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NSFC/RGC Joint Research Scheme 2017/18 Supported Applications - Layman Summaries of Projects Funded in 2017/18 Exercise

Synthesis of Anisotropic Perovskite Nanocrystals with Polarized Emission for Light Emitting Diodes

Hong Kong Principal Investigator: Prof Andrey Rogach (City University of Hong Kong)
Mainland Principal Investigator: Prof Zhong Haizheng (Beijing Institute of Technology)

In the last few years, lead halide perovskites as a class of materials have attracted a great deal of interest for solar and other applications. Perovskites can be grown in solution as nanocrystals, and in this form they may offer considerable advantages for applications such as color display devices. Right from the outset perovskite QDs have shown very attractive performance: photoluminescence quantum yields have been as high as 90-95% whilst the emission spectral widths have been narrow, which is helpful for the rendering of saturated colors and in tri-color liquid crystal displays (LCDs) allows a wide color gamut to be covered. As an LCD back panel illumination source, perovskites could be driven either as down converters, illuminated themselves by short wavelength conventional LED arrays, or as directly driven LEDs in their own right. The later would be highly desirable for mobile applications as it will lead to thinner, lighter weight displays. An additional and critical performance metric for mobile and battery operated devices is the power efficiency of backlit displays. Since the LCD part of the displays requires polarized light, an inherently polarized back panel is highly desirable as it would allow all of the light output to be used rather than discarding over 50% of the emission by passing it through a sheet polarizer. Elongated, anisotropic nanocrystals can emit polarized light when they are aligned in parallel. The aim of this project is to bring all of the potential advantages of anisotropic perovskite nanocrystals together in order to demonstrate two classes of polarized back panel emitters – one based on down-conversion and the other based on direct electrical excitation. This will entail maximization of the polarization anisotropy ratio, both via growth of elongated QDs and subsequent alignment of the particle long axes in the back panel emitter structures, whilst simultaneously maintaining the high emission quantum yield and color purity of the materials.

Investigating the Role of Long-noncoding RNA Structures and Interactions in Human Cancer Cells

Hong Kong Principal Investigator: Dr Kwok Chun Kit (City University of Hong Kong)
Mainland Principal Investigator: Dr Zhang Cliff Qiangfeng (Tsinghua University)

Accumulating evidences have shown that lncRNAs play an important role in the development of cancer. The knowledge of lncRNA secondary structures and especially their functional structural elements and also the information of lncRNA interacting proteome are the two basis for further studies of the role of lncRNAs. On this basis, the interplay between lncRNA secondary structures and their interacting proteomes is the key to understanding the molecular mechanism of lncRNA functions and regulations in cancer.

In this collaborative project, we will develop new high-throughput techniques to probe transcriptome-wide lncRNA secondary structures and also G-quadruplexes in different cancer cell lines. We will design a new bioinformatics algorithm to reconstruct cell-specific lncRNA secondary structural models based on experimental data, and to identify a set of lncRNAs with secondary structural elements important in cancers through comparative analysis. We will then focus on some lncRNAs in this set, e.g., MALAT1, to experimentally characterize their interacting proteomes by using ChIRP-MS. We will analyze and validate the interplay of the secondary structures and the interacting proteomes of MALAT1 and other important lncRNAs in different cancer cell lines.

This collaborative project combines interdisciplinary experimental and computational approaches and integrates the two research groups' years of research experience in RNA structure and RNA-protein interactions. It uses and improves the cutting-edge techniques to study molecular mechanisms of lncRNA’s role in cancer. It will advance our understanding of lncRNAs in both basic and translational research.

L-lactate Release by Optogenetic Activation of Astrocytes Rescues Decision-making Deficit in Visceral Hypersensitive Rats

Hong Kong Principal Investigator: Prof Li Ying (City University of Hong Kong)
Mainland Principal Investigator: Prof Tu Jie (Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences)

The clinical connection between visceral pain and the increases in levels of anxiety, depression, as well as cognitive disorders, has long been recognized, however, these emotional and cognitive signs are far less studied than the sensory components of visceral pain. Human brain imaging studies have revealed anterior cingulate cortex (ACC) as a key brain target for mediating visceral pain-cognitive interactions. Recently, we characterized impairments of long-term potentiation (LTP) and spike-field coherence as key electrophysiological features associated with decision-making deficit in visceral hypersensitive (VH) state. Nonetheless, the underlying molecular mechanisms are poorly understood.

