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Publication Dynamics of Equilibrium Folding and Unfolding Transitions of Titin Immunoglobulin Domain under Constant Forces(American Chemical Society, 2015) Chen Hu; Yuan Guohua; RICKSEN SURYA WINARDHI; Yao Mingxi; Popa Ionel; Fernandez Julio M.; Yan Jie; MECHANOBIOLOGY INSTITUTEPublication Modulation of Manganite Nanofilm Properties Mediated by Strong Influence of Strontium Titanate Excitons(American Chemical Society, 2017-12-06) Yin, Xinmao; Tang, Chi Sin; Majidi, Muhammad Aziz; Ren, Peng; Wang, Le; Yang, Ping; Diao, Caozheng; Yu, Xiaojian; Breese, Mark B. H.; Wee, Andrew T. S.; Wang, Junling; Rusydi, Andrivo; PHYSICS; SINGAPORE SYNCHROTRON LIGHT SOURCEHole-doped perovskite manganites have attracted much attention because of their unique optical, electronic, and magnetic properties induced by the interplay between spin, charge, orbital, and lattice degrees of freedom. Here, a comprehensive investigation of the optical, electronic, and magnetic properties of La 0.7 Sr 0.3 MnO 3 thin films on SrTiO 3 (LSMO/STO) and other substrates is conducted using a combination of temperature-dependent transport, spectroscopic ellipsometry, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. A significant difference in the optical property of LSMO/STO that occurs even in thick (87.2 nm) LSMO/STO from that of LSMO on other substrates is discovered. Several excitonic features are observed in thin film nanostructure LSMO/STO at -4 eV, which could be attributed to the formation of anomalous charged excitonic complexes. On the basis of the spectral weight transfer analysis, anomalous excitonic effects from STO strengthen the electronic correlation in LSMO films. This results in the occurrence of optical spectral changes related to the intrinsic Mott-Hubbard properties in manganites. We find that while lattice strain from the substrate influences the optical properties of the LSMO thin films, the coexistence of strong electron-electron (e-e) and electron-hole (e-h) interactions which leads to the resonant excitonic effects from the substrate plays a much more significant role. Our result shows that the onset of anomalous excitonic dynamics in manganite oxides may potentially generate new approaches in manipulating exciton-based optoelectronic applications. © Copyright 2017 American Chemical Society.Publication Comparing patterns of taxonomic, functional and phylogenetic diversity in reef coral communities(Springer Verlag, 2018-09-01) Joy Wong Shu Yee; CHAN YONG KIT, SAMUEL; NG CHIN SOON LIONEL; TUN PHYU PHYU, KARENNE; Emily S Darling; Huang Danwei; BIOLOGICAL SCIENCESBiodiversity defines the variety of living organisms on this planet and is often quantified by the total number of species. However, species richness is insufficient in accounting for the differences in evolutionary history and the functions species contribute to the ecosystem. To address this shortcoming, phylogenetic diversity and functional diversity are increasingly being quantified and studied to inform ecological theory and conservation prioritisation. For scleractinian reef corals, congruence, mismatch and complementarity among different biodiversity components remain unknown, but recently available trait and phylogenetic data provide a robust test of these relationships. Here, we examine the taxonomic, functional and phylogenetic diversity of corals across a gradient of diversity in Singapore. Relationships among the biodiversity components at 25 reef sites are compared to identify patterns of mismatch or congruence for testing the precision of using one as a proxy for another. Furthermore, we examine community assembly of corals using null models derived from randomised community data. Our results show that correlations among biodiversity components are generally positive but weak, with species-dependent (non-abundance-weighted) metrics more strongly correlated with one another than species-independent (abundance-weighted) measures. No single biodiversity component could predict another precisely to be used as a reliable proxy for coral communities. Therefore, if trait diversity and evolutionary history were to be set as conservation targets, it is essential to maximise functional diversity and phylogenetic diversity explicitly when identifying areas or assemblages for management. Null models reveal the presence of more-than-expected similarities in trait combinations and evolutionary relationships among species in most reef communities. These findings suggest that environmental filtering under high levels of coastal development