9 results on '"Yaowen Liu"'
Search Results
2. Electrochemical C−H deuteration of pyridine derivatives with D2O
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Zhiwei Zhao, Ranran Zhang, Yaowen Liu, Zile Zhu, Qiuyan Wang, and Youai Qiu
- Subjects
Science - Abstract
Abstract Herein, we develop a straightforward, metal-free, and acid-/base-free electrochemical C4-selective C − H deuteration of pyridine derivatives with economic and convenient D2O at room temperature. This strategy features an efficient and environmentally friendly approach with high chemo- and regioselectivity, affording a wide range of D-compounds, such as pyridines, quinolones, N-ligands and biorelevant compounds. Notably, the mechanistic experiments and cyclic voltammetry (CV) studies demonstrate that N-butyl-2-phenylpyridinium iodide is a crucial intermediate during the electrochemical transformation, which provides a general and efficient way for deuteration of pyridine derivatives.
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- 2024
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3. Strain-modulated magnetic droplet precession in spin-torque nano-oscillators
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Sai Zhou, Cuixiu Zheng, Haoxiang Xu, and Yaowen Liu
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Physics ,QC1-999 - Abstract
In this paper, we present a promising method for modulating the frequency of magnetic droplets using strain induced by an adjacent piezoelectric layer. This strain results in significant changes in droplet frequency (∼6 GHz) and variations in diameter or mode, while maintaining a fixed current density of 1.4×10^{12}A/m^{2} under both high and low fields. By applying strain pulses, we successfully modulate the magnetic droplet frequency, paving the way for potential implementation of digital binary frequency shift-keying modulation technique with magnetic droplets. Moreover, the effects of Oersted field and the Zhang-Li torque induced by lateral current have also been discussed, showing a minimal impact on the oscillation frequencies, especially at high fields.
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- 2024
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4. Aging related obesity and type 2 diabetes mellitus suppress neuromuscular communication and aggravate skeletal muscle dysfunction in rhesus monkeys
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Shaoxia Pu, Yaowen Liu, Wenjun Wu, Fei Sun, Hongsheng Lu, Xiaocui Xu, Yanhua Su, Wenming Cheng, and Haizhen Wang
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Rhesus monkeys ,Obesity ,Type 2 diabetes ,Aging ,Muscle proteome ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Age-related functional deterioration in skeletal muscle raises the risk for falls, disability, and mortality in the elderly, particularly in obese people or those with type 2 diabetes mellitus (T2D). However, the response of the skeletal muscle to transitioning from obesity to diabetes remains poorly defined, despite that obesity is classified as a stage of pre-diabetes. We screened and selected spontaneously obese and diabetic rhesus monkeys and examined altered protein expression in skeletal muscle of healthy aging (CON), obesity aging (OB), and type 2 diabetes mellitus aging (T2D) rhesus monkeys using Tandem Mass Tags (TMT)-based quantitative proteomic analysis. In total, we identified 142 differentially expressed proteins. Muscle-nerve communication proteins were firstly suppressed at obese-stage. With the disintegration of skeletal muscle, mitochondrial complex I and other energy homeostasis relate proteins were significantly disordered at T2D stage. Indicating that aging related obesity suppressed muscle-nerve communication and contribute to T2D related functional deterioration of skeletal muscles in elderly rhesus monkeys. Some alterations of muscular functional regulator are detected in both obesity and T2D samples, suggesting some T2D related skeletal muscular hypofunctions are occurring at obesity or pre-obesity stage. Muscle-nerve communication proteins and muscular function related proteins could be potential therapy target or early diagnose marker of for skeletal muscular hypofunctions in aging obesity populations.
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- 2024
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5. Pineapple Detection with YOLOv7-Tiny Network Model Improved via Pruning and a Lightweight Backbone Sub-Network
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Jiehao Li, Yaowen Liu, Chenglin Li, Qunfei Luo, and Jiahuan Lu
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object detection ,neural network ,YOLOv7-tiny ,lightweight ,model pruning ,pineapple detection ,Science - Abstract
High-complexity network models are challenging to execute on agricultural robots with limited computing capabilities in a large-scale pineapple planting environment in real time. Traditional module replacement often struggles to reduce model complexity while maintaining stable network accuracy effectively. This paper investigates a pineapple detection framework with a YOLOv7-tiny model improved via pruning and a lightweight backbone sub-network (the RGDP-YOLOv7-tiny model). The ReXNet network is designed to significantly reduce the number of parameters in the YOLOv7-tiny backbone network layer during the group-level pruning process. Meanwhile, to enhance the efficacy of the lightweight network, a GSConv network has been developed and integrated into the neck network, to further diminish the number of parameters. In addition, the detection network incorporates a decoupled head network aimed at separating the tasks of classification and localization, which can enhance the model’s convergence speed. The experimental results indicate that the network before pruning optimization achieved an improvement of 3.0% and 2.2%, in terms of mean average precision and F1 score, respectively. After pruning optimization, the RGDP-YOLOv7-tiny network was compressed to just 2.27 M in parameter count, 4.5 × 109 in computational complexity, and 5.0MB in model size, which were 37.8%, 34.1%, and 40.7% of the original YOLOv7-tiny network, respectively. Concurrently, the mean average precision and F1 score reached 87.9% and 87.4%, respectively, with increases of 0.8% and 1.3%. Ultimately, the model’s generalization performance was validated through heatmap visualization experiments. Overall, the proposed pineapple object detection framework can effectively enhance detection accuracy. In a large-scale fruit cultivation environment, especially under the constraints of hardware limitations and limited computational power in the real-time detection processes of agricultural robots, it facilitates the practical application of artificial intelligence algorithms in agricultural engineering.
