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Open j.urnal of Genetics 2019年第1期9卷 1-14页

作者： Devendra R. Malaviya Harsh Raman Brian S. Dear Rosy Raman Aj.y K. Roy Pankaj.Kaushal Amaresh Chandra steve j. hughes ICAR—Indian Institute of Sugarcane Research Lucknow India Graham Centre for Agricultural Innovation Wagga Wagga Australia ICAR—Indian Grassland and Fodder Research Institute Jhansi India ICAR—National Institute of Biotic Stress Management Raipur India South Australian Research & Development Institute Urrbrae Australia

Trifolium alexandrinum, an important forage legume, suffers from narrow genetic base. The present investigation was envisaged to reveal the inter- and intra-species genetic diversity and lineage among 64 accessions, representing a global collection, of T. alexandrinum;it’s two probable progenitor species (T. salmoneum and T. subterraneum) and the three genetically distant species (T. repens, T. vesiculosum, T. michelianum). A set of Simple Sequence Repeats (SSR) primer-pairs developed from T. alexandrinum have shown to amplify alleles across the species under study, suggesting utility of the newly developed resource for assessing molecular diversity among Trifolium species. These SSRs markers together with previously reported SSRs, derived from T. repens, enabled to reveal high intra-species polymorphism in T. alexandrinum and successfully discriminate different species investigated in this study. The diverse accessions determined herein provide a superior resource for further breeding of T. alexandrinum. High allelic similarity of T. alexandrinum with T. subterraneum and T. salmoneum indicated close relatedness among the species, suggesting polyphyletic evolution of T. alexandrinum.

关键词： Egyptian Clover Evolution Genetic Resource Molecular Diversity

Transforming bilayer MoS2 into single-layer with strong photoluminescence using UV-ozone oxidation

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Nano Research 2015年第12期8卷 3878-3886页

作者： Weitao Su Naresh Komar steve j. Spencer Ning Dai Debdulal Roy Institute of Materials Physics Hangzhou Dianzi University Hangzhou 310018 China Ningbo Institute of Materials Technology & Engineering Chinese Academy of Sciences Ningbo 315201 China National Physical Laboratory Hampton Road Teddington Middlesex TWI 10LW UK

The use of single-layer MoS2 in light emitting devices requires innovative methods to enhance its low photoluminescence （PL） quantum yield. In this work, we report that single-layer MoS2 with a strong PL can be prepared by oxidizing bilayer MoS2 using W-ozone oxidation. We show that as compared to mechanically-exfoliated single-layer MoS2, the PL intensity of the single-layer MoS2 prepared by W-ozone oxidation is enhanced by 20-30 times. We demonstrate that the PL intensity of both neutral excitons and trions （charged excitons） can be greatly enhanced in the oxidized MoS2 samples. These results provide novel insights into the PL enhancement of single-layer MoS2.

关键词： single-layer MoS2 W-ozone oxidation photoluminescence enhancement tip-enhanced Raman spectroscopy

Thermal convection in ice sheets: New data, new tests

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Natural Science 2012年第7期4卷 409-418页

作者： Terence j. hughes Emeritus of Earth Sciences and Climate Change University of Maine 404 North Sixth Street Fort Pierre South Dakota 57532 USA

Thermal convection in the Antarctic Ice Sheet was proposed in 1970. Demonstrating its existence proved to be elusive. In 2009, tributaries to ice streams were postulated as the surface expression of underlying thermal convection rolls aligned in directions of advective ice flow. Two definitive tests of this hypothesis are now possible, using highly accurate ice elevations and velocities provided by the European, j.panese, and Canadian Space Agencies that allow icestream tributaries and their velocities to be mapped. These tests are 1) measuring lowering of tributary surfaces to see if lowering is due only to advective ice thinning, or also requires lowering en masse in the broad descending part of convective flow, and 2) measuring transverse surface ice velocities to see if ice entering tributaries from the sides increases while crossing lateral shear zones, as would be required if this flow is augmented by convective flow ascending in the narrow side shear zones and diverted into tributaries by advective ice flow. If (1) and (2) are applied to tributaries converging on Byrd Glacier, the same measurements can be conducted when tributaries pack together to become “flow stripes” down Byrd Glacier and onto the Ross Ice Shelf to see if (2) is reduced when lateral advection stops. This could determine if thermal convection remains active or shuts down as ice thins. Thermal convection in the Antarctic Ice Sheet would raise three questions. Can it cause the ice sheet to self-destruct as convective flow turns on and off? Does it render invalid climate records extracted at depth from ice cores? Can the ice sheet be studied as a miniature mantle analogous in some respects to Earth’s mantle?

