(This article was originally published on EurekAlert! on Mar 17, 2023)
Ice surfaces have a thin layer of water below its melting temperature of 0℃. Such premelting phenomenon is important for skating and snowflake growth. Similarly, liquid often crystallizes into a thin layer of crystal on a flat substrate before reaching its freezing temperature, i.e. prefreezing. The thickness of the surface layer usually increases and diverges as approaching the phase transition (such as melting and freezing) temperature. Besides premelting and prefreezing, whether similar surface phenomenon exists as a precursor of a phase transition has rarely been explored.
Han’s team at HKUST proposes that a polymorphic crystalline layer may form on a crystal surface before the crystal-crystal phase transition and names it pre-solid-solid transition. If carbon atoms near the surface of a diamond could rearrange into a graphite lattice before reaching the diamond-graphite transition temperature, then it would be a so-called pre-solid-solid transition. The mechanism is essentially the same as premelting or prefreezing: the newly formed surface layer lowers the crystal’s surface energy. Han’s team pointed out that it is possible when two polymorphic crystals can form a coherent interface, i.e. the two lattices with appropriate lattice spacing and orientations match perfectly at the interface. Thus, the surface of the denser polymorphic crystal can form a layer of less dense crystal because the newly formed crystal-crystal interface is coherent and costs almost no energy.
Han’s team further confirmed the pre-solid-solid transition in experiment and computer simulation. They found that the surface of a thin-film colloidal crystal with a triangular lattice can form a square lattice as their interface is coherent. The thickness of the surface layer grows with temperature in a power law similar to premelting. These are further confirmed by their simulation about atoms with different interactions.
Premelting has been firstly conjectured by Michael Faraday, the father of electricity, in 1842, but not experimentally confirmed unambiguously until 1980s. The second type of phenomenon, prefreezing, has been proposed and observed in 1950s-70s. The pre-solid-solid transition proposed and observed by Han’s team is the third type of surface wetting precursor of phase transition.
Although it is a phenomenon under thermal equilibrium, they find that surface crystalline layer can also exist in nonequilibrium processes after an abrupt temperature change, such as melting, freezing and polycrystal annealing. The surface layer facilitates the processes, thus may have utility in material fabrication and processing. The trivial solid-solid transition occurring on the free surface after crossing the solid-solid transition point is ruled out from the polycrystal annealing, phase rule or other evidence. In addition, they found the novel double surface layers of liquid and square lattice in the overlapped temperature regime of premelting and pre-solid-solid transition.
Colloids, such as milk, paint, blood, are usually liquid suspensions of small micron-sized particles with Brownian motions. The particles thermal-motion trajectories can be tracked under optical microscopy even inside the 3D bulk of crystals or liquids, which can hardly be obtained in atomic systems. Thus, colloids have been used as a powerful model system to measure the microscopic processes in phase transitions. “Our work shows that colloids are also effective in discovering new type of phenomenon even for the well-known phase behaviors under thermal equilibrium.” Han said, “Its mechanism is simple and thus could be proposed decades ago, but seems to be a blind spot in material science. One future direction is to search for this phenomenon in atomic or molecular crystals. Unlike premelting generally exists in most crystals, pre-solid-solid transition can only exist in polymorphic crystals with low-energy coherent interface. We suggested several candidates of atomic and molecular crystals with coherent interfaces.”
Polymorphic crystals often have different properties, e.g., graphite is soft, black and electric conductive, while diamond is hard, transparent and non-conductive. A crystal with a polymorphic crystalline layer would have tunable surface properties and such layer can regenerate after being worn or corroded off. Thus, it should be a very useful material in applications.
The work is funded by the Hong Kong Research Grants Council and the Guangdong Basic and Applied Research Foundation, and has been published recently in Nature Physics.
A research team from the Hong Kong University of Science and Technology (HKUST) has developed the world’s most productive chemical synthesis which could yield antibiotic anthracimycin and anthracimycin B that is 63 times more than current method. The breakthrough greatly advances the development of anthracimycin-based antibiotics to combat the deadly bacteria infections caused by antibiotic-resistant bacteria and even superbugs.
