Neutron and Synchrotron Imaging Studies of Preservation State of Metal of Cultural Heritage Objects.

This paper analyzes the results of studies carried out at the National Research Center "Kurchatov Institute", Moscow, using the methods of neutron and X-ray synchrotron tomography from the point of view of the preservation state of metal objects. Objects damaged by corrosion and exposure to fire were the focus of this study. To identify regions of metal preservation, the diffraction contrast on grains of metal, observed in tomographic projections, was used. The simultaneous use of neutron and synchrotron imaging is shown to be a powerful tool for identification of the constituents of an object.

The XBI BioLab for life science experiments at the European XFEL.

The science of X-ray free-electron lasers (XFELs) critically depends on the performance of the X-ray laser and on the quality of the samples placed into the X-ray beam. The stability of biological samples is limited and key biomolecular transformations occur on short timescales. Experiments in biology require a support laboratory in the immediate vicinity of the beamlines. The XBI BioLab of the European XFEL (XBI denotes XFEL Biology Infrastructure) is an integrated user facility connected to the beamlines for supporting a wide range of biological experiments. The laboratory was financed and built by a collaboration between the European XFEL and the XBI User Consortium, whose members come from Finland, Germany, the Slovak Republic, Sweden and the USA, with observers from Denmark and the Russian Federation. Arranged around a central wet laboratory, the XBI BioLab provides facilities for sample preparation and scoring, laboratories for growing prokaryotic and eukaryotic cells, a Bio Safety Level 2 laboratory, sample purification and characterization facilities, a crystallization laboratory, an anaerobic laboratory, an aerosol laboratory, a vacuum laboratory for injector tests, and laboratories for optical microscopy, atomic force microscopy and electron microscopy. Here, an overview of the XBI facility is given and some of the results of the first user experiments are highlighted.

Cytochrome c Complexes with Cardiolipin Monolayer Formed under Different Surface Pressure.

The formation of the complex of cytochrome c (Cytc) with a phospholipid cardiolipin (CL) in mitochondria is a crucial event in apoptosis development. There are two viewpoints on the structure of the complex. (1) Cytc is bound on the surface of the lipid bilayer. (2) The complex is a hydrophobic nanoparticle Cytc-CL formed by Cytc molten globule, covered by CL monolayer.1 In the present work, we attempted to bridge the gap between these two structures. We investigated the interaction between Cytc and Langmuir monolayers of CL. The surface pressure increase during incorporation of Cytc into CL monolayer obeys the equation: π = π0 + Δπ∞[1 - exp(-ßt)], where ß is pseudo-first-order rate constant of Cytc binding, directly proportional to the initial Cytc concentration c0. Parameters Δπ∞ and the rate ß measured in different conditions were virtually equal for natural bovine CL and peroxidation-resistant tetraoleoyl CL in all experiments. Surface area-surface pressure isotherms of Cytc alone and in combination with a CL monolayer were similar in shape. Apparently, the protein exposes hydrophilic groups to the water phase and hydrophobic to the air or to the hydrocarbon chains of CL. The 30% ethanol dramatically accelerated the adsorption of Cytc on the water surface. The protein-lipid surface films showed, in compression-expansion cycles, that hysteresis loops were observed always when Cytc present, reproducible in repeating cycles. Taken together, our data show that when incorporated in a lipid monolayer or after adsorption on the water-air interface, Cytc undergoes conformational transition. In that, one part of the globule sphere becomes predominantly hydrophobic and the other, hydrophilic and charged ("stratified" Cytc). We hypothesize that in CL-containing bilayer membranes, Cytc incorporation into the lipid monolayer would result in membrane folding with subsequent formation of either catalytically reactive "bubbles" inside the bilayer, formed by Cytc-CL, or the appearance of hydrophilic pores. The role of lipid peroxidation catalyzed by Cytc-CL in the appearance of pores and apoptosis is also discussed.

Monochromatic computed microtomography using laboratory and synchrotron sources and X-ray fluorescence analysis for comprehensive analysis of structural changes in bones.

A combination of X-ray tomography at different wavelengths and X-ray fluorescence analysis was applied in the study of two types of bone tissue changes: prolonged presence in microgravity conditions and age-related bone growth. The proximal tail vertebrae of geckos were selected for investigation because they do not bear the supporting load in locomotion, which allows them to be considered as an independent indicator of gravitational influence. For the vertebrae of geckos no significant differences were revealed in the elemental composition of the flight samples and the synchronous control samples. In addition, the gecko bone tissue samples from the jaw apparatus, spine and shoulder girdle were measured. The dynamics of structural changes in the bone tissue growth was studied using samples of a human fetal hand. The hands of human fetuses of 11-15 weeks were studied. Autonomous zones of calcium accumulation were found not only in individual fingers but in each of the investigated phalanges. The results obtained are discussed.

Computed microtomography and X-ray fluorescence analysis for comprehensive analysis of structural changes in bone.

This paper presents the results of a comprehensive analysis of structural changes in the caudal vertebrae of Turner's thick-toed geckos by computer microtomography and X-ray fluorescence analysis. We present algorithms used for the reconstruction of tomographic images which allow to work with high noise level projections that represent typical conditions dictated by the nature of the samples. Reptiles, due to their ruggedness, small size, belonging to the amniote and a number of other valuable features, are an attractive model object for long-orbital experiments on unmanned spacecraft. Issues of possible changes in their bone tissue under the influence of spaceflight are the subject of discussions between biologists from different laboratories around the world.