New Insights on the Vibrational Dynamics of 2-Methoxy-, 4-Methoxy- and 4-Ethoxy-Benzaldehyde from INS Spectra and Periodic DFT Calculations.

The dynamics of 2-methoxybenzaldehyde, 4-methoxybenzaldehyde, and 4-ethoxybenzaldehyde in the solid state are assessed through INS spectroscopy combined with periodic DFT calculations. In the absence of experimental data for 4-ethoxybenzaldehyde, a tentative crystal structure, based on its similarity with 4-methoxybenzaldehyde, is considered and evaluated. The excellent agreement between calculated and experimental spectra allows a confident assignment of the vibrational modes. Several spectral features in the INS spectra are unambiguously assigned and torsional potential barriers for the methyl groups are derived from experimental frequencies. The intramolecular nature of the potential energy barrier for methyl rotation about O-CH3 bonds compares with the one reported for torsion about saturated C-CH3 bonds. On the other hand, the intermolecular contribution to the potential energy barrier may represent 1/3 of the barrier height in these systems.

Chemosteometric regression models of heat exposed human bones to determine their pre-burnt metric dimensions.

OBJECTIVES: Heat exposure can lead to apparently random osteometric changes that hinder the application of metric methods used for biological profiling. The impracticality of using objective and burn-specific osteometric methods reduces the chances of establishing the biological profiles of unknown individuals based on their skeletal remains. We investigated the potential of chemometry analysis based on infrared spectroscopy to predict the amount of heat-induced osteometric changes and how this reflected into sex estimation. MATERIAL AND METHODS: Bones from 41 identified adult skeletons (24 females and 17 males with ages between 62 and 90 years old) were experimentally burnt to maximum temperatures ranging from 450°C to 1,100°C (attained after 65 to 240 min). Measurements were taken both before and after each experiment and powder samples were analyzed through FTIR-ATR. Correlations among heat-induced metric changes and chemometric indices (crystallinity index; B-type carbonates; carbonate [A + B] to carbonate B ratio; hydroxyl to phosphate ratio; 630 cm-1 , 1450 cm-1 , 3572 cm-1 , and 3642 cm-1 ) were tested. Significant variables were used to build regression models to predict heat-induced metric change which were then tested on an independent set of samples. Agreement in sex estimation between the pre- and post-burnt samples was also evaluated. RESULTS: All indices were significantly correlated to heat-induced metric changes (α = .01) and the highest correlations were obtained for the 630 cm-1 , 3572 cm-1 , and crystallinity index. We confirmed that regression models based on chemometrics obtained from infrared spectra through FTIR-ATR are better at estimating heat-induced metric changes affecting bone and at sexing remains than other osteometric methods such as those based on correction factors or on metric references specific to calcined bones. DISCUSSION: Regression models avoid the subjectivity associated with the application of other methods. While the latter can be applied only to calcined bones, which is difficult to assess sometimes, regression models can be applied to all bones regardless of their condition. Also, regression models have the advantage of allowing to infer about heat-induced metric change on a case-by-case basis.

Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy).

This study examines the geochemical and mineralogical variations in the ferruginous mineralisations that crop out within Grotta della Monaca, which is considered to be the most striking and best known example of a prehistoric iron mine-cave from the southern Apennines (Calabria, Italy). Previous archaeological research identified three local and distinct ancient exploitation phases of these ferruginous mineralisations: (1) an Upper Palaeolithic phase; (2) a Late Neolithic phase; and (3) a post-Medieval phase. These materials, which have various forms of complex mineralogical admixtures and range in colour from yellow-orange to red and darker brown shades, mainly consist of iron oxides/hydroxides (essentially goethite and lepidocrocite), which are often mixed with subordinate and variable amounts of other matrix components (carbonates, sulphates, arsenates, silicates and organic matter). Such ferruginous mineralisations generally correspond to geochemically heterogeneous massive dyke/vein/mammillary/stratiform facies that are exposed within the local caves along open fractures and inclined bedding planes and that partially cover cave wall niches/notches/pockets and ceiling cupolas/holes. Selected samples/sub-samples are analysed through a multi-technique approach with a handheld portable X-ray Fluorescence, X-ray Diffraction, micro-Raman and Fourier Transform Infrared spectroscope (both conventional and attenuated total reflection), which is combined with subsequent multivariate statistical analysis of the elemental concentration data. The geochemical and mineralogical results are used to individualise similar compositional clusters. As expected, the identified groups, each of which has very specific geochemical-mineralogical "fingerprints" and spatial distributions, enable us to identify the sampled ferruginous mineralisations. These specific mineral resources can be compared to similar raw materials that are found in other neighbouring archaeological sites, with obvious implications toward understanding local exploitation strategies through time and the exchanges and kinship networks of these materials.

Rather yield than break: assessing the influence of human bone collagen content on heat-induced warping through vibrational spectroscopy.

Warping has been used to determine the pre-burning condition of human skeletal remains. In the literature, this modification has been associated more often with the burning of fleshed and green bones, but it also arises during the burning of dry bones. The objective of this paper was to assess if bone collagen content has a significant effect on the occurrence of warping in a sample of experimentally burned human bones. The presence of collagen was analyzed in two different samples through a vibrational spectroscopy technology-FTIR. One of them was composed of 40 archeological bones from the seventeenth to twentieth centuries AD. The other one was composed of bones from 14 skeletons belonging to the 21st century identified skeletal collection. The results confirmed that the amide I band assigned to the collagen was much more intense in bones presenting heat-induced warping. Nonetheless, although significant (p = 0.040), the collagen content was not as useful as other variables to the regression model we proposed for explaining warping. Factors such as the maximum temperature (p < 0.001) and burning time (p = 0.001) contributed more significantly. Results demonstrated that the mere preservation of collagen is not enough to explain warping. Burning dynamics seem to have an important role as well although we failed to clearly document its specificities. Other factors such as the asymmetric distribution of collagen and other components within bone, the gravity force, the shape of the bone, and the position in which it is burned may also play an important role on heat-induced changes and require further analysis.

