Analysis of Roman age wall paintings found in Pordenone, Trieste and Montegrotto

The aim of the present work is the study of many fragments of wall painting from archaeological excavations in three different Roman age sites dating back to the I Century before Common Era: Pordenone (località Torre); Trieste (Crosada) and Padova (Montegrotto). The techniques used were optical microscopy, scanning electron microscopy (SEM), equipped with a EDS microanalysis detector, X-rays powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Fourier transform Raman spectroscopy (FT-Raman) and electron paramagnetic resonance (EPR) spectroscopy. The identified pigments were: cinnabar, hematite, celadonite, glauconite, cuprorivaite (Egyptian blue), yellow and red ochre, calcite, limonite, coal black.In general, the mortar preparation did not correspond to the complex procedure suggested by Vitruvius (De Architectura), but generally showed a porous layer, with crushed grains under the pigment layer. In some cases, two superimposed pigment layers were found: yellow superimposed on both red and pink, black on pink, green on black.The slight differences we found in the use of the pigments in the three studied sites might show that the same technology, culture and taste spread all over the Roman Empire in North Eastern Italy (X^a Regio Venetia et Histria).     

Cholic acid derivatives containing both 2-naphthylcarbamate and 3,5-dinitrophenylcarbamate groups: a combined circular dichroism-molecular mechanics approach to the definition of their molecular conformation

CD spectra of the chiral auxiliaries for enantioselective HPLC N-allyl-N'-methyl-3,12-bis(2-naphthyl)carbamoyloxy-7-(3,5-dinitrophenyl)carbamoyloxycholan-24-amide (1), N-allyl-N'-methyl-3-(3,5-dinitrophenyl)carbamoyloxy-7,12-bis(2-naphthyl)carbamoyloxycholan-24-amide (2), N-allyl-N'-methyl-3,7-bis(2-naphthyl)carbamoyloxy-12-(3,5-dinitrophenyl)carbamoyloxycholan-24-amide (3), and N-allyl-N'-methyl-3,7,12-tris(2-naphthyl)carbamoyloxycholan-24-amide (4) are presented. To determine the preferred conformations of those chiral auxiliaries, a random search based on the aromatic side-chain conformational degrees of freedom was performed and the energy was minimized using two different molecular mechanics force fields. The low energy structures presenting common features were arranged in groups and selected exploiting appropriate filters. The calculation of theoretical CD spectra according to the De Voe model has allowed a further discrimination among the conformations, specifying which of them gave calculated CD spectra in acceptable agreement with the experimental ones. Finally, taking into account the additivity of the contributions of each 2-naphthylcarbamate chromophore to the CD spectrum of the cholic acid derivatives, and, hence, choosing, for derivatives 1-3, those conformations in which the 2-naphthylcarbamate groups take a similar disposition as in 4, the preferentially assumed conformation of each compound was obtained. A molecular dynamics simulation in the presence of acetonitrile allowed the fluctuations of one of the structures, used as a test case, depending on environmental effects, to be examined.     

Derivatives of imidazo[5,1-c][1,4]benzoxazin-l-ones and related analogs. Part I

The bicyclic 2,3,3a,4-tetrahydro-1H-imidazo[5,1-c][1,4]benzoxazin-1-one system and the related 1,4-benzo-thiazine and 4,1]benzoxazepine analogs were synthesized. They were easily obtained by melting a suitable diamine derivative with urea. Some of them displayed very good reversible MAO-I activity selective for type A. The preparation of the intermediate amines is also given.     

Hydrosilylation of 1-hexyne promoted by acetone solvated gold atoms derived catalysts

Supported gold nanoparticles, prepared by deposition of acetone solvated Au atoms on supports as carbon and γ-Al₂O₃, behave as valuable catalysts for the regioselective hydrosilylation of 1-hexyne with different silanes. The catalytic behaviour of gold-based systems is compared with the activity of supported platinum catalysts and a different affinity between the metals and the silanes is observed.     

