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  • 1
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    Quantitative high dynamic range beam profiling for fluorescence microscopy (2014)
    American Institute of Physics (AIP)
    Details
    Publication Date: 2014-10-30
    Description: Modern developmental biology relies on optically sectioning fluorescence microscope techniques to produce non-destructive in vivo images of developing specimens at high resolution in three dimensions. As optimal performance of these techniques is reliant on the three-dimensional (3D) intensity profile of the illumination employed, the ability to directly record and analyze these profiles is of great use to the fluorescence microscopist or instrument builder. Though excitation beam profiles can be measured indirectly using a sample of fluorescent beads and recording the emission along the microscope detection path, we demonstrate an alternative approach where a miniature camera sensor is used directly within the illumination beam. Measurements taken using our approach are solely concerned with the illumination optics as the detection optics are not involved. We present a miniature beam profiling device and high dynamic range flux reconstruction algorithm that together are capable of accurately reproducing quantitative 3D flux maps over a large focal volume. Performance of this beam profiling system is verified within an optical test bench and demonstrated for fluorescence microscopy by profiling the low NA illumination beam of a single plane illumination microscope. The generality and success of this approach showcases a widely flexible beam amplitude diagnostic tool for use within the life sciences.
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Published by American Institute of Physics (AIP)
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  • 2
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    Fossil steroids record the appearance of Demospongiae during the Cryogenian period (2009)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2009-02-06
    Description: The Neoproterozoic era (1,000-542 Myr ago) was an era of climatic extremes and biological evolutionary developments culminating in the emergence of animals (Metazoa) and new ecosystems. Here we show that abundant sedimentary 24-isopropylcholestanes, the hydrocarbon remains of C(30) sterols produced by marine demosponges, record the presence of Metazoa in the geological record before the end of the Marinoan glaciation ( approximately 635 Myr ago). These sterane biomarkers are abundant in all formations of the Huqf Supergroup, South Oman Salt Basin, and, based on a new high-precision geochronology, constitute a continuous 100-Myr-long chemical fossil record of demosponges through the terminal Neoproterozoic and into the Early Cambrian epoch. The demosponge steranes occur in strata that underlie the Marinoan cap carbonate (〉635 Myr ago). They currently represent the oldest evidence for animals in the fossil record, and are evidence for animals pre-dating the termination of the Marinoan glaciation. This suggests that shallow shelf waters in some late Cryogenian ocean basins (〉635 Myr ago) contained dissolved oxygen in concentrations sufficient to support basal metazoan life at least 100 Myr before the rapid diversification of bilaterians during the Cambrian explosion. Biomarker analysis has yet to reveal any convincing evidence for ancient sponges pre-dating the first globally extensive Neoproterozoic glacial episode (the Sturtian, approximately 713 Myr ago in Oman).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Love, Gordon D -- Grosjean, Emmanuelle -- Stalvies, Charlotte -- Fike, David A -- Grotzinger, John P -- Bradley, Alexander S -- Kelly, Amy E -- Bhatia, Maya -- Meredith, William -- Snape, Colin E -- Bowring, Samuel A -- Condon, Daniel J -- Summons, Roger E -- England -- Nature. 2009 Feb 5;457(7230):718-21. doi: 10.1038/nature07673.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of California, Riverside, California 92521, USA. glove@ucr.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19194449" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arabia ; *Biological Evolution ; Biomarkers/analysis/chemistry ; Cholestanes/*analysis/*chemistry/isolation & purification ; *Fossils ; Gas Chromatography-Mass Spectrometry ; Geologic Sediments/*chemistry ; History, Ancient ; Hydrocarbons/analysis/chemistry ; Ice Cover ; Oceans and Seas ; Oxygen/analysis ; Porifera/*physiology ; Seawater/chemistry
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 3
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    A stratified redox model for the Ediacaran ocean (2010)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2010-02-13
    Description: The Ediacaran Period (635 to 542 million years ago) was a time of fundamental environmental and evolutionary change, culminating in the first appearance of macroscopic animals. Here, we present a detailed spatial and temporal record of Ediacaran ocean chemistry for the Doushantuo Formation in the Nanhua Basin, South China. We find evidence for a metastable zone of euxinic (anoxic and sulfidic) waters impinging on the continental shelf and sandwiched within ferruginous [Fe(II)-enriched] deep waters. A stratified ocean with coeval oxic, sulfidic, and ferruginous zones, favored by overall low oceanic sulfate concentrations, was maintained dynamically throughout the Ediacaran Period. Our model reconciles seemingly conflicting geochemical redox conditions proposed previously for Ediacaran deep oceans and helps to explain the patchy temporal record of early metazoan fossils.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Li, Chao -- Love, Gordon D -- Lyons, Timothy W -- Fike, David A -- Sessions, Alex L -- Chu, Xuelei -- New York, N.Y. -- Science. 2010 Apr 2;328(5974):80-3. doi: 10.1126/science.1182369. Epub 2010 Feb 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of California, Riverside, CA 92521, USA. chaoli@ucr.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20150442" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Biological Evolution ; Carbonates/analysis ; China ; Ferrous Compounds/analysis ; *Fossils ; Geologic Sediments/*chemistry ; Hydrogen Sulfide ; Iron ; Oceans and Seas ; Oxidation-Reduction ; Oxygen/*analysis ; Seawater/*chemistry ; Sulfates/analysis
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 4
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    Photic zone euxinia during the Permian-triassic superanoxic event (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-01-22
