Analysis of pigments from Roman wall paintings found in the "agro centuriato" of Julia Concordia (Italy)

The analysis of wall painting fragments recovered in the "agro centuriato" of Julia Concordia has been carried out by using Scanning Electron Microscopy equipped with an EDS microanalysis detector (SEM-EDS), Infrared Spectroscopy (FTIR) and X-Ray powder Diffraction (XRD). The pigments used have been identified and the data obtained suggest the presence of three rustic villas richly decorated also with Egyptian blue. The presence of white of aragonite suggest that these villas were decorated during the Imperial Age, in agreement with the recovery of high quality materials and a bronze statue.     

Syntheses of (-)-oleocanthal, a natural NSAID found in extra virgin olive oil, the (-)-deacetoxy-oleuropein aglycone, and related analogues

Phenolic compounds extracted from extra virgin olive oil have attracted considerable recent attention. One of the components, (-)-oleocanthal (1), an inhibitor of the COX-1 and COX-2 enzymes, possesses similar potency as the NSAID ibuprofen. In this, a full account, we disclose the first- and now second-generation syntheses of both enantiomers of the oleocanthals, as well as the first synthesis of the closely related (-)-deacetoxy-oleuropein aglycone and a series of related analogues for structure activity studies. To demonstrate the utility of the second-generation synthesis, multigram quantities of (-)-oleocanthal were prepared in 10 steps (14% overall yield) from commercially available D-lyxose.     

Experimental and theoretical characterization of MSi16(-), MGe16(-), MSn16(-), and MPb16(-) (M = Ti, Zr, and Hf): the role of cage aromaticity

Silicon (Si), germanium (Ge), tin (Sn), and lead (Pb) clusters mixed with a group-4 transition metal atom [M = titanium (Ti), zirconium (Zr), and hafnium (Hf)] were generated by a dual-laser vaporization method, and their properties were analyzed by means of time-of-flight mass spectroscopy and anion photoelectron spectroscopy together with theoretical calculations. In the mass spectra, mixed neutral clusters of MSi(16), MGe(16), and MSn(16) were produced specifically, but the yield of MPb(16) was low. The anion photoelectron spectra revealed that MSi(16), MGe(16), and MSn(16) neutrals have large highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of 1.5-1.9 eV compared to those of MPb(16) (0.8-0.9 eV), implying that MSi(16), MGe(16), and MSn(16) are evidently electronically stable clusters. Cage aromaticity appears to be an important determinant of the electronic stability of these clusters: Calculations of nucleus-independent chemical shifts (NICSs) show that Si(16)(4-), Ge(16)(4-), and Sn(16)(4-) have aromatic characters with negative NICS values, while Pb(16)(4-) has an antiaromatic character with a positive NICS value.     

New trends in nucleic acid based biosensors: University of Florence (Italy), 25-28 October 2003

The Workshop on "New Trends in Nucleic Acids Based Biosensors" was held at the University of Florence (Italy), from 25th to 28th October 2003. The workshop was funded by the European Science Foundation (ESF) within the programme "Functional Genomics" (Programme Area: DNA arrays and chips). This report describes the main arguments discussed during the workshop considering the state of art and the future trends in the field of nucleic acid-based biosensors, with particular attention on the aptamer field.     

Heavy metals in PM10 sampled in the urban area of Campi Salentina (Apulia, southern Italy)

The following paper shows results of PM10 level and Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn concentrations present in this fraction for filters collected in the urban area of Campi Salentina (Apulia, Southern Italy) in 2004 in order to inquire into air quality. PM10 and lead concentrations did not exceed the standard values sanctioned by Italian Legislature with average values equal to 36.54 +/- 14.57 microg x m(-3) and 9.19 +/- 5.24 ng x m(-3) respectively. Significant correlations have been found between the pairs Fe-Mn, Ni-V, Cr-Ni and Cd-Cr. This suggests that these metals have a similar pollution source probably due to metallurgical activity. Multivariate statistical analysis showed that it is possible to distinguish the PM10 samples collected in sampling periods with different meteorological conditions. Indeed, metals concentration increases for samples characterized by scarce rains or by winds prevailing from North or North-West and is reduced due to different meteorological conditions, although there are some exceptions.     

