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  • 1
    Publication Date: 2022-10-19
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chase, A. P., Boss, E. S., Haentjens, N., Culhane, E., Roesler, C., & Karp-Boss, L. Plankton imagery data inform satellite-based estimates of diatom carbon. Geophysical Research Letters, 49(13), (2022): e2022GL098076, https://doi.org/10.1029/2022GL098076.
    Description: Estimating the biomass of phytoplankton communities via remote sensing is a key requirement for understanding global ocean ecosystems. Of particular interest is the carbon associated with diatoms given their unequivocal ecological and biogeochemical roles. Satellite-based algorithms often rely on accessory pigment proxies to define diatom biomass, despite a lack of validation against independent diatom biomass measurements. We used imaging-in-flow cytometry to quantify diatom carbon in the western North Atlantic, and compared results to those obtained from accessory pigment-based approximations. Based on this analysis, we offer a new empirical formula to estimate diatom carbon concentrations from chlorophyll a. Additionally, we developed a neural network model in which we integrated chlorophyll a and environmental information to estimate diatom carbon distributions in the western North Atlantic. The potential for improving satellite-based diatom carbon estimates by integrating environmental information into a model, compared to models that are based solely on chlorophyll a, is discussed.
    Description: Funding for this work was provided by NASA grants #NNX15AE67G and #80NSSC20M0202. A. Chase is supported by a Washington Research Foundation Postdoctoral Fellowship.
    Keywords: Diatoms ; Carbon ; Remote sensing ; Pigments ; Cell imagery
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 2
    ISSN: 0173-0835
    Keywords: Antibiotics ; Chiral separations ; Enantiomers ; Drugs ; Herbicides ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A new glycopeptide antibiotic, MDL 63,246 (Hepta-tyr), of the teicoplanin family, has been evaluated in capillary electrophoresis for the resolution of chiral compounds of pharmaceutical and environmental interest. Electrophoretic separations were carried out in a polyacrylamide-coated capillary using the partial filling-counter current mode with aqueous-organic buffers in the pH range 4-6. Experimental parameters affecting resolution, such as antibiotic concentration, buffer pH, organic modifier type and capillary temperature, were studied. The Hepta-tyr antibiotic exhibited a high enantiorecognition capability towards the studied compounds at very low concentrations (1-2 mg/mL). The optimum experimental conditions were achieved by using a buffer at pH 5 containing acetonitrile at 25°C.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 751-756 
    ISSN: 0173-0835
    Keywords: Glycopeptides ; Matrix ; Stability ; Capillary electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: High performance capillary electrophoresis (CE) of glycoprotein digests frequently reveals extensive microheterogeneity associated with specific protein glycosylation sites. The choice of the sample matrix can influence the electrophoretic migration time, peak shape and resolution, as well as the physical stability of the product glycopeptides. Acetic acid is a frequently employed sample matrix for both capillary electrophoresis and electrospray ionization-mass spectrometry (ESI-MS). Acetic acid appears to enhance the spontaneous hydrolysis of sialic acids from the nonreducing termini of glycopeptides in a time- and concentration-dependent manner, even at 5°C, as evidenced by changes in the electrophoretic mobility and ESI-MS spectra of the resulting glycopeptides. The observed parallel electrophoretic mobility changes for specific glycoforms are consistent with the induction of peptide structure with time. Asialoglycopeptide mobilities were stable in acetic acid. Electrophoretic mobilities can be stabilized with propionic acid sample matrix with no apparent structural changes observed by ESI-MS within 31 h. Migration time reproducibility was in the range of 0.1% relative standard deviation (N = 7) with excellent peak shapes and enhanced glycopeptide resolution.
    Additional Material: 4 Ill.
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  • 4
    ISSN: 0173-0835
    Keywords: Glycoprotein ; Glycopeptide ; Peptide ; Capillary electrophoresis ; Mass spectrometry ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: An evaluation of capillary zone electrophoresis-mass spectrometry (CZE-MS) as an analytical methodology for the separation and characterization of complex glycopeptides and nonglycopeptide structures has been performed. The evaluation employed endoproteinase V8 digested recombinant human erythropoietin (rHuEPO) that was further fractionated by reverse phase chromatography. The peptides were subjected to sequence analysis and evaluated by capillary electrophoresis, with or without mass detection, for peptide purity. The peptide mass determined from the sequence was then compared to the mass obtained from CZE-MS. Glycosylation sites and carbohydrate branch patterns were easily determined, site specific microheterogeneity (either O-acetylation of N-acetylneur-aminic acids or lactosamine extensions of the carbohydrate chain length) was assessed directly, glycosylation site occupancy was evaluated qualitatively, and nonglycopeptides were resolved and analyzed on-line with ease. Incomplete peptide digestion products were detected and identified by CZE-MS. Protein sequence coverage by CZE-MS was 98.2 percent complete from a single map. Offline evaluation of peptide purity by CZE greatly aided the interpretation of multiple sequence analysis and, in validating that, the CZE-MS was detecting all peptides present. All off-line CZE and on-line CZE-MS experiments employed a capillary that was dynamically coated with Polybrene in the presence of polyethylene glycol; separations were conducted in 0.67 M formic acid.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecological Applications 28 (2018): 749-760, doi: 10.1002/eap.1682.