The brain requires continuous supply of oxygen and energy-yielding substrates involving glucose. A growing body of evidence suggests that L-lactate, byproduct of astrocytic glycolysis, plays a critical role in cognition processing. Astrocytes respond to all forms of CNS damage and disease by undergoing cellular, molecular and functional changes. Our preliminary data showed markedly reactive astrogliosis occurs in ACC in VH rats. We hypothesized that impaired L-lactate release casually involved in cognitive deficit in chronic visceral pain. We find failure of L-lactate release in an activity-dependent manner in chronic visceral pain. VH rats exhibited significant lower lactate level immediately after the cognitive behavioral task (rat gambling task RGT). Next, exogenous L-lactate infusion into ACC repairs the impairments of LTP and decision-making performance in VH rats.

Optogenetics can be used to control activity of specifically interested cells by light stimulation. We showed endogenous L-lactate released by optogenetic activating astrocytes rescues the visceral pain related decision-making deficit. Multiple-channel electrophysiological recordings revealed that activation of astrocytes facilitates spike-field coherence in the ACC of VH rats through lactate signaling pathway. Astrocytes neuron metabolic coupling would underscore the importance of functionally connecting these two cell types subserving brain cognitive functions, e.g. decision making. These findings provide new insights into cognitive treatment in clinical chronic visceral pain management.

Comprehensive Morphology Studies of Organic Solar Cell with Non-fullerene Acceptors

Hong Kong Principal Investigator: Prof Lu Xinhui (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Zhan Xiaowei (Peking University)

Non-fullerene acceptors, which are emerging as replacements for conventional fullerene derivatives, offer complementary absorption spectra to those of donor materials, adjustable energy levels, and batch-to-batch reproducibility. These characteristics have recently led the power conversion efficiency (PCE) of organic solar cells (OSCs) to exceed 12%. Despite the aggressive pursuit of PCE and the relentless development of new types of non-fullerene acceptors, few efforts have been devoted to systematic studies of the bulk heterojunction morphology of this system, which is known to be critical to the device performance of OSCs.

Multiphase molecular aggregation, morphology control, and precise characterization are challenging issues in non-fullerene OSCs for the following reasons: (1) unlike a fullerene derivative, a non-fullerene acceptor does not have a spherical geometry, and accordingly the aggregation and morphology are more difficult to control; (2) the co-planarity of the non-fullerene acceptor is relatively higher, which yields higher degrees of self-assembly and crystallinity and possibly an excessively large phase separation domain size; and (3) the lack of electron density contrast between the non-fullerene acceptor and donor materials will impose more difficulties on morphology characterization.

In this project, we will combine the strengths of both the PKU team regarding acceptor synthesis and device fabrication and the CUHK team regarding morphology characterization. We will design and synthesize high-performance planar fused-ring electron acceptor materials. We propose to conduct comprehensive morphology studies of OSCs with purposely designed non-fullerene acceptors using state-of-the-art scattering techniques such as grazing incidence wide-angle X-ray scattering (GIWAXS), grazing incidence small-angle X-ray scattering (GISAXS), resonance soft X-ray scattering (R-SoXS), and neutron scattering. The morphology understandings gained herein will allow us to control aggregation and morphology via molecular engineering and processing engineering and to fabricate high-efficiency non-fullerene OSCs.

We believe that our synergistic research will provide interactive guidance to both material synthesis and morphology control and lead to a fundamental understanding of the processing-morphology–device performance relationship, which will subsequently contribute to the development of OSCs for real-life applications.

Identification of New Susceptibility and Disease-causing Genes in the Pathogenesis and Prediction of Thyroid Associated Orbitopathy (TAO)

Hong Kong Principal Investigator: Dr Chong Kelvin Kam-lung (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Zhou Huifang (Shanghai Jiao Tong University)

Thyroid-associated ophthalmopathy (TAO) is an autoimmune orbital disease with the highest prevalence worldwide, which seriously impacting on the visual function and facial appearance. TAO causes eye-related dysfunction, discomfort, deformities and significantly decreases quality-of-life. Evidence suggests environmental triggers activate the immune system in genetically susceptible individuals leading to inflammation, swelling, and scarring of the fat and muscle tissues around the eyes. However, treatments available are limited by the incomplete understanding of the underlying mechanisms.

In our previous research, we have identified 5 susceptibility genes of TAO, including Cytotoxic lymphocyte antigen 4 (CTLA4), which is involved in the regulation of regulatory T cell (Treg) functions. We recently demonstrated helper-17 T lymphocytes (Th17) involvement in orbital inflammation and fibrosis. However, the imbalance of Th17/Treg, implicated in other autoimmune diseases, has not been investigated in TAO.

In this collaborative proposal, the two leading TAO centers will jointly examine existing large samples of sporadic (Shanghai, Hong Kong) and familial (Hong Kong) TAO patients using next-generation techniques by whole genome and exome sequencing. We will further identify those new susceptibilities and disease-causing genes with new samples (Shanghai and Hong Kong) to provide, for the first time, a comprehensive genetic map of TAO in Chinese Han Chinese.

