-
Recombinant E. Coli As a Biofactory for the Biosynthesis of Diverse Nanomaterials
(Distinguished Professor Lee and PhD candidate Choi)
A metabolic research group at KAIST and Chung-Ang University in Korea has developed a recombinant E. coli strain that biosynthesizes 60 different nanomaterials covering 35 elements on the periodic table. Among the elements, the team could biosynthesize 33 novel nanomaterials for the first time, advancing the forward design of nanomaterials through the biosynthesis of various single and multi-elements.
The study analyzed the nanomaterial biosynthesis conditions using a Pourbaix diagram to predict the producibility and crystallinity. Researchers studied a Pourbaix diagram to predict the stable chemical species of each element for nanomaterial biosynthesis at varying levels of reduction potential (Eh) and pH. Based on the Pourbaix diagram analyses, the initial pH of the reaction was changed from 6.5 to 7.5, resulting in the biosynthesis of various crystalline nanomaterials that were previously amorphous or not synthesized.
This strategy was extended to biosynthesize multi-element nanomaterials. Various single and multi-element nanomaterials biosynthesized in this research can potentially serve as new and novel nanomaterials for industrial applications such as catalysts, chemical sensors, biosensors, bioimaging, drug delivery, and cancer therapy.
A research group consisting of PhD candidate Yoojin Choi, Associate Professor Doh Chang Lee, and Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering at KAIST and Associate Professor Tae Jung Park of the Department of Chemistry at Chung-Ang University reported the synthesis. This study, entitled “Recombinant Escherichia coli as a biofactory for various single- and multi-element nanomaterials,” was published online in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) on May 21.
A recent successful biosynthesis of nanomaterials under mild conditions without requiring physical and chemical treatments has triggered the exploration of the full biosynthesis capacity of a biological system for producing a diverse range of nanomaterials as well as for understanding biosynthesis mechanisms for crystalline versus amorphous nanomaterials.
There has been increased interest in synthesizing various nanomaterials that have not yet been synthesized for various applications including semiconducting materials, enhanced solar cells, biomedical materials, and many others. This research reports the construction of a recombinant E. coli strain that co-expresses metallothionein, a metal binding protein, and phytochelatin synthase that synthesizes the metal-binding peptide phytochelatin for the biosynthesis of various nanomaterials. Subsequently, an E. coli strain was engineered to produce a diverse range of nanomaterials, including those never biosynthesized before, by using 35 individual elements from the periodic table and also by combining multi-elements.
Distinguished Professor Lee said, “An environmentally-friendly and sustainable process is of much interest for producing nanomaterials by not only chemical and physical methods but biological synthesis. Moreover, there has been much attention paid to producing diverse and novel nanomaterials for new industrial applications. This is the first report to predict the biosynthesis of various nanomaterials, by far the largest number of various single- and multi-elements nanomaterials. The strategies used for nanomaterial biosynthesis in this research will be useful for further diversifying the portfolio of nanomaterials that can be manufactured.”
Figure: The biosynthesis of diverse nanomaterials using recombinant E. coli. This schematic diagram shows the overall conceptualization of the biosynthesis of various single and multi-element nanomaterials using recombinant E. coli under incubation with corresponding elemental precursors. The 35 elements that were tested to biosynthesize nanomaterials are shown in black circles on the periodic table.
2018.05.23 View 11553 -
A High-Performance and Cost Effective Hydrogen Sensor
(Research team of Professor Park, Professor Jung, and research fellow Gao Min)
A KAIST research team reported a high-performance and cost effective hydrogen sensor using novel fabrication process based on the combination of polystyrene nanosphere lithography and semiconductor microfabrication processes.
The research team, led by Professor Inkyu Park in the Department of Mechanical Engineering and Professor Yeon Sik Jung in the Department of Materials Science and Engineering, fabricated a nanostructured high-performance hydrogen gas sensor based on a palladium-decorated silicon nanomesh structure made using a polystyrene nanosphere self-assembly method. Their study was featured as the front cover article of journal “Small” (Publisher: Wiley-VCH) on March 8, 2018.
