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A simple, clean and organic method for creating plastics from greenhouse gases P. 48 THE FIRST GENOME OF A CORAL REEF FISH

A fish’s genome may illustrate how reef fish adapt to challenges in the Red Sea. P. 14

A MODERN WAY TO HEAL OLD WOUNDS

Smart bandage technology provides updates through a mobile phone app. P. 27

MODELING DUST FLOW FROM AFRICA TO ARABIA High-resolution modeling to observe violent dust sandstorms. P. 62

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608 NANOMETERS

The first-ever orange semiconductor laser, fabricated at KAUST, has a wavelength of 608 nanometers. The novel method for creating this new color is another step forward in making laser lighting as ubiquitous and as useful as traditional lighting. Laser lighting is up to 80 percent more energy-efficient than LED lights and has potential applications ranging from agriculture to wireless internet and underwater communications.

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ear Friends, For over 30 years, I have had the pleasure of serving in higher education, and in every experience I have come to value the power of people, the importance of a culture of excellence and the critical role that science and technology play in society. At KAUST, we are committed to these distinctive attributes through our people and purpose: to advance science and technology through distinctive and collaborative research integrated with graduate education. When my wife Carol and I arrived at KAUST, our focus was simple: encourage great minds to think beyond what is possible. Throughout our careers at places like Georgia Tech and Caltech, we witnessed the general public’s excitement in science and technology fueled by exploration, discovery and innovation. I believe there is no greater reward than inspiring people to pursue novel ideas and solutions. The people of KAUST are doing just that—collaborating together to expand our fundamental understanding of the world through new knowledge. This makes KAUST a destination for talented people whose individual impact is amplified in a collective group of thinkers and makers who share a drive for creative new discoveries. We embody a “state of mind” that

I believe distinguishes great research universities. At KAUST, this state of mind motivates our people to think of and offer new possibilities in science and technology for the people of Saudi Arabia and the world. In the coming pages, you will read examples of research—from geophysical studies of the Earth to flexible electronics with the potential for diagnosing brain disorders to polymers specifically designed

“KAUST is a destination for talented people whose individual impact is amplified in a collective group of thinkers and makers who share a drive for creative new discoveries.” to remove harmful greenhouse gases from the atmosphere. Throughout this edition, I am confident that you will experience the passion and purpose of our people as they pursue excellence in science and engineering. This passion inspires me in our ongoing commitment to a culture of excellence in research and education. As we embark on the eighth year of our

Jean-Lou Chameau President university, our foundation is strong. Our contributions are beginning to capture the world’s attention and in the coming decade, our true impact will be realized. We remain most proud of our over 1,000 graduates who are spreading our vision of science and technology to the Kingdom and the world. To continue accelerating KAUST’s impact, we must each embrace and embody the university’s unique state of mind and culture of excellence and innovation. I hope you enjoy this glimpse into our aspirational state of mind. Yours in discovery, Jean-Lou Chameau President

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HIGHLIGHTS LIGHTING UP THE FUTURE

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MEMORY DEVICE SEES THE LIGHT

Ferroelectric tunnel junction promises low-power, highdensity data storage.

Nanocrystals could help combine lighting and communications systems into one.

TACKLING CLIMATE CHANGE

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Sophisticated statistical methods can detect ozone pollution hotspots and monitor instrument failure.

New sensor design paves the way for safer and more effective brain monitoring.

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Graphene quantum dots can improve the efficiency of silicon solar cells.

THE SIGNIFICANCE OF SEAWEED

Carbon storage by coastal macroalgae is a significant but neglected aspect of the global carbon budget.

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The efficient purification of propylene using a fine-tuned porous material delivers advances in petrochemical production.

GENTLE SENSORS FOR DIAGNOSING BRAIN DISORDERS

Smart bandage technology provides instant updates on the condition of chronic wounds via a mobile phone app.

UTILIZING A BROADER SHARE OF THE SOLAR SPECTRUM

A CLEAN SEPARATION

TECHNOLOGY IMPROVING HEALTHCARE

A MODERN WAY TO HEAL OLD WOUNDS

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STEP INTO THE WHITE LIGHT FOR FASTER COMMUNICATION

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AGAINST THE FLOW OF DRUG RESISTANCE

Certain bacteria-based water treatment systems may help prevent the spread of antibiotic resistance.

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PUSHING THE LIMITS

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BARLEY THAT THRIVES IN SALTY SOILS

Mapping the genetics underlying barley yields helps pinpoint mutations responsible for increasing the crop’s salt tolerance.

THE FIRST GENOME OF A CORAL REEF FISH

A genome for the blacktail butterflyfish may illustrate how reef fish adapt to challenging conditions in the Red Sea.

NOVEL METHODS, IMPORTANT APPLICATIONS COPOLYMER MEMBRANES TOUGHENED UP

HELPING COMPUTERS TO SEE WHO WE REALLY ARE

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Innovative chemistry has produced synthetic membranes with improved properties for industry, research and biomedicine.

Algorithms that train computers to automatically detect human activity in videos can improve online searches and real-world surveillance systems.

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A GOLDEN REPLACEMENT

High-resolution modeling improves understanding of dust flow from Africa across the Red Sea toward the Arabian Peninsula.

Surface deformation caused by magma rising within the crust may in turn have prevented a volcanic eruption in Saudi Arabia.

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Metabolic route explorer helps to optimize the pathways for artificial biosynthesis of valuable products.

THE EARTH OBSERVATORY

SURFACE FRACTURES AS MAGMA MOVES

Images from a high-speed camera reveal a microbead formation process during the vapor explosion of liquid metal dropping into a pool of water.

EXPLORING ARTIFICIAL BIOSYNTHESIS

Altering a single atom in a silver nanocluster considerably changes its properties, creating an exciting opportunity for design of these clusters.

MODELING DUST FLOW FROM AFRICA TO ARABIA

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FIERY EXPLOSIONS OF HOT METAL ON WATER

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47 MAKING SPACE FOR CLIMATE SIMULATIONS

A statistics-based data compression scheme cuts data storage requirements for large-scale climate simulations by as much as 98 percent.

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TRILLION GRAMS KAUST scientists discovered that 173 trillion grams of carbon is sequestered annually by coastal seaweed. The role of seaweed and other marine vegetation in the carbon cycle is a significant but previously underrepresented aspect of the global carbon budget. Better quantification of the global carbon budget is critical in the understanding remediation of the harmful effects of gases.

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A BLOSSOMING FIELD OF PRECISION AGRICULTURE Novel technologies that can help determine crop health, water use and yields could herald a revolution in sustainable agriculture.

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A DEADLY DELIVERY FOR BREAST CANCER

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THE FIRST GENOME OF A CORAL REEF FISH

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BARLEY THAT THRIVES IN SALTY SOILS

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RHYTHM ADJUSTMENT FOR CO2 RISE

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COPOLYMER MEMBRANES TOUGHENED UP

Zinc oxide (ZnO) nanoparticles may help destroy difficult-to-treat triple-negative breast cancer tumors.

A genome for the blacktail butterflyfish may illustrate how reef fish adapt to challenging conditions in the Red Sea.

Mapping the genetics underlying barley yields helps pinpoint mutations responsible for increasing the crop’s salt tolerance.

Evolutionary alterations to circadian rhythm genes help reef fish adapt to the higher levels of carbon dioxide of future oceans.

Innovative chemistry has produced synthetic membranes with improved properties for industry, research and biomedicine.

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HYDROCARBONS FROM THE SKY

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AGAINST THE FLOW OF DRUG RESISTANCE

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LEUKEMIA TREATMENT OFFERS HOPE

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THE SIGNIFICANCE OF SEAWEED

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GENOMICS: THE INTERSECTION OF FOLDING AND FUNCTION

Ocean cruise studies the input of toxic organic chemicals from the atmosphere into the ocean.

Certain bacteria-based water treatment systems may help prevent the spread of antimicrobial drug resistance.

Antibodies directed against cancer stem cells could help patients with acute myeloid leukemia.

Carbon storage by coastal macroalgae is a significant but neglected aspect of the global carbon budget.

The dynamic three-dimensional organization of chromosomal structure can profoundly influence plant gene expression.

DISCOVER MORE RESEARCH AT discovery.kaust.edu.sa

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TECHNOLOGY SEARCH FOR RELATIONSHIPS

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GENTLE SENSORS FOR DIAGNOSING BRAIN DISORDERS

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MAKING SPACE FOR CLIMATE SIMULATIONS

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UTILIZING A BROADER SHARE OF THE SOLAR SPECTRUM

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STEP INTO THE WHITE LIGHT FOR FASTER COMMUNICATION

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HELPING COMPUTERS TO SEE WHO WE REALLY ARE

A sketch-based query for searching for relationships among objects in images could enhance the power and utility of image search tools.

New low-cost sensor design paves the way for safer and more effective brain monitoring.

A statistics-based data compression scheme cuts data storage requirements for large-scale climate simulations by as much as 98 percent.

Graphene quantum dots can improve the efficiency of silicon solar cells to make them more commercially attractive.

Nanocrystals that generate white light could help combine lighting and communications systems into one.

Algorithms that train computers to automatically detect human activity in videos can improve online searches and real-world surveillance systems.

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A MODERN WAY TO HEAL OLD WOUNDS

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ENHANCING UNDERSTANDING OF GENETIC REGULATION

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EXPLORING ARTIFICIAL BIOSYNTHESIS

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KEEPING POLLUTION UNDER CONTROL

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SHARING MOVEMENT AIDS LEARNING

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GETTING A HANDLE ON EXTREMES

Smart bandage technology provides instant updates on the condition of chronic wounds through a mobile phone app.

Researchers round up clues to track down enhancers that affect genetic regulation.

Metabolic route explorer helps to optimize the pathways for artificial biosynthesis of valuable products.

Sophisticated statistical methods can detect ozone pollution hotspots and monitor instrument failure.

Automated learning of an individual’s movement patterns shared over mobile and social networks could help us to connect better.

A statistical model that accurately describes rainfall at both extremes allows for more reliable predictions of flood and drought risk.


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A GOLDEN REPLACEMENT

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CATALYSIS STEPS INTO THE THIRD DIMENSION

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FIERY EXPLOSIONS OF HOT METAL ON WATER

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MEMORY DEVICE SEES THE LIGHT

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A CLEAN SEPARATION

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SEE-THROUGH CIRCUITRY

Altering a single atom in a silver nanocluster considerably changes its properties, creating an exciting opportunity to design these clusters.

Nonsurfactant polymers template produces a highly porous, three-dimensional inorganic crystal to enhance catalysis and separation.

Images from a high-speed camera reveal a microbead formation process during the vapor explosion of liquid metal dropping into a pool of water.

Ferroelectric tunnel junction controlled by light promises low-power, high-density data storage.

The efficient purification of propylene using a fine-tuned porous material delivers advances in petrochemical production.

A simple process for atom-by-atom deposition paves the way to low-cost, high performance transparent electronic materials.

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POLLUTION TO PLASTICS

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ELECTRIC FIELDS TAME THE FLAME

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SEISMIC ECHO TURNS INTO SUPER-RESOLUTION IMAGES

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SURFACE FRACTURES AS MAGMA MOVES

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MODELING DUST FLOW FROM AFRICA TO ARABIA

A clean, green, metal-free approach to making high-performance polycarbonates from CO2.

A clearer understanding of how flame is affected by electric fields paves the way for advanced electrically assisted combustion technology.

A signal processing technique that makes use of seismic echoes is able to image subsurface geology at unprecedented resolution.

Surface deformation caused by magma rising within the crust may in turn have prevented a volcanic eruption in Saudi Arabia.

High-resolution modeling improves understanding of dust flow from Africa across the Red Sea toward the Arabian Peninsula.

KAUST DISCOVERY IS PUBLISHED FOR THE KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY (KAUST) BY THE PARTNERSHIP AND CUSTOM MEDIA UNIT OF NATURE RESEARCH, PART OF SPRINGER NATURE. KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY (KAUST) THUWAL 23955-6900 – KINGDOM OF SAUDI ARABIA EMAIL: MEDIA@KAUST.EDU.SA - WEB: WWW.KAUST.EDU.SA NATURE RESEARCH THE CAMPUS – 4 CRINAN STREET – LONDON, N1 9XY, UK EMAIL: NATURE@NATURE.COM - WEB: WWW.NATURE.COM

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A BLOSSOMING FIELD OF PRECISION AGRICULTURE Novel technologies that can help determine crop health, water use and yields could herald a revolution in sustainable, precision agriculture.

The collection of a wide range of datasets from fields can help reduce water use and boost the production of highquality crop yields.

