N_CityU134/13
Investigation of Antenna Design and Electromagnetic Compatibility in Radio-Frequency System-in-Package

Hong Kong Principal Investigator: Prof Kwok Wa Leung (City University of Hong Kong)
Mainland Principal Investigator: Prof Jun Fa Mao (Shanghai Jiao Tong University)

With the rapid development of wireless communications, it has been a trend to integrate the antenna with RF module, which is known as antenna-in-package (AiP). Using this approach, wireless systems can be made smaller in size, lower in cost, and more efficient in power consumption. However, the current AiP technology is not mature and improvements in the antenna gain, radiation pattern, and electromagnetic interference are needed. The idea of RF system-in-package (RF-SiP) is becoming popular and some research works on the antenna-integrated RF-SiP (AIRF-SiP) have been done. In this project, new antennas for AiP and AIRF-SiP designs along with their electromagnetic compatibility (EMC) will be studied.

Normally, the antenna and circuit of AiP/AIRF-SiP designs are arranged horizontally or vertically. In this project, a third arrangement of placing the circuit inside the hollow dielectric resonator antenna (DRA) will also be made. Different new hollow DRAs will be investigated and applied to AiP and AIRF-SiP design, including the linearly polarized DRA, circularly polarized DRA, omnidirectional DRA, differential DRA, and dualband DRA. Their EMC problems will be examined and tackled.

The antenna gain of hollow DRA is typically ~ 5-7dBi. In this project, the perforated DRA array will be studied to obtain higher antenna gains. It can be easily fabricated by simply making a lattice of holes on a dielectric substrate. In addition, the millimetre-wave Fabry-Perot resonator antenna (FPRA) will also be used. It has a very simple structure with its gains higher than 10dBi. For the first time, the FPRA will be realized using the LTCC technology. This project will apply the perforated DRA array and FPRA to AiP designs and study their EMC.

In the study of EMC, a new Generalized Transition Matrix (GTM) method will be developed to take into account the hybrid effects of electromagnetic, thermal, and stress fields. To facilitate the study, an RF-SiP platform will be built for co-designing the antenna and RF circuit. Also, the electrical and EMC characteristics of the AiP and RF circuit will be determined by developing system-level measurement and testing techniques.

The project will be divided into two parts. Part 1 focuses on the AiP/AIRF-SiP designs, which will be carried out at City University of Hong Kong. For Part 2, different EMC problems of the AiP/AIRF-SiP designs will be examined and solved at Shanghai Jiao Tong University. Finally, the co-design and measurement of the antenna and circuit will be jointly conducted.

N_HKUST605/13
Delay-Aware Radio Resource Management: Theory and Algorithm Design for Cloud Radio Access Networks

Hong Kong Principal Investigator: Prof Vincent Lau (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Mugen Peng (Beijing University of Posts and Telecommunications)

Cloud Radio Access Network (C-RAN) is a promising new architecture for future 5G cellular communications. However, to fully unleash the potential of C-RAN, intelligent and self-organizing radio resource management (RRM) is needed and there are various technical challenges involved to support real-time bursty mobile data traffic. In this project, we focus on establishing a theoretical framework for the design and optimization of scalable and low complexity RRM algorithms for C-RAN architecture. In order to support delay-sensitive applications, the RRM design framework has to embrace information theory as well as queueing theory.

N_HKUST636/13
Investigation of the bulk and interface traps in III-nitride semiconductor heterostructure power electronic devices

Hong Kong Principal Investigator: Prof Jing Chen (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Bo Shen (Peking University)

Global trends toward energy-saving and energy-efficiency have created strong demand for technological advancements in power converters for electric energy processing. At the heart of the power converters, semiconductor power devices are playing a critical role with silicon serving as the base material currently. With the rapid development and progress made during the last three decades, Si power devices are approaching their fundamental limits in performance and are facing great difficulties in meeting the performance demand (in power conversion efficiency, switching speed and harsh environment operation capabilities, etc.) of many power-hungry electronic devices, electrical appliances, electric vehicles and the emerging renewable energy power management systems.

With its superior material properties, wide bandgap GaN-based group III-nitride (III-Nitride) power devices, especially in the form of AlGaN/GaN HEMT (high electron mobility transistor) and MIS-HEMTs (metal-insulator-semiconductor HEMTs), have received great attention and impressive device performance have been demonstrated. The capability of implementing GaN power devices using GaN-on-Si platform is a particular advantage over SiC (another competing wide bandgap semiconductor) because of the highly scalable (up to 8-inch currently) and low-cost Si substrate. However, the commercialization of the GaN-based power devices is still hindered by major issues related to device stability and reliability. Most of these issues are caused by the bulk and interface traps that are still poorly understood. Furthermore, there is a lack of adequate and complete evaluation of their impacts on the device performance and stability/reliability.

In this project, utilizing the vast buildup of technical know-how and solid understanding of fundamental physics about III-nitride materials and devices by both the Hong Kong and Mainland research teams, we propose to conduct a systematic and comprehensive investigation on the origins and underlying physical mechanisms of bulk and interface traps. For the bulk traps, our focus will be on developing techniques to identify trap energy levels and studying the impacts of the bulk traps on device breakdown voltage and current collapse. The interface traps at dielectric/III-nitride are critical to the threshold voltage stability. Because of the diverse behavior of shallow and deep traps, various techniques capable of identifying the interface trap level and density will be developed. The outcomes of this project are expected to provide valuable information to the optimization of buffer design and gate dielectrics that eventually deliver desired device stability and reliability that meet the application standards.

