National Research Foundation of Korea

Yongsan Gu, South Korea

National Research Foundation of Korea

Yongsan Gu, South Korea
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News Article | May 4, 2017
Site: www.eurekalert.org

A recent study, affiliated with UNIST has engineered a self-sustaining sensor platform to continuously monitor the surrounding environment without having an external power source. This research has been led by the team of Professor Jaehyouk Choi of Electrical and Computer Engineering at UNIST in collaboration with Professor Wonjoon Choi of Mechanical Engineering at Korea University. The findings, published in the March issue of the prestigious journal, Nano Energy note that the proposed platform is expected to contribute to advanced sensing functions of a self-sustaining system for various targeted-ambient elements. In the study the research team presented a self-sustaining water-motion-sensing (SS-WMS) platform to monitor and display the time-varying dynamics of water-motion, such as frequency and amplitude, using only the energy harvested from the water-motion itself. A self-sustaining sensor platform is a core component for Internet-of-Things (IoTs) and smart-grid systems. The existing sensor platforms require energy to operate and display the detected information. Therefore, monitoring, processing, and displaying the minute changes of a targeted-environmental element in a real-time fashion without the use of external power sources or energy storages, like batteries has been challenging. The research team solved this problem with the use of energy harvesting, an essential technology for permanent sensor platforms. Energy harvesting, also known as energy scavenging, is a technology for the harvesting of energy from various sources in the ambient environment, such as wind, water, light, heat, and mechanical energy for conversion into convebient use electric energy. "It is virtually impossible to manually power a large number of sensors or periodically replace the batteries," says Professor Choi at UNIST. "The newly-developed semiconductor circuit is capable of performing multiple functions simultaneously, which include energy harvesting and analysis of dynamics." The proposed sensor platform consists of a water-contact-based triboelectric nanogenerator (WC-TENG), a self-sustaining water-motion sensor integrated circuit (SS-WMS IC) on a test printed circuit board (PCB), and an LED array for displaying the detected frequencies and amplitudes of water motion. The circuits that store the harvested electrical energy and simultaneously analyze the signals are made using CMOS (Complementary Metal-Oxide Semiconductor) process. CMOS is an economically feasible method used in the production of semiconductors, as well as analog and digital circuits. It is composed of P-type and N-type transistors and can be designed as circuits that process various signals. Moreover, due to the low cost of manufacturing, it is also advantageous for commercialization. In this study, Professor Choi's team designed the SS-WMS IC based on standard 65-nm CMOS technology, so that one CMOS semiconductor chip about the size of a grand of sand to perform multiple functions simultaneously. According to the research team, their newly-developed SS-WMS platform has overcome the intrinsic limitations of prior self-sustaining sensors by improving the reliability and the continuity of real-time operation and delivering more useful and sophisticated information of the targeted ambient elements. It is also capable of conducting energy generation and harvesting, capacitor charging, water motion analysis, as well as LED control for displaying sensed information without hampering the mobility of sensors or demanding significant efforts and costs for follow-up management, respectively Moreover, because the integrated one-platform concept requires no external power source and significanly reduces energy storage requirements, it can be applied to wireless or no-power sensor platform and grid-scale renewable energy plants, the research team notes. Professor Choi notes, "This newly-developed sensor platform is a low-power device that is operated solely by the energy harvested from the water-motion itself." He adds, "It can be used as an environmental sensor platform for continuous monitoring of the flows of water or currents, the total amount of rainfall per hour, as well as a leak or accidental spill of hazardous waste at industrial sites." "The entire platform operation can be powered solely by the harvested energy from the WC-TENG," says Professor Choi. "We expect this platform can contribute to the development of new types of self-sustaining sensing platforms for liquids, such as seawater and wave dynamics, rainfall tracking, and permanent liquid-leakage monitoring systems." This work has been supported by the Basic Science Research Programs through the National Research Foundation of Korea (NRF), funded by the Ministry of Education and the Ministry of Science, ICT & Future Planning. Dongjoon Shin,Taeho Seong, Jaehyouk Choi, and Wonjoon Choia, "Self-sustaining water-motion sensor platform for continuous monitoring of frequency and amplitude dynamics," Nano Energy, (2017).


