Recent progress in separation prediction of counter‐current chromatography

As a liquid‐liquid partition chromatography, counter‐current chromatography has advantages in large sample loading capacity without irreversible adsorption, which has been widely applied in separation and purification fields. The main factors, including partition coefficient, two‐phase solvent systems, apparatus, and operating parameters greatly affect the separation process of counter‐current chromatography. To promote the applications of counter‐current chromatography, it is essential to develop theoretical research to master the principles of counter‐current chromatographic separations so as to achieve predictions before laborious trials. In this article, recent progress about separation prediction methods are reviewed from a point of the steady and unsteady state of the mass transfer process of counter‐current chromatography and its mass transfer characteristics, and then it is divided into three aspects: prediction of partition coefficient, modeling the thermodynamic process of counter‐current chromatography, and modeling the dynamic process of counter‐current chromatography.     

Synthesis,Characterization and Biological Evaluation of New 3,5-Disubstituted-Pyrazoline Derivatives as Potential Anti-Mycobacterium tuberculosis H37Ra Compounds

A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (¹H, ¹³C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c–5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand–receptor interactions, and to hypothesize potential refinements for the compound.     

Upgrading Solid Digestate from Anaerobic Digestion of Agricultural Waste as Performance Enhancer for Starch-Based Mulching Biofilm

Developing a green and sustainable method to upgrade biogas wastes into high value-added products is attracting more and more public attention. The application of solid residues as a performance enhancer in the manufacture of biofilms is a prospective way to replace conventional plastic based on fossil fuel. In this work, solid digestates from the anaerobic digestion of agricultural wastes, such as straw, cattle and chicken manures, were pretreated by an ultrasonic thermo-alkaline treatment to remove the nonfunctional compositions and then incorporated in plasticized starch paste to prepare mulching biofilms by the solution casting method. The results indicated that solid digestate particles dispersed homogenously in the starch matrix and gradually aggregated under the action of a hydrogen bond, leading to a transformation of the composites to a high crystalline structure. Consequently, the composite biofilm showed a higher tensile strength, elastic modulus, glass transition temperature and degradation temperature compared to the pure starch-based film. The light, water and GHG (greenhouse gas) barrier properties of the biofilm were also reinforced by the addition of solid digestates, performing well in sustaining the soil quality and minimizing N₂O or CH₄ emissions. As such, recycling solid digestates into a biodegradable plastic substitute not only creates a new business opportunity by producing high-performance biofilms but also reduces the environmental risk caused by biogas waste and plastics pollution.     

Computational studies on two novel energetic nitrogen‐rich compounds based on tetrazolone

Two novel energetic nitrogen‐rich compounds 1,4‐diaminotetrazol‐5‐one ( DATO ) and 1,4‐dinitrotetrazol‐5‐one ( DNTO ) were proposed first and studied by quantum chemistry method with B3LYP/6‐31G* level of theory. The optimized geometry, IR predicted spectrum and thermochemical parameters, frontier molecular orbitals and molecular electrostatic potential were calculated for inspecting the electronic structure, molecular stability and chemical reactivity. The important macroscopic properties including density, enthalpy of formation, detonation parameters and impact sensitivity have been predicted as well. As a result, two designed compounds DATO and DNTO possess positive enthalpy of formation (395.79 and 342.77 kJ/mol), impressive detonation parameters (D = 8.80 km/s, P = 33.69 GPa; D = 8.89 km/s, P = 34.98 GPa) superior to the remarkable explosive RDX, acceptable sensitivities and might be promising candidates of energetic materials. Copyright © 2015 John Wiley & Sons, Ltd.     