Since its discovery from an ocean microbe a decade ago, anthracimycin has drawn the world scientists’ attention with its potential to combat against Gram-positive bacteria including the notorious methicillin-resistant Staphylococcus aureus (MRSA) and the bacterium Bacillus anthracis. Among the pathogens, MRSA is known for causing staph infections that are difficult to treat because of the bacteria’s resistance to some commonly used antibiotics such as penicillin. While scientists have been making efforts to develop anthracimycin into a new clinical antibiotic in addressing the mounting threat of antibiotic resistance and treatment failure, the progress is hindered due to anthracimycin’s lack of availability.
Now, a team led by Prof. TONG Rongbiao, Associate Professor of the Department of Chemistry at HKUST and Prof. QIAN Peiyuan, Chair Professor of Department of Ocean Science at HKUST, has designed a productive chemical synthesis strategy which could greatly boost the yield of anthracimycin. Consisting of just ten steps, the world’s shortest synthesis route not only produces 63 times more anthracimycin than current method, but also brings down the cost with a lower use of reagent and solvent during the chemical process.
Meanwhile, the team has also verified for the first time that anthracimycin could inhibit the formation of MRSA biofilms. Compared to vancomycin, which was regarded as the last-line defense against serious infections caused by Gram-positive bacteria, lower concentration of anthracimycin is needed for killing or inhibiting bacterial growth.
Prof. Tong said, “Our novel chemical synthesis overcomes the fundamental bottleneck of limited availability of anthracimycin and enables the scientists to further study its antibiotic activity, laying the groundwork for the clinical drug development. Currently, we are collaborating with a biological laboratory to synthesize a set of anthracimycin antibiotics in the hope of identifying the combination with better antibacterial activity for possible further clinical trials.”
The findings were recently published in Chemical Science.
(This article was originally published on EurekAlert! on February 2, 2023)
Researchers at the Hong Kong University of Science and Technology (HKUST) developed a novel technology which allows genomic DNA and RNA sequencing to be carried out simultaneously in single cells of both frozen and fresh tissues, and identified rare brain tumor cell "spies" disguised as normal cells with this method. This breakthrough facilitates cancer research for some of the most complex and rare tumors, opening new directions for drug target discovery in the future.
Genomic DNA and RNA sequencing are crucial for determining the treatment for cancer, as it offers important information on the tumor’s genomic and molecular composition, or cellular heterogeneity, which influences the disease pathology as well as the tumor’s ability to develop drug resistance. Our present knowledge about cancers do not fully explain why tumors relapse or become resistant to treatment; exploring new dimensions of the tumor composition at high resolution by looking at the DNA and RNA together may provide answers. Existing technologies, however, have limited applicability to simultaneously perform DNA and RNA sequencing in single cells from frozen biobanked tissues, yet these frozen tissues make up most of the readily available clinical cancer samples.
Now, a team led by Prof. Angela WU, Associate Professor of HKUST’s Division of Life Science and Department of Chemical and Biological Engineering and her post-doctoral fellow Dr. Lei YU, developed a new versatile single-cell multi-omic profiling technology scONE-seq, which can analyze frozen cells and difficult-to-obtain cell types like bone and brain. This new method can also simultaneously collect genomic and transcriptomic information in a tumor through a one-pot reaction.
Astrocytoma is a deadly and aggressive type of brain tumor, and patients with this type of tumor have a survival rate of only around 5 percent within five years of diagnosing the disease. Using their new single-cell technology, the team has discovered a small and unique tumor cell subpopulation in a patient’s astrocytoma sample. This unique tumor population disguised themselves as normal astrocytes of the brain, which could escape detection using other common tumor sequencing methods. In addition, this ‘spy’ tumor cell also showed molecular features that are related to drug resistance; the comprehensive role of this ‘spy’ tumor cell in tumor progression will be an important direction for future investigations of this disease and possible drug targets.
Prof. Angela WU said, “By identifying rare tumor cells which might be missed by previous approaches and result in failure to respond to therapy, the scONE-seq approach represents a new path to discovering drug targets and the development of new drugs. We plan to continue our work, using scONE-seq to profile a larger patient cohort, and hope to have more clinically translational outcomes in the future.”
