Combined absorption of light in the process of photoactivation of biosystems

The light-oxygen effect consists in a direct excitation of molecular oxygen dissolved in aqueous media of biosystems by the light; it provides the possibility to use lasers for therapeutic purposes. The wavelength of the used light should strictly correspond to the oxygen absorption bands. However, laser therapy also makes use of lasers emitting at 0.89 μm (outside the known oxygen bands), which suggests the action of a new photoreceptor. Here we argue that this mechanism of photoreception is a modification of the light-oxygen effect involving the absorption of photon simultaneously by the oxygen molecule and O-H stretch of the H₂0 molecule of liquid water.     

Brauer characters with cyclotomic field of values

It has been shown in an earlier paper [G. Navarro, Pham Huu Tiep, Rational Brauer characters, Math. Ann. 335 (2006) 675-686] that, for any odd prime p, every finite group of even order has a non-trivial rational-valued irreducible p-Brauer character. For p=2 this statement is no longer true. In this paper we determine the possible non-abelian composition factors of finite groups without non-trivial rational-valued irreducible 2-Brauer characters. We also prove that, if p≠q are primes, then any finite group of order divisible by q has a non-trivial irreducible p-Brauer character with values in the cyclotomic field Q(exp(2πi/q)).     

Microdeformation behavior in nanotemplated epoxy thermosets: A study with in situ tensile deformation technique in transmission electron microscopy

Microdeformation behavior in nanostructured block copolymer‐toughened epoxy resins, or templated epoxy thermosets, was studied using an in situ tensile deformation technique performed directly in a transmission electron microscope. The observed microdeformation modes were found to correlate well with the macroscopic mechanical properties of the materials. In the order of decreasing macroscopic fracture toughness, the microdeformation modes were observed to change from large uniform plastic deformation over an extensive area, to localized plastic deformation bands, to little plastic deformation observed in the most brittle material. A similar trend was also observed when samples of the same material were tested at different temperatures, reflecting changes in the deformation mechanism as a function of temperature. Structural defects were observed in nanotoughening phases when plastic deformation was observed. The implication of the observed microdeformation modes to the macroscopic toughening mechanisms is discussed in the context of the micromorphology of the nanometer sized toughening phases and parameters of the epoxy matrix chemistry such as bromination, molecular weight, and interfacial miscibility. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 393–406, 2009     

The n-order iterative schemes for a nonlinear Kirchhoff-Carrier wave equation associated with the mixed inhomogeneous conditions

In this paper, a high-order iterative scheme is established in order to get a convergent sequence at a rate of order N(N?1) to a local unique weak solution of a nonlinear Kirchhoff-Carrier wave equation associated with mixed nonhomogeneous conditions - the boundary conditions are Dirichlet in one part and Robin in other part of boundary. On the other hand, some numerical results were presented.     

Delaminated zeolite‐catalysed synthesis of high‐molecular weight polycarbosilane as a low shrinkage SiC precursor

A polycarbosilane (PCS) with a higher number–average molecular weight (2710 vs. 1570), and hence with a higher ceramic yield (74 vs. 68%), compared to a commercial Nipusi type S PCS has been synthesized via the catalytic decomposition of polydimethylsilane at 400 °C using H‐ITQ‐2, a delaminated zeolite with a very high external surface area, as a solid acid. The silicon carbide film fabricated using this PCS was found to show a much lower level (16 vs. 39%) of shrinkage than the commercial PCS‐derived film, together with better mechanical properties, suggesting the potential of its preceramic polymer to produce robust ceramic coatings. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 725–732, 2008     

Synthesis,photopolymerization, and adhesive properties of new bisphosphonic acid monomers for dental application

Four new monomers, 3‐(N‐methylacrylamido)propylidenebisphosphonic acid, 3‐(N‐propyl‐acrylamido)propylidenebisphosphonic acid, 3‐(N‐hexylacrylamido)propylidenebisphosphonic acid, and 3‐(N‐octylacrylamido)propylidenebisphosphonic acid, have been synthesized in good yields and fully characterized by ¹H, ¹³C, ³¹P NMR, and HRMS. The copolymerization of these monomers with N,N′‐diethyl‐1,3‐bis(acrylamido)propane (DEBAAP) has been investigated with differential scanning calorimetry. These mixtures show a higher reactivity than DEBAAP. New self‐etch dental primers, based on these acrylamide monomers, have been formulated. Dentin shear bond strength measurements have shown that primers based on these bisphosphonic acids assure a strong bond between the tooth substance and a dental composite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5258–5271, 2009     

Spectroscopic studies on the protonation of Schiff bases

This short review concerns the protonation of Schiff bases by halogenic or carboxylic acids with a bias toward the chromophore of visual and bacterial rhodopsins. It is pointed out that the weak acids available in these pigments could not protonate the retinyl Schiff base 100% and that a supporting mechanism is needed to achieve full protonation. Our Fourier transform infrared studies both at room and low temperatures relating to this problem are summarized, and the propable role of water is emphasized.     

Automated column-switching high-performance liquid chromatographic determination of flumequine and oxolinic acid in extracts from fish

Two methods for automated analysis of extracts from edible muscle tissue of Atlantic salmon are described. Oxolinic acid and flumequine are extracted with phosphate buffer pH 9, and the extracts are analysed by high-performance liquid chromatography using a column-switching system. One method applies on-line concentration and clean-up of the extracts on a precolumn packed with polystyrene-divinylbenzene. This method was useful for the analysis of oxolinic acid and flumequine in the microgram/g range. The other method was based on on-line dialysis and concentration of the dialysate on the polymeric precolumn. This method was shown to be a reliable method for residue analysis, and the limit of detection was 2 ng/g for oxolinic acid and 3 ng/g for flumequine with fluorescence detection.