New sustained release of zidovudine matrix tablets - cytotoxicity toward Caco-2 cells.

OBJECTIVE: The aim of this study was to adjust the zidovudine (AZT) release from solid tablets to an ideal profile, by developing matrices comprising swellable polymers with nonswellable ones. METHODS: Directly compressed matrices comprised different ratios of hydroxypropylmethylcellulose K15M and K100M, ethylcellulose, and methacrylic acid (Eudragit(®) RS PO and Eudragit(®) RL PO) were prepared. Technological characterization and evaluation of the in vitro release behavior were carried out. Cell density and viability following drug exposure were evaluated by the SRB method, for the Caco-2 line, while cell morphology was assessed upon Trypan blue staining. RESULTS: A specific formulation containing 5% of each excipient - HPMC K15M, HPMC K100M, Eudragit(®) RS PO, and Eudragit(®) RL PO - was found to yield the best release profile. Application of the Korsmeyer-Peppas model to the dissolution profile evidenced that a non-Fickian (anomalous) transport is involved in the drug release. Regarding the influence of the tablets' composition on the drug's cytotoxic effect toward the Caco-2 cell line, a reduction of cell biomass (0-15%) was verified for the distinct AZT formulations tested, F19 having displayed the highest cytotoxicity, after 24 and 48 h of incubation. Additionally, a high reversibility of the AZT effect was observed. CONCLUSIONS: The results showed that the simultaneous application of both hydrophilic and hydrophobic polymers can modulate the drug release process, leading to an improved efficacy and patient compliance. All AZT formulations studied were found to be cytotoxic against Caco-2 cells, F19 being the most effective one.

Inelastic neutron scattering study of Pt(II) complexes displaying anticancer properties.

The well-known platinum(II) chemotherapeutic drugs cisplatin [cis-(NH(3))(2)PtCl(2)] and carboplatin [Pt(NH(3))(2)C(6)O(4)H(6)], as well as the analogous transplatin [trans-(NH(3))(2)PtCl(2)], were studied by inelastic neutron scattering (INS) spectroscopy, coupled to quantum mechanical methods, and some ancillary work with X-ray diffraction on powders. An assignment of the experimental spectra was carried out based on the calculated INS transition frequencies and intensities (at the DFT level), thereby achieving a good correspondence between the calculated and observed data. Unusually good-quality INS spectra were obtained from about 250 mg, which is the smallest sample of a hydrogenous compound for which a successful INS interpretation has been reported. The knowledge of the local configuration of this kind of complexes is essential for an accurate understanding of their activity, which will pave the way for the rational design of novel third-generation drugs comprising cisplatin- and carboplatin-like moieties.

Development and validation of a RP-HPLC method for the determination of zidovudine and its related substances in sustained-release tablets.

A reversed-phase high-performance liquid chromatography (RP-HPLC) method for the rapid and accurate quantification of zidovudine (AZT) in sustained release tablets during stability testing was developed. A Waters RP-18 XTerra™(®) column, using a water:methanol (80:20, v/v%) mobile phase at a flow rate of 1.0 ml min(-1), and UV detection at 266 nm, was employed. The method of validation parameters indicate a linear range of between 40.0 to 220.0 µg ml(-1) with an LOQ of 1.985 µg ml(-1) and an LOD of 0.655 µg ml(-1) for the analyte. The degradation products of AZT were isolated and characterized for the first time. There was a very little decline of antiviral by heat, and AZT did not completely degrade either by acid or alkaline hydrolysis. On the other hand, oxidation caused a higher degradation stress in the drug. Finally, the degradation products resulting from stress studies were not found to interfere with the detection of antiviral, which is an advantage of the presently proposed method.

Conformational and vibrational study of cis-diamminedichloropalladium(II).

A conformational and vibrational analysis of cis-diamminedichloropalladium(ii) (cDDPd) is reported. Several theoretical methods (from Hartree-Fock to Møller-Plesset and Density Functional Theory) combined with different all-electron basis-sets are evaluated, in view of determining the best suited strategy for accurately representing this molecule. This choice is based on the best compromise between accuracy and computational requirements. Different scaling models were tested for obtaining the best scaling schemes of the vibrational modes to be used in this type of inorganic systems. The structural parameters and vibrational results predicted by the calculations are compared with the corresponding experimental data, namely X-ray structure and vibrational spectra. Finally, a complete assignment of the cDDPd vibrational spectra is presented.

Use of effective core potential calculations for the conformational and vibrational study of platinum(II) anticancer drugs. cis-Diamminedichloroplatinum(II) as a case study.

In the light of the recognized anticancer properties of cisplatin-type inorganic systems, the exact knowledge of their conformational preferences is of the utmost importance for understanding their biological activity. The present study reports the use of theoretical (quantum mechanical) calculations for achieving this goal. An alternative calculation method to the use of the AE basis sets, both accurate and computationally feasible, was presently tested for the conformational and vibrational study of cis-diamminedichloroplatinum(II). Effective core potentials (ECPs) were used, within the HF methodology and, within the B3LYP and mPW1PW DFT protocols. The DFT methods (particularly mPW1PW) were found to be the best choice for describing cDDP (as compared to the HF methodology).