N_HKUST637/13
Effective Location-based Spatial Crowdsourcing

Hong Kong Principal Investigator: Prof Lei Chen (The Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Yunhao Liu (Tsinghua University)

Due to the rapid growth of mobile device uses and amazing functionality provided by mobile devices, spatial crowdsourcing will become more popular than general crowdsourcing, such as Amazon Turk(http://www.mturk.com) and Crowdflower (http://crowdflower.com/). However, to implement a spatial crowdsourcing platform, effective and efficient solutions for motivating workers, assigning tasks, aggregating results and controlling data quality must be developed. Therefore, in this project, we will investigate the following key techniques: 1) effective intensive mechanisms to encourage mobile device users to participate in crowdsourcing tasks; 2) automatic user profile mining methods; 3) optimal task assignment solutions; 4) novel data integration models; 5) intelligent data quality control mechanisms. Based on developed key techniques, we will implement a prototype system for general spatial crowdsourcing tasks. The outcome of this project will have significant impact on spatial crowdsourcing. The proposed solutions will not only lay a solid theory foundation for spatial crowdsourcing, but also help building an effective spatial crowdsourcing platform to well utilize wisdom of Crowds in our daily life.

N_HKU714/13
Key technology in time-reversal based optical scanning holography and its application on fluorescent biological specimens

Hong Kong Principal Investigator: Dr. Edmund Yin-mun Lam (The University of Hong Kong)
Mainland Principal Investigator: Prof Bingzhong Wang (University of Electronic
Science and Technology of China)

Optical Scanning Holography (OSH) is an optical imaging technique that records two-dimensional (2D) holographic information of a three-dimensional (3D) object by lateral raster scanning. Unlike other 3D imaging methods such as confocal microscopy, this technique does not require axial scanning, and unlike other digital holographic techniques, OSH can capture incoherent emissions such as fluorescence. These unique features indicate that OSH has great potential in imaging 3D biological specimens, particularly in their dynamic cellular processes, where these specimens are often stained with fluorescent dyes and sub-micron resolution imaging is highly desirable. This resolution requirement is currently the limiting factor of the OSH technology, which is what we are addressing in this proposal. Our objective is to develop the time-reversal (TR) technique for OSH, which can focus light both in space and time, for the super-resolution of the OSH system. We focus on three main areas: (1) The incorporation of the TR technique relies on modifying the optical transfer function (OTF), so the first area of investigation is to design the appropriate OTF through modification of the optics hardware. Alongside, we will need to develop the associated theory on manipulation of light in the OSH scattering medium and verify it via both numerical simulations and experiments. (2) Based on the highly scattered OTF, we will further develop the mathematical algorithms with TR technique, especially in image reconstruction. This includes formulating the appropriate optimization problems and solving with efficient iterative techniques. (3) We will conduct extensive experiments in the application of TR-based OSH on 3D fluorescent biological specimens. We will characterize both the resolution and the acquisition time, and investigate the results with colleagues in the life science area on the adoption of OSH in their work. We envision that our work in this proposal will establish the TR-based OSH as a unique technology in microscopy, and in turn contribute to the advancement of life science.

N_HKU729/13
Research problems on carving and tamper detection of fragmented multimedia evidence for forensic investigation

Hong Kong Principal Investigator: Dr. Siu-ming Yiu (The University of Hong Kong)
Mainland Principal Investigator: Dr. Xiamu Niu (Harbin Institute of Technology)

There is an increasing number of crime cases involving computers and new generation storage devices. Quite a number of them also involve multimedia files (photos and videos) such as faked photos, faked videos and child pornography. Digital evidence becomes a major source of evidence. In China, the Civil Procedure Law was amended in 2012 to admit electronic data as a formal category of evidence. In Hong Kong, there were already many cases that were supported by digital evidence. On the other hand, criminals are getting smarter. They try to destroy the original evidence. It is common that a forensic investigator needs to collect the fragments of the deleted files from the storage devices and reconstruct the photo or the video for evidence (referred as "data carving"). The performance of existing carving tools is not satisfactory if the fragments are mixed from more than one photo and most of the fragments are not stored consecutively in the devices (which is common in new generation storage media such as solid state drive (SSD)). Also, there exist anti-forensic algorithms that help users to tamper photos (creating faked photos). Advanced tamper detection techniques are needed to identify these faked photos/videos. Existing techniques usually only work on complete images. However, the carved file in crime cases may be incomplete. A more scientific measure should also be designed to provide a confidence index on how accuracy the tamper detection result is on the carved multimedia file to assist the judge to assess the validity of the evidence.

In this proposal, we try to provide solutions to the above problems: (1) develop more robust data carving algorithms to handle mixed fragments from multiple files; (2) develop advanced tamper detection algorithms on (incomplete) carved files; (3) develop a scientifically sound confidence measure on how likely the carved file is correct and being tampered. The results have high impact on helping law enforcement units to effectively identify multimedia digital evidence. The developed methods could be used as a reference for an acceptable methodology for retrieving deleted digital evidence in Hong Kong Courts. The confidence measure could be used as a preliminary reference on how to evaluate the validity of carved digital files.