News Article | April 17, 2017
Site: www.eurekalert.org

An eco-friendly method to synthesize DNA-copper nanoflowers with high load efficiencies, low cytotoxicity, and strong resistance against nucleases has been developed by Professor Hyun Gyu Park in the Department of Chemical and Biomolecular Engineering and his collaborators. The research team successfully formed a flower-shaped nanostructure in an eco-friendly condition by using interactions between copper ions and DNA containing amide and amine groups. The resulting nanoflowers exhibit high DNA loading capacities in addition to low cytotoxicity. Flower-shaped nanocrystals called nanoflowers have gained attention for their distinct features of high surface roughness and high surface area to volume ratios. The nanoflowers have been used in many areas including catalysis, electronics, and analytical chemistry. Of late, research breakthroughs were made in the generation of hybrid inorganic-organic nanoflowers containing various enzymes as organic components. The hybridization with inorganic materials greatly enhanced enzymatic activity, stability, and durability compared to the corresponding free enzymes. Generally, the formation of protein nanocrystals requires high heat treatment so it has limitations for achieving the high loading capacities of intact DNA. The research team addressed the issue, focusing on the fact that nucleic acids with well-defined structures and selective recognition properties also contain amide and amine groups in their nucleobases. They proved that flower-like structures could be formed by using nucleic acids as a synthetic template, which paved the way to synthesize the hybrid nanoflowers containing DNA as an organic component in an eco-friendly condition. The team also confirmed that this synthetic method can be universally applied to any DNA sequences containing amide and amine groups. They said their approach is quite unique considering that the majority of previous works focused on the utilization of DNA as a linker to assemble the nanomaterials. They said the method has several advantageous features. First, the 'green' synthetic procedure doesn't involve any toxic chemicals, and shows low cytotoxicity and strong resistance against nucleases. Second, the obtained nanoflowers exhibit exceptionally high DNA loading capacities. Above all, such superior features of hybrid nanoflowers enabled the sensitive detection of various molecules including phenol, hydrogen peroxide, and glucose. DNA-copper nanoflowers showed even higher peroxidase activity than those of protein-copper nanoflowers, which may be due to the larger surface area of the flower- shaped structures, creating a greater chance for applying them in the field of sensing of detection of hydrogen peroxide. The research team expects that their research will create diverse applications in many areas including biosensors and will be further applied into therapeutic applications. Professor Park said, "The inorganic component in the hybrid nanoflowers not only exhibits low cytotoxicity, but also protects the encapsulated DNA from being cleaved by endonuclease enzymes. Using this feature, the nanostructure will be applied into developing gene therapeutic carriers." This research was co-led by Professor Moon Il Kim at Gachon University and KAIST graduate Ki Soo Park, currently a professor at Konkuk University, is the first author. The research was featured as the front cover article of the Journal of Materials Chemistry B on March 28, Issue 12, published by the Royal Society of Chemistry. The research was funded by the Mid-Career Researcher Support Program of the National Research Foundation of Korea and the Global Frontier Project of the Ministry of Science, ICT & Future Planning.


