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The addition of compounds to scavenge the radical species produced during biological small-angle X-ray scattering (BioSAXS) experiments is a common strategy to reduce the effects of radiation damage and produce better quality data. As almost half of the experiments leading to structures deposited in the SASBDB database used scavengers, finding potent scavengers would be advantageous for many experiments. Here, four compounds, three nucleosides and one nitrogenous base, are presented which can act as very effective radical-scavenging additives and increase the critical dose by up to 20 times without altering the stability or reducing the contrast of the tested protein solutions. The efficacy of these scavengers is higher than those commonly used in the field to date, as verified for lysozyme solutions at various concentrations from 7.0 to 0.5 mg ml−1. The compounds are also very efficient at mitigating radiation damage to four proteins with molecular weights ranging from 7 to 240 kDa and pH values from 3 to 8, with the extreme case being catalase at 6.7 mg ml−1, with a scavenging factor exceeding 100. These scavengers can therefore be instrumental in expanding BioSAXS to low-molecular-weight and low-concentration protein samples that were previously inaccessible owing to poor data quality. It is also demonstrated that an increase in the critical dose in standard BioSAXS experiments leads to an increment in the retrieved information, in particular at higher angles, and thus to higher resolution of the model.

Although usually complex to handle, nanomechanical sensors are exceptional, label-free tools for monitoring molecular conformational changes, which makes them of paramount importance in understanding biomolecular interactions. Herein, a simple and inexpensive mechanical imaging approach based on low-stiffness cantilevers with structural coloration (mechanochromic cantilevers (MMC)) is demonstrated, able to monitor and quantify molecular conformational changes with similar sensitivity to the classical optical beam detection method of cantilever-based sensors (≈4.6 × 10

Quaternary GaInAsSb films alloys were grown by MOVPE technique on GaSb substrates with different growth conditions such as substrate orientation and thickness. The composition of the films determines their bandgap, and also how well they are lattice matched to the substrate. It is thus essential to determine it accurately, which is not a trivial task in this system. The composition of the samples was studied with a combination of Particle Induced Xray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS) experiments. The RBS experiments were done with a 2 MeV 4He+ or H+ ion beam, according to the thickness of the films, and were used to determine the thickness of the samples. The PIXE experiments were performed at grazing angle conditions and provided accurate elemental composition information. It was found that for thin layers (300 nm) there is a dependence of In incorporation into the matrix according to the substrate orientation, although this tendency was not found for thicker films (24m).