PMC

(A) SMT(KCl) aggregates: X-ray diffraction (left); CR polarisation microscopy of the aggregates, scale: 1 μm (top right); electron microscopy of negatively stained aggregates, scale: 100 nm (bottom right). (B) SMT(Gly) aggregates: CR polarisation microscopy of the aggregates, scale: 1 μm (top left); electron microscopy of negatively stained aggregates, scale: 100 nm (bottom left); X-ray diffraction (right). (C) SMT(KCl) aggregates after partial disaggregation: X-ray diffraction (left), electron microscopy of negatively stained titin aggregates, scale: 100 nm (right). (D) SMT(Gly) aggregates after partial disaggregation: electron microscopy of negatively stained aggregates, scale: 100 nm (left); X-ray diffraction (right). (E) Microscopy under polarised light of a dried drop of buffer containing 0.15 M glycine-KOH, pH 7.2–7.4 and CR, scale: 100 μm. For electron microscopy, 2% aqueous uranyl acetate staining was used.

Plots of the signal-to-noise ratio SNR as a function of incident photons per pixel n¯ for our simulation set. The results at left are for the defined object “cell A”, while those at right are for “cell B” (see ). The results for both x-ray diffraction microscopy (XDM) and transmission x-ray microscopy (TXM) are shown. In each case a slope of about 1/2 is observed in the log₁₀(SNR) versus log₁₀(n¯) plot (), and for both objects the SNR for x-ray diffraction microscopy is about 7 times higher than it is for transmission x-ray microscopy. For x-ray diffraction microscopy of cell B, the SNR curve oscillates around the straight line fit. This oscillation corresponds to providing enough signal to phase data in successive Airy rings in the diffraction pattern of the overall spherical shape of cell B, as shown in .

(A) SEM Microscopy SEM 10000x 15 kV FTO-GLAS Clean, FTO-GLASS EDX Analysis (B) Microscopy SEM 10000x 15 kV FTO-GLAS-APTES with their respective diffraction in FTO- GLAS-APTES; (C). Microscopy SEM 10000x 15 kV FTO-GLASS-APTES-PDITC and Diffraction; (D). Microscopy SEM 10000x 15 kV FTO-GLAS-APTES-PDITC-DNA and diffraction.

Light microscopy versus diffraction. Structure determination by X-ray diffraction entails the use of a mathematical lens, Fourier Transformation (FT), to “focus” the scattered radiation.