News Article | April 17, 2017
Site: www.cemag.us

An eco-friendly method to synthesize DNA-copper nanoflowers with high load efficiencies, low cytotoxicity, and strong resistance against nucleases has been developed by Professor Hyun Gyu Park and his collaborators in the Korea Advanced Institute of Science and Technology’s (KAIST) Department of Chemical and Biomolecular Engineering. The research team successfully formed a flower-shaped nanostructure in an eco-friendly condition by using interactions between copper ions and DNA containing amide and amine groups. The resulting nanoflowers exhibit high DNA loading capacities in addition to low cytotoxicity. Flower-shaped nanocrystals called nanoflowers have gained attention for their distinct features of high surface roughness and high surface area to volume ratios. The nanoflowers have been used in many areas including catalysis, electronics, and analytical chemistry. Of late, research breakthroughs were made in the generation of hybrid inorganic-organic nanoflowers containing various enzymes as organic components. The hybridization with inorganic materials greatly enhanced enzymatic activity, stability, and durability compared to the corresponding free enzymes. Generally, the formation of protein nanocrystals requires high heat treatment so it has limitations for achieving the high loading capacities of intact DNA. The research team addressed the issue, focusing on the fact that nucleic acids with well-defined structures and selective recognition properties also contain amide and amine groups in their nucleobases. They proved that flower-like structures could be formed by using nucleic acids as a synthetic template, which paved the way to synthesize the hybrid nanoflowers containing DNA as an organic component in an eco-friendly condition. The team also confirmed that this synthetic method can be universally applied to any DNA sequences containing amide and amine groups. They said their approach is quite unique considering that the majority of previous works focused on the utilization of DNA as a linker to assemble the nanomaterials. They said the method has several advantageous features. First, the “green” synthetic procedure doesn’t involve any toxic chemicals, and shows low cytotoxicity and strong resistance against nucleases. Second, the obtained nanoflowers exhibit exceptionally high DNA loading capacities. Above all, such superior features of hybrid nanoflowers enabled the sensitive detection of various molecules including phenol, hydrogen peroxide, and glucose. DNA-copper nanoflowers showed even higher peroxidase activity than those of protein-copper nanoflowers, which may be due to the larger surface area of the flower- shaped structures, creating a greater chance for applying them in the field of sensing of detection of hydrogen peroxide. The research team expects that their research will create diverse applications in many areas including biosensors and will be further applied into therapeutic applications. Park says, “The inorganic component in the hybrid nanoflowers not only exhibits low cytotoxicity, but also protects the encapsulated DNA from being cleaved by endonuclease enzymes. Using this feature, the nanostructure will be applied into developing gene therapeutic carriers.” This research was co-led by Professor Moon Il Kim at Gachon University and KAIST graduate Ki Soo Park, currently a professor at Konkuk University, is the first author. The research was featured as the front cover article of the Journal of Materials Chemistry B on March 28, Issue 12, published by the Royal Society of Chemistry. The research was funded by the Mid-Career Researcher Support Program of the National Research Foundation of Korea and the Global Frontier Project of the Ministry of Science, ICT & Future Planning.


News Article | May 8, 2017
Site: www.cemag.us

The concept of a perfect lens that can produce immaculate and flawless images has been the Holy Grail of lens makers for centuries. In 1873, a German physicist and optical scientist by the name of Ernst Abbe discovered the diffraction limit of the microscope. In other words, he discovered that conventional lenses are fundamentally incapable of capturing all the details of any given image. Since then, there have been numerous advances in the field to produce images that appear to have higher resolution than allowed by diffraction-limited optics. In 2000, Professor Sir John B. Pendry of Imperial College London — the John Pendry who enticed millions of Harry Potter fans around the world with the possibility of a real Invisibility Cloak — suggested a method of creating a lens with a theoretically perfect focus. The resolution of any optical imaging system has a maximum limit due to diffraction but Pendry’s theoretic perfect lens would be crafted from metamaterials (materials engineered to have properties not found in nature) to go beyond the diffraction limit of conventional lenses. Overcoming this resolution limit of conventional optics could propel optical imaging science and technology into realms once only dreamt by common Muggles. Scientists all over the world have since endeavored to achieve super-resolution imaging that capture the finest of details contained in evanescent waves that would otherwise be lost with conventional lenses. Hyperlenses are super-resolution devices that transform scattered evanescent waves into propagating waves to project the image into the far-field. Recent experiments that focus on a single hyperlens made from an anisotropic metamaterial with a hyperbolic dispersion have demonstrated far-field sub-diffraction imaging in real time. However, such devices are limited by an extremely small observation area which consequently require precise positioning of the subject. A hyperlens array has been considered to be a solution, but fabrication of such an array would be extremely difficult and prohibitively expensive with existing nanofabrication technologies. Research conducted by Professor Junsuk Rho’s team from the Department of Mechanical Engineering and the Department of Chemical Engineering at Pohang University of Science and Technology in collaboration with research team from Korea University has made great contributions to overcoming this obstacle by demonstrating a scalable and reliable fabrication process of a large scale hyperlens device based on direct pattern transfer techniques. This achievement has been published in the world-renowned Scientific Reports. The team solved the main limitations of previous fabrication methods of hyperlens devices through nanoimprint lithography. Based on a simple pattern transfer process, the team was able to readily fabricate a perfect large-scale hyperlens device on a replicated hexagonal array of hemisphere substrate directly printed and pattern-transferred from the master mold, followed by metal-dielectric multilayer deposition by electron beam evaporation. This 5 cm x 5 cm hyperlens array has been demonstrated to resolve sub-diffraction features down to 160 nm under a 410 nm wavelength visible light. Rho anticipates that the research team’s new cost-effective fabrication method can be used to proliferate practical far-field and real-time super-resolution imaging devices that can be widely used in optics, biology, medical science, nanotechnology, and other related interdisciplinary fields. This research was supported by the National Research Foundation of Korea (NRF) grants of Young Investigator program, Engineering Research Center program, Global Frontier program, Pioneer Research program, and the Commercialization Promotion Agency for R&D Outcomes (COMPA) grant, all funded by the Ministry of Science, ICT and Future Planning (MSIP) of the Korean government.


