Luminescence properties of Pt(II) complexes containing polypyridine ligands with extended aromatic moieties

The luminescence properties of eleven Pt(ii) complexes containing polypyridine ligands with extended aromatic moieties have been studied, both in acetonitrile fluid solution at 298 K and in butyronitrile rigid matrix at 77 K. For comparison purposes, also the phosphorescence properties of three free ligands at 77 K in butyronitrile have been investigated. The absorption spectra of all the compounds exhibit intense bands (epsilon in the range 10(4)-10(5) M(-1) cm(-1)) in the UV region, which are attributed to spin-allowed ligand-centered (LC) transitions, and moderately intense bands (epsilon in the range 10(3)-10(4) M(-1) cm(-1)) in the visible region, which receive contribution from both spin-allowed LC transitions and spin-allowed metal-to-ligand charge-transfer (MLCT) transitions. At low energy, less intense spin-forbidden MLCT bands are also present. At 77 K in rigid matrix, all the studied compounds exhibit structured and long-lived (lifetimes from 840 mus on the millisecond timescale) luminescence, which is attributed to triplet LC states in all cases. At room temperature in fluid solution the luminescence lifetime of all the compounds is largely shortened (nanosecond timescale), and most of the emission spectra are unstructured and red-shifted. For species exhibiting structured emission spectra even at room temperature, low luminescence quantum yields are always obtained (Phi < 10(4)), and their emission is assigned to triplet LC states, which mainly deactivate to the ground state by thermal-activated surface crossing to a closely-lying metal-centered (MC) triplet state. Compounds exhibiting unstructured emission show relatively high emission quantum yields (about 0.1) and their emission is assigned to a mixed LC/MLCT state.     

Asymmetric catalytic synthesis of enantiopure N-protected 1,2-amino alcohols

[reaction: see text] The asymmetric aminolytic kinetic resolution (AKR) of racemic terminal epoxides using carbamates as the nucleophile catalyzed by (salen)Co(III) complex provides a practical and straightforward method for the synthesis of both aliphatic and aromatic N-Boc- or N-Cbz-protected 1,2-amino alcohols in almost enantiomerically pure form (ee >/= 99%). The AKR uses an easily accessible catalyst and inexpensive starting materials, and the reactions are conveniently carried out at room temperature under an air atmosphere.     

The weathering of natural and artificial stones in the baroque church of S. Pietro in Valle (Fano-Italy)

The church of San Pietro in Valle in Fano is with good reason considered one of the outstanding examples of baroque art in Central Italy. Currently the church is in a serious degradation status. For this reason, and in order to devise a correct conservative restoration project, a scientific study has been carried out, aimed at characterizing mortars used for the application of marble decorations and the different degradation products occurring in the church (i.e. pulverizations, encrustations, salt efflorescences, and condensation water). In the following, results obtained analyzing the different sample typologies by optical microscopy, X-ray diffraction, electron scanning microscopy with energy-dispersion micro-analytical system, ion chromatography, and head-space solid phase microextraction-gas chromatography-mass spectrometry will be reported.     

Molecular systematics and ultrastructural characterization of a forgotten species: Chattonidium setense (Ciliophora,Heterotrichea)

In the present paper we redescribe the ciliate Chattonidium setense Villeneuve 1937 combining morphological observations (live, stained, scanning, and transmission electron microscope) with behavioral notes and molecular data. Ultrastructural analysis revealed remarkable similarities between Chattonidium and representative members of the class Heterotrichea in cortical structure and cytoplasmic organization. The most similar genus for these aspects appears to be Condylostoma. To verify this relatedness, 18S rRNA genes from Chattonidium and from one Condylostoma species were sequenced. Phylogenetic analysis indicates Chattonidium belongs to the class Heterotrichea defined according to the modern taxonomy, and confirms its relatedness with Condylostoma already hypothesized by Villeneuve-Brachon (1940). The presence of the aboral cavity complex, a unique feature never described in other ciliates, and its peculiar organization revealed by ultrastructural analysis fully justify, in our opinion, the maintenance of Chattonidium in the separate family Chattonidiidae, established by Villeneuve-Brachon in 1940.     

Monitoring the Interaction of α-Synuclein with Calcium Ions through Exclusively Heteronuclear Nuclear Magnetic Resonance Experiments

Many properties of intrinsically disordered proteins (IDPs), or protein regions (IDRs), are modulated by the nature of amino acid side chains as well as by local solvent exposure. We propose a set of exclusively heteronuclear NMR experiments to investigate these features in different experimental conditions that are relevant for physiological function. The proposed approach is generally applicable to many IDPs/IDRs whose assignment is available in the Biological Magnetic Resonance Bank (BMRB) to investigate how their properties are modulated by different, physiologically relevant conditions. The experiments, tested on α-synuclein, are then used to investigate how α-synuclein senses Ca²⁺ concentration jumps associated with the transmission of nerve signals. Novel modules in the primary sequence of α-synuclein optimized for calcium sensing in highly flexible, disordered protein segments are identified.     

Lubich convolution quadratures and their application to problems described by space-time BIEs

In the last years several authors have used Lubich convolution quadrature formulas to discretize space-time boundary integral equations representing time dependent problems. These rules have the fundamental property of not using explicitly the expression of the kernel of the integral equation they are applied to, which is instead replaced by that of its Laplace transform, usually given by a simple analytic function. In this paper, a review of these rules, which includes their main properties, several new remarks and some conjectures, will be presented when they are applied to the heat and wave space-time boundary integral equation formulations. The construction and behavior of the corresponding coefficients are analyzed and tested numerically. When the quadrature is defined by a BDF method, a new approach for the representation of its coefficients is presented.     

Anti-angiogenic activity evaluation of secondary metabolites from Calycolpus moritzianus leaves

Angiogenesis is a crucial step in many pathological conditions like cancer, inflammation and metastasis formation; on these basis the search for antiangiogenic agents has widened. In order to identify new compounds able to interfere in the Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1, also known as Flt-1) recognition by VEGFs family members, we screened Calycolpus moritzianus (O. Berg) Burret leaves extracts by a competitive ELISA-based assay. MeOH and CHCl3 extracts and several their fractions demonstrated to be able to prevent VEGF or PlGF interaction with Flt-1, with an inhibition about 50% at concentration of 100 microg/mL. Phytochemical and pharmacological investigation of the active fractions led to the isolation of flavonoids, and terpenes.