N_CUHK454/13
Structural Studies of Flagellar Motor Switch from H. pylori: A Combination of X-ray Crystallography and Cryo-electron Microscopy Approaches

Hong Kong Principal Investigator: Dr. Wing-ngor Shannon Au (The Chinese University of Hong Kong)
Mainland Principal Investigator: Dr. Qin-fen Zhang (Sun Yat-sen University)

Motile bacteria swim and respond to environmental stimuli by controlling the rotation of the flagellum. Unlike other biological motors, the flagellar motor is bidirectional and thus can rotate in clockwise or counterclockwise directions. Construction of this switchable rotary motor requires self-assembly of about 25 proteins into ring structures that permits transmission of proton motive force from the stator to mechanical work of rotor and the filament. Among all the components in the flagellar system, motor switch complex comprising of FliG, FliM and FliN plays a critical role in torque generation, rotation switching and flagellar export. How different switch proteins are assembled into a macromolecular complex and co-operated to drive rotation in both direction is unclear. Interestingly and unusually, gastric pathogen Helicobacter pylori harbors an additional switch protein FliY and a wider motor switch structure that may associate with its ability to colonize and move in the acidic and viscous gastric mucus layer.

Our recent structural studies have revealed the crystal structures of motor switch proteins FliG, FliM and FliG-FliM complex from H. pylori. Together with biochemical and genetics studies, molecular interaction between FliY and FliN has also been demonstrated. Furthermore, comparison of the thermodynamic parameters of FliG-FliM interactions between H. pylori and E. coli suggests that the molecular basis underlying the motor switch assembly is differ across bacterial species. In this study, we will apply a combination of protein x-ray crystallography and cryo-electron microscopy to obtain the structure of motor switch complex of H. pylori. This is a joint project gathering the strength of crystallography in solving molecular structures at atomic resolution and of cryo-electron microscopy in studying supramolecular complexes. Specifically, we will determine the crystal structures of motor switch complexes by x-ray crystallography. In parallel, the whole architecture of the motor switch will be studied by single particle cryo-electron microscopy. We will also characterize the three-dimensional in vivo structure of the motor switch by cryo-electron tomography and define the location of each switch protein by immunoelectron microscopy. Our work will generate novel mechanistic insights toward understanding flagellar motor assembly and rotational switching. In the long term, the structural model will enhance our knowledge of other macromolecular assemblies and provide a framework for rational design of nanomotors.

N_HKU703/13
Identifying critical transitions and gene regulatory networks controlling phases of chondrocyte differentiation in the growth plate

Hong Kong Principal Investigator: Prof Kathryn Song-eng Cheah (The University of Hong Kong)
Mainland Principal Investigator: Prof Michael Q. Zhang (Tsinghua University)

The endochondral bones of the skeleton develop from mesenchymal progenitors in a process termed endochondral ossification. These progenitors differentiate into round chondrocytes which flatten, proliferate and arrange in columns. As they mature, chondrocytes exit the cell cycle and become prehypertrophic and undergo hypertrophy to form a structure termed the growth plate, comprising layers of differentiating chondrocytes. The growth plate mediates linear bone growth. Hypertrophy, is marked by the characteristic enlargement of the post-mitotic prehypertrophic chondrocytes (PHC). How are these transitions from a small PHC cell to an enlarged hypertrophic state controlled? Studies of human and mouse mutants show that the sequential steps of chondrocyte differentiation are tightly controlled by many signaling pathways. However the specific regulatory mechanisms and factors that mediate the transitions from a proliferative to prehypertrophic and hypertrophic states are not fully understood.

We will test two hypothetical models of how the transitions from a proliferative to prehypertrophic and hypertrophic states are controlled. One model proposes transient changes in expression of a small population of genes ("critical transition genes") initiate the key changes required to progress from one differentiation state to the next. The second model proposes that a "transition zone" is established in which chondrocytes simultaneously up-regulate and down-regulate distinct sets of genes, thereby triggering progression to the next differentiation state.

We will use a multidisciplinary approach, to test these models. The Sox9 transcription factor is essential for the specification and differentiation of chondrocytes. It is expressed in all chondrocytes except hypertrophic chondrocytes. The Col10a1 gene is expressed only in prehypertrophic and hypertrophic chondrocytes in the growth plate and is negatively regulated by Sox9. We will exploit these characteristic expression patterns to develop methodology to isolate and fractionate chondrocyte populations at different stages of differentiation from the mouse growth plate. For each fractionated chondrocyte population, we will generate global gene expression information (transcriptome). The epigenetic status of cells is closely associated with differentiation states. Tri-methylation of specific lysine residues in histone H3 in upstream regions can label genes that are poised for activation upon receipt of differentiation signals. By contrast methylation of different specific lysine residues can distinguish between enhancer regulatory elements and regions of repression. Therefore identifying and characterising the epigenetic marks associated with the Col10a1 gene locus in proliferating, prehypertrophic and hypertrophic chondrocyte states will provide insights into the regulatory controls mediating the different transition states. We will combine detailed analyses of the ordered changes and fluctuations in the transcriptomes of the different chondrocyte populations, mathematical modelling, analyses of epigenetic changes and regulatory network transitions, followed by targeted functional validations.

N_HKU709/13
Study Role of PCNA-binding protein TRAIP in Replicative Stress Responses and Tumor Suppression

Hong Kong Principal Investigator: Dr. Michael Shing-yan Huen (The University of Hong Kong)
Mainland Principal Investigator: Dr. Jianye Zang (University of Science and Technology in China)

Before a cell divides, it must duplicate its entire genome such that its daughter cells receive an exact replica of its genetic material. With 3 billion base-pairs of DNA in a human cell, this daunting task of error-free genome duplication is accomplished by the concerted effort of the core DNA replication machinery and an emerging list of DNA damage-repair (DDR) factors. Their coordinated interactions allow continuous surveillance and restoration of DNA damage and misincorporated nucleotides prior to chromosome segregation. Not surprisingly, DNA replication-associated defects contribute to a host of devastating human syndromes, including premature aging, cancer and neurodevelopment disorders.