News Article | April 21, 2017
Site: www.eurekalert.org

The concept of a perfect lens that can produce immaculate and flawless images has been the Holy Grail of lens makers for centuries. In 1873, a German physicist and optical scientist by the name of Ernst Abbe discovered the diffraction limit of the microscope. In other words, he discovered that conventional lenses are fundamentally incapable of capturing all the details of any given image. Since then, there have been numerous advances in the field to produce images that appear to have higher resolution than allowed by diffraction-limited optics. In 2000, Professor Sir John B. Pendry of Imperial College London -- the John Pendry who enticed millions of Harry Potter fans around the world with the possibility of a real Invisibility Cloak -- suggested a method of creating a lens with a theoretically perfect focus. The resolution of any optical imaging system has a maximum limit due to diffraction but Pendry's theoretic perfect lens would be crafted from metamaterials (materials engineered to have properties not found in nature) to go beyond the diffraction limit of conventional lenses. Overcoming this resolution limit of conventional optics could propel optical imaging science and technology into realms once only dreamt by common Muggles. Scientists all over the world have since endeavored to achieve super-resolution imaging that capture the finest of details contained in evanescent waves that would otherwise be lost with conventional lenses. Hyperlenses are super-resolution devices that transform scattered evanescent waves into propagating waves to project the image into the far-field. Recent experiments that focus on a single hyperlens made from an anisotropic metamaterial with a hyperbolic dispersion have demonstrated far-field sub-diffraction imaging in real time. However, such devices are limited by an extremely small observation area which consequently require precise positioning of the subject. A hyperlens array has been considered to be a solution, but fabrication of such an array would be extremely difficult and prohibitively expensive with existing nanofabrication technologies. Research conducted by Professor Junsuk Rho's team from the Department of Mechanical Engineering and the Department of Chemical Engineering at Pohang University of Science and Technology in collaboration with research team from Korea University has made great contributions to overcoming this obstacle by demonstrating a scalable and reliable fabrication process of a large scale hyperlens device based on direct pattern transfer techniques. This achievement has been published in the world-renowned Scientific Reports. The team solved the main limitations of previous fabrication methods of hyperlens devices through nanoimprint lithography. Based on a simple pattern transfer process, the team was able to readily fabricate a perfect large-scale hyperlens device on a replicated hexagonal array of hemisphere substrate directly printed and pattern-transferred from the master mold, followed by metal-dielectric multilayer deposition by electron beam evaporation. This 5 cm x 5 cm hyperlens array has been demonstrated to resolve sub-diffraction features down to 160 nm under a 410 nm wavelength visible light. Professor Rho anticipates that the research team's new cost-effective fabrication method can be used to proliferate practical far-field and real-time super-resolution imaging devices that can be widely used in optics, biology, medical science, nanotechnology, and other related interdisciplinary fields. This research was supported by the National Research Foundation of Korea (NRF) grants of Young Investigator program, Engineering Research Center program, Global Frontier program, Pioneer Research program, and the Commercialization Promotion Agency for R&D Outcomes (COMPA) grant, all funded by the Ministry of Science, ICT and Future Planning (MSIP) of the Korean government.


