Solute Clusters/Enrichment at the Early Stage of Ageing in Mg-Zn-Gd Alloys Studied by Atom Probe Tomography

Three-dimensional distribution of solute elements in an Mg–Zn–Gd alloy during ageing process is quantitatively characterized by three-dimensional atom probe(3DAP) tomography. Based on the radius distribution function, it is found that Zn–Gd solute pairs in Mg matrix appear mainly at two peaks at early stage of ageing, and the separation distance between Zn and Gd atoms could be well rationalized by the first-principle calculation. Moreover, the fraction of Zn–Gd solute pairs increases first and then decreases due to the precipitation of long-period stacking ordered(LPSO) structures. Both the composition of the structural unit in LPSO structure and the solute enrichment around it are quantified. It is found that Zn and Gd elements are synchronized in the LPSO structure, and solute segregation of pure Zn or Gd is not observed at the transformation front of the LPSO structure in this alloy. In addition, the crystallography of transformation front is further determined by 3DAP data.     

Molecular Imaging of Apoptosis: The Case of Caspase-3 Radiotracers

The molecular imaging of apoptosis remains an important method for the diagnosis and monitoring of the progression of certain diseases and the evaluation of the efficacy of anticancer apoptosis-inducing therapies. Among the multiple biomarkers involved in apoptosis, activated caspase-3 is an attractive target, as it is the most abundant of the executioner caspases. Nuclear imaging is a good candidate, as it combines a high depth of tissue penetration and high sensitivity, features necessary to detect small changes in levels of apoptosis. However, designing a caspase-3 radiotracer comes with challenges, such as selectivity, cell permeability and transient caspase-3 activation. In this review, we discuss the different caspase-3 radiotracers for the imaging of apoptosis together with the challenges of the translation of various apoptosis-imaging strategies in clinical trials.     

帘线钢夹杂物中轻元素F的分析

运用电子探针波谱仪和配置的能谱仪对5.5 mm帘线钢盘条夹杂物中轻元素F进行了点分析和面扫描，结果表明，F元素的质量分数大于5%时，能谱仪与波谱仪的分析结果一致，两者结果均准确可信；F元素质量分数介于1.5%与5%之间时，波谱仪的判定结果更准确；F元素质量分数小于1.5%时，可认为是测量设备的系统误差，不作为判定依据。通过分析钢中夹杂物的典型元素，可确定夹杂物的来源并进行有效控制，从而提高帘线钢的质量。     

反应型HClO/ClO-荧光探针的研究进展

次氯酸/次氯酸根是活性氧化物中重要的信号分子，在生物医药和环境安全等方面发挥着重要作用。反应型荧光探针基于出色的灵敏度、实时成像和生物兼容性好等特点，广泛应用于HClO/ClO^-的检测。本文评述了近5年反应型HClO/ClO^-荧光探针的研究进展，包括反应型HClO/ClO^-荧光探针的设计策略和识别机理，并从HClO/ClO^-引发的反应机理角度（碳碳双键的反应、硫族化合物的反应、醛肟基团的反应、腙/席夫碱的反应、酰肼/磺酰肼的反应、N,N-二甲基硫代氨基甲酸酯的反应和苯硼酸/硼酸酯的反应）概述了反应型HClO/ClO^-荧光探针的特点和实际应用，指出反应型HClO/ClO^-荧光探针的发展方向是合成性能优异的识别基团，构建选择性好、水溶性好、低荧光背景、光化学性能稳定和生物毒性低的反应型近红外HClO/ClO^-荧光探针，实现对生物体内外HClO/ClO^-的可视化检测及机理探索。     

Novel approach to promote the hydrophobic association: Introduction of short alkyl chains into hydrophobically associating polyelectrolytes

A novel approach to promote hydrophobic association by incorporating short alkyl chains onto polyelectrolytes (HAPEs) was presented. A series of HAPEs was synthesized by free radical copolymerization in aqueous media with acrylamide (AM), 11-acrylamidoundecanoic acid (C₁₁AM), and 6-acrylamidohexanoic acid (C₆AM). The structures and compositions of the polymers were confirmed by ¹H-NMR, and the molecular weights were determined by GPC. Results of rheological experiments revealed that viscosities increased greatly in samples containing C₁₁AM and C₆AM compared with the sample without C₆AM. The sample without C₆AM was also characterized by critical association concentrations and critical angular frequencies. Solubilization and bridging interaction were considered as the possible reasons. Pyrene fluorescence probe data and ¹H-NMR spin–spin relaxation times further illustrated the reinforcement of hydrophobic associations by short alkyl side chains. All the results showed that the optimum content of C₆AM was 1 mol % in the prepared HAPEs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47581.     

PLIAP检测化学反应中间生成物机理的探讨

化学反应中间生成物的检测对反应基元步骤、历程和机理的研究有明显的重要性。运用ＰＬＩＡＰ，我们成功地实现了对一些化学反应中间生成物的检测￣［１－４］，搞活ＰＬＩＡＰ能检测化学反应中间生成物的机理对于明确这种检测方法的有效性和扩大其应用有重要意义。本文通过对于运用ＰＬＩＡＰ检测表面催化反应中间生成物的实验条件和结果的分析，初步探讨了用ＰＬＩＡＰ检测表面化学反应中间生成物机理。     

扫描探针显微镜对浓香型成品酒的微观形态探讨

利用扫描探针显微镜的AFM功能,对几种优质浓香型成品白酒的微观形态作了探讨.从AFM扫描图可以看到浓香型成品白酒中的呈香呈味物质成分呈近似圆球状的颗粒形态,并且大小分布错落有致.     

重离子束的Bragg峰定位于麦粒的自由基探针技术

为了实现定点定位诱变，提出了一种利用ＥＳＲ波谱术对离子束Ｂｒａｇｇ峰在麦粒中的定位方法，即自由基探针技术，采用该技术有效地测定出２１ＭｅＶ／ｕ氮离子束的Ｂｒａｇｇ峰位于小麦胚部，注入深度不超过１．０±０．２ｍｍ，而４８ＭｅＶ／ｕ氮离子束贯穿全麦粒，不能实现定点定位诱变。