{"73311":{"#nid":"73311","#data":{"type":"news","title":"Study Identifies Mechanisms Cells Use to Remove Bits of RNA from DNA Strands","body":[{"value":"\u003Cp\u003EWhen RNA component units called ribonucleotides become embedded in genomic DNA, which contains the complete genetic data for an organism, they can cause problems for cells. It is known that ribonucleotides in DNA can potentially distort the DNA double helix, resulting in genomic instability and altered DNA metabolism, but not much is known about the fate of these ribonucleotides.\u003C\/p\u003E\n\u003Cp\u003EA new study provides a mechanistic explanation of how ribonucleotides embedded in genomic DNA are recognized and removed from cells. Two mechanisms, enzymes called ribonucleases (RNases) H and the DNA mismatch repair system, appear to interplay to root out the RNA components.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We believe this is the first study to show that cells utilize independent repair pathways to remove mispaired ribonucleotides embedded in chromosomal DNA, which can be sources of genetic modification if not removed,\u0022 said Francesca Storici, an assistant professor in the School of Biology at the Georgia Institute of Technology. \u0022The results also highlight a novel case of genetic redundancy, where the mismatch repair system and RNase H mechanisms compete with each other to remove misincorporated ribonucleotides and restore DNA integrity.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThe findings were reported Dec. 4, 2011 in the advance online publication of the journal \u003Cem\u003ENature Structural \u0026amp; Molecular Biology\u003C\/em\u003E. The research was supported by the Georgia Cancer Coalition, National Science Foundation and Georgia Tech Integrative BioSystems Institute.\n\u003C\/p\u003E\n\u003Cp\u003EStorici and Georgia Tech biology graduate students Ying Shen and Kyung Duk Koh conducted the study in collaboration with Bernard Weiss, a professor emeritus in the Department of Pathology and Laboratory Medicine at Emory University.\u003C\/p\u003E\n\u003Cp\u003E\u0022We wanted to understand how cells of the bacterium \u003Cem\u003EEscherichia coli\u003C\/em\u003E and the yeast \u003Cem\u003ESaccharomyces cerevisiae\u003C\/em\u003E tolerate the presence of different ribonucleotides embedded in their genomic DNA. We found that the structure of a ribonucleotide tract embedded in DNA influenced its ability to cause genetic mutations more than the tract\u0027s length,\u0022 said Storici.\n\u003C\/p\u003E\n\u003Cp\u003EWith double-stranded DNA, when wrong bases are paired or one or few nucleotides are in excess or missing on one of the strands, a mismatch is generated. If mismatches are not corrected, they can lead to mutations.\n\u003C\/p\u003E\n\u003Cp\u003EThe researchers found that single mismatched ribonucleotides in chromosomal DNA were removed by either the mismatch repair system or RNase H type 2. Mismatched ribonucleotides in the middle of at least four other ribonucleotides required RNase H type 1 for removal.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We were excited to find that a DNA repair mechanism like mismatch repair was activated by RNA\/DNA mismatches and could remove ribonucleotides embedded in chromosomal DNA,\u0022 explained Storici. \u0022In future studies, we plan to test whether other DNA repair mechanisms, such as nucleotide-excision repair and base-excision repair, can also locate and remove ribonucleotides in DNA.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EUsing gene correction assays driven by short nucleic acid polymers called oligonucleotides, the researchers showed that when ribonucleotides embedded in DNA were not removed, they served as templates for DNA synthesis and produced a mutation in the DNA. If both the mismatch repair system and RNase H repair mechanisms are disabled, ribonucleotide-driven gene modification increased by a factor of 47 in the yeast and 77,000 in the bacterium. \n\u003C\/p\u003E\n\u003Cp\u003EDefects in the mismatch repair system are known to predispose a person to certain types of cancer. Because the mismatch repair system is conserved from unicellular to multicellular organisms, such as humans, this study\u0027s findings open up the possibility that defects in the mismatch repair system could have consequences more critical than previously thought given the newly identified function of mismatch repair to target RNA\/DNA mispairs. \n\u003C\/p\u003E\n\u003Cp\u003EThe results also provide new information on the capacity of RNA to play an active role in DNA editing and remodeling, which could be the basis of an unexplored process of RNA-driven DNA evolution. \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cem\u003EThis project was supported by the National Science Foundation (NSF) (Award No. MCB-1021763). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of the NSF.\u003C\/em\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E Abby Robinson (abby@innovate.gatech.edu; 404-385-3364) or John Toon (jtoon@gatech.edu; 404-894-6986)\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Abby Robinson\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EWhen RNA ribonucleotides become embedded in genomic DNA, they can cause problems for cells, but not much is known about the fate of these ribonucleotides. A new study identifies two mechanisms cells use to recognize and remove ribonucleotides from DNA.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Study identifies two mechanisms cells use to remove RNA from DNA."}],"uid":"27206","created_gmt":"2011-12-04 01:00:00","changed_gmt":"2016-10-08 03:10:42","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-12-04T00:00:00-05:00","iso_date":"2011-12-04T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"73312":{"id":"73312","type":"image","title":"Ying Shen, Francesca Storici \u0026 Kyung Duk Koh","body":null,"created":"1449178002","gmt_created":"2015-12-03 21:26:42","changed":"1475894676","gmt_changed":"2016-10-08 02:44:36"},"73313":{"id":"73313","type":"image","title":"Ying Shen \u0026 Francesca Storici","body":null,"created":"1449178002","gmt_created":"2015-12-03 21:26:42","changed":"1475894676","gmt_changed":"2016-10-08 02:44:36"},"73314":{"id":"73314","type":"image","title":"Ying Shen, Francesca Storici \u0026 Kyung Duk Koh","body":null,"created":"1449178002","gmt_created":"2015-12-03 21:26:42","changed":"1475894676","gmt_changed":"2016-10-08 02:44:36"}},"media_ids":["73312","73313","73314"],"related_links":[{"url":"http:\/\/www.biology.gatech.edu\/","title":"School of Biology"},{"url":"http:\/\/www.biology.gatech.edu\/people\/index.php?id=francesca-storici","title":"Francesca Storici"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"146","name":"Life Sciences and Biology"}],"keywords":[{"id":"4896","name":"College of Sciences"},{"id":"1041","name":"dna"},{"id":"13560","name":"Francesca Storici"},{"id":"15258","name":"oligonucleotides"},{"id":"15259","name":"ribonucleotides"},{"id":"984","name":"RNA"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAbby Robinson\u003C\/strong\u003E\u003Cbr \/\u003EResearch News and Publications\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=avogel6\u0022\u003EContact Abby Robinson\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-385-3364\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["abby@innovate.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"73280":{"#nid":"73280","#data":{"type":"news","title":"MRS Medal Awarded to Zhong Lin Wang for Zinc Oxide Nanostructures","body":[{"value":"\u003Cp\u003ESearching the Web for \u0022zinc oxide nanostructures\u0022 produces thousands of hits -- most of them associated with the name of one scientist: Zhong Lin Wang, a Regent\u0027s professor at the Georgia Institute of Technology. Wang, a physicist who joined Georgia Tech in 1995, has almost single handedly launched a new field of research that takes advantage of the unique properties of zinc oxide nanostructures.\u003C\/p\u003E\n\u003Cp\u003EWang is perhaps best known for nanogenerators that harvest mechanical energy from the environment, taking advantage of the piezoelectric properties of zinc oxide nanowires to produce electrical current. Starting with output that could barely be measured in 2006, his research team has steadily improved the devices until today arrays of connected nanogenerators can produce as much as 30 volts.\n\u003C\/p\u003E\n\u003Cp\u003EMore recently, he has used the piezoelectric properties of the nanostructures to control charge transport in electronic devices, a technology known as piezotronics, which provides an alternative to traditional CMOS technology.  He has also coined the term \u0022piezo-phototronics\u0022 to describe techniques for controlling electro-optical processes in devices such as light-emitting diodes.\n\u003C\/p\u003E\n\u003Cp\u003EBy leaving a gap in the PowerPoint slide he uses to describe his family of zinc oxide nanostructures, Wang suggests there\u0027s more ahead.\n\u003C\/p\u003E\n\u003Cp\u003EWang received a 2011 Materials Research Society Medal Nov. 30th at the organization\u0027s fall meeting in Boston. The medal\u0027s commendation notes his \u0022seminal contributions in the discovery, controlled synthesis, and fundamental understanding of zinc oxide nanowires and nanobelts, and the design and fabrication of novel, nanowire-based nanosensors, piezotronic devices and nanogenerators for energy harvesting.