We found that the single-nucleotide polymorphism (SNP) change in CTLA-4 altered the amino acid properties and disrupted the alpha helix structure of its signal peptide, leading to CTLA-4 dysfunction. We will study genotype of all risk alleles in CTLA-4 with protein transcription and expression in circulating blood cells from healthy, Graves' Disease (GD) and TAO subjects. Comparing context (basal and simulated) and cell-type specific (particularly for Th17 and Treg) expression differences will translate the genetic variant of CTLA-4 to Th17/Treg imbalance with relevance to TAO.

Hong Kong team will develop a longitudinal TAO registry to construct the first genotype-phenotype model which will be validated on new patients recruited and followed during the study period (Shanghai and Hong Kong).

Our results will generate new biomarkers, a functional platform and a prediction model for TAO. The information will not only help clinicians in prioritizing care but also provide scientists molecular targets to develop personalized treatments.

A Novel Robotic System to Facilitate NOTES Procedures with VR Augmentation

Hong Kong Principal Investigator: Prof Meng Max Qing-hu (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Liu Xiaoping (Beijing Jiaotong University)

Natural orifice transluminal endoscopic surgery (NOTES) is the latest MIS paradigm in which the access to abdominal cavity is gained via body’s natural orifice such as mouth, vagina and anus. This new approach completely eliminates abdominal wall incision and thus benefits the patients in several aspects such as less postoperative complications and improved cosmetic results. This project proposes to deal with some key issues about NOTES surgical devices and surgical navigation, providing new solutions to these existing problems. For this purpose, the main research tasks include:

1) Construction of surgical workspace by abdominal wall scaffolding;
2) Development of a modular NOTES robotic system;
3) Development of an adaptive control strategy for multiple robotic modules;
4) Deformable tissue 3D visualization and biomechanical deformation modeling;
5) Surgical planning and registration on deformable tissue; and
6) Development of new VR/AR-based surgical navigation methods, which based on pre- and intra-operative images and intra-operative tracking data;
7) Experimental validations by ex-vivo trials.

The success of this project will firstly provide patients with a safer alternative to the artificial pneumoperitoneum to create a stable surgical workspace inside abdominal cavity. Secondly, this project will provide surgeons with an advanced robotic surgical device for NOTES procedures. Compared to human, robotic system can provide more accurate and robust performances, and help standardize surgery to be independent of surgeon experience. Thirdly, the proposed control system will enable intuitive usage and smooth manipulation during the operation. At last, the application of augmented reality (AR) and virtual reality (VR) technologies in the surgical planning and navigation will tremendously enhance the surgeons’ experience and operating accuracy. Additionally, this project will also help the widespread application of this new surgical paradigm with dedicated devices and user-friendly software interface, thus benefits more patients in need.

Highly Efficient Catalysts for the Abatement of Both Diesel Soot and NOx Emissions from Ships

Hong Kong Principal Investigator: Prof Chen Yongsheng (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Zhao Zhen (Shenyang Normal University)

This proposal aims to develop highly efficient catalysts for the abatement of both diesel soot and NOx emissions from ships in order to improve air quality in big coastal cities such as Hong Kong. The Hong Kong Air Pollutant Emission Inventory for Year 2015 complied by the Environmental Protection Department (EPD) shows that the proportions of the nitrogen oxides (NOx, a precursor for smog) and respirable suspended particulates (RSP or PM10) emissions by navigation or ships are 37% and 34%, respectively, and ships have become the top contributor to these two pollutants among all sources. Selective catalytic reduction (SCR) is the most effective NOx abatement technology on the market to meet the stringent regulations on NOx emissions, and particulate matter (PM) treatment technologies include diesel particulate filter (DPF), diesel oxidation catalyst (DOC) and continuous regeneration trap (CRT). These technologies have been applied separately to reduce NOx and PM emissions from automobiles. In terms of ship emissions control, it is more challenging as the diesel fuels used in ships are of lower quality with much higher sulfur content. Consequently, sulfur poisoning leading to deactivation of SCR catalyst is more severe. Thus, the technical goal of this proposal is to develop catalysts that will possess high SCR activity and high sulfur tolerance as well as high soot oxidation capability. This will minimize or eliminate the needs for a separate soot treatment component. We will design three-dimensionally ordered macroporous (3DOM) TiO2-supported vanadium oxide-based catalysts with high sulfur tolerance for the efficient removal of soot and NOx. Specially, they will have macropores to allow efficient soot diffusion. We will also study the controlling factors for the synthesis and catalytic activity of these catalysts including composition, morphology, crystal structure of TiO2 support, dispersion of the active vanadia component, and the interactions between vanadia and the TiO2 support. Multiple materials characterization techniques will be employed to investigate the catalyst active sites and deactivation mechanisms. The fundamental understanding of the catalyst structure-performance relationship will help us identify the key elements in developing and synthesize highly efficient catalysts for the abatement of both diesel soot and NOx emissions from ships. If successful, new technology developed out of the proposed research will greatly improve the way NOx and soot emissions are abated and help improve the air quality in coastal cities worldwide.