Towards understanding how cells promote genome stability we have isolated TRAIP as a new DDR component that associates with the replication factor PCNA. Our preliminary findings indicate that TRAIP localises to DNA lesions and is required for cell resistance to replicative stress. We propose that TRAIP, via its interaction with PCNA, enforces replicative stress responses to promote genome stability and cell proliferation.

TRAIP deficiency has profound consequences in organismal development and survival. By elucidating the molecular basis of TRAIP-dependent responses to replicative stress, our study will reveal how TRAIP contributes to the faithful transmission of the genome, will advance the current understanding of the highly intertwined network of the mammalian DNA damage response, and will aid in the knowledge-driven development and rationalisation of therapeutics for genome instability-associated human diseases.

N_CUHK439/13
Role of TRPC5 Channels in Multidrug Resistance in Adriamycin-resistant Breast Cancer Cells

Hong Kong Principal Investigator: Prof Xiao-qiang Yao (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Jian Jin (Jiang-Nan University)

Development of multidrug resistance in tumor cells is a serious problem in cancer chemotherapy. During chemotherapy, numerous tumor cells overproduce a 170 kDa protein named P-glycoprotein (P-gp), which functions to pump different classes of cytotoxic drugs from tumor cells, rendering the tumor cells resistant to multiple chemotherapeutic drugs. Moreover, the drug resistant phenotype can transfer from drug-resistant tumor cells to drug-sensitive tumor cells via microvesicles. Microvesicles are small membrane vesicles (0.1-1 £gm in diameter) derived from membrane budding. They can mediate intercellular cross-talk by transferring their intra-vesicular contents (P-gp, proteins, transcriptional factors, micro-RNAs, etc.) from donor to recipient cells. Our previous study found that P-gp overproduction was regulated by a Ca2+-permeable ion channel TRPC5 (canonical transient receptor potential isoform 5) through a transcription factor NFATc3. Inhibiting/suppressing TRPC5 activity/expression could reduce the P-gp expression, reverse the cancer cell drug resistance and inhibit the tumor xenograft growth in athymic mice, indicating a key role of TRPC5 in multidrug resistance. Recently, we also found that TRPC5 was accumulated in microvesicles and that incubation of microvesicles with the drug-sensitive recipient cells transferred the drug resistance property to the recipient cells. These results raise a possibility of microvesicle-mediated transfer of TRPC5 as the possible underlying mechanism for microvesicle-mediated transfer of drug-resistance properties. In addition, we found that TRPC5 is accumulated in the vascular endothelial cells within the drug-resistant tumors and that the channels play a key role in the release of vascular endothelial cell growth factor (VEGF) from the drug-resistant cancer cells, suggesting an important role of TRPC5 in angiogenesis in the drug-resistant tumors. In the present proposal, we plan to examine whether microvesicle-mediated transfer of TRPC5 and/or NFATc3 is indeed important for the acquirement of long-lasting multidrug resistance in recipient cells. We will also explore the role of TRPC5 in angiogenesis. The results from this study should substantially advance our understanding of the molecular basis for the emergence of multidrug resistance in cancer chemotherapy. In the long-term, this study may provide novel treatment strategies for multidrug resistance by targeting TRPC5 and microvesicle-mediated trafficking.

N_HKUST621/13
Development of triterpenoid natural product derivatives as new antiviral drugs directly blocking the receptor binding site of influenza virus

Hong Kong Principal Investigator: Prof Zhihong Guo (The Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Demin Zhou (Peking University)

Seasonal and pandemic influenza infections pose a constant threat to public health. A valid therapeutic intervention to reduce mortality is to disrupt the virus life cycle in the acute phase of the influenza infections with small molecule chemical agents. Currently, there are only a few approved drugs available for this purpose, such as oseltamivir (Tamiflu ). The effectiveness of these drugs, however, has been greatly reduced due to widespread drug resistance and new antiviral agents are urgently needed. Recently, we have found that a galactose conjugate of orleanolic acid, a triterpene natural product, exhibits anti-influenza activities likely through blocking the receptor recognition site of the viral surface protein hemagglutinin. Here, we propose to develop this conjugate into a new antiviral drug. We will determine the high-resolution crystal structure of hemagglutinin in complex with the triterpene conjugate and establish the mode of the anti-influenza mechanism for the small molecule antiviral agent at the atomic level. In the meantime, we will determine the binding specificities of the small molecule towards different hemagglutinin subtypes and correlate these binding data to its cell-based activity assay results. These investigations will reveal the structure-activity relationships for the triterpene conjugate to aid in its optimization as an anti-influenza agent. In addition, we will optimize the potency and other drug properties of the triterpene conjugate through multiple rounds of analog synthesis and activity evaluation, guided by cell-based antiviral assays and the structure-activity relationships acquired from the biochemical and structural studies. These two parts of the work will be performed separately by two research teams with intimate interactions. Through this collaborative study, one or more anti-influenza drug candidates with a new molecular target will be obtained for the clinical phases of drug tests, which may eventually lead to a new class of anti-influenza drugs without pre-existing resistance and save lives.

