Esomeprazole is a new chromogenic reagent used for the determination of nickel (II) by direct spectrophotometric method. Esomeprazole forms a greenish yellow colouredcomplex with nickel (II) at pH 5. The method obeys Beer’s law over 0.139 – 1.394 μg mL -1 , Sandell’s sensitivity is 0.0029mg/cm 2 and molar absorptivity value (ε = 2.5 x 10 4 L mol -1 cm -1 ). The method is useful for determinatio...

It is well known that the efficiency of thermodynamic solar plants increases with the working temperature. At present the main limit in temperature upscaling is the absorber capability to withstand high temperatures. The ideal solar absorber works at high temperatures, has a low thermal emissivity and a high absorptivity in the solar spectral range . The paper reports on the high temperature em...

We present the theory, design, and realization of a polarization-insensitive metamaterial absorber for terahertz frequencies. Effective-medium theory is used to describe the absorptive properties of the metamaterial in terms of optical constants—a description that has been thus far lacking. From our theoretical approach, we construct a device that yields over 95% absorption in simulation. Our f...

A simple, sensitive, rapid, accurate and precise spectrophotometric method has been developed for the estimation of Zolpidem tartrate in bulk and pharmaceutical dosage forms. Zolpidem tartrate shows maximum absorbance at 238.5 nm with molar absorptivity of 4.4648×10lit/mol/cm. Beer’s law was obeyed in the concentration range of 2-16 μg/ml. The limit of detection and limit of quantification were...

We perform direct thermal emission calculations for three-dimensionally periodic photonic crystal slabs using stochastic electrodynamics following the Langevin approach, implemented via a finite-difference time-domain algorithm. We demonstrate that emissivity and absorptivity are equal, by showing that such photonic crystal systems emit as much radiation as they absorb, for every frequency, up ...

We describe a method for measuring the catalytic activity of alpha-amylase (EC 3.2.1.1) in serum and urine, by use of a defined substrate: 1,4-alpha, D-4-nitrophenyl maltoheptaoside. We use a phosphate buffer of pH 7.10, containing chloride as activator and alpha-glucosidase (EC 3.2.1.20) as the auxiliary enzyme. After a lag phase of 4 min at 25 degrees C or 30 degrees C, or 3 min at 37 degrees...

Dopamine and dobutamine have recently been shown to produce a negative interference in several biochemical tests that use peroxide and peroxidase to generate a chromophore. To define the chemical mechanism of this interference, we examined the effects of dopamine and dobutamine in various peroxidase-based biochemical tests. Dopamine interfered stoichiometrically with peroxidase-based tests that...

The absorption and emission problems of the brane-localized and bulk scalarsare examined when the spacetime is a (4+n)-dimensional Reissner-Nordströmblack hole. Making use of an appropriate analytic continuation, we computethe absorption and emission spectra in the full range of particle’s energy. Forthe case of the brane-localized scalar the presence of the nonzero inner ho...

Failure to account for fluorescein absorbance changes with pH may be responsible for some of the apparent non-conservative behaviour of this easily detectable tracer compound. While it is possible to calculate an accurate absorptivity value for fluorescein at every pH, this calculation is not necessary if the sample pH is increased above pH 9 before measuring the absorbance. Intense sunlight de...

Spectrophotometric method was used to evaluate the kinetic of the complex formation from the reaction between H[Ru(III)Cl2(H2EDTA)] and the modifier agent [3-(2-aminoethyl)aminopropyl] trimethoxysilane (AEATS) (μ = 0.50 mol∙dm−3 with NaCF3COO, 298.15 K), in pseudo-first order conditions. These studies showed that the reactions are successives producing several species influenced by the concentr...