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Searching for Resonances in the Unbound 6Be Nucleus by Using a Radioactive 7Be Beam
채경육,D. W. Bardayan,J. C. Blackmon,M. S. Smith,A. E. Champagne,J. J. Das,R. P. Fitzgerald,D. W. Visser,V. Guimaraes,K. L. Jones,S. D. Pain,J. S. Thomas,M. S. Johnson,R. L. Kozub,R. J. Livesay,Z. Ma,C. 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.11
Knowledge of the <sup>3</sup>He(<sup>3</sup>He,<sup>2</sup><i>p</i>)<sup>4</sup>He reaction is important for understanding stellar burning and solar neutrino production. Previous measurements have found a surprisingly large rise in the cross section at low energies that could be due to a low-energy resonance in the <sup>3</sup>He + <sup>3</sup>He (<sup>6</sup>Be) system or electron screening. In the <sup>6</sup>Be nucleus, however, no excited states have been observed above the first 2<sup>+</sup> state at <i>E<sub>x</sub></i> = 1.67 MeV up to 23 MeV, even though several are expected. The <sup>2</sup>H(<sup>7</sup>Be,<sup>3</sup>H)<sup>6</sup>Be reaction has been studied for the first time to search for resonances in the <sup>6</sup>Be nucleus that may affect our understanding of the <sup>3</sup>He(<sup>3</sup>He,<sup>2</sup><i>p,</i>)<sup>4</sup>He reaction. A 100-MeV radioactive <sup>7</sup>Be beam from the Holifield Radioactive Ion Beam Facility (HRIBF) was used to bombard CD<sub>2</sub> targets, and tritons were detected by using the silicon detector array (SIDAR). A combination of reaction mechanisms appears to be necessary to explain the observed triton energy spectrum.
Sharma, Virender K.,Johnson, Natalie,Cizmas, Leslie,McDonald, Thomas J.,Kim, Hyunook Elsevier 2016 CHEMOSPHERE - Vol.150 No.-
<P><B>Abstract</B></P> <P>Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) in the aquatic environment have become an emerging contaminant issue, which has implications for human and ecological health. This review begins with an introduction to the occurrence of ARB and ARG in different environmental systems such as natural environments and drinking water resources. For example, ARG or ARB with resistance to ciprofloxacin, sulfamethoxazole, trimethoprim, quinolone, vancomycin, or tetracycline (e.g., <I>tet</I>(A), <I>tet</I>(B), <I>tet</I>(C), <I>tet</I>(G)<I>, tet</I>(O)<I>, tet</I>(M)<I>, tet</I>(W), <I>sul</I> I, and <I>sul</I> II) have been detected in the environment. The development of resistance may be intrinsic, may be acquired through spontaneous mutations (<I>de novo</I>), or may occur due to horizontal gene transfer from donor bacteria, phages, or free DNA to recipient bacteria. An overview is also provided of the current knowledge regarding inactivation of ARB and ARG, and the mechanism of the effects of different disinfection processes in water and wastewater (chlorination, UV irradiation, Fenton reaction, ozonation, and photocatalytic oxidation). The effects of constructed wetlands and nanotechnology on ARB and ARG are also summarized.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Prevalence of ARB and ARG in rivers, lakes, surface water, wastewater, and sludge. </LI> <LI> Mechanism of resistance include horizontal gene transfer from donor bacteria. </LI> <LI> Chlorine and advanced oxidation processes inactivate ARB and ARG significantly. </LI> <LI> Flow pattern of the constructed wetlands governs removal of ARB and ARG. </LI> <LI> Nanoparticles have a role in investigating mechanism of transfer of ARG from genera. </LI> </UL> </P>
Daekyung Kim,Hyunwoo Kim,Thomas J. Johnson 한국언론학회 2011 Asian Communication Research Vol.8 No.S
This study explores the perceptual and behavioral components of third-person effect (TPE) hypothesis in the new environment of political communication during the 2006 local election in South Korea. Based on a Web-based survey of 227 Internet users, we examined self?other disparities in perceiving user-generated online political messages and if the self-other perceptual disparity leads to a willingness to endorse the government regulation on online political communications. This study found that online users tended to perceive greater influences of political messages on other people than on themselves. However, this study failed to find that third-person perception leads to support for censorship. Instead, this study found that negative effects of online political messages on self, rather than on others, significantly predicted support of the government regulation. Based on these results, the implications of the study and direction for the future study were discussed.