超薄宽带平面聚焦超表面及其在高增益天线中的应用

针对相位梯度超表面在灵活操控电磁波与提高天线增益中的潜在应用,提出一种新型的宽带超表面单元,实现了在较宽频带范围内操控电磁波波前与提高天线增益.本文首先设计了一种圆环十字形对称单元来控制反射波的相移量,单元厚度为1 mm,尺寸为0.3λ_0(λ_0=20 mm),工作频段15—18 GHz,而后验证了由该单元组成的相位梯度超表面在15—18 GHz范围内对电磁波的奇异反射与聚焦特性.最后将设计的反射聚焦超表面应用于提高天线增益中,仿真与测试结果均表明,天线最高增益在15—18 GHz内平均增加了11 d B且-1 dB增益带宽为15—18 GHz(相对带宽为18.2%).由于厚度薄、重量轻、频带宽,设计的该单元拓展了相位梯度超表面在微波领域的应用,有望为高增益天线的实现提供新的方法.     

High-resolution in vivo imaging of blood vessels without labeling

We demonstrate that both oxyhemoglobin and deoxyhemoglobin have sequential two-color, two-photon absorption properties that can serve as endogenous contrasts in microvasculature imaging. Using a sensitive modulation transfer technique, we are able to image hemoglobin in red blood cells with micrometer resolution, both in vitro and in vivo. We show that excellent contrast from hemoglobin without any labeling can be obtained in tissue.     

有序排列PMMA 模板法合成三维有序纳米孔道MgO

"利用由无乳化剂的乳液聚合法和水浮法联用技术合成得到的有序排列的聚甲基丙烯酸甲酯(PMMA)微球为硬模板,以硝酸镁为镁源,并采用硝酸镁-柠檬酸-乙醇混合溶液浸渍PMMA微球后经干燥以及先后在300 ℃恒温灼烧3 h和500 ℃恒温灼烧5 h,制备出具有有序纳米孔道结构的MgO粒子．应用X射线衍射、高分辨扫描电子显微镜、透射电子显微镜/选区电子衍射以及N2吸附-脱附法等技术表征了PMMA和MgO样品的物理化学性质．结果表明,所得PMMA微球颗粒较为均匀,粒径约为284 nm,且排列规整有序．由PMMA硬模板     

Improving the sensitivity of cellulose fiber-based lateral flow assay by incorporating a water-dissolvable polyvinyl alcohol dam

Cellulose - Lateral flow assay (LFA) is an important point-of-care (POC) test platform due to the associated portability, on-site testing, and low cost for diagnosis of pathogen infections and...     

A cost-effective anionic flocculant prepared by grafting carboxymethyl cellulose and lignosulfonate with acrylamide

How to efficiently utilize most abundant biomass of cellulose, lignin and their derivatives has become an emerging challenge as the anticipative oil depletion. In this paper, the ternary anionic copolymer of carboxymethyl cellulose-acrylamide-lignosulfonate (CAL) was successfully prepared by hydrothermal polymerization. Based on the flocculation characteristics of cationic methylene blue, the optimal polymerization process was confirmed as the raw material ratio of 1:1:1, initiator dosage of 0.9 wt %, the reaction time was 5 h and the reaction temperature was 55 °C. The results showed that the decolorization ratio was 87.5% at the CAL dosage of 600 mg/L for the 500 mg/L methylene blue simulated wastewater. The CAL achieved fast flocculation kinetics and super color removal ratios in the wide ranges of environmental pH, temperature and salt concentration. The flocculation mechanism is single charge neutralization. Moreover, the estimated treatment cost of CAL is 68.3% lower than that of commercial anionic PAM. The prepared anionic CAL flocculant has the characteristics of environmental safety, excellent flocculation performance and cost-effectiveness, which shows great potential in the field of dye wastewater treatment, and also provides a feasible way for the effective utilization of biomass resources.

     

基于柔性碳纳米管压阻膜的无线加速度检测系统

通过对加速度检测的重大意义进行分析,得出了加速度检测仪的价值和意义,介绍了本系统的设计思路和应用前景。传感器采用了基于纳米技术的碳纳米管薄膜感应前端,拓宽了传感器设备的研发领域,同时应用无线传感技术,使系统进一步实用化。最后介绍了本系统的实验情况,以及具体应用的效果。