Synthesis,Anticancer Activity,Structure-Activity Relationship and Mechanistic Investigations of Falcarindiol Analogues

Forty samples of optically active falcarindiol analogues are synthesized by using the easily available C2 symmetric (R)- and (S)-1,1’-binaphth-2-ol (BINOL) in combination with Ti(OⁱPr)₄, Zn powder and EtI. Their anticancer activities on Hccc-9810, HepG2, MDA-MB-231, Hela, MG-63 and H460 cells are assayed to elucidate their structure-activity relationships. These results showed that the falcarindiol analogue (3R,8S)- 2 i with the terminal double bond has the most potent anti-proliferation effect on Hccc-9810 cells with IC₅₀ value of 0.46 μM. The falcarindiol analogue (3R,8S)- 2 i can induce obvious Hccc-9810 cell apoptosis in a concentration-dependent manner by Hoechst staining and flow cytometry analysis. The proposed mechanism suggests that the falcarindiol analogue (3R,8S)- 2 i increases LDH release and MDA content, and reduces the levels of SOD activity, which lead to the accumulation of oxidative stress and induce apoptosis in Hccc-9810 cells.     

The generalized Dice similarity measures for Pythagorean fuzzy multiple attribute group decision making

The Pythagorean fuzzy set (PFS) is characterized by two functions expressing the degree of membership and the degree of nonmembership, which square sum of them is equal or less than 1. It was proposed as a generalization of a fuzzy set to deal with indeterminate and inconsistent information. In this study, we shall present some novel Dice similarity measures of PFSs and the generalized Dice similarity measures of PFSs and indicates that the Dice similarity measures and asymmetric measures (projection measures) are the special cases of the generalized Dice similarity measures in some parameter values. Then, we propose the generalized Dice similarity measures-based multiple attribute group decision-making models with Pythagorean fuzzy information. Then, we apply the generalized Dice similarity measures between PFSs to multiple attribute group decision making. Finally, an illustrative example is given to demonstrate the efficiency of the similarity measures for selecting the desirable ERP system.     

微量Zr对不对称轧制Al-0.8Mg-0.9Si合金板织构及性能的影响

本文研究了微量Zr对不对称轧制Al-0.8Mg-0.9Si合金板及其相继固溶处理后的微观结构及性能的影响。结果表明：微量Zr在Al-0.8Mg-0.9Si合金中形成Al3Zr相弥散分布在基体中,在不对称轧制过程中,该化合物相对Copper{112}<111>、Brass{011}<211>、S{123}<634>、E{111}<110>和F{111}<112>等形变织构无明显影响；在随后的固溶处理过程中,轧制板材发生的再结晶使得Copper、Brass、S等形变织构的取向密度降低,但不溶的细小Al3Zr相在一定程度上抑制了不连续再结晶行为,反而使轧制过程中形成的E、F剪切织构的取向密度增加。添加微量Zr所形成的上述结构使该合金板材在固溶后获得较好的综合性能,其抗拉强度、屈强比和延伸率分别可达230MPa、0.49和9.5%以上；塑性应变比r值从0.7提高至0.84,杯突值IE由8.94提高至9.84,各向异性度|Δr|由0.15降低至0.04。     

基于非对称磁镀材料线圈的无线输电系统

煤矿井下有线供电有很多弊端，急需将无线输电技术及系统应用于煤矿井下，但是目前常规对称线圈结构难以满足矿井的特殊需求。基于非对称磁镀材料线圈的磁耦合谐振式无线输电系统并分析其传输效率，针对无线输电系统实际应用中常有的发射端线圈与接收端线圈尺寸有较大差异且位置有水平偏移的问题，进行了分析与研究。提出在常规两线圈结构间加入与发射线圈同轴共面的中继线圈，同时采用五层结构的磁镀导线代替铜导线进行线圈绕制，并建立了系统模型。进行了无线输电系统的互感分析及与常规两线圈系统的比对，对磁镀导线结构相较于普通铜线减少能量损耗的优势进行了分析及仿真。对加入特定位置线圈且使用磁镀导线的无线输电系统及原始两线圈系统进行了构建过程中各阶段的系统模拟仿真及室内实验。认为提出的加入特定位置线圈及采用磁镀导线的方法对非对称的磁耦合无线输电系统的传输效率有明显积极作用，构建的基于磁镀导线且加入特定位置线圈的非对称磁耦合无线输电系统即使结构不对称，仍能保持很高的传输效率，相较于常规两线圈系统而言，传输效率得到显著提升。     

基于正交试验的非对称垂直轴水轮机数值模拟

运用正交试验法开展了具有非对称NACA翼型的垂直轴潮流能水轮机的非定常数值模拟研究,分析弯度、弯度位置、前缘半径、最大厚度位置对叶轮能量提取率的影响。使用极差分析法确定了各因素影响的主次顺序和各尖速比下由最优参数确定的翼型。结果表明:在不同尖速比下,弯度是影响水轮机性能的主导因素,对水轮机能量提取率的贡献率分别为44.7%(尖速比λ=2.25)、53.4%(尖速比λ=2.5)和59.4%(尖速比λ=2.75);次要因素为最大厚度所在位置,其余两个参数对其性能影响较小。针对最优参数确定的翼型进行验证,结果证实具有该翼型的水轮机的动力学性能要好于其他翼型。     

Numerical simulation and experimental research on heat transfer and flow resistance characteristics of asymmetric plate heat exchangers