    Description: The biodiversity and high productivity of coastal terrestrial and aquatic habitats are the foundation for important benefits to human societies around the world. These globally distributed habitats need frequent and broad systematic assessments, but field surveys only cover a small fraction of these areas. Satellite‐based sensors can repeatedly record the visible and near‐infrared reflectance spectra that contain the absorption, scattering, and fluorescence signatures of functional phytoplankton groups, colored dissolved matter, and particulate matter near the surface ocean, and of biologically structured habitats (floating and emergent vegetation, benthic habitats like coral, seagrass, and algae). These measures can be incorporated into Essential Biodiversity Variables (EBVs), including the distribution, abundance, and traits of groups of species populations, and used to evaluate habitat fragmentation. However, current and planned satellites are not designed to observe the EBVs that change rapidly with extreme tides, salinity, temperatures, storms, pollution, or physical habitat destruction over scales relevant to human activity. Making these observations requires a new generation of satellite sensors able to sample with these combined characteristics: (1) spatial resolution on the order of 30 to 100‐m pixels or smaller; (2) spectral resolution on the order of 5 nm in the visible and 10 nm in the short‐wave infrared spectrum (or at least two or more bands at 1,030, 1,240, 1,630, 2,125, and/or 2,260 nm) for atmospheric correction and aquatic and vegetation assessments; (3) radiometric quality with signal to noise ratios (SNR) above 800 (relative to signal levels typical of the open ocean), 14‐bit digitization, absolute radiometric calibration 〈2%, relative calibration of 0.2%, polarization sensitivity 〈1%, high radiometric stability and linearity, and operations designed to minimize sunglint; and (4) temporal resolution of hours to days. We refer to these combined specifications as H4 imaging. Enabling H4 imaging is vital for the conservation and management of global biodiversity and ecosystem services, including food provisioning and water security. An agile satellite in a 3‐d repeat low‐Earth orbit could sample 30‐km swath images of several hundred coastal habitats daily. Nine H4 satellites would provide weekly coverage of global coastal zones. Such satellite constellations are now feasible and are used in various applications.
    Description: National Center for Ecological Analysis and Synthesis (NCEAS); National Aeronautics and Space Administration (NASA) Grant Numbers: NNX16AQ34G, NNX14AR62A; National Ocean Partnership Program; NOAA US Integrated Ocean Observing System/IOOS Program Office; Bureau of Ocean and Energy Management Ecosystem Studies program (BOEM) Grant Number: MC15AC00006
    Keywords: Aquatic ; Coastal zone ; Ecology ; Essentail biodiversity variables ; H4 imaging ; Hyperspectral ; Remote sensing ; Vegetation ; Wetland
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 6
    Publication Date: 2022-05-26
    Description: Author Posting. © American Meteorological Society, 2014. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 31 (2014): 1410–1421, doi:10.1175/JTECH-D-13-00230.1.
    Description: Aerial images are used to quantify the concentration of fluorescent Rhodamine water tracing (WT) dye in turbid and optically deep water. Tracer releases near the shoreline of an ocean beach and near a tidal inlet were observed with a two-band multispectral camera and a pushbroom hyperspectral imager, respectively. The aerial observations are compared with near-surface in situ measurements. The ratio of upwelling radiance near the Rhodamine WT excitation and emission peaks varies linearly with the in situ dye concentrations for concentrations 〈20 ppb (r2 = 0.70 and r2 = 0.85–0.88 at the beach and inlet, respectively). The linear relationship allows for relative tracer concentration estimates without in situ calibration. The O(1 m) image pixels resolve complex flow structures on the inner shelf that transport and mix tracer.
    Description: We thank ONR and NSF for funding this work.
    Description: 2014-12-01
    Keywords: Coastal flows ; Mixing ; Transport ; Aircraft observations ; Remote sensing ; Tracers
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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