检索结果-南通市图书馆

Frontiers of Environmental Science & Engineering 2024年第4期18卷 103-110页

作者： Mathias Fessler Qingxian Su Marlene Mark Jensen Yifeng Zhang Department of Environmental and Resource Engineering Technical University of DenmarkCopenhagenDK-2800Denmark

Magnetotactic bacteria reside in sediments and stratified water *** are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field ***,we show that two magnetotactic species,Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1,are *** *** and *** were able to generate current in microbial fuel cells with maximum power densities of 27 and 11μW/m^(2),*** the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite(Fe_(2)O_(3)).In addition,*** could reduce poorly crystalline iron oxide(FeOOH).Our study adds *** and *** to the growing list of known electroactive bacteria,and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

关键词： Magnetotactic bacteria Magnetospirillum magneticum Magnetospirillum gryphiswaldense Extracellular electron transfer Microbial fuel cells

Quantifying and sorting of gold nanoparticle dimers from complex reaction mixtures using flow cytometry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2016年第10期9卷 3093-3098页

作者： Jens B. Simonsen Nini E. A. Reeler Anna Fossum Knud A. Lerstrup Bo W. Laursen Kasper Nergaard Universitetsparken 5 Nano-Science Center & Department of Chemistry University of Copenhagen Copenhagen DK-2100 Denmark Niels Jensens Vej 2 Sino-Danish Centre for Education and Research (SDC) Aarhus DK-8000 Denmark Ole Maaloes Vej 5 Biotech Research and Innovation Centre (BRIC) University of Copenhagen Copenhagen DK-2200 Denmark

The formation, characterization, and purification of well-defined stoichiometric clusters of metallic nanoparticles, particularly in the form of dimers or trimers, are important and formidable challenges in nanoscience. Here we show that flow cytometry can be used as a high-throughput method to determine the relative distribution of oligomeric clusters of molecularly linked gold nano- particles in bulk solution at the single-particle level with good statistics. This unique information would be near impossible to obtain using traditional characterization techniques. The flow cytometric approach is utilized to provide fast feedback for the synthesis optimization of the complex reaction between citrate-stabilized gold nanoparticles and bi-functional molecular wires with dithiocarbamate anchoring groups. Finally, we demonstrate that flow cytometry can be used to significantly increase the proportion of AuNP dimers from an oligomer-rich polydisperse sample by size-selective sorting.

关键词： flow cytometry characterization sorting nanoparticles gold nanoparticle dimers

Application of heat shock protein expression for detecting natural adaptation and exposure to stress in natural populations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2010年第6期56卷 703-713页

作者： Jesper Givskov SφRENSEN National Environmental Research Institute Aarhus UniversityDepartment of Terrestrial Ecology

Heat-shock proteins （HSPs） play an undisputed role for maintaining cellular functioning under environmental challenges and protein denaturing conditions. Compelling evidence points to an evolutionary important role of HSPs and a strict evolutionary control of these proteins as a balance between benefits and costs. While there is a great potential for using HSP expression for detecting natural adaptation and exposure to stress in natural populations, some obstacles and key issues await investigation. From an ecological perspective these key issues needs to be resolved in order to fully appreciate the complex responses and adaptations to stress and to increase our understanding of HSPs and other molecular chaperones for stress adaptation and potential use as biomarkers. Here, the current knowledge and understanding of HSPs is reviewed and a number of key issues including the interpretation of elevated HSP levels, the complications of extrapolating between laboratory and field conditions, the effects of choice of traits and methodology and the larger intra-and extracellular networks of interactions that HSPs participate in are discussed [Current Zoology 56 （6）： 703-713, 2010].

