Enzymatic Approach to and Odor Description of the Twelve Enantiomerically Pure Isomers of Pelargene®

Pelargene^® is a commercial fragrance sold as a mixture of three regioisomeric pyran derivatives ( 1 – 3 ). The enantiomers of each of the two possible diastereoisomers of 1 – 3 were prepared by means of a biocatalyzed approach, and the odor properties of the twelve isolated stereoisomers were evaluated.     

The use of sequential extraction procedures for the characterization and management of contaminated soils

Metal mobility and availability in solid samples, such as soils, sediments and sludges, is frequently studied with sequential extraction procedures, which allow to partition the total metal content into classes of different reactivity. From the experimental point of view, each extraction step requires many practical operations, which can represent sources of error if they are not properly executed. The first part of the paper gives indication on how to perform sequential extractions, from sample pretreatment to extract analysis, in order to reduce experimental errors. The second part describes the main applications of sequential extraction schemes for the characterization and management of contaminated soils: the assessment of the risks associated to metal pollution, the evaluation of the feasibility and efficiency of remediation techniques, the study of soil properties and of metal behaviour and plant availability.     

Formulation and Preliminary in vivo Testing of Rufloxacin-Cyclodextrin Ophthalmic Solutions

Aim of the present work was to investigate the effect of somecyclodextrins (CDs) on the solubility and ocular bioavailability of rufloxacin base (RUF), with theultimate goal of developing an ophthalmic formulation. Phase solubility studies of RUF inpH 7.4 buffer were carried out in the presence of -cyclodextrin (-CD),hydroxypropyl--cyclodextrin (HP--CD) and -cyclodextrin(-CD). The effect of hydroxypropyl methylcellulose (HPMC) on RUF solubility was evaluated after heating the solutionscontaining HP--CD at 120 °C.A significant enhancement of RUF solubility was achieved by associatingthe drug with CDs, particularly HP--CD. This CD formed with RUF a less stablecomplex than that formed by -CD, but did not suffer the solubility limitations ofthe parent CD, and showed a higher solubilizing capacity than -CD. Addition of 0.25%(w/v) HPMC to solutions containing HP--CD increased the solubilizing effect of this CD,thus allowing reduction of the amount necessary for solubilization of 0.3% (w/v) RUF.Preliminary pharmacokinetic data in rabbits indicated that theocular bioavailability of 0.3% (w/v) RUF solubilized by HP--CD was higher when compared witha 0.3% (w/v) RUF suspension used as reference.     

One-dimensional non-coercive problems of the calculus of variations

We establish a necessary and sufficient condition for the existence of the minimum of the functional dt in the class in terms of a limitation on the slope d. We derive some applications regarding quasi-coercive and non-coercive integrands.     

EXAFS and XANES joint analyses for semiconducting vanadium phosphate glasses

Vanadium EXAFS spectra of 50V₂O₅-50P₂O₅ glasses with different C = V⁺⁴/V_tot have been measured. The V-O distances increase by ΔR₁ = (0.03 ± 0.02) Å to ΔR₂ = (0.07 ± 0.03) Å going from a glass with C = 0.64 to C = 0.84 and from C = 0.51 to C = 0.84, respectively. The EXAFS data show a basically similar structure of the vanadium sites for both the V⁴⁺ and V⁵⁺ ionic states. The density of the glasses increases with C from the value d₁ = 2.81 g/cm³ for C = 0.51 to d₂ = 2.92 g/cm³ for C = 0.84 indicating a more random packing of glass units.     

Simulating the active sites of copper-trafficking proteins. Density functional structural and spectroscopy studies on copper(I) complexes with thiols,carboxylato, amide and phenol ligands

