research
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Explanation for the polymerized nucleic acid enzyme's abnormal activation found
KAIST’s Professor Park Hyun Kyu of the Department of Bio Chemical Engineering revealed on the 23rd of December 2010 that his team had successfully developed the technology that uses the metal ions to control the abnormal activation of nucleic acids’ enzymes and using this, created a logic gate, which is a core technology in the field of future bio electrons.
The polymerized nucleic acid enzyme works to increase the synthesis of DNA and kicks into action only when the target DNA and primers form complimentary pairs (A and T, C and G).
Professor Park broke the common conception and found that it is possible for none complimentary pairs like T-T and C-C to initiate the activation of the enzyme and thus increase the nucleic acid production, given that there are certain metal ions present.
What Professor Park realized is that the enzymes mistake the uncomplimentary T-T and C-C pairs (with stabilized structures due to the bonding with mercury and silver ions) as being complimentary base pairs. Professor Park described this phenomenon as the “illusionary polymerase activity.”
The research team developed a logic gate based on the “illusionary polymerase activity’ phenomenon.” The logic gate paves the way to the development of future bio electron needed for bio computers and high performance memories.
Professor Park commented, “The research is an advancement of the previous research carried on about metal ions and nucleic acid synthesis. Our research is the first attempt at merging the concepts of the two previously separately carried out researches and can be adapted for testing presence of metal ions and development of a new single nucleotide polymorphic gene analysis technology.”
Professor Park added that, “Our research is a great stride in the field of nano scale electron element research as the results made possible the formation of accurate logic gates through relatively cost efficient and simple system designs.”
On a side note, the research was funded by Korea Research Foundation (Chairman: Park Chan Mo) and was selected as the cover paper for the December issue of ‘Angewandte Chemie International Edition’.
2011.01.18 View 10055 -
Rise of the mimic-bots that act like we do: Human-machine teamwork.
An online magazine, Technology Marketing Corporation, based in the UK published an article, dated January 8, 2011, on a robot research project led by Professor Jong-Hwan Kim from the Electrical Engineering Department. The article follows below:
Technology Marketing Corporation
[January 08, 2011]
Rise of the mimic-bots that act like we do Human-machine teamwork
(New Scientist Via Acquire Media NewsEdge) Rise of the mimic-bots that act like we doA robot inspired by human mirror neurons can interpret human gestures to learn how it should actNow follow meA robot inspired by human mirror neurons can interpret human gestures to learn how it should actA HUMAN and a robot face each other across the room. The human picks up a ball, tosses it towards the robot, and then pushes a toy car in the same direction.
Confused by two objects coming towards it at the same time, the robot flashes a question mark on a screen. Without speaking, the human makes a throwing gesture. The robot turns its attention to the ball and decides to throw it back.
In this case the robot"s actions were represented by software commands, but it will be only a small step to adapt the system to enable a real robot to infer a human"s wishes from their gestures.
Developed by Ji-Hyeong Han and Jong-Hwan Kim at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, the system is designed to respond to the actions of the person confronting it in the same way that our own brains do. The human brain contains specialised cells, called mirror neurons, that appear to fire in the same way when we watch an action being performed by others as they do when we perform the action ourselves. It is thought that this helps us to recognise or predict their intentions.
To perform the same feat, the robot observes what the person is doing, breaks the action down into a simple verbal description, and stores it in its memory. It compares the action it observes with a database of its own actions, and generates a simulation based on the closest match.
The robot also builds up a set of intentions or goals associated with an action. For example, a throwing gesture indicates that the human wants the robot to throw something back. The robot then connects the action "throw" with the object "ball" and adds this to its store of knowledge.
When the memory bank contains two possible intentions that fit the available information, the robot considers them both and determines which results in the most positive feedback from the human?- a smile or a nod, for example. If the robot is confused by conflicting information, it can request another gesture from the human. It also remembers details of each interaction, allowing it to respond more quickly when it finds itself in a situation it has encountered before.
The system should allow robots to interact more effectively with humans, using the same visual cues we use. "Of course, robots can recognise human intentions by understanding speech, but humans would have to make constant, explicit commands to the robot," says Han. "That would be pretty uncomfortable."Socially intelligent robots that can communicate with us through gesture and expression will need to develop a mental model of the person they are dealing with in order to understand their needs, says Chris Melhuish, director of the Bristol Robotics Laboratory in the UK. Using mirror neurons and humans" unique mimicking ability as an inspiration for building such robots could be quite interesting, he says.