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EWang joined Georgia Tech in 1995, after earning his Ph.D. at Arizona State University and working for Oak Ridge National Laboratory and the National Institute of Standards and Technology (NIST).  His first interest was electron microscopy, where he helped other Georgia Tech researchers see the world of the very small.  \n\u003C\/p\u003E\n\u003Cp\u003EHe got his first major international attention from research on carbon nanotubes -- tiny structures of interlocked carbon atoms that helped create a new research area in the mid-1990s.  Collaboration with Georgia Tech physicist Walt de Heer -- now known for his work with epitaxial graphene -- produced a 1996 paper on nanotube properties that included a microscope image of a carbon particle on the end of a nanotube.  Analyzing the nanotube\u0027s vibration allowed the researchers to determine the approximate mass of the particle, and their device become known worldwide as a \u0022nanobalance.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBut Wang soon realized that the popularity of carbon nanotubes made that research field a crowded one. In search of a research area with more opportunity, he returned to his undergraduate roots in oxide materials -- zinc oxide in particular.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Zinc oxide has a lot of advantages because of its semiconducting, piezoelectric, optical and other properties for sensors, transducers, energy applications and other uses,\u0022 he noted. \u0022I wanted to have a material that I could develop, to study the material in great detail, and to own the key intellectual property.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EHe began work on the material in 1999 and quickly produced significant results, including the development of \u0022nanobelts\u0022 reported in the journal \u003Cem\u003EScience\u003C\/em\u003E in 2001.  Details of the structures and their synthesis attracted other researchers, and the paper has now been cited more than 3,500 times.\n\u003C\/p\u003E\n\u003Cp\u003EThe nanobelt paper was followed by years of work investigating the properties and synthesis of zinc oxide structures.  Perhaps the most significant advance was the ability to grow aligned arrays of zinc oxide nanowires, knowledge that led directly to the development of nanogenerators.  Reported in April 2006 in the journal \u003Cem\u003EScience\u003C\/em\u003E, nanogenerators drew international attention to Georgia Tech and rapidly led to a series of improvements that opened up new ways of powering nanometer-scale devices for building self-powered nanotechnology. The generators now produce enough power to operate conventional electronic components such as LED displays.\n\u003C\/p\u003E\n\u003Cp\u003EIn the last few years, Wang has branched out into new forms of electronic devices, including piezotronic logic gates and memory, as well as light-emitting diodes enhanced with the piezo-phototronic effect.  Multiple devices have been combined into self-powered sensing systems that not only detect harmful materials, but also alert authorities wirelessly. He has also built systems that combine different kinds of power harvesting, such as nanogenerators and photovoltaic cells -- and developed a hybrid cell for the first time.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022When nobody else is paying attention to a technology area, that is when you can be a pioneer,\u0022 he said. \u0022By the time most people have begun to pay attention to it, you have already made significant progress.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EIn his 16-year career at Georgia Tech, Wang has produced 28 patent applications, along with another dozen invention disclosures.  He has formed a startup company to commercialize the technology, and published more than 20 articles in \u003Cem\u003EScience\u003C\/em\u003E and high-profile \u003Cem\u003ENature\u003C\/em\u003E journals.  Overall, he estimates his research team has produced more than 700 publications that have been cited 45,000 times with an h index of 103.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022When we began this work, we could see only dots -- no picture,\u0022 he added.  \u0022Today we are able to see the big picture of what can be done with these nanostructures.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EThough the MRS Medal recognizes Wang\u0027s research accomplishments, he\u0027s also proud of his role as teacher and mentor to students -- hundreds of them since 1995. Wang leads a large research group composed of post-doctoral fellows, graduate students and undergraduate students.  