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[PC-0012] Pre-study for early detection of Fusarium fujikuroi via fluorescence imaging method
Jaeyoung Kim(Jaeyoung Kim),Younguk Kim(Younguk Kim),Hyeonso Ji(Hyeonso Ji),Songlim Kim(Songlim Kim),Hyoja Oh(Hyoja Oh),Youngjun Mo(Youngjun Mo),Kyunghwan Kim(Kyunghwan Kim),Jeongho Baek(Jeongho Baek) 한국육종학회 2022 한국육종학회 공동학술발표집 Vol.2022 No.-
Structural Dynamics of 1,2-Diiodoethane in Cyclohexane Probed by Picosecond X-ray Liquidography
Kim, Jeongho,Lee, Jae Hyuk,Kim, Joonghan,Jun, Sunhong,Kim, Kyung Hwan,Kim, Tae Wu,Wulff, Michael,Ihee, Hyotcherl American Chemical Society 2012 The journal of physical chemistry. A, Molecules, s Vol.116 No.11
<P>We investigate the structural dynamics of iodine elimination reaction of 1,2-diiodoethane (C<SUB>2</SUB>H<SUB>4</SUB>I<SUB>2</SUB>) in cyclohexane by applying time-resolved X-ray liquidography (TRXL). The TRXL technique combines structural sensitivity of X-ray diffraction and 100 ps time resolution of X-ray pulses from synchrotron and allows direct probing of transient structure of reacting molecules. From the analysis of time-dependent X-ray solution scattering patterns using global fitting based on DFT calculation and MD simulation, we elucidate the kinetics and structure of transient intermediates resulting from photodissociation of C<SUB>2</SUB>H<SUB>4</SUB>I<SUB>2</SUB>. In particular, the effect of solvent on the reaction kinetics and pathways is examined by comparison with an earlier TRXL study on the same reaction in methanol. In cyclohexane, the C<SUB>2</SUB>H<SUB>4</SUB>I radical intermediate undergoes two branched reaction pathways, formation of C<SUB>2</SUB>H<SUB>4</SUB>I–I isomer and direct dissociation into C<SUB>2</SUB>H<SUB>4</SUB> and I, while only isomer formation occurs in methanol. Also, the C<SUB>2</SUB>H<SUB>4</SUB>I–I isomer has a shorter lifetime in cyclohexane by an order of magnitude than in methanol. The difference in the reaction dynamics in the two solvents is accounted for by the difference in solvent polarity. In addition, we determine that the C<SUB>2</SUB>H<SUB>4</SUB>I radical has a bridged structure, not a classical structure, in cyclohexane.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcafh/2012/jpcafh.2012.116.issue-11/jp2078314/production/images/medium/jp-2011-078314_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp2078314'>ACS Electronic Supporting Info</A></P>
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>
Kim, Jeongho,Kim, Kyung Hwan,Oang, Key Young,Lee, Jae Hyuk,Hong, Kiryong,Cho, Hana,Huse, Nils,Schoenlein, Robert W.,Kim, Tae Kyu,Ihee, Hyotcherl The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.19
<P>Characterization of transient molecular structures formed during chemical and biological processes is essential for understanding their mechanisms and functions. Over the last decade, time-resolved X-ray liquidography (TRXL) and time-resolved X-ray absorption spectroscopy (TRXAS) have emerged as powerful techniques for molecular and electronic structural analysis of photoinduced reactions in the solution phase. Both techniques make use of a pump-probe scheme that consists of (1) an optical pump pulse to initiate a photoinduced process and (2) an X-ray probe pulse to monitor changes in the molecular structure as a function of time delay between pump and probe pulses. TRXL is sensitive to changes in the global molecular structure and therefore can be used to elucidate structural changes of reacting solute molecules as well as the collective response of solvent molecules. On the other hand, TRXAS can be used to probe changes in both local geometrical and electronic structures of specific X-ray-absorbing atoms due to the element-specific nature of core-level transitions. These techniques are complementary to each other and a combination of the two methods will enhance the capability of accurately obtaining structural changes induced by photoexcitation. Here we review the principles of TRXL and TRXAS and present recent application examples of the two methods for studying chemical and biological processes in solution. Furthermore, we briefly discuss the prospect of using X-ray free electron lasers for the two techniques, which will allow us to keep track of structural dynamics on femtosecond time scales in various solution-phase molecular reactions.</P>
Kim JeongHo,Yang Chae Eun,Kim Sug Won,Kim Jiye 대한성형외과학회 2023 Archives of Plastic Surgery Vol.50 No.1
Background: The coronavirus disease 2019 (COVID-19) outbreak has had a major impact worldwide. Several countries have implemented restrictions on social interaction (“social distancing”). Several studies have reported that the epidemiology of trauma patients, such as those with facial bone fractures, has changed after COVID-19 pandemic. This study aimed to further explore these specific changes. Methods: This was a retrospective study of patients who presented to a single institution with facial bone fractures between January 1, 2016, and December 31, 2020. Baseline patient demographics, clinical information, type of fracture, etiology, and operative management were compared before and after COVID-19. Results: Of all cases, 3,409 occurred before COVID-19, and 602 occurred after COVID-19. Since the outbreak of COVID-19, the number of patients with facial fractures has not decreased significantly. A significant increase was noted in fractures that occurred outdoors (p<0.001). However, a decrease was observed in operative management between the groups (p<0.001). There was no significant difference in the proportion of assault, fall-down, industrial accident, or roll-down. In contrast, the proportion of traffic accidents and slip-down categories increased significantly (p<0.05). Moreover, a significant decrease was found in the proportion of the sports category (p=0.001) Conclusions: It was confirmed through this study that COVID-19 pandemic also affected epidemiology of facial fractures. Focusing on these changes, it is necessary to develop safety measures to reduce facial fractures.