Han now plans to test the system on a robot equipped with visual and other sensors to detect people"s gestures. He presented his work at the Robio conference in Tianjin, China, in December. nAs the population of many countries ages, elderly people may share more of their workload with robotic helpers or colleagues. In an effort to make such interactions as easy as possible, Chris Melhuish and colleagues at the Bristol Robotics Laboratory in the UK are leading a Europe-wide collaboration called Cooperative Human Robotic Interaction Systems that is equipping robots with software that recognises an object they are picking up before they hand it to a person. They also have eye-tracking technology that they use to monitor what humans are paying attention to. The goal is to develop robots that can learn to safely perform shared tasks with people, such as stirring a cake mixture as a human adds milk.
(c) 2011 Reed Business Information - UK. All Rights Reserved.
2011.01.10 View 9759 -
KAIST developed a plastic film board less sensitive to heat.
The research result was made the cover of magazine, Advanced Materials and is accredited to paving the way to commercialize flexible display screens and solar power cells.
Transparent plastic and glass cloths, which have a limited thermal expansion needed for the production of flexible display screens and solar power cells, were developed by Korean researchers.
The research, led by KAIST’s Professor Byoung-Soo Bae, was funded by the Engineering Research Center under the initiative of the Ministry of Education, Science and Technology and the National Research Foundation. The research result was printed as the cover paper of ‘Advanced Materials’ which is the leading magazine in the field of materials science.
Professor Bae’s team developed a hybrid material with the same properties as fiber glass. With the material, they created a transparent, plastic film sheet resistant to heat. Transparent plastic film sheets were used by researchers all over the world to develop devices such as flexible displays or solar power cells that can be fit into various living spaces. However, plastic films are heat sensitive and tend to expand as temperature increases, thereby making it difficult to produce displays or solar power cells.
The new transparent, plastic film screen shows that heat expansion index (13ppm/oC) similar to that of glass fiber (9ppm/oC) due to the presence of glass fibers; its heat resistance allows to be used for displays and solar power cells over 250oC.
Professor Bae’s team succeeded in producing a flexible thin plastic film available for use in LCD or AMOLED screens and thin solar power cells.
Professor Bae commented, “Not only the newly developed plastic film has superior qualities, compared to the old models, but also it is cheap to produce, potentially bringing forward the day when flexible displays and solar panels become commonplace. With the cooperation of various industries, research institutes and universities, we will strive to improve the existing design and develop it further.”
2011.01.05 View 13012 -
The KAIST & GIT team developed a power generation technology using bendable thin film nano-materials.
Figure description: Flexible thin film nanomaterials produce electricity.
Can a heart implanted micro robot operate permanently?
Can cell phones and tiny robots implanted in the heart operate permanently without having their batteries charged?
It might sound like science fiction, but these things seem to be possible in the near future. The team of Prof. Keon Jae Lee (KAIST, Dept. of Materials Science and Engineering) and Prof. Zhong Lin Wang (Georgia Institute of Technology, Dept. of Materials Science and Engineering) has developed new forms of highly efficient, flexible nanogenerator technology using the freely bendable piezoelectric ceramic thin film nano-materials that can convert tiny movements of the human body (such as heart beats and blood flow) into electrical energy.
The piezoelectric effect refers to voltage generation when pressure or bending strength is applied to piezoelectric materials. The ceramics, containing a perovskite structure, have a high piezoelectric efficiency. Until now, it has been very difficult to use these ceramic materials to fabricate flexible electronic systems due to their brittle property.
The research team, however, has succeeded in developing a bio-eco-friendly ceramic thin film nanogenerator that is freely bendable without breakdown.
Nanogenerator technology, a power generating system without wires or batteries, combines nanotechnology with piezoelectrics that can be used not only in personal mobile electronics but also in bio-implantable sensors or as an energy source for micro robots. Energy sources in nature (wind, vibration, and sound) and biomechanical forces produced by the human body (heart beats, blood flow, and muscle contraction/relaxation) can infinitely produce nonpolluting energy. (Nanogenerator produces electricity by external forces: http://www.youtube.com/watch?v=tvj0SsBqpBw)
Prof. Keon Jae Lee (KAIST) was involved in the first co-invention of “High Performance Flexible Single Crystal Electronics” during his PhD course at the University of Illinois at Urbana-Champaign. This nanogenerator technology, based on the previous invention, utilized the similar protocol of transferring ceramic thin film nano-materials on flexible substrates and produced voltage generation between electrodes.
Prof. Zhong Lin Wang (Georgia Tech, inventor of the nanogenerator) said, “This technology can be used to turn on an LED by slightly modifying circuits and operate touchable flexible displays. In addition, thin film nano-materials (‘barium titanate’) of this research have the property of both high efficiency and lead-free bio compatibility, which can be used in future medical applications.” This result is published in November online issue of ‘Nano Letters’ ACS journal.