N_PolyU505/13
High-performance sunlight-driven water purification pilot plant based on plasmonic photocatalysis and microfluidic planar reactors

Hong Kong Principal Investigator: Dr. Xuming Zhang (The Hong Kong Polytechnic University)
Mainland Principal Investigator: Dr. Weixing Yu (Chinese Academy of Sciences)

Clean water supply is crucial to the urbanization of China but the natural water resource is limited and recently severely polluted. Photocatalytic purification of treated wastewater can immediately boost up the total amount of water supply. However, large-scale applications are still rare as limited by low efficiency, unsatisfying sunlight-responsive photocatalysts and lack of high-performance pilot plants. This project aims to tackle these problems by incorporating microfluidics technology and plasmonic effect into pilot plants.

This research will focus on four tasks: (1) to develop the next-generation photocatalytic reactors to solve the problems of low efficiency and complicated operation; (2) to develop new plasmonic photocatalytic nanomaterials and new large-area fabrication techniques for significant enhancement of photocatalytic efficiency; (3) to utilize photon-capturing and self-cleaning surface nanostructures on the photocatalytic reactors so as to enhance the photon utilization efficiency and the climate tolerance; and (4) to build up a pilot plant for high-performance sunlight water purification with high throughput (> 1,000 l/h).

The two teams are experienced in microfluidics, photocatalysis and nanomaterials. Through a close collaboration, this project is expected to provide a paradigm of high-performance, energy-saving, sunlight-driven water purification and may lead the photocatalysis to practical large-scale applications.

N_HKUST627/13
Response of air-sea CO2 fluxes in the northern South China Sea to the carbon and nutrient export associated with the Pearl River plume (PRP)

Hong Kong Principal Investigator: Prof Jianping Gan (The Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Minhan Dai (Xiamen University)

Pearl River plume, the river water spread over the continental shelf in the northern South China Sea (NSCS) by oceanic currents, is loaded with rich nutrients and carbon. It produces biological blooms, alters the biogeochemical properties and thus modulates CO2 concentration and associated air-sea CO2 fluxes in the NSCS waters. These processes are governed by the coupled physical-biogeochemical processes. This project, based on unique combination of expertise on physical oceanography at the Hong Kong University of Science and Technology, and on biogeochemistry at Xiamen University, is to examine quantitatively the exports of carbon and nutrients associated with the Pearl River plume as well as their effect on CO2 fluxes over the shelf, through both field observation and numerical modeling.

N_CUHK448/13
Three Dimensional Graphene/Metal Oxide (Sulfide) Composite Nanoarchitectures for Anode Applications in Li-ion Batteries

Hong Kong Principal Investigator: Prof Quan Li (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Yang-long Hou (Peking University)

The high specific capacity associated with many metal oxides (sulfides) makes them a most promising category of anode candidate for Li-ion batteries. Nevertheless, this family of materials suffers from low cyclability as a result of the materials' low electrical conductivity and/or volume change during cycling. Introducing a highly conductive component such as graphene to form composite with the metal oxide (sulfide) provides a most feasible solution, that is, the electrical conductivity of the active material can be largely increased, so that the overall electrochemical performance of the anode is significantly improved. In fact, graphene serves as an extremely promising electrode hosting material in Li-ion batteries, not only due to its high electrical conductivity, but also because of its large surface to volume ratio, and excellent chemical/mechanical stability.

Here we propose a most promising configuration for the graphene/metal oxide (sulfide) composite as anode for Li-ion batteries. Instead of employing the conventional two dimensional layered graphene/ metal oxide (sulfide), we will construct three dimensional (3D) interconnecting graphene networks as the hosting electrode for metal oxide (sulfide). Such nanostructured architecture brings in unique features including (1) an integrated conducive hosting network and excellent contact between the active material and electrode (electrolyte); (2) short ionic/electronic pathways for efficient carrier transport; and (3) extra space to accommodate the volume expansion of metal oxide (sulfide) during discharging/charging cycles.

We will work on the most critical problems associated with the 3D graphene/metal oxide (sulfide) composite materials, that is, the effective incorporation of metal oxide (sulfide) into the interconnecting network of 3D graphene, and the identification of the optimized interfacing mechanisms that brings the best anode performance. In addition, we will develop feasible strategies that "glue" the 3D graphene network directly onto the current collector, providing a simplest and most straightforward device configuration without the aid of additional binders and additives. Both the material and system parameters will be varied in a systematic manner by controlling the processing conditions, and the optimum configuration of the proposed 3D graphene/metal oxide (sulfide) composite nanoarchitecture will be identified. By combining research expertise in controlled nanostructure synthesis, graphene based composite material fabrication, and local compositional/structural and electrochemical characterizations of Li-ion battery materials from the HongKong and the mainland teams, the present proposal will lead to high capacity and long cycle life anode for the new generation of Li-ion batteries.

N_CUHK449/13
Design and Biological Response of Biodegradable Mg-Sr-Zn Alloy for Ligament/tendon-bone Reconstruction

Hong Kong Principal Investigator: Prof Ling Qin (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Yu-feng Zheng (Peking University)

