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A new currency for mutualism?Fungal endophytes alter antioxidant activity in hosts responding to drought

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Fungal Diversity 2012年第3期54卷 39-49页

作者： Cyd e.hamilton Taryn L.Bauerle MTT Agrifood and Biotech Plant Production UnitJokioinenFinland Cornell University HorticultureIthacaNYUSA

Fungal endophytes have significant effects on host performance including but not limited to changes in reproductive output,as well as,biotic and abiotic stress *** ultimate mechanisms for resistance to herbivory have been documented in a number of fungal-plant symbiota and involve the production of alkaloids by the *** have thus been defined as a currency responsible for increased host resistance to *** provide support for the hypothesis that another currency may be responsible for increased host tolerance to abiotic stress resulting from endophyte colonization;namely *** report comparatively higher activity of antioxidants in endophyte colonized hosts resulting from abiotic stress and propose antioxidants are another currency via which mutualistic interactions between fungal endophytes and their hosts can *** recognize fungal endophyte interactions are diverse and complex and include antagonisms,commensalisms,and mutualisms.

关键词： Symbiont Stress epichloe Neotyphodium Stress tolerance Reactive oxygen species

endophytic mediation of reactive oxygen species and antioxidant activity in plants:a review

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Fungal Diversity 2012年第3期54卷 1-10页

作者： Cyd e.hamilton P.e.Gundel M.Helander K.Saikkonen MTT Agrifood Research Finland Plant Production ResearchFI-31600 JokioinenFinland IFeVA-CONICeT-Faculty of Agronomy Buenos Aires University(UBA)Buenos AiresArgentina Section of ecology Department of BiologyUniversity of Turku20014 TurkuFinland

Reactive oxygen species are in all types of organisms from microbes to higher plants and *** are by-products of normal metabolism,such as photosynthesis and respiration,and are responsive to abiotic and biotic *** evidence suggests reactive oxygen species play a vital role in programmed cell death,stress responses,plant defense against pathogens and systemic stress signaling in conjunction with antioxidant ***,we propose that reactive oxygen species and antioxidants,as both universal and evolutionarily conserved,are likely to play important role(s)in symbiotic *** support this hypothesis we review the root and foliar fungal endophyte literature specific to fungal-plant symbiotum production of reactive oxygen species and antioxidants in response to *** asymptomatic fungi can produce antioxidants in response to both biotic and abiotic stress when grown in culture as well as in *** addition,there is a growing but nascent literature reporting a significant impact of endophyte colonization on the antioxidant activity of colonized(e+)hosts when compared to uncolonized(e-)hosts,especially when exposed to *** we summarize general patterns emerging from the growing literature specific to antioxidant activity of endophytes in colonized hosts and bring up possible future research questions and *** consequences of changes in reactive oxygen species production and increased antioxidant activity in the symbiotum appear to be beneficial in many instances;but costs are also *** questions are:1)to what extent do antioxidants originating from the fungal endophyte mediate host metabolism,and thereby control host responses to endophyte colonization;(2)what role do fungal,plant,or symbiotum produced reactive oxygen species and antioxidants have in determining symbiotic outcome between extremes of pathogenicity and mutualism;and(3)what role if any,do the production of reactive oxygen speci

关键词： endophyte Symbiosis Neotyphodium epichloë Mutualism Dark septate endophytes Antagonism Stress Pathogen

Radical Addition of Perfluorinated Alkyl Iodides to Multi- Layered Graphene and Single-Walled Carbon Nanotubes

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Nano Research 2010年第2期3卷 138-145页

作者： Christopher e.hamilton Jay R.Lomeda Zhengzong Sun James M.Tour Andrew R.Barron Richard e.Smalley Institute for Nanoscale Science and Technology Department of Chemistry and Department of Mechanical Engineering and Materials ScienceRice UniversityHoustonTexas 77005USA

A simple one-pot reaction that serves to functionalize graphite nanosheets(graphene)and single-walled carbon nanotubes(SWNTs)with perfluorinated alkyl groups is *** radical addition of 1-iodo-1H,1H,2H,2H-perfluorododecane to ortho-dichlorobenzene suspensions of the carbon nanomaterial is initiated by thermal decomposition of benzoyl ***,UV photolysis of 1-iodo-perfluorodecane serves to functionalize the carbon ***-SWNTs,perfluorododecyl-graphene,and perfluorodecyl-graphene are characterized by infrared(IR)and Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA),and atomic force microscopy(AFM).The products show enhanced dispersability in CHCl3 as compared to unfunctionalized starting *** advantage of this one-pot functionalization procedure lies in the use of pristine graphite as starting material thereby avoiding the use of harsh oxidizing conditions.

