1. Small Angle X-ray Scattering
Rob Lewis
Centre for X-ray Physics and Imaging
School of Physics and Materials Engineering
Monash University

2. Bragg’s Law  d 2d sin θ = nλ or d = nλ/2sin θ
Small angles (< 5o ) give information on large structures – 1 to 100nm d 

3. SAXS Crystallography Microstructure Structure 10-11m 10-9 10-7 10-5
Elliot Gilbert ANSTO

4. Diffraction Configuration

5. SAXS Works on live wet specimens Time resolution - sub microsecond
Two main variants
Solution scattering
Protein folding
Protein ligand interactons
Fibre diffraction
Tissue analysis
Muscle operation

6. Diffraction

7. Diffraction

8. 6 models of sAPPα695 Dark indicates areas of superposition
A B and C are orthogonal views
Crystal model of N terminal domain of APP
Gralle et al Biophys J 83, 3513 (2002)

9. Collagen Axial Structure
Tropocollagen
Secreted from cell
1.5nm N
Overlap
Gap
67nm
Overlap
Gap
Overlap
Gap
Proteolytic cleavage
Procollagen N protease
Procollagen C protease
10.4nm
300nm
Cross links involve lysyl oxidase C

10. Collagen
Rat tail tendon
Camera length: 9.35m
Wavelength: 0.154nm

11. Different tissues

12. Diffracted Intensity: Trend

13. Osteochondral Autograft Transplantation OATS

14. OATS surgical technique
MARIARC MRI, University Liverpool, UK
Incorrect graft harvest and recipient socket angles, are the most common OAT surgical errors and reasons for failure.

15. Slide: S Arnotzky

16. Lamb Cartilage Study

17. Myelin Diffraction

18. Muscle diffraction Resting Contracted
shows two diffraction patterns taken form a live muscle. One whilst resting and the other at the peak of contraction.
The intensity of SR allows real movies to be taken at a molecular level of muscle as it contracts and is yielding great insight into how mucle really works
OK now to more familiar territory. Imaging