A general approach to the synthesis of second-order nonlinear optical (NLO) polyimides exhibiting high thermal stability has been developed. Several selected NLO chromophores have been incorporated into the polyimide backbone. Detailed physical studies showed that these polymers are very promising for practical applications. Three of these polyimides are soluble in common organic solvents, offering the ease of processing. High glass temperatures, around 230 °C, assure a long-term NLO stability at elevated temperatures, such as 150 °C. Low optical loss was observed for those soluble polymers. The synthetic approach is also versatile and will allow the syntheses of many other functional polymers.

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Introduction. Keratinophilic fungi are an important group of fungi that live in soil. The aim of this study was to isolate and identify keratinophilic fungi from the soil of different parks in Shiraz. Materials and Methods. A total of 196 soil samples from 43 parks were collected. Isolation of the fungi was performed by hair bait technique. The isolated colonies were identified by morphologic feature of macro- and microconidia and molecular method, using DNA sequence analysis. ITS region of ribosomal DNA was amplified and the PCR products were sequenced. Results. 411 isolates from 22 genera were identified. Fusarium (23.8%), Chrysosporium (13.13%), Acremonium (12.65%), Penicillium (12.39%), Microsporum gypseum (1.94%), Bionectria ochroleuca (1.21%), Bipolaris spicifera (1.21%), Scedosporium apiospermum (0.82%), Phialophora reptans (0.82%), Cephalosporium curtipes (0.49%), Scedosporium dehoogii (0.24%), Ochroconis constricta (0.24%), Nectria mauritiicola (0.49%), Chaetomium (0.49%), Scopulariopsis (0.24%), Malbranchea (0.24%), and Tritirachium (0.24%) were the most important isolates. Most of the fungi were isolated from the soils with the PH range of 7 to 8. Conclusion. Our study results showed that many keratinophilic fungi isolated from the parks soil are important for public health and children are an important group at a high risk of being exposed to these fungi.

To synthesize nonlinear optical polyimides exhibiting high nonlinearity and high thermal stablity, a new monomer bearing phenylenediamine and a diazo benzene-type nonlinear optical chromophore (compound 1) was synthesized and polymerized with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride. This diazo chromophore possesses a microscopic optical nonlinearity larger than either the Disperse Red 1 or DANS chromophores. Copolymerization of compound 1 and 1,4diaminophenylene with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride yielded copolyimides with higher glass transition temperatures. These polyimides exhibit large electrooptic coefficients, r33 ∼ 14-35 pm/V. The second harmonic measurements indicate long-term stability of the dipole orientation (>800 h at 100 °C) for these polyimides.