News Article | May 23, 2017
Site: www.eurekalert.org

DURHAM, N.C. -- Once hailed as a breakthrough in cancer treatment, immunotherapies are now raising concerns as doctors note new side effects like severe allergic reactions, acute-onset diabetes and heart damage. These drugs, which work by unleashing the immune system to fight cancer, are only effective in about a fifth of cases, prompting many patients to wonder if they are worth the risk. But a new study from Duke University researchers suggests there may be a quick and easy way to predict which cancer patients are likely to benefit from immunotherapy treatments. The researchers showed that a molecule called PD-L1, which is blocked by the popular immunotherapy drug nivolumab, acts not only on immune cells but also on the nerve cells that signal pain. That insight could lead to a simple test that measures subtle differences in pain sensitivity to gauge whether or not the body is responding to treatment. The findings, published May 22 in Nature Neuroscience, underscore the surreptitious nature of cancer, which uses a variety of tricks to evade detection by the body's natural defense mechanisms. "Cancer cells are smart. We already knew that they produced PD-L1 to suppress the immune system," said senior study author Ru-Rong Ji, Ph.D., professor of anesthesiology and neurobiology at Duke University School of Medicine. "But there's another defense system at play as well, and that is pain. We showed that this well-known molecule can mask pain, so that cancers can grow without setting off any alarms before metastasis." In its early stages, when cancer cells are just starting to grow and multiply in a given tissue or organ, the disease is not usually painful. But as the cancer becomes more aggressive and spreads throughout the body, these cells secrete thousands of pain-inducing chemicals, which either trigger pain-sensing nerve fibers or, in the case of molecules like nerve growth factor, generate entirely new ones. The pain can become so unbearable that some cancer patients die from opioid overdoses. Ji has been studying pain for over twenty years. Recently, his group noticed that mouse models of melanoma didn't show the typical signs of pain that he observed in mice with other kinds of cancer, which would flinch or lick their hind paws whenever they were in discomfort. Ji also knew that melanoma cells could produce a molecule called PD-L1, which latched onto a receptor called PD-1 on the surface of white blood cells, effectively putting the brakes on the immune response. Ji wondered whether there was a connection. So his team treated mice with nivolumab, a drug that prevents PD-L1 from binding to PD-1. Then they poked the animals' hind paws with a calibrated filament and measured how much force it took for them to withdraw their hind paws. They found that the mice responded to much lower forces than before treatment, indicating they had become more sensitive to pain. In addition, they also found that nivolumab caused spontaneous pain in mice with melanoma, which made them tend to their affected hindpaws like never before. Next, the researchers performed the opposite experiment. They injected PD-L1 -- the pain-masking factor in this equation -- into the hind paws or spinal cord of mouse models of three different kinds of pain -- inflammatory, neuropathic and bone cancer pain. In every case, the injections of PD-L1 had an analgesic effect, deadening the mice's sensitivity to pain. "The effect was surprisingly fast," said Ji. "We saw a reduction of pain in under half an hour." To figure out the mechanism behind this quick response, Ji's team examined the sensory neurons of the dorsal root ganglion (DRG), a collection of nerves and neurons near the top of the spinal cord. They isolated these cells from mouse DRGs as well as human DRGs from donors and cultured them in a dish, with or without PD-L1, and then recorded their electrical activity. The researchers found that PD-L1 impaired the ability of sodium channels to fire neurons (action potentials) in response to pain. Ji believes the finding could potentially lead to new treatments for pain, as well as new ways to predict the efficacy of already existing treatments based on PD-1 and PD-L1. "The response to cancer drugs can take a long time, weeks to months," he said. "The response to pain happens in minutes to hours." In the future, Ji would like to explore whether the mechanism uncovered in this study also applies to other immunotherapy treatments. He is also interested in working with clinicians to measure changes in patients' pain sensitivity after treatment, a first step toward developing a diagnostic test. The study was a collaboration between Duke University and two Chinese universities, Fudan University and Nantong University. Professor Yu-Qiu Zhang from Fudan University, the co-senior author of the paper, is a well-known expert in cancer pain. The lead author, Dr. Gang Chen, was an Assistant Professor at Duke and is now a Professor at Nantong. The research was supported by the National Institutes of Health (NS87988, DE17794, and DE22743), the National Science Fund of China (31420103903), and the National Research Foundation of Korea (2013R1A6A3A04065858) CITATION: "PD-L1 inhibits acute and chronic pain by suppressing nociceptive neuron activity via PD-1," Gang Chen, Yong Ho Kim, Hui Li, Hao Luo, Da-Lu Liu, Zhi-Jun Zhang, Mark Lay, Wonseok Chang, Yu-Qiu Zhang, and Ru-Rong Ji. Nature Neuroscience, May 22, 2017. DOI: doi:10.1038/nn.4571