关键词： Thermal Convection Antarctic Ice Sheet Climate Change Rising Sea Level

Modern Black Sea oceanography applied to the end-Permian extinction event

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j.urnal of Palaeogeography 2015年第1期4卷 52-62页

作者： steve Kershaw Institute for the Environment Health and Societies Brunel UniversityKingston LaneUxbridge Middlesex UB8 3PH UK

The modern Black Sea has a mixed upper layer in the top 150-200 m of the water column, below which the water is anoxic, separated from the mixed layer by a redox boundary. There is limited vertical movement of water. Pyrite framboids form in the water column of the anoxic zone, then have been traditionally interpreted to sink immediately and accumulate in the sediments of the Black Sea. Thus the occurrence of framboids in sediments in the rock record is widely interpreted to indicate poorly oxygenated to anoxic conditions in ancient environments. However, in the Permian-Triassic boundary （PTB） microbialites of South China, which formed in shallow marine conditions in contact with the atmosphere, the published occurrence of framboids is inconsistent with abundant gastropod and ostracod shells in the microbialite. Furthermore, in the modern Black Sea, （a） framboids may be suspended, attached to organic matter in the water column, thus not settle to the sea floor immediately after formation; and （b） the redox zone is an unstable complex area subj.ct to rapid vertical water movement including occasional upwelling. The model presented here supposes that upwelling through the redox zone can lead to upward transport of suspended pyrite framboids into the mixed layer. Advective circulation could then draw suspended framboids onto the shelf to be deposited in oxygenated sediments. In the Permian-Triassic transition, if framboids were upwelled from below the redox boundary and mixed with oxygenated waters, sediment deposited in these conditions could provide a mixed signal for potentially misleading interpretations of low oxygen conditions. However, stratigraphic sampling resolution of post-extinction microbialites is currently insufficient to demonstrate possible separation of framboid-bearing layers from those where framboids are absent. Profound differences between microbialite constructors and sequences between the western and eastern Tethys demonstrate barriers to migra

关键词： mass extinction Permian-Triassic boundary microbialite ostracods gastro-pods anoxia Black Sea

Underground mine stream crossing assessment:A multi-disciplinary approach

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International j.urnal of Mining Science and Technology 2021年第1期31卷 59-65页

作者： Kevin Andrews steve Keim Marshall Miller&Associates BluefieldVA 24605USA

Underground mine designs typically try to avoid extraction beneath streams and rivers of any significant size,especially when the overburden rock thickness between the stream bed and the mine is *** issues with mining beneath streams include excessive groundwater inflow to the mine,weak ground(roof,floor,and pillar)conditions,horizontal stress effects,as well as stream loss and other potential adverse environmental ***,there are times when crossing beneath a stream or river is necessary to move into a new area of mineral reserve without creating additional mine access points from the ground ***,stream crossings are completed without thorough assessment,potentially resulting in increased costs,decreased safety,and,in some cases,failure to advance the *** of the most favorable location(s)to cross the stream must account for numerous factors and the associated assessment often requires a multi-disciplinary *** crossing investigations often require geological,hydrogeological,geotechnical,and geophysical *** of stream crossing investigations include desktop evaluation of maps and aerial photography,stream bed observations,drilling,detailed rock core logging,downhole geophysical surveying,hydraulic conductivity testing(packer testing),geotechnical laboratory testing,assessment,and *** deliverables from a stream crossing assessment typically include geological,geotechnical,and hydrogeological characterization of potential stream crossing locations,classification of favorable and unfavorable crossing locations,recommendations for entry design and pillar sizing,and recommendations for if,and how,to conduct pre-grouting *** of technical aspects of data collection and assessment are provided based on decades of industry experience conducting stream crossing assessments in various underground mining scenarios.

