Near‐Infrared Activated Black Phosphorus as a Nontoxic Photo‐Oxidant for Alzheimer's Amyloid‑β Peptide

The inhibition of amyloid‐β (Aβ) aggregation by photo‐oxygenation has become an effective way of treating Alzheimer's disease (AD). New near‐infrared (NIR) activated treatment agents, which not only possess high photo‐oxygenation efficiency, but also show low biotoxicity, are urgently needed. Herein, for the first time, it is demonstrated that NIR activated black phosphorus (BP) could serve as an effective nontoxic photo‐oxidant for amyloid?β peptide in vitro and in vivo. The nanoplatform BP@BTA (BTA: one of thioflavin‐T derivatives) possesses high affinity to the Aβ peptide due to specific amyloid selectivity of BTA. Importantly, under NIR light, BP@BTA can significantly generate a high quantum yield of singlet oxygen (¹O₂) to oxygenate Aβ, thereby resulting in inhibiting the aggregation and attenuating Aβ‐induced cytotoxicity. In addition, BP could finally degrade into nontoxic phosphate, which guarantees the biosafety. Using transgenic Caenorhabditis elegans CL2006 as AD model, the results demonstrate that the ¹O₂‐generation system could dramatically promote life‐span extension of CL2006 strain by decreasing the neurotoxicity of Aβ.     

浅谈景观水体处理

对当前景观水处理工艺进行了总结,并对各种处理方法的原理进行了阐述,同时对各种处理方法的优缺点进行了分析,以便根据不同的情况采用合理有效的处理方法,从而保持景观水的清澈、洁净,美化了生活环境。     

地下水除铁锰装置的工艺设计及其应用

本文介绍了地下水除铁锰装置的工艺设计、原理及流程安装、操作程序，并根据应用实例，证明了含铁锰过量的地下水，采用充氧曝气接触催化氧化法处理后，其水质符合国家ＧＢ５７４９－８５规定的饮用水标准。     

平板膜式氧合器中氧传质系数近似计算的积分法

应用Graetz-Leveque问题的前进边界理论的修正近似解,进一步分析了半透膜阻力对氧传质速率的影响,获得了与Graetz-Leveque问题精确解非常接近的(相对偏差在6.58%以下)用于计算平板膜式氧合器中氧传质系数的简单分析表达式.并提出了基于氧传质速率计算的该类氧合器通道长度设计的临界判据.     

链条炉分层燃烧的数值模型与计算

针对分层燃烧的特点在单粒径模型基础上建立了双粒径链条锅炉层燃模型,并在实际锅炉上进行实验验证,双粒径模型能更好地模拟安装分层煤斗后煤层的燃烧特性。利用改进后的双粒径模型来模拟普通煤斗和分层煤斗的进煤方式对燃烧的影响,结果表明:双粒径模型能很好地模拟出大、小颗粒同时存在时床层的燃烧特性,分层堆叠的方式有利于煤层的引燃并加强燃尽,分层燃烧的灰渣含碳量是9.54%,混合燃烧的灰渣含碳量是15.81%。     

350 MW超临界机组锅炉氧化皮防治技术研究

为减少350 MW超临界机组因锅炉氧化皮脱落而引起的堵塞爆管问题,针对某电力公司8台超临界煤粉锅炉的结构型式及运行工况展开调查研究,分析结构设计对锅炉高温受热面蒸汽侧氧化皮的影响,发现烟温偏差的叠加效应是引起高温再热器汽温偏差大和局部氧化皮生成过快的主要原因,针对锅炉高温受热面的SA-213TP347H不锈钢管材的金属壁温适用范围进行对比,确定其最佳金属壁温报警值为600℃;通过对锅炉给水加氧设备进行改造,控制给水含氧量在10~20μg/L范围内,确保高温受热面蒸汽侧含氧量为零。实践证明,采取上述氧化皮防治措施后,锅炉氧化皮堆积数量同比减少85%以上。     