The nanosphere lithography method utilizes the self-assembly of a nanosphere monolayer. This could be an alternative choice for achieving uniform and well-ordered nanopatterns with minimum sub-10 nanometer dimensions. The research team said that the small dimensions of the silicon enhanced the palladium-gating effect and thus dramatically improved the sensitivity.
Hydrogen gas is widely considered to be one of the most promising next-generation energy resources. Also, it is a very important material for various industrial applications such as hydrogen-cooled systems, petroleum refinement, and metallurgical processes. However, hydrogen, which is highly flammable, is colorless and odorless and thus difficult to detect with human senses. Therefore, developing hydrogen gas sensors with high sensitivity, fast response, high selectivity, and good stability is of significant importance for the rising hydrogen economy.
Silicon nanowire-based devices have been employed as efficient components in high-performance sensors for detecting gases and other chemical and biological components. Since the nanowires have a high surface-to-volume ratio, they respond more sensitively to the surrounding environment.
The research team’s gas sensor shows dramatically improved hydrogen gas sensitivity compared with a silicon thin film sensor without nanopatterns. Furthermore, a buffered oxide etchant (BOE) treatment of the silicon nanomesh structure results in an additional performance improvement through suspension of nanomesh strutures from the substrate and surface roughening. The sensor device shows a fast hydrogen response (response time < 5 seconds) and 10 times higher selectivity to hydrogen gas among other gases. Their sensing performance is stable and shows repeatable responses in both dry and high-humidity ambient environments.
Professor Park said that his approach will be very useful for the fabrication of low-cost, high-performance sensors for chemical and biological detection with applications to mobile and wearable devices in the coming era of internet of things (IoTs).
(Figure 1: The front cover image of Small dated on March 8.)
(Figure 2: Gas sensor responses upon the exposure to H2 at various concentrations.)
2018.05.21 View 9377 -
Platinum Catalyst Has Price Lowed and Durability Doubled
(Professor Cho in the Department of Materials Science and Engineering)
Professor EunAe Cho in the Department of Materials Science and Engineering reported a fuel cell catalyst that shows 12 times higher performance and twice the durability than previously used platinum catalyst.
Fuel cells, eco-friendly power generators, are said to be running air purifiers. A hydrogen vehicle powered by fuel cells can allegedly purify more than 98 percent of the particulate matter and ultrafine particles from the amount of air that 70 adults breathe.
Despite this peculiarity, the high price of platinum, which is used as an electrode catalyst, remains a big challenge to accelerating commercialization. In addition, recently developed ‘nano-structured platinum catalysts’ have not yet commercialized due to its meager oxygen reduction reaction and durability in fuel cell.
Addressing all those challenges, Professor Cho’s team reported a platinum catalyst costing 30 percent less but boasting 12 times higher performance.
The research team, to this end, combined the platinum with nickel, then applied various metallic elements for making the most efficient performance. Among others, they found that the addition of gallium can modulate the oxygen intermediate binding energy, leading to enhanced catalytic activity of the oxygen reduction reaction.
They made octahedron nanoparticle platinum-nickel alloy and could efficiently achieve 12-times high performance with the platinum catalyst by adding gallium to the surface of octahedron.
Existing fuel cell catalysts have issues in practical fuel cell applications. However, Professor Cho’s team experimentally proved the high performance of the catalyst even in the fuel cell, and is expected to be practically applied to the existing procedure.
First author JeongHoon Lim said their work demonstrates the gallium-added octahedral nanoparticles can be utilized as a highly active and durable oxygen reduction reaction catalyst in practical fuel cell applications. It will make it feasible for the mass production of the catalysts.
Professor Cho also said, “Our study realized the two main goals: an affordable price and increased performance of fuel cells. We hope this will make a contribution to the market competitiveness of fuel cell electric vehicles.”
