{"71455":{"#nid":"71455","#data":{"type":"news","title":"New Decontamination System Kills Anthrax Rapidly","body":[{"value":"\u003Cp\u003EIn October 2001, letters containing anthrax spores were mailed to several news media offices and two U.S. senators, killing five people and infecting 17 others. Clearing the Senate office building of the spores with chlorine dioxide gas cost $27 million, according to the Government Accountability Office. Cleaning the Brentwood postal facility outside Washington cost $130 million and took 26 months. \u003C\/p\u003E\n\u003Cp\u003EResearchers at the Georgia Tech Research Institute (GTRI) in collaboration with Austin-based Stellar Micro Devices, Inc. (SMD) have developed prototypes of a rapid, non-disruptive and less expensive method that could be used to decontaminate bioterrorism hazards in the future.\n\u003C\/p\u003E\n\u003Cp\u003EUsing flat panel modules that produce X-rays and ultraviolet-C (UV-C) light simultaneously, the researchers can kill anthrax spores in two to three hours without any lingering effects. The system also has the ability to kill anthrax spores hidden in places like computer keyboards without causing damage. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022This is certainly an improvement over previous techniques,\u0022 said Brent Wagner, GTRI principal research scientist and director of its Phosphor Technology Center of Excellence (PTCOE). \u0022The UV-C attacks spores on surfaces and the X-rays penetrate through materials and kill spores in cracks and crevices.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EX-ray irradiation is used commercially to sterilize medical products and food by disrupting the ability of a microorganism to reproduce. UV-C also prevents replication, but both types of radiation can penetrate the outer structure of an anthrax spore to destroy the bacteria inside.\n\u003C\/p\u003E\n\u003Cp\u003EThe current decontamination standard - chlorine dioxide gas - kills microorganisms by disrupting transport of nutrients across the cell wall, but cannot reach hidden spores. Hard surfaces must be cleaned independently with harsh liquid chlorine dioxide. In addition, people cannot re-enter a room fumigated with chlorine dioxide until the gas is neutralized with sodium bisulfite vapor and vented from the building.\n\u003C\/p\u003E\n\u003Cp\u003EThe new decontamination system resembles a coat rack with radiation modules arranged on rings at various heights that face outward to broadcast radiation throughout a room. Since the X-rays and UV-C are lethal at the flux densities used, the system operates unattended and is turned on outside the affected space.\n\u003C\/p\u003E\n\u003Cp\u003EUV-C light in the modules is produced using the optical and electrical phenomenon of cathodoluminescence. Numerous electron beams are generated by arrays of cold cathodes, each acting like the electron gun in a cathode ray tube.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022When an electron beam hits a powder phosphor, it luminesces and emits visible and\/or non-visible light,\u0022 explained Hisham Menkara, a GTRI senior research scientist.\n\u003C\/p\u003E\n\u003Cp\u003EGTRI became involved in SMD\u0027s project, which was funded by the Air Force Research Laboratory\u0027s Small Business Innovation Research program, because the PTCOE housed UV-C phosphors created and patented by Sarnoff Corporation in the mid-1970s.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We knew that Georgia Tech had experts in powder phosphors with regard to flat panel displays and we approached them to develop new phosphors for our decontamination purpose,\u0022 said Mark Eaton, president and CEO of SMD. \u0022We were fortunate that they had UV-C phosphors available from decades earlier.\u0022\n\u003C\/p\u003E\n\u003Cp\u003EWith the Sarnoff phosphors in hand, Wagner and Menkara set off to determine the best UV-C emitting phosphor and optimize its properties for use with X-rays in SMD\u0027s small flat panel display.\n\u003C\/p\u003E\n\u003Cp\u003ETo find the best phosphor that emitted light in the UV-C region of the spectrum - wavelengths below 280 nanometers - the emission spectra of each phosphor was measured against the DNA absorption curve. This curve shows the optimal wavelengths to destroy an organism\u0027s DNA. \n\u003C\/p\u003E\n\u003Cp\u003EAfter investigating many different phosphors, the researchers chose lanthanum phosphate:praseodymium (LaPO4:Pr or LAP:Pr) as the most efficient phosphor, with a power efficiency near 10 percent. Since the UV emission didn\u0027t fall completely under the DNA absorption curve, the relative \u0027killing efficiency\u0027 was approximately 50 percent. \n\u003C\/p\u003E\n\u003Cp\u003EIn the laboratory, Menkara created the phosphor by mixing precursors lanthanum oxide, hydrogen phosphate and praseodymium fluoride (La2O3, H3PO4 and PrF3, respectively) in a glass beaker with methanol (CH3OH) and ammonium chloride (NH4Cl). Air drying the mixture in a fume hood caused the methanol to completely evaporate. \n\u003C\/p\u003E\n\u003Cp\u003EThe resultant cake was crushed into a fine powder, heated in a furnace to a temperature as high as 1250 degrees Celsius for two hours and crushed again.