<Video>
Youtube link: http://www.youtube.com/watch?v=tvj0SsBqpBw
Thin Film Nanogenerator produces electricity by external forces.
2010.11.23 View 14020 -
Nanowerk Spotlight: Bacteria as environmentally friendly nanoparticle factories, Sep. 24, 2010
The Nanowerk.com is a leading portal site for nanotechnology and nanosciences, which runs a daily news section called “Spotlight.” On September 24, 2010, the Spotlight published an article on the latest developments of the research by a KAIST team headed by Distinguished Professor Sang-Yup Lee of the Chemical and Bimolecular Engineering Department. For the article, please click the link below:
Nanowerk Spotlight: Bacteria as environmentally friendly nanoparticle factories, Sep. 24, 2010
By Michael Berger.
http://www.nanowerk.com/spotlight/spotid=18188.php
2010.09.25 View 10042
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"Supersolidity flows back," Nature, September 2, 2010
Supersolidity, discovered for the first time in 2004 by two physicists—one of them is Professor Eun-Seong Kim from the Department of Physics, KAIST—was discussed once again in the September 2, 2010 issue of Nature, an internationally well-known science journal.
The article mentioned “supersolidity” as one of the rare examples of quantum effects on a macroscopic scale, together with “superconductivity” and “superfluidity.” The phenomenon of supersolidity was evidenced by Professor Kim and his colleague through an experiment of placing helium-4 in a torsional oscillator under a low temperature.
The phenomenon, however, has been in debate among scientists in the physics community since the discovery, and Professor Kim has recently released his research results to further support his claim. For the full article, please click the link below:
http://www.nature.com/news/2010/100902/full/news.2010.443.html.
2010.09.08 View 9237
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Science News Issued on September 11, 2010: A matter of solidity
Science News, a bi-weekly news magazine of the Society for Science & the Public, published an extensive article on the issue of “supersolidity” discovered in helium-4.
Professor Eun-Seong Kim of the Physics Department, KAIST, is one of the scientists who discovered the phenomenon through an experiment of solid helium using a device called a torsional oscillator.
For the entire article, please click the link of
http://www.sciencenews.org/view/feature/id/62642/title/A_matter_of_solidity.
2010.09.02 View 10177
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Nanowire crystal transformation method was newly developed by a KAIST research team.
Figure 1
Schematic illustration of NW crystal transformation process. FeSi is converted to Fe3Si by high-temperature thermal annealing in diluted O2 condition and subsequent wet etching by 5% HF.
Figure 2
Low-resolution TEM images of FeSi; Fe3Si@SiO2 core—shell; Fe3Si NW after shell-etching; and Scale bars are 20 nm
Professor Bongsoo Kim of the Department of Chemistry, KAIST, and his research team succeeded to fabricate Heusler alloy Fe3Si nanowires by a diffusion-driven crystal structure transformation method from paramagnetic FeSi nanowires. This methodology is also applied to Co2Si nanowires in order to obtain metal-rich nanowires (Co) as another evidence of the structural transformation process. The newly developed nanowire crystal transformation method, Professor Kim said, would be valuable as a general method to fabricate metal-rich silicide nanowires that are otherwise difficult to synthesize.
Metal silicide nanowires are potentially useful in a wide array of fields including nao-optics, information technology, biosensors, and medicine. Chemical synthesis of these nanowires, however, is challenging due to the complex phase behavior of silicides.
The metal silicide nanowires are grown on a silicon substrate covered with a thin layer of silicon oxide via a simple chemical vapor deposition (CVD) process using single or multiple source precursors. Alternatively, the nanowires can be grown on the thin silicon oxide film via a chemical vapor transport (CVT) process using solid metal silicide precursors.
The CVT-based method has been highly effective for the syntheses of metal silicide NWs, but changing the composition of metal silicide NWs in a wider range, especially achieving a composition of a metal to silicon, has been quite difficult.
Thus, developing efficient and reliable synthetic methods to adjust flexibly the elemental compositions in metal silicide NWs can be valuable for the fabrication of practical spintronic and neonelectronic devices.
Professor Kim expliained, “The key concept underlying this work is metal-enrichment of metal silicide NWs by thermal diffusion. This conversion method could prove highly valuable, since novel metal-rich silicide NWs that are difficult to synthesize but possess interesting physical properties can be fabricated from other metal silicide NWs.”
The research result was published in Nanao Letters, a leading peer-reviewed journal, and posted online in early August 2010.