This study was done in collaboration with Prof Jiguang WANG and his team from HKUST’s Division of Life Science and Department of Chemical and Biological Engineering, as well as clinician scientists Dr. Danny CHAN, Dr. Aden CHEN, Dr. Ho Keung NG, and Dr. Wai Sang POON at Chinese University of Hong Kong and Prince of Wales Hospital. The discovery is recently published in Science Advances.
(This article was originally published on EurekAlert! on January 19, 2023)
The study of microRNAs (miRNAs), small RNAs that play important roles in gene regulation in animals and humans alike, have long been a topic of interest to many. How these miRNAs control and regulate gene expression, a subject of great importance in biology and medicine, is often believed to hold the keys to providing effective cures, or strategies, to different phenomenon and symptoms, such as cancer, a result of cell mutations.
While miRNAs and their biogenesis in humans remain the area that attracts the most interest from scientists, the study of Microprofessor, a protein complex that initiates miRNA biogenesis, are often scarce and overlooked in other animals. Recently, a group of scientists at the Hong Kong University of Science and Technology (HKUST) put forward their effort to map out the fundamental mechanisms of C.elegans Microprocessor (cMP), paving the way for future studies into an area that would provide wider perspective on how miRNAs function as a whole across living beings.
Their research was published recently in the open-access journal, Nucleic Acids Research.
“The molecular mechanism of C. elegans Microprocessor (cMP) has remained elusive since its discovery 18 years ago,” said Prof. Tuan Anh NGUYEN, principal investigator of the paper and Assistant Professor, Division of Life Science, HKUST. “Surely, the interest of many has been drawn to the study of miRNA in human beings for good reasons. But the lack of information and fundamental understanding in this complex in C. elegans has driven us to dive in.”
Prof. Nguyen and his team investigated the molecular mechanism of cMP by conducting high-throughput pri-miRNA cleavage assays. In the process, they were able to reveal cMP’s distinctive molecular mechanism, which is very different from what was already known in the human body.
“We demonstrated that cMP consists of two subunits, cDrosha and Pasha, and each has its own ability to measure the stem lengths of C. elegans pri-miRNAs ),” he said. “These two subunits can determine the cleavage sites of the complex using their distinct measuring methods, but more importantly, the mechanism we revealed is different from human MP (hMP) in many aspects. For example, human DROSHA measures only 13 bp and determines the cleavage sites of hMP, whereas DGCR8 (a Pasha orthologue) does not appear to have the ability to either measure or determine the cleavage sites at all.”
With the mechanisms of cMP now apparent, Prof. Nguyen is looking forward to investigating deeper into the structure of cMP/pri-miRNA and making more discoveries.
“We now know that dsRBDs and linkers of Pasha are necessary for the 25-bp upper stem measurement, but as far as fully understanding the structural basis of these substrate numbers? We are just getting started, and we think many in the field will find it worthwhile to pursue further,” said Prof. Nguyen.
In April to May 2019, the coral reefs near the French Polynesian island of Moorea in the central South Pacific Ocean suffered severe and prolonged thermal bleaching. The catastrophe occurred despite the absence of El Niño conditions that year, intriguing ocean scientists around the world.
An international research team led by Prof. Alex WYATT of the Department of Ocean Science at The Hong Kong University of Science and Technology, has investigated this surprising and paradoxical coral bleaching episode. The unexpected event was related to the passage of anti-cyclonic eddies that elevated sea levels and concentrated hot water over the reef, leading to an underwater marine heatwave that was largely hidden from view at the surface. The findings have recently been published in Nature Communications.
Most studies of coral bleaching patterns rely on sea-surface measures of water temperatures, which cannot capture the full picture of threats from ocean heating to marine ecosystems, including tropical coral reefs. These surface measurements conducted over broad areas with satellites are valuable, yet are unable to detect heating below the surface that influences communities living in waters deeper that the shallowest few meters of the ocean.
Prof. Wyatt and colleagues analyzed data collected at Moorea over 15 years from 2005 to 2019, taking advantage of a rare combination of remotely sensed sea-surface temperatures and high-resolution, long-term in-situ temperatures and sea level anomalies. Results showed that the passage of anti-cyclonic eddies in the open ocean past the island raised sea levels and pushed internal waves down into deeper water. Internal waves travel along the interface between the warm surface layer of the ocean and cooler layers below, and, in a previous study also led by Prof. Wyatt, have been shown to provide frequent cooling of coral reef habitats. The present research shows that, as a result of the anti-cyclones, internal wave cooling was shut down in early 2019, as well as during some earlier heatwaves. This led to unexpected heating over the reef, which in turn caused large-scale coral bleaching and subsequent mortality. Unfortunately for local reef biodiversity, the extensive coral death in 2019 has offset the recovery of coral communities that had been occurring around Moorea for the last decade.
