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One-way Acoustic Beam Splitter

Yifan Tang, Yifan Zhu, Bin Liang, Jing Yang, Jun Yang, Jianchun Cheng
2018 Scientific Reports  
As a key component of various acoustic systems, acoustic beam splitter (BS) finds important application in many scenarios, yet are conventionally based on the assumption that the acoustic waves propagate as easily when incident from either input or output side. It would therefore be intriguing, from the viewpoints of both science and technology, to break through this limit by realizing acoustic BSs supporting asymmetric transmission. Here we propose the concept of one-way acoustic BS capable of
more » ... splitting acoustic beam incident from the input port into multiple beams while effectively reducing the backward transmission from any of the output ports. Furthermore, our design enables flexibly adjusting the number and angle of output beams by blocking the unused line defects. The numerical results verify the theoretical predictions and demonstrate the phenomenon of one-way acoustic BS at the predesigned frequency. Our design with functionality and flexibility bridges the gap between acoustic diodes and BSs and may enable novel multi-functional devices with great application prospects in diverse fields such as acoustic integrated circuits and acoustic communication.
doi:10.1038/s41598-018-29579-0 pmid:30206365 pmcid:PMC6134148 fatcat:pb7xqxfm3zguzmocvypv2e37xe

Automated structure refinement of macromolecular assemblies from cryo-EM maps using Rosetta [article]

Ray Yu-Ruei Wang, Yifan Song, Benjamin Barad, Yifan Cheng, James Fraser, Frank DiMaio
2016 biorxiv/medrxiv   pre-print
Cryo-EM has revealed many challenging yet exciting macromolecular assemblies at near-atomic resolution (3-4.5 Angstrom), providing biological phenomena with molecular descriptions. However, at these resolutions accurately positioning individual atoms remains challenging and may be error-prone. Manually refining thousands of amino acids -- typical in a macromolecular assembly -- is tedious and time-consuming. We present an automated method that can improve the atomic details in models manually
more » ... ilt in near-atomic-resolution cryo-EM maps. Applying the method to three systems recently solved by cryo-EM, we are able to improve model geometry while maintaining or improving the fit-to-density. Backbone placement errors are automatically detected and corrected, and the refinement shows a large radius of convergence. The results demonstrate the method is amenable to structures with symmetry, of very large size, and containing RNA as well as covalently bound ligands. The method should streamline the cryo-EM structure determination process, providing accurate and unbiased atomic structure interpretation of such maps.
doi:10.1101/050286 fatcat:ovrcnpqizfd5dd4vxc6bzql2iq

Automated structure refinement of macromolecular assemblies from cryo-EM maps using Rosetta

Ray Yu-Ruei Wang, Yifan Song, Benjamin A Barad, Yifan Cheng, James S Fraser, Frank DiMaio
2016 eLife  
Acta crystallographica Section D, 814 Biological crystallography (2009) Marlovits TC, Cheng Y, Baker D: Atomic-accuracy models from 4.5-a 833 cryo-electron microscopy data with density-guided iterative  ... 
doi:10.7554/elife.17219 pmid:27669148 pmcid:PMC5115868 fatcat:hhag5tmqtnag3o4rf62xmli4bm

Integer colorings with forbidden rainbow sums [article]

Yangyang Cheng, Yifan Jing, Lina Li, Guanghui Wang, Wenling Zhou
2020 arXiv   pre-print
For a set of positive integers A ⊆ [n], an r-coloring of A is rainbow sum-free if it contains no rainbow Schur triple. In this paper we initiate the study of the rainbow Erdős-Rothchild problem in the context of sum-free sets, which asks for the subsets of [n] with the maximum number of rainbow sum-free r-colorings. We show that for r=3, the interval [n] is optimal, while for r≥8, the set [ n/2 , n] is optimal. We also prove a stability theorem for r≥4. The proofs rely on the hypergraph container method, and some ad-hoc stability analysis.
arXiv:2005.14384v1 fatcat:tvrcutixingqtpoe5aev5zsk2y

Cherry Tree Crown Extraction from Natural Orchard Images with Complex Backgrounds

Zhenzhen Cheng, Lijun Qi, Yifan Cheng
2021 Agriculture  
Most of all, Zhenzhen Cheng wants to thank her partner Yifan Cheng for the constant encouragement and support. Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/agriculture11050431 fatcat:eug5bmzffrg5zc5ku5kzufof7i