Mechanisms by Which Brassinoteroids Regulate Plant Photomorphorgenesis Through GATA and MYB Transcription Factors

Hong Kong Principal Investigator: Prof He Junxian (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Lin Wenhui (Shanghai Jiao Tong University)

The aim of this project is to study the mechanisms by which the steroidal hormones brassinosteroids (BRs) regulate plant photomorphogenesis through the GATA and MYB transcription factors from Arabidopsis and rice.

 For plants, light is not only an energy source of photosynthesis, but also an important environmental signal. Light influences plant life cycle, including seed germination, seedling photomorphogenesis, phase transition and senescence. Before exposure to light, dark-grown seedlings undergo a named skotomorphogenesis process after germination. The hypocotyls elongate firstly, and apical hooks form to protect shoot apical meristems. Upon exposure to light, light-grown seedlings undergo a named photomorphogenesis process. They exhibit shortened hypocotyls, opened and expanded cotyledons with differentiated chloroplasts, and acquire the ability to carry out photosynthesis.

Several phytohormones are involved in regulation of plant skotomorphogenesis and photomorphogenesis. For example, brassinosteroids (BRs) have been implicated in these processes because the BR-deficient and insensitive mutants show typical photomorphogenic phenotypes even in darkness. However, how BRs regulate various photomorphogenic processes are currently not well known. We have previously reported that the Arabidopsis GATA2 transcription factor (AtGATA2) acts as an integrator of light and BR signals in regulating photomorphogenesis and is a direct target of the BR-regulated transcription factor BZR1 (Luo and Lin et al., 2010) and recently we found that OsGATA7, a rice homolog of AtGATA2, is involved in regulation of coleoptile growth in rice. In addition, AtMYB56 and OsMYBR2R3-1, a pair of MYB transcription factors from Arabidopsis and rice, were also found to regulate seedling photomorphogenesis and they function oppositely to GATAs. These findings suggest that OsGATA7, AtMYB56 and OsMYBR2R3-1 might act as new mediators of BR-regulated plant photomorphogenesis. However, how these new factors mediate BR-regulated photomorphogenesis remains to be understood.

This project aims to study the functions of these GATA and MYB factors in mediating BR- and light-regulated photomorphogenesis in both rice and Arabidopsis plants. We believe that the results from this project will lead to identification of new regulator(s) of plant growth and development and help answer two important questions: (1) what is the transcriptional framework that mediates BR- and light-regulated photomorphogenesis? (2) What are the similarities and differences in mechanisms of photomorphogenesis regulation in dicotyledon (Arabidopsis) and monocotyledon (rice) plants?

Construction of a Long Cycle-life Na-O2 Battery and Study of its Reaction Mechanism

Hong Kong Principal Investigator: Prof Chan Kwong Yu (The University of Hong Kong)
Mainland Principal Investigator: Prof Li Fujun (Nankai University)

Massive storage of electricity generated from intermittent renewable sources are needed for sustainable development. Scientists need to look beyond lithium ion batteries widely used in mobile phones and extent electric vehicles. This collaborative project aims to develop long cycle-life sodium-air batteries which are safe, low costs, and sustainable. The critical components of anode and cathode will be constructed with advanced multi-scale structured composite materials. There will be innovations in synthesis, configuration of electrochemical cells, and materials characterization in situ of electrochemical reactions. There are challenges in understanding competing redox reactions occurring in the bulk and at phase boundaries. Solid-electrolyte interface has been a limitation to various types of high energy density batteries, notably the lithium ion battery. Our investigations on sodium anode electrolyte interface using advanced in situ characterizations can reveal molecular phenomena that are general and applicable to other heterogeneous solid-liquid reactions. The proposed techniques of in situ DEMS, in situ Raman, and in situ XRD are state-of-the-art instrumentation, particularly for electrochemical

Microscopic studies of polymorphic structured transition-metal dichalcogenide epifilms: defects, domain boundaries and interlayer coupling

Hong Kong Principal Investigator: Prof Xie Maohai (The University of Hong Kong)
Mainland Principal Investigator: Prof Jin Chuanhong (Zhejiang University)