From his laboratory have come seven graduates who now hold assistant professor positions at prestigious U.S. institutions -- and more than 50 working at universities in China or Taiwan.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022As a professor, I view my job as having two parts: being an outstanding scientist and an outstanding educator,\u0022 he said. \u0022Our most important products are the students.  If they can go on to be faculty members at the most prestigious universities in the world, we have done our job.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ERegents\u0027 professor Zhong Lin Wang has received a 2011 Materials Research Society Medal for his contributions in the discovery, controlled synthesis, and fundamental understanding of zinc oxide nanowires and nanobelts.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Regents\u0027 professor Zhong Lin Wang has received an MRS Medal."}],"uid":"27303","created_gmt":"2011-12-01 01:00:00","changed_gmt":"2016-10-08 03:10:42","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-12-01T00:00:00-05:00","iso_date":"2011-12-01T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"73282":{"id":"73282","type":"image","title":"Zhong Lin Wang","body":null,"created":"1449177990","gmt_created":"2015-12-03 21:26:30","changed":"1475894676","gmt_changed":"2016-10-08 02:44:36"},"73283":{"id":"73283","type":"image","title":"Zhong Lin Wang","body":null,"created":"1449177990","gmt_created":"2015-12-03 21:26:30","changed":"1475894676","gmt_changed":"2016-10-08 02:44:36"},"73281":{"id":"73281","type":"image","title":"Zhong Lin Wang","body":null,"created":"1449177990","gmt_created":"2015-12-03 21:26:30","changed":"1475894676","gmt_changed":"2016-10-08 02:44:36"}},"media_ids":["73282","73283","73281"],"related_links":[{"url":"http:\/\/www.mrs.org\/f11-symposium-x\/","title":"MRS Fall Meeting"},{"url":"http:\/\/www.mse.gatech.edu\/","title":"Georgia Tech School of Materials Science and Engineering"},{"url":"http:\/\/www.mse.gatech.edu\/faculty-staff\/faculty\/zhong-lin-wang","title":"Zhong Lin Wang"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[],"keywords":[],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"72646":{"#nid":"72646","#data":{"type":"news","title":"Systems Engineering Helps Improve Flow of Visitors in Georgia Aquarium\u2019s New Dolphin Exhibit","body":[{"value":"\u003Cp\u003EMore than 1,800 visitors can move smoothly through the Georgia Aquarium\u0027s new AT\u0026amp;T Dolphin Tales exhibit, entering and leaving through the same set of doors. Their experience is not by accident though -- before the exhibit opened, logistics experts at the Georgia Institute of Technology carefully studied how guests would move and recommended ways to improve their experiences while minimizing congestion.\u003C\/p\u003E\n\u003Cp\u003E\u0022We offered Georgia Aquarium leaders accurate predictions on how the new AT\u0026amp;T Dolphin Tales exhibit would impact guest flow within the aquarium and how to optimize the operations logistics, efficiency and show schedules for the new exhibit,\u0022 said Eva K. Lee, a professor in the H. Milton Stewart School of Industrial and Systems Engineering at Georgia Tech.\n\u003C\/p\u003E\n\u003Cp\u003EThe new 84,000-square-foot AT\u0026amp;T Dolphin Tales attraction, which opened in April 2011, includes a theater with performances of Atlantic Bottlenose dolphins in a Broadway-style production with live actors and trainers, all set to an orchestral soundtrack. The exhibit also features a lobby area where visitors can be face-to-face with the dolphins through a 25-foot viewing window.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We knew that managing the flow of guests through the new AT\u0026amp;T Dolphin Tales exhibit was going to be more difficult than the other aquarium galleries because guests would be entering and exiting the exhibit through the same space,\u0022 said Brian Davis, director of education and guest programs at the Georgia Aquarium. \u0022The logistical predictions and recommendations Georgia Tech provided us were extremely accurate and enabled us to ensure an amazing guest experience while remaining fiscally responsible.