关键词： Underground mining Geotechnical Stream-crossing Hydrogeology Characterization

GEANT4 simulation of gamma ray in a double-gap resistive plate chamber

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Chinese Physics B 2006年第1期15卷 108-115页

作者： j. T. Rhee M. j.mil steve Hall Y. j. j.on Institute for Advanced Physics Physics Department Konkuk University Seoul 143-701 Korea School of Science and Engineering Ballarat University Ballarat Victoria 3353 Australia Department of Chemistry Konkuk University Seoul 143-701 Korea

For more than 20 years nuclear physicists have used the GEANT code to simulate particle-matter interaction. In most recent version, GEANT4 is a toolkit for simulating the passage of particles though matter, which contains a complete range of functionality including tracking, geometry, physics models, and hits. In this article, an attempt to use GEANT4 to model a double-gap resistive plate chamber （RPC） with its improved efficiency is presented. The efficiencies of the double-gap RPC have been evaluated as a function of gamma energy range 0.005-1000MeV. A comparison to available previous simulation package GEANT3 data is also performed.

关键词： GEANT4 Monte Carlo simulation efficiency resistive plate chamber

Suppressed oxygen extraction and degradation of LiNixMnyCo2O2 cathodes at high charge cut-off voltages

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Nano Research 2017年第12期10卷 4221-4231页

作者： j.anming Zheng Pengfei Yan j.andong Zhang Mark H. Engelhard Zihua Zhu Bryant j. Polzin steve Trask j.e Xiao Chongmin Wang j.guang Zhang Energy and Environment Directorate Pacific Northwest National Laboratory 902 Battelle Boulevard Richland WA 99354 USA Environmental Molecular Sciences Laboratory Pacific Northwest National Laboratory 3335 Innovation Boulevard Richland WA 99354 USA Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue Argonne IL 60439 USA

The capacity degradation mechanism in lithium nickel-manganese-cobalt oxide （NMC） cathodes （LiNi1/3Mn1/3Co1/3O2 （NMC333） and LiNi0.4Mn0.4Co0.2O2 （NMC442）） during high-voltage （cut-off of 4.8 V） operation has been investigated. In contrast to NMC442, NMC333 exhibits rapid structural changes including severe micro-crack formation and phase transformation from a layered to a disordered rock-salt structure, as well as interfacial degradation during high-voltage cycling, leading to a rapid increase of the electrode resistance and fast capacity decline. The fundamental reason behind the poor structural and interracial stability of NMC333 was found to be correlated to its high Co content and the significant overlap between the Co3＋/4＋ t2g and O2- 2p bands, resulting in oxygen removal and consequent structural changes at high voltages. In addition, oxidation of the electrolyte solvents by the extracted oxygen species generates acidic species, which then attack the electrode surface and form highly resistive LiF. These findings highlight that both the structural and interfacial stability should be taken into account when tailoring cathode materials for high voltage battery systems.

关键词： layered structure high-voltage cycling structural stability interfacial stability material composition Li-ion battery

Stability of unicortical locked fixation versus bicortical non-locked fixation for forearm fractures

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Bone Research 2014年第2期2卷 131-135页

作者： Timothy j.Pater steve I Grindel Gregory j.Schmeling Mei Wang Department of Orthopaedic Surgery Medical College of Wisconsin Milwaukee WI USA Orthopaedic & Rehabilitation Engineering Center Marquette University Milwaukee WI USA

Locking plate fixation is being widely applied for fixation of forearm fractures and has many potential advantages, such as fixed angle fixation and improved construct stability, especially in osteoporotic bone. Biomechanical data comparing locking devices to commonly used Low Contact Dynamic Compression （LCDCP） plates for the fixation of forearm fractures has been lacking. The purpose of this study was to compare the fixation stability of a 3.5-mm unicortical locked plate with bicortical non-locked LCDCP plates. Six matched pairs of fresh frozen cadaveric forearms were randomly assigned to unicortical locked and bicortical unlocked groups. Non-destructive four-point bending and torsional test was performed on the ulna and radius separately, using a servohydraulic testing system to obtain construct stiffness of the intact specimens and specimens after osteotomy and plating. The specimens were then loaded to failure to test the fixation strength. The locked unicortical fixation showed significantly higher bending stiffness than the unlocked bicortical fixation, but with significantly lower stiffness and strength in torsion. Fixation strength was comparable between the two groups under bending, but significantly greater in the bicortical non-locked group under torsion. Findings from this study suggest that postoperative rehabilitation protocols may need modification to limit torsional loading in the early stage when using locked unicortical fixation. The study also points out the potential advantage of a hybrid fixation that combines locked unicortical and unlocked bicortical screws.

