家电下乡售后服务存在的问题及对策     

阮学云 《科技广场》2010,(12)

家电下乡作为一项全新的支农惠农政策,在有效促进家电生产、流通和农民需求三者有机对接的同时,随着政策的不断深入,也曾暴露出一些缺陷和弊端,出现了短期销售业绩显著、长期增长乏力等问题。基于我国目前家电下乡政策实施现状,本文就其售后服务环节上所存在的不足进行了初步归纳并提出了相关解决方案。  相似文献   

Engineering G-quadruplex aptamer to modulate its binding specificity     

Long Li  Shujuan Xu  Xueyu Peng  Yuzhuo Ji  He Yan  Cheng Cui  Xiaowei Li  Xiaoshu Pan  Lu Yang  Liping Qiu  Jianhui Jiang  Weihong Tan 《国家科学评论(英文版)》2021,8(4)

The use of aptamers in bioanalytical and biomedical applications exploits their ability to recognize cell surface protein receptors. Targeted therapeutics and theranostics come to mind in this regard. However, protein receptors occur on both cancer and normal cells; as such, aptamers are now taxed with identifying high vs. low levels of protein expression. Inspired by the flexible template mechanism and elegant control of natural nucleic acid-based structures, we report an allosteric regulation strategy for constructing a structure-switching aptamer for enhanced target cell recognition by engineering aptamers with DNA intercalated motifs (i-motifs) responsive to the microenvironment, such as pH. Structure-switching sensitivity can be readily tuned by manipulating i-motif sequences. However, structure-switching sensitivity is difficult to estimate, making it equally difficult to effectively screen modified aptamers with the desired sensitivity. To address this problem, we selected a fluorescent probe capable of detecting G-quadruplex in complicated biological media.  相似文献