关键词： Nanotube single-walled carbon nanotube graphene radical addition

Neotyphodium fungal endophyte in tall fescue (Schedonorus phoenix): a comparison of three Northern european wild populations and the cultivar Kentucky-31

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Fungal Diversity 2013年第3期60卷 15-24页

作者： Pedro e.Gundel Marjo Helander Cecilia Casas Cyd e.hamilton Stanley H.Faeth Kari Saikkonen MTT Agrifood Research Finland Plant Production Research31600 JokioinenFinland IFeVA-CONICeT–Faculty of Agronomy Buenos Aires University(UBA)Buenos AiresArgentina Department of Biology Section of EcologyUniversity of Turku20014 TurkuFinland Soil Science Division Faculty of AgronomyBuenos Aires University(UBA)Buenos AiresArgentina Department of Biology University of North CarolinaGreensboroNC 27402-6170USA

Pooideae grasses may be colonized by systemic fungal *** fitness of endophyte depends entirely on resources and seed transmission from the host plant,while colonized plants may gain increased survival,growth,and reproduction relative to their uncolonized *** research of endophyte-grass interactions have been carried out on few cultivars of tall fescue(Schedonorus phoenix)and their symbiont Neotyphodium *** of studies using wild populations of tall fescue across the species natural distribution range,however,limits the understanding of the ecological and evolutionary role of the symbiosis in *** performed a common garden experiment in Southern Finland with three wild,tall fescue populations from northern europe and the forage cultivar Kentucky-31(KY-31).For each population,we used naturally endophyte-colonized,naturally endophytecolonized but endophyte removed(decolonized),and naturally uncolonized plants to separate effects due to the host genotype from the *** evaluated growth variables and survival in four environmental treatments of varying water and *** of water and nutrients increased plant biomass and reproductive effort in all *** effect was higher for KY-31 plants which produced on average 55%more seeds than wild plants,indicating better adaptation to high resource ***,the higher incidence of Claviceps *** the low winter survival indicated KY-31 tall fescue is mal-adapted to Northern european *** colonized plants had greater plant biomass(≈12%),reproductive effort(≈22%)and seed mass(≈29%)than naturally uncolonized and decolonized ***,endophyte colonization did not affect plant survival,and the effects of endophyte colonization on tiller number,panicle/tiller ratio and Claviceps *** depended on the population *** the wild populations,endophyte removal only reduced the number of tillers(≈29%lower),while the differen

关键词： Plant-microbial symbiosis Grass Symbiosis Vertically transmitted symbiont Claviceps

Softening of phonon spectra in metallic glasses

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npj Computational Materials 2016年第1期2卷 31-35页

作者： Reza Mahjoub nicholas e.hamilton Kevin J Laws Michael Ferry School of Materials Science and engineering The University of New South WalesSydneyNSWAustralia

The vibrational spectra of a series of MgZnCa amorphous alloys were computed using density functional theory and implementing the small displacement *** atomic structures of the alloys were obtained by ab initio molecular dynamics *** vibrational thermodynamic properties were calculated as a function of temperature and,in particular,the specific heat at low temperature was approximated by temperature cubed based on the Debye *** computed the contribution of Mg vibrations to the specific heat and investigated the softening of Mg phonon spectra,where the maximum allowed vibrational frequency is lowered and highly collective diffusion processes are *** statistical correlation between the reported critical casting thickness of the alloys and softening of Mg phonons was *** calculations were performed for two distinctively different amorphous ZrTiCuAl alloys with large and small reported critical casting thickness,*** findings were consistent with those of the MgZnCa alloys.

关键词： alloys softening casting

First demonstration of an all-solid-state optical cryocooler

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Light(Science & Applications) 2018年第1期7卷 922-931页

作者： Markus P.Hehlen Junwei Meng Alexander R.Albrecht eric R.Lee Aram Gragossian Steven P.Love Christopher e.hamilton Richard I.epstein Mansoor Sheik-Bahae Los Alamos National Laboratory P.O.Box 1663Los AlamosNM 87545USA Department of Physics&Astronomy University of New MexicoAlbuquerqueNM 87131USA

Solid-state optical refrigeration uses anti-Stokes fluorescence to cool macroscopic objects to cryogenic temperatures without *** such as Yb3+-doped YLiF4(YLF:Yb)have previously been laser-cooled to 91 *** this study,we show for the first time laser cooling of a payload connected to a cooling crystal.A YLF:Yb crystal was placed inside a Herriott cell and pumped with a 1020-nm laser(47 W)to cool a HgCdTe sensor that is part of a working Fourier Transform Infrared(FTIR)spectrometer to 135 *** first demonstration of an all-solid-state optical cryocooler was enabled by careful control of the various desired and undesired heat *** heating of the payload was minimized by using a single-kink YLF thermal link between the YLF:Yb cooling crystal and the copper coldfinger that held the HgCdTe *** adhesive-free bond between YLF and YLF:Yb showed excellent thermal *** laser-cooled assembly was then supported by silica aerogel cylinders inside a vacuum clamshell to minimize undesired conductive and radiative heat loads from the warm *** structure can serve as a baseline for future optical cryocooler devices.