Radiochemical characterisation,heavy metal determination and morphologic evolution of coastal sediments in the Ravenna area (Italy)

The basic aim of this work was to achieve a preliminary but integrated characterisation of an area of the Ravenna littoral coastline. The use of suitable computerised procedures has allowed the reconstruction of the morphological evolution of this area by means of historical and recent cartography. Coastal sediments were characterised by sampling 3 cores at about 2 km offshore. The following aspects were studied: 1) Mineralogical characterisation of both the total and the fine fraction of sediments by X-ray Diffraction. 2) Characteristion of sedimentary horizons by radiodating. 3)Magnetic susceptibility profiling. 4) Determination of some heavy metals (Cu, Pb, Zn, Cd) by anodic stripping voltammetry.     

GC/MS analysis of pesticides in the Ferrara area (Italy) surface water: a chemometric study

The development of a network to monitor surface waters is a critical element in the assessment, restoration and protection of water quality. In this study, concentrations of 42 pesticides--determined by GC-MS on samples from 11 points along the Ferrara area rivers--have been analyzed by chemometric tools. The data were collected over a three-year period (2002-2004). Principal component analysis of the detected pesticides was carried out in order to define the best spatial locations for the sampling points. The results obtained have been interpreted in view of agricultural land use. Time series data regarding pesticide contents in surface waters has been analyzed using the Autocorrelation function. This chemometric tool allows for seasonal trends and makes it possible to optimize sampling frequency in order to detect the effective maximum pesticide content.     

Enantioselective synthesis of (2S,3R)-3-hydroxy-3-methylproline, a novel amino acid found in polyoxypeptins

The enantioselective synthesis of (2S,3R)-3-hydroxy-3-methylproline (3) was achieved by the Sharpless AD, regioselective opening of cyclic sulfate by NaN(3) and intramolecular ring-closing reaction. The reported route has the advantage of a high overall yield and good enantiomeric purity, as well as starting from readily available chemical substrates and inexpensive reagents.     

Comparative study of the bonding in the first series of transition metal 1:1 complexes M-L (M = Sc, ..., Cu; L = CO, N(2), C(2)H(2), CN(-), NH(3), H(2)O, and F(-))

The nature of the chemical bonding in the 1:1 complexes formed by the fourth period transition metals (Sc, ..., Cu) with 14 electrons (N(2), CN(-), C(2)H(2)) and 10 electrons (NH(3), H(2)O, F(-)) ligands has been investigated at the ROB3LYP/6-311+G(2d) level by the ELF topological approach. The bonding is ruled by the nature of the ligand. The 10 electrons and anionic ligands are very poor electron acceptors and therefore the interaction with the metal is mostly electrostatic and for all metal except Cr the multiplicity is given by the [Ar]c(n)() configuration of the metallic core (n = Z - 20). The electron acceptor ligands which have at least a lone pair form linear or bent complexes involving a dative bond with the metal and the rules proposed previously for monocarbonyls hold. In the case of ethyne, it is not possible to form a linear complex and the cyclic C(2)(v)() structure imposed by symmetry possesses two covalent M-C bonds, therefore the multiplicity is given by the local core configuration [Ar]c(n)() for all metals except Mn and Ni.     

Binding Patterns in Single-Ligand Complexes of NH(3), H(2)O, OH(-), and F(-) with First Series Transition Metals

