Methacrylic polymers bearing side-chain permanent dipole azobenzene chromophores spaced from the main chain by chiral moieties, 3 a Synthesis and chiroptical properties of the homopolymer of (R)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)- pyrrolidine and of copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)- pyrrolidine

Abstract The optically active photochromic homopolymer deriving from radical polymerization of the monomer (R)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)- pyrrolidine, containing a chiral group of one prevailing configuration interposed between the methacrylic moiety and the photochromic azoaromatic chromophore, has been synthesized and characterized. Copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)pyrrolidine have also been prepared in order to evaluate the effect on the overall optical activity of side chain chiral groups of opposite configuration in various ratios. The spectroscopic and chiroptical properties in solution of the polymeric derivatives have been assessed

Serum Albumin Is Inversely Associated With Portal Vein Thrombosis in Cirrhosis

We analyzed whether serum albumin is independently associated with portal vein thrombosis (PVT) in liver cirrhosis (LC) and if a biologic plausibility exists. This study was divided into three parts. In part 1 (retrospective analysis), 753 consecutive patients with LC with ultrasound-detected PVT were retrospectively analyzed. In part 2, 112 patients with LC and 56 matched controls were entered in the cross-sectional study. In part 3, 5 patients with cirrhosis were entered in the in vivo study and 4 healthy subjects (HSs) were entered in the in vitro study to explore if albumin may affect platelet activation by modulating oxidative stress. In the 753 patients with LC, the prevalence of PVT was 16.7%; logistic analysis showed that only age (odds ratio [OR], 1.024; P = 0.012) and serum albumin (OR, -0.422; P = 0.0001) significantly predicted patients with PVT. Analyzing the 112 patients with LC and controls, soluble clusters of differentiation (CD)40-ligand (P = 0.0238), soluble Nox2-derived peptide (sNox2-dp; P < 0.0001), and urinary excretion of isoprostanes (P = 0.0078) were higher in patients with LC. In LC, albumin was correlated with sCD4OL (Spearman's rank correlation coefficient [r(s)], -0.33; P < 0.001), sNox2-dp (r(s), -0.57; P < 0.0001), and urinary excretion of isoprostanes (r(s), -0.48; P < 0.0001) levels. The in vivo study showed a progressive decrease in platelet aggregation, sNox2-dp, and urinary 8-iso prostaglandin F2 alpha-III formation 2 hours and 3 days after albumin infusion. Finally, platelet aggregation, sNox2-dp, and isoprostane formation significantly decreased in platelets from HSs incubated with scalar concentrations of albumin. Conclusion: Low serum albumin in LC is associated with PVT, suggesting that albumin could be a modulator of the hemostatic system through interference with mechanisms regulating platelet activation

Search for lightly ionizing particles with the MACRO detector

A search for lightly ionizing particles has been performed with the MACRO detector. This search was sensitive to particles with charges between 1/5e and close to the charge of an electron, with beta between approximately 0.25 acid 1.0. Unlike previous searches both single track events and tracks buried within high multiplicity muon showers were examined. In a period of approximately one year no candidates were observed. Assuming an isotropic flux, for the single track sample this corresponds to a 90%, C.L. upper flux limit Phi less than or equal to 9.2 x 10(-15) cm(-2) s(-1) sr(-1)

CHIROPTICAL PROPERTIES OF AZOBENZENE DIMERS

Photochromic polymers have received considerable attention for their potential advanced technological applications (optical data storage, holographic memories, waveguides, chemical photoreceptors, etc.)1,2. Recently we have observed3 that it is possible to photomodulate the chiroptical properties of thin films of chiral photochromic polymers, bearing in the side-chain both a chiral group of one single configuration and the trans-azoaromatic moiety, by irradiation with circularly polarized (CP) light of one single L or R rotation sense. This unexpected new phenomenon seems to open new possibilities for the use of azobenzene containing materials as chiroptical switches, besides of the usual applications in optics. With the aim to delve into this phenomenon, we have retained of interest to study dimeric derivatives having moieties of opposite absolute configurations (Fig. 1) which correspond to the smallest section of polymer where interchromophore interactions can be present. Their CD spectra, both in solution and in the solid state, are characterized by strong exciton couplets (about one third of the signal intensity measured for the corresponding polymer) which are the mirror image of each other. In this work we present the preliminary results on the photomodulation of the chiroptical properties these oligomeric compounds dispersed in a PMMA matrix, by irradiation with CP- or EP-light. Fig. 1: Structure of investigated dimeric models and CD spectra of a film on fused silica as prepare (─) and after irradiation with EP-L (--). The financial support by Consortium INSTM (FIRB2001 ‘RBNE01P4JF’) is gratefully acknowledged. [1] S. Xie, A. Natansohn, P. Rochon, Chem. Mater., 1995, 5, 403. [2] T. Todorov T, L. Nikolova, N. Tomova, Appl. Opt., 1984, 23, 4588. [3] L. Angiolini, R. Bozio, A. Daurù, L. Giorgini, D. Pedron, G. Turco, Chem. Eur. J., 2002, 8, 4241

Methacrylic polymers bearing side-chain permanent dipole azobenzene chromophores spaced from the main chain by chiral moieties, 3 a Synthesis and chiroptical properties of the homopolymer of (R)-3-methacryloyloxy-1-(4’-nitro-4-azobenzene)- pyrrolidine and of copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4’-nitro-4-azobenzene)- pyrrolidine

Abstract The optically active photochromic homopolymer deriving from radical polymerization of the monomer (R)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)- pyrrolidine, containing a chiral group of one prevailing configuration interposed between the methacrylic moiety and the photochromic azoaromatic chromophore, has been synthesized and characterized. Copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)pyrrolidine have also been prepared in order to evaluate the effect on the overall optical activity of side chain chiral groups of opposite configuration in various ratios. The spectroscopic and chiroptical properties in solution of the polymeric derivatives have been assessed