Grant
Agency: European Commission | Branch: FP7 | Program: CSA-CA | Phase: INCO-2007-3.1.2 | Award Amount: 2.86M | Year: 2009

Strategic Objectives Assessed: Strengthening the ERA by integrating national and European S&T schemes through International Cooperation in S&T with Korea, with a specific focus on existing Competency Networks.


Grant
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: INCO.2013-2.1 | Award Amount: 1.99M | Year: 2013

The KONNECT project will strengthen STI cooperation between the EU and Republic of Korea, promoting innovation and the enhancement of communication for technology-related policy dialogue. This project brings together seven organizations from the EU and the Republic of Korea to improve and sustain communication between the two regions at the research and policy level and increase the expand the scope of STI networks and activities. The fulfilment of these objectives will improve the overall level of prosperity in both Europe and Korea and contribute to the resolution of natural and societal issues and threats facing the world. The main activities of the KONNECT project will work towards progressing research in four central fields of mutual interest: Information and Communications Technology (ICT), Nanosciences, Nanotechnologies, Materials, and New Production Technologies (NMP), Green Technology and Secure, Clean, and Efficient Energy (GT), and Biotechnologies (BT). The projects consortium will organise important activities within the set parameters of the project, and focus on key issues such as raising awareness for Horizon 2020, advancing innovation as well as R&D, and expanding joint activities under thematic areas. Due to the newly announced EU R&D Framework Programme (Horizon 2020) and Koreas upcoming government changeover in 2013, initiating new collaborative activities between the two sides takes on even greater importance. The KONNECT project will be committed to adhering to the following broad objectives: 1) Developing Knowledge-based Infrastructure, 2) Improving Strategic Communication, 3) Raising Awareness to Facilitate Cooperation between the EU and Korea, 4) Enhancing Networking between Science, Technology, and Innovation-focused Actors, and 5) Fostering Innovation-focused Joint Activities. This project will allow Korea to utilise its assets to assist the EU as it works towards achieving its goals for Europe 2020.