关键词： Biomarker Hsp Molecular chaperone Thermal adaptation Thermal stress

Umamification of food facilitates the green transition

在线全文

学校读者我要写书评

暂无评论

Soil Ecology Letters 2023年第1期5卷 1-3页

作者： Ole G.Mouritsen Department of Food Science Taste forLifeDesign and Consumer BehaviorUniversity of Copenhagen26 RolighedsvejDK-1958 FrederiksbergDenmark

The planet is facing a global climate *** have urgently to be taken to alleviate the consequences by diminishing emission of greenhouse gases,cutting fossil energy consumption,and implementing sustainable uses of the world's *** responsible for more than one third of the stressors on the climate,the global food production systems and our eating behavior must change dramatically(Vermeulen et al.,2012).

关键词： planet consequences gases

Corundum formation by metasomatic reactions in Archean metapelite,SW Greenland:Exploration vectors for ruby deposits within high-grade greenstone belts

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第3期9卷 727-749页

作者： Chris Yakymchuk Kristoffer Szilas Earth and Environmental Sciences University of Waterloo200 University Ave WestWaterlooOntario N2L 3G1Canada Geological Survey of Denmark and Greenland(GEUS) Oter Voldgade 101350 Copenhagen KDenmark

Corundum(ruby-sapphire) is known to have formed in situ within Archean metamorphic rocks at several localities in the North Atlantic Craton of Greenland. Here we present two case studies for such occurrences:(1) Maniitsoq region(Kangerdluarssuk), where kyanite paragneiss hosts ruby corundum, and(2)Nuuk region(Stor?), where sillimanite gneiss hosts ruby corundum. At both occurrences, ultramafic rocks(amphibole-peridotite) are in direct contact with the ruby-bearing zones, which have been transformed to mica schist by metasomatic reactions. The bulk-rock geochemistry of the ruby-bearing rocks is consistent with significant depletion of SiO_2 in combination with addition of Al_2O_3, MgO, K_2O,Th and Sr relative to an assumed aluminous precursor metapelite. Phase equilibria modelling supports ruby genesis from the breakdown of sillimanite and kyanite at elevated temperatures due to the removal of SiO_2. The juxtaposition of relatively silica-and aluminum-rich metasedimentary rocks with low silica ultramafic rocks established a chemical potential gradient that leached/mobilized SiO_2 allowing corundum to stabilize in the former rocks. Furthermore, addition of Al_2O_3 via a metasomatic reaction is required, because Al/Ti is fractionated between the aluminous precursor metapelites and the resulting corundum-bearing mica schist. We propose that Al was mobilized either by complexation with hydroxide at alkaline conditions, or that Al was transported as K-Al-Si-O polymers at deep crustal *** three main exploration vectors for corundum within Archean greenstone belts are:(1) amphiboliteto granulite-facies metamorphic conditions,(2) the juxtaposition of ultramafic rocks and aluminous metapelite, and(3) mica-rich reactions zones at their interface.

关键词： Ultramafic rocks Kyanite Sillimanite Metasomatism Pseudosection Desilicification

Directly imaging of the atomic structure of luminescent centers in CaYAlO_(4):Ce^(3+)

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第2期16卷 3004-3009页

作者： Yalong Zhai Xuewei Yang Shu-Na Zhao Pei Liu Jun Lin Yang Zhang School of Materials Science and Engineering Center of Advanced Analysis&Gene SequencingZhengzhou UniversityZhengzhou 450001China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China DTU Nanolab.Technical University of Denmark Fysikvej2800 Kgs.LyngbyDenmark Green Catalysis Center and College of Chemistry Zhengzhou UniversityZhengzhou 450001China

Lanthanides(Ln^(3+))doped luminescent materials play critical roles in lighting and display *** increasing experimental and theoretical research have been carried out on aluminate-based phosphors for white light-emitting diodes(WLEDs)over the past decades,most investigation was mainly focused on their luminescent properties;therefore,the local structure of the light emission center remains ***,doping-induced local composition and structure modification around the luminescent centers have yet to be *** this study,we use advanced electron microscopy techniques including electron diffraction(ED),high-resolution transmission electron microscopy(HRTEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),in combination with energy dispersive X-ray spectroscopy(EDX)and electron energy loss spectroscopy(EELS),to reveal atomically resolved crystalline and chemical structure of Ce^(3+)doped *** microscopic results prove substantial microstructural and compositional inhomogeneities in Ce^(3+)doped CaYAlO_(4),especially the appearance of Ce dopant clustering and Ce^(3+)/Ce^(4+)valence *** research provides a new understanding the structure of Ln^(3+)doped luminescent materials and will facilitate the materials design for next-generation WLEDs luminescent materials.

