Contrasted redox-dependent structural control on Fe isotope fractionation during its adsorption onto and assimilation by heterotrophic soil bacteria.

Despite the importance of structural control on metal stable isotope fractionation in inorganic and abiotic systems, the link between metal structural changes and related isotopic fractionation during reactions with organic surfaces and live cells remains poorly established. We conducted reversible adsorption of Fe(II) and Fe(III) on the surface of exopolysaccharide (EPS)-rich and EPS-poor , and we allowed Fe intracellular uptake by growing cells. We analyzed the Fe isotopic composition of the remaining fluid and cell biomass, and compared the isotopic fractionation during adsorption and assimilation reaction with relative changes in Fe structural status between aqueous solution and bacterial cells, based on available and newly collected X-ray absorption spectroscopy (XAS) observations.

Raman amplification in the ultra-small limit of Ag nanoparticles on SiO and graphene: Size and inter-particle distance effects.

Size, shape and hot spots are crucial to optimize Raman amplification from metallic nanoparticle (NPs). The amplification from radius = 1.8 ± 0.

Efficient Heterostructures for Combined Interference and Plasmon Resonance Raman Amplification.

The detection, identification, and quantification of different types of molecules and the optical imaging of, for example, cellular processes are important challenges. Here, we present how interference-enhanced Raman scattering (IERS) in adequately designed heterostructures can provide amplification factors relevant for both detection and imaging. Calculations demonstrate that the key factor is maximizing the absolute value of the refractive indices' difference between dielectric and metal layers.

Chemical and structural characterization of copper adsorbed on mosses (Bryophyta).

The adsorption of copper on passive biomonitors (devitalized mosses Hypnum sp., Sphagnum denticulatum, Pseudoscleropodium purum and Brachythecium rutabulum) was studied under different experimental conditions such as a function of pH and Cu concentration in solution. Cu assimilation by living Physcomitrella patents was also investigated.

Environmental influence on Zn-histidine complexes under no-packing conditions.

This paper describes a combined structural analysis of the Zn-histidine complex, using two different and complementary techniques, X-ray absorption spectroscopy (XAS) and surface X-ray diffraction, paying special attention to the environmental conditions. The current procedure for investigating macromolecules consists of examining simple molecules that exhibit properties similar to those of the larger ones, whose functionality is totally related to the atomic structure. The detailed study of the bonding structure formed by zinc and histidine amino acids is motivated by the fact that this material serves as a model for metalloproteins, such as in metalloproteinase, acting as active sites in enzymatic or structural functions.