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ew methods of monitoring irrigation, crop health and yields are being pioneered by KAUST in order to generate and safeguard sustainable food supplies and better manage global water resources. On a global scale, agriculture accounts for around two-thirds of freshwater use, a figure that rises to 85 percent in arid regions such as the Kingdom of Saudi Arabia. However, the amount of water taken from groundwater aquifers, rivers and lakes to supply irrigation needs is rarely monitored, putting future food and water security under threat in the face of changing climate and growing populations. Matthew McCabe, an associate professor in the University’s Water Desalination and Reuse Center (WDRC), leads a research team undertaking groundbreaking research that monitors crop health and water use more closely than ever before through data collected by novel technologies like unmanned aerial vehicles (UAVs) and nano-satellites1. “My group focuses on research related to hydrology, which is the understanding and quantification of the interactions of water with the landscape,” McCabe said. “We generally use water quite inefficiently, but this is especially true in agriculture. It is a problem that stems from poor irrigation techniques and uninformed crop management. Finding ways to improve this is critically important if we’re to achieve more sustainable use and management of global water resources.” For farmers across the world, a key goal is to generate high-quality, abundant crops. To do this, farmers need accurate real-time information on crop health and productivity that ideally comes down to monitoring individual plants on a daily basis. This information would enable them to make informed decisions about whether plants are receiving too little or too much water, whether they are suffering from disease and whether they are thriving in specific soils. The

information can be gathered by monitoring factors such as biomass (the quantity or weight of a crop in a given area); leaf health and chlorophyll content (referring to pigments that make plants green); and transpiration (the water used by plants). McCabe is excited by the potential of new high-resolution data collection techniques that could transform the blossoming field of precision agriculture. “Trying to understand the fine-scale characterization of agricultural systems and optimize the inputs (water, fertilizer) to maximize the outputs is the basis of precision agriculture,” McCabe noted. “It is both an observation and a modeling problem. We can

“We generally use water quite inefficiently, but this is especially true in agriculture. Finding ways to improve this is critically important if we’re to achieve more sustainable use and management of global water resources.”

use satellites—and now UAVs—to tell us so much about the state of a crop. For example, we developed a collaboration with a Silicon Valley startup company called Planet that is launching hundreds of very small satellites to monitor the entire Earth’s surface on a 3 to 5 meter scale. This gives us access to high-resolution satellite data that can be used to provide incredible detail of the land surface.” Rasmus Houborg, a research scientist at KAUST, recently developed a machine learning technique that can take information from the RGB (red-green-blue) color images collected by Planet’s nanosatellites and combine this information with other satellite data to create Normalized Difference Vegetation Index (NDVI) maps. NDVI is a tool that can be used to infer the amount of healthy green vegetation in a specific area and is a gauge of how well a crop is functioning. These new NDVI maps represent one of the highest resolution NDVI data sets available from space. Such revolutionary datasets have the potential to transform agriculture management on a global scale. Such revolutionary datasets have the potential to transform agriculture management on a global scale. In addition, Matthew McCabe, an associate professor in the University’s Water Desalination and Reuse Center (WDRC), leads a research team undertaking groundbreaking research that monitors crop health and water use more closely than ever before through data collected by novel technologies like unmanned aerial vehicles (UAVs) and nano-satellites1. “This data is of interest not just to farmers but also to government agencies that are responsible for water allocations (or resources), aid agencies looking to assess food production forecasts and even traders who hedge bets on global crop yield estimates,” McCabe said. “The scope and potential that such technologies have is amazing. We are witnessing an exciting revolution in Earth observation that will change the way we manage our food and water resources.” JANUARY 2017

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HYDROCARBONS FROM THE SKY Ocean cruise studies input of PAHs from the atmosphere into the ocean.

At sea on the Malaspana 2010 Circumnavigation Expedition. 10


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oxic organic chemicals known as polycyclic aromatic hydrocarbons (PAH) are released during the burning of carbon-based organic materials where not all of the carbon is converted into carbon dioxide. This incomplete combustion occurs whenever fossil fuels or other organic material burns in air. KAUST researchers have helped evaluate how much of these pollutants are deposited from the atmosphere into the ocean worldwide1, and their results challenge current thinking about the global carbon budget.

scientists first calculated the dynamics of the part of the global carbon cycle associated with the combustion of organic matter. “The assumption must have been made that the carbon in fossil fuels used by humans was combusted all the way to carbon dioxide,” he said. The realization that this is wrong will change our fundamental understanding of the carbon cycle, as scientists cannot currently account for the fate of the carbon in fossil fuels burned by tracing only carbon dioxide. “Scientists also need to investigate

“The magnitude of polycyclic aromatic hydrocarbons inputs to the ocean is so large that we must reconsider our understanding of the global ocean carbon budget.” “The magnitude of PAH inputs to the ocean is so large that we must reconsider our understanding of the global ocean carbon budget,” said Professor Carlos Duarte from the KAUST Red Sea Research Center. There is a great variety of PAHs, but all have some of their carbon atoms bonded in linked six-carbon rings. They occur naturally in crude oil as well as being released when organic matter burns. As semi-volatile molecules, they leave the air to enter the ocean more readily than small volatile molecules. The researchers measured levels of 64 PAH compounds in seawater and air during the Malaspana 2010 Circumnavigation Expedition. The results indicate that the global input of PAH from the atmosphere into the ocean every year is around 20 times greater than the direct input caused by the Deepwater Horizon oil spill of 2010. Duarte explained that the results suggest a significant error was made when

the impact of such a high PAH input on ocean ecosystems and food webs,” added Duarte. PAHs are toxic to all organisms (including humans), and he emphasized that there is a need for further research to understand the fate of these inputs and to mitigate their impacts. The scale of the threat, however, may also offer an opportunity. Since PAHs are such significant and prevalent sources of organic carbon in the oceans, microbial communities in the water have been exposed to them over decades. This is long enough for some microbes to evolve the capacity to consume and degrade PAHs. Identifying the microbes that are most adept at consuming PAHs may assist in cleaning up oil spills and areas of chronic oil exposure. 1. González-Gaya, B., Fernández-Pinos, M-C., Morales, L., Méjanelle. L., Abad, E. et al. High atmosphere–ocean exchange of semivolatile aromatic hydrocarbons. Nature Geoscience 9, 438–442 (2016).

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A DEADLY DELIVERY FOR BREAST CANCER Zinc oxide (ZnO) nanoparticles may help destroy difficult-to-treat triple-negative breast cancer tumors.

Live cell imaging shows fluorescently labeled targeted ZnO nanoparticles (green) dissolving to release zinc ions (blue) within the intracellular environment of triple-negative breast cancer cells, activating cell death pathways (red).

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reast tumors that are socalled triple-negative are largely resistant to existing cancer drugs, giving patients an especially poor prognosis. KAUST researchers and collaborators are now exploring a potential therapeutic option for such tumors that is based on the tumor-specific effects of zinc oxide (ZnO) nanoparticles 1. Previous studies have shown that ZnO treatment can kill cancerous cells while leaving healthy cells intact. However, the mechanism is poorly defined; some data 12

suggest that ZnO particles are ingested by and dissolve within tumor cells, while other findings suggest that cells absorb free zinc released when these particles dissolve in the acidic tumor environment. In a study led by Jasmeen Merzaban, KAUST assistant professor of bioscience, and Alexandra Porter from Imperial College London, Ph.D. candidates Basma Othman and Ayman Abuelela used microscopy to observe what happened when triple-negative breast tumor cells were treated with ZnO. For comparison, they used both untargeted conventional

ZnO nanoparticles as well as targeted nanoparticles tagged with a peptide that specifically recognizes a protein found on the surface of cancer cells. The results unambiguously supported a model in which the nanoparticles are consumed by the cells before inducing cell death. “We were able to observe in real time the uptake of both classes of ZnO nanoparticles and confirm the subsequent rise in zinc ion concentrations within cells prior to their death,” said Merzaban. The targeted nanoparticles proved substantially more effective at killing triplenegative cells in culture, requiring lower doses of ZnO. However, the real-time imaging experiments also revealed considerable variability in the way individual cells respond to treatment, with some cells perishing quickly while others hung on. The researchers speculate that this heterogeneity might reflect the presence of relatively drug-resistant cancer stem cell subpopulations. “These cells are believed by many to be responsible for the relapse of cancer following traditional therapies such as chemotherapy,” noted Merzaban. Eliminating such cancer stem cells could be a major victory against hardto-treat tumors. The researchers are now exploring whether such cells are responsible for the heterogeneous response observed in their experiments, with an eye toward improving the efficacy of their approach. In parallel, Merzaban plans to initiate animal studies that might give better insights into the clinical applicability of ZnO. “We intend to use in vivo imaging tools to determine how effective these nanoparticles are at inducing the death of breast cancer cells in tumor mouse models,” she said. “We are very excited about the potential of these and other nanoparticles as part of the future of medicine.” 1. Othman, B.A., Greenwood, C., Abuelela, A.F., Bharath, A.A., Chen, S. et al. Correlative light-electron microscopy shows RGD-targeted ZnO nanoparticles dissolve in the intracellular environment of triple negative breast cancer cells and cause apoptosis with intratumor heterogeneity. Advanced Healthcare Materials 5, 1310-1325 (2016).

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AGAINST THE FLOW OF DRUG RESISTANCE Certain bacteria-based water treatment systems may help prevent the spread of antibiotic resistance.

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any wastewater treatment facilities rely on membrane bioreactors (MBRs) that use bacterial communities to consume and break down contaminants that make the water unsafe for reuse. Assistant Professor Peiying Hong and colleagues from the KAUST Water Desalination and Reuse Center examined how specific pollutants in water affect these bacteria and identified a potential edge for one particular class of membrane bioreactors1. The microbes within these bioreactors can be oxygen-consuming aerobic bacteria or anaerobic bacteria that do not require oxygen. Hong noted that the anaerobic membrane bioreactors are known to have significant advantages, including very stable bacterial populations that are more efficient at processing pollutants. They are also more cost-effective. Before Hong’s study, little was known about how the contents of wastewater, which include household chemicals, antibiotics and pharmaceuticals, affect the integrity of these different communities. “We examined the effects of these compounds on the microbial community structures of the two MBR systems, their gene expression and the presence of antibiotic-resistance genes,” said Hong. Her team tested two miniature membrane bioreactors with simulated wastewater spiked with defined amounts of common chemical pollutants. Both the anaerobic and aerobic communities changed over the course of exposure, with certain species becoming more or less abundant in each bioreactor. The researchers also observed population-level changes in the expression of genes that enable bacteria to break down

KAUST Ph.D. student Moustapha Harb collects a water sample from the anaerobic membrane bioreactor.

biological waste, although both bioreactors remained consistent over time. A potential concern over membrane bioreactors is that steady exposure to antibiotics in wastewater will promote the development of drug-resistance genes, which can in turn make their way into the environment. However, Hong’s team saw a clear advantage for the anaerobic system. “There were significantly lower antibiotic resistance gene levels compared to the aerobic system, even at similar antibiotic concentrations,” she said. These findings provide yet another strong argument for using anaerobic membrane bioreactors, and Hong is now investigating other potential benefits of the technology.

Some of her group’s priorities include investigating whether anaerobic systems have an advantage in eliminating microbes from wastewater and producing a more in-depth analysis of how individual pollutant compounds influence bioreactor behavior. “We hope to show that microbial communities in anaerobic systems are robust enough to adjust to high concentrations of organic micropollutants while achieving good water treatment efficacy,” Hong said. 1. Harb, M., Wei, C.H., Wang, N., Amy, G. & Hong, P.Y. Organic micropollutants in aerobic and anaerobic membrane bioreactors: Changes in microbial communities and gene expression. Bioresource Technolology 218, 882-891 (2016).

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A genome for the blacktail butterflyfish may illustrate how reef fish adapt to challenging conditions in the Red Sea.

THE FIRST GENOME OF A CORAL REEF FISH

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equencing the genome of an organism allows scientists to investigate its unique genetic makeup, its evolutionary links to other creatures and how it has adapted to its environment. KAUST researchers have sequenced the first coral reef fish genome of the blacktail butterflyfish (Chaetodon austriacus), an iconic Red Sea species considered to be an indicator species for coral health. While genome sequences already exist for well-established model species such as the zebrafish, which is commonly used in medical research, there are no genomes publicly available for natural populations of tropical reef fish. A team from KAUST, including Associate Professor in the Red Sea Research Center 14

Researchers at KAUST have sequenced the genome of a coral reef fish, the blacktail butterflyfish from the Red Sea, for the first time.


BIOLOGICAL AN D EN VIRON MEN TAL SCIEN CE AN D EN GIN EERIN G DIVIS IO N Michael Berumen, former postdoctoral fellow Joseph DiBattista and their colleagues, sought to fill this significant gap in fish genomic data. “The blacktail butterflyfish has one of the most restricted ranges of any butterflyfish species, and is largely concentrated in the northern and central Red Sea,” explained DiBattista. “Therefore, it is likely to have developed unique genomic adaptations to this environment.” Identifying these genetic mechanisms may also help predict how other marine organisms could adapt to challenging sea conditions in future. The team faced a considerable task when it came to sequencing the new genome, partly because they had no reference genomes from closely related fish to compare. They took portions of gill filaments from a wild butterflyfish and generated a mix of DNA fragments, which are also called reads. “We then undertook a series of steps to figure out which reads connected with each other and how they overlapped as a whole,” explained Berumen. “Imagine

trying to reconstruct a lengthy book from tiny segments consisting of a few hundred characters, each taken from a random part of that book. This very quickly becomes a computer science problem, since it would be impossible

“The blacktail butterflyfish is largely concentrated in the northern and central Red Sea. Therefore, it is likely to have developed unique genomic adaptations to this environment.”

