Dodecanuclear [Cu(II)6Gd(III)6] nanoclusters as magnetic refrigerants

A novel dodecanuclear complex, [{(HL)(L)(DMF)Cu(II)Gd(III)(DMF)(H(2)O)}(6)]·6DMF (1; DMF = N,N-dimethylformamide), has been obtained using the ligand resulting from the condensation of 3-formylsalicylic acid with hydroxylamine (H(3)L). The exchange interaction between the phenoxo-bridged Cu(II) and Gd(III) ions is weak ferromagnetic (J = +1.01 cm(-1)). The combination of a high-spin ground state with small anisotropy leads to a significant magnetocaloric effect [-ΔS(m)(0-7 T) = 23.5 J K g(-1) K(-1) at ～2 K].     

Evaluation of UVA-Mediated Oxidative Damage to Proteins and Lipids in Extracorporeal Photoimmunotherapy

The combination of UVA and 8-methoxypsoralen (8-MOP) is known for the ability to produce reactive oxygen species (ROS) that react subsequently with DNA, lipids and proteins. In most studies concerned with UVA effects mediated by free radicals, UVA doses higher than those exhibiting beneficial clinical results in extracorporeal photoimmunotherapy (ECPI) were used. The present study was undertaken to determine markers of oxidative stress in plasma and cells from the buffy coat using conditions relevant for ECPI (cumulative UVA dose at the sample level < or = 2 J/cm2). Plasma exposed to UVA of 20 J/cm2 resulted in protein oxidation as well in crosslinking and fragmentation revealed by electrophoresis. Exposure of the buffy coat and plasma to considerably lower doses of UVA (up to 2 J/cm2) combined with various 8-MOP concentrations resulted neither in an increase of malondialdehyde as a marker of lipid peroxidation nor in a changed electrophoretic protein pattern. In these same experiments the total antioxidative capacity decreased to 65% of the initial value, suggesting that the antioxidative defense of plasma is able to cope with oxidative stress under ECPI conditions. These results were confirmed by data from 10 patients with scleroderma or cutaneous T-cell lymphoma during ECPI treatment. The present results suggest that, although ROS are formed during ECPI, gross oxidative damage does not occur. It is, however, possible, that specific effects mediated by oxygen radicals may co-trigger the photoimmunomodulatory effects of ECPI.     

Study of bradykinin metabolism in human and rat plasma by liquid chromatography with inductively coupled plasma mass spectrometry and orthogonal acceleration time-of-flight mass spectrometry.

Bradykinin is a small peptide that acts mainly as a hormone by activating specific receptors that confer protection against the development of hypertension. The efficacy of bradykinin is influenced by the activities of various kininases present in plasma and blood. In this study, both human and rat plasma were incubated with a labelled form of bradykinin (at 4 and 12.5 microM), that will be referred to as bromobradykinin. The metabolic fate of bromobradykinin was monitored by liquid chromatography coupled to an orthogonal acceleration time-of-flight mass spectrometer (oaTOF). Quantification measurements of the bromine-containing metabolites were performed on-line, via flow splitting, by inductively coupled plasma mass spectrometry (ICPMS). The data obtained highlighted that the mechanism(s) of bradykinin metabolism in human and rat plasma are different, with the metabolism of bradykinin in rat plasma being much more aggressive than that observed in human plasma. In addition to the known bradykinin metabolites, e.g. [1,5], [1,7] from ACE, [1,8] from carboxypeptidase and [2,9] from aminopeptidase activity, we have identified the presence of new bradykinin metabolites in both human and rat plasma. These have been identified as fragment [5], the amino acid phenylalanine, which was present in both the human and rat plasma and the fragments [2,8] and [4,8] in rat plasma. To our knowledge it is the first time that these fragments have been recorded in human and rat plasma. The occurrence of these new fragments provides evidence for the presence of potentially new enzymes and mechanisms of bradykinin metabolism. The method described here provides a powerful technique for monitoring the activity of the many kininases involved in bradykinin metabolism such as ACE (angiotensin I converting enzyme), carboxypeptidase N and aminopeptidase P. In addition, this procedure could be used as a screening assay for selecting and monitoring the actions of inhibitors of the enzymes implicated in bradykinin metabolism directly in plasma or serum.     