Silicon based microelectronics is faced with the challenge of further miniaturization of functional devices in integrated circuits. New device architectures or new materials are imminently needed in order to meet the ever-shrinking device demand as projected by the Moore’s law. An effective approach has been suggested to use a single atomic-layer, also called two-dimensional (2D), materials in such devices. Transition-metal dichalcogenides (TMDs) are a family of 2D semiconductors that hold such promises that have been extensively studied in recent years. Many unexpected and attractive properties have been discovered, yet the underlying physics requires further investigations. An important issue of TMD single-layer samples is defects and various microstructures that will affect strongly the properties of the materials. In this project, we shall carry out a comparative study on the microstructures and electronic properties of TMD layers. We shall perform controlled growth for varying defects followed by microscopic studies by combinational scanning tunneling microscopy and transmission electron microscopy methods. We will fabricate TMD nanostructures and characterize their properties. We hope to generate results that can be of great scientific and reference values for engineering TMDs for different application purposes.

Realization of 2D spin-orbit coupling of fermionic ytterbium atoms in optical lattices

Hong Kong Principal Investigator: Prof Jo Gyu-Boong (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Liu Xiong-Jun (Peking University)

The search for topological phases of matter has become a very important pursuit in physics over the past decade. Spin-orbit-coupling (SOC), one of the fundamental ingredients leading to topological phases in materials, has been also synthesized for ultracold atoms for the purposes of quantum simulation of such matter. To date, however, two-dimensional (2D) spin-orbit-couplings have only been realized in lattices for bosons and not for fermionic atoms, which are the natural counterpart of electrons in solids. Here, we propose the realization of 2D spin-orbit-coupling for ultracold fermions in an optical lattice, in which a novel topological phase is expected to exist. Our preliminary results demonstrate a novel method to implement spin-orbit coupling in a one-dimensional (1D) lattice dressed by Raman potential. We will apply a similar scheme to the 2D lattice system for ytterbium fermions.

We will reveal a novel type of topological phase using 2D spin-orbit coupled fermions in a lattice. For example, we shall explore a symmetry-protected topological (SPT) phase protected by appropriate symmetries, whose concept originates in the discovery of time-reversal invariant topological insulators. Our synthetic system with 1D/2D SOC will provide important fundamental insight into SPT phases, since only a small portion of theoretically predicted SPT phases have been observed in solid-state materials mainly due to the complicated and uncontrollable environment within solid-state materials.

In this project, we will expand our capability to explore a topological phase with ultracold fermions, and we propose (1) novel schemes for realizing 1D/2D spin-orbit coupling for ultracold atoms in an optical lattice, (2) the experimental realization of a 1D/2D spin-orbit-coupled lattice, and (3) the revelation of non-trivial topological phases with ultracold fermions.

Gene fusion study in tumor evolution and precision oncology of glioma

Hong Kong Principal Investigator: Prof Wang Jiguang (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Jiang Tao (Beijing Neurosurgical Institute)

Glioma is the most common and lethal tumor in central nervous system. Because of the heterogeneity of the tumor, the postoperative radiotherapy and chemotherapy is ineffective and the overall survival is poor. Recent studies have shown that fusion genes can serve as a biomarker for tumor classification and a target for tailored therapy. The FGFR3-TACC3 and PTPRZ1-MET fusion genes, which can define specific malignant subgroups, have been identified and validated in our previous study. The corresponding inhibitors have achieved significant tumor suppressive effect and have entered the clinical trials. The aim of this study is to screen and validate the fusion gene that drive glioma progression by detecting the transcriptional data of gliomas. Meanwhile, we aim to constructed a spatiotemporal evolutionary model of gliomas with fusion gene and gene mutation, and explained the heterogeneity of tumor after treatment. Finally, small molecular compounds that interact with the fusion genes will be screened and validated by in vitro and in vivo experiments to form an effective individualized treatment regimen. Our research will reveal the progression and evolution of glioma, which will promote the accurate classification, as well as the establishment and application of individualized diagnosis and treatment system.

A multi-functional graphene cross-linked 3D hydrogel for nerve tissue engineering and in-situ neuron screening

Hong Kong Principal Investigator: Prof Luo Zhengtang (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Xu Feng (Xi'an Jiaotong University)

Development a multi-functional hydrogel biosensor platform that allows simultaneous electrical stimulation, electrical and fluorescence recording of neuronal activities has a major impact on the understanding of the nervous system and provide insight into its possible repair and regeneration, which may eventually lead to the treatment of neural diseases such as deafness, paralysis, Parkinson's disease, etc. This platform take advantage of the excellent mechanical strength and electrically conductivity of graphene and the tissue-like biodegradable property of hydrogels to mimic the natural neural cell microenvironment for neural tissue engineering as well as neural activity recording. Fluorescent protein sensors will also be incorporated into the graphene-based hydrogel platform to enable real-time detection. The broad impact of our studies is the enhancement of partnerships with biological, clinical and materials scientists, which will allow a wide variety of regenerative biomedical applications of these hydrogel structures. This project will provide interdisciplinary learning opportunities for both postgraduate and undergraduate students through research collaboration.

