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Herein, we have developed a dual amplification strategy for ultrasensitive detection of DNA combining exonuclease III (Exo III)-assisted reaction and DNAzyme motor. DNA probes are carefully designed; thus, target recognition and the first amplification cycle are accomplished simultaneously, which makes the operation very convenient. Moreover, the self-powered DNAzyme motor may translate a single binding event into cleavage of multiple fluorescence probes, which significantly heightens the signal intensity. As a result, the limit of detection as low as 21 fM is achieved. The fluorescence intensity is found to have a linear relationship with respect to the logarithm of DNA concentration in a wide range from 100 fM to 10 nM. This proposed method shows great potential for the applications of biological studies and clinical diagnosis.

With the rapid growth of online shopping platforms, more and more customers intend to share their shopping experience and product reviews on the Internet. Both large quantity and various forms of online reviews bring difficulties for potential consumers to summary all the heterogenous reviews for reference. This paper proposes a new ranking method through online reviews based on different aspects of the alternative products, which combines both objective and subjective sentiment values. Firstly, weights of these aspects are determined with LDA topic model to calculate the objective sentiment value of the product. During this process, the realistic meaning of each aspect is also summarized. Then, consumers’ personalized preferences are taken into consideration while calculating total scores of alternative products. Meanwhile, comparative superiority between every two products also contributes to their final scores. Therefore, a directed graph model is constructed and the final score of each product is computed by improved PageRank algorithm. Finally, a case study is given to illustrate the feasibility and effectiveness of the proposed method. The result demonstrates that while considering only objective sentiment values of the product, the ranking result obtained by our proposed method has a strong correlation with the actual sales orders. On the other hand, if consumers express subjective preferences towards a certain aspect, the final ranking is also consistent with the actual performance of alternative products. It provides a new research idea for online customer review mining and personalized recommendation.