Groups whose cyclic subgroups have bounded permutability properties

It follows from classical results of Neumann and Macdonald that a group G has finite commuator subgroup if and only if either the normalizers of cyclic subgroups of G have boundedly finite indices or cyclic subgroups of G have bounded indices in their normal closures. In this paper, groups with a similar condition are considered, when normality is replaced by permutability.      

Aspects of cell production in mantle tissue of Ciona intestinalis L. (Tunicata, Ascidiacea)

Renewal of cell population is needed in the tunic of ascidians, as the tunic cells are involved in many biological functions. Tunic cells are thought to arrive by migrating across the mantle epithelium into the tunic from the blood lacunae or the mesenchymal space. Electron microscope observations show that the mantle epithelium of Ciona intestinalis shares some proliferative characteristics, releasing cells into the tunic and thus providing an increase renewal of tunical cells in restricted zones of adult animals.     

New high-nuclearity Ni-Pt carbonyl clusters: synthesis and X-ray structure of the ordered [HNi24Pt17(CO)46]5- and the substitutionally Ni/Pt disordered [Ni32Pt24(CO)56]6- cluster anions

Condensation between preformed Ni-Pt and Pt carbonyl clusters leads to the new [H(6-n)Ni(24)Pt(17)(CO)(46)](n-)(n= 5, 6) and the substitutionally Ni/Pt disordered [Ni(24)(Ni(12-x)Pt(x))Pt(20)(CO)(56)](6-) (x = 4) carbonyl clusters, the latter of which represents the highest nuclearity homoleptic carbonyl cluster anion so far reported.     

Influence of the coordination geometry on the physicochemical properties of a copper(II) complex with a tailor-made calixarene-based ligand bearing dipyridyl pendants. An ESR, UV-Vis and CV study

Dipyridyl pendants, suitably attached onto a calix[4]arene fixed in its 1,3-alternate conformation, form stable complexes with copper(ii) in acetonitrile. Both the mononuclear and the homobinuclear species ([Cu(1)](2+) and [Cu(2)(1)](4+)), previously detected through a UV-Vis investigation, have been studied by ESR, UV-Vis and cyclic voltammetry. ESR and UV-Vis data clearly indicate that in the [Cu(1)](2+) species the nitrogen atoms of dipyridyl pendants are tetrahedrally arranged around copper(II). Computer models, optimised through molecular mechanics methods, further support these spectroscopic findings. The tetrahedral arrangement, achieved thanks to the anchoring of the dipyridyl moieties onto the calixarene platform, accounts for the easy reversible reduction of this species. The aspects associated with the reduction-oxidation of the homobinuclear species are also discussed.     

A data-driven model of the COVID-19 spread among interconnected populations: epidemiological and mobility aspects following the lockdown in Italy

Nonlinear Dynamics - An epidemic multi-group model formed by interconnected SEIR-like structures is formulated and used for data fitting to gain insight into the COVID-19 dynamics and into the role...     

Trace metal concentration in wild avian species from Campania,Italy

This study was conducted to determine heavy metals concentrations in tissues of 94 birds belonging to different species from coastal areas of Naples and Salerno (Southern Italy) in order to provide baseline data concerning trace element levels in wild birds living in or close to an area characterized by high anthropogenic impact. Additional aim of this study was to verify if diet influenced metal accumulation, so birds were classified as birds of prey, fish eating birds and insectivorous birds.