Manipulating Light Using Non-Hermitian Photonic Crystals: Theory and Experiment

Hong Kong Principal Investigator: Prof Chan Che Ting (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Dong Jian Wen (Sun Yat-Sen University)

The information age is enabled by photonics, which involves the generation, transmission and detection of light. The control of the flow of light is hence of crucial importance in driving the economy of the 21st century, which relies on information transfer. While the field of photonics has witnessed rapid development in the past few decades, it is fair to say that it has not yet reached the same level of maturity as electronics has and new ideas are needed to improve the functionality of photonic components if we wish to control light as well as we are able to control the flow of electrons in circuits.

In order to improve the control of light, we propose to investigate the new physics associated with the so-called "non-Hermitian" photonic crystals. Traditional optical elements such as a lens, which is made of glass and has a curved surface, rely on two degrees of freedom to manipulate light: refractive index and shape. The shape of the lens, which is curved, and the refractive index of glass, which is higher than that of air, together enable the bending of light, leading to many optical instruments from microscopes to telescopes. However, such traditional optical elements are too bulky for many photonics application and the light bending power is not strong enough for many advanced applications.

Modern optical materials such as photonic crystals have more than one constituent material and have complex man-made internal structures. Such additional complexity offers extra degrees of freedom to optimize light manipulation, and photonic crystals have better light bending power and a smaller form factor and hence can manipulate light better than natural materials (such as glass). Today, most photonic crystals are made of materials of minimal loss and are called "Hermitian" photonic crystals, meaning that they neither give nor take energy from the light signal traveling inside the crystal. If we can add different amounts of loss/gain into the photonic crystal and at different locations of our choice, meaning that we can remove or add energy to the light beam at different points inside the optical component, we can amplify the light signal and make it travel longer distances. More importantly, light can be controlled by “non-Hermitian” photonic crystals in ways that cannot be realized in passive Hermitian photonic crystals with no loss or gain. This proposed project will generate new concepts and new phenomena that offer new functionalities to broaden the application scope of photonics technology.

Single Atom Based Low Platinum Nano Electrocatalysts: Rational Design, Synthesis, Characterization and Their Applications in Fuel Cells

Hong Kong Principal Investigator: Dr Shao Minhua (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Dr Wei Zidong (Chongqing University)

Proton exchange membrane fuel cells (PEMFCs) are clean energy conversion devices that have attracted significant attention for potential use in electric vehicles. The high cost of platinum (Pt)-based electrocatalysts for oxygen reduction reactions (ORRs) in the cathode of PEMFCs has hindered its widespread adoption. This proposal aims to develop a novel class of catalyst consisting of single-atom Pt, Fe and N doped carbon structures in collaboration with Chongqing University. In such a material, Pt and Fe atoms will be uniformly dispersed in carbon without forming other compounds that are less active in ORRs. The density of active sites will be significantly increased as a result. These catalysts are expected to enhance both the stability and ORR activity of carbon-based NPM catalysts

Investigating the Vesicular Dynamics in Inhibitory Synapses using Cryo Correlative Light and Electron Microscopy (CryoCLEM) and Real-Time Three-dimensional Nanometer-accuracy Tracking Microscope

Hong Kong Principal Investigator: Prof Park Hyokeun (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Bi Guoqiang (University of Science and Technology of China)

A number of neurological disorders are associated with an imbalance between excitation and inhibition in the central nervous system, including autism spectrum disorder (ASD), epilepsy, and schizophrenia. In the United States, more than 1% of all children have ASD. Despite their high prevalence, relatively few options are available for prevention and/or treatment of these diseases.

The balance between excitation and inhibition also plays an important role in processing cognitive tasks, including learning and memory. Neurons can excite or inhibit other neurons by releasing excitatory or inhibitory neurotransmitters, and extensive research regarding excitatory synapses has provided a relatively clear understanding of synaptic transmission and synaptic plasticity in learning and memory.

In contrast, far less research has focused on inhibitory synapses, despite recent studies that showed the importance of these synapses. Plasticity of inhibitory synapses is caused by a change in either the release properties of inhibitory vesicles or the properties of postsynaptic receptors. Moreover, specific proteins have been identified in inhibitory synapses, suggesting the presence of unique release machinery. Nevertheless, the dynamic properties of inhibitory vesicles that underlies their release of neurotransmitters remain poorly understood.

