Effects of radiation damage and inelastic scattering on single-particle imaging of hydrated proteins with an X-ray Free-Electron Laser

We present a computational case study of X-ray single-particle imaging of hydrated proteins on an example of 2-Nitrogenase–Iron protein covered with water layers of various thickness, using a start-to-end simulation platform and experimental parameters of the SPB/SFX instrument at the European X-ray Free-Electron Laser facility. The simulations identify an optimal thickness of the water layer at which the effective resolution for imaging the hydrated sample becomes significantly higher than for the non-hydrated sample. This effect is lost when the water layer becomes too thick. Even though the detailed results presented pertain to the specific sample studied, the trends which we identify should also hold in a general case. We expect these findings will guide future single-particle imaging experiments using hydrated proteins.

First find of a potentially new mineral, Na-dominant at M 2-site eudialyte analogue: crystal structure and significance as a marker of ultraagpaitic environment

A potentially new mineral, M2Na-dominant analogue of eudialyte from the Khibiny alkaline massif, was investigated using the methods of electron probe microanalysis, X-ray diffraction, and IR spectroscopy. The crystal structure was refined to R = 5.7% in the anisotropic approximation of atomic displacements using 2577 independent reflections with F > 3(F). The unit-cell parameters are: a = 14.277(1), c = 30.400(1) Å, V = 5328.7(1) Å3; the space group is R-3m. The idealized formula of the mineral is (Z = 3): Na14Ca6Zr3[Na2(Fe,Mn)][Si26O72](OH)2(H2O1.0Cl0.6S2-0.5)(OH,H2O)2.5. Distribution of cations in the M2 micro-region is established: Fe in the flat-square coordination, Mn in the square pyramid and Na in the seven-vertex polyhedron. A comparative analysis of crystal chemical features of eudialyte М2Na-analogue samples from the Khibiny-Lovozero alkaline complex and Ilimaussaq alkaline pluton, Greenland is given. The mechanism of blocky isomorphism with the replacement of IVFe2+ with VIINa in the M2 micro-region is discussed. IR spectra of the М2Na-dominant eudialyte analogue are given: essentially hydrated sample (Na,H3O,H2O)15Ca6Zr3[Na2Fe][Si26O72](OH)2Cl∙2H2O from Ilimaussaq, less hydrated М2Zr-bearing sample (Na,H3O)13(Ca4Mn2)Zr3(Na2Zr)[Si26O72](OH)2Cl∙H2O from Lovozero and low-hydrated sample Na14Ca6Zr3[Na2(Fe,Mn)][Si26O72](OH)2Cl(OH,H2O)3 from Khibiny studied in this work.

DIFERENCIAÇÃO CATIÔNICA DE BENTONITAS POR INFRAVERMELHO: UM ESTUDO DOS EFEITOS DA HIDRATAÇÃO DOS CÁTIONS TROCÁVEIS

CATIONIC DIFFERENTIATION OF BENTONITES BY INFRARED: A STUDY OF THE HYDRATION EFFECTS OF EXCHANGEABLE CATIONS. In the bentonite industry, the most common procedure for quality control of the ore and the sodium activation process is the swelling method. However, this tool is restricted only to the differentiation of the sodium and non-sodium types, not considering the other cationic varieties. The objective of this study was to establish parameters for cationic differentiation of bentonites based on Near Infrared (NIR) and Medium (MIR) spectroscopy, which proved to be an effective technique in the cationic differentiation of bentonites using the characteristic bands “7072 cm-1” and “3620 and 3430 cm-1” under the condition of the dry-hydrated sample and not under the anhydrous condition. NIRS can be considered a measure of great scientific and technological contribution, as it allows the cationic differentiation of bentonites in a practical way and with low analytical cost.

Hollow single-crystalline octahedra of hydrated/dehydrated hydroxyl ferric phosphate and crystal-water-enhanced electrochemical properties of the hydrated sample for reversible lithiation–delithiation

Crystal water could modify lattice cell parameters and improve the lithium intercalation capability of Fe5(PO4)4(OH)3·2H2O hollow single-crystalline octahedra.

Influences of Water on the Hydration of Calcined Natural Calcite: Properties and Transesterification Activity Improvement

This paper presents the technique that can considerably improve basicity and transesterification activity of calcined natural calcite. Calcined calcite was refluxed in water followed by the calcinations at 600 oC. The characterization results indicate that this procedure substantially increases both the specific surface area and the amount of basic site. Hydration and subsequent calcination also generates a new calcium oxide with less crystalline. ME content was enhanced to 93.9 wt% in 1 hr from 75.5 wt% of calcined calcite. The results imply that the active sites produced by the calination of hydrated sample at 600 oC have higher basicity than those generated from calcinations of fresh calcite at 800 oC. The present study provides new insights for improving catalyst activity by tailoring the preparation conditions.

Electron spin resonance and electron spin echo spectroscopic studies of Cu2+ sites in synthetic cancrinite zeolites

Electron spin resonance (ESR) and electron spin echo modulation (ESEM) studies of Cu2+ sites introduced by ion exchange are reported in two types of synthetic cancrinite zeolites, one of them a more hydrated sample, Na6 Al6Si6O24•8H2O (denoted C1), and the other a less hydrated sample with entrained calcium carbonate, Na6Al6Si6O24•CaCO3•8H2O (denoted C2). ESR spectra reveal that C1 activated at 100 °C contains Cu2+ sites of tetrahedral symmetry with [Formula: see text] and [Formula: see text] while at a higher activation temperature of 400 °C Cu2+ sites with a different symmetry are produced corresponding to [Formula: see text] and [Formula: see text] C2 activated at 100 °C contains almost exclusively Cu2+ sites of trigonal symmetry with [Formula: see text] and [Formula: see text] Two- and three-pulse ESEM experiments at 4 K give 2D and 27Al modulation patterns that corroborate these ESR assignments. Possible locations of the Cu2+ sites in the C1 and C2 structures are proposed.