A notable observation, in contrast to the 2019 heatwave, was that the reefs in Moorea did not undergo significant bleaching mortality in 2016, despite the prevailing super El Niño that brought warm conditions and decimated many shallow reefs worldwide. The new research demonstrates the importance of collecting temperature data across the range of depths that coral reefs occupy because the capacity to predict coral bleaching can be lost with a focus only on surface conditions. Sea-surface temperature data would predict moderate bleaching in both 2016 and 2019 at Moorea. However, direct observations showed that there was only ecologically insignificant bleaching in 2016, with heating that was short in duration and restricted to shallow depths. The severe and prolonged marine heatwave in 2019 would have been overlooked if researchers only had access to sea-surface temperature data, and the resulting catastrophic coral bleaching may have been incorrectly ascribed to causes other than heating.
“The present study highlights the need to consider environmental dynamics across depths relevant to threatened ecosystems, including those due to the passage of underwater ocean weather events. This kind of analysis depends on long-term, in situ data measured across ocean depths, but such data is generally lacking,” Prof. Wyatt said.
“Our paper provides a valuable mechanistic example for assessing the future of coastal ecosystems in the context of changing ocean dynamics and climates.”
This HKUST-led research was conducted in collaboration with a team of scientists from Scripps Institution of Oceanography at the University of California San Diego, the University of California Santa Barbara, California State University, Northbridge, and Florida State University. The data underlying this study were made possible by coupled long-term physical and ecological observations conducted at the Moorea Coral Reef Long-Term Ecological Research (LTER) site. The long-term analyses conducted here, and the concurrent monitoring of physical conditions and biological dynamics across the full range of depths of island and coastal marine communities, is a model for future research that aims to protect vulnerable living resources in the ocean.
Extensive coral bleaching occurred across depths on the north shore of Moorea during the 2019 marine heatwave.
Photo credit: Peter J. Edmunds.
An animation of the sea-surface temperatures around Moorea compared during the 2016 and 2019 marine heatwaves
An animation of the sea levels (eddy fields) around Moorea compared during the 2016 and 2019 marine heatwaves
Two distinguished scholars at The Hong Kong University of Science and Technology (HKUST) – Professor Jensen Li Tsan-hang and Assistant Professor Dr. Berthold Jäck, both from the Department of Physics, were recently awarded the prestigious 2022 Croucher Senior Research Fellowships, and the Croucher Tak Wah Mak Innovation Awards 2022 by The Croucher Foundation.
Prof. Li’s research revolves around various extraordinary optical phenomena given by metamaterials, with prominent examples such as invisibility cloaking and super-resolution imaging. His current interests are in transformation optics, metasurfaces, non-Hermitian optics and complex media. Metamaterials promise to provide exotic material properties based on tailor-made resonating micro-structures to provide material parameters that do not exist in conventional approaches. With the Croucher Senior Research Fellowship, he will explore new dimensions in constructing and applying metamaterials using non-Hermiticity from material gain and loss, time-varying capability of material parameters, currently known as time-varying metamaterials and applications of metamaterials in the quantum optical regime. These metamaterials can be applied to create very sensitive sensors, to achieve non-reciprocal signal communications and to develop new techniques in quantum imaging. (Please click here for Prof. Li’s biography)
Dr Jäck’s research focuses on the fabrication and characterization of novel quantum materials that could facilitate energy-efficient electronic devices and new types of quantum computers. Placed at the interface of condensed matter physics and material science, his research aims to augment the microscopic interactions between charge carriers and magnetic moments through judicious materials design resulting in novel quantum phenomena. To this end, Dr Jäck combines thin film material growth using molecular beam epitaxy with the microscopic and macroscopic material characterization using scanning tunnelling microscopy and electrical transport measurements, respectively. Developing novel microscopy methods to study charge carrier dynamics with high spatial and temporal resolution, Dr Jäck’s ultimate research goal is exploring new frontiers in quantum materials research. (Please click here for Dr Berthold Jäck’s biography)
Apart from Prof. Li and Dr. Jäck, The Croucher Foundation has also awarded Croucher Tak Wah Mak Innovation Awards 2022 and Croucher Senior Research Fellowships 2022 and 2023 to seven other distinguished scholars from The Chinese University of Hong Kong (CUHK), The University of Hong Kong (HKU) and The Hong Kong Polytechnic University (PolyU), for their outstanding scientific research achievements. Click here for more information on the awards.