关键词： luminescent white light-emitting diodes(WLEDs) rare earth element atomic structure chemical structure

Nanostructure and mechanical properties of the osteocyte lacunar-canalicular network-associated bone matrix revealed by quantitative nanomechanical mapping

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2015年第10期8卷 3250-3260页

作者： Shuai Zhang Fiona Linnea Bach-Gansmo Dan Xia Flemming Besenbacher Henrik Birkedal Mingdong Dong TheInterdisciplinaryNanoscienceCenter AarhusUniversityAarhusC8000Denmark DepartmentofChemistry AarhusUniversityAarhusC8000Denmark

Osteocytes are the main bone cells embedded in the bone matrix where they form a large surface-area network called the lacunar-canalicular network （LCN）, interconnecting their resident spaces with the lacunae by the canaliculi. Increasing evidence points toward osteocytes playing a pivotal role in maintaining bone quality. On the one hand, osteocytes transmit mechanical strain and microenvironmental signals through the LCN to regulate the activity of osteoblasts and osteoclasts; on the other hand, osteocytes are suggested to be able to remodel the LCN-associated bone matrix. However, due to the challenges involved in the assessment and characterization of the LCN-associated bone matrix, little is known about its structure and the corresponding mechanical properties. In this work, we used quantitative nanomechanical mapping, backscattered electron imaging, and nanoindentation to characterize the LCN-associated bone matrix. The results show that the techniques can be used to probe the LCN-associated bone matrix. Nanoindentation and quantitative mechanical mapping reveal spatially inhomogeneous mechanical properties of the bone matrix associated with the osteocyte lacunae and canaliculi. The obtained nano-topography and corresponding nano-mechanical maps reveal altered mechanical properties in the immediate vicinity of the osteocyte lacunae and canaliculi, which cannot be explained solely by the topographic change.

关键词： lacunar-canalicularnetwork osteocyte perilacunar bone matrix pericanalicular bone matrix reduced modulus mechanical properties

Ancient environmental DNA reveals Arctic ecosystem dynamics in last 50,000 years

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2022年第13期67卷 1304-1306页

作者： Yucheng Wang Department of Zoology University of CambridgeCambridge CB23EJUK Lundbeck foundation GeoGenetics Centre GLOBE InstituteUniversity of CopenhagenCopenhagen K1350Denmark BGI BGI-ShenzhenShanghai 201321China Group of Alpine Paleoecology and Human Adaptation(ALPHA) State Key Laboratory of Tibetan Plateau Earth SystemResources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Much focus is currently placed on human-caused climate change and how it may influence living organisms, i.e., biodiversity in general and the humanity associated with it, particularly in the circumpolar where the ecosystem is more vulnerable, and the climate change is amplified due to the inherent instability of high latitude climates [1].

关键词： climate Arctic latitude

Highly refractory Archaean peridotite cumulates:Petrology and geochemistry of the Seqi Ultramafic Complex,SW Greenland

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第3期9卷 689-714页

作者： Kristoffer Szilas Vincent van Hinsberg Iain McDonald Tomas Naeraa Hugh Rollinson Jacob Adetunji Dennis Bird Department of Geological Sciences Stanford University450 Serra MallStanfordCA 94305USA Department of Earth&Planetary Sciences McGill UniversityQuebecCanada Department of Geology Lund UniversitySovegatan 12223 62 LundSweden School of Earth and Ocean Sciences Cardiff UniversityMain BuildingCardiff CF10 3ATUnited Kingdom College of Science University of DerbyDerbyDE22 1GBUK

