Structural and Dynamical Insights from Vibrational Multipolar Analyses of Isotropic Media: Application to Molecular Liquid CCl4 and Silica Glass SiO2

We propose and describe combined multipolar vibrational decompositions of IR, polarized Raman and hyper-Raman spectra as a powerful method to study and interpret vibrational spectra in isotropic materials. We have applied this new method to the molecular liquid CCl4 and to silica glass, which are both made of elementary tetrahedral units weakly interacting and strongly 3D-linked, respectively. As expected, huge deviations of vibrational multipolar activities from isolated tetrahedron are observed in silica glass. From the vibrational multipolar analyses, we propose a structural model, beyond the local tetrahedral unit, because it encompasses first neighborhoods, which fits the activities of the multipolar vibrational spectra. It is derived from the unit cell of the α-cristoballite structure, with an octupolar S4 symmetry, which consists of a central SiO4 tetrahedron embedded in a super Si4/4 tetrahedron with bent Si?O?Si bonds.Research and Education in Glass and Laser Interaction Science (REGLIS

Chiroptical and Potential In Vitro Anti-Inflammatory Properties of Viniferin Stereoisomers from Grapevine (Vitis vinifera L)

International audienceDetermination of stereochemistry and enantiomeric excess in chiral natural molecules is a research of great interest because enantiomers can exhibit different biological activities. Viniferin stilbene dimers are natural molecules present in grape berries and wine but also, in larger amount, in stalks of grapevine. Four stereoisomers of viniferin stilbene dimers (7aS,8aS)-E-ε-viniferin (1a), (7aR,8aR)-E-ε-viniferin (1b), (7aS,8aR)-Eε-viniferin (2a), and (7aR,8aS)-E-ω-viniferin (2b) were isolated from grapevine stalks of Cabernet Sauvignon, Merlot and Sauvignon Blanc, using a combination of centrifugal partition chromatography (CPC), preparative and chiral HPLC. The structure elucidation of these molecules was achieved by NMR whereas the absolute configurations of the four stereoisomers were investigated by vibrational circular dichroism spectroscopy in combination with density functional theory (DFT) calculations. This study unambiguously established the (+)-(7aS,8aS) and (+)-(7aR,8aS) configurations for E-ε-viniferin and E-ω-viniferin, respectively. Finally, we show that Cabernet Sauvignon provided the quasi enantiopure (+)-(7aS,8aS)-E-εviniferin compound which presents the best anti-inflammatory and anti-oxidant activities

Nanoscale Archimedean Tilings Formed by 3‐Miktoarm Star Terpolymer Thin Films

3-Miktoarm star terpolymer architecture (3 mu-ABC), consisting of three dissimilar polymer chains, A, B, and C connected at a junction point, provides a unique opportunity in the design of complex nanoscale patterns such as Archimedean tilings that are not accessible from linear ABC terpolymers. In this work, the synthesis and the self-assembly of 3-miktoarm star terpolymers, namely, polystyrene-arm-poly(2-vinylpyridine)-arm-polyisoprene (3 mu-SPI) into Archimedean tiling patterns is described. Several 3 mu-SPI terpolymers are produced via a mid-functional PS-b-P2VP, synthesized by sequential anionic polymerization, using a 1,1-diphenylethylene bearing a tert-butyldimethylsilyl-protected hydroxyl functionality as a core molecule. PI arms with different sizes are then linked to the deprotected hydroxyl function of the core molecule via a Steglich esterification. Solvent-annealed 3 mu-SPI thin films exhibit nanoscale prisms arranged into a (4.6.12) Archimedean tiling pattern. Depending on the size of the low etch-resistant PI arm and the solvent selected to promote the self-assembly of 3 mu-SPI thin films, the voided columns occupy the square or decagonal sites of the (4.6.12) pattern. The use of this (4.6.12) tiling produced for the first time from self-assembled 3 mu-ABC thin films can be a promising route to build 2D photonic crystals having complete photonic band gaps, where the light propagation is completely prohibite

XPS analysis of maleimide linker and peptide modified surfaces.

<p>C1s and N1s high resolution spectra of the EO₇-maleimide and EO₇-MSH surfaces.</p

The surfaces used in this study.

<p>Schematic depiction of bare gold (A) before and (B) after modification with HS-EO₇-COOH; “EO₇-COOH” surface. After (C) activation of the carboxyl moieties with EDC/NHS, (D) the surface is functionalized with maleimide; “EO₇-maleimide” surface. Finally, (E) α-MSH is immobilized on the surface via thiol-maleimide chemistry; “EO₇-MSH” surface.</p

Soluble <i>versus</i> surface bound α-MSH.

<p>Effect of immobilized α-MSH (EO₇-MHS) on LPS induced endothelial IL-6 production compared to cells re-plated onto culture dishes in culture medium containing either no soluble α-MSH (Control) or soluble α-MSH in concentration ranging from 0.2 nM to 10 μM. Error bars represent standard deviations. A Bonferroni test relative to EO₇-MSH vs. other treatments was performed. Differences were considered significant for p<0.01 and marked with an asterisk. The number of replicates is n = 5.</p

HUVEC adhesion.

<p>(A) Epifluorescence images of Endothelial cells that were re-plated onto bare gold, EO₇-COOH, EO₇-MSH surfaces and culture dish (control) in culture medium containing 1μg/mL lipopolysaccharide (LPS+) or normal culture medium (LPS-). Cell were stained for actin (green) and nuclei (blue). (B) The fluorescence images were analyzed to determine the average number of adherent cells per mm² after cells were adhered for 24h. Error bars represent standard deviations. A Bonferroni test relative to EO₇-MSH LPS+ vs. other surfaces was performed. Differences were considered significant for p<0.01 and marked with an asterisk. The number of replicates is n = 5.</p

Experimental atomic composition (%) obtained by XPS.

<p>Experimental atomic composition (%) obtained by XPS.</p

Surface bound α-MSH <i>versus</i> other surfaces.

<p>IL-6 production of endothelial cells that were re-plated onto bare gold, EO₇-COOH, EO₇-MSH surfaces and culture dish (control) in culture medium containing 1μg/mL lipopolysaccharide (LPS+) or normal culture medium (LPS-). Error bars represent standard deviations. A Bonferroni test relative to EO₇-MSH LPS+ vs. other LPS+ surfaces was performed. Differences were considered significant for p<0.05 and marked with an asterisk. Another post-hoc test comparing EO7-MSH LPS- to other LPS- surfaces was performed. Differences were considered significant for p<0.05 and marked with a section sign. The number of replicates is n = 5.</p