Особенности формирования пентагональных микрокристаллов никеля в сплошных электроосажденных покрытиях при избирательном ингибировании роста их отдельных граней

The paper presents experimental facts indicating the possibility of controlling the habitus of microcrystals, which are structural units of electrodeposited nickel coatings. The introduction of additives (inhibitors) into the electrolyte of a certain chemical composition affects on the evolution of individual crystallographic facets of growing microcrystals and initiates the growth of microcrystal facets with a certain crystallographic orientation. This leads to the production of a nickel coating mainly consisting of microcrystals containing disclination-type defects and exhibiting pentagonal symmetry.

Singpuria, a new genus of Eudicot flower from the latest Cretaceous Deccan Intertrappean Beds of India

A new bisexual flower, Singpuria kapgatei, gen. et sp. nov., is described from chert of latest Cretaceous age from the Deccan Intertrappean Beds at Singpur, Madhya Pradesh, in central India. The hypogynous, actinomorphic flower is ~1.6 mm wide, with distinct sepals and petals. The androecium consists of 18 tetrasporangiate, dithecal, basifixed anthers borne in radial pairs on nine bifurcate filaments. The gynoecium is superior and syncarpous, with pentagonal symmetry. Pollen from the stamens is tricolporate and microreticulate. The combined morphological features of this flower indicate that Singpuria is a eudicot with affinities in the Pentapetalae, but we have been unable to make a more precise assignment. Nevertheless, we consider it useful to place this rare fossil flower on record as an exemplary extinct member of the Deccan biota. Singpuria may represent a clade that was isolated on the Indian subcontinent and became extinct in response to environmental changes at the K/Pg boundary, or later in the Cenozoic as the land mass moved northward through new climate zones and collided with Eurasia.

Spatial Organization of Five-Fold Morphology as a Source of Geometrical Constraint in Biology

A basic pattern in the body plan architecture of many animals, plants and some molecular and cellular systems is five-part units. This pattern has been understood as a result of genetic blueprints in development and as a widely conserved evolutionary character. Despite some efforts, a definitive explanation of the abundance of pentagonal symmetry at so many levels of complexity is still missing. Based on both, a computational platform and a statistical spatial organization argument, we show that five-fold morphology is substantially different from other abundant symmetries like three-fold, four-fold and six-fold symmetries in terms of spatial interacting elements. We develop a measuring system to determine levels of spatial organization in 2D polygons (homogeneous or heterogeneous partition of defined areas) based on principles of regularity in a morphospace. We found that spatial organization of five-fold symmetry is statistically higher than all other symmetries studied here (3 to 10-fold symmetries) in terms of spatial homogeneity. The significance of our findings is based on the statistical constancy of geometrical constraints derived from spatial organization of shapes, beyond the material or complexity level of the many different systems where pentagonal symmetry occurs.

Spatial Organization of Five-Fold Morphology as a Source of Geometrical Constraint in Biology

A basic pattern in the body plan architecture of many animals, plants and some molecular and cellular systems is five-part units. This pattern has been understood as a result of genetic blueprints in development and as a widely conserved evolutionary character. Despite some efforts, a definitive explanation of the abundance of pentagonal symmetry at so many levels of complexity is still missing. Based on both, a computational platform and a statistical spatial organization argument, we show that five-fold morphology is substantially different from other abundant symmetries like three-fold, four-fold and six-fold symmetries in terms of spatial interacting elements. We develop a measuring system to determine levels of spatial organization in 2D polygons (homogeneous or heterogeneous partition of defined areas) based in principles of regularity in a morphospace. We found that spatial organization of five-fold symmetry is statistically higher than all other symmetries studied here (three to ten-fold symmetries) in terms of spatial homogeneity. The significance of our findings is based on the statistical constancy of geometrical constraints derived from spatial organization of shapes, beyond the material or complexity level of the many different systems where pentagonal symmetry occurs.

Deep questions about the nature of early-life signals: a commentary on Lister (1673) ‘A description of certain stones figured like plants’

In 1673, Martin Lister explored the preservation of ‘St Cuthbert's beads’ plus other fossil crinoid remains from approximately 350 Ma Carboniferous limestone in northern England. He used taphonomic evidence (transport, disarticulation, burial and cementation) to infer an origin as petrified plant remains, in contrast with his views expressed elsewhere that fossil mollusc shells could have formed abiogenically, by ‘plastic forces’ within rock. Lister also observed pentagonal symmetry, now seen as characteristic of living echinoderm skeletons. A postscript from John Ray supports Lister's ‘taphonomic’ observations and accepts the biogenicity of these fossil ‘vegetables’. Ray then concluded with a prophecy, predicting the discovery of comparable living fossils in remote ocean waters. These early discussions compare with current debates about the character of candidate microfossils from the early Earth and Mars. Interesting biomorphs are now tested against the abiogenic null hypotheses, making use of features such as those pioneered by Lister, including evidence for geological context, rules for growth and taphonomy. Advanced techniques now allow us to extend this list of criteria to include the nanoscale mapping of biology-like behaviour patterns plus metabolic pathways. Whereas the science of palaeobiology once began with tests for biogenicity, the same is now true for geobiology and astrobiology. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society .

Coordination Chemistry of Polynitriles, I. Syntheses and Crystal Structures of [Ag(PCC)(DMF)], [Ni(DMF)6](PCC)2 and [Co(DMF)6](PCC)2 (PCC = [C5(CN)5]-, DMF = N,N-Dimethylformamide) [1]

Recrystallization of silver pentacyanocyclopentadienide Ag[C5(CN)5] from N,N-dimethylformamide (DMF) gives the polymeric 1:1 complex [Ag{C5(CN)5}(DMF)] (1). The Ag+ cation is coordinated by three N atoms of three different [C5(CN)5]- anions and two O atoms of two DMF molecules. Each [C5(CN)5]- is coordinated via three neighboring CN groups to three different Ag+ ions, while each DMF molecule bridges two Ag+ ions via its O atom. Treatment of NiCl2 6H2O, CoCl2 6H2O or ZnCl2 with Ag[C5(CN)5] in DMF gives the DMF complexes [M(DMF)6][C5(CN)5]2 (M=Ni, 2; Co, 3; Zn, 4). The complexes 2 and 3 were characterized by X-ray diffraction and show octahedral [M(DMF)6]2+ cations with O-coordinated DMF molecules. The [C5(CN)5]- anions show ideal pentagonal symmetry