This research was described in Nano Letters in April and was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), the National Research Foundation (NRF), and the Agency for Defense Development (ADD).
(Figure: HAADF STEM images with EDX analyses and line scanning profiles of (a) Ga-PtNi/C and (b) PtNi/C during the voltage-cycling tests. The composition changes of Ni, Pt, and Ga atoms in the nanoparticles were determined by EDX (inset in the EDX mapping results)).
2018.05.15 View 7631 -
Capillary Forces at Work for Lithium-Sulfur Batteries
Professor Do Kyung Kim from the KAIST Department of Materials Science and Engineering and his team succeeded in developing high-areal-capacity lithium sulfur batteries (Li-S batteries) by capturing polysulfide with carbon nanofibers. This research will provide new batteries to replace existing lithium rechargeable batteries, shifting the commercialization of related technologies ahead.
Electrical vehicles and large-scale energy storage systems necessitate the development of batteries with high energy density and cost effectiveness, and Li-S batteries are known to be one of the promising alternatives to the predominant lithium ion batteries.
With six times as much energy density, Li-S batteries theoretically thrust electric vehicle to twice the distance of lithium ion batteries. Therefore, they have been spotlighted as next-generation lithium rechargeable batteries because they can go up to 400km once charged.
However, several issues make it challenging to readily commercialize Li-S batteries. The low electrical conductivity of sulfur, volumetric expansion and contraction of the battery during charge and discharge, and permanent damage of the electrode caused by the dissolution of the lithium polysulfide into the electrolyte – known as the “shuttle effect” – are three of the biggest obstacles to commercial-grade Li-S batteries.
While there have been numerous attempts to curb, avoid, or alleviate these issues — such as the physical encapsulation of sulfur using various metal oxides or carbonaceous matrices — most of them entail utilizing zero-dimensional (0D) carbon materials. This encapsulation method has been somewhat effective in enhancing the electrical conductivity of sulfur while simultaneously tolerating some volumetric alterations and suppressing the shuttle effect. The downside of 0D carbon material-based encapsulation methods is their complicated synthetic processing and the limited mass loading of sulfur.
With this in mind, the team set out to employ one-dimensional (1D) carbon materials instead. Unlike the 0D case, 1D carbon materials render a large surface area and a long-range conduction path for electrons and lithium ions. Being 1D also solves the undesirable high-contact resistance problem frequently encountered by 0D carbon material-based encapsulation.
The key to developing the proposed material was to exploit the capillary force to decrease the energy associated with the dissolution of polysulfides. As such, carbon nanofibers (CNFs) were found to be suitable for high-areal-capacity lithium-sulfur batteries since capillary force acting between CNFs can take advantage of the high electrical conductivity with the suppressed dissolution of sulfides.
The research findings show that sulfur was successfully contained in between the CNFs by wetting due to the capillary force without the need for complicated synthetic processing, as in the 0D case. The research results indicate that the sulfur contained per unit area (mg/cm2) is five times greater for the newly implemented method, which then enabled the lithium-sulfur battery to achieve an areal capacity of 7 mAh/cm2, which amounts to as much as at most seven times that of conventional lithium ion batteries.
First author Jong Hyuk Yun stated that the unprecedented methods utilized in this study will help further and widen the progress of lithium batteries in general. Meanwhile, Professor Kim said, “This study brought us closer to commercial-grade high-capacity Li-S batteries, which are applicable for a wide variety of products, including electric vehicles, unmanned aerial vehicles (UAVs), and drones.”
This research, led by PhD candidate Yun, was published in the 18th issue of this year’s Nano Letters.
