Comparison of injection lignocaine (preservative free) 1.5 mg/kg i.v with oral pregabalin 150 mg for attenuation haemodynamic response to laryngoscopy and tracheal intubation.

Endotracheal intubation is sine quo non for safe conduct of general anaesthesia. Pregabalin, an anticonvulsant drug is being studied for control of haemodynamic response to laryngoscopy and intubation. Some authors have found that pregabalin 150 mg orally attenuates the haemodynamic response to laryngoscopy. The purpose of the present study was to compare injection lignocaine (preservative free) i.v. and oral pregabalin for attenuation of haemodynamic response to laryngoscopy and intubation. The study consisted of 60 patients of ASA class I, divided into two groups of 30 each. Group I received injection lignocaine (preservative free) 1.5 mg/kg i.v., 3 minutes prior to laryngoscopy. Group II received oral pregabalin 150 mg capsule 1 hour prior to induction. The parameters recorded were heart rate, systolic BP, diastolic BP, mean BP and rate pressure product was calculated at baseline before induction and at 1, 3 and 5 minutes following laryngoscopy. The data obtained was analysed using unpaired "t" test. Lignocaine was more effective than pregabalin in controlling the heart rate at one minute following laryngoscopy. Pregabalin was more effective than lignocaine in controlling diastolic blood pressure at 1, 3 and 5 minutes following laryngoscopy, and mean arterial pressure at land 3 minutes following laryngoscopy. There was no difference between two groups when systolic BP and rate pressure product were compared. Lignocaine (preservative free) thus, exerts better control over heart rate and pregabalin exerts better control over diastolic and mean blood pressure following laryngoscopy.

Solvent mixture induced self assembly of a terthiophene based rod-coil block co-oligomer.

We describe the synthesis and self-assembly of a terthiophene-oligostyrene based block co-oligomer Ter-OSa. While the self-assembly of block copolymers is normally achieved using block-selective solvents, tetrahydrofuran (THF) is a good solvent for both terthiophene and oligostyrene blocks. The self-assembly in this case arises with the nonsolvent (H(2)O) in THF/H(2)O mixtures. The absorption spectra showed a blue shift and fluorescence spectra showed quenching of fluorescence with increasing water content indicating that the Ter-OSa self-assembled to form H-aggregates. The morphology was studied using scanning electron microscopy. Depending upon the amount of water the Ter-OSa undergoes morphological transition from hollow to rigid spheres. However at higher water content the Ter-OSa formed large spheres from the fusion of smaller spheres. A mechanism of morphological transition from hollow spheres to rigid spheres is proposed.

Facile Preparation of Nanogels Using Activated Ester Containing Polymers.

A facile methodology to prepare water-dispersible nanogels based on pentafluorophenyl acrylate and polyethylene glycol methacrylate random copolymer and diamine cross-linkers has been developed. Cross-linking reaction was characterized by FTIR and 19F NMR. We show that those nanogels : (i) are water-dispersible; (ii) can conveniently encapsulate lipophilic guest molecules; (iii) can be prepared with different nanosizes; (iv) are engineered to allow for surface decoration with additional functional groups.

Photophysical investigation into the self-organization in pyrene-based urethane methacrylate comb polymer.

A side chain urethane methacrylate polymer with pendant pyrene units was synthesized and investigated for its self-organizing process in solution by UV-vis and fluorescence spectra and in film by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence microscopy. The polymer exhibited excimer emission centered at 476 nm, even at very dilute concentrations (10(-6) M) as a consequence of the polymer design with pendant pyrene units on every side chain. A change in aggregation pattern was observed upon increasing the concentration to 10(-4) M. New red-shifted peaks appeared in the UV-vis absorption spectra and the I(E)/I(M) ratio, and the peak I/peak III ratio showed a break around 10(-4) M, suggesting formation of stable ground state aggregates. This was further confirmed by the SEM, TEM, AFM and fluorescence microscope studies, which showed the formation of vesicles in THF and giant spherical aggregates in THF/H(2)O. The change in pattern of aggregate formation with concentration also coincided with a sudden increase in the intensity of the hydrogen bonded urethane N-H peak with concentration as recorded by solution FT-IR studies in THF.

Self-organization-induced three-dimensional honeycomb pattern in structure-controlled bulky methacrylate polymers: Synthesis, morphology, and mechanism of pore formation.

Here we report, for the first time, a novel molecular design for three-dimensional honeycomb structures through a self-organization of hydrogen-bonded bulky anchoring group in a methacrylic polymer backbone. The polymerizable monomer design includes a methacrylic double bond linked to various hydrophobic anchoring units such as ethane, n-decane, tricyclodecane (TCD), and adamantane via a hydrogen-bonded cycloaliphatic urethane linkage. The structures of the polymers were confirmed by nuclear magnetic resonance (NMR) and the molecular weights of the polymer were determined by gel permeation chromatography (GPC). The methacrylate polymers having tricyclodecane and adamantane bulky anchoring groups self-organized to produce three-dimensional honeycomb patterns in tetrahydrofuran-water solvent mixture at ambient conditions, whereas its linear analogues (ethane, n-decane) failed to produce any micropattern. The scanning electron microscopy (SEM) analysis of the above-prepared polymer films revealed that the structure of the polymer played a major role in the formation of the honeycomb patterns. The solution Fourier transform infrared (FTIR) measurements confirmed that the bulky tricyclodecane and adamantane polymers have strong hydrogen-bonding interaction compared to that of their linear analogues, which is the driving force for the micropatterns. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) analysis of the bulky polymers revealed that the polymers exist as vesicles or micelles in the solution, which leads to the formation of the honeycomb pattern. The honeycomb pattern formation in the bulky polymer systems suggests that two cooperative factors such as hydrogen-bonding interaction and hydrophobicity of bulky anchoring units are necessary to induce three-dimensional honeycomb structures. To investigate the effect of molecular weights and its distribution on the self-organization process, both benzoyl peroxide (BPO) initiated free radical and atom transfer radical polymerization (ATRP) techniques were employed for the polymerization. Micropores formed irrespective of differences in molecular weight and polydispersity index (PDI); however, the pore size distribution was influenced by both molecular weights and PDI. Low molecular weight samples afforded polydisperse pores with the ATRP samples with more narrow PDI producing pores with large dimensions. The approach has also been investigated for polystyrene-bulky methacrylic copolymer, and the results revealed that uniform honeycomb patterns were produced for copolymers having more than 50 mol % incorporation of bulky units.