New photocrosslinkable polymers for second-order nonlinear optics

Among all the strategies developed by chemists to stabilize NLO properties of poled amorphous polymeric films, one of the most efficient is the formation of a network into which NLO moieties are covalently bound by both ends after their alignment under a DC electric field. For that purpose, complementary chemical groups can be used, reacting either thermally or photochemically. In our work, the use of photocrosslinkable groups (cinnamate and furylacrylate) has been investigated. In that case, photocrosslinking reactions occur between the photocrosslinkable groups functionalized into NLO molecules and the same photocrosslinkable groups appended via an alkyl spacer group into a polymer acting as the matrix. After synthesis of the different compounds and film realization, the photocrosslinking process was characterized by UV-visible spectroscopy, thus giving evidence of the higher efficiency of the furylacrylate-based system with respect to the cinnamate-based one. The alkyl spacer group was recognized as playing a crucial role in furthering the dimerization reactions between the polymer and the NLO moieties. Evolution of the maximal absorption band corresponding to the NLO moiety itself (around 500 nm) was interpreted through UV-visible spectroscopic studies using different model compounds. This was not due to NLO moiety damage, as first feared, but only to a modification in the surrounding polarity during the crosslinking process. The furylacrylate-based system was then poled and photocrosslinked in the poled state, yielding a material with excellent optical quality and very stable optical nonlinearity.     

框架眼镜联合角膜塑形镜矫正青少年高度近视的临床疗效及对角膜内皮细胞和泪膜的影响

目的:探讨框架眼镜联合角膜塑形镜矫正青少年高度近视的临床疗效及对角膜内皮细胞和泪膜的影响.方法:选取2018年1月～2019年3月期间我院收治的青少年高度近视患者98例(181眼),根据信封抽签法分为对照组49例92眼(框架眼镜配戴治疗)和观察组49例89眼(对照组基础上联合角膜塑形镜治疗).对比两组裸眼视力、屈光度、...     

放射自显影技术应用的现状及未来趋势

放射自显影通常指结合了放射标记探针的分子或组织通过感光材料（如X光胶片）曝光、显影、定影获得金属银颗粒图像的实验技术，它是定性、定量分析与探针结合的靶分子含量及其在组织中分布的传统手段，在生物学基础研究以及临床前新药研究等方面有着广泛的应用。近年来磷屏成像技术的普及显著缩短了放射自显影技术的实验周期，并拓展了在短半衰期正电子放射核素中的应用。本文重点介绍放射自显影技术应用中尚不能全面被非放射性替代技术取代的一些实验工作进展，主要包括某些酶活性的测定、磷酸化位点分析、低丰度核酸检测以及与放射性探针特异结合的靶点（如受体等）在组织中的分布等实验技术工作。适应当前应用趋势的变化对放射示踪共用技术平台的建设，对帮助技术支撑人员提供更好的、具有针对性的技术性服务具有一定的指导意义。