Tendon or ligament injury at its bony insertion (TBI) is a common orthopaedic problem and remains a big challenge as its repair takes place between two different tissues with limited regeneration capability of insertional fibrocartilage zone at the tendon-bone healing interface. The typical injuries at TBI include avulsion of the tendon, reconstruction of the ligament, partial patellectomy, and tendon transfer for reconstruct tendon/ligament-bone interface. In order to achieve optimal treatment for BTI repair, we shall involve good surgical fixation with biomaterials and/or implants, and postoperative biological and biophysical enhancement. Magnesium (Mg) is one of the major mineral compositions of bone matrix and 60% of the body Mg is stored in bone. Mg can now be fabricated into a biodegradable metal for potential injury fixation that also avoids the second operation conventionally needed for removal of the implanted fixator. The degradation of Mg makes it possible to become an alternative absorbable implant material for bone screws and plates in orthopaedics that would be superior to currently available biodegradable implants made of polymer. As pure Mg degrades or corrodes too fact that does not meet our orthopaedic application, especially for application for BTI repair fixation, alloying elements plus an amorphous single-phase structure may significantly improve corrosion characteristics of Mg. Strontium (Sr) and zinc (Zn) are proven to be able to improve the corrosion resistance and the mechanical strength after integration into pure Mg. We therefore developed a novel biodegradable or biocorrosive Mg-based alloy with osteoinductive Sr and corrosion-resistant Zn. Our pilot in vitro and in vivo study shows favourable bone and soft tissue stimulating effects as compared with our previous Mg or Mg alloys with either Mg-Sr or Mg-Sr-Ca. This encouraging finding forms a solid foundation to propose the current collaborative study to develop a clinically desirable Mg-Sr-Zn interference screw for reconstruction of common sports injury involving BTI repair, such as anterior cruciate ligament (ACL) reconstruction. We will use rabbits as an experimental model for ACL reconstruction to test the potential of our innovative interference screw made of biodegradable Mg-Sr-Zn alloy for ACL reconstruction. Both standard and advanced systemic evaluations will be employed for studying the efficiency of BTI healing with regards to the degraded Mg-Sr-Zn irons, including radiography, micro-CT, scanning electronic microscope, mechanical test, histology and histomorphometry. The significance of our collaborative project will develop an innovative orthopaedic implant will facilitate good fixation and better healing for BTI repair, including earlier recovery, reduction of complications, the costs associated with potential delayed healing, and avoiding second operation associated with implant removal. This project will have profound impact on innovation of orthopaedic implants for medical applications.

N_CUHK450/13
Processing and Characterization of 3D Graphene Based Thermal Interface Materials

Hong Kong Principal Investigator: Prof Ching-ping Wong (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Shu-lin Bai (Peking University)

This proposal aims to develop a thermal interface material (TIM) with both high mechanical compliance and high thermal conductivity using a three-dimensional (3D) graphene network filled with graphene nanosheets/polymer blend. TIM is a key component in a thermal management system and is critical for the operation of electronic devices with high power and thus high heat flux across interfaces.

In this proposal, we will fabricate high-quality 3D graphene foams with controllable nanostructures using a chemical vapor deposition method. A scalable process will be developed to produce 3D graphene/polymer composites in two steps: (1) blending of graphene nanosheets with liquid phase polymer, and (2) filling of the blend into the 3D graphene foam. To examine the potential of the composite as a TIM, we will characterize microstructures, thermal and mechanical properties of the composite, such as pore size and layer number of 3D graphene, dispersion of graphene nanosheets, interface bonding between graphene and polymer, thermal conductivity and tension, compression and creep coefficients. Microscopic component assembly models will be developed to describe the deformation and failure behavior of the composite and to predict its equivalent elastic modulus and thermal conductivity. The results will lead to fundamental understanding on the relationship between processing, microstructures, thermal and mechanical properties of 3D graphene based TIMs.

Based on theoretical and experimental results, an optimized processing routine, a comprehensive characterization platform and detailed microscopic models will be established for 3D graphene/polymer composites, which will provide a solid theoretical and experimental foundation for engineering applications of graphene as thermal interface materials.

N_CUHK451/13
Palladium-catalyzed Asymmetric Allylic Alkylations and Its Application in Total Synthesis of Cryptotrione and Bolivianine

Hong Kong Principal Investigator: Prof Henry N C Wong (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Xue-long Hou (Shanghai Institute of Organic Chemistry)

The development of effective C-C bond formation reaction stereoselectively for organic chemistry, especially for drug discovery and materials science, is of fundamental importance both in basic research and in industrial applications. Therefore, the aim of this project is to develop an efficient protocol of Pd-catalyzed asymmetric C-C formation reaction using ferrocene-based P,N- and SIOCPhox ligand series on the basis of our previous works, which can be applied to the total synthesis of bolivianine and anticancer terpenoid cryptotrione with an IC₅₀ value of 6.44 ±2.23 μM (only slightly weaker than the clinically used anticancer drug etoposide (VP-16, IC₅₀ 2.0 μM)), and to the efficient synthesis of drug or lead compounds in the related pharmaceutical industry.

In our previous studies, Xue-Long Hou successfully developed a series of ferrocene-based P,N-ligands, SIOCPhox and demonstrated their power in the control of the regio- and enantio-selectivities of palladium-catalyzed asymmetric allylic alkylation with several "hard" carbanions. These endeavors encouraged us to further develop novel Pd-catalyzed asymmetric C-C formation reaction using ferrocene-based P,N- and SIOCPhox ligand series and apply them in organic synthesis and drug discovery.

In the first phase of our project, we propose to improve and develop novel Pd-catalyzed asymmetric cyclopropanation and allylic alkylations using ferrocene-based P,N-ligans and SIOCPhox ligand series with tunable electronic and steric properties, investigating in details the catalytic properties and the reaction mechanisms.

The second phase of this project will be concerned with the newly developed protocol's application in the synthesis of more elaborate structures leading to the total synthesis of structurally complex and biologically significant natural products such as anticancer terpenoid cryptotrione and bolivianine.

The third phase of our project will involve the application of novel Pd-catalyzed asymmetric cyclopropanation and allylic alkylations using ferrocene-based P,N-ligands and SIOCPhox ligand series in the synthesis of potential active compounds that could provide the important insights into their structure activity relationships (SARs).