A series of mononuclear binary and ternary Cu(I) complexes with formato, formamide, methylphenol, and methanethiolato ligands were optimized at DFT-B3LYP/6-31G** (BS1) and DFT-B3LYP/6-311++G** (BS2) levels of theory. The solvent effect was taken into account via PCM method (BS1W and BS2W, respectively). The coordination arrangement for [Cu^I(SCH₃/S(H)CH₃)(OOCH)]^?/0 and [Cu^I(SCH₃/S(H)CH₃)(O(H)(C₆H₄)CH₃)]^0/+ was pseudo-linear and for [Cu^I(SCH₃/S(H)CH₃)(OOCH)(OC(H)NH₂)]^?/0 was pseudo-trigonal. The [Cu^I(S-S(H)CH₃/Cu^I(S-SCH₃)]^+/0 link even to amide carbonyl and to general O(H)R residues (R=C₆H₅CH₃). [Cu^I(SCH₃)₂(O(H)(C₆H₄)CH₃)]^? went towards dissociation of the O(H)(C₆H₄)CH₃ ligand, whereas [Cu^I(S(H)CH₃)₂(O(H)(C₆H₄)CH₃)]⁺ converged nicely, maintaining the hydroxy function linked to the metal. The trends of total electronic energies seemed to be significant, suggesting that linear Cu^IS₂ coordination is more suitable than Cu^IS, Cu^IS₃ and Cu^IS₄ arrangements. The formation energies of [Cu^I(S(H)CH₃/SCH₃)(OOCH)]^0/?1 were higher than those of [Cu^I(S(H)CH₃/SCH₃)₂]^+/? on starting from [Cu^I(S(H)CH₃/Cu^I(SCH₃)]^+/0 by ca. 11–9 kcal mol^?1 (BS2W). The structural arrangements, bond distances, and angles as well as computed spectroscopic parameters resulted in good agreement with experimental data for corresponding synthetic complexes and with metal site regions of several copper(I)-proteins. These data help in interpreting structural data of complex biological systems and in constructing reliable force fields for molecular mechanics computations.     

Nearest surroundings of aluminum atoms and features of the electron structure of Al90FexCe10−x alloys (x=3, 5, 7)

The spectra of x-ray absorption near-edge structure (XANES) were measured at the K-edge of aluminum in Al₉₀Fe_xCe_{10 ?x} alloys (x=3, 5, 7). A theoretical XANES analysis at the Al K-edge was performed for Al₉₀Fe₅Ce₅ by using the multiple scattering algorithm. A comparison of the experimental and theoretical results allowed establishment of the most probable model of local surroundings of aluminum atoms in the alloy system studied. The density of free Al and Fe electron states in the conduction band was determined. It was found that the interaction between Al p states and Fe d states leads to pushing of the former states by the latter ones.     

Synchrotron radiation FTIR imaging in minutes: a first step towards real-time cell imaging

FTIR microscopy with a focal plane array (FPA) of detectors enables routine chemical imaging on individual cells in only a few minutes. The brilliance of synchrotron radiation (SR) IR sources may enhance the signal obtained from such small biosamples containing small amounts of organic matter. We investigated individual cells obtained from a cell culture specifically developed for transmission FTIR imaging using either a Globar or an SR source coupled to the same instrumentation. SR-IR source focussing was optimized to control the energy distribution on the FPA of detectors. Here we show that accessing the IR absorption distribution from all the organic contents of cells at 1 × 1 μm pixel resolution was possible only with high circulating current (≥1.2 A) illuminating a limited number of the FPA’s detectors to increase the signal-to-noise ratio of IR images. Finally, a high-current SR ring is mandatory for collecting FTIR images of biosamples with a high contrast in minutes.     

In vivo skin leptin modulation after 14 MeV neutron irradiation: a molecular and FT-IR spectroscopic study

This paper discusses gene expression changes in the skin of mice treated by monoenergetic 14 MeV neutron irradiation and the possibility of monitoring the resultant lipid depletion (cross-validated by functional genomic analysis) as a marker of radiation exposure by high-resolution FT-IR (Fourier transform infrared) imaging spectroscopy. The irradiation was performed at the ENEA Frascati Neutron Generator (FNG), which is specifically dedicated to biological samples. FNG is a linear electrostatic accelerator that produces up to 1.0 × 10(11) 14-MeV neutrons per second via the D-T nuclear reaction. The functional genomic approach was applied to four animals for each experimental condition (unirradiated, 0.2 Gy irradiation, or 1 Gy irradiation) 6 hours or 24 hours after exposure. Coregulation of a subclass of keratin and keratin-associated protein genes that are physically clustered in the mouse genome and functionally related to skin and hair follicle proliferation and differentiation was observed. Most of these genes are transiently upregulated at 6 h after the delivery of the lower dose delivered, and drastically downregulated at 24 h after the delivery of the dose of 1 Gy. In contrast, the gene coding for the leptin protein was consistently upregulated upon irradiation with both doses. Leptin is a key protein that regulates lipid accumulation in tissues, and its absence provokes obesity. The tissue analysis was performed by monitoring the accumulation and the distribution of skin lipids using FT-IR imaging spectroscopy. The overall picture indicates the differential modulation of key genes during epidermis homeostasis that leads to the activation of a self-renewal process at low doses of irradiation.