    Description: Carbon and sulfur isotopic data, together with biomarker and iron speciation analyses of the Hovea-3 core that was drilled in the Perth Basin, Western Australia, indicate that euxinic conditions prevailed in the paleowater column during the Permian-Triassic superanoxic event. Biomarkers diagnostic for anoxygenic photosynthesis by Chlorobiaceae are particularly abundant at the boundary and into the Early Triassic. Similar conditions prevailed in the contemporaneous seas off South China. Our evidence for widespread photiczone euxinic conditions suggests that sulfide toxicity was a driver of the extinction and a factor in the protracted recovery.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Grice, Kliti -- Cao, Changqun -- Love, Gordon D -- Bottcher, Michael E -- Twitchett, Richard J -- Grosjean, Emmanuelle -- Summons, Roger E -- Turgeon, Steven C -- Dunning, William -- Jin, Yugan -- New York, N.Y. -- Science. 2005 Feb 4;307(5710):706-9. Epub 2005 Jan 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Curtin University of Technology, Perth, Australia. K.Grice@curtin.edu.au〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15661975" target="_blank"〉PubMed〈/a〉
    Keywords: Anaerobiosis ; Animals ; Carbon Isotopes/analysis ; Chlorobi/*physiology ; *Ecosystem ; Geologic Sediments/chemistry/microbiology ; Invertebrates/physiology ; Iron/analysis ; Isotopes ; Light ; Oceans and Seas ; Oxidation-Reduction ; Photosynthesis ; Seawater/*chemistry ; Sulfides/analysis/toxicity ; Sulfur Isotopes/analysis ; Time ; Western Australia
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 5
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    Widespread iron-rich conditions in the mid-Proterozoic ocean (2011)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2011-09-09
    Description: The chemical composition of the ocean changed markedly with the oxidation of the Earth's surface, and this process has profoundly influenced the evolutionary and ecological history of life. The early Earth was characterized by a reducing ocean-atmosphere system, whereas the Phanerozoic eon (less than 542 million years ago) is known for a stable and oxygenated biosphere conducive to the radiation of animals. The redox characteristics of surface environments during Earth's middle age (1.8-1 billion years ago) are less well known, but it is generally assumed that the mid-Proterozoic was home to a globally sulphidic (euxinic) deep ocean. Here we present iron data from a suite of mid-Proterozoic marine mudstones. Contrary to the popular model, our results indicate that ferruginous (anoxic and Fe(2+)-rich) conditions were both spatially and temporally extensive across diverse palaeogeographic settings in the mid-Proterozoic ocean, inviting new models for the temporal distribution of iron formations and the availability of bioessential trace elements during a critical window for eukaryotic evolution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Planavsky, Noah J -- McGoldrick, Peter -- Scott, Clinton T -- Li, Chao -- Reinhard, Christopher T -- Kelly, Amy E -- Chu, Xuelei -- Bekker, Andrey -- Love, Gordon D -- Lyons, Timothy W -- England -- Nature. 2011 Sep 7;477(7365):448-51. doi: 10.1038/nature10327.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Earth Sciences, University of California, Riverside, California 92521, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21900895" target="_blank"〉PubMed〈/a〉
    Keywords: Biological Evolution ; Geologic Sediments/chemistry ; History, Ancient ; Iron/*analysis/chemistry ; Oceans and Seas ; Seawater/*chemistry ; Sulfur/analysis/chemistry ; Sulfur Isotopes ; Time Factors
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 6
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    Microbially mediated iron reduction in the methanic zone of marine sediments from the western Argentine Basin (2011)
    In:  EPIC3Goldschmidt Conference, Prague, August 2011.
    Details
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 7
    Electronic Resource
    Electronic Resource
    Single-pulse excitation carbon-13 NMR measurements on the Argonne premium coal samples (1992)
    s.l. : American Chemical Society
    Energy & fuels 6 (1992), S. 598-602 
    Details
    ISSN: 1520-5029
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ef00035a009
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of nonprotonated aromatic carbon concentrations in coals by single pulse excitation carbon-13 NMR (1993)
    s.l. : American Chemical Society
    Energy & fuels 7 (1993), S. 639-644 
    Details
    ISSN: 1520-5029
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ef00041a012
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  • 9
    Electronic Resource
    Electronic Resource
    Mechanisms of char production from oxidized cellulose (1995)
    Springer
    Journal of materials science 30 (1995), S. 596-600 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A multi-technique approach, incorporating nuclear magnetic resonance (NMR), elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis and surface area determination, has been used to investigate the formation of chars by oxidized cellulose. It was found that oxidation of the cellulose tends to increase the surface area of the resulting char. NMR, elemental analysis and DSC show how cellulose oxidation tends to increase aromaticity and cross-linking. This, in turn, decreases diffusion rates of volatiles out of the oxidized cellulose during pyrolysis, giving denser carbons and higher BET surface areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00356316
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of the aromatic lignin content in oak wood by quantitative solid state 13C-NMR (1992)
    New York : Wiley-Blackwell
    Biopolymers 32 (1992), S. 1187-1192 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problems concerning quantification with cross polarization (CP) and high-field 13C-nmr measurements has meant that, for ligno-cellulosic plant materials, aromatic carbons in lignins are often discriminated against. In this study, the aromatic lignin content of an American red oak sample has been determined at the relatively low field strength of 25 MHz to obviate problems with spinning side bands using both CP and Bloch decay or single pulse excitation (SPE), a more time-consuming acquisition technique but that is, in many cases, considerably more quantitative than CP. The value of 14 mole % carbon from SPE is in close agreement with that of 15% derived from elemental analysis and the Klason lignin content. Although virtually all of the carbon was observed by both SPE and CP, the latter significantly underestimated the aromatic content at contact times less than 1.5 ms and thus longer times should be used for reliable quantification. The quaternary carbon content was estimated as 11 mole % carbon by combining dipolar dephasing with SPE and CP. © 1992 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360320908
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