The final phase of this project will be placed on the potential application in the efficient synthesis of drug or lead compounds that can be derived from natural products cryptotrione and bolivianine in the related pharmaceutical industry.

Generally, this relevant research in our project will demonstrate the power and potential of novel Pd-catalyzed asymmetric cyclopropanation and allylic alkylations using ferrocene-based P,N-ligans and SIOCPhox ligand series to render scarce biologically active natural products for chemical and biological investigations. Moreover, structural analysis of the relevant compounds produced in this proposal will be carried out and this will lead to a greater understanding of the fundamental chemistry of the novel reactions involved. This project would also yield invaluable information about a range of novel synthetic reactions.

N_CUHK453/13
Novel One-dimensional Quantum States of Spin-orbit Coupled Ultra Cold Atoms beyond Standard Paradigms

Hong Kong Principal Investigator: Prof Qi Zhou (The Chinese University of Hong Kong)
Mainland Principal Investigator: Prof Jing Zhang (Shanxi University)

The study on many-body states in one dimension, where quantum effect is most profound among all dimensions, is one of the major themes in condensed matter physics in the past several decades. Luttinger liquid theory has been well known as a standard and universal theoretical paradigm to describe one-dimensional quantum states. The recent realization of synthetic spin-orbit coupling for neutral atoms provides physicists an exciting new means to control quantum many-body systems. When one-dimensional ultra cold atoms meet synthetic spin-orbit coupling, unprecedented new quantum many-body states will emerge.

With a cooperative effort of theoretical and experimental studies, we will produce spin-orbit coupled ultra cold atoms confined in one-dimensional traps, use spin-orbit coupling as a unique tool to tame both the kinetic energy and interactions, and create quantum many-body states not achievable in an ordinary one-dimensional system. When the single-particle spectrum at low energies is tuned to be distinct from the ordinary quadratic one or even to be completely flattened, the Luttinger liquid theory is no longer applicable. Meanwhile, spin-orbit coupling controlled partial-wave mixing in two-particle scattering gives rises to effective interactions in many-body systems that are not captured by the standard pseudopotential method. These new approaches of controlling the many-body system lead to the rise of novel quantum states beyond standard paradigms in this project.

Our experimental techniques include a sequence of state-of-the-art ones, including Feshbach Resonance, Time-Of-Flight image, Radio-Frequency Spectroscopy and Momentum-Resolved Raman Spectroscopy, all of which have been readily implemented by the experimental team. High-resolution in-situ images, a platform we are building up now, will also be used. Our theoretical techniques include exact solutions for few-body problems, and analytic and numerical methods for many-body systems, such as effective theory, Bethe ansatz, time-evolving block decimation algorithm and density matrix renormalization group. All these experimental and theoretical techniques are suitable for studying strongly correlated systems in one dimension.

Our project will lead to discoveries of novel quantum states with no counterpart in other systems, using the existing experimental techniques. This project will establish a platform to access new physics unexplored in the literature, including spin-orbit coupling controlled effective interactions in one dimension, and highly tunable effective spin-orbit coupling in optical lattices. It also enables new theories to characterize the effect of spin-orbit coupling in one-dimensional interacting many-body systems.

N_PolyU506/13
The application of organic electrochemical transistors as a state-of-the-art platform for label-free, ultrasensitive, high throughput and portable nucleic acid detection

Hong Kong Principal Investigator: Dr. Feng Yan (The Hong Kong Polytechnic University)
Mainland Principal Investigator: Prof Huangxian Ju (Nanjing University)

Nucleic acid analysis has significant applications in gene expression monitoring, viral and bacterial identification, biowarfare and bioterrorism agents detecting, and clinical medicine. In particular, rapid, cheap and accurate detection of nucleic acid molecules in a portable platform is critical to the point-of-care diagnostics. However, it is challenging to detect the nucleic acid molecules especially short DNA and RNA strands. Organic electrochemical transistors (OECTs) have many advantages in the applications of biosensors. OECTs can be fabricated by solution process at low temperature and are thus potentially low cost. The organic devices show good flexibility and biocompatibility and can be integrated with biological systems for in vitro or even in vivo detections. More importantly, OECTs can be miniaturized without the degradation of their performance. So the devices can be used in high density multifunctional sensor arrays.
In this project, we will make use of the advantages of OECTs to design novel DNA and RNA sensors by combining the expertise of the two research groups. We will focus on the following three objectives: (1) To realize OECT-based nucleic acid sensors with the detection limit down to attomolar level; (2) To realize ultrasensitive microRNA analysis; (3) To fabricate OECT arrays for high throughput label-free nucleic acid sensing. The success of the proposed studies will enable novel technologies for portable and label-free DNA (microRNA) analysis with ultrahigh sensitivity and selectivity. The OECT arrays integrated in microfluidic channels will be ideal candidates for multiplexing and high throughput DNA (microRNA) sensors. Since the organic devices are mechanically flexible, biocompatible, potentially low cost and suitable for disposable applications, the OECT-based nucleic acid sensors will find promising applications not only in hospitals or laboratories for clinical diagnosis and gene expression monitoring but also in some healthcare products which will have a huge market in the future.

