A novel photoactive, liquid‐crystalline, hyperbranched benzylidene polyester (PAHBP) was synthesized from a dilute solution of an A2 photoactive monomer [bis(4‐hydroxybenzylidene)‐4‐phenyl cyclohexanone] and a B3 monomer (1,3,5‐benzene tricarboxylic acid chloride) by the solution polycondensation method in the presence of pyridine as a condensing agent. PAHBP was thoroughly characterized by Fourier transform infrared, 1H and 13C NMR, ultraviolet–visible spectrometry, and gel permeation chromatography. The inherent viscosity of the polymer was 0.35 dL/g in tetrahydrofuran. The degree of branching was 0.53, which confirmed the branched architecture of the polymer. Furthermore, thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy were used to examine the thermal stability and thermotropic liquid‐crystalline properties of the hyperbranched polyester. The polymer exhibited a nematic mesophase over a wide range of temperatures. The photoreactivity of PAHBP was studied by photolysis under ultraviolet light. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 53–61, 2006

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Photoactive hyperbranched benzylidene liquid-crystalline polyester (PAHBP) and photoactive linear benzylidene liquid-crystalline polyester (PALBP) were synthesized by solution polycondensation with pyridine as an acid acceptor. PAHBP and PALBP were thoroughly characterized with Fourier transform infrared, 1 H and 13 C NMR, ultraviolet-visible spectrophotometry, fluorescent spectrophotometry, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, and polarized optical microscopy. Both polymers exhibited nematic mesophase. The glasstransition temperature and liquid-crystalline isotropic temperature of PAHBP were higher than those of PALBP. During photolysis under ultraviolet light, both polymers underwent an intermolecular photocycloaddition reaction, and the photoactivity of PAHBP was faster than that of PALBP; this was further confirmed by photoviscosity studies. PALBP and PAHBP were fluorescent in nature. An increase in the fluorescence intensity with the time of ultraviolet-light irradiation was observed for both PAHBP and PALBP. The rate of increase in the fluorescence intensity of the linear analogue (PALBP) was higher than that of the hyperbranched polymer (PAHBP). This behavior could be attributed to the attainment of better planarity in the case of the linear one but not in the case of PAHBP because of the rapid crosslinking of PAHBP leading to an irregular architecture. This behavior was further confirmed by the calculation of the steric energy from corresponding model compounds. V V C 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: [3986][3987][3988][3989][3990][3991][3992][3993][3994] 2006

Bisbenzylidene cycloalkanone [BBCA], a versatile photo-active molecule, has already shown its potential for applications in biology, chemistry, materials science and technology. The molecule possesses the dual nature of a photo-active molecule and a mesogenic unit. It was studied as such for medical applications and by incorporating it into polymer architectures for harnessing its properties as a photo-active as well as a mesogenic unit. It was incorporated into almost all kinds of polymer architectures from polyester to polyimide. The special features of the polymer bearing this unit are high thermal stability, photo-curing ability (for adhesives, photo-resists, holography), electronic conductivity, fluorescence, etc. Even during the past decades progress was made mostly in the methods of synthesis and structural understanding of these polymers, the functional understanding and application of these polymers are still in their infancy. Quite recently, bisbenzylidene cycloalkanone polymers (linear and hyperbranched) have been reported by our group. The hyperbranched polymers address some problems regarding the solubility and quick photo-response of bisbenzylidene polymers. We discuss the state-of-the-art of this multi-disciplinary BBCA molecule and BBCA containing polymers reported to date. We believe this article will be very useful as the progress in science and technology concerning this molecule is rather slow. Our aim is to bring together details of the work reported so-far and its significance that will be useful to the scientific community.

Malignant pleural mesothelioma (MPM) is a rapidly fatal disease whose diagnosis, particularly through less invasive techniques such as analysis of pleural effusion, can be challenging. Currently, a commercially available diagnostic test based on microRNA (miRNA) expression patterns is purported to distinguish between mesothelioma and lung adenocarcinoma. Yet, the biological basis of this technology has not been reported in the literature, and little research has been aimed at determining how differential miRNA expression contributes to the differences in pathogenesis between these diseases, both of which can be caused by asbestos exposure. We sought to illuminate the molecular differences between mesothelioma and lung adenocarcinoma by using miRNA microarrays to identify patterns in the most differentially expressed miRNAs. From this, we identified a panel of miRNAs, including members of the miR‐200 gene family, that were all downregulated in MPM compared to lung adenocarcinoma. Using the more sensitive detection method of quantitative RT‐PCR on an independent series of tumors, we validated the specificity of these alterations in 100 MPMs and 32 lung adenocarcinomas. Statistical analysis reveals that these miRNAs exceed the current recommendations for biomarkers and could greatly aid in the differential diagnosis. Further examination led us to predict that they act as redundant regulators of wnt signaling and suggests a role for this pathway in tumor progression. This research points to novel approaches using miRNAs whose decreased expression is unique to mesothelioma as potentially suitable for rapid diagnosis and reveals prospective new targets for the treatment of this deadly disease.