We recently developed high-resolution microscopes to study the organization and dynamics of synaptic vesicles. Specifically, we built a real-time three-dimensional (3D) microscope with nanometer-resolution tracking and used this system to monitor individual inhibitory vesicles in live neurons. In addition, the Bi lab have visualized the shapes and localization of individual synaptic vesicles and organelles in both excitatory and inhibitory synapses at high resolution using cryo-correlative light and electron microscopy (cryoCLEM). Based on our preliminary studies, we propose a collaborative team project to investigate the localization and movement of recycled inhibitory vesicles.

We will test our working hypothesis that vesicle dynamics differ fundamentally between inhibitory and excitatory synapses using two complementary techniques, namely real-time 3D tracking of individual inhibitory vesicles in live neurons (at HKUST) and high-resolution cryo-electron microscopy of inhibitory vesicles in fixed neurons (at USTC). Thus, we will systematically examine the spatial distribution and dynamics of recycling inhibitory vesicles. We will also investigate the distribution and movement of inhibitory vesicles undergoing spontaneous release.

Our results will shed new light on how the vesicular dynamics of inhibitory synapses contribute to the delicate and essential balance between excitation and inhibition. Our findings will also help identify new therapeutic targets and help researchers develop new strategies for treating neurological disorders caused by an imbalance between excitation and inhibition.

Cryo-EM Study of Origin Recognition Complexes Bound with Origin DNA

Hong Kong Principal Investigator: Prof Tye Bik Kwoon (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Gao Ning (Peking University)

Eukaryotic DNA replication is initiated from multiple sites known as replication origins along each chromosome. In the budding yeast Saccharomyces cerevisiae, the hetero-hexameric origin recognition complex (ORC) recognizes and binds to replication origin in an ATP dependent manner. The DNA-bound ORC recruits Cdc6, which in turn serves as a platform to load MCM2-7 replicative helicases with the help of Cdt1 onto origin DNA. ORC is highly conserved in function and structure from yeast to human but diverges in DNA binding specificity. The underlying mechanism of this divergence remains elusive. Furthermore, the molecular functions of individual ORC subunits in engaging with origin DNA to promote replication initiation are not well understood. In this collaborative NSFC/RGC research we propose to investigate the structures of the ORCs bound to origin DNA from both yeast and human using cryo electron microscopy. The outcomes of this research are expected to reveal many of the detailed molecular mechanisms of the ORC in both origin selection and helicase loading.

The study of cyclic codes based on nonlinear cryptographical functions

Hong Kong Principal Investigator: Dr Xiong Maosheng (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Zeng Xiangyong (Hubei University )

Cyclic codes are important in coding theory. They have a wide range of applications in the data storage systems, communication systems, consumer electronics products, and etc since their algebraic structure can be analyzed and the cycle structure is easy for hardware implement. How to construct cyclic codes with desired properties to meet the demands of practical systems remains an important research topic. This project mainly studies cyclic codes based on nonlinear cryptographic functions. It aims to explore new methods of constructing optimal or almost optimal cyclic codes by applying mathematical tools such as algebra and number theory and to find new methods for computing the weight distribution of cyclic codes with two or more zeros. Meanwhile this project will also study the relation between the cryptographic properties of nonlinear functions and the properties of cyclic codes. The purpose of this project is to build a bridge between nonlinear cryptographic functions and cyclic codes, to propose new methods for constructing good cyclic codes, to explore certain open problems about the correlation distribution between an m-sequence and its decimation sequence, and to establish new methods for studying nonlinear cryptographic functions from the view of coding theory. These can provide many more cyclic codes with various parameters and desired properties, and may have important theoretical and practical significance for developing new methods and techniques in the design and analysis of nonlinear cryptographic functions.

The role of phospholipid signaling in microglia colonization and small chemical compound screening in zebrafish

Hong Kong Principal Investigator: Prof Wen Zilong (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Zhang Wenqing (Southern Medical University)

Microglia are a subtype of macrophages that reside and function in the central nervous system (CNS). Because their macrophage characteristics, it has been thought for a long time that microglia predominantly act as immune cells to remove cellular debris and pathogenic invaders in the CNS. However, recent studies have revealed that, in addition to functioning as scavengers to cellular debris and invaded pathogens, they are also actively involved in the regulation of neurogenesis and neural function. Despite these progresses, how microglia precursors – peripheral macrophages, which are born in peripheral hematopoietic tissues, migrate from their birthplace to the CNS and subsequently differentiate into CNS-resident microglia remains poorly defined. Using zebrafish as a model organism, we have shown that the colonization of the brain by peripheral macrophages is regulated at least in part by neuronal cell death through releasing lysophosphatidylcholine (LPC). Intriguingly, we recently found that direct injection of lysophosphatidic acid (LPA), a pleiotropic lipid molecule with potent effects on cell growth and cell motility, into the fish brain leads to a significant increase of the number of microglia in the brain, suggesting that LPA might be another molecule mediating microglia colonization. In this proposal, we will elucidate the role of LPA and its cognate receptors in microglia colonization. In addition, we will conduct a chemical screening to identify small compounds interfering with microglia brain colonization. We believe that successful completion of the proposed study will contribute significantly to our understanding of the cellular and molecular basis underlying the establishment of microglia in the CNS.

