Simultaneous fast XAS/SAXS measurements in an energy-dispersive mode.

X-ray absorption spectroscopy (XAS) and small-angle X-ray scattering (SAXS) are common materials characterization tools at synchrotron radiation facilities used in many research fields. Since XAS can provide element-specific chemical states and local atomic structures and SAXS can provide nano-scale structural information, their complementary use is advantageous for a comprehensive understanding of multiscale phenomena. This paper presents a new method for simultaneous XAS/SAXS measurements with synchrotron radiation.

Periodic Elastic Motion in a Self-Assembled Monolayer under Spontaneous Oscillations of Surface Tension: Molecules in a Scrum Push Back a Marangoni Flow.

Regularly recurring phenomena are a common and important part of life. Such rhythmic behaviors are often seen in nonliving systems under far-from-equilibrium conditions. The study of simple nonliving systems provides clues for improving our understanding of the origin of biological rhythms.

Initial Conformation of Adsorbed Proteins at an Air-Water Interface.

We present the results of time-resolved X-ray reflectivity measurements carried out to investigate the early stage of protein adsorption and deformation at an air-water interface. Three globular proteins [lysozyme, myoglobin, and bovine serum albumin (BSA)] were studied, and we observed that the proteins adsorbed at the air-water interface initially possessed a thinner conformation than their native structures. The degree of deformation increased in the order myoglobin < lysozyme < BSA, which was inconsistent with the order of molecular flexibility.

A quick convergent-beam laboratory X-ray reflectometer using a simultaneous multiple-angle dispersive geometry.

An X-ray reflectometer using a laboratory X-ray source for quick measurements of the specular X-ray reflectivity curve is presented. It uses a bent-twisted crystal to monochromatize and focus the diverging X-rays (Cu α) from a laboratory point source onto the sample. The reflected X-rays are recorded with a two-dimensional detector.

Real-time investigation of protein unfolding at an air-water interface at the 1 s time scale.

Protein unfolding at an air-water interface has been demonstrated such that the X-ray reflectivity can be measured with an acquisition time of 1 s using a recently developed simultaneous multiple-angle-wavelength-dispersive X-ray reflectometer. This has enabled the electron density profile of the adsorbed protein molecules to be obtained in real time. A globular protein, lysozyme, adsorbed at the air-water interface is found to unfold into a flat shape within 1 s.

A simultaneous multiple angle-wavelength dispersive X-ray reflectometer using a bent-twisted polychromator crystal.

An X-ray reflectometer has been developed, which can simultaneously measure the whole specular X-ray reflectivity curve with no need for rotation of the sample, detector or monochromator crystal during the measurement. A bent-twisted crystal polychromator is used to realise a convergent X-ray beam which has continuously varying energy E (wavelength λ) and glancing angle α to the sample surface as a function of horizontal direction. This convergent beam is reflected in the vertical direction by the sample placed horizontally at the focus and then diverges horizontally and vertically.