Aranda’s group, also from the University’s Red Sea Research Center. Once the team had assembled the genome, they analyzed it to ensure it made sense; for example, by checking for the existence of genes previously identified in other organisms. Their final high-quality genome includes 28,926 protein-coding genes. The team hopes the genome will enable studies on the co-evolution of reef fish species and comparisons of gene sequences between closely related fish across the Indo-Pacific region. The genome may also help stem trading in wild reef fish because aquaculture specialists may eventually be able use the data to produce new aquarium-tolerant species to fulfill the market demand for decorative fish.

to do it manually. Most fish genomes consist of around a billion base pairs, or a book with a billion characters in our analogy!” Berumen sought the bioinformatics expertise of assistant professor Manuel

DiBattista, J. D., Wang, X., Saenz-Agudelo, P., Piatek, M. J., Aranda, M. & Berumen, M. L. Draft genome of an iconic Red Sea reef fish, the blacktail butterflyfish (Chaetodon austriacus): current status and its characteristics. Molecular Ecology Resources (2016).

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Antibodies that block CD44 could help destroy acute myeloid leukemia cells.

Antibodies directed against cancer stem cells could help patients with acute myeloid leukemia.

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n antibody drug that targets a surface marker on cancer stem cells could offer a promising new therapeutic approach for treating acute myeloid leukemia (AML), a form of blood cancer that affects an estimated 50,000 people in Saudi Arabia. The leukemia stem cells responsible for propagating the disease express a protein on their surface called CD44. Antibodies that block CD44 have been shown to trigger the stem cells to mature, leading to a reduction in the growth and proliferation of these stubbornly hard-totreat cells. However, it wasn’t clear how or why this happens. Jasmeen Merzaban and colleagues from KAUST studied the signaling pathways that change through treatment with a CD44-directed antibody1. Working with both human AML cell lines and a mouse model, the researchers showed that inhibiting CD44 with the antibody led to a decrease in the expression of 16

two central pathways implicated in the aberrant growth of cancer cells: the PI3K (phosphoinositide 3-kinase) and the mTOR (mammalian target of rapamycin) pathways. The antibody notably blocked both of the structurally distinct complexes that include mTOR. That is significant because a complete shutdown of mTOR signaling is probably needed to disrupt the multiple feedback loops that can fuel cancer growth, and drugs that only inhibit one of these complexes have failed in the past to demonstrate a therapeutic benefit for patients with AML.

“The interesting thing about CD44 antibody treatment is that it is able to induce differentiation of many more AML subtypes.”

inhibitor. In her team’s hands, it encouragingly doesn’t seem to have toxicity issues. “We show that the anti-CD44 antibody used for our studies had no effect on normal blood cells,” said Samah Gadhoum, a research scientist in Merzaban’s lab group at KAUST and the first author of the study. “However, more work is needed to carefully determine the effect of these antibodies on other cells and other cellular functions within the body.” Merzaban, Gadhoum and their colleagues are now running follow-up experiments. For now, though, all their results “support the use of anti-CD44 antibodies for the treatment of AML as a differentiation-inducing therapy,” said Merzaban. As an added bonus, unlike other therapies that seem to work only for certain forms of the disease, “the interesting thing about CD44 antibody treatment is that it is able to induce differentiation of many more AML subtypes,” said Merzaban.

“A growing body of evidence suggests that a broader inhibitor would result in a more potent therapeutic effect,” said Merzaban. An anti-CD44 drug like the one tested by Merzaban might just be that broad

Gadhoum, S.Z., Madhoun, N.Y., Abuelela, A.F. & Merzaban, J.S. Anti-CD44 antibodies inhibit both mTORC1 and mTORC2: A new rationale supporting CD44-induced AML differentiation therapy. Leukemia (2016) 30, 2397–2401; doi:10.1038/ leu.2016.221

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BARLEY THAT THRIVES IN SALTY SOILS Mapping the genetics underlying barley yields helps pinpoint mutations responsible for increasing the crop’s salt tolerance.

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ur capacity to feed the world’s growing population will be greatly improved by developing crops able to tolerate higher soil salinity and saltwater irrigation. KAUST researchers are leading the quest to pinpoint the genetic controls of salt tolerance in crops and recently completed the first large-scale genetic mapping study of barley plants in the field. Mark Tester, KAUST professor of plant science, Ph.D. student Stephanie Saade and colleagues from the University’s Biological and Environmental Science and Engineering Division chose barley as their genetic model because it is the most salt-tolerant of the cereal crops. They also had access to high-quality genome sequencing data for a European strain called Barke, which they used as the mother line for their field study. “We used a nested association mapping (NAM) population of barley plants,” explained Tester. “A NAM is a series of small populations with one line constant across them. In our NAM, Barke, the common mother line, represented about 75 percent of the genome of each plant. We used 25 different father lines, strains of wild barley from fertile Arabian areas known to exhibit higher salt tolerance than commercial strains.” This carefully designed genetic structure developed by collaborator Klaus Pillen from the University of Halle (Germany) brought together high genetic diversity from the 25 fathers while remaining statistically powerful because of the constant mother line. The substantial field site at the International Center for Biosaline Agriculture in Dubai allowed the team to bring the plants to full maturity. “Our unique site had deep sandy soil

KAUST Ph.D. student Stephanie Saade at the field site where the team trialed multiple lines of barley generated from the same mother line but with different fathers.

and used saltwater drip irrigation so we could maintain soil salinity equally across the area,” noted Tester. “The differences in plants grown in different plots were therefore mainly due to genetic composition rather than random environmental factors.” The researchers evaluated 10 traits related to crop performance, focusing in particular on the genetic architecture of flowering time, a key factor in generating a commercial high-performing crop. They searched for trait loci associated with specific genes in the plants that flourished in highly saline soils and identified a specific locus on chromosome 2H stemming from a father line

from northwest Iraq. Under saline conditions, the plants with this genetic mutation yielded 30 percent more than Barke. Tester’s team hopes to integrate the locus (alongside others linked to salt tolerance) into commercial lines and test the resulting plants in various geographical locations. Even if these new barley plants show higher tolerance only in certain places, this would be a significant step forward in tackling future food security. 1. Saade, S., Maurer, A., Shahid, M., Oakey, H., Schmöckel, S.M. et al. Yield-related salinity tolerance traits identified in a nested association mapping (NAM) population of wild barley. Scientific Reports 6, 32586 (2016).

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THE SIGNIFICANCE OF SEAWEED Carbon storage by coastal macroalgae is a significant but neglected aspect of the global carbon budget.

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he understanding of the global carbon cycle has been reshaped by KAUST researchers, who revealed a major role in this cycle for the abundance of seaweed growing around the world’s coasts. Several years ago, Professor Carlos Duarte, now director of the KAUST Red Sea Research Center, was among the first


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scientists to establish that marine vegetation plays a major role in the movement of carbon through the environment and all living organisms. The dominant players in the waters of coastal zones are macroalgae, more commonly known as seaweeds, such as kelp and sargassum. Now Duarte and Dorte Krause-Jensen from Aarhus University in Denmark have reviewed and quantified the role of macroalgae in trapping carbon. Their estimate is a highly significant 173 trillion grams of carbon sequestered in coastal seaweed globally per year1. “Marine macroalgae have largely been excluded from the discussion of marine carbon sinks,” said Duarte. He explained that this is due to neglecting the accumulation of macroalgae in deep-sea sediments. This latest review suggests that around 90 percent of global sequestration of carbon by macroalgae could be due to the transport of vegetation into the deep sea. The researchers propose two main mechanisms for this transport—seaweed drifting through undersea canyons, and deposition by sinking when the marine vegetation loses its natural buoyancy. “These processes in many vegetated coastal habitats sequester 10 times more carbon dioxide per hectare than a hectare of Amazonian forest,” said Duarte. This highlights the significance of seaweed when compared to a habitat often used as a carbon sink yardstick in discussions about climate change. “Understanding the major carbon

sinks in the biosphere is of paramount importance to identify where there are management opportunities to mitigate climate change,” Duarte noted. He explained that understanding where carbon goes provides opportunities for potential interventions that absorb more of the carbon dioxide that human activity releases into the atmosphere.

“Marine macroalgae have largely been excluded from the discussion of marine carbon sinks.” This latest analysis adds to other recent insights into carbon sequestration gained by Duarte and his colleagues, including a new understanding of the role of marine bacteria and of hydrocarbons deposited into the ocean from the atmosphere. Duarte now plans to use advanced techniques to identify and quantify the significance of macroalgal carbon deposition in existing sediments. One tool to use will be DNA analysis, which can reveal the species that contributed to the carbon in sediments. The global importance of climate change makes such work vital for planning effective management of the planet. 1. Krause-Jensen, D. & Duarte, C. M. Substantial role of macroalgae in marine carbon sequestration. Nature Geoscience 9, 737–742 (2016).

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Intertidal macroalgae on the coast of Greenland.


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Rising levels of CO2 in the oceans means fish have to adapt or die.

RHYTHM ADJUSTMENT FOR CO2 RISE Evolutionary alterations to circadian rhythm genes help reef fish adapt to the higher levels of carbon dioxide of future oceans. 20


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uch of the excess carbon dioxide (CO2) in our atmosphere released from burning fossil fuels is taken up by the oceans. However, the dissolved CO2 increases the acidity of the water, with inevitable impacts on fragile marine ecosystems such as coral reefs. Researchers at KAUST are conducting genomic experiments on generations of reef fish to determine how they might adapt to rapidly changing conditions1.

Fish rely on certain behaviors to avoid predation and to ensure their populations are replenished. Scientists have noticed that under higher CO2 conditions, young fish lose the ability to respond to cues from other fish, leaving them vulnerable to predation. Such behavioral changes are detrimental to the fish population; if they are to survive in altered environments, they need to be able to adapt. Tracking changes in the genome in subsequent generations provides insights into how such adaptations occur. Timothy Ravasi, KAUST professor of bioengineering, his postdoctoral fellow Celia Schunter and co-workers from the University’s Biological and Environmental Science and Engineering Division analyzed genetic data from parent and juvenile damselfish (Acanthochromis polyacanthus) to see how the fish reacted to ocean acidification. “We developed a unique fish rearing experiment that allowed us to measure the effects of ocean acidification across generations,” said Ravasi. “By combining data from the genome with information about RNA and protein expression, we were able to uncover the transgenerational molecular responses of the fish’s brains.” After rearing wild-type damselfish in captivity, the team separated adult fish into two groups: those that were naturally tolerant of high CO2 and those that were sensitive to it. Their offspring were

raised in the same CO2 conditions as their parents—either at current pH levels or at near-future levels with higher CO2. The immense amount of sequencing data generated by the project was unprecedented for a wild-type organism and took the team considerable time to analyze. The researchers found many molecular differences between the tolerant and sensitive offspring, including alterations to both genes and protein expression. Significantly, the main differences involved changes to the circadian rhythm genes in the tolerant offspring, a finding Ravasi had not anticipated. “In all coral reefs, CO2 levels naturally fluctuate between day and night due to coral symbiont photosynthesis,” explained Ravasi “Reef fish adjust their bodies to compensate for elevated nighttime CO 2, and of course this is controlled by circadian rhythm. It seems the tolerant offspring may have adjusted their circadian clocks as if it were always night!” Ravasi’s team was recently awarded a grant for expansion of their project to investigate the mechanisms behind these findings. 1. Schunter, C., Welch, M.J., Ryu, T., Zhang, H., Berumen, M.L. et al. Molecular signatures of transgenerational response to ocean acidification in a reef fish. Nature Climate Change Advance Online Publication (2016).

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GENOMICS: THE INTERSECTION OF FOLDING AND FUNCTION The dynamic three-dimensional organization of chromosomal structure can profoundly influence plant gene expression. 22


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he activity of genes can be profoundly affected by the three-dimensional arrangement of the chromosome within which they reside. These structural effects remain poorly understood, but assistant professor Moussa Benhamed of KAUST and colleagues have made important progress in exploring how chromosomes are organized in plant cells. The billions of bases of DNA within a given genome are generally maintained in a compacted form wound around histone proteins to form material called chromatin. However, chromatin is not merely a way to pack up chromosomal DNA, but it is also a highly dynamic system that routinely reorganizes as a means to control gene activity. “Numerous studies have shown the correlation between changes in the hierarchical organization of chromatin and specific gene expression patterns important for biological processes, such as response to environmental factors, cell identity and development,” said Benhamed. Microscopy studies demonstrated the dynamic nature of plant chromatin decades ago, but tools have only recently emerged that are able to map these rearrangements in detail. For example, a family of chromosome conformation capture techniques (also called 3C) use chemical agents that physically tether neighboring stretches of chromatin to one another. These strings of chromatin can then be purified and analyzed to identify likely interactions between DNA sequences situated either on separate regions of a single chromosome or even on entirely different chromosomes. This type of analysis can provide insights into chromatin rearrangements that bring genes in contact with remote regulatory sequences that control their activity or organize linear genes into loop

structures that facilitate rapid initiation of multiple rounds of expression. Current data already indicate that plant genomes lack certain organizational elements that are consistent features of virtually every animal genome, but Benhamed cautioned against overinterpretation of this finding. “It is still very early to talk about outright differences between cells from different phyla,” he said.