超临界机组的合金管蒸汽侧氧化膜生长与剥落研究进展

超临界机组高温合金管氧化膜剥落问题是困扰机组安全与经济运行的难题,严重制约了机组蒸汽参数和效率的提高。特别是,在超临界机组采用给水加氧处理方式(OT)后,奥氏体不锈钢管内壁氧化膜大面积剥落事故屡见不鲜,尤以TP347H合金管为甚。本文总结了近年来国内外针对超临界机组合金管氧化膜研究的进展及相关成果,首先介绍了超临界蒸汽环境中合金管氧化机理和原子迁移机制,综述了铁素体和奥氏体合金表面氧化膜的形貌特征,分析了蒸汽溶氧对氧化膜生长速率、形貌和缺陷的影响。氧化膜完整性是决定合金抗腐蚀性能的重要因素,但在机组运行过程中氧化膜应力破坏了氧化膜完整性。进一步总结了国内外氧化膜应力和剥落研究的数值分析及实验研究情况,为我国超临界机组氧化膜剥落故障诊断研究提供参考。     

河流微孔曝气系统充氧性能优化试验EI北大核心CSCD

针对河流微孔曝气系统复氧效率较低的问题,基于单因素试验和响应面优化试验,以氧体积传质系数为评价指标,研究了曝气系统氧传质过程中微孔曝气器孔径、曝气水深、盐度、BOD_(5)及表面活性剂十二烷基苯磺酸钠(SDBS)质量浓度对充氧性能的影响规律,并建立了多元二次回归模型,对曝气参数进行优化。结果表明:5种因素对氧体积传质系数均有影响,其影响的显著程度由大到小分别为曝气水深、SDBS质量浓度、盐度、微孔曝气器孔径、BOD_(5)质量浓度;微孔曝气器孔径和SDBS质量浓度、盐度和SDBS质量浓度之间存在显著的交互作用;模型预测值与试验值的相对误差在合理范围内,所建立的回归模型准确可靠。     

Kinetic Analysis of Terminal and Unactivated C?H Bond Oxyfunctionalization in Fatty Acid Methyl Esters by Monooxygenase‐Based Whole‐Cell Biocatalysis

The alkane monooxygenase AlkBGT from Pseudomonas putida GPo1 constitutes a versatile enzyme system for the ω‐oxyfunctionalization of medium chain‐length alkanes. In this study, recombinant Escherichia coli W3110 expressing alkBGT was investigated as whole‐cell catalyst for the regioselective biooxidation of fatty acid methyl esters to terminal alcohols. The ω‐functionalized products are of general economic interest, serving as building blocks for polymer synthesis. The whole‐cell catalysts proved to functionalize fatty acid methyl esters with a medium length alkyl chain specifically at the ω‐position. The highest specific hydroxylation activity of 104 U g_CDW⁻¹ was obtained with nonanoic acid methyl ester as substrate using resting cells of E. coli W3110 (pBT10). In an optimized set‐up, maximal 9‐hydroxynonanoic acid methyl ester yields of 95% were achieved. For this specific substrate, apparent whole‐cell kinetic parameters were determined with a V_max of 204±9 U g_CDW⁻¹, a substrate uptake constant (K_S) of 142±17 μM, and a specificity constant V_max/K_S of 1.4 U g_CDW⁻¹ μM ⁻¹ for the formation of the terminal alcohol. The same E. coli strain carrying additional alk genes showed a different substrate selectivity. A comparison of biocatalysis with whole cells and enriched enzyme preparations showed that both substrate availability and enzyme specificity control the efficiency of the whole‐cell bioconversion of the longer and more hydrophobic substrate dodecanoic acid methyl ester. The efficient coupling of redox cofactor oxidation and product formation, as determined in vitro, combined with the high in vivo activities make E. coli W3110 (pBT10) a promising biocatalyst for the preparative synthesis of terminally functionalized fatty acid methyl esters.