Interlacing Orchard Canopy Separation and Assessment using UAV Images

Zhenzhen Cheng, Lijun Qi, Yifan Cheng, Yalei Wu, Hao Zhang
2020 Remote Sensing  
Most of all, Zhenzhen Cheng wants to thank her partner Yifan Cheng for the constant encouragement and support. Conflicts of Interest: The authors declare no conflict of interest.  ... 
doi:10.3390/rs12050767 fatcat:bglqa2u3gnbyjojvzwzxtquqmm

Single-Particle Cryo-EM at Crystallographic Resolution

Yifan Cheng
2015 Cell  
Cryo-EM work in the Cheng laboratory is supported by grants from the NIH (R01GM098672, R01GM082893 and S10RR026814 to Y.C. and P50GM082250 to A.  ... 
doi:10.1016/j.cell.2015.03.049 pmid:25910205 pmcid:PMC4409662 fatcat:spbxpohhrfd2hg3w37xo3fsgve

Single Particle CryoEM of Integral Membrane Proteins

Yifan Cheng
2015 Biophysical Journal  
Cheng.  ...  supported by grants from the NIH (R01GM072804, R21AR063255, P41RR002250 and S10OD016279), the AHA (14RNT1980029) and the MDA (295138) 2518-Symp Single Particle CryoEM of Integral Membrane Proteins Yifan  ... 
doi:10.1016/j.bpj.2014.11.2729 fatcat:ljg26kqinbcgtbfefidzie5qgq

Allosteric Communication in the Dynein Motor Domain

Gira Bhabha, Hui-Chun Cheng, Nan Zhang, Arne Moeller, Maofu Liao, Jeffrey A. Speir, Yifan Cheng, Ronald D. Vale
2014 Cell  
Dyneins power microtubule motility using ringshaped, AAA-containing motor domains. Here, we report X-ray and electron microscopy (EM) structures of yeast dynein bound to different ATP analogs, which collectively provide insight into the roles of dynein's two major ATPase sites, AAA1 and AAA3, in the conformational change mechanism. ATP binding to AAA1 triggers a cascade of conformational changes that propagate to all six AAA domains and cause a large movement of the "linker," dynein's
more » ... element. In contrast to the role of AAA1 in driving motility, nucleotide transitions in AAA3 gate the transmission of conformational changes between AAA1 and the linker, suggesting that AAA3 acts as a regulatory switch. Further structural and mutational studies also uncover a role for the linker in regulating the catalytic cycle of AAA1. Together, these results reveal how dynein's two major ATPbinding sites initiate and modulate conformational changes in the motor domain during motility.
doi:10.1016/j.cell.2014.10.018 pmid:25417161 pmcid:PMC4269335 fatcat:wje4as5bznea7n4glscrypnqvy

How Cryo-EM Became so Hot

Yifan Cheng, Robert M. Glaeser, Eva Nogales
2017 Cell  
The Royal Swedish Academy of Sciences awarded the 2017 Nobel Prize for Chemistry to Jacques Dubochet, Joachim Frank, and Richard Henderson for "developing cryoelectron microscopy for the high-resolution structure determination of biomolecules in solution." Achieving this goal, which required innovation, persistence, and uncommon physical insight, has broadened horizons for structural studies in molecular and cell biology.
doi:10.1016/j.cell.2017.11.016 pmid:29195065 pmcid:PMC6186021 fatcat:ulmg62zj4jbifo6e4qpavw7dgu

Experimental Realization of Acoustic Chern Insulator [article]

Yifan Zhu, Yugui Peng, Xudong Fan, Jing Yang, Bin Liang, Xuefeng Zhu,, Jianchun Cheng
2018 arXiv   pre-print
Topological insulators are new states of matter in which the topological phase originates from symmetry breaking. Recently, time-reversal invariant topological insulators were demonstrated for classical wave systems, such as acoustic systems, but limited by inter-pseudo-spin or inter-valley backscattering. This challenge can be effectively overcome via breaking the time-reversal symmetry. Here, we report the first experimental realization of acoustic topological insulators with nonzero Chern
more » ... bers, viz., acoustic Chern insulator (ACI), by introducing an angular-momentum-biased resonator array with broken Lorentz reciprocity. High Q-factor resonance is leveraged to reduce the required speed of rotation. Experimental results show that the ACI featured with a stable and uniform metafluid flow bias supports one-way nonreciprocal transport of sound at the boundaries, which is topologically immune to the defect-induced scatterings. Our work opens up opportunities for exploring unique observable topological phases and developing practical nonreciprocal devices in acoustics.
arXiv:1801.07942v1 fatcat:r4dzju5o65aingh7mfudrf6pea

Decoupled Spatial-Temporal Attention Network for Skeleton-Based Action Recognition [article]