On the optimal approximation of bounded linear functionals in Hilbert spaces with inner product invariant in rotation or translation

Optimal numerical approximation of bounded linear functionals by weighted sums in Hilbert spaces of functions defined in a domain B ? $\text{C}$ or B ? $\text{R}$^m, invariant in rotation or translation (e.g. circle, circular annulus, ball, spherical shell, strip of the complex plane) and equipped with inner product invariant in rotation or translation are considered. The weights and error functional norms for optimal approximate rules based on nodes located angle-equidistant on concentric spheres or circles of B, for B invariant in rotation, and on nodes located equispaced on in B lying line, for B invariant in translation, are explicitly given in terms of the kernel function of the Hilbert space. A number of concrete Hilbert spaces satisfying the required conditions are listed.     

Usage de l'algèbre de lie SU(n) dans l'etude des systèmes quantiques a n etats. VII: Sur le “problème inverse”

Through a formalism developed in formr papers, some problems, set by the determination, from experimental data of the evolution equation of an n-states quantum system are considered.     

The Use of Principal Component Analysis for the Study of the Interaction of Anionic Surfactants with Hydroxypropyl-β- Cyclodextrin

The interaction of 11 sulfosuccinic acid ester anionic surfactants with hydroxypropyl--cyclodextrin (HPCD) were determined with reversed-phase thin-layer chromatography and the relative strength of interaction was calculated. The relationship between the strength of interaction and the physicochemical parameters of anionic surfactants was elucidated with principal component analysis (PCA). HPCD interacted with the anionic surfactants decreasing their hydrophobicity. The distribution of the points of the strength of interaction and physicochemical parameters on the two dimensional nonlinear map of PC loadings suggested that the strength of interaction between the anionic surfactants and HPCD is of mixed steric character, with hydrophobic and electronic forces being involved in the interaction.     

Spin exchange in low energy electron-ion collisions

The elastic scattering of an electron by a hydrogenic ion of charge (Z-1) is investigated. For scattering energiesE _kin in the eV region, where the Bohr-Sommerfeld parametery is large compared to one, the cross section for spin exchange of the electrons is found to be proportional toZ ^?2 andE ^?1 _kin. Spin exchange is dominated by radiative electron capture forZ>25.     

Measurements of the Protective Effect of Topically Applied Sunscreens using in vitro Three-dimensional Dermal and Skin Equivalents

Abstract— For preventing or minimizing acute and chronic skin damage caused by UV radiation, the use of sunscreens is probably the most important measure. To screen the protective efficacy of new sunscreen molecules or formulations against UV rays, we evaluated as in vitro testing methods the use of two three-dimensional models, a dermal equivalent (DE) and a skin equivalent (SE). The DE is composed of a porous collagen-glycosaminoglycans-chitosan matrix populated by normal human fibroblasts. The SE is comprised of a fully differentiated epidermis realized by seeding keratinocytes onto the DE. In this study, we demonstrated that the DE and SE models react to the deleterious effects of UVA and UVB. Then, we extended our research to the evaluation of their usefulness for photoprotection trials. Sunscreen agents (Euso-lex 8020 and 6300) and commercially available sunscreens (chemical and physical filter formulations) that protect the skin against either UVA or UVB were evaluated. The tested products were applied (n = 6) topically (10 μL) and incubated for 30 min prior to irradiation over a range of UVA (0-50 J/cm²) or UVB (0-5 J/cm²). The photoprotection provided by the tested sunscreen molecules and formulations was evaluated by measurement of residual cellular viability 24 h postirradiation using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) test and assessment of the inflammation response by interleukin-la release assay. When sunscreens were applied prior to UV exposure, a higher residual cellular viability versus control was obtained, demonstrating the photoprotective effects of the tested products. These in vitro models could be used for screening tests to evaluate the protective effects of sunscreen molecules and formulations, especially for UVA trials because there is a lack of consensus for an in vivo method.