Selective chemical mapping of coal microheterogeneity by scanning transmission x-ray microscopy

1994 ◽  
Vol 8 (1) ◽  
pp. 151-154 ◽  
Author(s):  
Robert E. Botto ◽  
George D. Cody ◽  
Janos Kirz ◽  
Harald Ade ◽  
Sutinder Behal ◽  
...  
Keyword(s):  
Chemical Mapping ◽  
X Ray ◽  
Scanning Transmission ◽  
Selective Chemical

scholarly journals Chemical Mapping of Polymer Microstructure Using Soft X-ray Spectromicroscopy

2005 ◽  
Vol 58 (6) ◽  
pp. 423 ◽  
Author(s):  
Adam P. Hitchcock ◽  
Harald D. H. Stöver ◽  
Lisa M. Croll ◽  
Ronald F. Childs
Keyword(s):  
Protein Interactions ◽  
Polymer Surfaces ◽  
Chemical Mapping ◽  
Polymer Microstructure ◽  
X Ray ◽  
Potential Control ◽  
Sample Data ◽  
Scanning Transmission ◽  
X Ray Absorption ◽  
Conducting Polymer Films

Recently, synchrotron-based soft X-ray spectromicroscopy techniques have been applied to studies of polymer microstructure at the ~50 nm spatial scale. Functional group based chemical speciation and quantitative mapping is provided by near edge X-ray absorption fine structure spectral (NEXAFS) contrast. The techniques, sample data, and analysis methods of scanning transmission X-ray microscopy (STXM) and X-ray photoemission electron microscopy (X-PEEM) are outlined. The capabilities of STXM are illustrated by results from recent studies of (a) controlled release microcapsules and microspheres, (b) microcapsules being developed for gene therapy applications, (c) conducting polymer films studied in the presence of electrolyte and under potential control, and (d) studies of protein interactions with patterned polymer surfaces. In the latter area, the capabilities of STXM and X-PEEM are compared directly.

scholarly journals Chemical mapping of polymer photoresists by scanning transmission x-ray microscopy

2005 ◽  
Vol 23 (4) ◽  
pp. 1630 ◽  
Author(s):  
Ligia Muntean ◽  
Romain Planques ◽  
A. L. D. Kilcoyne ◽  
Stephen R. Leone ◽  
Mary K. Gilles ◽  
...  
Keyword(s):  
Chemical Mapping ◽  
X Ray ◽  
Scanning Transmission

Synchrotron-Based Chemical Nano-Tomography of Microbial Cell-Mineral Aggregates in their Natural, Hydrated State

2014 ◽  
Vol 20 (2) ◽  
pp. 531-536 ◽  
Author(s):  
Gregor Schmid ◽  
Fabian Zeitvogel ◽  
Likai Hao ◽  
Pablo Ingino ◽  
Wolfgang Kuerner ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Direct Evidence ◽  
Three Dimensional ◽  
Chemical Species ◽  
Chemical Processes ◽  
Chemical Mapping ◽  
Bacterial Reduction ◽  
X Ray ◽  
Scanning Transmission ◽  
Projection Images

AbstractChemical nano-tomography of microbial cells in their natural, hydrated state provides direct evidence of metabolic and chemical processes. Cells of the nitrate-reducing Acidovorax sp. strain BoFeN1 were cultured in the presence of ferrous iron. Bacterial reduction of nitrate causes precipitation of Fe(III)-(oxyhydr)oxides in the periplasm and in direct vicinity of the cells. Nanoliter aliquots of cell-suspension were injected into custom-designed sample holders wherein polyimide membranes collapse around the cells by capillary forces. The immobilized, hydrated cells were analyzed by synchrotron-based scanning transmission X-ray microscopy in combination with angle-scan tomography. This approach provides three-dimensional (3D) maps of the chemical species in the sample by employing their intrinsic near-edge X-ray absorption properties. The cells were scanned through the focus of a monochromatic soft X-ray beam at different, chemically specific X-ray energies to acquire projection images of their corresponding X-ray absorbance. Based on these images, chemical composition maps were then calculated. Acquiring projections at different tilt angles allowed for 3D reconstruction of the chemical composition. Our approach allows for 3D chemical mapping of hydrated samples and thus provides direct evidence for the localization of metabolic and chemical processes in situ.