Lei Shi, Yifan Zhang, Jian Cheng, Hanqing Lu
2020 arXiv   pre-print
Dynamic skeletal data, represented as the 2D/3D coordinates of human joints, has been widely studied for human action recognition due to its high-level semantic information and environmental robustness. However, previous methods heavily rely on designing hand-crafted traversal rules or graph topologies to draw dependencies between the joints, which are limited in performance and generalizability. In this work, we present a novel decoupled spatial-temporal attention network(DSTA-Net) for
more » ... -based action recognition. It involves solely the attention blocks, allowing for modeling spatial-temporal dependencies between joints without the requirement of knowing their positions or mutual connections. Specifically, to meet the specific requirements of the skeletal data, three techniques are proposed for building attention blocks, namely, spatial-temporal attention decoupling, decoupled position encoding and spatial global regularization. Besides, from the data aspect, we introduce a skeletal data decoupling technique to emphasize the specific characteristics of space/time and different motion scales, resulting in a more comprehensive understanding of the human actions.To test the effectiveness of the proposed method, extensive experiments are conducted on four challenging datasets for skeleton-based gesture and action recognition, namely, SHREC, DHG, NTU-60 and NTU-120, where DSTA-Net achieves state-of-the-art performance on all of them.
arXiv:2007.03263v1 fatcat:f2ihxhz5ynfovcnkzrwcsqlnui

Mechanisms of Chromatin Remodeling Motors

Geeta Narlikar, John Leonard, Lisa Racki, Nariman Naber, Roger Cooke, Yifan Cheng
2012 Biophysical Journal  
Cheng.  ...  Sophistication and Complexity of Chemomechanical Control Linkages in Nucleic Acid 2174-Symp Mechanisms of Chromatin Remodeling Motors Geeta Narlikar, John Leonard, III, Lisa Racki, Nariman Naber, Roger Cooke, Yifan  ... 
doi:10.1016/j.bpj.2011.11.2343 fatcat:dkdpiumoirdhzamlaik7gqxeea

Skeleton-Based Action Recognition with Multi-Stream Adaptive Graph Convolutional Networks [article]

Lei Shi, Yifan Zhang, Jian Cheng, Hanqing LU
2019 arXiv   pre-print
Graph convolutional networks (GCNs), which generalize CNNs to more generic non-Euclidean structures, have achieved remarkable performance for skeleton-based action recognition. However, there still exist several issues in the previous GCN-based models. First, the topology of the graph is set heuristically and fixed over all the model layers and input data. This may not be suitable for the hierarchy of the GCN model and the diversity of the data in action recognition tasks. Second, the
more » ... er information of the skeleton data, i.e., the length and orientation of the bones, is rarely investigated, which is naturally more informative and discriminative for the human action recognition. In this work, we propose a novel multi-stream attention-enhanced adaptive graph convolutional neural network (MS-AAGCN) for skeleton-based action recognition. The graph topology in our model can be either uniformly or individually learned based on the input data in an end-to-end manner. This data-driven approach increases the flexibility of the model for graph construction and brings more generality to adapt to various data samples. Besides, the proposed adaptive graph convolutional layer is further enhanced by a spatial-temporal-channel attention module, which helps the model pay more attention to important joints, frames and features. Moreover, the information of both the joints and bones, together with their motion information, are simultaneously modeled in a multi-stream framework, which shows notable improvement for the recognition accuracy. Extensive experiments on the two large-scale datasets, NTU-RGBD and Kinetics-Skeleton, demonstrate that the performance of our model exceeds the state-of-the-art with a significant margin.
arXiv:1912.06971v1 fatcat:2hotk5vbqjb3riilvj3niv72ce

Mechanisms governing irritant-evoked activation and calcium modulation of TRPA1 [article]

Jianhua Zhao, John V. Lin King, Yifan Cheng, David Julius
2019 bioRxiv   pre-print
Acknowledgments We thank all members of the Julius and Cheng labs for thoughtprovoking discussion and critical reading of the manuscript.  ...  M., Cheng, Y. & Julius, D. Structural insights into TRPM8 inhibition and desensitization. Science 365, 1434-1440 (2019). Figures S1- S9 Fig S9 .  ...  ., Cheng, Y. & Julius, D. Structure of the TRPA1 ion channel suggests regulatory mechanisms. Nature 520, 511-517 (2015). 12 Hille, B. Ion channels of excitable membranes.  ... 
doi:10.1101/2019.12.26.888982 fatcat:5flarbybt5ewzflgujkq4t6lcu
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