“Some studies have depicted the implications that certain mutations have for genome topology and how these could be related to disease.” In his view, the most exciting work in this field combines data from 3C or similar techniques with methods for monitoring other gene regulatory processes or even examining how changes in chromosome organization correlate with variations in genome sequence. “Some studies have depicted the implications that certain mutations have for genome topology and how these could be related to disease—in the case of humans—or certain other phenotypes,” Benhamed said. In the future, Benhamed noted he hopes to see the field move beyond standard model organisms in order for researchers to begin understanding how genome organization is shaped over time by evolution. “For us, this is one of the most important questions to be answered,” he said. Rodriguez-Granados, N.Y., Ramirez-Prado, J.S., Veluchamy, A., Latrasse, D., Raynaud, C. et al. Put your 3D glasses on: plant chromatin is on show. J. Exp. Bot. 67, 3205–21 (2016).

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Copolymers (top right) make up porous block copolymer membranes.

COPOLYMER MEMBRANES TOUGHENED UP Innovative chemistry has produced synthetic membranes with improved properties for industry, research and biomedicine.

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novel synthetic membrane produced by KAUST researchers is stronger and more stable than previous examples made by the same technique. The new material could fulfill the commercial potential that previous block copolymer membranes have shown. Porous synthetic membranes are used for filtration in research, industry and biotechnology. They are commonly made from polymers, which are materials constructed from repeating building blocks. Membranes made with block copolymers, which are comprised of two types of building blocks, have more uniform 24

pores than single polymer membranes, so they can filter particles more selectively. Despite their advantages, block copolymer membranes are still not used commercially because their main component tends to be polystyrene. Using this as a foundation makes the membranes easy to fabricate, but it is not strong enough for many applications. “Polystyrene is not considered to be a high-performance engineering material,” explained Professor Suzana Nunes from the KAUST Biological and Environmental Science and Engineering Division who led the research work. “It becomes soft at temperatures just above 100

degrees Celsius and is much less stable than polysulfone, another thermoplastic polymer.” Membranes made solely from polysulfones are currently the most commonly used in different applications, including seawater desalination, the food industry and artificial kidneys. Nunes and colleagues aimed to exploit the desirable properties of polysulfones—stability and the capacity to withstand high temperatures—to create stronger block copolymer membranes. “The main difference is that we used polysulfone blocks instead of polystyrene blocks,” noted Nunes. “However, there is no commercially available polysulfone block copolymer that is adequate for this application, so we had to synthesize it.” The chemical reaction required to create polysulfones differs from that required to produce the other polymer needed for the membrane, so Nunes and her team developed a technique for combining the two reactions. Once the polymers were synthesized, the researchers made membranes with a two-stage process called self-assembly and non-solvent induced phase separation, or SNIPS. The two polymers were initially mixed in solution to induce the formation of ordered structures called micelles. They were then placed in water, where they came together to form the final porous membrane. Stress tests showed that the new membranes were up to 67-fold stronger than polystyrene block copolymer membranes and could withstand higher temperatures, but they were also more ductile than membranes made from polysulfones alone. Nunes said that these properties make block copolymer membranes more suitable for commercial application, but she now wants to go further. “We are interested in membrane development to extend their properties for applications that are not covered by current polymeric membranes,” she said. Xie, Y., Moreno, N., Calo, V. M., Cheng, H., Hong, P.-Y. et al. Synthesis of highly porous poly(tertbutyl acrylate-b-polysulfone-b-poly(tert-butyl acrylate) asymmetric membranes. Polymer Chemistry 7, 3076–3089 (2016).

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2596 ENTREPRENEURIAL MINDS Over the past year, our Innovation and Economic Development team has hosted 2596 risk-takers, business leaders, creative thinkers and inventors. At KAUST, we help accelerate, incubate and commercialize big ideas. Entrepreneurs come away with more than just business knowledge - they gain a clear pathway for making their business concepts a reality, including opportunities to make connections with investors and strategic partners.

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TECHNOLOGY SEARCH FOR RELATIONSHIPS A sketch-based query for searching for relationships among objects in images could enhance the power and utility of image search tools.

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Wonka and his colleagues Paul Guerrero and Niloy Mitra from University College London wanted to add something more powerful to the currently limited repertoire of image search tools without adding extra metadata to existing images.

“Instead of describing just the individual objects occurring in an image, we wanted to describe the relationships between objects in a way that can be computed and searched for efficiently.” “Instead of describing just the individual objects occurring in an image, we wanted to describe the relationships between objects—such as ‘riding,’ ‘carrying,’ ‘holding’ or ‘standing on’—in a way that can be computed and searched for efficiently,” noted Wonka. The team came up with a query tool

they call a relation-augmented image descriptor (RAID) that takes either a written description or sketch of objects in a specific spatial relationship and searches for matches in the image database based on relatively simple geometric processing. “RAID allows us to search using a sentence such as ‘person standing on snowboard’ or to use a simple sketch of the desired composition of objects or an example image with the desired object composition,” said Wonka. “Our scheme uses a novel description based on the spatial distribution of simple relationships—like ‘above’ or ‘left of’—over the entire object, which allows us to successfully discriminate between different complex relationships.” RAID provides a new way to describe images and has potential applications in computer graphics, computer vision and automated object classification. The team is currently working on a threedimensional version of the descriptor that could help with computer interpretation of entire scenes. 1. Guerrero, P., Mitra, N.J., & Wonka, P. RAID: A relation-augmented image descriptor. ACM Transaction Graphics 35, 1-12 (2015). Reproduced with permission from ref 1© 2016 Association for Computing Machinery

earching for specific images may become easier thanks to a new tool that generates image queries based on a sketch or description of objects in spatial relationships1. The tool, which has been proposed by researchers from KAUST and University College London, makes it easier to search the world’s ever-expanding databases for pictures matching a wider and more powerful range of image queries. The enormous collections of photographs and pictures now available in online databases represent a remarkable resource for research and creative arts. As unfathomably rich as these databases might be, they are only as useful as a user’s capacity to use a query to search effectively. “When searching for images in a database like Flickr, the images need to include a short but informative description,” explained Peter Wonka, professor of Computer Science and leader of the study. “The description needs to be short to allow the search algorithm to match against millions of possibilities, but it also needs to be informative because the correct images need to be found based solely on this description.”

The relation-augmented image descriptor (RAID) allows searching of image databases based on the relationship between objects in a sketch or written query. 26


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Smart bandage technology provides instant updates on the condition of chronic wounds through a mobile phone app.

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njuries that fail to heal within three months, such as many diabetic foot ulcers, can require years of treatment and significant healthcare resources. A sensor-laden bandage developed by a research team at KAUST promises to reduce the burden on hospitals and enhance patient well-being by transforming how chronic wounds are monitored1. Researchers are working on new kinds of wearable sensors that alert users outside the hospital environment of potentially concerning changes in body temperature, heart rate or blood pressure. Chronic wound monitoring, however, has received less attention from device designers. One problem is that subtle forces that disrupt healing, such as bacterial infections, are difficult to detect with automated systems. Associate Professor Atif Shamim from the Electrical Engineering program at KAUST and his Ph.D. student

Muhammad Farooqui set out to design a smart bandage that monitors three parameters simultaneously—bleeding, pH levels and external pressure—to provide realtime updates on wound status using wireless technology. The team’s consultations with medical professionals revealed that variations in a wound’s pH level may indicate bacterial attacks. Combining this data with warnings about excess blood or pressure could alert users of the need for attention and help prevent ulcers from becoming chronic. Producing multicomponent sensors on stretchy bandage strips required a rethink about traditional microscale fabrication. Shamim and Farooqui used inkjet printing to directly pattern conductive carbon and silver ink onto plastic substrates. “Inkjet printing is a very suitable method to put electronics on delicate, flexible and unconventional mediums,” Shamim said. “It’s a low-cost manufacturing process, so

it helps to keep this technology affordable and disposable.” The researchers separated their prototype into two parts. They printed resistive and capacitive sensors onto a commercial bandage that could be discarded after use and then crafted wireless communication components, such as silver antenna patterns, onto a polymer film that easily sticks or detaches from the bandage. Making the wireless circuits reusable helps reduce the cost of the device even further, noted Shamim. On-body testing showed the bandage could communicate with a smartphonelike receiver up to 60 meters away, sending warnings such as “change bandage” when simulated blood conditions demanded it. Furthermore, the device was robust enough to be worn for an extended time and for its wearer to bend often. “With our smart bandage, long-term collection of medical data becomes reasonable and convenient,” said Shamim. “This could change how the healthcare industry operates, and we are working to translate it into a useful real-world product for chronic wound sufferers.” 1. Farooqui, M. F & Shamim, A. Low cost inkjet printed smart bandage for wireless monitoring of chronic wounds. Scientific Reports 6, 28949 (2016).

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Reproduced with permission from ref 1© 2016 Nature Publishing Group

A MODERN WAY TO HEAL OLD WOUNDS

The KAUST-developed sensor is printed on a disposable bandage strip using a low-cost inkjet printing technique. It has a detachable sticker that carries the wireless electronics and can be reused multiple times.


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GENTLE SENSORS FOR DIAGNOSING BRAIN DISORDERS

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lexible, low-cost sensor technology leading to safer and improved diagnoses and treatment of brain disorders has been developed by KAUST scientists1. Mapping the electrical activity of the brain is critical in understanding neurological disorders like depression and Alzheimer’s disease. Multielectrode arrays called Michigan or Utah arrays are currently used to monitor brain activity. Made from layers of conductive silicon needles, these rigid devices are inserted through the scalp to monitor the brain’s surface. The needles can cause inflammation of the tissues, so they must be removed within a year. Associate Professor Muhammad Hussain and Ph.D student Aftab Hussain from the Computer,

Electrical and Mathematical Science and Engineering Division wanted to develop a soft and flexible sensor that could be placed on the surface of the brain within the intracranial space, providing better contact and reducing the risk of damage to tissues. “Sensors require associated electronics to interface with us, and these electronics dissipate heat, thereby causing a burning effect in the brain that can permanently damage tissues,” explained M.Hussain. “The challenge is to keep the electronics away from the brain.” Working within these parameters, they fabricated a sensor made from gold electrodes encased in a polymer coating with the connections oriented vertically, and, by placing the connectors on top of the sensor and allowing them to pass through the polymer support, an integrated circuit (IC) could be attached to the flip side of the device, isolating it from the brain surface and preventing hotspots. The intracranial space of the brain presents an area of only 64 cm2 for mapping more than 80 billion neurons,

so not only is it safer to prevent the electronics from making contact with the brain, but it also maximizes the number of neurons that can be monitored by the sensor array. “The sensor is in contact with the soft tissues of the brain where it collects activity data, and the IC is placed on top, with a soft insulating polymeric material separating them, allowing a larger area to be mapped and a reduction in the heating effect,” M.Hussain noted. By using state-of-the-art technology used for fabricating integrated circuits, the researchers developed a method that could lead to mass-produced sensors that are safer, have improved mapping capabilities and are also robust enough for long-lasting functionality. “We are currently collaborating with Harvard-MIT Medical Institute on using the technique to improve the efficiency of the mapping interface system,” M.Hussain said. 1. Hussain, A.M. and Hussain, M.M. Deterministic integration of out-of-plane sensor arrays for flexible electronic applications. Small 12:37, 5141–5145 (2016)

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New sensor design paves the way for safer and more effective brain monitoring.


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ENHANCING UNDERSTANDING OF GENETIC REGULATION Researchers round up clues to track down enhancers.

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ur understanding of genetic regulation would be improved by better knowledge of regulatory elements known as enhancers, which are not located alongside the genes they control. In a recent paper published in Briefings in Bioinformatics, KAUST researchers reviewed the differences between various computational approaches to this problem and outlined some of the major challenges in the field1. Improving our understanding of genetic regulation will have major biotechnological and medical implications,

The review surveyed more than 30 computational tools and methods for identifying regulatory elements known as enhancers.

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Stephen Sweet / Alamy Stock Photo

“Without a gold standard, we cannot say which methods are better or worse.”

explained Professor Vladimir Bajic Director of the University’s Computational Bioscience Research Center. Bajic is also the senior author of the paper. The paper, which has been included in the International Society for Computational Biology’s list of recommended educational and training resources, surveyed more than 30 computational tools and methods for identifying enhancers. “Each of them is based on different assumptions, and they do not produce the same or very similar results,” said Bajic. “The fact that there are so many methods indicates that there isn’t a single one which is very good, because then the others would have been sidelined.”

