Weiwei Zhang

© 2015 Zhu and Zhang.Bioorthogonal chemistry has recently emerged to be one of the most powerful tools in drug discovery and chemical biology. The exploration of it has successfully advanced the field of natural product research. In this Perspective, we survey current strategies for the installation of chemical handles into the molecular scaffolds of several major classes of natural products, including polyketides, non-ribosomal peptides, and their hybrids. By tagging these natural products with chemical handles and coupling them with subsequent bioorthogonal reactions, researchers have visualized and studied the mode of action of natural products, as well as synthesized derivatives with better pharmaceutical properties. We conclude this Perspective by considering two questions: Is there a general way to synthesize tagged PKs/NRPs? Does natural product labeling have a broader impact in the field of natural product research beyond current known applications?

This study investigated the concept of individual differences in the use of metacognitive strategies and its relationship with task demand and learner performance within Kormos’ Bilingual Speech Production Model from the lens of Chinese English-as-foreign-language learners in the context of integrated L2 speaking assessment. To measure metacognitive strategies, we administered an inventory on 134 Chinese EFL learners after they completed four integrated L2 speaking assessment tasks. Descriptive analysis and multiple linear regression were adopted for data analysis, and results show that: IDs displayed variance in Chinese EFL learners’ metacognitive strategy use; among the four metacognitive strategies under investigation, problem-solving was reported to be used the most frequently in sharp contrast to monitoring, which had the lowest frequency; metacognitive strategies worked interactively, responding to task demands involved in the four integrated L2 speaking assessment tasks; and Chinese EFL learners’ use of metacognitive strategies, in individual and interactive working modes, had no relationship with their speaking performance. These results are expected to present some insights into the role of IDs in metacognitive strategy use during L2 speech production under assessment conditions, which will add robust evidence to the existing literature on L2 speaking, in particular on metacognitive strategy use in L2 speaking assessment. In the meantime, the findings will provide some empirical validation support for Kormos’ model, which will further provide some implications for L2 speaking instruction and L2 assessment.

Quarantine and isolation at extended length, although considered as highly effective countermeasures for the novel coronavirus which started at the end of 2019, can have great impact on individual's mental health, especially emotional state. The present research recruited 5,115 participants from the general public across 32 provinces and autonomous regions in China in an online survey study, about 20 days after the lockdown of the epicenter, to investigate the relationship between the length of the quarantine and negative affect, as well as the mediating roles of negative cognition, and the moderating roles of dispositional optimism, tolerance of uncertainty, social support, and healthy behavior. The results showed that: Worry and anticipation mediated the relationship between quarantine length and depression and anxiety; Dispositional optimism moderated the path coefficients of quarantine length to worry, worry to anxiety, and anticipation to depression; Tolerance of uncertainty moderated the path coefficient of worry to anxiety; Social support moderated the path coefficient of anticipation to anxiety. In conclusion, during quarantine, dispositional optimism, uncertainty tolerance, and social support can buffer the direct or indirect effects of quarantine length on depression and anxiety. These findings could have profound implications on the societal responses to COVID-19 and future pandemics.

Although memories are more retrievable if observers’ emotional states are consistent between encoding and retrieval, it is unclear whether the consistency of emotional states increases the likelihood of successful memory retrieval, the precision of retrieved memories, or both. The present study tested visual long-term memory for everyday objects while consistent or inconsistent emotional contexts between encoding and retrieval were induced using background grey-scale images from the International Affective Picture System. In the study phase, participants remembered colours of sequentially presented objects in a negative or positive context. In the test phase, participants estimated the colours of previously studied objects in either negative versus neutral or positive versus neutral contexts. Note, IAPS images in the test phase were always visually different from those initially paired with the studied objects. We found that reinstating negative context and positive context at retrieval resulted in better mnemonic precision and a higher probability of successful retrieval, respectively. Critically, these effects could not be attributed to a negative or positive context at retrieval alone. Together, these findings demonstrated dissociable effects of emotion on the quantitative and qualitative aspects of visual long-term memory retrieval.