2010.08.25 View 10461 -
An internationally renowned academic journal published the research result produced by a KAST research team on its cover.
Fc DAAP VEGF-Trap
Photograph showing the gross features of tumor growth along the mesentery-intestinal border. T: tumor. Scale bars represent 5 mm.
Professor Gou-Young Koh of the Biological Sciences Department, KAIST, and his research team published their research result in Cancer Cell, a peer-review scientific journal, as a cover article dated August 17, 2010. It is the first time for the journal to pick up a paper written by a Korean research team and publish it as the cover.
It has been known that a vascular growth factor (VEGF) is closely related to the growth of a tumor. The research team recently discovered that in addition to VEGF, another growth factor, angiopoietin-2 (Ang2), is also engaged with the increase of tumors.
Professor Koh said, “VEGF and the angiopoietins play critical roles in tumor progression and metastasis, and a single inhibitor targeting both factors have not been available.”
The team led by Professor Koh has developed a double anti-angiogenic protein (DAAP) that can simultaneously bind VEGF-A and the angiopoietins and block their actions.
Professor Koh said in his paper, “DAAP is a highly effective molecule for regressing tumor angiogenesis and metastasis in implanted and spontaneous solid tumor; it can also effectively reduce ascites formation and vascular leakage in an ovarian carcinoma model. Thus, simultaneous blockade of VEGF-A and angiopoietins with DAAP is an effective therapeutic strategy for blocking tumor angiogenesis, metastasis, and vascular leakage.”
So far, cancer patients have received Avastin, anticancer drug, to inhibit VEGF, but the drug has not successfully restrained the growth of cancer tumors and brought to some of the patients with serious side effects instead.
Professor Koh said, “DAAP will be very effective to control the expansion of tumor growth factors, which will open up a new possibility for the development of more helpful cancer medicine with low side effects.”
2010.08.20 View 11452 -
Nature Photonics, a peer-reviewed scientific journal, released a paper written by a KAIST research team on the time-of-flight measurement.
Professor Seung-Woo Kim of the Mechanical Engineering Department, KAIST, and his research team published the result of their study on the measurement of 1 nanometer (nm) precision.
“The time-of-flight of light pulses has long been used as a direct measure of distance, but state-of-the-art measurement precision using conventional light pulses or microwaves peaks at only several hundreds of micrometers. Here, we improve the time-of-flight precision to the nanometer regime by timing femtosecond pulses through phase-locking control of the pulse repetition rate using the optical cross-correlation technique,” Professor Kim said.
According to the experiment conducted by the research team, “An Allan deviation of 117 nm in measuring a 700m distance in air at a sampling rate of 5 millisecond (ms) once the pulse repetition is phased-locked, which reduces to 7 nm as the averaging time increases to 1 second (s).”
When measuring an object located in a far distance, a laser beam is projected to the object, and the reflected light is analyzed; the light is then converted into an electric signal to calculate the distance. In so doing, Professor Kim said, the conventional method of measurement creates at least 1 mm of deviation.
He argues, “This enhanced capability is maintained at long range without periodic ambiguity, and is well suited to lidar applications. This method could also be applied to future space missions involving formation-flying satellites for synthetic aperture imaging and remote experiments related to general relativity theory."
Nature Photonics published the article online on August 8, 2010.
2010.08.18 View 10900 -
Bioengineers develop a new strategy for accurate prediction of cellular metabolic fluxes
A team of pioneering South Korean scientists has developed a new strategy for accurately predicting cellular metabolic fluxes under various genotypic and environmental conditions. This groundbreaking research is published in the journal Proceedings of the National Academy of Sciences of the USA (PNAS) on August 2, 2010.
To understand cellular metabolism and predict its metabolic capability at systems-level, systems biological analysis by modeling and simulation of metabolic network plays an important role. The team from the Korea Advanced Institute of Science and Technology (KAIST), led by Distinguished Professor Sang Yup Lee, focused their research on the development of a new strategy for more accurate prediction of cellular metabolism.
“For strain improvement, biologists have made every effort to understand the global picture of biological systems and investigate the changes of all metabolic fluxes of the system under changing genotypic and environmental conditions,” said Lee. The accumulation of omics data, including genome, transcriptome, proteome, metabolome, and fluxome, provides an opportunity to understand the cellular physiology and metabolic characteristics at systems-level. With the availability of the fully annotated genome sequence, the genome-scale in silico (means “performed on computer or via computer simulation.”) metabolic models for a number of organisms have been successfully developed to improve our understanding on these biological systems. With these advances, the development of new simulation methods to analyze and integrate systematically large amounts of biological data and predict cellular metabolic capability for systems biological analysis is important.
