Investigating Membrane-Mediated Antimicrobial Peptide Interactions with Synchrotron Radiation Far-Infrared Spectroscopy.

Synchrotron radiation-based Fourier transform infrared spectroscopy enables access to vibrational information from mid over far infrared to even terahertz domains. This information may prove critical for the elucidation of fundamental bio-molecular phenomena including folding-mediated innate host defence mechanisms. Antimicrobial peptides (AMPs) represent one of such phenomena.

Comparison of multiple X-ray fluorescence techniques for elemental analysis of particulate matter collected on air filters.

This work reports on qualitative and semi-quantitative elemental analysis of particulate matter (PM) collected on PTFE membrane filters, for a source apportionment study conducted in Brescia (Italy). Sampling was undertaken in a residential area where an increase in Mn emissions has been highlighted by previous studies. Filters are measured by means of X-ray Fluorescence (XRF) based techniques such as micro-XRF and grazing incidence XRF using synchrotron radiation, Mo or W excitation sources, after applying an automatized sample preparation method.

Rigorous calculations and synchrotron radiation measurements of diffraction efficiencies for tender X-ray lamellar gratings: conical versus classical diffraction.

When reflection gratings are operated at grazing incidence in the extreme off-plane configuration and the incident beam trajectory is parallel to the grooves, the diffraction into the first order can be more efficient than in the classical orientation. This situation is referred to as the conical diffraction case. In the classical configuration the grooves are perpendicular to the incident beam and thus an efficiency-reducing shadowing effect will be observed at very grazing angles.

Morphological and Functional Modifications of Optical Thin Films for Space Applications Irradiated with Low-Energy Helium Ions.

Future space missions will operate in increasingly hostile environments, such as those in low-perihelion solar orbits and Jovian magnetosphere. This exploration involves the selection of optical materials and components resistant to the environmental agents. The conditions in space are reproduced on ground through the use of ion accelerators.

On amplitude beam splitting of tender X-rays (2-8 keV photon energy) using conical diffraction from reflection gratings with laminar profile.

Conical diffraction is obtained when a radiation beam impinges onto a periodically ruled surface structure parallel or almost parallel to the ruling. In this condition the incident intensity is diffracted through an arc, away from the plane of incidence. The diffracted intensity thus lies on a cone, which leads to the name `conical diffraction'.

On symmetric X-ray beam splitting with high efficiency by use of reflection gratings with rectangular profile in the extreme off-plane configuration.

In order to be reflected or diffracted off a surface structure soft X-rays and hard X-rays need to impinge at grazing angles of incidence onto the surface. In case of a reflection grating of highly symmetric structure with rectangular groove profile these grooves can be oriented parallel to the beam trajectory. In such a symmetric situation the distribution of the diffracted intensity with respect to the plane of incidence is then expected to be symmetric.

Qualifying label components for effective biosensing using advanced high-throughput SEIRA methodology.

The need for technological progress in bio-diagnostic assays of high complexity requires both fundamental research and constructing efforts on nano-scaled assay recognition elements that can provide unique selectivity and design-enhanced sensitivity features. Nanoparticle induced sensitivity enhancement and its application related to multiplexed capability Surface-Enhanced InfraRed Absorption (SEIRA) assay formats are well suitable for these purposes. The potential of diverse fluorophore-antibody conjugates, being chemisorbed onto low-cost gold nanoparticulate SEIRA substrates, has been explored with respect to their spectral discriminability.

Relevance for food sciences of quantitative spatially resolved element profile investigations in wheat (Triticum aestivum) grain.

Bulk element concentrations of whole grain and element spatial distributions at the tissue level were investigated in wheat (Triticum aestivum) grain grown in Zn-enriched soil. Inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry were used for bulk analysis, whereas micro-proton-induced X-ray emission was used to resolve the two-dimensional localization of the elements. Soil Zn application did not significantly affect the grain yield, but did significantly increase the grain Ca, Fe and Zn concentrations, and decrease the grain Na, P and Mo concentrations; bulk Mg, S, K, Mn, Cu, Cd and Pb concentrations remained unchanged.

Beeswax as dental filling on a neolithic human tooth.