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- 2024
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6. Magnon Excitation Modes in Ferromagnetic and Antiferromagnetic Systems
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Xing Chen, Cuixiu Zheng, and Yaowen Liu
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magnon spintronics ,antiferromagnets ,magnetization dynamics ,ferromagnetic resonance ,magnon-magnon coupling ,Chemistry ,QD1-999 - Abstract
Magnons, recognized as the quanta of spin waves, offer a pathway for transmitting information without the need for electron motion, thus emerging as a leading candidate for the next generation of low-power electronics. Firstly, this study gives an overview by examining magnon modes possessing infinite wavelengths or zero wave numbers (known as ferromagnetic resonance) in classical ferromagnetic, antiferromagnetic, and synthetic antiferromagnetic systems. It delves into the dynamics of magnetization, particularly focusing on magnetic moments precession and the corresponding dispersion relationships under two distinct acoustic and optic eigenmodes. Furthermore, it elaborates on a novel hybrid quantum system termed magnon-magnon coupling. The study elucidates the mechanism behind the robust coupling between acoustic and optic magnon modes. Finally, we briefly discuss the current challenges and future research directions in this field.
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- 2024
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7. Sub-terahertz excitations in a synthetic antiferromagnet with perpendicular anisotropy
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Cuixiu Zheng, Chao Chen, Shanshan Hu, Sai Zhou, Hao-Hsuan Chen, and Yaowen Liu
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Biotechnology ,TP248.13-248.65 ,Physics ,QC1-999 - Abstract
In this paper, micromagnetic simulations are employed to investigate terahertz (THz) magnetic excitations in a spin torque nano-oscillator (STNO) with a perpendicularly magnetized synthetic antiferromagnetic (SAF) free layer. The magnetization precession of the free layer can be finely tuned into the sub-THz range without the necessity of external magnetic fields. The excited frequency exhibits two distinctive regions, namely region-I and region-II, depending on the applied current strength. In region-I, characterized by relatively small currents, the two ferromagnetic layers are stabilized at two separate precession orbits. The frequency in this region decreases with current strength, exhibiting similar features as the Néel vector change observed in antiferromagnets. In contrast, region-II is defined by currents where the two ferromagnetic layers synchronize into the same precession orbit. The frequency increases with current, correlating with the variation in the net magnetization of the SAF layer. An analytical model is developed through the canonical transformation of Lagrange’s equation, which can describe the frequency dependence on both the applied current and the antiferromagnetic interlayer coupling strengths. The simulations and the analytical model show good agreement, offering a more profound understanding of the magnetic excitation properties in STNOs with ultrathin SAF free layers. These insights are crucial for the design of advanced terahertz spintronic devices.
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- 2024
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8. Impact of exercise training on gut microbiome imbalance in obese individuals: a study based on Mendelian randomization analysis
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Haonan Qian, Yuxin Zuo, Shixiong Wen, Xilong Wang, Yaowen Liu, and Tianwei Li
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gut microbiome ,exercise ,microbial community ,causality ,Mendelian randomization ,Physiology ,QP1-981 - Abstract
Objective: The aim of this study was to investigate the relationship between exercise and gut Microbiome and to assess its possible causality.Methods: Using Mendelian randomization (MR) research methods, we collected genetic data from different populations, including genetic variants associated with relative abundance or presence of microbial taxa as instrumental variables. At the same time, we extracted results related to obesity and gut Microbiome from existing relevant studies and used inverse variance weighting (IVW), weighted median, and MR-Egger regression to assess the causal relationship between obesity and gut Microbiome. We plotted forest plots and scatter plots of the association between obesity and gut Microbiome.Results: Gut Microbiome was positively associated with obesity, and four bacterial genera (Akkermansia, RuminococcaceaeUCG011, Holdemania, and Intestinimonas) were associated with obesity according to inverse variance-weighted estimation in at least one MR method. Inverse variance weighted estimation showed that obesity was associated with obesity in Akkermansia (OR = 0.810, 95% CI 0.608–1.079, p = 0.04), RuminococcaceaeUCG011 (OR = 1.238, 95% CI 0. 511–2.999, p = 0.04), Holdemania Intestinimonas (OR = 1.214, 95% CI 1.002–1.470, p = 0.03), and Intestinimonas (OR = 0.747, 95% CI 0.514–1.086, p = 0.01) had a relevant effect. Obesity decreased the abundance of Akkermansia, Intestinimonas microbiome and increased the abundance of RuminococcaceaeUCG011, Holdemania microbiome.Conclusion: The results of this study, conducted using a two-sample Mendelian randomization method, suggest a causal relationship between obesity and intestinal microbiome. Obesity decreased the abundance of Akkermansia, Intestinimonas microbiome and increased the abundance of RuminococcaceaeUCG011, Holdemania microbiome. More randomized controlled trials are necessary to elucidate the protective effects of exercise on gut Microbiome and its unique protective mechanisms.
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- 2024
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9. Catalyst-free electrochemical SNAr of electron-rich fluoroarenes using carboxylic acids.
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Anzai Shi, Yaowen Liu, Ranran Zhang, Zile Zhu, and Youai Qiu
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ELECTROCHEMICAL analysis , *CATALYSTS , *AROMATIC fluorine compounds , *CARBOXYLIC acids , *ELECTRODES - Abstract
Herein, an electrochemically driven catalyst-free nucleophilic aromatic substitution (SNAr) of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported. A series of highly valuable ester derivatives were obtained in a direct and rapid way. This transformation features commercially available reagents and an exceptionally broad substrate scope with good functional group tolerance, using cheap and abundant electrodes and completed within a short reaction time. Gram-scale synthesis and complex biorelevant compounds ligation further highlighted the potential utility of the methodology. The mechanistic investigations and density functional theory (DFT) calculations verified the feasibility of the proposed pathway of this transformation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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