The development and evaluation of these tools is hindered by the lack of a “gold standard” dataset against which to test them. Producing such a dataset is a significant experimental challenge, particularly since it would have to include the full diversity of enhancer types. Bajic is confident, however, that the rapid advance of experimental biology will resolve the problem in the next few years. While none of the tools is ideal, they have successfully identified enhancers, especially in studies with sufficient data to combine several approaches. In addition to making specific predictions, research with these tools has also generated broader insights about enhancers. For example, computational analysis revealed that the regions around predicted enhancers are enriched in binding sites for specific transcription factors.

The development of these tools can also help solve more general issues in machine learning, such as a problem known as class imbalance. If one of two classes is much more common, predictive classification algorithms can score well simply by consistently guessing the more common class, and thus often end up being “right” simply by chance. The approaches used to overcome this issue in identifying enhancers can also be applied in other domains facing the same challenge. “This is an unfinished story,” Bajic said. “Without a gold standard, we cannot say which methods are better or worse, but our review should help the community critically assess the approaches and then hopefully invent a better way to deal with this complex problem.” 1. Kleftogiannis, D., Kalnis, P. & Bajic, V. Progress and challenges in bioinformatics approaches for enhancer identification. Briefings in Bioinformatics, 1–13 (2015).

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MAKING SPACE FOR CLIMATE SIMULATIONS A statistics-based data compression scheme cuts data storage requirements for large-scale climate simulations by as much as 98 percent.

Climate science researchers are embarking on global-scale simulations at finer spatial resolutions, but these put a massive strain on data storage requirements. A data compression scheme reduces this by 98 percent. 32


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y accounting for the specific statistical structure of global climate simulation data, the University’s Professor Marc Genton partnered with a U.K. researcher to develop a novel and very effective data compression scheme for large-scale climate simulations1. The method promises to significantly reduce data storage requirements and accelerate the capacity for climate research. The ever-increasing power of supercomputers has allowed scientists to become more ambitious when it comes to simulations. In fields such as climate science, researchers are embarking on global-scale simulations at spatial resolutions that would have been unthinkable just a few years ago. Although this has expanded research possibilities, it has also put a huge strain on data storage requirements—a single large-scale simulation can produce many terabytes of data that must be stored and accessed for it to be useful. “The volume of data produced by these simulations is becoming so large that it is not possible to store it in computational facilities without incurring high costs,” explained Genton. “We see this not just

in climate science but also in astronomy, where new telescopes are capable of capturing large images at unprecedented resolution, and in engineering applications, where computer simulations are performed at very high-resolution in both space and time.”

“We essentially gave up on the idea of compressing information bit-by-bit and instead developed a method to compress the physics of the climate model itself.” With almost no prior research on compression methods for climate data, Genton, in collaboration with Stefano Castruccio from Newcastle University (U.K.), worked to formulate compression principles that would be effective for these types of simulations. Using previously unexplored statistical methods, the pair identified a compression framework that departs significantly from the approach of existing generic compression methods.

“The statistics of the output data provide flexible and useful parameters for compressing the very large data sets that arise in climate science,” said Castruccio. “We essentially gave up on the idea of compressing information bitby-bit and instead developed a method to compress the physics of the climate model itself.” The researchers considered a typical annual three-dimensional model of the global temperature field. By explicitly accounting for the space–time dependence and gridded geometry of the data, the compression scheme reduces the data to a set of estimated parameters that summarize the essential structure of the simulation results. Optimizing the compression scheme for each type of simulation can compress the data to as little as 2 percent of its original size. “The next step for us is to provide the climate community with easy-touse compression software that does not require technical knowledge in statistics,” Genton said. 1. Castruccio, S., Genton, M.G. Compressing an ensemble with statistical models: An algorithm for global 3D spatio-temporal temperature. Technometrics, 58, 319-328 (2016).

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EXPLORING ARTIFICIAL BIOSYNTHESIS Metabolic route explorer helps to optimize the pathways for artificial biosynthesis of valuable products.

The metabolic route explorer software could improve artificial biosynthesis.

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rtificial synthesis of natural products for medical and commercial use could be improved with new software developed by KAUST researchers. The system, called metabolic route explorer (MRE), is designed to optimize heterologous biosynthesis pathways by taking into account more information than existing software. In heterologous biosynthesis, organisms such as yeast and bacteria are genetically engineered to produce high quantities of specific products that are of medical or commercial value. “The production of antimalarial drugs in baker’s yeast and the production of spider silk in Escherichia coli are examples,” explained Associate Professor Xin Gao from the KAUST Computational Bioscience Research Center who led the new work. Software can be used to design the most appropriate synthetic pathways for heterologous biosynthesis, but existing

systems do not take into account the possibility of unwanted interactions between the host organism’s own metabolic machinery and the elements introduced by engineering. As a result, the pathways suggested by these systems may be suboptimal or, in some cases, impossible. Gao and colleagues developed MRE to address this problem. “For a given pair of starting and desired compounds in a given host organism, MRE ranks biosynthesis routes by predicting the effects of integrating new reactions into the endogenous metabolic system of the host,” Gao said. The researchers analyzed the performance of MRE in case studies of several high-value products that are already produced with heterologous biosynthesis. One case study was the production of naringenin, an antioxidant and antiviral against hepatitis C. MRE outperformed several other programs to rank the currently used biosynthesis pathway as the best. Furthermore, it was the only system to reveal a bottleneck in this pathway, presenting an opportunity for optimization. In another example, the pathway that MRE ranked to be the highest for production of artemisinic acid—a precursor to the antimalarial drug artemisinin—was slightly different and more energy-efficient than the currently used synthesis route. Not only does MRE outperform other software in identifying optimal pathways, but its design offers another advantage: many existing systems suggest pathways that involve enzymes or proteins that do not exist naturally but need to be synthesized, and MRE gets around this problem, too. “MRE was developed to suggest existing enzymes that can be used for heterologous pathways, so it takes a bottom-up approach in which the biosynthesis pathway is designed with well-characterized metabolic elements,” said Gao. “The system is expected to offer novel insights into the design and optimization of heterologous biosynthesis systems.” Kuwahara, H., Alazmi, M., Cui, X., Gao, X. MRE: a web tool to suggest foreign enzymes for the biosynthesis pathway design with competing endogenous reactions in mind. Nucleic Acids Research 44, W217-W225 (2016).

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UTILIZING A BROADER SHARE OF THE SOLAR SPECTRUM Graphene quantum dots can improve the efficiency of silicon solar cells.

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A graphene quantum dot (white) on top of a solar cell formed by silicon (Si) insulating (ITO) and metal (Au) layers.

are efficient in converting UV light to lower energies. The researchers integrated the quantum dots on a silicon solar cell device. The efficiency of the solar cells increased in comparison to control samples. For a mature technology to show a clear improvement in efficiency is promising because it can be produced using an easy manufacturing process. The test sample solar cells measured so far have not yet been optimized to be closer to the record-breaking performances seen in silicon. The researchers therefore plan to combine some other enhancement technologies previously

achieved in similar devices, He noted. “We have successfully utilized surface engineering treatments, including fabricating nanostructures and passivation layers, to improve the light harvesting and the electrical properties of solar cells. By integrating these techniques all together, we hope that in the next few years, the world record can be broken at KAUST,” he said. 1. Tsai, M.-L., Tu, W.-C., Tang, L., Wei, T.-C., Wei, W.-R., Lau, S.P., Chen, L.-J. & He, J.-H. Efficiency enhancement of silicon heterojunction solar cells via photon management using graphene quantum dot as downconverters. Nano Letters 16, 309-313 (2016).

Reproduced with permission from ref 1. © 2016 American Chemical Society

mall flakes of graphene could expand the usable spectral region of light in silicon solar cells to boost their efficiency, new research from KAUST shows 1 . Solar cell materials have become significantly cheaper to produce in recent years, yet further cost savings are needed to make solar technologies commercially attractive. The prevalence of silicon in solar cells makes them a good target for efficiency enhancement. “By improving the efficiency of silicon solar cells, we can provide a more cost-effective way for energy production,” said Jr-Hau He, KAUST Associate Professor of electrical engineering, who also led the research team. Graphene quantum dots are small flakes of graphene that are useful because of their interaction with light. One of these interactions is optical downconversion, which is a process that transforms light of high energies into lower energy (for example, from the ultraviolet (UV) to the visible). Downconversion can be used to boost solar cells. Silicon absorbs light very efficiently in the visible part of the spectrum and therefore appears black. However, the absorption strength of silicon for UV light is much smaller, meaning that less of this light is absorbed, reducing the efficiency of solar cells in that part of the spectrum. One way to circumvent this problem is the downconversion of UV light to energies where silicon is a more efficient absorber. Graphene quantum dots are ideal candidates for this purpose. They are easy to manufacture using readily available materials such as sugar and by then heating them with microwave radiation. While the dots are almost transparent to visible light, which is important to pass that light through to the solar cell, they


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KEEPING POLLUTION UNDER CONTROL 2016 KAUST

Sophisticated statistical methods can detect ozone pollution hotspots and monitor instrument failure.

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Postdoc Fouzi Postdoctoral fellow Fouzi Harrou discusses research work with Assistant Professor Ying Sun at KAUST.

zone is a troublesome pollutant at ground level and throughout the lower layer of the atmosphere. A statistical method developed by researchers at KAUST can detect abnormal ozone levels within large bodies of monitored data. “Our procedure could be used as an automatic tool,” said Assistant Professor Ying Sun from the University’s Computer, Electrical and Mathematical Science and Engineering Division. She noted that the method could act as an early warning system for dangerous pollution levels and potential technical problems. Ozone is the reactive form of oxygen that contains three atoms per molecule (O3) rather than the normal two. Groundlevel ozone is created by chemical reactions between other pollutants, especially oxides of nitrogen and carbon-based

compounds released in vehicle exhausts and by many industrial processes. The reactions that create ozone are promoted by bright sunlight, often leading to the serious air quality problem called photochemical smog. Exposure to the ozone can cause breathing difficulties, eye irritation and other health problems, and may also harm crops and other vegetation. Sun explained that the monitoring methods developed with colleague Fouzi Harrou can quickly and accurately detect ozone anomalies—localized spikes in ozone concentration indicated by sensor data. “This will allow us to warn the public of harmful ozone levels, but also to check the sensors in case a technical problem is the reason for an anomaly,” Sun said. The new scheme can monitor multiple stations simultaneously by integrating a statistical technique known as principal

component analysis into a traditional process control procedure. To test the method in the field, the KAUST researchers collaborated with a French team with access to data from a network of air quality monitoring systems in Normandy1. “The French air quality monitoring system is very well established,” said Sun. She explained that the French collaboration provided an ideal testing ground for the methods her team will next apply to Saudi Arabia and the Middle East. The results in France confirmed that the new procedure can offer improvements on existing methods, but further work is needed to reduce the level of errors that might spark false alarms. Sun and her colleagues also hope to apply their data analysis techniques to dust pollution, another major environmental issue in Saudi Arabia. J A N U A R Y 2 0 1 7 37


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STEP INTO THE WHITE LIGHT FOR FASTER COMMUNICATION

A nanocrystal-based material converts blue laser emission to white light for combined illumination and data communication.

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nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers 1. While Wi-Fi and Bluetooth are now well established technologies, there are several advantages gained by shortening the wavelength of the electromagnetic waves used for transmitting information. So-called visible-light communication (VLC) makes use of parts of the electromagnetic spectrum that are unregulated and is potentially more energy-efficient. VLC also offers a way to combine information transmission with illumination and display technologies—for example, 38

using ceiling lights to provide internet connections to laptops. Many such VLC applications require light-emitting diodes (LEDs) that produce white light. These are usually fabricated by combining a diode that emits blue light with phosphorous that turns some of this radiation into red and green light. However, this conversion process is not fast enough to match the speed at which the LED can be switched on and off. “VLC using white light generated in this way is limited to about one hundred million bits per second,” said KAUST Professor of Electrical Engineering Boon Ooi. Instead, Ooi, who is a member of the University’s Computer, Electrical and Mathematical Science and Engineering

Division, Associate Professor Osman Bakr from the Physical Science and Engineering Division and their colleagues used a nanocrystal-based converter that enables much higher data rates. The team created nanocrystals of cesium lead bromide that were roughly eight nanometers in size using a simple and cost-effective solution-based method that incorporated a conventional nitride phosphor. When illuminated by a blue laser light, the nanocrystals emitted green light while the nitride emitted red light. Together, these combined to create a warm white light. The researchers characterized the optical properties of their material using a technique known as femtosecond transient spectroscopy. They were able to show that the optical processes in cesium lead bromide nanocrystals occur on a time-scale of roughly seven nanoseconds. This meant they could modulate the optical emission at a frequency of 491 Megahertz, 40 times faster than is possible using phosphorus, and transmit data at a rate of two billion bits per second. “The rapid response is partly due to the size of the crystals,” said Bakr. “Spatial confinement makes it more likely that the electron will recombine with a hole and emit a photon.” Importantly, the white light generated using their perovskite nanostructures was of a quality comparable to present LED technology. “We believe that white light generated using semiconductor lasers will one day replace the LED white light bulbs for energy-efficient lighting,” said Ooi. 1. Dursun, I., Shen, C., Parida, M.R., Pan, J., Sarmah, S.P. et al. Perovskite nanocrystals as a color converter for visible light communication. ACS Photonics 3, 1150­–1156 (2016).