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022To determine the best conditions for producing the highest efficiency phosphor, we tried different precursors and completed the firing under different atmospheric conditions and temperatures,\u0022 explained Menkara.\n\u003C\/p\u003E\n\u003Cp\u003ETest results showed that higher temperatures were more efficient and a capped quartz tube was the best container to hold the powder inside the furnace. Wagner and Menkara also found that adding lithium fluoride (LiF) and reducing the praseodymium concentration increased the cathodoluminescent properties of the LAP:Pr phosphor.\n\u003C\/p\u003E\n\u003Cp\u003EWith the improved phosphor, laboratory tests conducted by SMD showed that the combined X-ray and UV-C decontamination system could kill anthrax spores. \n\u003C\/p\u003E\n\u003Cp\u003EGTRI researchers hope to develop new UV-C phosphors that can achieve cathodoluminescent efficiency higher than 10 percent with an emission spectrum that provides increased coverage of the DNA absorption curve.\n\u003C\/p\u003E\n\u003Cp\u003EWith increased efficiency, UV-C panels could be used for sterilizing medical equipment or purification applications.\n\u003C\/p\u003E\n\u003Cp\u003E\u0022We may be able to use UV-C panels to clean wastewater, which would be better than the lamps currently used. In the environment where the lamps must operate, they are very difficult to clean, whereas flat panels could be cleaned with a squeegee,\u0022 noted Eaton.\n\u003C\/p\u003E\n\u003Cp\u003EAnother potential application is to kill viruses in buildings used to house chickens. Current methods involve removing the chickens and raising the temperature in the chicken houses for several days to deactivate the virus. \n\u003C\/p\u003E\n\u003Cp\u003E\u0022With the combined UV-C\/X-ray system, you could turn the system on for a few hours, kill the viruses and as soon as you turn it off, the chickens could come right back in,\u0022 said Wagner.\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 100\u003Cbr \/\u003E\nAtlanta, Georgia  30308  USA\n\u003C\/strong\u003E\u003C\/p\u003E\n\u003Cp\u003EMedia Relations Contacts: Abby Vogel (404-385-3364); E-mail: (\u003Ca href=\u0022mailto:avogel@gatech.edu\u0022\u003Eavogel@gatech.edu\u003C\/a\u003E) or Kirk Englehardt (404-407-7280); E-mail: (\u003Ca href=\u0022mailto:kirk.englehardt@gtri.gatech.edu\u0022\u003Ekirk.englehardt@gtri.gatech.edu\u003C\/a\u003E) or John Toon (404-894-6986); E-mail: (\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E).\n\u003C\/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWriter:\u003C\/strong\u003E Abby Vogel\n\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Combination X-ray and ultraviolet-c system leaves no lingering effects"}],"field_summary":[{"value":"A rapid, non-disruptive and less expensive method to decontaminate bioterrorism hazards has been developed. Flat panels producing X-rays and ultraviolet-C light kill anthrax spores, even hidden ones, in two to three hours without lingering effects.","format":"limited_html"}],"field_summary_sentence":[{"value":"Anthrax decontamination system leaves no trace"}],"uid":"27206","created_gmt":"2008-01-29 01:00:00","changed_gmt":"2016-10-08 03:03:24","author":"Abby Vogel Robinson","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2008-01-29T00:00:00-05:00","iso_date":"2008-01-29T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"71456":{"id":"71456","type":"image","title":"Anthrax Decontamination","body":null,"created":"1449177376","gmt_created":"2015-12-03 21:16:16","changed":"1475894637","gmt_changed":"2016-10-08 02:43:57"},"71457":{"id":"71457","type":"image","title":"Anthrax decontamination2","body":null,"created":"1449177376","gmt_created":"2015-12-03 21:16:16","changed":"1475894637","gmt_changed":"2016-10-08 02:43:57"}},"media_ids":["71456","71457"],"related_links":[{"url":"http:\/\/gtri.gatech.edu\/","title":"Georgia Tech Research Institute"}],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"145","name":"Engineering"},{"id":"146","name":"Life Sciences and Biology"},{"id":"147","name":"Military Technology"},{"id":"135","name":"Research"}],"keywords":[{"id":"1132","name":"anthrax"},{"id":"1001","name":"bioterrorism"},{"id":"7503","name":"cathodoluminescence"},{"id":"7502","name":"chlorine dioxide"},{"id":"7500","name":"decontamination"},{"id":"7501","name":"phosphor"},{"id":"7505","name":"purify"},{"id":"170884","name":"sterilize"},{"id":"7329","name":"ultraviolet"},{"id":"1448","name":"x-ray"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\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","format":"limited_html"}],"email":["abby@innovate.gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}