Interaction of MOPS buffer with glass-ceramic scaffold: Effect of (PO ) ions in SBF on kinetics and morphology of formatted hydroxyapatite.

The international standard ISO 23317:2014 for the in vitro testing of inorganic biomaterials in simulated body fluid (SBF) uses TRIS buffer to maintain neutral pH. In our previous papers, we investigated the interaction of a glass-ceramic scaffold with TRIS and HEPES buffers. Both of them speeded up glass-ceramic dissolution and hydroxyapatite (HAp) precipitation, thereby demonstrating their unsuitability for the in vitro testing of highly reactive biomaterials.

Unusual Cage Rearrangements in 10-Vertex nido-5,6-Dicarbaborane Derivatives: An Interplay between Theory and Experiment.

The reaction between selected X-nido-5,6-CBH compounds (where X = Cl, Br, I) and "Proton Sponge" [PS; 1,8-bis(dimethylamino)naphthalene], followed by acidification, results in extensive rearrangement of all cage vertices. Specifically, deprotonation of 7-X-5,6-CBH compounds with one equivalent of PS in hexane or CHCl at ambient temperature led to a 7 → 10 halogen rearrangement, forming a series of PSH[10-X-5,6-CBH] salts. Reprotonation using concentrated HSO in CHCl generates a series of neutral carbaboranes 10-X-5,6-CBH, with the overall 7 → 10 conversion being 75%, 95%, and 100% for X = Cl, Br, and I, respectively.

Interaction of HEPES buffer with glass-ceramic scaffold: Can HEPES replace TRIS in SBF?

An international standard (ISO: 23317:2014) exists for the in vitro testing of inorganic biomaterials in simulated body fluid (SBF). This standard uses TRIS buffer to maintain neutral pH in SBF, but in our previous paper, we showed that the interaction of a tested glass-ceramic material with TRIS can produce false-positive results. In this study, we evaluated whether the HEPES buffer, which also belongs to the group of Good´s buffers, would be more suitable for SBF.

Influence of Antipodally Coupled Iodine and Carbon Atoms on the Cage Structure of 9,12-I2-closo-1,2-C2B10H10: An Electron Diffraction and Computational Study.

Because of the comparable electron scattering abilities of carbon and boron, the electron diffraction structure of the C2v-symmetric molecule closo-1,2-C2B10H12 (1), one of the building blocks of boron cluster chemistry, is not as accurate as it could be. On that basis, we have prepared the known diiodo derivative of 1, 9,12-I2-closo-1,2-C2B10H10 (2), which has the same point-group symmetry as 1 but in which the presence of iodine atoms, with their much stronger ability to scatter electrons, ensures much better structural characterization of the C2B10 icosahedral core. Furthermore, the influence on the C2B10 geometry in 2 of the antipodally positioned iodine substituents with respect to both carbon atoms has been examined using the concerted application of gas electron diffraction and quantum chemical calculations at the MP2 and density functional theory (DFT) levels.

Doping of Zinc Oxide with Selected First Row Transition Metals for Photocatalytic Applications.

ZnO doped with Cr, Mn, Fe, Co, Ni and Cu was prepared by homogeneous hydrolysis of sulfates with urea. The samples were annealed at various temperatures and characterized by X-ray powder diffraction, UV/VIS reflectance spectroscopy, BET (Brunauer-Emmet-Teller) surface area and porosity measurements. The photocatalytic activity of the samples was evaluated by measuring the degradation of an organic dye Reactive Black 5.

A comparative study of the redox and excited state properties of (nBu4N)2[Mo6X14] and (nBu4N)2[Mo6X8(CF3COO)6] (X = Cl, Br, or I).

The excited-state dynamics, luminescence, and redox properties of a series of hexanuclear molybdenum cluster complexes, (nBu4N)2[Mo6X14] and (nBu4N)2[Mo6X8(CF3COO)6] (X = Cl, Br, or I), were investigated. Substitution of the apical halogen ligands for the trifluoroacetate ligands increased the oxidation potentials and induced a blue shift in the absorption and luminescence bands as well as a considerable increase in the luminescence quantum yields for heavy inner ligands. Time-resolved transient absorption measurements showed that the intersystem crossing from the excited singlet states is ultrafast with time constants ranging between <120 fs and 1.

Cationic closo-carboranes 2. Do computed 11B and 13C NMR chemical shifts support their experimental availability?

(11)B and (13)C NMR spectra of so-far experimentally unknown carbon-rich cationic closo-carboranes C(3)B(n-3)H(n)(+) (n = 5, 6, 7, 10, 12) have been calculated at the GIAO-MP2 level and subsequently analyzed to reveal the nature of bonding in these potentially weakly coordinating cations. All previous rules derived for understanding (11)B NMR spectra of borane derivatives can be applied to realistically account for the corresponding shieldings. The correlated wavefunction for n = 5 and, to a lesser extent, for n = 10 seems to be decisive when trying to compute realistic shielding tensors, which is in agreement with the corresponding known dicarbaboranes.

Why is the antipodal effect in closo-1-SB9H9 so large? A possible explanation based on the geometry from the concerted use of gas electron diffraction and computational methods.

The molecular structure of 1-thia-closo-decaborane(9), 1-SB(9)H(9), has been determined by the concerted use of gas electron diffraction and quantum-chemical calculations. Assuming C(4v) symmetry, the cage structure was distorted from a symmetrically bicapped square antiprism (D(4d) symmetry) mainly through substantial expansion of the tetragonal belt of boron atoms adjacent to sulfur. The S-B and (B-B)(mean) distances are well determined with r(h1) = 193.

Does 2-methylacetophenone comply with steric inhibition of resonance? A direct experimental proof of its nonplanar conformation from a joint ab initio/electron diffraction analysis.

The structure and conformations of 2-methylacetophenone (1) have been investigated by ab initio calculations carried out at the MP2(full)/6-311++G** level and by gas electron diffraction (GED). According to both methods, 1 exists predominantly as a form with the C=O bond synclinal with respect to the C(ar)-C(O) bond (1B), with a torsional angle [C(6)-C(1)-C=O] of 32.7(24) degrees as determined by GED and 26.

Micro-analytical evidence of origin and degradation of copper pigments found in Bohemian Gothic murals.

Correct identification of pigments and all accompanying phases found in colour layers of historical paintings are relevant for searching their origin and pigment preparation pathways and for specification of their further degradation processes. We successfully applied the analytical route combining non-destructive in situ X-ray fluorescence analyses with subsequent laboratory investigation of micro-samples by optical microscopy, scanning electron microscopy/energy-dispersive spectroscopy and X-ray powder micro-diffraction (micro-XRD) to obtain efficiently all the data relevant for mineralogical interpretations of the copper pigments origin. Cu salts (carbonates, chlorides, sulphates, etc.

Stereochemistry of free boranes and heteroboranes from electron scattering and model chemistries.

The development of modern computational methods, linked to improved methods for analysis of experimental gas-phase structural data, has allowed the stereochemistry of many boranes and heteroboranes to be determined with great accuracy over the past two decades. Many of these compounds have been prepared in the Institute of Inorganic Chemistry of the Academy of Sciences of the Czech Republic, and gas-phase electron diffraction (GED) data have been obtained mainly at the University of Edinburgh. Structural tools based on the concerted use of GED and computations of the geometries and "B chemical shifts (MOCED, SARACEN) have also been employed.