2106 KAUST

Nanocrystals that generate white light could help combine lighting and communications systems into one.


100 NATIONALITIES

More than just a university, KAUST is also a town that includes over 100 nationalities and almost 7,000 residents. The university's international community brings together people and their ideas from around the world to merge the best practices and ideas to create positive impact.

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SHARING MOVEMENT AIDS LEARNING Automated learning of an individual’s movement patterns shared over mobile and social networks could help us to connect better.

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nformation about our locations is recorded almost everywhere we go, either intentionally over social media networks like Facebook, or incidentally via our mobile phones and their cellular and Wi-Fi networks. Mining this location data is valuable for marketing and social networking, but to make effective use of the data for research, it is necessary to characterize the habitual movement patterns of individuals—something that computers have found difficult to do on their own. KAUST Assistant Professor Xiangliang Zhang, and PhD students Basma Alharbi and Abdulhakim Qahtan have now developed a computer scheme that can learn such mobility patterns and enhance the prediction of social ties and habitual activities without human intervention1. “Our latent mobility patterns reveal our way of life, work and habits,” explained Zhang. “This makes the raw data of an individual’s movement or trajectory a rich source of information that could be used to recommend social links based on shared common interests, habits or preferences.” There are many challenges to the automated learning of mobility patters from raw trajectory data. These include aspects such as missing data and locations, differences in the amount of data among individuals while trying to treat individuals equally and the lack of information on how socially important a particular location may be even if it is visited infrequently.

“The latent patterns manifested in such data are important for understanding human behavior in general and could potentially be used in other areas.” “We used a probabilistic approach to uncover the hidden patterns manifested in the observed raw movement data,” said Zhang. “Simply put, our model first describes how we think human movement data is generated, where the subject’s movements are governed by a small set of unobservable purposes that we infer and reverse engineer to reproduce the observed data.” For example, when a subject visits a movie theater, the event is mapped to the predefined purpose of “entertainment.” An individual’s movement habits can then be learned from the subject’s purposes. The team’s model also incorporates elements that allow it to handle situations of incomplete or disparate data. It does this by considering the time a location was visited, learning from groups of individuals to strengthen sparse data and introducing a mathematical transformation to handle variance in the popularity of different places. “Our work will be important in profiling and personalizing information services that could be used by recommendation systems and targeted advertising,” said Zhang. “However, the latent patterns manifested in such data are also important for understanding human behavior in general and could potentially be used in other areas, such as in fraud detection based on credit card usage patterns.” 1. Alharbi, B., Qahtan, A., Zhang, X. Minimizing user involvement for learning human mobility patterns from location traces. Association for the Advancement of Artificial Intelligence, 2016.

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KAUST has developed a computer scheme that can learn mobility patterns and enhance the prediction of social ties and habitual activities.


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HELPING COMPUTERS TO SEE WHO WE REALLY ARE Algorithms that train computers to automatically detect human activity in videos can improve online searches and real-world surveillance systems.

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2016 ActivityNet

ecent statistics from YouCaba approached the task with a visual recognition software. Video-anaTube reveal that users are system to recognize video context by lyzing algorithms rely heavily on datauploading incredible vol- looking for clues in camera motion and sets known as benchmarks that contain umes of content—nearly scene appearance. By segmenting pixel examples of human activities. These 1,000 days’ worth of videos are added data into foreground and background, benchmarks typically have a small numevery hour to the website. While these his system looked for distinct changes in ber of categories, and tend to overfocus numbers may bring joy to browsers of appearance or perspective—the upward on areas such as sports while underthe internet, they challenge companies movement of a camera following a pole representing the more regular events of such as Google who must process enor- vaulter, for instance—to train machine daily life. As part of their studies, Caba mous amounts of visual information learning software. and Escorcia are working to change this with minimal human intervention. These projects put Caba and Escor- with a hugely expanded benchmark KAUST researchers are now spear- cia in collaboration with Bernard Gha- known as ActivityNet. heading efforts to transform videos into The ActivityNet project uses crowdtools that teach computers fundamental “Finding ways for sourcing in combination with a rich skills about identifying people and their taxonomy system to classify hundreds software to match behavior. And two members of the Youof real-world human interactions. The Tube generation—Ph.D. students Fabian humans at analyzing researchers first searched the web for vidCaba and Victor Escorcia—are playing images is one of the eos depicting specific activities and then key roles in developing this technology, used Amazon’s “Mechanical Turk” web which may be applied in fields rang- holy grails of computer service—an on-demand, online workforce ing from online advertising to 24-hour vision research.” willing to perform small tasks for a fee— patient monitoring. to filter out unrelated “Given the large actions. Finally, the Mechanical Turk amount of video data workers annotate in the world, there is a need for algorithms the video timeframes with the ability to associated with the activity. automatically recognize and understand Escorcia noted that human activities,” ActivityNet is a large-scale video benchmark for understanding human activities. expansive databases said Caba. “Findlike ActivityNet proing ways for software to match humans nem, Assistant Professor of electrical vide a foundation for computer vision at analyzing images is one of the holy engineering at KAUST. Previous work researchers to tackle machine learning grails of computer vision research. It’s between Ghanem and Carlos Niebles problems such as mimicking neural netresulted in a 2014 Google Faculty works, which were previously considered what attracted me to this domain.” Both Caba and Escorcia are originally Award and inspired the undergradu- out of scope. “ActivityNet will help us from Colombia, where they attended the ate students to work with Ghanem. He in the same way roads and the electrical Universidad del Norte in Barranquilla as introduced them to the KAUST Visiting grid move the world,” he said. undergraduates. Under the direction of Student Research Program (VSRP)—an Caba and Escorcia also challenged Juan Carlos Niebles, the pair developed opportunity for talented students to researchers to utilize their large-scale innovative techniques for computerized work with a faculty mentor for up to benchmarking tool at the first annual video analysis. For example, Escorcia six months. They accepted the intern- ActivityNet competition, run as part of used a Microsoft Kinect sensor to cap- ship and soon realized that Ghanem’s the Conference on Computer Vision and ture the body movements of actors dem- expertise meshed perfectly with their Pattern Recognition in July 2016. This onstrating construction work and then career goals. meeting used a competitive leaderboard turned these poses into parameters for a “I was looking for an opportunity in system to motivate development of new machine learning algorithm. After being computer vision research and the VSRP video analysis algorithms with many trained with the image data, this soft- gave me a hand in a sense,” said Escor- possible applications. “These methods could aid contentware automatically distinguished differ- cia. “Having the opportunity to work ent construction activities in videos with with Professor Ghanem before starting based video retrieval and ad placement an 85 percent success rate. my Ph.D. program gave me a clearer idea for sites such as YouTube,” said Caba. about my research topic and the person “Moreover, these techniques can enable who would advise me.” automated detection and recognition Ph.D. students Fabian Caba (left) and Victor of abnormal or dangerous activities in After their visit to KAUST, both stuEscorcia (right) are working with KAUST dents applied for and were accepted into security-sensitive areas like airports or Assistant Professor Bernard Ghanem (center) to automate visual recognition technology. Ph.D. programs working on automating oil refineries.”

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GETTING A HANDLE ON EXTREMES A statistical model that accurately describes rainfall at both extremes opens the way for more reliable predictions of flood and drought risk.

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y tapping into the power of extreme value theory, an international team of researchers including Assistant Professor RaphaÍl Huser from the University’s Computer, Electrical and Mathematical Science and Engineering Division has developed a statistical model that overcomes the shortcomings of previous schemes to provide a reliable basis for climate research and the prediction of drought and flood. The model can accurately describe observed rainfall data and reliably predict the likelihood of future extreme events1. The analysis of hourly or daily rainfall data presents many challenges for researchers and hydrologists due to the distribution of the data. There are many values in the average range and

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only exceedingly rare data associated with extreme events like 1-in-100 year storms. A lack of tools to accurately describe and extrapolate extreme events from available observations severely limits hydrologists’ capacity to reliably predict the frequency of flood events and expected flood levels. “As extreme data are scarce by definition, it is very difficult to estimate extreme weather conditions and their frequency, especially beyond the maximum event in the observation period. Our model can be used, for example, to estimate the extent of a 100-year flood at a given location based on just 20 years of recorded data,” explained Huser. “The estimation of periods of extremely low rainfall is equally challenging using limited data.”

The analysis of rainfall extremes is usually performed by applying a different statistical model to that used for the average rainfall range. Both highand low-intensity rainfall events need to be treated separately in this way, since these rare events obey the rules of extreme value theory—an elegant mathematical framework dictating the occurrence of rare random events in time series data. This approach, however, results in physically unrealistic aberrations at the rainfall thresholds separating the ranges, and attempts to characterize long-term rainfall features using “sliced and diced” data sets that may no longer be representative of natural conditions. The approach taken by Huser’s team

uses the entire data set without thresholds by applying extreme value theory to both high-intensity and rare lowintensity rainfall events and smoothly linking the tails of the distributions together. “Our method, which has few parameters and is simple to use, avoids using complicated mixture models that are difficult to fit and apply in practice,” noted Huser. “Extreme events are handled properly by extreme value theory, without which the results could be biased in terms of estimating exceptionally high rainfall intensities.” 1. Naveau, P., Huser, R., Ribereau, P., Hannart, A. Modeling jointly low, moderate and heavy rainfall intensities without a threshold selection. Water Resources Research 52, 2753–2769 (2016).

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365 SUNSETS ON THE RED SEA

A destination for science and technology research and education, KAUST also offers a front row view of amazing sunsets on the Red Sea. Our residential community provides a distinctive work-live-play lifestyle and includes services from daycare and International Baccalaureate schools to recreational facilities and an on-site globally credentialed medical system.

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A GOLDEN REPLACEMENT Altering a single atom in a silver nanocluster considerably changes its properties, creating an exciting opportunity to design these clusters.

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he appearance of metals, such as their shiny surface or their electrical conductivity, is determined by the ensemble of atoms that comprise the metal. The situation differs on the molecular scale, and KAUST researchers have shown that replacing a single atom in a cluster of 25 silver atoms with one gold atom fundamentally changes its properties1. Metal atom nanoclusters are made from a core of a few metal atoms surrounded by a protective shell of stabilizing ligands. Nanoclusters come in different sizes, but each stable variation of nanoclusters has exactly the same number of metal atoms. This leads to very controllable properties, noted Osman Bakr, KAUST Associate Professor of material science and engineering and leader of the research team. “Nanoclusters have unique arrangements of atoms and size-dependent absorption, fluorescence, electronic and catalytic properties,” he said. A popular metal nanocluster is

[Ag25(SR)18]-, which consists of of 25 silver atoms. This nanocluster is unique as it corresponds to a gold nanocluster that has exactly the same number of atoms. Both clusters have different properties due to the different metal used. To understand how exactly the atomic composition affects these properties, the researchers replaced a single silver atom with gold. Replacing a single atom in a nanocluster is a difficult task. Direct chemical methods can be used, but these give little control over how many atoms are replaced, making it difficult to ascribe particular properties to the nanocluster structure. Instead, the researchers used a galvanic replacement process that relies on difference in the electrochemical potential between the incoming and outgoing atoms to induce atomic replacements. To their surprise, the process produced a reliable and precise atomic exchange in which only the center silver atom is replaced by gold. The replacement yielded dramatic

changes in the nanocluster. A solution of the silver nanoclusters appears orange, whereas after the replacement of the central atom the color turns dark green. This indicates more fundamental changes in properties, Bakr said. “The ambient stability and fluorescence of the nanocluster were enhanced by a factor of 25 as a result of this single atom replacement. Furthermore, we are now able to demonstrate the importance of a single atom impurity on nanoparticles and modulate the properties at the single atom level,” he noted. The reliable replacement of only a single gold atom opens the door to a more systematic investigation of metal nanoclusters, which can help to uncover the mechanisms of the chemical and physical changes arising from the replacement. 1. Bootharaju, M.S., Joshi, C.P., Parida, M.R., Mohammed, O.F. & Bakr, O.M. Templated atomprecise galvanic synthesis and structure elucidation of a [Ag24Au(SR)18]- nanocluster. Angewandte Chemie International Edition 55, 922 –926 (2016).

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Reproduced with permission from ref 1.© 2016 John Wiley and Sons.

Replacing metal atoms with gold ones can drastically change the properties of the material.


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From the transparent cockpit canopy of ďŹ ghter jets to everyday applications such as spectacle lenses and Blu-ray discs, polycarbonate plastics are valued for being light, strong and offering exceptional optical clarity. KAUST researchers have discovered a simple, clean, metal-free way to make polycarbonates from CO2.

