The surface relief gratings (SRGs) can be generated when azo-polymer films are exposed to laser beam interference as a result of mass migration. Despite considerable research effort over the past two decades this complex phenomenon remains incompletely understood. Here we show, for the first time, the athermal photofluidisation of azo-polysiloxane films exposed to 488 nm light, directly monitored by optical microscopy. A process of surface relief erasure occurring in parallel with its inscription was also observed during laser irradiation. We therefore propose a new mechanism of SRG formation, based on three different processes: (1) the polymer photo-fluidization in illuminated regions, (2) the mass displacement from illuminated to dark regions and (3) the inverse mass displacement, from dark to illuminated regions. The mechanical properties of the films during UV light irradiation were investigated by classical rheology and, for the first time, by using amplitude modulation-frequency modulation atomic force microscopy (AM-FM AFM).

[structure: see text]. The important biological secondary messenger NO can be generated from exogenous nitrovasodilators and NO donors. Nitrate esters are nitrovasodilators and NO mimetics, believed to be biotransformed to NO in vivo. On the basis of a mechanistic hypothesis, nitrates have been synthesized that release NO at significant rates in neutral aqueous solution in the presence only of added thiol. The novel masked beta-mercaptonitrates reported (SS-nitrates), provide information on possible sulfhydryl-dependent biotransformation mechanisms for nitrates in clinical use.

Here we show the possibility to obtain azopolysiloxanes modified with nucleobases (adenine and thymine) with potential application in immobilization and nanomanipulation of biomolecules. We propose a photofluidization mechanism based on the concept of the conformational instability, which can explain the presence of the fluid state below the glass transition. The azopolymers were characterized by 1H NMR, GPC, DSC, DTG, UV spectroscopy, AFM analysis, and molecular simulations. Depending on the type of nucleobase used, the surface of the azopolysiloxane film can be structured in different ways under UV irradiation. Photoisomerization studies in solid state were carried out to demonstrate the influence of the operational conditions (presence or absence of natural visible light) on the polymeric film UV response. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4240–4248, 2007

This review gives a brief survey of synthetic inhibitors of influenza virus which have been synthesized to date. It starts with a short introduction which describes the structure and mechanism of action of influenza virus and continues with the main research directions that have been used in order to inhibit the virus. This is followed by discussion of various synthetic materials, including synthesis and antiviral properties, which that have been tested against influenza virus. The most potent inhibitory compounds proved to be polyvalent, because of their high binding affinity and steric stabilization. Finally we conclude with a brief discussion on structural characteristics, a summary, and outlook overview.

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This Review discusses the synthesis and characterization by our Group of new antibiotics belonging to the class of penicillins, cephalosporins and rifamycins with ferrocenyl and 1, 1′‐ferrocenilene residues in the molecule. As reactants for 6‐aminopenicillanic acid (6‐APA) and 7‐aminocephalosporanic acid (7‐ACA) the following were used: 1, 1‐bis(chlorocarbonyl)ferrocene, ferrocenyl sulfochloride, 1, 1′‐ferrocenylenedisulfochloride and thioglycolic acids S‐modified with ferrocene. In the synthesis of rifamycins, the hydrazides of the thioglycolic acids, S‐modified with ferrocene, were employed as nucleophilic agents. The synthesized intermediates were characterized by elemental analysis, TLC, IR, UV and 1H NMR spectra. The characterization of new antibiotics was made by TLC, IR and UV spectral analysis. Biological activity was tested on Gram‐negative and Gram‐positive bacteria. Good activity is reported towards Gram‐positive bacteria in the case of derivatives containing residues of thioglycolic acid S‐modified with ferrocene, the antibacterial activity being similar to that of amoxicillin, carbenicillin and cephalothin. All compounds are inactive towards Gram‐negative bacteria.

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