Phytochemical screening of Nepeta cataria extracts and their in vitro inhibitory effects on free radicals and carbohydrate-metabolising enzymes

This research was performed to investigate in?vitro the biological activities of successive as well as 70% ethanol extracts of Nepeta cataria on some biochemical parameters including oxidative markers and carbohydrate-hydrolysing enzyme activities (α-amylase, β-galactosidase and α-glucosidase). Powdered N. cataria and its successive extracts were screened for their phytochemical constituents. Tests for tannins, carbohydrates, glycosides and flavonoids were positive in ethanolic extract, but those for steroids and terpenoids were positive in petroleum ether and chloroform extracts. Also, different extracts were chromatographically investigated. The results obtained demonstrated that different successive extracts of N. cataria exhibited an inhibitory effect on oxidative stress indices and carbohydrate-hydrolysing enzymes. It is observed that 70% ethanol, petroleum ether and chloroform extracts showed, respectively, the most potent inhibitory activities, while ethyl acetate and ethanol successive extracts appeared with moderate or low reducing activities.     

Phytochemical and in vitro screening of some Ficus and Morus spp. for hypolipidaemic and antioxidant activities and in vivo assessment of Ficus mysorensis (Roth)

Phytochemical screening of air-dried leaves and fruit juice of certain Ficus and Morus spp. have been studied. In an in?vitro study, the ethanol and hexane extracts of the investigated plants were evaluated against hyperlipidaemia by estimating the rate limiting enzyme of cholesterol biothenysis; β-hydroxy-β-methylglutaryl coenzyme A reductase (HMG-CoA reductase). The antioxidant activity was evaluated by reduction of DPPH(-) free radical. Extra phytochemical screening of Ficus extracts was undertaken, which recorded potent hypolipidaemic and antioxidant activities. The more pronounced extract, Ficus mysorensis (hexane extract), was evaluated in?vivo by estimation of the lipid profile and certain antioxidant parameters in hypercholesterolemic rats. The hexane fraction was chromatographed and six isolated compounds were identified. Furthermore, its saponifiable fraction was identified by a MS/MS technique. In conclusion, F. mysorensis recorded hypolipidaemic and antioxidant effects. Detailed studies of the isolated compounds must be undertaken for an evaluation against hypercholesterolemia and free radical elevation.     

A homotopy analysis solution to large deformation of beams under static arbitrary distributed load

In this article, homotopy analysis method (HAM) is employed to investigate non-linear large deformation of Euler–Bernoulli beams subjected to an arbitrary distributed load. Constitutive equations of the problem are obtained. It is assumed that the length of the beam remains constant after applying external loads. Different auxiliary parameters and functions of the HAM and the extra auxiliary parameter, which is applied to initial guess of the solution, are employed to procure better convergence rate of the solution. The results of the solution are obtained for two different examples including constant cross sectional beam subjected to constant distributed load and periodic distributed load. Special base functions, orthogonal polynomials e.g. Chebyshev expansion, are employed as a tool to improve the convergence of the solution. The general solution, presented in this paper, can be used to attain the solution of the beam under arbitrary distributed load and flexural stiffness. Ultimately, it is shown that small deformation theory overestimates different quantities such as bending moment, shear force, etc. for large deflection of the beams in comparison with large deformation theory. Finally, it is concluded that solution of small deformation theory is far from reality for large deflection of straight Euler–Bernoulli beams.     

Effect of Ni(II) substitution on phase stabilization electrical properties of BICo(III)VOX.20 oxide-ion conductor

The BICO_0.20–xNI_xVOX solid electrolyte was synthesized by the standard solid-state reaction. The effect of Ni(II) substitution for Co(III) on phase stabilization and oxide-ion performance has been investigated in the compositional range 0?≤?x?≤?0.20 using X-ray powder diffraction, differential thermal analysis and AC impedance spectroscopy. The highly conductive γ′-phase was effectively stabilized at room temperature for compositions with x?≥?0.13 whose thermal stability increases with Ni content. The complex plane plots of impedance were typically represented at temperatures below 380?°C, suggesting a major contribution of polycrystalline grains to the overall electrical conductivity. The dielectric permittivity measurements revealed the fact that suppression of the ferroelectric transition is compositionally dependent. Interestingly, the maximum ionic conductivity at lower temperatures (~2.56?×?10^?4?S^?cm^?1 at 300?°C) was observed for the composition with x?=?0.13. The variation of low-temperature conductivity with Ni content was accompanied with a general drop in the corresponding values of ΔE_LT. However, the local minimum high-temperature conductivity, σ₆₀₀?°C?~?2.26?×?10^?2?S^?cm^?1 for x?=?0.10, coupled with a local maximum value of ΔE_HT?~?0.48?eV was attributed to an increased defect trapping effect correlated with the V(V)?→?V(IV) reduction at elevated temperatures.     