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ne of the more environmentally friendly ways to make polycarbonates is to use carbon dioxide as one of the component monomers, making good use of what is otherwise an unwanted greenhouse gas. However, to make polycarbonates this way, manufacturers must currently use complex organometallic catalysts, which are difficult to make and which leave metal residues in the finished plastic. Not only can these metals be toxic, but they also discolor the polymer with a yellow taint that requires extra purification steps to remove. Instead of an organometallic catalyst, Professors Nikos Hadjichristidis and Yves Gnanou along with colleagues from the University’s Physical Science and Engineering Division developed a purely organic catalyst system that is highly effective, simple to use and requires no additional purification steps. To make polycarbonates from CO2, the gas is mixed with a partner monomer called an epoxide. “Common wisdom told us that to produce linear polycarbonate chains from the copolymerization of CO2 with epoxides, there is no option but to resort to organometallic complexes,” said Gnanou. The organometallic catalyst’s role is to capture epoxide molecules from the mixture and attach them to the growing polymer chain. Without the organometallic catalyst, the sluggish

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epoxide addition step meant the growing chains would often react with their own tail instead, forming cyclic structures rather than the desired long-chain polymer. “In polymerizations that are crippled by side reactions such as cyclizations, one classical way to foster the formation of linear chains is to activate the monomer,” Gnanou explained, which is what the researchers did. In place of the organometallic catalyst, the team used a pair of reaction initiators: an ammonium compound to capture and activate the CO2 and an electron-poor boron-based compound to activate the epoxide. This combination coupled the two monomers just as effectively as many organometallic catalysts. “The polycarbonates samples we obtained are not at all colored, and the activator used can be easily removed by washing the sample with water,” Gnanou said. The team believes that their approach could be used to make a wide range of polymers, Gnanou added. “The next step would be to apply the same concept to other epoxides and more generally to other related monomers,” he said. Zhang, D., Boopathi, S.K., Hadjichristidis, N., Gnanou, Y. & Feng, X. Metal-free alternating copolymerization of CO2 with epoxides: Fulfilling “green” synthesis and activity. Journal of the American Chemical Society 138, 11117 (2016).

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A composite structure consisting of a bulk zeolite encased in a mesoporous zeolite shell is shown here.

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CATALYSIS STEPS INTO THE THIRD DIMENSION Nonsurfactant polymers template produces a highly porous, threedimensional inorganic crystal to enhance catalysis and separation.

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igh-performance porous materials needed for the selective catalysis and the separation of large compounds have been developed by KAUST researchers 1. Zeolite is one such porous material that combines aluminum, silicon and oxygen into a crystalline network of molecular-sized cavities and channels. Its pores typically measure less than one nanometer because their synthesis uses small cations as templates. The tiny size and network configuration result in extensive surface areas as well as size and shape selectivity, which is a boon for catalysis and separation. On the other hand, this size also is limiting, as there is slow diffusion and low catalytic activity in cases where bulky molecules are involved. These size-related problems may be circumvented by hierarchical zeolites, which have micropores and larger pores wider than a few nanometers. While micropores provide catalytic activity and selectivity, the mesopores allow bulky molecules to rapidly diffuse through zeolites. To date, the production of hierarchical zeolites has relied on surfactants as templates. These molecules, which

simultaneously bear water-loving and water-repelling functional groups at their extremities, form layers alternating with zeolite sheets to give two-dimensional (2-D) structures. “From an application perspective, it’s better to have three-dimensional (3-D) structures than 2-D sheets,” said Associate Professor Yu Han from the KAUST Advanced Membranes & Porous Materials Center (AMPMC).

“From an application perspective, it’s better to have 3-D structures than 2-D sheets.” Han’s team has now developed a method that produces these 3-D hierarchical zeolites using nonsurfactant polymers as templates. The zeolites have highly crystalline structures with open and interconnected mesopores. In addition, the polymers also generate unique composites in which mesoporous zeolites are able to coat zeolite seeds. According to Han, sheets arise from strong intermolecular interactions between surfactant molecules. The team chose nonsurfactant polymers because

“we hypothesized that a 3-D structure would be produced if we minimized these interactions,” he said. The polymers play a dual role: they assist mesopore production while their many positively charged ammonium functional groups direct the zeolite crystallization. The researchers compared the catalytic performance of the hierarchical zeolites to that of bulk analogues for two reactions. When methanol was converted into aromatic hydrocarbons, in which the buildup of coke by-product deactivates catalysts, the zeolites outperformed their analogues. They maintained their activity longer and showed a higher conversion capacity and rate constant. Moreover, in the catalytic cracking of canola oil, which involves bulky reactants, they gave the highest conversion yields. “We are now exploring the full potential of these hierarchical zeolites for catalysis and separation applications with colleagues from the KAUST Catalysis Center and the University’s AMPMC,” Han said. 1. Tian, Q., Liu, Z., Zhu, Y., Dong, X., Saih, Y. et al. Beyond creation of mesoporosity: the advantages of polymer-based dual-function templates for fabricating hierarchical zeolites. Advanced Functional Materials 26, 1881–1891 (2016).

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60 MINUTES

Our marine scientists have immediate access to the Red Sea. The closest reefs can be reached in less than an hour and dozens more are within a 50 km range. The incredible biodiversity of the Red Sea holds untapped potential for discovery and serves as a model for understanding biological systems and their adaptation to climate change conditions.

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ELECTRIC FIELDS TAME THE FLAME A clearer understanding of how flame is affected by electric fields paves the way for advanced electrically assisted combustion technology.

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lame is a complex and dynamic phenomenon involving a constant flow of negatively and positively charged ions and electrons. For decades, researchers have attempted to exploit this charged property to control and stabilize flame, theoretically leading to lower emissions and more complete energy utilization. Applying an electric field that interacts with the charged particles is the most obvious means of achieving this type of flame control, but this approach has met with mixed success. Associate Professor Min Suk Cha and colleagues from the University’s Clean Combustion Research Center have now developed a model and validating experiment that teases out the scientific principles that underpin electrically assisted combustion for the first time1.

“Electrically assisted combustion has been held back partly because of a lack of scientific understanding of the many phenomenological observations and partly because of a lack of perfect applications,” noted Cha. “We are now able to choose the polarity of the electric field and the electrodes to achieve the desired flame control effect as a fundamental building block for studies and applications.” The response of flame to an electric field varies depending on the field’s direction, or its polarity. The electric field interacts with the flowing ions, changing their momentum, speed and direction, which in turn affects flame stability, flame front propagation and the generation of emission due to partial combustion. Cha and his team postulated that the nature of these

interactions between field and particle could be determined by the speed of the different particles. In particular, they thought that positive ions would respond much more slowly to the electric field than much lighter, negatively charged electrons. To test their new model, the research team had to come up with a way to measure these effects experimentally. Fortunately, the flame itself generates an electric current due to the flow of ions and electrons, and interactions with positive ions and electrons have different effects on the electric current, which can be measured with an experimental setup. The team also developed a counterflow diffusion flame setup that allowed them to control the location of the flame as well as form a quasi-onedimensional flame in the gap between the electrodes. “With this new scientific understanding of flame response, we are hopeful that novel electrically assisted combustion systems can be developed using scientific design rather than extensive trial and error,” Cha said. 1. Xiong,Y., Park, D.G., Lee,B.J., Chung, S.H., & Cha, M.S. DC field response of one-dimensional flames using an ionized layer model. Combustion and Flame 163, 317–325 (2016).

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The application of a strong electric field to a sheet of flame causes major changes that can be exploited to control combustion and emissions.


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The images show the vapor explosion of an 8 mm diameter drop of liquid Field’s metal as it falls into a pool of water.

FIERY EXPLOSIONS OF HOT METAL ON WATER Images from a high-speed camera reveal a microbead formation process during the vapor explosion of liquid metal dropping into a pool of water.

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he explosive reaction of a liquid metal dropping into water has been captured with high-speed cameras by researchers from KAUST. The images reveal how the explosive formation of water vapor around the liquid metal influences the shape of the metal as it hardens1. For certain metals, perfectly shaped microbeads are created during the powerful reaction with water. 54

Immersion of hot liquids in other liquids is not uncommon, even outside of the laboratory. An example is hot lava from a volcanic eruption encountering water reservoirs or flowing into the sea. This interaction can lead to dramatic reactions when a vapor layer forms around the liquid metal. The vapor layer can become unstable and quickly expands into hot clouds of water and ash, noted Siggi Thoroddsen, KAUST Professor of mechanical engineering,

who led the research team. “This happened when the Icelandic volcano Eyjafjallajökull erupted in 2010 and grounded airplanes all over Europe,” he said. The researchers studied related reactions in the lab using a metal alloy known as Field’s metal, which melts at low temperatures of around 60 degrees Celsius. With experiments conducted at 550 degrees Celsius metal temperature, the transfer of energy between the metal and the water is very violent. KAUST


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Ph.D. student Nadia Kouraytem wore a full protective facial mask and a fireresistant lab coat during these experiments. High-speed cameras captured the explosive process at speeds of up to 50,000 frames per second.

While initially only a small part of the metal interacted with the water, over a longer period increasingly more of the metal was exposed and took part in the reaction until the disintegration of the liquid metal into small beads. The images obtained were dramatic and showed an explosive reaction that tore the metal apart. In the case of Field’s metal, small spherical microbeads formed during the process. During the reaction, the metal transitioned through several stages with

increasing ferocity. While initially only a small part of the metal interacted with the water, over a longer period increasingly more of the metal was exposed and took part in the reaction until the disintegration of the liquid metal into small beads. The unusual microbead formation occurs due to the low melting temperature. Metals with a higher melting temperature (such as tin) solidify faster because their higher solidification temperature is reached more quickly upon cooling so that there is less time for the material to disintegrate. An example is the porous structures seen in solidified lava from volcanic eruptions. In the case of Field’s metal, the beads are highly uniform, and it will be interesting to study their creation processes further, noted Thoroddsen. “In future experiments, we want to better control the original drop, change its size and impact velocity. This should further probe the instabilities of the vapor layer that forms around the metal,” he said. 1. Kouraytem, N., Li, E. Q. & Thoroddsen, S.T. Formation of microbeads during vapor explosions of Field’s metal in water. Physical Review E 93, 063108 (2016).

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Super-resolution seismic imaging using resonant multiples significantly enhances the resolution of seismic images, providing a more accurate method for oil and gas exploration.

SEISMIC ECHO TURNS INTO SUPER-RESOLUTION IMAGES

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y analyzing echoes previously discarded as noise in seismic data, KAUST researchers have found a way to more than double the spatial resolution of subsurface seismic imaging1. The advance could improve the characterization of subsurface geology, with major implications for oil and gas exploration and seafloor research and engineering. Seismic imaging is a relatively quick way to estimate the structure and general properties of the ground at depth without drilling. The technique involves firing a pulse of vibration into the ground and then detecting the vibrations that return as the pulse bounces off boundaries between different types of rocks, liquids or voids. The time taken for the pulse to return is used to calculate the depth to each feature, resulting in a two-dimensional image of subsurface structure. Although this works remarkably well and is one of the critical exploration 56

techniques used to find new oil and gas deposits, the images tend to become less accurate and more fuzzy with depth and in complex geological areas. This can lead to missed deposits or false leads. In the past, geophysicists have used only the first return signal to detect the subsurface reflectors that correspond to geological boundaries. The seismic record also includes a lot of vibration noise that is filtered out. However, some of this noise is actually due to vibrations called resonant multiples that have bounced back and forth between reflectors before returning to the surface. “Think of a canyon and how when a word is shouted into it, it gets echoed back and forth between the two parallel walls,” explained Gerard Schuster, KAUST professor of Earth science and engineering and leader of the research team. “This type of sound wave is a resonant multiple and the principle in seismic imaging is the same: each time the wave echoes back and forth,

the round-trip time is multiplied to the point where we can measure much more precise distances, including subwavelength features on the canyon wall.” The resonant multiple scheme is able to more than double the imaging resolution compared with existing methods, and is the first practical seismic technique to realize super-resolution imaging capable of resolving features smaller than the signal wavelength. “This method will allow us to improve imaging of salt domes, which are often associated with gas deposits, and also detect subtle geologic changes in a layer that are indicative of hydrocarbon or mineral deposits,” Schuster said. “The technique also has potential applications in other fields, including in radar and medical acoustic devices.” 1. Guo, B., Huang, Y., Røstad, A., & Schuster, G. Far-field super-resolution imaging of resonant multiples. Science Advances 2, e1501439 (2016).

Reproduced from reference 1 under creative commons licence © 2016 KAUST

A signal processing technique that makes use of seismic echoes is able to image subsurface geology at unprecedented resolution.


2016 KAUST

Ultraviolet light can be used to stimulate two additional electronic states for data storage.

MEMORY DEVICE SEES THE LIGHT Ferroelectric tunnel junction promises low-power, high-density data storage.