关键词： Stability of unicortical locked fixation versus bicortical non-locked fixation for forearm fractures

Diversity in global gene expression and morphology across a watercress (Nasturtium officinale R. Br.) germplasm collection: first steps to breeding

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Horticulture Research 2015年第1期2卷 175-182页

作者： Adrienne C.Payne Graham j.j.Clarkson steve Rothwell Gail Taylor Centre for Biological Sciences Institute for Life SciencesUniversity of SouthamptonSouthamptonSO171BJUK Vitacress Salads Ltd Lower Link FarmSt Mary BourneAndoverHampshireSP116DBUK

Watercress(Nasturtium officinale ***.)is a nutrient intense,leafy crop that is consumed raw or in soups across the globe,but for which,currently no genomic resources or breeding programme *** morphological,biochemical and functional genomic variation was identified for the first time in a newly established watercress germplasm collection,consisting of 48 watercress accessions sourced from contrasting global *** length,stem diameter and anti-oxidant(AO)potential varied across the *** variation was used to identify three extreme contrasting accessions for further *** in global gene expression was investigated using an Affymetrix Arabidopsis ATH1 microarray gene chip,using the commercial control(C),an accession selected for dwarf phenotype with a high AO potential(dwarfAO,called‘Boldrewood’)and one with high AO potential alone.A set of transcripts significantly differentially expressed between these three accessions,were identified,including transcripts involved in the regulation of growth and development and those involved in secondary *** particular,when differential gene expression was compared between C and dwarfAO,the dwarfAO was characterised by increased expression of genes encoding glucosinolates,which are known precursors of phenethyl isothiocyanate,linked to the anti-carcinogenic effects well-documented in *** study provides the first analysis of natural variation across the watercress genome and has identified important underpinning information for future breeding for enhanced anti-carcinogenic properties and morphology traits in this nutrient-intense crop.

关键词： breeding dwarf germplasm

N-Nitrosamine formation from chloramination of two common ionic liquids

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j.urnal of Environmental Sciences 2020年第1期32卷 341-348页

作者： Ian j.Vander Meulen Ping j.ang Di Wu steve E.Hrudey Xing-Fang Li Division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyFaculty of Medicine and DentistryUniversity of Alberta

Ionic liquids(ILs)are a class of solvents increasingly used as"green chemicals."Widespread applications of ILs have led to concerns about their accidental entry to the *** have been assessed for some environmental impacts;however,little has been done to characterize their potential impacts on drinking water if ILs accidentally enter surface *** cations are often aromatic or alkyl quaternary amines that resemble structures of previously confirmed N-nitrosamine(NA)***,this study has evaluated two common ILs,1-ethyl-3-methylimidazolium bromide(EMIm Br)and 1-ethyl-1-methylpyrrolidinium bromide(EMPyr Br),for their NA formation *** IL species was reacted with pre-formed monochloramine under various laboratory *** reaction mixtures were extracted using liquid–liquid extraction and analyzed for NAs using high performance liquid chromatography tandem mass *** low concentration of IL(250μmol/L),the yields of NAs(NMEA or NPyr)increased with increasing doses of monochloramine from both IL *** total NA yield was as high as 2.5±0.3 ng/mg from EMIm Br,and as high as 8.6±0.8 ng/mg from EMPyr *** high concentration of IL(5 mmol/L),the NA yield reached a maximum at 2.5 mmol/L NH2Cl,and then decreased with subsequent increases in the reactant concentrations,demonstrating ILs’solvent *** study re-emphasizes the importance of preventing discharge of ILs to water bodies to prevent secondary impacts on drinking water.

关键词： Ionic liquids N-nitrosamine Liquid–liquid extraction HPLC–MS/MS DBPs