3d chemical mapping of toners by serial section scanning transmission X-ray microscopy

2003 ◽  
Vol 104 ◽  
pp. 509-512 ◽  
Author(s):  
A. P. Hitchcock ◽  
T. Araki ◽  
H. Ikeura-Sekiguchi ◽  
N. Iwata ◽  
K. Tani
Keyword(s):  
Serial Section ◽  
Chemical Mapping ◽  
X Ray ◽  
Scanning Transmission

Three-dimensional chemical mapping by scanning transmission X-ray spectromicroscopy

2007 ◽  
Vol 14 (5) ◽  
pp. 395-402 ◽  
Author(s):  
Göran A. Johansson ◽  
Tolek Tyliszczak ◽  
Gary E. Mitchell ◽  
Melinda H. Keefe ◽  
Adam P. Hitchcock
Keyword(s):  
Three Dimensional ◽  
Chemical Mapping ◽  
X Ray ◽  
Scanning Transmission

3D Chemical Mapping of PEM Fuel Cell Cathodes by Scanning Transmission Soft X-ray SpectroTomography

2013 ◽  
Vol 50 (2) ◽  
pp. 361-368 ◽  
Author(s):  
V. Berejnov ◽  
D. Susac ◽  
J. Stumper ◽  
A. P. Hitchcock
Keyword(s):  
Fuel Cell ◽  
Pem Fuel Cell ◽  
Chemical Mapping ◽  
X Ray ◽  
Fuel Cell Cathodes ◽  
Scanning Transmission ◽  
Cell Cathodes

scholarly journals Analysis of Cr(VI) Bioremediation by Citrobacter freundii Using Synchrotron Soft X-ray Scanning Transmission X-ray Microscopy

2021 ◽  
Vol 5 (4) ◽  
pp. 28
Author(s):  
Amith G. Anil ◽  
Sufal Swaraj ◽  
Sankaran Subramanian ◽  
Praveen C. Ramamurthy
Keyword(s):  
Chemical Speciation ◽  
Time Lapse ◽  
Gram Negative Bacteria ◽  
Citrobacter Freundii ◽  
Chemical Mapping ◽  
X Ray ◽  
Biosorption Process ◽  
Scanning Transmission ◽  
X Ray Absorption ◽  
Absorption Features

Scanning transmission X-ray microscopy (STXM) was utilized for analysing the bioremediation of Cr(VI) by Citrobacter freundii, a species of gram-negative bacteria. The biosorption and bioreduction processes were analysed by the chemical mapping of cells biosorbed at different concentrations of Cr(VI). STXM spectromicroscopy images were recorded at O K-edge and Cr L-edge. A thorough analysis of the X-ray absorption features corresponding to different oxidation states of Cr in the biosorbed cell indicated the coexistence of Cr(III) and Cr(VI) at higher concentrations. This signifies the presence of partially reduced Cr(VI) in addition to biosorbed Cr(VI). In addition, the Cr(III) signal is intense compared with Cr(VI) at different regions of the cell indicating excess of reduced Cr. Speciation of adsorbed Cr was analysed for the spectral features of biosorbed cell and comparison with Cr standards. Analysis of absorption onset, L3/L2 ratio and absorption fine structure concludes that adsorbed Cr is predominantly present as Cr(III) hydroxide or oxyhydroxide. The evolution of absorption features in the duration of biosorption process was also studied. These time lapse studies depict the gradual decrement in Cr(VI) signal as biosorption proceeds. A strong evidence of interaction of Cr with the cell material was also observed. The obtained results provide insights into the biosorption process and chemical speciation of Cr on the cells.

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