\u0022\n\u003C\/p\u003E\n\u003Cp\u003ETo provide recommendations to the Georgia Aquarium on how to optimize visitor flow through the new exhibit, Lee and Georgia Tech graduate student Chien-Hung Chen created RealOpt-ABM, a large-scale modeling and decision support software suite that could model guest movement through the entire aquarium. \u003C\/p\u003E\n\u003Cp\u003EWith this software, the researchers predicted guest flow through the new exhibit and the impact of the new exhibit to surrounding areas and overall visitor flow. They were also able to determine the best strategies for show scheduling, resource allocation, space usage, and theater loading and unloading. RealOpt-ABM produced recommendations that were implemented for operations design of the new exhibit, according to Joe Handy, vice president of guest experience at the Georgia Aquarium.\n\u003C\/p\u003E\n\u003Cp\u003EAccording to Lee, the software\u0027s success lies in its integrated simulation and optimization approach and its inclusion of human cognitive and behavioral elements. The software\u0027s computational speed also allowed for rapid solution strategies and on-the-fly reconfigurations. Facility layout, physical design and activities at specific points of interest were captured in sub-models, which were aggregated and coupled to form the overall model. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022RealOpt-ABM incorporated advances in agent-based simulation that capture the stochastic nature of the events within the aquarium, optimization of resource allocation and show schedules, and modeling of human cognitive decisions that affect show preference and guest behavior,\u0022 explained Lee.\n\u003C\/p\u003E\n\u003Cp\u003ETo validate the model, Lee, research engineer Niquelle Brown and 10 Georgia Tech students analyzed guest flow and behavior patterns in the entire aquarium before the new exhibit opened. Through time-motion studies in 2010, they collected guest flow data and captured the decisions guests made, such as turning left or right when they arrived at an intersection and how long guests spent in each exhibit area. The data showed that guest movement changed based on the time of day and what time guests arrived at the museum.\u003C\/p\u003E\n\u003Cp\u003EUsing RealOpt-ABM, the researchers accurately predicted the amount of time required to load and unload the AT\u0026amp;T Dolphin Tales theater, depending on the number of guests, which led to a recommendation that performances be separated by at least 90 minutes to minimize congestion. The researchers also recommended that on days with fewer than 6,000 aquarium attendees, only two shows should be offered. This recommendation was based on the need to maintain the comfort and health of the dolphins while minimizing unnecessary operations costs. \n\u003C\/p\u003E\n\u003Cp\u003ERealOpt-ABM also detailed the optimal number and location of ticket scanners and traffic controllers and the best time to open the theatre doors so that the waiting time and queue length were acceptable. The study also predicted that unless other provisions were made, a large percentage of the new exhibit\u0027s lobby area would be occupied by baby strollers that were not allowed in the theater. Lee\u0027s team recommended the creation of valet stroller parking in the main lobby of the aquarium to avoid logistics bottlenecks and congestion in the exhibit lobby area.\n\u003C\/p\u003E\n\u003Cp\u003EThis logistics research project is one of six finalists for the 2011 Daniel H. Wagner Prize for Excellence in Operations Research Practice, which is given by the Institute for Operations Research and the Management Sciences (INFORMS). The winner will be selected on Nov. 14 at the INFORMS Annual Meeting, following presentations by the finalists.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Effective strategies for managing guest flow are imperative for the successful operation of the aquarium and we trust Georgia Tech\u0027s logistics advice 100 percent,\u0022 said Davis. \u0022As the Georgia Aquarium continues to grow and expand, we will always look to Georgia Tech\u0027s expertise to maximize the experience for our guests.\u0022\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\u003C\/strong\u003E\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts:\u003C\/strong\u003E Abby Robinson (abby@innovate.gatech.edu; 404-385-3364) or John Toon (jtoon@gatech.edu; 404-894-6986)\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Abby Robinson\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ESystems engineers at Georgia Tech offered the Georgia Aquarium accurate predictions on how its new AT\u0026amp;T Dolphin Tales exhibit would impact aquarium guest flow and how to optimize the operations logistics, efficiency and show schedules for the exhibit.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Guests can flow smoothly through new AT\u0026T Dolphin Tales exhibit."