Theoretical studies on structure and mechanism of vanadium haloperoxidases

Gratitude is offered where it is due, and foremost is to my advisor Prof. Dr. Winfried Plass whose continued support and guidance in all the matters scientific put me in a position to present this work. Particular is the appreciation for his endless patience which helped me discover my own eccentricities. I feel overwhelmingly indebted to BBG and all the members of our family for their patience during my long stay abroad. That I took so long to return is my failing. That they still own me is their magnanimity. Greatly acknowledged are the contributions of my colleague Dr. Axel Buchholz towards my handling of matters of which I had little knowledge and no experience, i.e. living in Germany, understanding the vogonic poetry of German officialdom and moving from Siegen to Jena. Besides, his help in solving occasional computer hardware problems enabled my research work to run smoothly. Special thanks to my former Rumanian colleague Dr. Simona Nica for giving the semblance of social existence to what was a secluded life in Siegen. During her stay in AG Plass, she was always kind and helpful. The memorable conversations we had, covered a wide range of topics from latest scandals (from anywhere) to Schopenhauer. Particularly, her aversion towards agreeing on almost anything made the conversations much more enjoyable (and explosive)

Imposter Syndrome - 2022

Graphite and Posca on Paper 11”x14” Instructor: Brenda McKinney, Design I (2D)https://digitalcommons.collin.edu/fallstudent2022/1035/thumbnail.jp

A novel spectrophotometric determination of atenolol using sodium nitroprusside

51-54A simple, sensitive and new spectrophotometric method has been developed for determination of atenolol, a cardiovascular drug. Proposed method is based on deamination of atenolol in basic media, followed by addition of sodium nitroprusside to generate a coloured complex that absorbs at 495 nm. It gave following values: Beer’s law, 0.5-30 µg ml-1; molar absorptivity, 3.01×105 l.mol-1.cm-1; limit of detection, 0.0107 µg ml-1; and limit of quantification, 0.0358 µg ml-1. It was successfully employed for determination of active ingredient concentration in commercial formulations of atenolol

Preparation, morphology and sonication time dependence of silver nanoparticles in amphiphilic block copolymers of PEO with polystyrene or PMMA

Composite materials comprising arrays of silver nanoparticles in amphiphilic copolymers have been prepared by sonochemically enhanced borohydride reduction of precursor silver nitrate (AgNO3). The precursor was incorporated into the cores of polymeric micelles formed from block copolymers of polystyrene (PS) or poly(methyl methacrylate) (PMMA) with poly(ethylene oxide) (PEO). The copolymers were synthesised with varying hydrophobic block lengths from a PEO macroinitiator by atom transfer radical polymerization (ATRP). UV/visible spectroscopy was used to confirm the formation of elemental silver and the effect of sonication time on the appearance of the silver nanoparticles was determined. The growth was faster than when gold nanoparticles are formed in comparable block copolymers. Nanoparticles formed in copolymers with PMMA blocks were more stable to agglomeration than when polystyrene was used. Electron microscopy revealed the morphology of the nanocomposites which confirmed that both block copolymers are vehicles for the formation of well-defined films containing nanoparticulate silver. However, AgNP formation shows some significant differences from previous reports of gold NP containing materials formed under similar conditions

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

4′-Azulenyl-substituted terpyridines were efficiently synthesized following the Kröhnke methodology via azulenylchalcone intermediates. These azulenyl-containing terpyridines showed fluorescent emission with a fluorescence quantum yield varying from 0.14, in the case of parent terpyridine, to 0.64 when methyl groups are grafted on the azulenyl seven-membered ring. According to the crystal structures and TDDFT calculations, different twisting of the aromatic constituents is responsible for the observed fluorescent behavior. The electrochemical profile contains one-electron oxidation/reduction steps, which can only be explained on the basis of the redox behavior of the azulene unit. The ability of the 4′-azulenyl 2,2′:6′,2″-terpyridine to bind poisoning metal cations was studied by UV–vis titrations using aqueous solutions of Hg(II) and Cd(II) chlorides as illustrative examples