抗抑郁药帕罗西汀的合成研究进展

本文综述了抗抑郁药帕罗西汀及其中间体的合成研究进展．     

Development of hydrides for motor vehicles

The storage of hydrogen in metal hydrides is suitable for motor vehicles as well as for stationary applications. Since the metal hydrides are used both for fuel and for heat storage some interesting technical developments are possible. The development and applications of low and high temperature hydrides are reported and the solutions of some technical problems (e.g. improvement of heat transfer and hydride manufacture) are presented.     

An Efficient Supervised Deep Hashing Method for Image Retrieval

In recent years, searching and retrieving relevant images from large databases has become an emerging challenge for the researcher. Hashing methods that mapped raw data into a short binary code have attracted increasing attention from the researcher. Most existing hashing approaches map samples to a binary vector via a single linear projection, which restricts the flexibility of those methods and leads to optimization problems. We introduce a CNN-based hashing method that uses multiple nonlinear projections to produce additional short-bit binary code to tackle this issue. Further, an end-to-end hashing system is accomplished using a convolutional neural network. Also, we design a loss function that aims to maintain the similarity between images and minimize the quantization error by providing a uniform distribution of the hash bits to illustrate the proposed technique’s effectiveness and significance. Extensive experiments conducted on various datasets demonstrate the superiority of the proposed method in comparison with state-of-the-art deep hashing methods.     

Theoretical and Experimental Study on the Thermal Insulation Performance of the Roof with Water-Retained Bricks

In this paper, the thermal insulation performance of the roof with water-retained bricks was first analyzed theoretically with respect to the thermal inertia, attenuation and delay time of the roof with water-retained bricks. Then, the experimental rig was established to carry out the experimental research on the thermal insulation performance of the roof with and without water-retained bricks on the sunny, overcast and rainy days in the summer and on the sunny day in the winter. The results showed that: (1) the surface heat storage coefficient is affected by the evaporating heat transfer of the water layer; (2) the thermal inertness, attenuation and delay time of the roof with water-retained bricks are 2.575, 21 and 6.94 h, respectively, when the water depth is 2 cm; (3) on the sunny, overcast and rainy days in the summer, laying water-retained bricks can enhance the heat insulation performance of the roof, and can improve the thermal comfort of the loft; and (4) on the sunny day in the winter, after laying water-retained bricks, the average temperature of the loft in 24 h increases by 2.3 °C, and the temperature fluctuation of the loft decreases by 56.0%. Therefore, the thermal insulation effect is significantly improved after laying water-retained bricks on the roof from the results of both the theoretical and experimental study.     

Separation and Purification of Two Saponins from Paris polyphylla var. yunnanensis by a Macroporous Resin

An effective method for separating and purifying critical saponins (polyphyllin II and polyphyllin VII) from a Paris polyphylla var. yunnanensis extract was developed in this study which was environmentally friendly and economical. Static adsorption kinetics, thermodynamics, and the dynamic adsorption-desorption of macroporous resins were investigated, and then the conditions of purification and separation were optimized by fitting with an adsorption thermodynamics equation and a kinetic equation. Effective NKA-9 resin from seven macroporous resins was screened out to separate and purify the two saponins. The static adsorption and dynamic adsorption were chemical and physical adsorption dual-processes on the NKA-9 resin. Under the optimum parameters, the contents of polyphyllin II and polyphyllin VII in the product were 17.3-fold and 28.6-fold those in plant extracts, respectively. The total yields of the two saponins were 93.16%. This research thus provides a theoretical foundation for the large-scale industrial production of the natural drugs polyphyllin II and polyphyllin VII.     

Effects of Fatty Alcohols with Different Chain Lengths on the Performance of Low pH Biomass-Based Foams for Radioactive Decontamination

Compared with polymers and nanoparticles, fatty alcohols can not only increase the stability of foam, but also maintain better foamability at pH < 2, which is beneficial to reduce waste liquid and increase decontamination efficiency for radioactive surface pollution. However, different fatty alcohols have different hydrophobic chain lengths. The effects of fatty alcohols with different chain lengths on the performance of decontamination foam were studied at pH < 2, to assist in the selection of suitable fatty alcohols as foam stabilizers. Combined with betaine surfactant and phytic acid, biomass-based foams were synthesized using fatty alcohols with different chain lengths. When the hydrophobic tail groups of the fatty alcohol and the surfactant were the same, the foam showed the best performance, including the lowest surface tension, the highest liquid film strength, the greatest sag-resistance and the best stability. However, when the hydrophobic tail groups were different, the space between adjacent surface active molecules was increased by thermal motion of the excess terminal tail segments (a tail-wagging effect), and the adsorption density reduced on the gas-liquid interface, leading to increased surface tension and decreased liquid film strength, sag-resistance and stability. The use of decontamination foam stabilized by fatty alcohols with the same hydrophobic group as the surfactant was found to increase the decontamination rate of radioactive uranium pollution from 64 to over 90% on a vertical surface.     

Urea Synthesis from Isocyanides and O-Benzoyl Hydroxylamines Catalyzed by a Copper Salt

In the presence of CuOAc, a series of unsymmetric ureas can be generated in moderate to good yields under mild reaction conditions (10 mol% of CuOAc, 2 equiv t-BuONa or PhONa, 30 °C), using aryl isocyanides and O-benzoyl hydroxylamines as the readily accessible starting materials. The reactions might undergo a cascade process involving isocyanide insertion into the N-O bond and Mumm-type rearrangement. This work represents a rare example of isocyanide insertion into N-O bonds, which would extend isocyanide insertion chemistry.     

Programmable mismatch-fueled high-efficiency DNA signal amplifier

Herein, by introducing mismatches, a high-efficiency mismatch-fueled catalytic multiple-arm DNA junction assembly (M-CMDJA) with high-reactivity and a high-threshold is developed as a programmable DNA signal amplifier for rapid detection and ultrasensitive intracellular imaging of miRNA. Compared with traditional nucleic acid signal amplification (NASA) with a perfect complement, the M-CMDJA possesses larger kinetic and thermodynamic favorability owing to the more negative reaction standard free energy (ΔG) as driving force, resulting in much higher efficiency and rates. Once traces of the input initiator react with the mismatched substrate DNA, it could be converted into amounts of output multiple-arm DNA junctions via the M-CMDJA as the functional DNA conversion nanodevice. Impressively, the mismatch-fueled catalytic four-arm DNA junction assembly (M-CFDJA) exhibits high conversion efficiency up to 1.05 × 10⁸ in 30 min, which is almost ten times more than those of conventional methods. Therefore, the M-CMDJA could easily address the challenges of traditional methods: slow rates and low efficiency. In application, the M-CFDJA as a DNA signal amplifier was successfully used to develop a biosensing platform for rapid miRNA detection with a LOD of 6.11 aM and the ultrasensitive intracellular imaging of miRNA, providing a basis for the next-generation of versatile DNA signal amplification methods for ultimate applications in DNA nanobiotechnology, biosensing assay, and clinical diagnoses.

We proposed an ingenious mismatch-enhanced catalytic multiple-arm DNA junction assembly (M-CMDJA) which possesses more negative reaction standard free energy (ΔG) as the driving force, resulting in quite high conversion efficiency and much faster reaction speed.     

Effect of ultrasound on ammonium leaching of zinc from galmei ore

The effect of ultrasound on ammonium leaching of zinc from galmei has been investigated. The use of an ultrasonic field allows the leaching time to be decreased by a factor of ten on account of the decrease in the diffusion layer thickness on the surface of the galmei which has been leached.