and sedimentation may be associated with coral community composition on Singapore’s reefs. Our approach provides new insights into the relationships between different components of coral diversity and has important applications for marine conservation planning.Publication Mixed-dish Recognition with Contextual Relation Networks(2019-10-21) Lixi Deng; Jingjing Chen; Qianru Sun; Xiangnan He; Sheng Tang; Zhaoyan Ming; Yongdong Zhang; Tat-Seng Chua; DEPARTMENT OF COMPUTER SCIENCEMixed dish is a food category that contains different dishes mixed in one plate, and is popular in Eastern and Southeast Asia. Recognizing individual dishes in a mixed dish image is important for health related applications, e.g. calculating the nutrition values. However, most existing methods that focus on single dish classification are not applicable to mixed-dish recognition. The new challenge in recognizing mixed-dish images are the complex ingredient combination and severe overlap among different dishes. In order to tackle these problems, we propose a novel approach called contextual relation networks (CR-Nets) that encodes the implicit and explicit contextual relations among multiple dishes using region-level features and label-level co-occurrence, respectively. This is inspired by the intuition that people are likely to choose dishes with common eating habits, e.g., with multiple nutrition but without repeating ingredients. In addition, we collect a large-scale dataset of mixed-dish images that contain 9, 254 mixed-dish images from 6 school canteens in Singapore. Extensive experiments on both our dataset and a smaller-scale public dataset validate that our CR-Nets can achieve top performance for localizing the dishes and recognizing their food categories. © 2019 Association for Computing Machinery.Publication Implementing Optogenetic Modulation in Mechanotransduction(American Physical Society, 2020-04-01) YU MIAO; LE SHIMIN; SAMUEL FARDELL HASTINGS BARNETT; GUO ZHENHUAN; Xueying Zhong; KANCHANAWONG,PAKORN; YAN JIE; BIOMEDICAL ENGINEERING; MECHANOBIOLOGY INSTITUTE; PHYSICSMolecular optogenetic switch systems are extensively employed as a powerful tool to spatially and temporally modulate a variety of signal transduction processes in cells. However, the applications of such systems in mechanotransduction processes where the mechanosensing proteins are subject to mechanical forces of several piconewtons are poorly explored. In order to apply molecular optogenetic switch systems to mechanobiological studies, it is crucial to understand their mechanical stabilities which have yet to be quantified. In this work, we quantify a frequently used molecular optogenetic switch, iLID-nano, which is an improved light-induced dimerization between LOV2-SsrA and SspB. Our results show that the iLID-nano system can withstand forces up to 10 pN for seconds to tens of seconds that decrease as the force increases. The mechanical stability of the system suggests that it can be employed to modulate mechanotransduction processes that involve similar force ranges. We demonstrate the use of this system to control talin-mediated cell spreading and migration. Together, we establish the physical basis for utilizing the iLID-nano system in the direct control of intramolecular force transmission in cells during mechanotransduction processes.Publication First Demonstration of Waveguide-Integrated Black Phosphorus Electro-Optic Modulator for Mid-Infrared Beyond 4 μm(2020-02-13) Li Huang; Bowei Dong; Yiming Ma; Chengkuo Lee; Kah-Wee Ang; ELECTRICAL AND COMPUTER ENGINEERINGWe demonstrate the first black phosphorus (BP) electro-optic modulator integrated with Si waveguide for the mid-infrared (MIR) spectrum from 3.85 to 4.1 μm. Optical properties of BP were effectively modulated by a vertical electric field from a top gate through Burstein-Moss and Franz-Keldysh effects. With a gate bias of -4 V, a modulation depth of ~5 dB was achieved with a small active footprint of merely 225 μm 2 . The modulation depth was observed to increase with decreasing light power. The results are promising for operations under weak-light condition with low-power consumption and compact footprint at room temperature. Our device lays a stepping stone towards realizing on-chip MIR systems for applications such as bio-sensing and environment monitoring.Publication A Modulation Strategy with Transformer Leakage Inductance Energy Management for a Three-Phase Matrix-based Isolated AC-DC Converter(2023-01-25) JAYDEEP SAHA; NAGA BRAHMENDRA YADAV GORLA; Panda, S.K.; ELECTRICAL AND COMPUTER ENGINEERINGPublication Artificial