Kinetics of Polymerization of Methyl Methacrylate initiated by AIBN in the Presence of Acetophenone

The present investigation aims at estimating the retarding effect of acetophenone in the polymerization of methyl methacrylate initiated by α,α' -azobisisobutyronitrile in the temperature range of 50 to 80°C. The results are interpreted in terms of Tüdös kinetic parameter (β). The effects of varying concentrations of substrate, monomer, initiator, and salts have been investigated. A suitable reaction scheme and rate expression have been suggested on the basis of the experimental findings, and another kinetic parameter (K) to represent the reactivity of acetophenones toward the polymer radical has been obtained graphically.     

Profiling primaquine metabolites in primary human hepatocytes using UHPLC‐QTOF‐MS with 13C stable isotope labeling

Therapeutic efficiency and hemolytic toxicity of primaquine (PQ), the only drug available for radical cure of relapsing vivax malaria are believed to be mediated by its metabolites. However, identification of these metabolites has remained a major challenge apparently due to low quantities and their reactive nature. Drug candidates labeled with stable isotopes afford convenient tools for tracking drug‐derived metabolites in complex matrices by liquid chromatography‐tandem mass spectrometry (LC‐MS‐MS) and filtering for masses with twin peaks attributable to the label. This study was undertaken to identify metabolites of PQ from an in vitro incubation of a 1:1 w/w mixture of ¹³C₆‐PQ/PQ with primary human hepatocytes. Acquity ultra‐performance LC (UHPLC) was integrated with QTOF‐MS to combine the efficiency of separation with high sensitivity, selectivity of detection and accurate mass determination. UHPLC retention time, twin mass peaks with difference of 6 (originating from ¹³C₆‐PQ/PQ), and MS‐MS fragmentation pattern were used for phenotyping. Besides carboxy‐PQ (cPQ), formed by oxidative deamination of PQ to an aldehyde and subsequent oxidation, several other metabolites were identified: including PQ alcohol, predictably generated by oxidative deamination of PQ to an aldehyde and subsequent reduction, its acetate and the alcohol's glucuronide conjugate. Trace amounts of quinone‐imine metabolites of PQ and cPQ were also detected which may be generated by hydroxylation of the PQ/cPQ quinoline ring at the 5‐position and subsequent oxidation. These findings shed additional light on the human hepatic metabolism of PQ, and the method can be applied for identification of reactive PQ metabolites generated in vivo in preclinical and clinical studies. Copyright © 2013 John Wiley & Sons, Ltd.     

Thermal properties of textile fabrics

Objective evaluation techniques were used in this study of thermal properties of textile fabric. The Alambeta, P tester, and Togmeter measure the passages of air which were used for evaluation of the physiological properties. Fibrous materials were prepared in the form of textile knitting fabric COOLMAX. It is clear from the measurement that there are considerable differences in the results of measurement with described methods. Device Alambeta is convenient for the measurement and evaluation of various thermal properties. Finally, it can be concluded that this field of measurements is developing and will be the subject of further research of other methods, more suitable for measurement of the various characteristics.     

Molecularly imprinted polyaniline-polyvinyl sulphonic acid composite based sensor for para-nitrophenol detection

We report results of the studies relating to the fabrication and characterization of a conducting polymer based molecularly imprinted para-nitrophenol (PNP) sensor. A water pollutant, para-nitrophenol is electrochemically imprinted with polyvinyl sulphonic acid (PVSA) doped polyaniline onto indium tin oxide (ITO) glass substrate. This PNP imprinted electrode (PNPI-PANI-PVSA/ITO) prepared via chronopotentiometric polymerization and over-oxidation is characterized by Fourier transform infra-red spectroscopy (FT-IR), UV–visible (UV–vis) spectroscopy, contact angle (CA), scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies. The response studies of PNPI-PANI-PVSA/ITO electrode carried out using DPV reveal a lower detection limit of 1 × 10⁻³ mM, improved sensitivity as 1.5 × 10⁻³ A mM⁻¹ and stability of 45 days. The PNPI-PANI-PVSA/ITO electrode shows good precision with relative standard deviation of 2.1% and good reproducibility with standard deviation of 3.78%.     

Chromatography-Based Determination of Anabolic Steroids in Biological Fluids: Future Prospects Using Electrochemistry and Miniaturized Microchip Device

Anabolic steroids form one of the important classes of doping agents and their consumption has been found to give benefits to the athletes. Inspite of the fact that they also produce adverse effects and damage several organs and systems, their consumption is continuously increasing in competitive games. The World Anti-Doping Agency and International Olympic Committee have banned the use of anabolic steroids and several other compounds. This article focuses an over view of various chromatographic techniques commonly used for detecting anabolic steroids and their metabolites during last 3 years in human biological fluids to establish the cases of doping. The possibility of electrochemistry- and microchip-based techniques have been considered as possible techniques for future to achieve simple and fast analysis at the site of competitive games as the first tool to detect the cases of doping.     

Low-Valent Titanium Mediated Deprotection of N-Allyl/Benzyl Amines: A New Approach

A novel low-valent titanium (LVT) mediated cleavage of N-allyl/benzyl amines is reported. Regio- and chemo-selective cleavages were also observed.     

Synthesis and Spectral Studies of Some Novel 2,5,9,10-Tetrahydro [7,8-g]benzo-8-arylpyrazolo[4,5-e][1,5-b]benzoxazonine via Phase Transfer Catalysis

Treatment of 1H-4,5-dihydro-3-aryl-5-(2-hydroxyaryl)pyrazole with o-dibromoxylene under liquid-liquid phase transfer catalytic conditions using tetra-n-butylammonium hydrogen sulphate or [18]-crown-6 as PT catalyst, benzene/chloroform as organic phase and 50% aqueous potassium hydroxide as second phase, afforded novel 2,5,9,10-tetrahydro [7,8-g] benzo-8-arylpyrazolo[4,5-e] [1,5-b] benzoxazonines.     

Solvent-Free Esterification of Carboxylic Acids and Alcohols in the Presence of Silphos [PCl3-n(SiO2)n] as a Heterogeneous Phosphine Reagent

An efficient solvent-free method for the preparation of esters from various aromatic and aliphatic acids with primary, secondary, and tertiary alcohols using a heterogeneous phosphine reagent, silphos [PCl_3-n(SiO₂)_n], in good yields is reported.