The asymmetric plate heat exchanger (APHE) has the possibility of achieving balanced pressure drops on both hot and cold sides for situations with unbalanced flow, which may in turn enhance the heat transfer. In this paper, the single-phase water flow and heat transfer of an APHE consisted of two types of plates are numerically (400≤Re≤12000) and experimentally (400≤Re≤ 3400) investigated. The numerical model is verified by the experimental results. Simulations are conducted to study the effects of N, an asymmetric index proposed to describe the geometry of APHEs. The correlations of the Nusselt number and friction factor in the APHEs are determined by taking N and working fluids into account. It is found that an optimal N exists where the pressure drops are balanced and the heat transfer area reaches the minimum. The comparison between heat transfer and flow characteristics of the APHEs and the conventional plate heat exchanger (CPHE) is made under various flow rate ratios of the hot side and the cold side and different allowable pressure drops. The situations under which APHE may perform better are identified based on a comprehensive index Nu/f^1/3.     

Optimal approximation of asymmetric type fractional-order bandpass Butterworth filter using decomposition technique

In this letter, the optimal rational approximation of fractional-order bandpass Butterworth filter (FOBBF) is presented. The transfer function of the FOBBF is decomposed into a multiplication of first-order and second-order terms. As a result, the design stability conditions can be easily satisfied using only the variable boundary constraints. The proposed technique generalizes the symmetric fractional-order roll-off characteristic as only a special case of the asymmetric one. Several examples are presented to validate the modeling efficacy.     

A rational asymmetric hollow fiber membrane for oxygen permeation

A typical oxygen permeation hollow fiber membrane fabricated by phase inversion-based extrusion process demonstrates heterogeneous porous microstructures, in which the surface layer with relatively low porosity is used as a separation layer after sintering. It is usually not convenient to control the thickness of separation layer. And a high sintering temperature is needed to densify the separation layer, which in turn could destroy the desired porous microstructures in other portion. This paper studies a novel process to fabricate multilayer asymmetric hollow fiber membrane with a rational design using 67 vol. % Gd_0.2Ce_0.8O_2−δ−33 vol. % La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (GDC-LSCF) as a model material system. The phase inversion-based extrusion process in open literature is employed to fabricate a hollow fiber substrate featuring radially well-aligned microchannels open at the inner surface. Built upon the hollow fiber substrate, a thin dense separation layer and porous surface catalyst layer at shell side are then fabricated through dip-coating and sintering process alternatively. The oxygen permeation flux of the fabricated hollow fiber membrane reaches 2.68 mL/cm²/min at 900°C under Ar/air gradient, the highest performance of the membranes with GDC-LSCF material system in open literature. The innovative fabrication process is able to readily control the thickness of functional layers while decreasing sintering temperatures.     

Significant Role of Al in Ternary Layered Double Hydroxides for Enhancing Electrochemical Performance of Flexible Asymmetric Supercapacitor

The Al effect on the electrochemical properties of layered double hydroxides (LDHs) is not properly probed, although it is demonstrated to notably promote the capacitive behavior of LDHs. Herein, ternary NiCo₂Al_x layered double hydroxides with varying levels of Al stoichiometry are purposely developed, grown directly on mechanically flexible and electrically conducting carbon cloth (CC@NiCo₂Al_x‐LDH). Al plays a significant role in determining the structure, morphology, and electrochemical behavior of NiCo₂Al_x‐LDHs. At an increasing level of Al in NiCo₂Al_x‐LDHs, there is a steady evolution from 1D nanowire to 2D nanosheets. The CC@NiCo₂Al‐LDH at an appropriate level of Al and with the nanowire–nanosheet mixed morphology exhibits both significantly enhanced electrochemical performance and excellent structural stability, with about a 2.3‐fold capacitance of NiCo₂‐OH. When applied as the anode in a flexible asymmetric supercapacitor (ASC), the CC@NiCo₂Al‐LDH gives rise to a remarkable energy density of 44 Wh kg^?1 at the power density of 462 W kg^?1, together with remarkable cyclic stability with 91.2% capacitance retention over 15 000 charge–discharge cycles. The present study demonstrates a new pathway to significantly improve the electrochemical performance and stability of transition metal LDHs, which are otherwise unstable in structure and poorly performing in both rate and cycling capability.     

Crossing the Border: From Keto- to Imine Reduction in Short-Chain Dehydrogenases/Reductases

The family of NAD(P)H-dependent short-chain dehydrogenases/reductases (SDRs) comprises numerous biocatalysts capable of C=O or C=C reduction. The highly homologous noroxomaritidine reductase (NR) from Narcissus sp. aff. pseudonarcissus and Zt_SDR from Zephyranthes treatiae, however, are SDRs with an extended imine substrate scope. Comparison with a similar SDR from Asparagus officinalis (Ao_SDR) exhibiting keto-reducing activity, yet negligible imine-reducing capability, and mining the Short-Chain Dehydrogenase/Reductase Engineering Database indicated that NR and Zt_SDR possess a unique active-site composition among SDRs. Adapting the active site of Ao_SDR accordingly improved its imine-reducing capability. By applying the same strategy, an unrelated SDR from Methylobacterium sp. 77 (M77_SDR) with distinct keto-reducing activity was engineered into a promiscuous enzyme with imine-reducing activity, thereby confirming that the ability to reduce imines can be rationally introduced into members of the “classical” SDR enzyme family. Thus, members of the SDR family could be a promising starting point for protein approaches to generate new imine-reducing enzymes.