}],"uid":"27206","created_gmt":"2011-11-14 01:00:00","changed_gmt":"2016-10-08 03:10:38","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-11-14T00:00:00-05:00","iso_date":"2011-11-14T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"72647":{"id":"72647","type":"image","title":"Georgia Aquarium dolphin show","body":null,"created":"1449177942","gmt_created":"2015-12-03 21:25:42","changed":"1475894661","gmt_changed":"2016-10-08 02:44:21"},"72648":{"id":"72648","type":"image","title":"Eva Lee","body":null,"created":"1449177942","gmt_created":"2015-12-03 21:25:42","changed":"1475894661","gmt_changed":"2016-10-08 02:44:21"},"72649":{"id":"72649","type":"image","title":"AT\u0026T Dolphin Tales theater","body":null,"created":"1449177942","gmt_created":"2015-12-03 21:25:42","changed":"1475894661","gmt_changed":"2016-10-08 02:44:21"}},"media_ids":["72647","72648","72649"],"related_links":[{"url":"http:\/\/www.informs.org\/Recognize-Excellence\/Community-Prizes-and-Awards\/CPMS\/The-Daniel-H.-Wagner-Prize-for-Excellence-in-Operations-Research-Practice","title":"2011 Daniel H. Wagner Prize for Excellence in Operations Research Practice"},{"url":"http:\/\/www.isye.gatech.edu\/faculty-staff\/profile.php?entry=el44","title":"Eva Lee"},{"url":"http:\/\/www.isye.gatech.edu\/","title":"Stewart School of Industrial and Systems Engineering"},{"url":"http:\/\/www.georgiaaquarium.org\/","title":"Georgia Aquarium"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"135","name":"Research"}],"keywords":[],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAbby Robinson\u003C\/strong\u003E\u003Cbr \/\u003EResearch News and Publications\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=avogel6\u0022\u003EContact Abby Robinson\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-385-3364\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["abby@innovate.gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"72427":{"#nid":"72427","#data":{"type":"news","title":"Study Compares Fundamental Techniques for Doping Graphene Sheets","body":[{"value":"\u003Cp\u003ENanotechnology researchers at the Georgia Institute of Technology have conducted the first direct comparison of two fundamental techniques that could be used for chemically doping sheets of two-dimensional graphene for the fabrication of devices and interconnects.\u003C\/p\u003E\n\u003Cp\u003EChemical doping is routinely used in conventional three-dimensional semiconductors to control the density of electron carriers that are essential to the operation of devices such as transistors.  But graphene, a semi-metal available in sheets just one atom thick, has properties very different from traditional materials such as silicon -- though researchers say doping will still be needed for producing electronic devices.\n\u003C\/p\u003E\n\u003Cp\u003EThe bad news is that electronic designers working with graphene won\u0027t be able to simply apply what they\u0027ve been doing with three-dimensional semiconductors -- which would translate to vastly degraded material quality for graphene.  The good news, according to the study, is that graphene doping can be combined with other processes -- and need be applied only to the edges of nanoscale structures being fabricated.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We are learning how to manipulate these two-dimensional sheets of carbon atoms to get some very unusual results that aren\u0027t available with any other material,\u0022 said James Meindl, director of Georgia Tech\u0027s Nanotechnology Research Center, where the research was conducted.  \u0022Doping graphene to try to influence its properties is important to being able to use it effectively.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EDetails of the research were published online in the journal \u003Cem\u003ECarbon\u003C\/em\u003E on October 29th. The research was supported by the Semiconductor Research Corporation (SRC), the Defense Advanced Research Projects Agency (DARPA) through the Interconnect Focus Center, and the National Science Foundation (NSF).\n\u003C\/p\u003E\n\u003Cp\u003EBecause graphene sheets contain so few atoms by area, the substitution of elements such as oxygen or nitrogen for carbon atoms in the lattice -- as in conventional doping -- detracts from the high electron mobility and other properties that make the material interesting.  So the researchers are rethinking the doping process to take advantage of graphene\u0027s unique properties.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022When we work with a three-dimensional semiconductor, we embed the dopant species in the bulk material and then fabricate it into a device,\u0022 said Kevin Brenner, a graduate research assistant in the Georgia Tech School of Electrical and Computer Engineering.  \u0022With graphene, we will dope the material as we process it and fabricate it into devices or interconnects. Doping may be done as part of other fabrication steps such as plasma etching, and that will require us to reinvent the whole process.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EUsing sheets of exfoliated graphene, Brenner and collaborators Raghu Murali and Yinxiao Yang evaluated the effectiveness of two different techniques: edge passivation by coupling electron-beam lithography with a common resist material, and adsorption from coating the surface of the material.  They found that the edge treatment, which chemically reacts with defects created when the material is cut, was a thousand times more efficient at producing carriers in the graphene sheets than the surface treatment.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We will only be working with the edges of the material,\u0022 Brenner explained.  \u0022That will allow us to leave the center pristine and free of defects.  Using this approach, we can maintain very high mobilities and the special properties of graphene while creating very high carrier densities.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBecause of the two-dimensional nature of the graphene, controlling the edge chemistry can provide control over the bulk properties of the sheet.  \u0022At nanoscale dimensions, the edge atoms tend to dominate over surface adsorption techniques,\u0022 he added.   \u0022With a seven nanometer by seven nanometer graphene device, passivating just one edge C-atom provides the doping equivalent of covering the entire surface.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EFor doping the edge of a graphene structure, the team applied a thin film of hydrogen silsesquioxane (HSQ), a chemical normally used as a resist for etching, then used electron beam lithography to cross-link the material, which added oxygen atoms to the edges to create p-type doping.  The resist and electron beam system combined to provide nanometer-scale control over where the chemical changes took place.\n\u003C\/p\u003E\n\u003Cp\u003EDoping treatment could also be applied using plasma etching, Brenner said.  Controlling the specific atoms used in the plasma, or conducting the etching process in an environment containing specific atoms, could drive those atoms into the edges where they would serve as dopants.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Anytime you create an edge, you have created a location where you can passivate using a dopant,\u0022 he added.  \u0022Instead of needing to embed it in the surface, you can just take the edge that is already there and passivate it with oxygen, nitrogen, hydrogen or other dopant.  It could be almost an effortless process because the doping can be done as part of another step.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EBeyond fabricating electronic devices, Nanotechnology Research Center scientists are interested in using graphene for interconnects, potentially as a replacement for copper.  As interconnect structures become smaller and smaller, the resistivity of copper increases.  Edge-doped graphene sheets exhibit a trend of increasing doping with reduced dimensions, possibly becoming more conductive as their size shrinks below 50 nanometers, making them attractive for nanoscale interconnects.\n\u003C\/p\u003E\n\u003Cp\u003EArmed with basic information about graphene doping, the researchers hope to now begin producing devices to study how graphene actually performs.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022Now that we have made a start at understanding how to dope the material, the next step is to begin putting this into nanoscale devices,\u0022 Brenner said.  \u0022We want to see what kind of performance we can get.  That may tell us where graphene\u0027s niche could be as an electronic material.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EMeindl, who has worked with silicon since the dawn of integrated circuits, says it\u0027s too early to predict where graphene will ultimately find commercial applications.  But he says the material\u0027s properties are too interesting not to explore.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022The chances are that something very interesting and unique will develop from the use of graphene,\u0022 he said.  \u0022But we don\u0027t yet have the ability to predict what we will be able to do with this new material.