关键词： optical pumped desired

SeRVICe VALUe NeTWORKS:INTO PRACTICe

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Journal of Systems Science and Systems engineering 2007年第4期16卷 414-423页

作者： John hamilton Director of e-Business James Cook UniversityCairns4870Australia

Modeling a business to match its customer perceived （and customer desired） outcomes, remains an on-going task. This paper considers shows how a service value networks （SVNs） approach may be engaged to model, and deliver, understanding of the front-end business and its direct engagement with its immediate （or front-end） customers. These front-end customers may be either：（1） its off-line, in-store customers - engaging directly with the business sales staff （or representative）, or-（2） its on-line, virtual customers - engaging with the business via internet or remote access. In this situation, both the business, and the customer draw upon their respective viewpoints, and both sides influence the interaction. external to these business and customer influences are additional factors that capture the immediate and broader global effects - termed environmental effects. These three business-customer engagement areas of influence are captured by a SVN SeM approach. Without a business-customer encounter of some kind the likelihood of a services business, and a prospecting customer, successfully engaging in an exchange process is reduced. This exchange may be a physical, and/or services exchange, and/or an information and/or ideas exchange. To the business, this encounter is, in effect, a trade, and as a result, the business targets acquiring an economic exchange that will ultimately deliver a net positive economic outcome. To the customer, external and internal information feeds, servicing, perceived value, and satisfaction, are key encounter drivers. SVNs offers a new way to understand the business-customer encounter, and to then utilize this acquired knowledge to either：（1） build a strategic management model, or （2） reengineer its business networks, and to then create a re-positioned, more customer-aligned business operation - one that is capable of delivering win - win, competitive business-customer solutions.

关键词： Service value networks alignment structural equation modeling

BeNCHMARKING ON-LINe SeRVICeS INDUSTRIeS

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Journal of Systems Science and Systems engineering 2006年第1期15卷 48-69页

作者： John hamilton Director of e-Business James Cook University Cairns 4870 Australia

The Web Quality Analyser (WQA) is a new benchmarking tool for industry. It has been extensively tested across services industries. Forty five critical success features are presented as measures that capture the user’s perception of services industry websites. This tool differs to previous tools, in that it captures the information technology (IT) related driver sectors of website performance, along with the marketing-services related driver sectors. These driver sectors capture relevant structure, function and performance components. An ‘on-off’ switch measurement approach determines each component. Relevant component measures scale into a relative presence of the applicable feature, with a feature block delivering one of the sector drivers. Although it houses both measurable and a few subjective components, the WQA offers a proven and useful means to compare relevant websites. The WQA defines website strengths and weaknesses, thereby allowing for corrections to the website structure of the specific business. WQA benchmarking against services related business competitors delivers a position on the WQA index, facilitates specific website driver rating comparisons, and demonstrates where key competitive advantage may reside. This paper reports on the marketing-services driver sectors of this new benchmarking WQA tool.

关键词： Benchmarking performance website service analysis compare

effects of N on Plant Response to Heat-wave:A Field Study with Prairie Vegetation

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Journal of Integrative Plant Biology 2008年第11期50卷 1416-1425页

作者： Dan Wang Scott A. Heckathorn Kumar Mainali e. William hamilton Department of environmental Sciences University of Toledo Toledo Ohio 43606 USA Department of Biology Washington and Lee University Lexington Virginia 24450 USA

More intense, more frequent, and longer heat-waves are expected in the future due to global warming, which could have dramatic ecological impacts. Increasing nitrogen （N） availability and its dynamics will likely impact plant responses to heat stress and carbon （C） sequestration in terrestrial ecosystems. This field study examined the effects of N availability on plant response to heat-stress （HS） treatment in naturally-occurring vegetation. HS （5 d at ambient or 40.5 ℃） and N treatments （±N） were applied to 16 1 m^2 plots in restored prairie vegetation dominated by Andropogon gerardii （warm-season C4 grass） and Solidago canadensis （warm-season C3 forb）. Before, during, and after HS, air, canopy, and soil temperature were monitored; net CO2 assimilation （Pn）, quantum yield of photosystem Ⅱ （ФpsⅡ）, stomatal conductance （gs）, and leaf water potential （ψw） of the dominant species and soil respiration （Rsoll） of each plot were measured daily during HS. One week after HS, plots were harvested, and C% and N% were determined for rhizosphere and bulk soil, and above-ground tissue （green/senescent leaf, stem, and flower）. Photosynthetic N-use efficiency （PNUe） and N resorption rate （NRR） were calculated. HS decreased Pn, gs, ψw, and PNUe for both species, and ＋N treatment generally increased these variables （±HS）, but often slowed their post-HS recovery. Aboveground biomass tended to decrease with HS in both species （and for green leaf mass in S. canadensis）, but decrease with ＋N for A. gerardii and increase with ＋N for S. canadensis. For A. gerardii, HS tended to decrease N% in green tissues with ＋N, whereas in S. canadensis, HS increased N% in green leaves. Added N decreased NRR for A. gerardii and HS increased NRR for S. canadensis. These results suggest that heat waves, though transient, could have significant effects on plants, communities, and ecosystem N cycling, and N can influence the effect of heat waves.

关键词： global climate change heat stress N resorption rate photosynthesis photosynthetic N-use efficiency.