The Hong Kong University of Science and Technology (HKUST) and the University of Southampton will strengthen their partnership and launch a new Dual Master Program of Science in global marine resources management next year.
Offering a multi-cultural and cross-continental learning experience, students admitted to this unique one-year program will spend the first semester in Southampton and the second as well as the summer at HKUST. Students will not just gain knowledge and first-hand experience in marine ecosystems across the two continents, but also get to develop professional network in Hong Kong, Southampton and beyond. They will graduate with qualifications from both universities.
Blue economy has become an emerging hot topic in the past decade. Governments worldwide including China and the United Kingdom have rolled out initiatives and proposals on how to use ocean resources for growth in a sustainable way. In this program, students will not only learn the contrasting marine ecosystems and geological processes in temperate and subtropical regions across two continents, but also the skillsets spanning from computational data analysis, pollution monitoring and control, to conservation and sustainability, environmental policy, environmental impact and risk assessment.
Professionals with this level of training are highly sought after. The program will prepare students for a wide range of career opportunities spanning research and education in marine and environmental science in both public and private sectors as well as non-governmental organizations. It will also pave the way for further studies in the fields of marine resources management and exploration, oceanography and environmental conservation.
At the virtual partnership signing ceremony yesterday, Professor Jane FALKINGHAM, Vice-President of International and Engagement at the University of Southampton said, “I’m delighted to be involved in this ceremony today. This agreement forges a key academic alliance between two world leading universities in marine science in Europe and Asia. It enables both universities to blend their respective faculty experience and expertise and establishes a dynamic platform for further academic and research collaborations.”
Prof. WANG Yang, Vice-President for Institutional Advancement at HKUST, said he is delighted to see HKUST joining forces with the University of Southampton as its marine resource research is internationally recognized. He said, “This collaboration will allow us to train professionals in a multicultural and cross-national setting, leveraging on each of our advantages in cutting-edge ocean science research and the unique geographic locations. The joint Master’s program enables students to learn scientific, technological, socioeconomic and political issues that are involved in the exploration, management and conservation of marine resources in temperate and subtropical regions.”
Dr. Charlie THOMPSON, Co-Program Director at the University of Southampton said, “This program provides an exciting balance of fundamental learning and hands-on experience, as well as developing core research skills alongside experts from across continents – a unique opportunity for those who want to work with a truly global focus.”
Prof. Stanley LAU, Co-Program Director and Acting Head of HKUST’s Department of Ocean Science said, “Three years after our introduction of Hong Kong’s first undergraduate degree in ocean science and technology, we are very happy to launch Hong Kong’s first Dual Master’s Degree Program in Global Marine Resources Management in collaboration with the University of Southampton. Through the provision of in-person learning activities in the multicultural environments in Hong Kong and the UK, we will continue to strengthen our commitment to nurturing professionals with cross-disciplinary knowledge, global vision and international professional network to tackle complex issues in marine resources management.”
The program is the first double degree partnership between HKUST and the University of Southampton. The first cohort of MSc Global Marine Resources Management students will commence their studies in September 2023.
Over the years, HKUST and the University of Southampton have forged various collaborations on academic and scientific exchange and knowledge transfer, including a Student Exchange Agreement between the two institutions in areas of science and engineering.
