Ziwei Wang

© 2016, American Society for Biochemistry and Molecular Biology Inc. All rights reserved.Glycyl-tRNA synthetase is the enzyme that covalently links glycine to cognate tRNA for translation. It is of great research interest because of its nonconserved quaternary structures, unique species-specific aminoacylation properties, and noncanonical functions in neurological diseases, but none of these is fully understood. We report two crystal structures of human GlyRS variants, in the free form and in complex with tRNAGly respectively, and reveal new aspects of the glycylation mechanism. We discover that insertion 3 differs considerably in conformation in catalysis and that it acts like a "switch" and fully opens to allow tRNA to bind in a cross-subunit fashion. The flexibility of the protein is supported by molecular dynamics simulation, as well as enzymatic activity assays. The biophysical and biochemical studies suggest that human GlyRS may utilize its flexibility for both the traditional function and alternative functions.

Purpose: The study aims to investigate the effectiveness of various strategies used by English teachers in Harbin, China, to improve ESL students' English pronunciation. It highlights the importance of effective pronunciation skills for ESL students' overall language proficiency, especially in listening, and seeks to identify how teachers address challenges in teaching oral language skills. Approach/Methodology/Design: A qualitative research design was employed, using interviews with a sample of four teachers selected through purposive sampling. The data collected were analyzed using thematic analysis to explore both the challenges faced by students in pronunciation and the strategies teachers use to overcome these issues. Findings: The study identified several challenges that students face, including phonetic difficulties, limited opportunities for speaking practice, and anxiety or shame associated with making mistakes. Teachers also encountered barriers, such as curriculum limitations, inadequate resources, and lack of institutional support. Key strategies identified as effective included role-playing, audio-visual aids, and adaptable teaching methods tailored to specific classroom needs. Practical Implications: The study suggests that to improve pronunciation, teachers should foster a supportive language environment, focus on motivational techniques, incorporate multimedia resources, and employ learner-centered approaches. It calls for more resources and institutional backing to support these strategies, emphasizing that an engaged and flexible teaching approach is crucial for effective pronunciation instruction. Originality/value: This research contributes to the field by underlining the need for a holistic approach to pronunciation teaching that adapts to the unique needs of ESL students in a non-English-speaking context. It highlights the importance of teacher training and diverse teaching methods to improve pronunciation outcomes, offering insights into how a supportive and resource-rich environment can enhance language learning effectiveness.

This study focuses on learning effects between firms connected by common ownership. We explore the learning effects in a certain setting that how decision-makers in focal firms learn from punishments for fraudulent disclosure in their co-owned firms. Baseline results show that punishments for fraudulent disclosure in co-owned firms reduce information disclosure fraud in focal firms. The effects still exist after excluding other potential channels of learning. In mechanism analyses, similarities between focal firms and their co-owned firms and influential common shareholders enhance the learning effects. Further, after the events in co-owned firms, there is improvement in internal control in focal firms, which contributes to the reduction of fraudulent disclosure. Additionally, empirical results mitigate the concern that the reduction of fraud is not driven by the learning argued in this paper but decision-makers alternatively conducting more other unethical behaviors such as real earnings management. In sum, empirical results support the existence of learning effects. As common ownership is an important but highly underexplored linkage between firms, future research can study learning effects between firms connected by common ownership in other suitable settings.

Trend and change-point analyses of water quality time series data have important implications for pollution control and environmental decision-making. This paper developed a new approach to assess trends and change-points of water quality parameters by integrating locally weighted polynomial regression and segmented regression. Firstly, LWPR was used to pretreat the original water quality data into a smoothed time series to represent the long-term trend of water quality. Then, SegReg was used to identify the long-term trends and change-points of the smoothed time series. Finally, statistical tests were applied to determine the significance of the long-term trends and change-points. The efficacy of this approach was validated using a 10-year record of total nitrogen and chemical oxygen demand from Shanxi Reservoir watershed in eastern China. Results showed that this approach was straightforward and reliable for assessment of long-term trends and change-points on irregular water quality datasets. The reliability was verified by statistical tests and practical considerations for Shanxi Reservoir watershed. The newly developed integrated LWPR-SegReg approach is not only limited to the assessment of trends and change-points of water quality parameters but also has a broad application to other fields with long-term time series records.

© 2014 Nature America, Inc. All rights reserved. Using genome-wide data from 253,288 individuals, we identified 697 variants at genome-wide significance that together explained one-fifth of the heritability for adult height. By testing different numbers of variants in independent studies, we show that the most strongly associated 1/42,000, 1/43,700 and 1/49,500 SNPs explained 1/421%, 1/424% and 1/429% of phenotypic variance. Furthermore, all common variants together captured 60% of heritability. The 697 variants clustered in 423 loci were enriched for genes, pathways and tissue types known to be involved in growth and together implicated genes and pathways not highlighted in earlier efforts, such as signaling by fibroblast growth factors, WNT/I 2-catenin and chondroitin sulfate-related genes. We identified several genes and pathways not previously connected with human skeletal growth, including mTOR, osteoglycin and binding of hyaluronic acid. Our results indicate a genetic architecture for human height that is characterized by a very large but finite number of causal variants.

Electron cryomicroscopy has been used to determine the atomic coordinates from density maps of biological assemblies. These models can be assessed by their overall fit to the experimental data and stereochemical information. However, these models do not annotate the actual density values of the atoms nor their positional uncertainty. Here, we introduce a computational procedure to derive an atomic model from a cryo- EM map with annotated metadata. The accuracy of such a model is validated by a faithful replication of the experimental cryo-EM map computed using the coordinates and associated metadata. The functional interpretation of any structural features in the model and its utilization for future studies can be made in the context of its measure of uncertainty. We applied this protocol to the 3.3-Å map of the mature P22 bacteriophage capsid, a large and complex macromolecular assembly.With this protocol, we identify and annotate previously undescribed molecular interactions between capsid subunits that are crucial to maintain stability in the absence of cementing proteins or cross-linking, as occur in other bacteriophages.

Plasmon-generated hot carriers are used in photovoltaic or photochemical applications. However, the interplays between the plasmon and single-particle excitations in nanosystems have not been theoretically addressed using ab initio methods. Here we show such interplays in a Ag 55 nanocluster using real-time time-dependent density functional theory simulations. We find that the disappearance of the zero-frequency peak in the Fourier transform of the band-to-band transition coefficient is a hallmark of the plasmon. We show the importance of the d-states for hot-carrier generations. If the single-particle d-to-s excitations are resonant to the plasmon frequency, the majority of the plasmon energy will be converted into hot carriers, and the overall hot-carrier generation is enhanced by the plasmon; if such resonance does not exist, we observe an intriguing Rabi oscillation between the plasmon and hot carriers. Phonons play a minor role in plasmonic dynamics in such small systems. This study provides guidance on improving plasmonic applications.