Acidic Monosaccharides become Incorporated into Calcite Single Crystals**

Carbohydrates, along with proteins and peptides, are known to represent a major class of biomacromolecules involved in calcium carbonate biomineralization. However, in spite of multiple physical and biochemical characterizations, the explicit role of saccharide macromolecules (long chains of carbohydrate molecules) in mineral deposition is not yet understood. In this study, we investigated the influence of two common acidic monosaccharides (MSs), the two simplest forms of acidic carbohydrates, namely glucuronic and galacturonic acids, on the formation of calcite crystals in vitro. We show here that the size, morphology, and microstructure of calcite crystals are altered when they are grown in the presence of these MSs. More importantly, these MSs were found to become incorporated into the calcite crystalline lattice and induce anisotropic lattice distortions, a phenomenon widely studied for other biomolecules related to CaCO₃ biomineralization, but never before reported in the case of single MSs. Changes in the calcite lattice induced by MSs incorporation were precisely determined by high-resolution synchrotron powder X-ray diffraction. We believe that the results of this research may deepen our understanding of the interaction of saccharide polymers with an inorganic host and shed light on the implications of carbohydrates for biomineralization processes.     

Using Machine Learning Algorithms for Water Segmentation in Gas Diffusion Layers of Polymer Electrolyte Fuel Cells

Transport in Porous Media - X-ray computed tomography (CT) is increasingly used to characterize the morphology of water distribution in gas diffusion layers (GDLs) for polymer electrolyte fuel cell...     

Statistical Properties of Conduction Electrons in an Isolated Metal Nanosphere

We explore differences between canonical and grand canonical ensembles of 500–2000 free electrons confined in a spherical well with a radius from 1.2 to 2 nm. The averaged occupation numbers of the electronic energy levels and their variances are calculated. For isolated Ag and Au particles, the sum of the variances of all occupation numbers differs from the corresponding bulk-metal value by a factor of 0.005 to 2.     

Reaction of metals with benzenediazonium tetrafluoroborate in aprotic solvents

The reaction of metals and glassy carbon with benzenediazonium tetrafluoroborate (BDFB) in aprotic solvents has been studied. During contact of Pt, Au, Ag, Pd, or V with glassy carbon in concentrated diazonium salt solution no change of color was observed. For Al, Ca, Cr, Cu, Fe, Ga, In, Mg, Li, Na, or Zn the process was accompanied by a rapid solution color change, rapid N₂ release and the loss of metal sample mass. The copper metal ionization-dissolution was studied by ultraviolet and visible absorption spectroscopy, along with gravimetric and volumetric measurements. A dissolution mechanism was proposed based on kinetic, infrared, and X-ray diffraction data. The 432 nm absorption band appearing after Cu-BDFB reaction indicates formation of the mixed complex [Cu(N₂C₆H₅·(N≡C-CH₃)₃]⁺ where the copper atom is covalently bonded to the azophenyl radical and coordinated to acetonitrile (ACN). This complex is thermodynamically unstable and decomposes slowly to a colorless crystalline and a black amorphous phase. The crystalline phase was identified as [Cu(NC-CH₃)₄]BF₄. The amorphous phase is a mixture of products formed by azophenyl and phenyl radical condensation.      

Facile access to a series of large polycondensed pyridazines and their utility for the supramolecular synthesis of coordination polymers

Domino cyclization of ketoenols and hydrazine leads to a series of polycondensed pyridazines, which reveal potential as rigid N-donor multidentate ligands for supramolecular synthesis of open coordination polymers.     

Complications in metathesis reactions involving Grignard reagents: Effect of solvent on products obtained from the interaction of PhMgBr with GaCl3 or InBr3

The important role of supporting solvent in transmetallation reactions involving Grignard reagents is highlighted in the formation and crystallisation of the Group 13 ‘ate’ species, [Mg₃Br₃Cl₂(Et₂O)₆][GaPh₂Br₂] (1), [Mg₃Br₅(Et₂O)₆][InPh₂Br₂] (2), [MgBr(THF)₅][GaPh₃Br] (3), [MgBr(THF)₅][InPh₃Br] (4), [Mg(THF)₆][GaPh₂Br₂]₂ (5) obtained by reaction of PhMgBr with gallium and indium halides. The compounds have been characterised by ¹H NMR, elemental analyses, and single-crystal X-ray diffraction.     

Preparation of Cu,Ni and Co oxides by a citric acid-aided route

Journal of Thermal Analysis and Calorimetry - Citrate precursors of copper, nickel and cobalt oxides, namely Cu(C6H7O7)2·5H2O, Ni(C6H7O7)2·2.5H2O and CoC6H6O7·6H2O, have been...     

On the Cauchy problem for the Kortewegde Vries equation with steplike finite-gap initial data II. Perturbations with finite moments

We solve the Cauchy problem for the Korteweg-de Vries equation with steplike quasi-periodic, finite-gap initial conditions under the assumption that the perturbations have a given number of finite derivatives with finite moments.     

Derivations of the Lie algebra of infinite strictly upper triangular matrices over a commutative ring

Let 𝒩(∞,R) be the Lie algebra of infinite strictly upper triangular matrices over a commutative ring R. We show that every derivation of 𝒩(∞,R) is a sum of diagonal and inner derivations.