For more program details and admission requirements, please visit: https://mscgmrm.org/
About the Hong Kong University of Science and Technology
The Hong Kong University of Science and Technology (HKUST) (https://hkust.edu.hk/) is a world-class research intensive university that focuses on science, technology and business as well as humanities and social science. HKUST offers an international campus, and a holistic and interdisciplinary pedagogy to nurture well-rounded graduates with global vision, a strong entrepreneurial spirit and innovative thinking. Over 80% of our research work were rated “Internationally excellent” or “world leading” in the Research Assessment Exercise 2020 of Hong Kong’s University Grants Committee. We were ranked 3rd in Times Higher Education’s Young University Rankings 2022, and our graduates were ranked 30th worldwide and among the best from universities from Asia in Global Employability University Ranking and Survey 2022. As of 2022, HKUST members have founded 1,645 active start-ups, including 9 Unicorns and 7 IPO companies, generating economic impact worth over HK$400 billion. InvestHK cited QS World University Rankings by Subject 2021 to demonstrate the performance of five world’s top 100 local universities in several innovation-centric areas, among which HKUST ranked top in four engineering and materials science subjects.
About the University of Southampton
The University of Southampton drives original thinking, turns knowledge into action and impact, and creates solutions to the world’s challenges. We are among the top 100 institutions globally (QS World University Rankings 2022). Our academics are leaders in their fields, forging links with high-profile international businesses and organisations, and inspiring a 22,000-strong community of exceptional students, from over 135 countries worldwide. Through our high-quality education, the University helps students on a journey of discovery to realise their potential and join our global network of over 200,000 alumni. www.southampton.ac.uk
(This article was originally published on EurekAlert! on November 18, 2022)
Damages to the central nervous system (CNS), for example in the case of spinal cord injury, can result in permanent loss of sensory and motor function. It is because the severed axons are unable to regenerate. As of today, there are very limited options to help these patients regain their motor abilities. Scientists have been exploring ways to enable the regeneration of severed axons, with a view to developing viable treatments in the long term.
In a study using mice, a research team led by Cheng Associate Professor Kai LIU of the Division of Life Science, the Hong Kong University of Science and Technology (HKUST), untangled some of the complexities in the regeneration of severed axons. They found that the deletion of PTPN2, a phosphatase-coding gene, in neurons can prompt axons to regrow. When combined with the type II interferon IFNγ, it can further accelerate the process and boost the number of axons regenerated. The results have recently been published in the scientific journal Neuron.
The human nervous system is composed of two parts, namely the central and peripheral nervous systems. Unlike the central nervous system, peripheral nerves have stronger ability to regrow and repair by themselves after injury. Scientists have yet to fully understand the relationship between this self-repair and the intrinsic immune mechanism of the nervous system. Two mysteries the team wanted to resolve were how immune-related signaling pathways affected neurons after injury, and whether they could enhance axonal regeneration directly.
This study investigated whether the signaling pathway IFNγ-cGAS-STING had any role in the regeneration process of peripheral nerves. Researchers found that peripheral axons could directly modulate the immune response in their injured environment to promote self-repair after injury.
In previous research, Prof. Liu’s team had already demonstrated that elevating the neuronal activity and regulating the neuronal glycerolipid metabolism pathway could boost axon regenerative capacity. The current study is providing further insights into the search of treatment solutions for challenging conditions such as spinal cord injuries, with one possible option being the joining of several types of different signaling pathways.
The co-first authors of this project are Drs. Xu WANG and Chao YANG of HKUST. The work was done in collaboration with Prof. Zhong-Yin ZHANG of Purdue University alongside Profs. Ruohao WU, and Peiyuan QIAN, Jiguang WANG of HKUST.
(This article was originally published on EurekAlert! on November 16, 2022)
CO2 in the deep Earth may be more active than previously thought and may have played a bigger role in climate change than scientists knew before, according to a study by the Hong Kong University of Science and Technology (HKUST).
The research, led by Prof. PAN Ding, looked into the dissolution of CO2 in water, which has significant implications on ways to reduce the return of carbon from underground to the atmosphere.
The vast majority of the Earth’s carbon is buried in its interior. That deep carbon influences the form and concentration of carbon near the surface, which can in turn impact global climate over geologic time. It is therefore important to assess how much carbon lies in deep reservoirs hundreds of kilometers underground.
“Existing research has focused on carbon species above or close to the Earth’s surface. However, more than 90 percent of the Earth’s carbon is stored in the crust, mantle, and even core, which is poorly known,” Prof. Pan explained.