Synapses Based on Multiterminal Memtransistors for Neuromorphic Application(Wiley-VCH Verlag, 2019-04-22) Wang, Lin; Liao, Wugang; Wong, Swee Hang; Yu, Zhi Gen; Li, Sifan; Lim, Yee-Fun; Feng, Xuewei; Tan, Wee Chong; Huang, Xin; Chen, Li; Liu, Liang; Chen, Jingsheng; Gong, Xiao; Zhu, Chunxiang; Liu, Xinke; Zhang, Yong-Wei; Chi, Dongzhi; Ang, Koh-Wee; ELECTRICAL AND COMPUTER ENGINEERING; MATERIALS SCIENCE AND ENGINEERINGNeuromorphic computing, which emulates the biological neural systems could overcome the high-power consumption issue of conventional von-Neumann computing. State-of-the-art artificial synapses made of two-terminal memristors, however, show variability in filament formation and limited capacity due to their inherent single presynaptic input design. Here, a memtransistor-based arti?cial synapse is realized by integrating a memristor and selector transistor into a multiterminal device using monolayer polycrys-talline-MoS2 grown by a scalable chemical vapor deposition (CVD) process. Notably, the memtransistor offers both drain- and gate-tunable nonvolatile memory functions, which efficiently emulates the long-term potentiation/depression, spike-amplitude, and spike-timing-dependent plasticity of biological synapses. Moreover, the gate tunability function that is not achievable in two-terminal memristors, enables significant bipolar resistive states switching up to four orders-of-magnitude and high cycling endurance. First-principles calculations reveal a new resistive switching mechanism driven by the diffusion of double sulfur vacancy perpendicular to the MoS2 grain boundary, leading to a conducting switching path without the need for a filament forming process. The seamless integration of multiterminal memtransistors may offer another degree-of-freedom to tune the synaptic plasticity by a third gate terminal for enabling complex neuromorphic learning. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimPublication Shorter-is-Better: Venue Category Estimation from Micro-Video(Association for Computing Machinery, Inc, 2016-10-15) Jianglong Zhang; Liqiang Nie; Xiang Wang; Xiangnan He; Xianglin Huang; Tat-Seng Chua; DEPARTMENT OF COMPUTER SCIENCEAccording to our statistics on over 2 million micro-videos, only 1.22% of them are associated with venue information, which greatly hinders the location-oriented applications and personalized services. To alleviate this problem, we aim to label the bite-sized video clips with venue categories. It is, however, nontrivial due to three reasons: 1) no available benchmark dataset; 2) insufficient information, low quality, and information loss; and 3) complex relatedness among venue categories. Towards this end, we propose a scheme comprising of two components. In particular, we first crawl a representative set of micro-videos from Vine and extract a rich set of features from textual, visual and acoustic modalities. We then, in the second component, build a tree-guided multi-task multi-modal learning model to estimate the venue category for each unseen micro-video. This model is able to jointly learn a common space from multi-modalities and leverage the predefined Foursquare hierarchical structure to regularize the relatedness among venue categories. Extensive experiments have well-validated our model. As a side research contribution, we have released our data, codes and involved parameters. © 2016 ACM.Publication Identifying Emergent Research Trends by Key Authors and Phrases(Association for Computational Linguistics, 2018) Shenhao Jiang; Animesh Prasad; Min-Yen Kan; Kazunari Sugiyama; INST FOR APPLN OF LEARNING SCI & ED TECH; DEPARTMENT OF COMPUTER SCIENCE; ASIA RESEARCH INSTITUTEIdentifying emergent research trends is a key issue for both primary researchers as well as secondary research managers. Such processes can uncover the historical development of an area, and yield insight on developing topics. We propose an embedded trend detection framework for this task which incorporates our bijunctive hypothesis that important phrases are written by important authors within a field and vice versa. By ranking both author and phrase information in a multigraph, our method jointly determines key phrases and authoritative authors. We represent this intermediate output as phrasal embeddings, and feed this to a recurrent neural network (RNN) to compute trend scores that identify research trends. Over two large datasets of scientific articles, we demonstrate that our approach successfully detects past trends from the field, outperforming baselines based solely on text centrality or citation.