Study on the Mechanism and Application of Energy Transfer in the Nonlinear Self-excited System for 10 MW Level Wind Turbine System

Hong Kong Principal Investigator: Dr Zhu Songye (The Hong Kong Polytechnic University)
Mainland Principal Investigator: Dr Ke Shitang (Nanjing University of Aeronautics and Astronautics (NUAA))

Wind energy, as an important renewable energy source, plays an increasingly important role in future power supply. The cumulative installed capacity of wind power in China has reached 176 GW, which currently ranks first in the world. Furthermore, the China Wind Energy Development Roadmap has officially announced its goal to achieve a wind power installed capacity of 1,000 GW and to contribute 17% of the total national power consumption by 2050. In particular, research and development on super-large-scale onshore/offshore horizontal axis wind turbines (HAWTs) (8-10MW) is recognized as a major challenging task to satisfy the rapidly growing trend of the wind power industry in China.

The increasing size or slenderness of HAWTs does not only reduce the stiffness and frequency of wind turbine structures, but also makes HAWTs exhibit apparent nonlinear behavior under unsteady aerodynamic excitations. All these factors make large-scale HAWTs vulnerable to excessive wind-induced vibrations, as evidenced by the frequent damage or collapse of wind turbines. Post-disaster reconnaissance shows that nonlinear vibrations are among the major causes of wind farm damage.

Nonlinear vibrations are frequently associated with the coupling of internal and external resonances, which enables energy transfer among different vibration modes and produces self-excited high-order harmonic vibrations. This phenomenon cannot be explained by the classical Greenberg aerodynamic model. The unexpected self-excitation of high-order vibration modes with apparent coupling and time-delay features has been observed in several previous studies on large-scale HAWTs. A pilot study conducted by the applicants also showed that nonlinear impact on the vibration response of large-scale HAWTs (>1.5 MW) was considerably higher than that on its small-scale counterparts. To date, investigation on the internal resonance of super-large-scale HAWTs, as well as its corresponding vibration impact and mitigation, has rarely been reported in the literature. Nevertheless, the significance of such investigation is being gradually recognized.

To fill in the existing knowledge gap, this project aims to systematically investigate the wind-induced nonlinear vibrations of super-large-scale HAWTs through a combination of wind tunnel experiment, numerical simulations, and analytical study. The research team has gained rich expertise in large-scale wind turbines, aerodynamics and structural vibration control. A 10MW super-large-scale HAWT prototype, which was previously developed by the applicants, will be employed as the research object in this project. The complex mechanism of the nonlinear vibrations of the 10MW HAWT, which include self-excitation, internal resonance, and energy transfer among modes, will be systematically addressed in this project. Subsequently, ad hoc vibration mitigation strategies for large-scale HAWTs will be explored by particularly considering nonlinear aeroelastic response and internal resonance. The outcome of this project will provide useful knowledge to the research and development of next-generation super-large-scale HAWTs.

Investigations on Two-dimensional Layered Materials with Strong Interlayer Coupling

Hong Kong Principal Investigator: Dr Chai Yang (The Hong Kong Polytechnic University)
Mainland Principal Investigator: Prof Ji Wei (Renmin University of China)

Two-dimensional (2D) materials possess unique physical properties that are absent in bulk counterpart. The interlayer coupling of 2D materials is generally regarded as weak Van der Waals interaction, and has negligible influence on their physical properties. Recently, it was found that some 2D materials, e.g., black phosphorus, PtS2 and PtSe2, have exceptional strong interlayer coupling. It has been shown with strong layer-dependent physical properties, such as, bandstructures, lattice constant, and vibration properties. This strong layer-dependence is a new dimension to tune the properties of materials, and can be employed to design new devices structures. However, the key factors for determining the interlayer coupling are so far yet to be clearly revealed. It is still unclear any other 2D materials beyond BP, PtS2, PtSe2 belong to this category with strong interlayer coupling. It is a fundamental interest to investigate the physical properties of monolayers, few-layers and heterojunctions and the device performance constructed with these 2D materials. This project aims to carry out experimental and theoretical investigations on these 2D materials with strong interlayer coupling. We start from revealing the key factors governing interlayer couplings of 2D materials, and find parameters to classify them. Based on these understandings, new members of the materials with strong interlayer coupling will be predicted in theory and synthesized by various experimental methods. Our ultimate goals is to identify a few specially advanced novel 2D materials and their device structures.