News Article | March 1, 2017
Site: www.eurekalert.org

ANN ARBOR -- Unavoidable vibrations, such as those on airplanes, cause rigid structures to age and crack, but researchers at the University of Michigan may have an answer for that--design them more like tooth enamel, which could lead to more resilient flight computers, for instance. Most materials that effectively absorb vibration are soft, so they don't make good structural components such as beams, chassis or motherboards. For inspiration on how to make hard materials that survive repeated shocks, the researchers looked to nature. "Artificial enamel is better than solid commercial and experimental materials that are aimed at the same vibration damping," said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Chemical Engineering. "It's lighter, more effective and, perhaps, less expensive." He and his team didn't settle on enamel immediately. They examined many structures in animals that had to withstand shocks and vibrations: bones, shells, carapaces and teeth. These living structures changed from species to species and over the eons. Tooth enamel told a different story. Under an electron microscope, it shared a similar structure whether it came from a Tyrannosaurus, a walrus, a sea urchin or Kotov himself (he contributed his own wisdom tooth to the effort). "To me, this is opposite to what's happening with every other tissue in the process of evolution," he said. "Their structures diversified tremendously but not the structure of enamel." Evolution had hit on a design that worked for pretty much everyone with teeth. And unlike bone, which can be repaired, enamel had to last the lifetime of the tooth--years, decades or longer still. It must withstand repeated stresses and general vibrations without cracking. Enamel is made of columns of ceramic crystals infiltrated with a matrix of proteins, set into a hard protective coating. This layer is sometimes repeated, made thicker in the teeth that have to be tougher. The reason why this structure is effective at absorbing vibrations, Kotov explained, is that the stiff nanoscale columns bending under stress from above create a lot of friction with the softer polymer surrounding them within the enamel. The large contact area between the ceramic and protein components further increases the dissipation of energy that might otherwise damage it. Bongjun Yeom, a postdoctoral researcher in Kotov's lab, recreated the enamel structure by growing zinc oxide nanowires on a chip. Then he layered two polymers over the nanowires, spinning the chip to spread out the liquid and baking it to cure the plastic between coats. It took 40 layers to build up a single micrometer, or one thousandth of a millimeter, of enamel-like structure. Then, they laid down another layer of zinc oxide nanowires and filled it in with 40 layers of polymer, repeating the whole process up to 20 times. Even molecular or nanoscale gaps between the polymer and ceramic would reduce the strength of material and the intensity of the friction, but the painstaking layering ensured the surfaces were perfectly mated. "The marvelous mechanical properties of biological materials stem from great molecular and nanoscale adaptation of soft structures to hard ones and vice versa," Kotov said. Kotov's group demonstrated that their synthetic tooth enamel approached the ability of real tooth enamel to defend itself from damage due to vibrations. Computer modeling of the synthetic enamel, performed by researchers at Michigan Technological University and the Illinois Applied Research Institute, confirmed that the structure diffused the forces from vibrations through the interaction between the polymer and columns. From the project's inception as a challenge from the Defense Advanced Research Projects Agency, Kotov worked with fellow materials heavyweights Ellen Arruda, U-M professor of mechanical engineering, and Anthony Waas, ­­the Felix Pawlowski Collegiate Professor Emeritus. Kotov hopes to see the synthetic enamel deployed in airplanes and other environments in which vibrations are inescapable, protecting structures and electronics. The challenge, he said, will be automating the production of the material. The paper is titled "Abiotic tooth enamel" and will be published in the journal Nature. Kotov is also a professor biomedical engineering, materials science and engineering, and macromolecular science and engineering. Arruda is also a professor of macromolecular science and engineering. Waas is also a professor emeritus of aerospace engineering and mechanical engineering. Yeom is now an assistant professor of chemical engineering at Myongji University in South Korea. This research was supported by the Defense Advanced Research Projects Agency, NextGen Aeronautics, National Science Foundation, Department of Defense and the National Research Foundation of Korea. The electron microscope used for the analysis was purchased with National Science Foundation grants.


Patent
National Research Foundation Of Korea | Date: 2014-06-09

A system and a method for objectively evaluating qualitative levels of academic journals in the field of science and engineering are disclosed. The system for evaluating journals includes: a winner or members paper database which includes information of papers published by a researcher who is awarded a prize or elected to a member of the academy in the field of science and engineering; a journal database which includes information of papers published in journals to be evaluated; a winner or members paper ratio evaluation section which calculates a winner or members paper ratio for the journals by using the information of papers of the journal database and the information of papers of the winner or members paper database; and a journal evaluation section which evaluates a degree of contribution of the journals in awarding the prize or electing to the member of the academy from the winner or members paper ratio calculated by the winner or members paper ratio evaluation section.

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