Single-ligand complexes of first series transition metals with ammonia, water, hydroxide, and fluoride, many known in the gas phase, have been studied in calculations covering the 20 mono- and divalent cations and some very unusual binding patterns have been found. Binding energies and binding geometries were calculated at MP2 level, using a basis with a (6d/4d) contraction in the metal d space and 6-311+G sets for the ligands. The results were used to distinguish the effect of steadily increasing nuclear charge across the series from the varying effects of d shell occupation. Even with only one ligand, the M(2+) adducts displayed the familiar ligand field effects, d shell repulsion in the expected d(delta) < d(pi) < d(sigma) order being superimposed on a regular progression to stronger binding and shorter bonds; that progression was disturbed only at the d(5) and d(10) positions, when the d(sigma) orbital was occupied. Monovalent metal adducts behaved in strikingly different fashion, with irregular changes across early and late series metals in both bond length and bond strength. The irregularities are only partly attributable to the presence of both d(n)()(-)(1)s and d(n)() ground states in the series. The other part of the explanation is the binding of anionic ligands inside the radial maximum of the 4s orbital. At these distances the normal binding preference shown by H(2)O and NH(3) for d(n)() over sd(n)()(-)(1) cations is reversed. In contrast to steeply rising binding energies across the divalent metal ion adducts, the trend lines for the monovalent series are flat, the increments in nuclear charge being insufficent to offset the extra repulsion of electrons added to the d shell.     

Sediment metal contamination in a creek flowing from a pristine to an industrial area of Trieste Province (Italy)

The following metals: Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined by inductively coupled plasma - atomic emission spectroscopy (ICP-AES) in fluvial sediments of Rosandra Creek, using two different, strong and mild sediment decomposition methods. The purpose was to obtain information about the contamination by metals and distribution paths of pollutants in the area crossed by Rosandra Creek: this little river is the unique epigeous watercourse in the Italian Karst and very few data can be found in literature. In this area, we can find a natural park, but also agricultural activities and an industrial district that was recently defined as "polluted site of national interest". By comparing the results of the strong and mild extraction we have obtained the percentage of extraction and enrichment factors for each metal in the different sediments of the sites R2 and R3 exposed to pollution, while the site R1 was considered as a pristine one because situated in the natural park. The computed enrichment factors are generally not very high, but copper, lead and zinc have factors that require attention. The principal component analysis (PCA) shows that the typically anthropogenic metals (as Cr, Pb, Cu and Zn) constitute the first factor, while the lithogenic metals, as Fe and Ni, constitute the second one; moreover the score plots permit to classify and distinguish the 3 sites: site R3, possibly the more exposed to contamination, has high scores both for anthropogenic and lithogenic metals.     

A theoretical study of the structures, energetics, stabilities, reactivities, and out-of-plane distortive tendencies of skeletally substituted benzenes (CH)(5)XH and (CH)(4)(XH)(2) (X = B(-), N(+), Al(-), Si, P(+), Ga(-), Ge, and As(+)).

Ab initio molecular orbital theory at Hartree-Fock (HF), post-Hartree-Fock (MP2 and CCSD(T)), and the hybrid density functional theory (B3LYP) calculations were done on the mono-(CH)(5)XH and diskeletally substituted (CH)(4)(XH)(2) benzenes (X = B(-), N(+), Al(-), Si, P(+), Ga(-), Ge, and As(+)). The computed relative energies of the disubstituted isomers show interesting trends. While the ortho-isomer is the most stable for X = Ga(-), Ge, and As(+), meta was found to be the most stable for X = B(-), N(+), Al(-) and Si, and para was found to be the most stable for X = P(+). Various intricate factors that govern the relative stabilities, such as the sum of bond strengths in the twin Kekule forms, rule of topological charge stabilization (TCS), and electrostatic repulsion were critically examined. The sum of bond strengths in the twin Kekule forms was proved to be quite a successful measure in predicting the relative stability orders between ortho- and meta-/para-isomers. The rule of TCS breaks down especially in the presence of overwhelming factors such as the differences in the cumulative bond strengths of the two positional isomers; however, the stability ordering between the para- and meta-isomers is successfully predicted in most cases. The tendency for ring puckering increases a great deal especially when the substituents are from 3rd or 4th row. Extension of the popular inverse relationship between the thermodynamic stability and reactivity was found to be inapplicable for this class of compounds. The computed singlet-triplet energy differences and the chemical hardness (eta) values indicate that the skeletal substitution weakens the pi-strength of the benzenoid system and increases their reactivity.