This paper investigates the petrogenesis of the Seqi Ultramafic Complex, which covers a total area of approximately 0.5 km^2. The ultramafic rocks are hosted by tonalitic orthogneiss of the ca. 3000 Ma Akia terrane with crosscutting granitoid sheets providing an absolute minimum age of 2978 ± 8 Ma for the Seqi Ultramafic Complex. The Seqi rocks represent a broad range of olivine-dominated plutonic rocks with varying modal amounts of chromite, orthopyroxene and amphibole, i.e. various types of dunite(s.s.),peridotite(s.l.), as well as chromitite. The Seqi Ultramafic Complex is characterised primarily by refractory dunite, with highly forsteritic olivine with core compositions having Mg# ranging from about 91 to 93. The overall high modal contents, as well as the specific compositions, of chromite rule out that these rocks represent a fragment of Earth's mantle. The occurrence of stratiform chromitite bands in peridotite, thin chromite layers in dunite and poikilitic orthopyroxene in peridotite instead supports the interpretation that the Seqi Ultramafic Complex represents the remnant of a fragmented layered complex or a magma conduit, which was subsequently broken up and entrained during the formation of the regional continental *** all of the characteristics of the Seqi Ultramafic Complex points to formation of these highly refractory peridotites from an extremely magnesian(Mg# ~ 80), near-anhydrous magma, as olivinedominated cumulates with high modal contents of chromite. It is noted that the Seqi cumulates were derived from a mantle source by extreme degrees of partial melting(>40%). This mantle source could potentially represent the precursor for the sub-continental lithospheric mantle(SCLM) in this region,which has previously been shown to be ultra-depleted. The Seqi Ultramafic Complex, as well as similar peridotite bodies in the Fiskefjord region, may thus constitute the earliest cumulates that formed during the large-scale melting event(s), which

关键词： North Atlantic Craton Archaean Dunite Platinum-group elements Ultra-depleted mantle Fiskefjord

Atomic-resolution characterization on the structure of strontium doped barium titanate nanoparticles

在线全文

学校读者我要写书评

暂无评论

Nano Research 2021年第12期14卷 4802-4807页

作者： Haoyu Jiang Jizhen Qi Dongchang Wu Wei Lu Jiahui Qian Haifeng Qu Yixiao Zhang Pei Liu Xi Liu Liwei Chen In-situ Center for Physical Sciences School of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai200240China i-Lab CAS Center for Excellence in Nanoscience Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO)Chinese Academy of SciencesSuzhou215123China Suzhou Bao Shun Mei Technology Co. Ltd.Room 305Building 1199 Jinji Lake AvenueSuzhou Industrial ParkSuzhou215123China DTU Nanolab Technical University of DenmarkFysikvejBuilding 3072800LyngbyDenmark Shanghai Nanoport Thermo Fisher Scientific Building A2517 Jinke RoadPudong DistrictShanghai201203China

Ferroelectric barium titanate nanoparticles(BTO NPs)may play critical roles in miniaturized passive electronic devices such as multi-layered ceramic *** increasing experimental and theoretical understandings on the structure of BTO and doped BTO have been developed over the past decade,the majority of the investigation was carried out in thin-film materials;therefore,the doping effect on nanoparticles remains ***,doping-induced local composition and structure fluctuation across single nanoparticles have yet to be *** this work,we use electron microscopy-based techniques including high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),integrated differential phase contrast(iDPC)-STEM,and energy dispersive X-ray spectroscopy(EDX)mapping to reveal atomically resolved chemical and crystal structure of BTO and strontium doped BTO *** X-ray diffraction(PXRD)results indicate that the increasing strontium doping causes a structural transition from tetragonal to cubic phase,but the microscopic data validate substantial compositional and microstructural inhomogeneities in strontium doped BTO *** work provides new insights into the structure of doped BTO NPs and will facilitate the materials design for next-generation high-density nano-dielectric devices.

关键词： barium titanate nanoparticles doping effect structural transition high-angle annular dark-field scanning transmission electron microscopy integrated differential phase contrast