Steric Engineering of Alkylthiolation Side Chains to Finely Tune Miscibility in Nonfullerene Polymer Solar Cells

Morphology and miscibility control are still a great challenge in polymer solar cells. Despite physical tools being applied, chemical strategies are still limited and complex. To finely tune blend miscibility to obtain optimized morphology, chemical steric engineering is proposed to systemically investigate its effects on optical and electronic properties, especially on a balance between crystallinity and miscibility. By changing the alkylthiol side chain orientation different steric effects are realized in three different polymers. Surprisingly, the photovoltaic device of the polymer PTBB‐m with middle steric structure affords a better power conversion efficiency, over 12%, compared to those of the polymers PTBB‐o and PTBB‐p with large or small steric structures, which could be attributed to a more balanced blend miscibility without sacrificing charge‐carrier transport. Space charge‐limited current, atomic force microscopy, grazing incidence wide angle X‐ray scattering, and resonant soft X‐ray scattering measurements show that the steric engineering of alkylthiol side chains can have significant impacts on polymer aggregation properties, blend miscibility, and photovoltaic performances. More important, the control of miscibility via the simple chemical approach has preliminarily proved its great potential and will pave a new avenue for optimizing the blend morphology.     

Patterned Wettability Surface for Competition‐Driving Large‐Grained Perovskite Solar Cells

Novel photovoltaic perovskite solar cells (PSCs) with high‐efficient photovoltaic property are largely in thrall to the uncertain perovskite grain size and inevitable defects. Here, inspired by the competitive growth between tree and grass in the forest system, a competitive perovskite grain growth approach via micro‐contact print (MicroCP) method (CD disk as templates) for printing wettability‐patterned substrate is proposed, aiming to achieve large‐grained perovskite and avoid discontinuous perovskite films caused by the low wettability of substrates. A MicroCP process is employed to construct a patterned wettability surface for the perovskite competitive growth mechanism on the electrode surface. This approach modifies the substrates quickly, ensures the uniform coverage of perovskite due to the function of ‐NH₂ and Pb²⁺ bonds, and converts the perovskite films composed of small grains and pinholes into high‐quality perovskite films, free from pinholes and made up of large grains, resulting in efficiencies over 20% for the MicroCP PSCs.     

A high-throughput screening method for improved R-2-(4-hydroxyphenoxy)propionic acid biosynthesis

Bioprocess and Biosystems Engineering - R-2-(4-hydroxyphenoxy)propionic acid (R-HPPA) is a key intermediate of the enantiomerically pure phenoxypropionic acid herbicides. R-HPPA could be...     

两个不同启动子及其组合对碱性蛋白酶AprE异源表达的影响

背景:碱性蛋白酶(alkaline protease)是一种具有广泛用途的工业酶制剂,其发酵活力目前仍不能满足工业生产需要。目的:旨在通过优化启动子及其组合来提高Bacillus subtilis WB600中碱性蛋白酶AprE的产量。方法:以Bacillus subtilis WB600为出发菌株,成功构建了含有4种不同类型启动子(P1、P2、P-1-2、P-2-1)的碱性蛋白酶AprE表达菌株。结果:含不同启动子的4株重组菌均可成功表达碱性蛋白酶,发酵48h,含单一启动子P2的重组菌株表达碱性蛋白酶的活力为4 041U/ml,是P1的1. 23倍。双启动子重组菌B. subtilis WB600/P-2-1-aprE表达的酶活性最高,是双启动子P-1-2的1. 35倍,达到了6 125U/ml。结论:为工业化高产碱性蛋白酶提供了一种有效策略。     

经皮肝穿刺胆道引流术与逆行胰腺胆管造影术对结石性梗阻性黄疸患者的疗效比较研究

目的:比较经皮肝穿刺胆道引流术(PTCD)与逆行胰腺胆管造影术(ERCP)对结石性梗阻性黄疸患者的治疗效果。方法:选取海军军医大学第三附属医院东方肝胆外科医院于2016年3月～2018年4月间收治的结石性梗阻性黄疸患者80例。按照介入治疗术式的异同将患者分为ERCP组(n=40,给予ERCP治疗)和PTCD组(n=40,给予PTCD治疗),记录两组手术时间、术中出血量、住院费用、住院时间、治疗成功率、黄疸缓解率、并发症发生情况,比较两组术前、术后1 d、术后7 d肝功能指标情况。结果:两组患者手术时间、术中出血量、治疗成功率、黄疸缓解率比较差异无统计学意义(P0.05),ERCP患者住院费用少于PTCD组患者,住院时间亦短于PTCD组患者(P0.05)。两组患者术后1 d、术后7 d丙氨酸转氨酶(ALT)、总胆红素(TBIL)、直接胆红素(DBIL)水平均较术前降低,且两组患者术后7 d上述指标水平低于术后1 d(P0.05),ERCP组术后1 d、术后7 d ALT、TBIL、DBIL水平与PTCD组比较差异无统计学意义(P0.05)。两组患者术后并发症总发生率比较差异无统计学意义(P0.05)。结论:PTCD、ERCP治疗结石性梗阻性黄疸,均能有效改善患者临床症状和肝功能,且手术安全性相当,但ERCP可明显减少住院时间和住院费用。     

Nuclear fast red‐based colorimetric sensors for sensitive and selective detection of Ag ions

The reduction of nuclear fast red (NFR) stain by sodium tetrahydroboron was catalyzed in the presence of silver ions (Ag⁺). The fluorescence properties of reduced NFR differed from that of NFR. The product showed fluorescence emission at 480 nm with excitation at 369 nm. Furthermore, the fluorescence intensity of the mixture increased strongly in the presence of Ag⁺ and Britton–Robinson buffer at pH 4.78. There was a good linear relationship between increased fluorescence intensity (ΔI) and Ag⁺ concentration in the range 5.0 × 10^?9 to 5.0 × 10^?8 M. The correlation coefficient was 0.998, and the detection limit (3σ/k) was 1.5 × 10^?9 M. The colour of the reaction system changed with variation in Ag⁺ concentration over a wide range. Based on the colour change, a visual semiquantitative detection method for recognition and sensing of Ag⁺ was developed for the range 1.0 × 10^?8 to 5.0 × 10^?4 M, with an indicator that was visible to the naked eye. Therefore, a sensitive, simple method for determination of Ag⁺ was developed. Optimum conditions for Ag⁺ detection, the effect of other ions and the analytical application of Ag⁺ detection of synthesized sample were investigated.