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n electronic device that could lead to smaller, lowpower memory chips can now be controlled and probed by light, research from KAUST revealed. The device is a ferroelectric tunnel junction (FTJ) that contains a thin layer of a ferroelectric material sandwiched between two electrodes. Ferroelectric materials are intrinsically polarized so that negative electrical charge concentrates on one side of the layer and positive charge clusters on the opposite side. Applying an electric field flips this polarization, and the two states can represent the “1”s and “0”s of binary data. The device crucially does not need power to retain this data. Associate Professor Tom Wu from the Physical Science and Engineering Division and his colleagues created an FTJ

containing a film of ferroelectric samarium-doped bismuth iron oxide (SBFO) that was just three to nine nanometers thick1. One electrode was made of platinum and the other was niobium-doped strontium titanate (NSTO), a light-sensitive semiconductor. Electrons can sometimes tunnel through a very thin ferroelectric layer—a quantum mechanical process that allows them to skip across an energy barrier to create a current. In one of its polarization states, SBFO has a low tunneling electroresistance (TER) that allows electrons across. However, in the other polarization state, the team found that its TER is 100,000 times larger, which prevents electron tunneling. This is the largest change in TER ever seen for a FTJ, providing an unambiguous way to read its polarization state. Exposing the device to ultraviolet light

reduced this high TER tenfold, as light makes NSTO more conducting, which assists electron tunneling. “This means that we could acquire a total of four electronic states corresponding to polarization direction (left or right) and illumination condition (dark or light),” noted Wu. “Each electronic state can be used to store one bit of information. By introducing light illumination into FTJs, we double the data storage density, which could be very promising for future technology.” Although the TER difference between the two states gradually wanes, the team calculated that there would still be a significant distinction after 10 years, making it suitable for long-term data storage. It took about 10 microseconds to switch the device from one state to the other—faster than conventional flash memory but lower than some other forms of advanced memory. “One immediate goal of our research is to make these FTJ devices smaller and faster,” said Wu. “In addition, we will work to enhance the light detection capability of such ultrathin junctions.” 1. Hu, W. J., Wang, Z., Yu, W. & Wu, T. Optically controlled electroresistance and electrically controlled photovoltage in ferroelectric tunnel junctions. Nature Communications 7, 10808 (2016).

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SURFACE FRACTURES AS MAGMA MOVES Surface deformation caused by magma rising within the crust may in turn have prevented a volcanic eruption in Saudi Arabia.

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rare period of volcanic unrest in the rural Harrat Lunayyir region of Saudi Arabia in 2009 allowed KAUST researchers to piece together details of how activity within the crust can interact with the land surface. These insights may help inform predictions for regions under threat of potential volcanic activity, such as the Saudi city of Madinah. The movement of magma beneath the Earth’s surface increases the chances of earthquakes and volcanic activity and can trigger significant land surface deformation. Such activity largely occurs where continental plates are separating, which usually occurs deep under the sea where it is difficult to monitor the activity. As a result, scientists are unsure precisely how magmatic activity, faults and surface stresses interact. “The short but intense period of earthquake activity in Harrat Lunayyir led to the evacuation of 40,000 people,” explained Professor Sigurjón Jónsson from the University’s Physical Science and Engineering Division. Jónsson worked on the project with KAUST Ph.D. graduate Wenbin Xu and scientists from Italy. “After six weeks of increasing earthquakes the area went quiet—the magmatic activity had stalled and no eruption occurred, but we didn’t know why.” Jónsson’s team used interferometric synthetic aperture radar (InSAR) satellite images and found a few snapshots of the area taken during the six weeks. Although these were not all high-resolution

pictures, they were sufficient to begin to unravel what had happened. The images revealed fracturing and faulting on the land surface and the formation of a “graben”—a wedge-shaped piece of land that had subsided between two fault lines. Jónsson’s team also visited the site to observe the deformation first-hand. “By enhancing the InSAR data, we generated computer models to verify what happened beneath the surface,” Jónsson said. “Our results show that a dike a few meters thick—molten magma rising in a vertical sheet through cracks in the rocks—came within two kilometers of the surface in the first month. The dike then rapidly increased in volume over a few days and came within a kilometer of the surface. The associated stresses formed the graben.” The researchers replicated the scenario in a sandbox experiment and found an artificial dike created the same surface deformation patterns. Interestingly, the team believes that the stresses caused by the graben and faulting actually caused the dike to stall, preventing a volcanic eruption. This study provides a rare insight into subsurface and surface interactions during volcanic unrest and could inform predictions for other geologically-active areas. Xu, W., Jonsson, S., Corbi, F. & Rivalta, E. Graben formation and dike arrest during the 2009 Harrat Lunayyir dike intrusion in Saudi Arabia: Insights from InSAR, stress calculations and analog experiments. Journal of Geophysical Research: Solid Earth 121, 2837–2851 (2016).

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2016 Sabrina Metzger

KAUST researchers at the site of the volcanic unrest in Harrat Lunayyir, Saudi Arabia. The team believes that fracturing and subsidence on the surface caused by magmatic activity below actually prevented a volcanic eruption taking place in 2009.


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A CLEAN SEPARATION The efficient purification of propylene using a fine-tuned porous material delivers advances in petrochemical production.

of the pore system. A key factor in determining whether a molecule is adsorbed is the pore aperture size. Larger apertures are not efficient in differentiating adsorption of molecules. Therefore, it is important that the entrance to the pores is fine-tuned on the atomic scale to the dimensions of the target molecules. In previous work, the KAUST researchers developed a class of MOFs suitable for processes such as carbon dioxide capture, but these were unsuitable to separate propane from propylene, as these two molecules are very similar in shape and size.

“Unveiling this unique material and its distinctive separation properties was a real tour de force in metalorganic framework chemistry and materials design.” KAUST-7, a metalorganic framework (MOF) (blue) that adsorbs propylene (green) and rejects propane (red).

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breakthrough for the production of a key component for popular polymer materials has been achieved by researchers from KAUST. Professor Mohamed Eddaoudi and colleagues have developed a porous material that easily removes propane, a detrimental gas, from propylene, improving the potential for efficient fabrication of polypropylene polymers1. “Unveiling this unique material and its distinctive separation properties was a real tour de force in metal-organic framework (MOF) chemistry and materials design,” said Eddaoudi. Polypropylene-based polymers can be shaped into many forms and are widely 60

used in the multibillion dollar industry to produce plastic goods like food containers or furniture. The base compound, propylene, needs to be at least 99.5 percent pure, and present-day purification techniques based on a cryogenic distillation process are expensive and energy-intensive. The approach discovered by the KAUST researchers employs preferential adsorption, in which one compound is reversibly captured by a porous material and the other is rejected. Ideally suited for this task are MOFs, which are porous, three-dimensional structures in which inorganic building blocks are linked by organic molecules. The MOFs are large enough to capture a variety of gases depending on the size

The researchers have now replaced the silicon-based inorganic building blocks of that MOF with ones based on niobium, which are slightly larger. The overall crystal structure of the MOF remains the same, leading to a reduced pore aperture size of the new MOF. This compound, which is named KAUST-7, achieves an efficient separation between propane and propylene at room temperature and ambient pressures. The separation of the two molecules retains its efficiency for at least eleven repeated cycles and works robustly, noted Eddaoudi. “KAUST-7 is unique not only because it displays an impressive performance better than current benchmark materials, but also because it maintains distinctive separation properties in the presence of water as a result of its high chemical stability,” he added. 1. Cadiau, A., Adil, K., Bhatt, P.M., Belmabkhout, Y. & Eddaoudi, M. A metal-organic framework basedsplitter for separating propylene from propane. Science 353, 137-140 (2016).

2016 KAUST

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30% INCREASE

KAUST scientists have identified a strain of wild barley that demonstrates a 30% increase in crop yield under saline conditions. With the reality of freshwater scarcity, farmers will increasingly turn to using abundant seawater for irrigation. Discovering robust salt-tolerant crops is one step towards achieving global food security and sustainability.

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MODELING DUST FLOW FROM AFRICA TO ARABIA High-resolution modeling improves understanding of dust flow from Africa across the Red Sea toward the Arabian Peninsula.

2016 NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response

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iolent dust storms that carry dust over the Red Sea from Africa and toward Saudi Arabia can look spectacular from space. The dust brings nutrients into the Red Sea ecosystem and affects the solar energy balance and air quality across the region, with implications for health, climate, agriculture and industry. Researchers at KAUST have used a high-resolution computational model of summer dust storms that will help to decipher and predict the effects of these major atmospheric events1. One major mechanism generating the dust storms is known as haboob, and is associated with wind gusts produced by moist downdrafts from convection. “This convection is of small scale and usually is not resolved in the models,” explained KAUST Professor Georgiy Stenchikov, who heads a research group at the University that investigates the atmosphere and climate of the Red Sea and Arabian Peninsula. “Our model simulates the dynamics of haboobs from first principles.” 62

A key innovation of the new study is that it comprehensively encompasses all of the important processes. It examines in greater detail how dust is generated, transported through the atmosphere and then deposited in the sea or on land. The study also examines the radiative impact of the dust—the extent to which it alters the amount of energy from sunlight penetrating different layers of the atmosphere and down to the Earth’s surface.

“The results from our model compare well with ground-based and satellite observations.” The researchers applied the model to study a severe dust outbreak in June 2012, which allowed them to better understand and quantify these events more generally. Having real data to compare with the output generated through the model also offered a test of the reliability of the computer system.

“The results from our model compare well with ground-based and satellite observations,” said Stenchikov. He pointed out, however, that the model generally underestimates some effects of the dust on the penetration of solar energy through the atmosphere. Identifying such deficiencies would help refine the model and increase its usefulness. Stenchikov said that gaining a better understanding of the properties of the soil that generates the dust is a priority for future improvement. He emphasized there is still more to learn about the origins of the dust. This new work complements other studies by KAUST teams that are providing ever-better understanding of how dust and atmospheric conditions affect the sea and soil across the Arabian Peninsula and the impact of these on fisheries and agriculture. 1. Kalenderski, S. & Stenchikov, G. High-resolution regional modeling of summertime transport and impact of African dust over the Red Sea and Arabian Peninsula. Journal of Geophysical Research: Atmospheres 121, 6435-6458 (2016).


PH YSICAL SCIEN CE AN D EN GIN EERIN G DIVIS IO N Airborne dust over the Red Sea as imaged by NASA’s Aqua satellite in June 2016.

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SEE-THROUGH CIRCUITRY 2016 KAUST

Atom-by-atom deposition leads to low-cost, highperformance transparent electronic materials.

By layering one layer of atoms at a time, KAUST researchers are producing high performance transparent circuits.

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igh-performance electronic circuits made entirely from transparent materials could have countless applications ranging from head-up displays on car windscreens to transparent TV sets and smart windows in homes and offices. Researchers at KAUST have found a way to make transparent transistors and other essential components of electronic circuitry using inexpensive and readily available materials and a simple fabrication technique1. Indium tin oxide (ITO) is the current material of choice for electronics because it combines optical transparency with electrical conductivity. Its uses range from touch-sensitive smartphone screens to light-harvesting solar panels. Indium is in short supply, however, and as demand increases for ITO-containing devices, so does the price of indium. One promising low-cost ITO alternative is a transparent material known as aluminum-doped zinc oxide (AZO). “The elements that make up this material are more abundant than indium, 64

making AZO a commercially sensible option,” said Professor Husam Alshareef from the KAUST Physical Science and Engineering Division, who also led the research. “However, electronic devices made using AZO have traditionally shown inferior performance to devices made using ITO.” To overcome this limitation, Alshareef and his research team used a high-precision technology called atomic layer deposition, a process in which the circuitry is built up a single layer of atoms at a time. Volatile vapors of aluminum and zinc in the form of trimethyl aluminum and diethyl zinc were alternately introduced onto the transparent substrate, where they adhere to the surface in a single layer before reacting in situ to form AZO. “Using atomic layer deposition to grow all active layers simplifies the circuit fabrication process and significantly improves circuit performance by controlling layer growth at the atomic scale,” Alshareef explained. For many electronic devices, the key

component is the thin film transistor. When combined in great numbers, these devices allow computers to do calculations, drive displays and act as active sensors. Alshareef used a transparent material called hafnium oxide that was sandwiched between layers of zinc oxide to form the highly-stable transistors used to fabricate the transparent circuits. “Our transistor properties are the best reported so far for fully transparent transistors using AZO contacts,” said Ph.D. student Zhenwei Wang, who carried out much of the experimental work. Another advantage of Alshareef’s approach is that atomic layer deposition only requires a temperature of 160 degrees Celsius to form each layer, which is low enough for the transparent circuitry to be formed on flexible plastic substrates as well as on rigid glass. 1. Nayak, P.K., Wang, Z. & Alshareef, H.N. Indiumfree fully transparent electronics deposited entirely by atomic layer deposition. Advanced Materials 28:35, 7736–7744 (2016).


60%

MORE FRESHWATER Using the same amount of electricity, our full-scale in-house research pilot plant has generated a 60 percent increase of freshwater production. This solar-powered method integrates adsorption and thermal desalination processes for an energy-efficient and sustainable solution. As the global reliance on desalination increases, these types of technologies are a significant contribution towards a water-secure world.

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6000 TIMES FASTER

While it could take 210 days using a conventional nuclear magnetic resonance (NMR) spectrometer to obtain a silicon NMR spectrum, it takes only 51 minutes to acquire this on our dynamic nuclear polarization NMR. The KAUST Imaging and Characterization Core Lab hosts the most advanced NMR to date, allowing our researchers to perform experiments on highly dilute and challenging samples in extremely efficient timeframes.

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KAUST Discovery - Issue 3  

From curiosity to innovation

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