An Efficient One-Pot Synthesis of Nitriles from Carboxylic Acids Without Solvent Under Microwave Irradiation

Nitriles were prepared from alkyl and aryl carboxylic acids in dry media conditions, under microwave irradiation. Heating of the carboxylic acid, urea and amidosulfonic acid adsorbed on alumina support in a microwave oven affords nitriles in 20–93% yields.     

Trans-2-Diethylphosphoryloxy-1,3-Pentadiene in The Lewis acid Catalyzed Diels-Alder Reaction

Under stannic chloride catalysis, trans-2-diethylphosphoryloxy-1,3-pentadiene (1) undergoes Diels-Alder reaction regio- and stereoselectively with a variety of α,β-unsaturated ketones at low temperature.     

Phosphate Removal from Aqueous Solution by an Effective Clay Composite Material

Adsorption is an effective treatment process for removing phosphorus and thus controlling eutrophication. In this study, a clay composite material called Al–dolomite–montmorillonite (Al–DM) was prepared and characterized. Al–DM performed well with respect to phosphate removal, with its performance depending on the Al–DM loading, contact time, initial phosphorus concentration and initial solution pH. Adsorption mechanisms were investigated by conducting batch tests on phosphate adsorption using the Al–DM. The adsorption process fitted both the pseudo-second-order kinetics model and the intra-particle diffusion model. The Langmuir, Freundlich and BET models all adequately described the adsorption isotherm data. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous in nature. Al–DM is an effective adsorbent for phosphate removal mainly due to its hierarchical porous structures as shown by characterization with SEM and EDS. Chemical changes occurring before and after adsorption in a water environment indicated that Al–DM had little negative effect on water quality.     

Synthesis and Morphology Control of AM‐6 Nanofibers with Tailored ‐V‐O‐V‐ Intermediates

Microporous vanadosilicates with octahedral VO₆ and tetrahedral SiO₄ units, better known as AM‐6, have been hydrothermally synthesized with different morphologies by controlling the Na/K molar ratio of the initial gel mixtures. The morphology of the AM‐6 materials changed from bulky cube to nanofiber aggregates as the Na/K molar ratio decreased from 1.9 to 0.2. Raman spectroscopy revealed that the VO₃^? intermediate species plays an important role in the formation of the nanofiber morphology. The orientation of ‐V‐O‐V‐ chains in nanofiber aggregates was examined by confocal polarized micro‐Raman spectroscopy. It was found that these aggregates are assemblies of short ‐V‐O‐V‐ chains perpendicular to the axis of nanofibers. The obtained AM‐6 nanofibers greatly increase the exposed proportion of V? O terminals, and thus improve the catalytic performance.     

具有变时滞和马尔可夫切换的随机递归神经网络的弱收敛(英文)

本文研究了具有变时滞和马尔可夫切换的随机递归神经网络的弱收敛,通过运用Lyapunov函数、随机分析技巧和推广了的Halanay不等式,得到了上述模型为弱收敛的充分性条件,并且我们揭示了对上述递归神经网络模型所确定的segment过程的转移概率的极限分布是此模型的解过程的唯一的遍历不变概率测度.此外,我们还给出了例子和数值模拟来说明我们结论的正确性.     

C?H Functionalization/Asymmetric Michael Addition Cascade Enabled by Relay Catalysis: Metal Carbenoid Used for C?C Bond Formation

A combination of either ruthenium(II) or rhodium(II) complexes and quinine‐derived squaramide enables 3‐diazooxindoles, indoles, and nitroalkenes to undergo highly efficient asymmetric three‐component reactions, thus affording optically active 3,3′‐bis(indole)s through a consecutive C C bond‐forming sequence, which turned out to be applicable to the facile total synthesis of (−)‐folicanthine.     

Modified 2-window approach for rapid determination of 90Sr and 90Y at low quench level using liquid scintillation counting

⁹⁰Sr is a product of nuclear fission, the radioactivity of which can be determined by liquid scintillation counting (LSC). Because the LSC spectra of ⁹⁰Sr and its daughter ⁹⁰Y overlap each other, the following methods are usually used: (1) measuring immediately after ⁹⁰Sr/⁹⁰Y separation; (2) waiting to reach radioactive equilibrium; (3) adopting the conventional 2-window approach; and (4) using the spectra deconvolution technique. The first one requires ⁹⁰Sr/⁹⁰Y separation and immediate measurement; the second one is time-consuming; the third one is valid only for samples with the same quench level as the calibration standard; the last one is somewhat complicated, and in some cases it is not convenient to export the experimental data to some deconvolution software. Therefore, we have developed a modified 2-window approach to rapidly determine ⁹⁰Sr and ⁹⁰Y in either equilibrium or disequilibrium at low quench level. The key modification of the approach is to provide an LSC spectrum of pure ⁹⁰Y with the same quench level as the sample to be determined. This modification eliminates the need to conduct ⁹⁰Sr/⁹⁰Y separation for the sample itself, to prepare the quench curves, and to fit the LSC spectra with some deconvolution software.     

Sensitive detection of T4 polynucleotide kinase activity based on coupled exonuclease reaction and nicking enzyme-assisted fluorescence signal amplification

As a prominent member of the 5′-kinase family, T4 polynucleotide kinase (PNK) plays an important role in gene function regulations, and the study of PNK activity and its potential inhibitors is significant for research related to the DNA phosphorylation process. Here, we proposed a novel strategy for the detection of PNK activity and its inhibition, which combines exonuclease enzyme reaction and nicking enzyme-assisted fluorescence signal amplification. Through recycling cleavage of DNA fluorescence probe for signal amplification, a highly sensitive PNK sensing platform is developed, and a very low detection limit of 0.05 mU/mL is achieved, which is better than or comparable to that of the previously reported PNK assays. The present approach adopts a simple separation-free procedure in which the enzyme assay is conducted in homogeneous solutions. Additionally, the inhibitory effects of several known kinase inhibitors on PNK have been successfully detected. Since the proposed assay exhibits the advantages of high sensitivity and simplicity, it holds great potential in providing a promising platform for convenient and highly sensitive detection of PNK activity and its inhibitors.

SYNTHESES,CRYSTAL STRUCTURES,AND ANTIMICROBIAL ACTIVITIES OF ZINC COMPLEXES DERIVED FROM 2-AMINO-N′- (PYRIDIN-2-YLMETHYLENE)BENZOHYDRAZIDE

Journal of Structural Chemistry - New zinc complexes, [ZnBr2(HL)] (1), [ZnBr(HL)(NCS)]·0.5H2O (2), [Zn(HL)I2] (3), and [ZnL2] (4), where L is the monoanionic form of...     

Investigation on the Interaction of Dy(Ш)/Rutin Complexes with Bovine Serum Albumin by Spectroscopic Methods

Journal of Solution Chemistry - The interaction between Dy(Ш)/Rutin complexes and bovine serum albumin (BSA) was studied by fluorescence, ultraviolet (UV) absorption, three-dimensional...