Nonlinear Spectral‐Imaging Study of Second‐ and Third‐Harmonic Enhancements by Surface‐Lattice Resonances

2020 ◽  
Vol 8 (8) ◽  
pp. 1901981
Author(s):  
Binglin Shen ◽  
Liwei Liu ◽  
Yanping Li ◽  
Sheng Ren ◽  
Junshuai Yan ◽  
...  
Keyword(s):  
Imaging Study ◽  
Spectral Imaging ◽  
Third Harmonic ◽  
Surface Lattice

A Near-Infrared Spectral Imaging Study of T Tau

1996 ◽  
Vol 111 ◽  
pp. 2403 ◽  
Author(s):  
T. M. Herbst ◽  
S. V. W. Beckwith ◽  
A. Glindemann ◽  
L. E. Tacconi-Garman ◽  
H. Kroker ◽  
...  
Keyword(s):  
Near Infrared ◽  
Imaging Study ◽  
Spectral Imaging ◽  
Infrared Spectral ◽  
T Tau

High resolution STEM imaging study on high Tc superconductor YBa2CuaO7-x

1988 ◽  
Vol 46 ◽  
pp. 882-883
Author(s):  
H.-J. Ou ◽  
J. M. Cowley
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Grain Boundary ◽  
Strong Field ◽  
Imaging Study ◽  
Structure Defects ◽  
High Tc ◽  
High Tc Superconductor ◽  
Diffraction Patterns ◽  
Lattice Planes

Using the dedicate VG-HB5 STEM microscope, the crystal structure of high Tc superconductor of YBa2Cu3O7-x has been studied via high resolution STEM (HRSTEM) imaging and nanobeam (∽3A) diffraction patterns. Figure 1(a) and 2(a) illustrate the HRSTEM image taken at 10' times magnification along [001] direction and [100] direction, respectively. In figure 1(a), a grain boundary with strong field contrast is seen between two crystal regions A and B. The grain boundary appears to be parallel to a (110) plane, although it is not possible to determine [100] and [001] axes as it is in other regions which contain twin planes [3]. Following the horizontal lattice lines, from left to right across the grain boundary, a lattice bending of ∽4° is noticed. Three extra lattice planes, indicated by arrows, were found to terminate at the grain boundary and form dislocations. It is believed that due to different chemical composition, such structure defects occur during crystal growth. No bending is observed along the vertical lattice lines.

Observations of Frozen-Hydrated Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 504-505
Author(s):  
D. Chrétien ◽  
D. Job ◽  
R.H. Wade
Keyword(s):  
Fourier Transforms ◽  
Structural Complexity ◽  
Image Contrast ◽  
Phase Behaviour ◽  
Experimental Conditions ◽  
Thin Sections ◽  
Surface Lattice ◽  
Cilia And Flagella ◽  
Outstanding Question

Microtubules are filamentary structures found in the cytoplasm of eukaryotic cells, where, together with actin and intermediate filaments, they form the components of the cytoskeleton. They have many functions and show various levels of structural complexity as witnessed by the singlet, doublet and triplet structures involved in the architecture of centrioles, basal bodies, cilia and flagella. The accepted microtubule model consists of a 25 nm diameter hollow tube with a wall made up of 13 paraxial protofilaments (pf). Each pf is a string of aligned tubulin dimers. Some results have suggested that the pfs follow a superhelix. To understand how microtubules function in the cell an accurate model of the surface lattice is one of the requirements. For example the 9x2 architecture of the axoneme will depend on the organisation of its component microtubules. We should also note that microtubules with different numbers of pfs have been observed in thin sections of cellular and of in-vitro material. An outstanding question is how does the surface lattice adjust to these different pf numbers?We have been using cryo-electron microscopy of frozen-hydrated samples to study in-vitro assembled microtubules. The experimental conditions are described in detail in this reference. The results obtained in conjunction with thin sections of similar specimens and with axoneme outer doublet fragments have already allowed us to characterise the image contrast of 13, 14 and 15 pf microtubules on the basis of the measured image widths, of the the image contrast symmetry and of the amplitude and phase behaviour along the equator in the computed Fourier transforms. The contrast variations along individual microtubule images can be interpreted in terms of the geometry of the microtubule surface lattice. We can extend these results and make some reasonable predictions about the probable surface lattices in the case of other pf numbers, see Table 1. Figure 1 shows observed images with which these predictions can be compared.

Alterations in regional decreased cerebral blood flow in patients with irritable bowel syndrome-A PET imaging study

2001 ◽  
Vol 120 (5) ◽  
pp. A637-A637
Author(s):  
Y RINGEL ◽  
D DROSSMAN ◽  
T TURKINGTON ◽  
B BRADSHAW ◽  
R COLEMAN ◽  
...  
Keyword(s):  
Blood Flow ◽  
Irritable Bowel Syndrome ◽  
Cerebral Blood Flow ◽  
Pet Imaging ◽  
Imaging Study ◽  
Irritable Bowel
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