Using first-principles simulations in physics, his team found that CO2 may be more active than previously thought in Earth’s deep carbon cycle, which largely influences the carbon transport between Earth’s deep and near-surface reservoirs.
Confining CO2 and water in suitable nanoporous minerals may enhance the efficiency of underground carbon storage, the study found. It suggests that in carbon capture and storage efforts, turning CO2 together with water into rocks under nanoconfinement offers a secure method to permanently store carbon underground with a low risk of return to the atmosphere.
The findings have been published recently in the international academic journal Nature Communications.
“Dissolving CO2 in water is an everyday process, but its ubiquity belies its importance. It has great implications for Earth’s carbon cycle, which deeply affect global climate change over geologic time and human energy consumption,” Prof. Pan said.
“It is an important step forward to understand the unusual physical and chemical properties of aqueous CO2 solutions under extreme conditions.”
Previous studies focused on properties of dissolved carbon in bulk solutions. But in deep Earth or underground carbon storage, aqueous solutions are often confined to the nanoscale in pores, grain boundaries, and fractures of Earth’s materials, where spatial confinement and interface chemistry may make the solutions fundamentally different.
“The carbon-bearing fluids can be as deep as hundreds of kilometers, which are impossible to directly observe. Experimentally, it is also very challenging to measure them under extreme pressure-temperature conditions found in deep Earth,” he said.
Prof. Pan is an associate professor of physics and chemistry at the university. The team also comprises doctoral students Nore Stolte and Rui Hou. They ran simulations to study the reactions of CO2 in water in nanoconfinement.
Comparing the carbon solutions nanoconfined by graphene, an atomic layer of graphite, and stishovite – a high pressure SiO2 crystal – with those dissolved in bulk solutions, they found that CO2 reacted more in nanoconfinement than in bulk.
The research is paving the way for studies into more complicated carbon reactions in water in deep Earth, such as the formation of diamonds, abiogenetic petroleum origin, and even deep life. As the next step of the study, the team hopes to explore if carbon may further react to form more complicated molecules like organic matter.
Prof. Pan develops and applies computational and numerical methods to understand and predict the properties and behavior of liquids, solids, and nanostructures from first principles. With the help of high-performance supercomputers, his team seeks answers to urgent and fundamental scientific questions relevant to sustainable development, such as water science, deep carbon cycle, and clean energy.
(This article was originally published on EurekAlert! on November 1, 2022)
Aging, and the struggle against it, has long been a popular theme in classic and modern literature in human history. From the ill-fated Qin Shi Huang’s expedition to the sea searching for eternal life to Count Dracula’s popularity in the West, aging is a mystery that has captured the world's imagination for thousands of years and yet remains unsolved.
In an exciting development, a HKUST research group led by Prof. Tom CHEUNG, S H Ho Associate Professor of Life Science, whose work focuses on studying muscle stem cells (MuSCs), which play a key role in muscle repair, has discovered a method to identify the aging MuSC, based on its chromatin signature. Aging MuSCs, unlike their younger counterparts, show reduced stemness (the ability to become new stem cells or turn into specialized cells to replace damaged tissues). If the chromatin signature of an aging cell can be reverted to that of a young cell, then the process of cellular aging, and, in this case, the aging of skeletal muscle tissue—could be put on hold or even reversed.
Their findings were published recently in the open-access journal iScience by Cell Press.
“The regulation of chromatin accessibility is critical for cell fate decisions,” said Prof. Cheung. “Changes in the chromatin state can lead to dysregulation of gene expression. In our study, we were able to identify the chronically activated chromatin state as a hallmark of stem cell aging, which could be a target for developing anti-aging strategies.”
Chromatin, a complex of DNA that wraps around histones to maintain DNA in its proper architecture, undergoes rapid changes in its structure in response to the extrinsic environment. As a continuation of their previous study, the team pre-fixed muscle stem cells in the mouse to obtain quiescent cells (dormant cells that will activate to repair injured muscle) and obtained their gene and chromatin signatures, in which they then compared the chromatin accessibility over time.
“We showed that the chromatin environment of young muscle stem cells is very compact during quiescence, becomes highly accessible on early activation, and gradually re-establishes the compact state after long-term regeneration. However, aged muscle stem cells lose their ability to maintain such a compact chromatin environment during quiescence,” said Dr. Anqi Dong, first author of the study and a former member of Prof. Cheung’s research group who is now a Postdoctoral Fellow at the Université libre de Bruxelles.