Figure 1. Electrochemical reaction leading to the containment of the sulfur within the carbon nanofiber and the corresponding specific capacity of the battery over a number of charge-discharge cycles
Figure 2. SEM images of the first discharged electrode containing lithium sulfide at the junction between the nanofibers, and the first charged electrode
Figure 3. carbon nanofiber effectively absorbing liquid based lithium polysulfide
2018.05.14 View 7996 -
New Material for Generating Energy-Efficient Spin Currents
(Professor Byong-Guk Park (left) and Professor Kab-Jin Kim)
Magnetic random access memory (MRAM) is emerging as next-generation memory. It allows information to be kept even without an external power supply and its unique blend of high density and high speed operation is driving global semiconductor manufacturers to develop new versions continuously.
A KAIST team, led by Professor Byong-Guk Park in the Department of Materials Science and Engineering and Professor Kab-Jin Kim in the Department of Physics, recently has developed a new material which enables the efficient generation of a spin current, the core part of operating MRAM. This new material consisting of ferromagnet-transition metal bilayers can randomly control the direction of the generated spin current unlike the existing ones.
They also described a mechanism for spin-current generation at the interface between the bottom ferromagnetic layer and the non-magnetic spacer layer, which gives torques on the top magnetic layer that are consistent with the measured magnetization dependence.
When applying this to spin-orbit torque magnetic memory, it shows the increased efficiency of spin torque and generation of the spin current without an external magnetic field. High-speed operation, the distinct feature of spin-orbit torque-based MRAM that carries its non-volatility, can significantly reduce the standby power better than SRAM.
This new material will expect to speed up the commercialization of MRAM. The research team said that this magnetic memory will further be applied to mobile, wearable, and IoT devices.
This study, conducted in collaboration with Professor Kyung-Jin Lee from Korea University and Dr. Mark Stiles from the National Institute of Standards and Technology in the US, was featured in Nature Materials in March. The research was funded by the Creative Materials Discovery Program of the Ministry of Science and ICT.
(Figure: Ferromagnet-transition metal bilayers which can randomly control the direction of the generated spin current)
2018.05.11 View 10230 -
Yoon Ki Hong Named 2018 Jeong Hun Cho Awardee
(From left: PhD candidate Seungkwan Baek from the Department of Aerospace Engineering, Dr. Yoon Ki Hong from ADD, PhD candidate Wonhee Choi from the School of Mechanical Engineering at Korea University, and Jaehun Lee from Kongju National University High School)
Dr. Yoon Ki Hong from the Agency of Defense Development (ADD) was named the 2018 recipient of the Jong-Hoon Cho Award. The award recognizes outstanding young scientists in the field of aerospace engineering annually. The recipient of this award receives a 25 million KRW prize.
The Award Committee said that Dr. Hong has achieved outstanding work in the field of aerospace engineering. In particular, he conducted research on designing an air heating device which is the crucial component for ground experimental equipment. It is required for testing and evaluating supersonic vehicles’ structural strength tests using technology cannot be imported. In cooperation with his colleagues, he succeeded in developing an air heating device, a feat that has only been accomplished by developed countries. He also verified its operational performance.
Moreover, he received the best paper award from Korean Federation of Science and Minister of Defense Acquisition Program Administration’s Prize.
The award was endowed by the family of the late PhD candidate Jeong Hun Cho, who died in a rocket lab accident in the Department of Aerospace Engineering in 2003. Cho was posthumously conferred an honorary doctorate degree.
In Cho’s memory, his father established the ‘Jeong Hun Cho Award and Scholarship’. Since 2005, the scholarship annually selects three young scholars specializing in aerospace engineering from Cho’s alma maters of KAIST, Korea University, and Kongju National University High School.
In addition to Dr. Hong, the Award Committee chose three students for scholarships: PhD candidate Seungkwan Baek from the Department of Aerospace Engineering, PhD candidate Wonhee Choi from the School of Mechanical Engineering at Korea University, and Jaehun Lee from Kongju National University High School.
2018.05.11 View 9875 -
The First Recipient of the KPS Award in Plasma Physics
( Research Professor Sanghoo Park)
Research Professor Sanghoo Park received the Young Researcher Award in Plasma Physics during the Korean Physical Society (KPS)’s Spring Meeting from April 25 to 27.
