Approaching quantitative optical diffraction analysis of crystal lattices in opal films

2008 ◽  
Author(s):  
W. Khunsin ◽  
C. M. Sotomayor Torres ◽  
S. G. Romanov
Keyword(s):  
Diffraction Analysis ◽  
Optical Diffraction ◽  
Crystal Lattices

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

Optical Diffraction Analysis of Petrographic Thin Sections

Science ◽  
1974 ◽  
Vol 186 (4160) ◽  
pp. 234-239 ◽  
Author(s):  
P. C. Power ◽  
H. J. PincuS
Keyword(s):  
Diffraction Analysis ◽  
Optical Diffraction ◽  
Thin Sections

Note on Paper 'Optical Diffraction Analysis for Estimating Foliage Angle Distribution in Grassland Canopies', by J. A. Smith and J. K. Berry.

1980 ◽  
Vol 28 (4) ◽  
pp. 495
Author(s):  
ARG Lang
Keyword(s):  
Angular Distribution ◽  
Diffraction Analysis ◽  
Probability Density ◽  
Inclination Angle ◽  
Leaf Length ◽  
Optical Diffraction ◽  
Angle Distribution

It is shown that a technique previously described for analysing foliage angular distribution in grassland canopies is not well based theoretically because it does not give exact measures of the probability density of longitudinal leaf length with respect to inclination angle.

The assembly of ribbon-shaped structures in low ionic strength extracts obtained from vertebrate smooth muscle

1973 ◽  
Vol 265 (867) ◽  
pp. 203-212 ◽  
Keyword(s):  
Smooth Muscle ◽  
Ionic Strength ◽  
Diffraction Analysis ◽  
Average Diameter ◽  
Smooth Muscle Myosin ◽  
Optical Diffraction ◽  
The Core ◽  
Regular Arrangement ◽  
Low Ionic Strength ◽  
Muscle Myosin

In actomyosin extracts from smooth muscle obtained at low ionic strength, an assembly of protein into long ribbon-shaped elements is observed to take place. These ribbons which range up to about 100 nm in width and up to many micrometres in length exhibit a strong repeat period of about 5.6 nm. Optical diffraction analysis shows that they possess a long repeat of 39.1 nm ± 0.4 nm. Tropomyosin purified from vertebrate smooth muscle can be induced to form the same ribbon-shaped elements. On removal of salt from solution the ribbons dissociate into fine filaments of average diameter about 8 nm which show subfilaments of about 2 to 3 nm diameter. In crude preparations the ribbons occur in solution together with myosin. If such preparations are left to stand for several days, ribbons may be found that show a visible 14 nm period which appears to arise from the presence of a regular arrangement of projections. Smooth muscle myosin alone assembles into cylindrical filaments which exhibit a regular arrangement of projections along their entire length, indicating an absence of polarity. These results indicate, as have those recently obtained from section material, that the myosin-containing component of vertebrate smooth muscle contains a protein that forms the core of the filament, which is responsible for its ribbon-like shape and which probably determines the polarity of the attached myosin molecules. It is proposed that this protein is tropomyosin.

Extension of the Optical Diffraction Analysis Technique for Estimating Forest Canopy Geometry.

1979 ◽  
Vol 27 (5) ◽  
pp. 575 ◽  
Author(s):  
DS Kimes ◽  
JA Smith ◽  
JK Berry
Keyword(s):  
Diffraction Analysis ◽  
Pinus Contorta ◽  
Forest Canopy ◽  
Optical Diffraction ◽  
Angle Distribution ◽  
Coordinate Transformations ◽  
Frequency Distributions ◽  
Analysis Technique ◽  
Inclination Angles

Optical diffraction analysis of in situ ground photographs has previously been used to estimate foliage angle distributions in grassland canopies. These canopies are typically characterized by a single component-leaves-and the foliage is highly linear in nature. In this paper, the diffraction technique is extended to a multicomponent forest canopy containing needles and branches. Additional convolution and coordinate transformations are used to estimate the branch and needle angle frequency distributions for top, middle, and base sections of two lodgepole pine (Pinus contorta) trees. The resulting distributions show that the branch inclination angles tend to increase as one proceeds to the tree tops. The needle inclination angle distribution was relatively constant for all layers, and it is believed that this distribution is characteristic of a large class of needle-bearing species.

scholarly journals An electron microscopic and optical diffraction analysis of the structure of Limulus telson muscle thick filaments.