Evidence of prehistoric dentistry has been limited to a few cases, the most ancient dating back to the Neolithic. Here we report a 6500-year-old human mandible from Slovenia whose left canine crown bears the traces of a filling with beeswax. The use of different analytical techniques, including synchrotron radiation computed micro-tomography (micro-CT), Accelerator Mass Spectrometry (AMS) radiocarbon dating, Infrared (IR) Spectroscopy and Scanning Electron Microscopy (SEM), has shown that the exposed area of dentine resulting from occlusal wear and the upper part of a vertical crack affecting enamel and dentin tissues were filled with beeswax shortly before or after the individual's death.

New insights into globoids of protein storage vacuoles in wheat aleurone using synchrotron soft X-ray microscopy.

Mature developed seeds are physiologically and biochemically committed to store nutrients, principally as starch, protein, oils, and minerals. The composition and distribution of elements inside the aleurone cell layer reflect their biogenesis, structural characteristics, and physiological functions. It is therefore of primary importance to understand the mechanisms underlying metal ion accumulation, distribution, storage, and bioavailability in aleurone subcellular organelles for seed fortification purposes.

Synchrotron FTIR micro-spectroscopy study of the rat hippocampal formation after pilocarpine-evoked seizures.

In the present work, synchrotron radiation Fourier transform infrared (SRFTIR) micro-spectroscopy and imaging were used for topographic and semi-quantitative biochemical analysis of rat brain tissue in cases of pilocarpine-induced epilepsy. The tissue samples were analyzed with a beam defined by small apertures and spatial resolution steps of 10 microm which allowed us to probe the selected cellular layers of hippocampal formation. Raster scanning of the samples has generated 2D chemical cartographies revealing the distribution of proteins, lipids and nucleic acids.

Low-energy X-ray fluorescence microscopy opening new opportunities for bio-related research.

Biological systems are unique matter with very complex morphology and highly heterogeneous chemical composition dominated by light elements. Discriminating qualitatively at the sub-micrometer level the lateral distribution of constituent elements, and correlating it to the sub-cellular biological structure, continues to be a challenge. The low-energy X-ray fluorescence microspectroscopy, recently implemented in TwinMic scanning transmission mode, has opened up new opportunities for mapping the distribution of the light elements, complemented by morphology information provided by simultaneous acquisition of absorption and phase contrast images.

Imaging with spectroscopic micro-analysis using synchrotron radiation.

Recent developments of element-specific microscopy techniques using synchrotron radiation are opening new opportunities for the analytical investigation of various heterogeneous materials. This article provides a general description of the operational principles of different microscopes allowing chemical and structural imaging combined with micro-spot spectroscopic analysis. Several selected examples are used to illustrate the potential of the synchrotron-based methods in terms of imaging and chemical sensitivity for identification of spatial variations in the composition of morphologically complex and nano-structured inorganic and organic materials, including biological samples.

Ion exchanges in apatites for biomedical application.

The modification of the composition of apatite materials can be made by several processes corresponding to ion exchange reactions which can conveniently be adapted to current coatings and ceramics and are an alternative to setting up of new synthesis methods. In addition to high temperature thermal treatments, which can partly or almost totally replace the monovalent OH- anion of stoichiometric hydroxyapatite by any halogen ion or carbonate, aqueous processes corresponding to dissolution-reprecipitation reactions have also been proposed and used. However, the most interesting possibilities are provided by aqueous ion exchange reactions involving nanocrystalline apatites.

Apatite-mediated actin dynamics in resorbing osteoclasts.

The actin cytoskeleton is essential for osteoclasts main function, bone resorption. Two different organizations of actin have been described in osteoclasts, the podosomes belt corresponding to numerous F-actin columns arranged at the cell periphery, and the sealing zone defined as a unique large band of actin. To compare the role of these two different actin organizations, we imaged osteoclasts on various substrata: glass, dentin, and apatite.

Poorly crystalline apatites: evolution and maturation in vitro and in vivo.

Poorly crystalline apatites (PCA) are the major mineral component of mineralized tissues in vertebrates. Their physical-chemical properties are, however, not very well known due to their relative instability and the difficulties to characterize nanocrystalline compounds. Several studies using spectroscopic techniques (Fourier transform infrared [FTIR]; 31P nuclear magnetic resonance [NMR]) have demonstrated the existence, both in precipitated and biological PCA, of labile non-apatitic environments of the mineral ions.