Thermally Stimulated Depolarization Current and Thermal Analysis Studies of Gamma Irradiated Lithium‐Salt/Polymer Electrolyte Blends

Thermally stimulated depolarization current (TSDC) and thermal analysis studies of gamma irradiated LiOH/PVA blends were done. To study the mechanisms of conduction and TSDC in poly(vinyl alcohol) (PVA) and LiOH/PVA blends, short circuit TSDC at a polarizing temperature 353 K with a polarizing field of 3 kV cm^?1 have been analyzed in the temperature range 300–410 K. Two peaks are evident from the global TSDC measurements on the pure PVA homopolymer. Meanwhile, in all blended samples; there is only one broad peak with a shoulder on the high temperature side due to the relaxation of the poly‐blend system. The temperature dependence, 300–408 K, of the current density (J) for pure PVA and its blended samples has been studied. It was observed that J values increase dramatically with increasing temperature (in the low temperature region from 300–340 K) owing to the formation of local ordered regions in the otherwise disordered amorphous matrix of PVA. Further increase in the temperature caused a marginal increase in J values. The temperature dependence of the specific heat for all samples was measured. A linear increase of C _p was observed with an increase in temperature, which is ascribed to the increase in lattice vibration of linear macromolecules and consequently, increases in the number of internal degree of freedom of phonons.     

A general decay result for a memory-type thermoelasticity with second sound

In this paper, we consider an n-dimensional system of thermoelasticity with second sound in the presence of a viscoelastic term acting in the domain. We prove a general decay result from which the usual exponential and polynomial decay results are only special cases.     

Sensitization of Mn with CdS nanoparticles via electrochemical deposition technique for photocurrent enhancement of nanomaterial’s-sensitized photoelectrochemical cells

A photoconversion efficiency of 2.12% was obtained under visible light illumination by nanostructure-sensitized photoelectrochemical cells using Mn/CdS as sensitizer loaded on TiO₂ nanotube arrays (NTAs) (Mn/CdS/TiO₂). Sensitization of Mn on CdS nanoparticles pre-loaded on TiO₂ NTAs was carried out by a two-step electrodeposition method. Compared with unsensitized TiO₂ NTAs, the photocurrent had increased from 0.03 to 4.12 for Mn/CdS/TiO₂ prepared at 1 min. The effects of deposited Mn on the physical, chemical, and photoelectrochemical properties of the CdS/TiO₂ NTAs nanostructure were investigated by using UV–visible diffuse reflectance spectroscopy, X-ray diffractometry, and field-emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The photoelectrochemical analysis was examined in a three-electrode system under a halogen illumination by using the prepared film as the photo-anode.     

Syntheses, crystal structure and ab initio calculations of two new phosphoric triamides

The reaction of N-benzoylphosphoramidic dichloride with piperidine and 4-methylpiperidine lead to PhC(O)N(H)P(O)R₂ with R=piperidine (1) and R=4-methylpiperidine (2) as N-benzoyl-N′,N″-bis(piperidine) phosphoric triamide and N-benzoyl-N′,N″-bis(4-methylpiperidine) phosphoric triamide, respectively. The products have been characterized by ¹H, ¹³C, ³¹P NMR spectra, and by elemental analysis. The crystalline solid for (1) and (2) consists surprisingly of four and two independent molecules, respectively. There is a disorder in one amine group due to ring inversion in each conformer in compound 1. In the solid state, comparable magnitudes for the stabilization of the stable conformers for the more or less discrete molecules, the polarization effects, hydrogen bonding and the packing effects could be anticipated.

The geometry of compound (1) optimized by density functional calculations at the B3LYP/6-31++G* (d,p) level, is in good agreement with data obtained from X-ray crystallography.     

Joint Commission International accreditation: a laboratory perspective

Joint Commission International accreditation (JCIA) offers the international community a standards-based, objective process for evaluating healthcare organizations. The eleven JCIA standards are functionally organized. The standards are grouped by functions related to the provision of patient care and functions covering the provision of a safe, effective, and well-managed organization. The focus of the JCIA survey process is on the whole organization rather than on individual departments/services. The survey is carried out by trained and experienced healthcare peers. Healthcare organizations worldwide should be encouraged to seek accreditation such as that offered by JCIA. Where affordable, laboratories that are part of larger healthcare organizations should strive to achieve independent laboratory accreditation. The perspective of a laboratory undergoing a JCIA survey is briefly presented. Presented at the conference Quality in the Spotlight, March 2007, Antwerp, Belgium.