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Two series of click chemistry assisted alkoxymethyl-1H-[1,2,3]-triazol-1-yl containing side-chain liquid-crystalline polymethacrylates were synthesized by free radical polymerization technique. Mesogen was linked to backbone through various spacer units. Monomers and polymers were characterized by FT-IR, 1H and 13C-NMR spectral techniques. Thermal stability of polymers was confirmed by thermogravimetric analysis. Mesomorphic property and phase transition temperature of polymers were analysed by differential scanning calorimetry and polarized optical microscopy. Phase transition temperature and mesomorphic property of polymers with respect to insertion of polar alkoxy group on terminal triazole ring and spacer length between backbone and mesogen were investigated. Polymers exhibited grainy like textures under polarized optical microscopy. Spacer length between mesogen and backbone alters phase transition temperature of the polymers.

The oxazole and indole based heterocyclic photochromic fulgides were synthesized from their corresponding fulgenic acid derivatives by clay catalysed microwave irradiation methodology. Improved yields of fulgides were observed by the microwave irradiation method as compared other chemical methods employed so far. The proportions of clay (montmorillonite KSF) and isopropenyl acetate play a key role in increasing the yields of fulgides.

Azobenzene-based monomers and their polymers containing donor or acceptor groups at terminal positions have been synthesized. The liquid crystalline (LC) mesophase stability of one type of polymer and mixtures of donor or acceptor substituted polymers have been investigated. Mesophase formation and stability of the mixtures were studied using differential scanning calorimetry (DSC) and a hot-stage optical polarizing microscope (HOPM). The mesophase stability of the mixtures was better than those of the individual components. Binary mixture studies of acceptor monomers (a) and donor monomers (d) show that the pure low molecular weight compounds did not form any molecular aggregates and failed to show LC properties, whereas the mixture of donor substituted azobenzene and acceptor substituted azobenzene exhibits LC property. In the case of polymers, the individual acceptors (A) or donors (D) exhibit LC property, and their mixture stabilizes the crystallinity of the mesophase. The results of correlation studies of various proportions of mixtures of a/d and A/D with regard to LC properties and their mesophase stabilities are presented

Three series of side chain liquid crystalline polymers containing terminally substituted biphenyl cinnamoyl esters were synthesized and characterized. The para position in the cinnamoyl group was connected with polymer backbone through various even numbers of methylene spacers. The terminal electron acceptor and donor substituted biphenyl groups were linked to cinnamoyl group through ester linkages. Polarizing microscopic and DSC studies confirm the formation of thermotropic mesophase up on heating. All the polymers exhibited nematic/grainy mesophases. The TGA and DSC studies showed that the nature of the terminal substituents have significant effect on mesophase temperatures as well as in thermal stability of these liquid crystalline polymers. UV light promoted photocrosslinking studies reveal that the clear involvement on photocrosslinking efficiency, although they are linked to the olefinic bond of cinnamoyl group through their ester linkage. It is observed that electron-donating group accelerate the photocrosslinking rate, while acceptor group retard the phase of the reaction on the other hand, the unsubstituted polymers show an intermediate rate.

Background: The cataract surgeries are usually done in elderly patients under monitored anaesthesia care with or without sedation. Dexmedetomidine is a non-opioid sedative and analgesic and is devoid of respiratory depression. The objective of this present study is to evaluate the sedative effects of low dose dexmedetomidine infusion for unilateral cataract surgery. The patient and surgeon satisfaction scores were also recorded. Methods: Sixty patients scheduled for unilateral cataract surgery were randomly assigned to two groups: Group 1 receiving dexmedetomidine 0.5mcg/kg diluted in 100ml normal saline infusion over 15min while group 2 received normal saline. The patients in both the groups received premedication with alprazolam 0.5mg two hours prior to surgery. The hemodynamics, sedation score, patient and surgeon satisfaction scores and any adverse effects were recorded. Ramsay sedation score (RSS) of 3 was kept as a satisfactory sedation for the patient. Results: All the patients in group 1 achieved RSS of 3 while in group 2 only 47% of patients reached the target score. The patient and surgeon satisfaction scores were better with group 1. There was a significant fall in heart rate and blood pressure between 15 and 25 min after dexmedetomidine infusion. In group 1, two patients had bradycardia and four patients developed hypotension which was easily manageable. Conclusion: Dexmedetomidine, when administered as a low dose infusion provides reliable sedation and is a useful anaesthetic adjuvant for monitored anaesthesia care in cataract surgery. The patient and surgeon satisfaction scores were also better with dexmedetomidine infusion. Keywords: Cataract, Dexmedetomidine, Monitored anaesthesia care, Patient and Surgeon satisfaction scores, Sedation