Many possibilities are waiting to be unearthed now that scientists have gained a better understanding of what happens to an aging cell, opening a variety of avenues for anti-aging strategies to be pursued further.
“Have we solved the mystery of aging? Yes, but not quite,” noted Prof. Cheung. “If we can find chromatin-modifying regulators that are downregulated in aged stem cells, these will be potential targets to prevent aging by restoring their expression. As we are able to make a clear comparison between the chromatin states of young and old muscle stem cells, we have also identified target locations that are specifically accessible in young muscle stem cells. If the accessibility of those regions can be maintained during aging, we may be able to find ways to keep cells young and healthy longer.”
“Our current study describes the changes in chromatin accessibility during stem cell isolation and activation, but the journey has just begun,” said Prof. Cheung. “We look forward to further investigating the mechanisms that alter the chromatin state during muscle stem cell isolation and activation, and it is important we conduct the same study in vivo for more insights.”
Changes in aging stem cells
Congratulations to two faculty members from the School of Science who have been recognized by the National Natural Science Foundation of China (NSFC)! Prof. Zhigang BAO, Associate Professor in the Department of Mathematics, and Prof. Ding HE, Assistant Professor in the Department of Ocean Science, both named NSFC Excellent Young Scientists (Hong Kong and Macau), have received a funding of RMB 2,000,000 to support their scientific research projects for a period of 3 years. Only 25 projects across Hong Kong and Macau have been awarded this highly competitive fund this year.
Prof. Zhigang BAO has been awarded with his research project titled “Random Matrix Theory and its applications in Statistics”. It focuses on studying the spectral theory of large dimensional random matrices. It would investigate the limiting behavior of eigenvalues and eigenvectors of random matrix models arising from free probability, disordered quantum system, and multivariate statistics.
Prof. BAO’s research:
Prof. Ding HE has been awarded with his research project titled “Organic Geochemistry of Estuaries and Coasts”. Estuaries and coasts, linking land and ocean, play a critical role in global carbon cycle, but traditional methods cannot resolve the carbon source/sink processes. Based on molecular biomarkers, stable isotopes, ultra-high resolution mass spectrometry, and big-data techniques, Prof. HE focuses on the organic carbon (OC) cycling in estuaries and coasts. In particular, he determined the OC sources, biogeochemical processes, and the underlying controlling factors during the Anthropocene and published over 50 manuscripts in international journals. With support of the fund, Prof. HE and his group members aim to reveal the OC burial process, carbon sequestration capacity and control factors from the molecular level, serving the national and Hong Kong government’s carbon peak, and carbon neutral policy needs.
To our best knowledge, Prof. HE is the first awardee of this fund in the field of Oceanography (especially in Chemical Oceanography) in Hong Kong and Macau.
The organic carbon cycling in estuaries and coasts (partially reorganized from Bauer et al., 2013)
The DREAM (Data-driven Research for Exploring Aquatic geocheMisty) group in Department of Ocean Science, HKUST (www.helabhkust.com)
Prof. Haipeng LU, Assistant Professor in the Department of Chemistry has been awarded the 2022 National Natural Science Foundation of China (NSFC) Young Scientists Fund. This prestigious fund offers support to young academics and encourages them to focus on a self-chosen area for basic research. It helps foster the young scholars with outstanding achievement on the international science frontiers.
Prof. Haipeng LU is awarded for his research project titled “Development of highly luminescent chiral hybrid semiconductors”. The development of polarized light sources plays an essential role in the modern display industry and future technologies including 3D display, quantum computing and sensing, and information processing. Current materials and approaches that generate polarized light have serious limitations including excessive cost, complex infrastructure, and low sensitivity and resolution. This project is focused on the development of an emerging family of hybrid semiconductors that break the time-reversal symmetry via structural chirality. These materials have the potential to emit high purity of circularly polarized luminescence with high efficiency. This project is to build such a synthetic roadmap for these fascinating materials.
Congratulations to Prof. LU on receiving the 2022 NSFC Young Scientists Fund!
Prof. Haipeng LU (fourth from the left) and his group members