N_HKUST623/13
Development of polymer/polymer-blend-based bulk-heterojunction organic photovoltaics

Hong Kong Principal Investigator: Dr. He Yan (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Dr. Fei Huang (South China University of Technology)

A common organic photovoltaic (OPV) cell contains the blend of a p-type polymer and an n-type fullerene. Polymer/fullerene-based OPVs can achieve high efficiencies. However, they have limitations due to the poor light absorption properties and the high cost of fullerenes. It is desirable to replace the fullerene with a low-cost and high-absorption n-type semiconducting polymer to construct polymer/polymer-based OPVs (PP-OPVs).

During the past decade, the development of PP-OPVs has been extremely slow due to the unavailability of high-performance n-type semiconducting polymers, which had been a highly challenging research topic historically. In 2009, we reported the first high-mobility n-type semiconducting polymer named as P(NDI2OD-T2), which opened great opportunities for the development of high-efficiency PP-OPVs.

Our approach to PP-OPVs is distinctively different from previous approaches. Since we published our P(NDI2OD-T2) polymer, many reports of P(NDI2OD-T2)-based PP-OPVs have emerged, but none could achieve efficiencies over 1.5%. The main problem for the P(NDI2OD-T2)-based PP-OPVs is that P(NDI2OD-T2) is too crystalline and it forms aggregates that are too large in size (>1um). While large aggregates are ideal for organic transistor applications, they would seriously hurt PP-OPVs, because the optimal size of the crystalline domains in PP-OPVs should be ~20nm. In our original design, the strong aggregation property of P(NDI2OD-T2) comes from its highly regioregular structure and strong pi-pi stacking tendency. To develop new n-type polymers for PP-OPVs, our strategy is to intentionally introduce irregular polymer structures and slight twisting into the polymer backbone. This should effectively reduce the aggregation size of the n-type polymer and allow us to achieve an optimal size of crystalline domains for PP-OPVs.

Following the approach described above, we carried out initial experiments and have already achieved PP-OPVs with dramatically increased efficiency over the best PP-OPVs reported to date. With our promising initial results, we are highly confident of achieving >7% efficiency PP-OPVs within the three years of the proposed project, in which we will launch systematic optimization and understanding work on PP-OPVs. Considering that the PP-OPV field has been limited < 2.7% efficiency for nearly 10 years, the success of our project in achieving 7% efficiency PP-OPVs would be a major advance for PP-OPVs.

We are at a strong position to achieve this goal because the PIs have strong track records in developing world-leading n-type and p-type semiconducting polymers and the PIs have already established successful collaborations and recently achieved a new world-record 9.6% efficiency for single-junction polymer/fullerene OPVs.

N_HKUST626/13
Investigation of new multi-functional materials based on hierarchical porous mixed oxides and carbon aerogels for air purification and disinfection.

Hong Kong Principal Investigator: Prof King Lun Yeung (Hong Kong University of Science and Technology)
Mainland Principal Investigator: Prof Jieshan Qiu (Dalian University of Technology)

Bioaerosols, VOCs and malodor in indoor air can cause illnesses, discomfort and stress on the occupants. The economic impacts go beyond the loss of productivity and medical expenses, but also damage property value and reputation. Airborne infectious agents are responsible for more than 10 million deaths a year and have been the reason for the recent large community outbreak of SARS in Hong Kong, the global H1N1 pandemic and the more recent H7N9 outbreak in East China. It is therefore of great priority to develop an effective means of treating this pollutants. The current approach of combining in series disparate air cleaning and purification technologies is both inefficient and expensive. This project aims to leverage advances in materials and innovation in techniques to design and engineer functional nanomaterials applying principles of nanosafety to create a new multifunctional material that is both safe and effective for air purification and disinfection. This project brings together a multi-disciplinary team of researcher from Hong Kong and mainland China to address an important and urgent regional problem that is also of global relevance.

N_HKBU215/13
Dynamic Regulation of the p53 Pathway and Its Control Over Cell Fate at the Single-cell Level

Hong Kong Principal Investigator: Dr. Jue Shi (Hong Kong Baptist University)
Mainland Principal Investigator: Prof Feng Liu (Nanjing University)

Increasing evidence indicates that the dynamics of key components of signaling pathways play a crucial role in regulating cellular responses to various environmental stimuli; however, there is still a large gap in our understanding of how complex dynamical responses are modulated and how they vary between individual cells. In this proposed collaborative project, by combining highly quantitative single-cell microscopy assays with computational modeling, we will explore the quantitative mechanism by which cell fate is regulated by differential pathway dynamics and how this varies between genetically identical cells. We focus on the process of DNA damage response regulated by the p53 pathway, as an efficient and precisely controlled DNA damage response is crucial for survival and the p53 pathway is known to play a central role in mediating this critical stress response in mammalian cells. Using time-lapse microscopy, we will measure the real-time dynamics of p53 and its main negative regulator, Mdm2, under variable DNA damage, and correlate their dynamics with cell fate outcome at the single-cell level. Based on the experimental data, we will develop a quantitative p53 pathway model and conduct computational analysis to determine how the distinct pathway components and/or feedback structures affect dynamic regulation of the p53 pathway and its control over cell fate, as well as how molecular noise in the p53 pathway renders the broad cell-to-cell variability observed in the isogenic cells. The goal is to acquire quantitative understanding of p53 pathway dynamics and cell fate control at the whole pathway level, unravel molecular mechanism underlying phenotypic heterogeneity in cells with identical genetic background and seek insight towards developing new anticancer strategies. The proposed project brings together highly complementary expertise of the Hong Kong and mainland team in cell biology, live-cell imaging and computational analysis/theory. We envision the collaboration will lead to development of new systemic methodologies that integrate experiments and theories for analyzing single-cell behaviors.