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Dyson, Bryony S.,Burton, Jonathan W.,Sohn, Te-ik,Kim, Byungsook,Bae, Hoon,Kim, Deukjoon American Chemical Society 2012 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.134 No.28
<P>Elatenyne is a small dibrominated natural product first isolated from Laurencia elata. The structure of elatenyne was originally assigned as a pyrano[3,2-<I>b</I>]pyran on the basis of NMR methods. Total synthesis of the originally proposed pyrano[3,2-<I>b</I>]pyran structure of elatenyne led to the gross structure of the natural product being reassigned as a 2,2′-bifuranyl. The full stereostructure of this highly flexible small molecule was subsequently predicted by Boltzmann-weighted DFT calculations of <SUP>13</SUP>C NMR chemical shifts for all 32 potential diastereomers, with the predicted structure being in accord with the proposed biogenesis outlined below. Herein we report two complementary total syntheses of elatenyne, which confirm the computer-predicted stereostructure. Additionally, the total syntheses of (<I>E</I>)-elatenyne and a related 2,2′-bifuranyl, laurendecumenyne B, are reported. This work has not only allowed the full structure determination of all of these natural products but also provides excellent supporting evidence for their proposed biogenesis. The total synthesis of elatenyne demonstrates that DFT calculations of <SUP>13</SUP>C NMR chemical shifts coupled with biosynthetic postulates, comprise a very useful method for distinguishing among large numbers of highly flexible, closely related molecules.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2012/jacsat.2012.134.issue-28/ja304554e/production/images/medium/ja-2012-04554e_0011.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja304554e'>ACS Electronic Supporting Info</A></P>
Maree Dyson,Sally Canobi 한국사회복지학회 2011 Asian Social Work and Policy Review Vol.5 No.2
Social insurance schemes in Australasia have a long-standing involvement in leading systemicchange as well as funding services for eligible scheme participants. Establishing a long-term disabilitycare and support scheme for Australia provides opportunities to remove barriers to communityaccess and improve the employment participation of all Australians with a disability, and toincrease the use of evidence in policy development and in the delivery of disability supports. Usingthe examples of successful models in Australia and New Zealand, the authors will propose a modelfor the development and management of a long-term disability care and support scheme thatenables sector reform in employment participation, barriers to access and participation in all aspectsof community life, and funding of disability research to benefit all Australians with a disability.
Phonon emission and arrival times of electrons from a single-electron source
Emary, C.,Dyson, A.,Ryu, Sungguen,Sim, H.-S.,Kataoka, M. American Physical Society 2016 Physical Review B Vol.93 No.3
<P>In recent charge-pump experiments, single electrons are injected into quantum Hall edge channels at energies significantly above the Fermi level. We consider here the relaxation of these hot edge-channel electrons through longitudinal-optical-phonon emission. Our results show that the probability for an electron in the outermost edge channel to emit one or more phonons en route to a detector some microns distant along the edge channel suffers a double-exponential suppression with increasing magnetic field. This explains recent experimental observations. We also describe how the shape of the arrival-time distribution of electrons at the detector reflects the velocities of the electronic states post phonon emission. We show how this can give rise to pronounced oscillations in the arrival-time-distribution width as a function of magnetic field or electron energy.</P>
( Octavio Godinez ),( Paul Dyson ),( Ricardo Del Sol ),( Javier Barrios Gonzalez ),( Cesar Millan Pacheco ),( Armando Mejia ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11
The transition from primary to secondary metabolism in antibiotic-producing Streptomyces correlates with expression of genes involved in stress responses. Consequently, regulatory pathways that regulate specific stress responses are potential targets to manipulate to increase antibiotic titers. In this study, genes encoding key proteins involved in regulation of the osmotic stress response in Streptomyces avermitilis, the industrial producer of avermectins, are investigated as targets. Disruption of either osaBSa, encoding a response regulator protein, or osaCSa, encoding a multidomain regulator of the alternative sigma factor SigB, led to increased production of both oligomycin, by up to 200%, and avermectin, by up to 37%. The mutations also conditionally affected morphological development; under osmotic stress, the mutants were unable to erect an aerial mycelium. In addition, we demonstrate the delivery of DNA into a streptomycete using biolistics. The data reveal that information on stress regulatory responses can be integrated in rational strain improvement to improve yields of bioactive secondary metabolites.
Querzoli, Adrian L.,Hoadley, Andrew F.A.,Dyson, Tony E.S. 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.4
This study investigates improving the energy efficiency of two key refining processes: the Crude Distillation Unit (CDU) and the Residue Cracking Unit (RCU). The research methodology followed the ‘targeting before design’ approach. The CDU is a ‘tightly pinched’ system, with limited opportunities for further energy savings. The RCU actual △T_(min) is around 55℃ indicating a low level of current heat recovery. The Total-Site analysis shows that theoretically 18MW of heat could be transferred from the RCU to the CDU, reducing CDU requirements by 40% for a new or grass roots design. RCU retrofit designs were developed to increase steam generation by up to 35% and in line with targeting estimates would appear to have economic potential. The alternative CDU-RCU retrofit design was developed to decrease CDU hot utility use. Although the Total-Site profile demonstrated strong potential for heat integration, this retrofit design is not commercially attractive, as the decrease in CDU fuel does not offset the cost of reduced steam generation. This demonstrates the need to consider the different fuel and steam costs in the Total-Site analysis.
International Harmonisation of Pesticide Environmental Safety Assessments
디 라일리,제이 다이슨,Riley, D.,Dyson, J. 한국잡초학회 1997 Weed&Turfgrass Science Vol.17 No.1
Governments and industry have a growing interest in the harmonization of environmental test methods and risk assessment procedures. OECD are currently producing a set of harmonised test guidelines for studying the environmental fate and ecological effects of pesticides. FAO has published an environmental risk assessment procedure. This procedure, which is similar to those used in US and Europe, is based on calculating the ratio of the toxicity of a pesticide to indicator organisms to their level of exposure to the pesticide. The exposure depends on both the concentration of the pesticide and its bioavailability. Ratios which indicate a pesticide will not produce a harmful effect have been established using ecological field studies. Examples are presented for assessing the risk to aquatic ecosystems, earthworms and honeybees. Long-term field studies(up to 20 years) have also shown that pesticides can be used indefinitely without harming soil fertility. Herbicides can be used to avoid the ecologically damaging effects of using soil cultivations excessively for weed control.