Information used to reconstruct the genome-scale in silico cell is not yet complete, which can make the simulation results different from the physiological performances of the real cell. Thus, additional information and procedures, such as providing additional constraints (constraint: a term to exclude incorrect metabolic fluxes by restricting the solution space of in silico cell) to the model, are often incorporated to improve the accuracy of the in silico cell.
By employing information generated from the genome sequence and annotation, the KAIST team developed a new set of constraints, called Grouping Reaction (GR) constraints, to accurately predict metabolic fluxes. Based on the genomic information, functionally related reactions were organized into different groups. These groups were considered for the generation of GR constraints, as condition- and objective function- independent constraints. Since the method developed in this study does not require complex information but only the genome sequence and annotation, this strategy can be applied to any organism with a completely annotated genome sequence.
“As we become increasingly concerned with environmental problems and the limits of fossil resources, bio-based production of chemicals from renewable biomass has been receiving great attention. Systems biological analysis by modeling and simulation of biological systems, to understand cellular metabolism and identify the targets for the strain improvement, has provided a new paradigm for developing successful bioprocesses,” concluded Lee. This new strategy for predicting cellular metabolism is expected to contribute to more accurate determination of cellular metabolic characteristics, and consequently to the development of metabolic engineering strategies for the efficient production of important industrial products and identification of new drug targets in pathogens.”
2010.08.05 View 12415 -
Native-like Spider Silk Produced in Metabolically Engineered Bacterium
Microscopic picture of 285 kilodalton recombinant spider silk fiber
Researchers have long envied spiders’ ability to manufacture silk that is light-weighted while as strong and tough as steel or Kevlar. Indeed, finer than human hair, five times stronger by weight than steel, and three times tougher than the top quality man-made fiber Kevlar, spider dragline silk is an ideal material for numerous applications. Suggested industrial applications have ranged from parachute cords and protective clothing to composite materials in aircrafts. Also, many biomedical applications are envisioned due to its biocompatibility and biodegradability.
Unfortunately, natural dragline silk cannot be conveniently obtained by farming spiders because they are highly territorial and aggressive. To develop a more sustainable process, can scientists mass-produce artificial silk while maintaining the amazing properties of native silk? That is something Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, the Republic of Korea, and his collaborators, Professor Young Hwan Park at Seoul National University and Professor David Kaplan at Tufts University, wanted to figure out. Their method is very similar to what spiders essentially do: first, expression of recombinant silk proteins; second, making the soluble silk proteins into water-insoluble fibers through spinning.
For the successful expression of high molecular weight spider silk protein, Professor Lee and his colleagues pieced together the silk gene from chemically synthesized oligonucleotides, and then inserted it into the expression host (in this case, an industrially safe bacterium Escherichia coli which is normally found in our gut). Initially, the bacterium refused to the challenging task of producing high molecular weight spider silk protein due to the unique characteristics of the protein, such as extremely large size, repetitive nature of the protein structure, and biased abundance of a particular amino acid glycine. “To make E. coli synthesize this ultra high molecular weight (as big as 285 kilodalton) spider silk protein having highly repetitive amino acid sequence, we helped E. coli overcome the difficulties by systems metabolic engineering,” says Sang Yup Lee, Distinguished Professor of KAIST, who led this project. His team boosted the pool of glycyl-tRNA, the major building block of spider silk protein synthesis. “We could obtain appreciable expression of the 285 kilodalton spider silk protein, which is the largest recombinant silk protein ever produced in E. coli. That was really incredible.” says Dr. Xia.
But this was only step one. The KAIST team performed high-cell-density cultures for mass production of the recombinant spider silk protein. Then, the team developed a simple, easy to scale-up purification process for the recombinant spider silk protein. The purified spider silk protein could be spun into beautiful silk fiber. To study the mechanical properties of the artificial spider silk, the researchers determined tenacity, elongation, and Young’s modulus, the three critical mechanical parameters that represent a fiber’s strength, extensibility, and stiffness. Importantly, the artificial fiber displayed the tenacity, elongation, and Young’s modulus of 508 MPa, 15%, and 21 GPa, respectively, which are comparable to those of the native spider silk.
“We have offered an overall platform for mass production of native-like spider dragline silk. This platform would enable us to have broader industrial and biomedical applications for spider silk. Moreover, many other silk-like biomaterials such as elastin, collagen, byssus, resilin, and other repetitive proteins have similar features to spider silk protein. Thus, our platform should also be useful for their efficient bio-based production and applications,” concludes Professor Lee.
This work is published on July 26 in the Proceedings of the National Academy of Sciences (PNAS) online.
2010.07.28 View 16824