\u0022  \n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\nGeorgia Institute of Technology\u003Cbr \/\u003E\n75 Fifth Street, N.W., Suite 314\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003E\n\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EMedia Relations Contacts\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E) or Abby Robinson (404-385-3364)(\u003Ca href=\u0022mailto:abby@innovate.gatech.edu\u0022\u003Eabby@innovate.gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ENanotechnology researchers have conducted the first direct comparison of two fundamental techniques that could be used for chemically doping sheets of two-dimensional graphene for the fabrication of devices and interconnects.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Study examines key process for graphene devices \u0026 interconnects."}],"uid":"27303","created_gmt":"2011-11-05 00:00:00","changed_gmt":"2016-10-08 03:10:38","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-11-07T00:00:00-05:00","iso_date":"2011-11-07T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"72428":{"id":"72428","type":"image","title":"Studying graphene doping","body":null,"created":"1449177930","gmt_created":"2015-12-03 21:25:30","changed":"1475894656","gmt_changed":"2016-10-08 02:44:16"},"72429":{"id":"72429","type":"image","title":"SEM image of doping study","body":null,"created":"1449177930","gmt_created":"2015-12-03 21:25:30","changed":"1475894656","gmt_changed":"2016-10-08 02:44:16"},"72430":{"id":"72430","type":"image","title":"Studying graphene doping","body":null,"created":"1449177930","gmt_created":"2015-12-03 21:25:30","changed":"1475894656","gmt_changed":"2016-10-08 02:44:16"}},"media_ids":["72428","72429","72430"],"related_links":[{"url":"http:\/\/www.nrc.gatech.edu\/","title":"Nanotechnology Research Center"},{"url":"http:\/\/www.ece.gatech.edu\/","title":"School of Electrical and Computer Engineering"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"149","name":"Nanotechnology and Nanoscience"},{"id":"135","name":"Research"}],"keywords":[{"id":"1928","name":"devices"},{"id":"8458","name":"doping"},{"id":"429","name":"graphene"},{"id":"430","name":"interconnects"},{"id":"2783","name":"James Meindl"},{"id":"107","name":"Nanotechnology"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EJohn Toon\u003C\/strong\u003E\u003Cbr \/\u003EResearch News \u0026amp; Publications Office\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=jt7\u0022\u003EContact John Toon\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-6986\u003C\/strong\u003E\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}},"107761":{"#nid":"107761","#data":{"type":"event","title":"Visual Representation of Data: Developing Effective Graphs \u0026 Charts","body":[{"value":"\u003Cp\u003EThis session will examine various variable types and the best way to visually represent those types.\u0026nbsp; The Tecplot data visualization package (free to GT students) will be introduced.\u0026nbsp; \u003C\/p\u003E\u003Cp\u003EJoin us for this hands-on training on effective ways to visually present your data for articles, poster sessions and more.\u003Cbr \/\u003ESpace is first come, first served, but priority is given to those who have registered.\u003Cbr \/\u003E\u003Ca title=\u0022http:\/\/gradcommcert.gatech.edu\/login\/reg.php\u0022 href=\u0022http:\/\/gradcommcert.gatech.edu\/login\/reg.php\u0022\u003ERegister Now\u003C\/a\u003E\u003Cbr \/\u003E\u003C\/p\u003E\u003Cp\u003EPlease contact\u0026nbsp;\u003Ca href=\u0022http:\/\/www.library.gatech.edu\/about\/email_form.php?type=user\u0026amp;id=281\u0026amp;return=staff_directory\u0022\u003EChris Doty\u003C\/a\u003E\u0026nbsp;(Phone: 404-894-4536) if you need additional information.\u003C\/p\u003E\u003Cp\u003EPart of the G.L.U.E. (\u0027Graduate Library User Education\u0027) Workshop Series\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EThis session will examine various variable types and the best way to visually represent those types.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"This session will examine various variable types and the best way to visually represent those types."}],"uid":"27508","created_gmt":"2012-02-08 15:57:45","changed_gmt":"2016-10-08 01:57:56","author":"Tearanny Street","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2012-02-22T10:00:00-05:00","event_time_end":"2012-02-22T11:30:00-05:00","event_time_end_last":"2012-02-22T11:30:00-05:00","gmt_time_start":"2012-02-22 15:00:00","gmt_time_end":"2012-02-22 16:30:00","gmt_time_end_last":"2012-02-22 16:30:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"groups":[{"id":"47240","name":"Georgia Tech Library"}],"categories":[],"keywords":[{"id":"11211","name":"library_classes"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1791","name":"Student sponsored"}],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EChris Doty\u003C\/p\u003E\u003Cp\u003EGeorgia Tech Library\u003C\/p\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}