Journal: Ultramicroscopy

Article Title: Application of EELS and EFTEM to the Life Sciences Enabled by the Contributions of Ondrej Krivanek

doi: 10.1016/j.ultramic.2017.01.002

Figure Lengend Snippet: STEM-EELS imaging of frozen hydrated specimens at a beam energy of 100 keV using a Gatan PEELS interfaced to a VG Microscopes HB501 STEM. (a) Low-loss spectra up to an energy loss of 30 eV from major chemical constituents of cells; these can be used to fit spectra from cryosectioned cells to give quantitative compositional information; (b) Low-dose dark-field STEM of frozen hydrated liver cryosection showing no contrast apart from deformation lines; scale bar = 1 μm; (c) Water map of hepatocytes generated by multiple least squares fitting of water and protein reference spectra at each pixel revealing: mitochondria (M), cytoplasm (C), red blood cells (R), plasma (P) and lipid droplets (L); (d) Water content histogram for 2700 pixels of cytoplasm (light bars) and 500 pixels of mitochondria (dark bars) in hepatocyte, showing approximately Gaussian peaks with half width ~5%. From S. Sun et al. [27].

Article Snippet: Other laboratories have also determined water distributions using this approach [ 28 , 29 ]. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Figure 4 caption a7 STEM-EELS imaging of frozen hydrated specimens at a beam energy of 100 keV using a Gatan PEELS interfaced to a VG Microscopes HB501 STEM. (a) Low-loss spectra up to an energy loss of 30 eV from major chemical constituents of cells; these can be used to fit spectra from cryosectioned cells to give quantitative compositional information; (b) Low-dose dark-field STEM of frozen hydrated liver cryosection showing no contrast apart from deformation lines; scale bar = 1 μm; (c) Water map of hepatocytes generated by multiple least squares fitting of water and protein reference spectra at each pixel revealing: mitochondria (M), cytoplasm (C), red blood cells (R), plasma (P) and lipid droplets (L); (d) Water content histogram for 2700 pixels of cytoplasm (light bars) and 500 pixels of mitochondria (dark bars) in hepatocyte, showing approximately Gaussian peaks with half width ~5%.

Techniques: Imaging, Generated

Journal: Ultramicroscopy

Article Title: Application of EELS and EFTEM to the Life Sciences Enabled by the Contributions of Ondrej Krivanek

doi: 10.1016/j.ultramic.2017.01.002

Figure Lengend Snippet: Spectrum-imaging of two neuronal dendrites in the vicinity of the Ca L2,3 edge, together with dark-field images (A, E) obtained using the Gatan 666 Parallel EELS attached to a VG Microscopes HB501 STEM. Background-subtracted nitrogen K-edge maps (B, F) reveal location of mitochondria and membranes of endoplasmic reticulum. Very weak signals are detected when these nitrogen maps are segmented according to compartment: endoplasmic reticulum (C, G) and mitochondria (D, H); Bars = 200 nm. Spectra at each pixel were acquired in the difference mode with a 6 eV shift to reduce noise due to channel gain variations in the photodiode array. Multiple-least-squares fit (solid curves) of filtered reference spectra for segmented spectrum-image data (circles) in endoplasmic reticulum (J) and mitochondria (K). Analysis of the Ca L2,3 edge signal showed that the ER calcium concentration was 4.9±0.4 mmol/kg dry wt., and the mitochondrial calcium concentration was 1.4±0.4 mmol/kg dry wt. From R.D. Leapman et al. [35].

Article Snippet: Other laboratories have also determined water distributions using this approach [ 28 , 29 ]. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Figure 4 caption a7 STEM-EELS imaging of frozen hydrated specimens at a beam energy of 100 keV using a Gatan PEELS interfaced to a VG Microscopes HB501 STEM. (a) Low-loss spectra up to an energy loss of 30 eV from major chemical constituents of cells; these can be used to fit spectra from cryosectioned cells to give quantitative compositional information; (b) Low-dose dark-field STEM of frozen hydrated liver cryosection showing no contrast apart from deformation lines; scale bar = 1 μm; (c) Water map of hepatocytes generated by multiple least squares fitting of water and protein reference spectra at each pixel revealing: mitochondria (M), cytoplasm (C), red blood cells (R), plasma (P) and lipid droplets (L); (d) Water content histogram for 2700 pixels of cytoplasm (light bars) and 500 pixels of mitochondria (dark bars) in hepatocyte, showing approximately Gaussian peaks with half width ~5%.

