A software package for the calibration and processing of powder X-ray diffraction and small-angle X-ray scattering data is presented. It provides a multitude of data processing and visualization tools as well as a command-line scripting interface for on-the-fly processing and the incorporation of complex data treatment tasks. Customizable processing chains permit the execution of many data processing steps to convert a single image or a batch of raw twodimensional data into meaningful data and one-dimensional diffractograms. The processed data files contain the full data provenance of each process applied to the data. The calibration routines can run automatically even for high energies and also for large detector tilt angles. Some of the functionalities are highlighted by specific use cases.

DAWN is a generic data analysis software platform that has been developed for use at synchrotron beamlines for data visualization and analysis. Its generic design makes it suitable for use in a range of scientific and engineering applications.

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The technique of drop coating deposition Raman (DCDR) spectroscopy has been shown to be a highly reproducible and sensitive method of obtaining Raman spectra from low concentration protein solutions. This study assesses the ability of DCDR to analyse changes in the relative protein concentrations of aqueous tertiary protein mixtures, with protein levels similar to that found in human tear fluid. The three proteins used to make the mixtures were lysozyme, lactoferrin and albumin. The combination of DCDR spectroscopy and principal components analysis is found to be sensitive enough to detect small changes in the relative protein concentrations, from very small sample volumes (1.5 microl). With certain mixtures it was found that the deposition of proteins was not homogeneous across the width of the ring, but averaging spectra taken at different positions could compensate for this. Principal components regression was able to predict the protein concentrations of test solutions with a good degree of accuracy (root-mean-square errors of prediction of 0.083, 0.112, and 0.082 mg ml(-1) or 8.3, 11.2 and 8.2% of the mean concentration value, for lysozyme, lactoferrin and albumin concentrations respectively). The results of this study suggest that DCDR spectroscopy could be a simple, fast, near-patient technique capable of assisting the diagnosis of ocular infection.

FTIR absorption micro-spectroscopy is a widely used, powerful technique for analysing biological materials. In principle it is a straightforward linear absorption spectroscopy, but it can be affected by artefacts that complicate the interpretation of the data. In this article, artefacts produced by the electric-field standing-wave (EFSW) in micro-reflection-absorption (transflection) spectroscopy are investigated. An EFSW is present at reflective metallic surfaces due to the interference of incident and reflected light. The period of this standing wave is dependent on the wavelength of the radiation and can produce non-linear changes in absorbance with increasing sample thickness (non-Beer-Lambert like behaviour). A protein micro-structure was produced as a simple experimental model for a biological cell and used to evaluate the differences between FTIR spectra collected in transmission and transflection. By varying the thickness of the protein samples, the relationship between the absorbance and sample thickness in transflection was determined, and shown to be consistent with optical interference due to the EFSW coupled with internal reflection from the sample top surface. FTIR spectral image data from MCF 7 breast adenocarcinoma cells was then analysed to determine the severity of the EFSW artefact in data from a real sample. The results from these measurements confirmed that the EFSW artefact has a profound effect on transflection spectra, and in this case the main spectral variations were related to the sample thickness rather than any biochemical differences.

The use of Raman spectroscopy to detect nano-sized diamond crystals is controversial; the origins of peaks at ϳ1150 cm −1 in chemical vapor deposition nanodiamond films and ϳ500 cm −1 in nanodiamond particles, which have both been suggested as evidence for nanophase material, remain uncertain. Many studies have produced evidence showing that the ϳ1150 cm −1 peak is in fact due to polyacetylenelike structures at grain boundaries and interfaces, but little work has been done to confirm the assignment of the ϳ500 cm −1 peak. In this paper we approach the problem from the molecular level, using Hartree-Fock theory to calculate the Raman spectra of diamond hydrocarbons, and observe the variation of the spectra with molecular size. Molecules with T d symmetry are studied, varying in size from adamantane to C 84 H 64 , an octahedral 1 nm-sized diamond crystallite. For comparison with nanodiamond thin films, the mass of the terminal hydrogen atoms were artificially increased to 100 amu, approximating the effects of matrix isolation. The calculated spectra are discussed in terms of the signals commonly observed in the Raman spectra of nanocrystalline diamond samples. This study finds no evidence for Raman active vibrations of diamond nanocrystals at either ϳ1150 cm −1 or ϳ500 cm −1 , whether hydrogen terminated or confined in a matrix. Further, it appears that the only signals produced by a nanodiamond crystal are the broadened zone-center ͑1332 cm −1 ͒ mode and low frequency ͑Ͻ100 cm −1 ͒ deformations/Lamb-type vibrations. This suggests any other peaks observed in the Raman spectra of nanocrystalline diamond are due to defects, surface structures, amorphous material, or any other nondiamond material in the sample, and should not be taken as definitive evidence of nanocrystalline diamond.

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