Quasi-invariant manifolds,stability, and generalized Hopf bifurcation

Sunto Viene compiuta un'analisi completa del problema della biforcazione di Hopf relativa ad arbitrarie piccole perturbazioni del secondo membro di un'equazione differenziale in Rⁿ, p=f₀(p). Gli autovalori di f₀(O) soddisfano una condizione di non risonanza. I risultati sono forniti in termini delle proprietá di stabilità di un sistema dinamico piano convenientemente associato all'equazione imperturbata.

---

---

Research partially supported by U.S. Army Research Grant DAAG-29-80-C-0060 and by C.N.R. (Italian Council of Research) contr. 79.00696.01.

---

Work performed under the auspices of the National Group of Math, Phys. of C.N.R.     

Restricted rotation of the olefin and amine ligands in cis-dichloro(p-toluidine)(ethyl vinyl ether)platinum(II)

cis-Dichloro(p-toluidine)(olefin)platinum(II) complexes, in which the olefin is either ethyl vinyl ether or ethylene, have been investigated by ¹H NMR spectroscopy over a range of temperatures (+50 to ?60° C) in order to study the rotation of the olefin ligand.The results give no evidence of rotation of the amine or vinyl ether ligands even at the highest temperature investigated, +50°C; only one of the two possible rotational isomers is present, and this is attributed to the presence of intramolecular hydrogen bonding between the oxygen atom of the vinyl ether and the -NH- group of the amine.In contrast, the amine and vinyl ligands in the ethylene complex rotate freely at room temperature, coalescence being observed above ?25° C for the ethylene protons.     

Existence theorems for multiple integrals of the calculus of variations for discontinuous solutions

Summary The authors prove existence theorems for the minimum of multiple integrals of the calculus of variations with constraints on the derivatives in classes of BV possibly discontinuous solutions. To this effect the integrals are written in the form proposed by Serrin. Usual convexity conditions are requested, but no growth condition. Preliminary closure and semicontinuity theorems are proved which are analogous to those previously proved by Cesari in Sobolev classes. Compactness in L₁ of classes of BV functions with equibounded total variations is derived from Cafiero-Fleming theorems.     

Determination of bromazepam in human plasma by high-performance liquid chromatography with electrospray ionization tandem mass spectrometric detection: application to a bioequivalence study

A simple method using a one-step liquid-liquid extraction (LLE) followed by high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the determination of bromazepam in human plasma, using lorazepam as internal standard. The acquisition was performed in the multiple reaction monitoring mode, monitoring the transitions: m/z 316 > 182 for bromazepam and m/z 321 > 275 for lorazepam. The method was linear over the studied range (1-100 ng ml(-1)), with r(2) > 0.98, and the run time was 2.5 min. The intra- and inter-assay precisions were 2.7-14.6 and 4.1-17.3%, respectively and the intra- and inter-assay accuracies were 87-111 and 75.8-109.5%, respectively. The mean recovery was 73.7%, ranging from 64.5 to 79.7%. The limit of quantification was 1 ng ml(-1). At this concentration the mean intra- and inter-assay precisions were 14.6 and 7.1%, respectively, and the mean intra- and inter-assay accuracies were 102.5 and 104%, respectively. Bromazepam stability was evaluated and the results showed that the drug is stable in standard solution and in plasma samples under typical storage and processing conditions. The method was applied to a bioequivalence study in which 27 healthy adult volunteers (14 men) received single oral doses (6 mg) of reference and test bromazepam formulations, in an open, two-period, randomized, crossover protocol. The 90% confidence interval of the individual ratios (test formulation/reference formulation) for C(max) (peak plasma concentration), AUC(0-96) and AUC(0-inf) (area under the plasma concentration versus time curve from time zero to 96 h and to infinity, respectively) were within the range 80-125%, which supports the conclusion that the test formulation is bioequivalent to the reference formulation regarding the rate and extent of bromazepam absorption.