Techniques: Imaging, Concentration Assay

Journal: Ultramicroscopy

Article Title: Application of EELS and EFTEM to the Life Sciences Enabled by the Contributions of Ondrej Krivanek

doi: 10.1016/j.ultramic.2017.01.002

Figure Lengend Snippet: Application of scanning transmission electron microscope-electron energy-loss spectroscopy (STEM-EELS) to explain contrast observed in brain magnetic resonance images (MRI) in terms of iron concentrations. (a) Optical micrograph of post-mortem human visual cortex treated with Perl stain for iron, showing elevated iron in the region of the line of Gennari (arrows). (b) Corresponding MRI, also showing contrast in the line of Gennari (arrows). Image widths in (a) and (b) are the same, and asterisks indicate boundaries of region of visual cortex. (c) Phase-contrast transmission electron microscopy of unstained section in the region of the line of Gennari showing electron-dense particles. (d–f) STEM-EELS iron maps obtained from randomly selected areas of an unstained specimen in the vicinity of the line of Gennari, showing particles with high Fe content. (g) Typical EELS extracted from one of the Fe-containing particles reveals a strong Fe L2,3 edge; quantitative analysis showed that the particles contained on average 1740 ± 580 Fe atoms, consistent with the iron cores of ferritin molecules; dotted lines indicate extrapolated background intensity. From M. Fukunaga et al. [36].

Article Snippet: Other laboratories have also determined water distributions using this approach [ 28 , 29 ]. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Figure 4 caption a7 STEM-EELS imaging of frozen hydrated specimens at a beam energy of 100 keV using a Gatan PEELS interfaced to a VG Microscopes HB501 STEM. (a) Low-loss spectra up to an energy loss of 30 eV from major chemical constituents of cells; these can be used to fit spectra from cryosectioned cells to give quantitative compositional information; (b) Low-dose dark-field STEM of frozen hydrated liver cryosection showing no contrast apart from deformation lines; scale bar = 1 μm; (c) Water map of hepatocytes generated by multiple least squares fitting of water and protein reference spectra at each pixel revealing: mitochondria (M), cytoplasm (C), red blood cells (R), plasma (P) and lipid droplets (L); (d) Water content histogram for 2700 pixels of cytoplasm (light bars) and 500 pixels of mitochondria (dark bars) in hepatocyte, showing approximately Gaussian peaks with half width ~5%.

Techniques: Transmission Assay, Microscopy, Spectroscopy, Staining, Electron Microscopy

Journal: Ultramicroscopy

Article Title: Application of EELS and EFTEM to the Life Sciences Enabled by the Contributions of Ondrej Krivanek

doi: 10.1016/j.ultramic.2017.01.002

Figure Lengend Snippet: Spatially resolved element STEM-EELS analysis of hybrid silica nanoparticles containing quantum dots and coated with lipid that bind gadolinium; HAADF image of the lipid-coated nanoparticles (a); composite color map showing the location of different elements: red, blue and green indicate gadolinium (N4,5 edge), silicon (L2,3 edge) and carbon atoms (C K edge), respectively. From M.M. van Schooneveld et al. [39].

Article Snippet: Other laboratories have also determined water distributions using this approach [ 28 , 29 ]. fig ft0 fig mode=article f1 fig/graphic|fig/alternatives/graphic mode="anchored" m1 Open in a separate window Figure 4 caption a7 STEM-EELS imaging of frozen hydrated specimens at a beam energy of 100 keV using a Gatan PEELS interfaced to a VG Microscopes HB501 STEM. (a) Low-loss spectra up to an energy loss of 30 eV from major chemical constituents of cells; these can be used to fit spectra from cryosectioned cells to give quantitative compositional information; (b) Low-dose dark-field STEM of frozen hydrated liver cryosection showing no contrast apart from deformation lines; scale bar = 1 μm; (c) Water map of hepatocytes generated by multiple least squares fitting of water and protein reference spectra at each pixel revealing: mitochondria (M), cytoplasm (C), red blood cells (R), plasma (P) and lipid droplets (L); (d) Water content histogram for 2700 pixels of cytoplasm (light bars) and 500 pixels of mitochondria (dark bars) in hepatocyte, showing approximately Gaussian peaks with half width ~5%.

Techniques: