₂ heterojunction, facilitating the hydrogen evolution reaction. As a result, P-NiMoS exhibits excellent HER activity; the overpotential is 290 mV at high current density of 250 mA cm⁻² in alkaline electrolyte, which is close to Pt/C (282 mV@250 mA cm⁻²), and P-NiMoS can stably evolve hydrogen for 48 h.     

基于DenseNet的散射成像景深拓展研究

针对拼接干涉测量技术除了引入拼接误差，还将引入机械运动误差的问题，为此提出一种X射线反射镜的非零位干涉测量方法，无需拼接便可实现零回程误差的高精度干涉测量。利用一块高精度平面镜来标定干涉系统在全视场范围内的回程误差。通过将待测非球面镜划分成多个子孔径，每个子孔径可近似看作一个平面，这样可以从标定数据库中找到该子孔径所对应的回程误差，通过简单的矩阵拼接可得到整个待测非球面镜的回程误差。以X射线椭圆柱面反射镜为例进行实验，实现X射线椭圆柱面反射镜非零位干涉测量面形的回程误差有效标定，相比于拼接干涉测量方法二者结果一致性较好，证实所提方法的正确性。     

Luminescence Switching of Organogold(I) Complexes between Aggregation-induced Phosphorescence Enhancement and Aggregation-caused Quenching by Balancing Auxiliary Ligands around the AuI Center

Attaching AIE-active L1 ([1,1′:2′,1′′:4′′,1′′′-quaterphenyl]-2-yldiphenylphosphane) to AuCl, shortened the distances of P−C bonds to promote electron cloud overlap between Au^I and L1 , affords 1 ( L1 AuCl) with aggregation-induced phosphorescence enhancement (AIPE) activity by ³LMCT transitions. Then substituting the coplanar L2 (9-ethynylanthracene) for the Cl⁻ in 1 providing 2 , switches the luminescence to aggregation-caused quenching (ACQ) activity. Furthermore, we restore the performance from ACQ to AIPE by metathesis reactions to transfer 2 into 1 . It is versatile synthetic strategy of reversible transformation between 1 and 2 that switches the luminescence of organogold(I) between AIPE and ACQ through balancing auxiliary ligands around the given metal.     

Heat transfer simulation in cavity of twin screw compressor under coupling of clearance leakage-heat by utilizing fuzzy beamlet finite element model

Journal of Thermal Analysis and Calorimetry - In order to optimize structure of twin screw compressor, and improve the working efficiency of twin screw refrigeration compressor, the heat transfer...     

Co/ZnO/N-C composites obtained by ZIF derived from Co-Zn oxides as highly efficient catalyst for reduction of p-nitrophenol

Journal of Sol-Gel Science and Technology - Zinc oxide (ZnO) and cobalt (Co)-ZnO nanocomposites were first reacted with 2-Methylimidazole to synthesize the zeolitic imidazole frameworks as...     

Bandgaps and vibration isolation of local resonance sandwich-like plate with simply supported overhanging beam

Applied Mathematics and Mechanics - The concept of local resonance phononic crystals proposed in recent years provides a new chance for theoretical and technical breakthroughs in the structural...     

细胞松弛素B阻断微核法鉴定男性个体辐射敏感性的方法初探

初步研究了男性个体辐射敏感性的鉴定方法及标准。采集50名男性志愿者的外周血，分别给予不同剂量X射线照射，采用细胞松弛素B阻断双核法测定微核率(MNF)，通过二阶多项拟合法，绘制微核剂量效应选项中心标准曲线，将个人微核剂量效应曲线与标准曲线比对后判断个体辐射敏感性。 $0.0\sim2.5 $ Gy剂量范围内，剂量效应二阶多项拟合的中心方程为(MNF=0.014 7+0.036 2D+0.023 1D 2， r=0.726)。50名志愿者中，辐射敏感的有13人，辐射抗性的有14人，基本符合正态分布。Spearman秩和相关分析结果显示，MNF在各个辐射剂量点与辐射敏感性均存在正相关,与辐射抗性呈负相关,MNF随剂量增加而增加。本研究初步建立了“以线代点”男性个体辐射敏感性鉴定方法,并发现男性外周血淋巴细胞的本底微核率与个体辐射敏感性呈正相关。