Synthesis,characterization, thermal stability and antibacterial activity of coumarin based methacrylate copolymers

Monomer of 7-methacryloyloxy-4-methylcoumarin(MAOMC) was synthesized and characterized by FTIR, 1H-NMR and 13C-NMR spectroscopy. Copolymers of MAOMC with butoxyethylmethacrylate(BOEMA) at different feed compositions were prepared by free radical solution polymerization at(70 ± 1) °C in ethylmethylketone(EMK) using benzyl peroxide(BPO) as an initiator. The copolymers were characterized by FTIR and 1H-NMR spectroscopy. Thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC) of the copolymers showed moderate thermal stability and higher Tg values. Gel permeation chromatography(GPC) was used to find out the molecular weights of the different copolymers. Antibacterial activities of the copolymers were also investigated against the selected pathogenic bacteria's. The antibacterial activity of the copolymer increases as the MAOMC content increases in the copolymer. This shows that coumarin moiety plays a very important role in the antibacterial activity.     

Preparation and Characterization of Bhant Leaves‐derived Nitrogen‐doped Carbon and its Use as an Electrocatalyst for Detecting Ketoconazole

In this study, the electrocatalytic characteristics of nitrogen‐doped carbon (NDC) prepared from Clerodendrum Infortunatum L leaves on a glassy carbon electrode (GCE) surface was evaluated with regards to its ability to detect the electroactive drug ketoconazole (KCZ). The NDC was prepared by carrying out a simple pyrolysis of dry powder of the leaves at 850 °C. The prepared NDC was characterized using field‐emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and Brunauer‐Emmett‐Teller analysis, and was then used as an electrode material. The performance of the electrochemical KCZ sensor with the NDC‐modified glassy carbon electrode (NDC/GCE) was found to be optimal when using PBS buffer at pH 3 and a concentration of 0.1 mg/ml of NDC in the conjugate with Nafion polymer. Under these conditions, the NDC/GCE displayed a KCZ detection limit of 3 μM and a linear dependence of its response on KCZ concentration over a wide range of KCZ concentrations from 47 μM to 752 μM (R²=0.9742). These results confirmed the potential of NDC as an electrocatalyst.     

The Internal Bremsstrahlung Accompanying the β-Decay from 185W

The internal bremsstrahlung (IB) spectrum accompanying the β-decay from ¹⁸⁵W radionuclide has been measured. The obtained spectrum was analyzed into its constituting gamma lines taking into account all the proper corrections. The analyzed spectrum was compared with those theoretically calculated. The experimental results for the IB probability were found to be in good agreement with theoretical calculations especially with the shape corrected modified KUB theory of Nilsson up to 357.7 keV.     

Best Proximity Points: Optimal Solutions

This article elicits a best proximity point theorem for non-self-proximal contractions. As a consequence, it ascertains the existence of an optimal approximate solution to some equations for which it is plausible that there is no solution. Moreover, an algorithm is exhibited to determine such an optimal approximate solution designated as a best proximity point. It is interesting to observe that the preceding best proximity point theorem includes the famous Banach contraction principle.     

Best Proximity Point Theorems for Some Special Proximal Contractions

This article explores some new best proximity point theorems for absolute proximal cyclic contractions and dual supreme proximal contractions which are not necessarily continuous. As a consequence of such best proximity point theorems, the famous contraction principle is elicited.     

A novel three carbon-amino grignard reagent: its use in an efficient pyrrolidine synthesis

A novel primary amino protected Grignard reagent has been developed; 2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane-1-propyl magnesium bromide 1a. Its usefulness is illustrated in the synthesis of 2-substituted pyrrolidines.     

Evaluation of the current function in linear sweep voltammetry by Pade approximation and epsilon convergence

Two procedures, viz., the epsilon convergence algorithm and Pade approximation scheme, are used to evaluate the current function values, graphical representation of the output, and verification of the model using existing data are carried out. For theoretical simulations of voltammograms, closed form of rational expressions using Pade approximant for the response of various reactions schemes involving soluble reactant and product, as well as coupled chemical process to an imposed linear scans were derived. Similarly, it was demonstrated epsilon convergence as an alternative procedure is much easier and elegant to use by an electroanalytical chemist with extreme ease.__________From Elektrokhimiya, Vol. 41, No. 4, 2005, pp. 482–500.Original English Text Copyright © 2005 by Sivakumar, Basha.This article was submitted by the authors in English.     

Best proximity point theorems for contractive mappings

This article is concerned with some new best proximity point theorems for principal cyclic contractive mappings, proximal cyclic contractive mappings, and proximal contractive mappings. As a consequence, an interesting fixed point theorem, due to Edelstein, for a contractive mapping is obtained from all those best proximity point theorems.     

Tertiary-butoxycarbonyl (Boc) – A strategic group for N-protection/deprotection in the synthesis of various natural/unnatural N-unprotected aminoacid cyanomethyl esters

A number of cyanomethyl esters of natural/unnatural aminoacids with un-protected amino functionality were synthesized because of their synthetic and medicinal importance. Critical N-Boc deprotection methods in the presence of labile (hydrolytic sensitivity) cyanomethyl functionality were screened thoroughly and it was found that readily available 4M HCl in 1,4-dioxane solution (2–4 equiv); acetonitrile, 0?°C, 2–4?h was a suitable condition. This condition was generalized and successfully applied to a variety of alkyl, alkynyl, aryl, heteroaryl, benzyl, azido, spiro amino acid cyanomethylesters irrespective of the nature of the amine (primary or secondary) and the distance between the amine and ester group to achieve final deprotected amino esters with high yield, and purity compared to other commonly known N-protecting groups (Cbz, Fmoc, Ac, Bn, Bz etc.). It was also demonstrated that N-Boc protected aminoacid cyanomethylesters are stable enough to carry out further functionalization compared to N-unprotected counterparts.