1982 ◽  
Vol 92 (2) ◽  
pp. 443-451 ◽  
Author(s):  
R W Kensler ◽  
R J Levine
Keyword(s):  
Electron Microscopy ◽  
Diffraction Analysis ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Cross Bridges

Long, thick filaments (greater than 4.0 micrometer) rapidly and gently isolated from fresh, unstimulated Limulus muscle by an improved procedure have been examined by electron microscopy and optical diffraction. Images of negatively stained filaments appear highly periodic with a well-preserved myosin cross-bridge array. Optical diffraction patterns of the electron micrographs show a wealth of detail and are consistent with a myosin helical repeat of 43.8 nm, similar to that observed by x-ray diffraction. Analysis of the optical diffraction patterns, in conjunction with the appearance in electron micrographs of the filaments, supports a model for the filament in which the myosin cross-bridges are arranged on a four-stranded helix, with 12 cross-bridges per turn or each helix, thus giving an axial repeat every third level of cross-bridges (43.8 nm).

A D -periodic narrow filament in collagen

1974 ◽  
Vol 186 (1082) ◽  
pp. 67-74 ◽  
Keyword(s):  
Diffraction Analysis ◽  
Electron Micrographs ◽  
Optical Diffraction

Collagen may be reprecipitated as obliquely striated fibrils. The oblique striations are due to D -periodic subfibrils staggered axially by approxi­mately 9.0 nm with respect to their neighbours (Bruns, Trelstad & Gross 1973). The diameter of the subfibrils is variable. Optical diffraction analysis of the electron micrographs reveals instances of subfibrils with the D -repeat having diameter 3.7─4.0 nm. We argue that this structure is probably the five-stranded microfibril suggested by Smith (1968).

scholarly journals OPTICAL DIFFRACTION STUDIES OF CRYSTALLINE STRUCTURES IN ELECTRON MICROGRAPHS

1969 ◽  
Vol 43 (3) ◽  
pp. 442-447 ◽  
Author(s):  
Jacob E. Berger
Keyword(s):  
Molecular Weight ◽  
Diffraction Analysis ◽  
Electron Micrographs ◽  
Crystalline Material ◽  
Unit Cell ◽  
Optical Diffraction ◽  
Isolation And Purification ◽  
Crystalline Structures

Determination of the unit cell of crystalline particles by optical diffraction analysis of electron micrographs may establish the identity and help in approximating the molecular weight of the substances contained in the crystal. This technique may be particularly helpful when isolation and purification of the crystalline material cannot be accomplished.

Structure and function of the nematosome

1987 ◽  
Vol 87 (1) ◽  
pp. 27-44
Author(s):  
C.D. Ockleford ◽  
C.H. Nevard ◽  
I. Indans ◽  
C.J. Jones
Keyword(s):  
Nucleic Acid ◽  
Diffraction Analysis ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Structure And Function ◽  
Optical Diffraction ◽  
Serial Sectioning ◽  
Repeat Distance ◽  
Cytochemical Study ◽  
And Function

The ultrastructural morphology of human placental and mouse placental nematosomes has been investigated. The description includes a three-dimensional analysis of the shape of the organelles based on serial sectioning, measurements of the repeat distance of the subunit fibre of the organelle derived by optical diffraction analysis and the results of an ultrastructural cytochemical study designed to test whether the organelle contains nucleic acid.

Sign in / Sign up

Export Citation Format

Share Document