He is a KAIST graduate with a PhD in Physics and currently holds the position of research professor in the Department of Nuclear and Quantum Engineering.
The Young Researcher Award in Plasma Physics is given to a specialist in plasma who has the potential to make a contribution to plasma and accelerator physics in Korea.
Professor Park has gained recognition for his work, including awards, publications in 24 journals, and 12 technical patent registrations of plasma, which led to his selection as the recipient of this award.
He is now conducting a leading role in this field nationally and internationally by delving into the study of partially-ionized plasma.
Professor Park said, “It is my great honor to become the first recipient of the Young Researcher Award in Plasma Physics. I will continue to engage in research to develop the field of plasma in Korea.”
2018.05.08 View 6761 -
Park Chosen for Principality of Monaco/ITER Postdoctoral Fellowship
(Jaesun Park in the Integrated Master's and Doctoral Degree Program )
Jaesun Park from the Department of Physics, was selected as a Principality of Monaco/ITER Postdoctoral Fellowship recipient.
This program was established by the Principality of Monaco and an international organization, ITER, in January 2008 to support postdoctoral researchers who will be working for ITER. It is a relatively competitive program because it chooses only five people every two years.
The selected postdoctoral researchers will be working for ITER for two years while conducting research projects with outstanding researchers in the field of nuclear fusion.
ITER, one of the most ambitious energy projects, was launched in 1985 with the purpose of carrying out joint research on nuclear fusion energy. Currently, about 800 people are working for this organization.
Seven ITER member countries (i.e. Korea, the European Union, the United States, China, Japan, Russia, and India) are sharing the expenses and engaging in mega-scale science projects. Korea shares 9.1% (20 billion Euro) of the total construction costs of ITER experimental devices.
Park will begin his duties in early 2019.
2018.05.04 View 9129 -
Professor Hee-Sung Park Named Scientist of May
(Professor Hee-Sung Park)
Professor Hee-Sung Park from the Department of Chemistry was named ‘Scientist of May’ sponsored by the Ministry of Science and ICT and the National Research Foundation of Korea. Professor Park was honored in recognition of his developing a tool to engineer designer proteins via diverse chemical modifications. This approach provides a novel platform for investigating numerous diseases such as cancer and dementia.
His research focuses on the production of synthetic proteins and the generation of diverse protein functions as well as the designing and engineering of new translation machinery for genetic code expansion, and the application of synthetic biology techniques for basic cell biology and applied medical science.
Post-translational modifications (PTMs) are constantly taking place during or after protein biosynthesis. PTMs play a vital role in expanding protein functional diversity and, as a result, critically affect numerous biological processes. Abnormal PTMs have been known to trigger various diseases including cancer and dementia. Therefore, this technology enables proteins to reproduce with specific modifications at selected residues and will significantly help establish experimental strategies to investigate fundamental biological mechanisms including the development of targeted cancer therapies.
Professor Park also received 10 million KRW in prize money.
2018.05.04 View 10152 -
Undergrad's Paper Chosen as the Cover Article in Soft Matter
(from left: Research Professor KyuHan Kim and Undergrad Student Subeen Kim)
A KAIST undergraduate student, Subeen Kim, had his paper chosen as the cover article in an international journal during his senior year.
There have been an increasing number of undergraduate students who were published as the first author because the KAIST Undergraduate Research Participation program allows more active research participation by undergraduate students.
Through URP, Kim successfully published his paper in the internationally-renowned journal, Soft Matter, which is published by the Royal Society of Chemistry, and it was chosen as the cover article of that journal in February 2018.
This publication means a lot to him because he designed the cover image himself, based on his imagination and observations.
His research is about controllable one-step double emulsion formation. Double emulsion is a system in which dispersed droplets contain additional immiscible liquid droplets.
Having great retention ability, double emulsion has been used in various applications in the food industry, in cosmetics, and for drug delivery. Nevertheless, two-step emulsification is a conventional approach to produce double emulsions that typically leads to partial destabilization of the emulsion formed during the initial stage. Hence, it does not ensure the stability of a double emulsion. On the other hand, a microfluidic approach with various flow-focusing techniques has been developed, but it has low production efficiency and thus limited industrial applications.
Kim’s results came from the process of phase inversion to solve this problem. He identified the instant formation of double emulsions during the process of phase inversion. Based on this finding, he proposed criteria to achieve high stability of double emulsion.
Through constant research, he developed a quite general method using a combination of an oil soluble poly methyl methacrylate (PMMA) and hydrophobic silica nanoparticle (HDK H18). This new method enables one-step and stable production of double emersions in a stable manner. It also allows control of the number and the volume of inner oil droplets inside the outer water droplets by adjusting PMMA and HDK H18.
Kim enrolled at KAIST as a KAIST Presidential Fellowship and Presidential Science Scholarship in 2014. While studying both chemical and biomolecular engineering and chemistry he has been developing his hypothesis and conducting research.
He was able to begin conducting research because he has taken part in URP projects twice. In his sophomore year, he studied the formation of high internal phase double emulsions. After one year, he conducted research to produce superabsorbent resins, which are the base material for diapers, by using colloid particles. Using partial research outcomes, he published his paper in Nature Communications as a second author.
Kim said, “Double majoring the chemical and biomolecular engineering and chemistry has helped me producing this outcome. I hope that this research contributes to commercializing double emulsions. I will continue to identify accurate principles to produce chemicals that can be controlled exquisitely.”
Figure 1. The cover article of Soft Matter
2018.05.03 View 10878 -
Cross-Generation Collaborative Labs Open
KAIST opened two cross-generation collaborative labs last month. This novel approach will pair up senior and junior faculty members for sustaining research and academic achievements even after the senior researcher retires.
This is one of the Vision 2031 innovation initiatives established to extend the spectrum of knowledge and research competitiveness. The selected labs will be funded for five years and the funding will be extended if necessary. KAIST will continue to select new labs every year.
A five-member selection committee including the Nobel Laureates Professor Klaus Von Klitzing at the Max-Planck Institute for Solid State Research and Dr. Kurt Wüthrich from ETH Zürich selected the first two labs with senior-junior pairs in March.
(Two renowned scholars' Cross-Generation Collaborative Labs which opened last month.
Distinguished Professor Lee's lab (above) andChair Professor Sung's lab)
Both labs are run by world-renowned scholars: the Systems Metabolic Engineering and Systems Healthcare Laboratory headed by Distinguished Professor Sang-Yup Lee in the Department of Chemical and Biomolecular Engineering and the Acousto-Microfluidics Research Center for Next-Generation Healthcare led by Chair Professor Hyung Jin Sung in the Department of Mechanical Engineering.
Distinguished Professor Lee will be teamed up with Professor Hyun Uk Kim, and their lab aims to mass produce new eco-friendly chemical materials as well as higher-value-added materials which will be used for medicine. The new platform technologies created in the lab are expected to provide information which will benefit human healthcare.
Meanwhile, the Acousto-Microfluidics Research Center for Next-Generation Healthcare will team up with Professors Hyoungsoo Kim and Yeunwoo Cho under Chair Professor Sung. The lab will conduct research on controlling fluids and objects exquisitely on a micro-nano scale by using high-frequency acoustic waves. The lab plans to develop a next-generation healthcare platform for customized diagnoses as well as disease treatment.
KAIST President Sung-Chul Shin, who introduced this novel idea in his research innovation initiative, said that he hopes the Cross-Generation Collaborative Labs will contribute to honoring senior scholars’ research legacies and passing knowledge down to junior researchers in order to further develop their academic achievements. He said, “I sincerely hope the labs will make numerous research breakthroughs in the very near future.”
