Determination of three analgesics in pharmaceutical and urine sample on nano poly (3, 4-ethylenedioxythiophene) modified electrode

Three analgesics, acetaminophen, acetylsalicylic acid, and dipyrone were determined by stripping voltammetry using nanosized poly(3,4-ethylenedioxythiophene)-modified glassy carbon electrode . The cyclic voltammetric behavior of the three analgesics was studied in aqueous acid, neutral, and alkaline conditions. One well-defined oxidation peak each for acetaminophen and acetylsalicylic acid and three oxidation peaks for dipyrone were observed in the cyclic voltammograms. The influence of pH, scan rate, and concentration revealed irreversible diffusion controlled reaction. A systematic study of the experimental parameters that affect the differential pulse stripping voltammetric response was carried out. Calibration was made under maximum peak current conditions. The scanning electron microscope analysis confirmed good accumulation of the drugs on the electrode surface. The range of study for both acetaminophen, acetylsalicylic acid were 0.015–0.4 and dipyrone was 0.025–0.4 μg/ml. The lower limit of determination for both acetaminophen, acetylsalicylic acid was 0.01 μg/mL and for dipyrone was 0.02 μg/mL. The suitability of the method for the determination of the three analgesics in pharmaceutical preparations and urine samples was also ascertained.     

Speeding up thermalisation via open quantum system variational optimisation

Optimising open quantum system evolution is an important step on the way to achieving quantum computing and quantum thermodynamic tasks. In this article, we approach optimisation via variational principles and derive an open quantum system variational algorithm explicitly for Lindblad evolution in Liouville space. As an example of such control over open system evolution, we control the thermalisation of a qubit attached to a thermal Lindbladian bath with a damping rate γ. Since thermalisation is an asymptotic process and the variational algorithm we consider is for fixed time, we present a way to discuss the potential speedup of thermalisation that can be expected from such variational algorithms.     

Bioenergetics and bioremediation of contaminated soil

The microbial biodegradation of xenobiotic compounds in soil and ground water is constrained by the laws of thermodynamics. Bioremediation is being investigated in a rhizosphere environment in which higher plants provide carbon and energy to sustain the microbial population. Toluene, phenol, trichloroethylene and trichloroethane have been fed in separate experiments to a pilot scale system with alfalfa growing in sandy soil containing less than 10% of silt. It is well known that microbial populations are numerous in the root zone of healthy vegetation. Root exudates can stimulate aerobic microbial biodegradation of compounds which by themselves support growth poorly or not at all. Polynuclear aromatic compounds such as phenanthrene, anthracene, and pyrene, which are not very soluble in water, and chlorinated aliphatic hydrocarbons such as trichloroethylene are examples of compounds that can be biodegraded in the rhizosphere when root exudates are present to enhance and sustain microbial activity. Solar driven transport processes such as water and solute movements due to evapotranspiration increase the likelihood that the contaminants will come into contact with the microorganisms and be degraded. The thermodynamic and bioenergetic aspects of transport and biodegradation in the rhizosphere are examined through a review of the literature and the analysis of experimental data collected in the pilot scale system.     

Synthesis of functionalized tetrahydroisoquinolines via palladium-catalyzed 6-exo-dig carbocyclization of 2-bromo-N-propargylbenzylamines

An efficient twostep synthetic strategy for tetrahydroisoquinolines has been described. The first step involves CuI catalyzed three-component coupling reaction of terminal alkyne, aldehyde and amine that provides the requisite propargyl amine. Regio- and stereoselective palladium-catalyzed 6-exo-dig carbocyclization of propargyl amine, which provides a concise access to functionalized tetrahydroisoquinolines in good yields has been developed.     

Flaky Structured V2O5: Morphology,Formation Scheme and Supercapactive Performance

Vanadium pentoxide (V₂O₅) based electrodes for energy storage devices have captured sizeable attention in the past decade owing to their attractive physiochemical features. In the present work, flaky structured V₂O₅ was prepared using a single step hydrothermal route. The results from analytical investigations hold up well with the formation scheme proposed. The flaky morphology of V₂O₅ facilitates additional pathways for electron transport and effective ion access. When employed as a supercapacitor electrode in a neutral electrolyte, this flaky V₂O₅ electrode demonstrates a specific capacitance of 472 F g^?1. Besides, it retains maximum capacitance at higher current density confirming its good rate performance. An asymmetric type supercapacitor using flaky V₂O₅ as positive electrode and activated carbon as negative electrode exhibits specific capacitance of 69 F g^?1. This device shows energy density of 10 W h kg^?1 within the operational window of 1 V.

     

Metastable zonewidth, induction period and interfacial energy of zinc tris(thiourea) sulfate

Metastable zonewidth and induction period measurements on ZTS and ZTSP crystals are presented. The effect of pH on the solubility, metastable zonewidth and induction period has been studied. The effect of substitution of phosphate on the nucleation parameters has been presented. The interfacial energy for pure and phosphate mixed ZTS solutions at 30°C has also been estimated. There is a significant variation in the induction period and interfacial energy due to decrease in solution pH and phosphate substitution.     

Electrophilic trifluoromethylation of simple inorganic salts: a one step route to trifluoromethylnitromethane, CF3NO2

Trifluoromethylnitromethane is readily synthesized in high yield from the electrophilic trifluoromethylation of NaNO₂.     

Enolate alkylations with diethylbutadiene phosphonate-II

An effect by the cation has been observed in the reactions of aldehyde enolates with 1-diethylphosphinyl-1,3-butadiene.     

Cobalt(II) complexes of creatinine

Summary Cobalt(II) complexes of creatinine [Co(creat)₂X₂] (X = Cl, Br, I or NCS) and [Co(creat)₂X₂(H₂O)₂] (X = HCO₂, HOCH₂CO₂ or CNCH₂CO₂) have been prepared. Their i.r. spectra show an increase in (NH) of the cyclic secondary amine group, compared to free ligand (3300 cm^–1), indicating that cyclic nitrogen is involved in coordination. The thiocyanate group coordinates through nitrogen and carboxylates coordinate as univalent unidentate ligands. The electronic spectra and magnetic moments suggest a d⁷ configuration for cobalt: a tetrahedral geometry (4.4 B.M.) for halide and thiocyanate complexes, and an octahedral geometry (5.0 B.M.) for the carboxylate complexes. On heating, the ligand moiety is lost and the respective cobalt halide or cobalt carboxylate is formed, which is converted finally into Co₃O₄. There is a correlation between the high intensity electronic transitions and the polarographic half-wave potentials.     

Effect of piperidones on hydrogen permeation and corrosion inhibition of mild steel in acidic solutions

The influence of 3-methyl-2,6-diphenyl piperidin-4-one (MDPO) and 2-phenyl decahydroquinoline-4-one (PDQO) synthesised in the laboratory on hydrogen permeation and corrosion inhibition of mild steel in 1N H₂SO₄ has been studied using weight loss and various electrochemical AC and DC corrosion-monitoring techniques. Both the compounds inhibit the corrosion of mild steel in H₂SO₄. Potentiodynamic polarisation studies clearly reveal that they behave predominantly as cathodic inhibitors. The extent of decrease in hydrogen permeation current through steel surfaces has been studied by the hydrogen electropermeation technique. Double layer capacitance (C _dl ) and charge transfer resistance (R _t ) values are derived from Nyquist plots obtained from AC impedance studies. The adsorption of these compounds on mild steel surfaces from H₂SO₄ obeys Temkin’s adsorption isotherm.