Report from IPITA-TTS Opinion Leaders Meeting on the Future of &bgr;-Cell Replacement
Bartlett, Stephen T.,Markmann, James F.,Johnson, Paul,Korsgren, Olle,Hering, Bernhard J.,Scharp, David,Kay, Thomas W. H.,Bromberg, Jonathan,Odorico, Jon S.,Weir, Gordon C.,Bridges, Nancy,Kandaswamy, R Wolters Kluwer Health, Inc. All rights reserved. 2016 Transplantation Vol.100 No.2
Lifestyle-dependent brain change: a longitudinal cohort MRI study
Kim, Regina EY.,Yun, Chang-Ho,Thomas, Robert J.,Oh, Jang-Hoon,Johnson, Hans J.,Kim, Soriul,Lee, Seungku,Seo, Hyung Suk,Shin, Chol Elsevier 2018 Neurobiology of aging Vol.69 No.-
<P><B>Abstract</B></P> <P>We investigated both independent and interconnected effects of 3 lifestyle factors on brain volume, measuring yearly changes using large-scale longitudinal magnetic resonance imaging, in middle-aged to older adults. We measured brain volumes in a cohort (<I>n</I> = 984, 49–79 years) from the Korean Genome and Epidemiology Study group, using baseline and follow-up estimates after 4 years. In our analysis, the accelerated brain atrophy in normal aging was observed across regions (e.g., brain tissue: -0.098 ± 0.01 mL/y, <I>p</I> < 0.001). An independent lifestyle-specific trend of brain atrophy across time was also evident in men, where smoking (<I>p</I> = 0.012) and physical activity (<I>p</I> = 0.014) showed the strongest association with the atrophy rate. Linear regression analysis of the interconnected effect revealed that brain atrophy is mitigated by intense physical activity in smoking males. Lifestyle factors did not show any significant effect on brain volume in women. These results provide important information regarding lifestyle factors that affect brain aging in mid-to-late adulthood. Our findings may aid in the identification of preventive measures against dementia.</P>
Executive Summary of IPITA-TTS Opinion Leaders Report on the Future of &bgr;-Cell Replacement
Markmann, James F.,Bartlett, Stephen T.,Johnson, Paul,Korsgren, Olle,Hering, Bernhard J.,Scharp, David,Kay, Thomas W. H.,Bromberg, Jonathan,Odorico, Jon S.,Weir, Gordon C.,Bridges, Nancy,Kandaswamy, R Williams & Wilkins Co 2016 Transplantation Vol.100 No.7
SUMMARY: The International Pancreas and Islet Transplant Association (IPITA), in conjunction with the Transplantation Society (TTS), convened a workshop to consider the future of pancreas and islet transplantation in the context of potential competing technologies that are under development, including the artificial pancreas, transplantation tolerance, xenotransplantation, encapsulation, stem cell derived beta cells, beta cell proliferation, and endogenous regeneration. Separate workgroups for each topic and then the collective group reviewed the state of the art, hurdles to application, and proposed research agenda for each therapy that would allow widespread application. Herein we present the executive summary of this workshop that focuses on obstacles to application and the research agenda to overcome them; the full length article with detailed background for each topic is published as an online supplement to Transplantation.
Kim, Kyung Hwan,Kim, Jeongho,Oang, Key Young,Lee, Jae Hyuk,Grolimund, Daniel,Milne, Christopher J.,Penfold, Thomas J.,Johnson, Steven L.,Galler, Andreas,Kim, Tae Wu,Kim, Jong Goo,Suh, Deokbeom,Moon, J The Royal Society of Chemistry 2015 Physical chemistry chemical physics Vol.17 No.36
<P>Identifying the intermediate species along a reaction pathway is a first step towards a complete understanding of the reaction mechanism, but often this task is not trivial. There has been a strong on-going debate: which of the three intermediates, the CHI<SUB>2</SUB> radical, the CHI<SUB>2</SUB>–I isomer, and the CHI<SUB>2</SUB><SUP>+</SUP> ion, is the dominant intermediate species formed in the photolysis of iodoform (CHI<SUB>3</SUB>)? Herein, by combining time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TR-XAS), we present strong evidence that the CHI<SUB>2</SUB> radical is dominantly formed from the photolysis of CHI<SUB>3</SUB> in methanol at 267 nm within the available time resolution of the techniques (∼20 ps for TRXL and ∼100 ps for TR-XAS). The TRXL measurement, conducted using the time-slicing scheme, detected no CHI<SUB>2</SUB>–I isomer within our signal-to-noise ratio, indicating that, if formed, the CHI<SUB>2</SUB>–I isomer must be a minor intermediate. The TR-XAS transient spectra measured at the iodine L<SUB>1</SUB> and L<SUB>3</SUB> edges support the same conclusion. The present work demonstrates that the application of these two complementary time-resolved X-ray methods to the same system can provide a detailed understanding of the reaction mechanism.</P> <P>Graphic Abstract</P><P>We identify a major transient species formed in the photolysis of CHI<SUB>3</SUB> by combining time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TR-XAS). <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5cp03686k'> </P>