2018.05.03 View 11864 -
Escalation of Competition Leads to Conflict in Competitive Networks of F1 Drivers
(Professor Wonjae Lee at the Graduate School of Culture Technology)
A new study has revealed that people with similar social status in similar age groups are more likely to clash with each other. This rivalry could likely lead to taking more risks in fair weather conditions.
Competition, while is often seen as beneficial, can escalate into destructive conflict. This occurs, for instance, when athletes sabotage each other or when rival executives get caught up in a career-derailing fight. These escalations, which lead to conflict, are especially likely among similar-status competitors, who are fraught with discordant understandings of who is superior to whom.
A research team of KAIST, the US Treasury, INSEAD, and the European School of Management and Technology (ESMT) examined the link between status similarity and conflict as well as the conditions under which this link holds by using panel data on Formula 1 races from 1970 through 2014. For the study, the research team analyzed a total of 506 collision cases by 355 F1 drivers over 45 years.
The team found that similar-status F1 drivers are more prone to collide, especially when they are age-similar, performing well, and feeling safe. When these boundary conditions are met, structural equivalence likely triggers antagonism among interactants.
This research deepens the understanding of when violent conflict emerges and when prevention efforts are called for. Professor Lee from the Graduate School of Culture Technology at KAIST said, “People are not sure about their identity when facing competitors of a similar status. People tend to confirm their own stature by beating an opponent.”
The team investigated the factors that escalate competition into dangerous conflict. Recently, sociological theorizing claims that such escalations are particularly likely in pairs of structurally equivalent actors who have the same relations with the same third parties. Using the F1 data, the research team modeled the probability that two drivers would collide on a racetrack as a function of their structural equivalence in a dynamic network of competitive relationships.
Professor Lee added, “We fully understand that the drivers who ranked first and second are likely to have more conflict because they meet more frequently and know each other well. We also regulated all those conditions and confirmed that our hypothesis worked right throughout the data analysis.”
Professor Lee, who wrote his doctoral thesis on tennis tournaments for identifying the ideal organizational structure, said that sports tournaments would be best optimized for comprehending the nature of organizational structures. Tournaments, even those with rankings based on objective criteria, are in fact intensely social. However, most prior empirical work in this area has relied only on official information on competitors’ performance, thus failing to capture the important elements of past competitive encounters.
“It is not so easy to obtain data on rivalries and conflicts inside an organization. However, in sports, the performances of athletes are all recorded and the data can be utilized as a very objective methodology for understanding social relations and their structural affects.
Official positions in tournaments, although clearly informative, can also be reductionist –excluding the emotionally salient features of competitors’ histories and forcing competitors together on a scalar metric, even when the competitors themselves do not see each other as comparable.
The results from sample-split models are important for social networking research, which has paid scant attention to the contextual conditions in which structural equivalence is most consequential for social action – especially hostile social actions.
The study suggests that new work will benefit from examining how demographic overlap, network stability, and perceived costs of conflict “activate” a structurally equivalent relationship to the point that it is not only salient but also conducive to conflict.
Professor Lee said, “Sociology mainly investigates the positive results of social success and collaboration. This study shows that any violent activities, including homicide, also have something to do with organizational and social structural equivalence.”
This study was co-led by Professor Matthew Bothner from ESMT in Germany, Professor Henning Piezunk from INSEAD in France, and Dr. Richard Haynes from the US Treasury and was featured at the PNAS (Proceedings of the National Academy of Sciences of the USA) in March.
(Figure: Drivers' competitive network and collisions. Nodes are drivers. Nodes enricled in black are labeled by name. Edges denote joint competition in at least one race. Red edges connecting indicate that the two drivers collided at least once. Using Fruchtermna-Reingold, nodes are generally proximte to the extendt that their average structural equivalence (over all races, from 1970 to 2014) is high.)
2018.04.24 View 7327