X-ray scattering by bicontinuous cubic phases

1994 ◽  
Vol 4 (2) ◽  
pp. 275-286 ◽  
Author(s):  
M. Clerc ◽  
E. Dubois-Violette
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Cubic Phases ◽  
Bicontinuous Cubic ◽  
Ray Scattering

Control and Analysis of Oriented Thin Films of Lipid Inverse Bicontinuous Cubic Phases Using Grazing Incidence Small-Angle X-ray Scattering

Langmuir ◽  
2013 ◽  
Vol 29 (31) ◽  
pp. 9874-9880 ◽  
Author(s):  
Martyn Rittman ◽  
Heinz Amenitsch ◽  
Michael Rappolt ◽  
Barbara Sartori ◽  
Benjamin M. D. O’Driscoll ◽  
...  
Keyword(s):  
Thin Films ◽  
Small Angle ◽  
Grazing Incidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Cubic Phases ◽  
Bicontinuous Cubic ◽  
Ray Scattering

Simultaneous Rheology and Small-Angle Scattering Experiments on Block Copolymer Gels and Melts in Cubic Phases

1998 ◽  
Vol 31 (6) ◽  
pp. 881-889 ◽  
Author(s):  
I. W. Hamley ◽  
J. A. Pople ◽  
A. J. Gleeson ◽  
B. U. Komanschek ◽  
E. Towns-Andrews
Keyword(s):  
Block Copolymer ◽  
Small Angle ◽  
Large Amplitude ◽  
Cubic Phase ◽  
Shear Direction ◽  
X Ray ◽  
X Ray Scattering ◽  
Cubic Phases ◽  
Bicontinuous Cubic ◽  
Ray Scattering

A new instrument for simultaneous small-angle X-ray scattering and rheology experiments on soft solids is described. This device is based on a commercial rheometer with a shear sandwich geometry in which the sample is subjected to a planar oscillatory deformation. This instrument has been used for time-resolved small-angle X-ray scattering/rheology experiments at the Synchrotron Radiation Source, Daresbury Laboratory, England. The focus has been in particular on the effect of large-amplitude shearing on the orientation of cubic phases in gels of block copolymers formed in concentrated solutions, and on the bicontinuous cubic phase of a block copolymer melt. Representative results are presented for face-centred cubic (f.c.c.) and body-centred cubic (b.c.c.) phases in gels of poly(oxyethylene)–poly(oxybutylene) diblock copolymers, and for the bicontinuous cubic `gyroid' structure in a poly-(ethylene-alt-propylene)–poly(dimethylsiloxane) di-block copolymer melt. The orientations of the micellar b.c.c. phases in the gels and the gyroid structure (belonging to the b.c.c. space group Ia\bar 3d) following large-amplitude shearing are shown to be the same,i.e.directionally oriented crystals are produced in both cases, in which (111) directions are oriented along the shear direction.

Small-Angle Neutron and X-ray Scattering from Amphiphilic Stimuli-Responsive Diamond-Type Bicontinuous Cubic Phase

2007 ◽  
Vol 129 (44) ◽  
pp. 13474-13479 ◽  
Author(s):  
Borislav Angelov ◽  
Angelina Angelova ◽  
Vasil M. Garamus ◽  
Geneviève Lebas ◽  
Sylviane Lesieur ◽  
...  
Keyword(s):  
Small Angle ◽  
Cubic Phase ◽  
Stimuli Responsive ◽  
X Ray ◽  
X Ray Scattering ◽  
Bicontinuous Cubic ◽  
Diamond Type ◽  
Ray Scattering

Molecular Packing in Double Gyroid Cubic Phases Revealed via Resonant Soft X-Ray Scattering

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
Yu Cao ◽  
Mohamed Alaasar ◽  
Asritha Nallapaneni ◽  
Mirosław Salamończyk ◽  
Peter Marinko ◽  
...  
Keyword(s):  
Molecular Packing ◽  
X Ray ◽  
X Ray Scattering ◽  
Cubic Phases ◽  
Double Gyroid ◽  
Ray Scattering

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

X-ray scattering by 1D molecular Guinier-Preston zones in ordered smectic phases

1992 ◽  
Vol 2 (6) ◽  
pp. 899-913 ◽  
Author(s):  
Patrick Davidson ◽  
Elisabeth Dubois-Violette ◽  
Anne-Marie Levelut ◽  
Brigitte Pansu
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Smectic Phases ◽  
Ray Scattering
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