New pyrazolic compounds as cytotoxic agents

The evaluation of the in vitro cytotoxic properties of two pyrazole compounds: 1-(4-nitrophényl)-3,5-diméthylpyrazole (1) and 1,1'-di(4-nitrophényl)-5,5'-diisopropyl-3,3'-bipyrazole (2) was investigated against Hep cell line (Human laryngeal carcinoma). These two compounds showed an important cytotoxic activity on the Hep cell line, with IC(50): 8.25 microg mL(-1) for the compound 1; IC(50): 10.20 microg mL(-1) for the compound 2 while the IC(50) for adriamycine used as positive control was 3.62 microg mL(-1).     

Electrochemical degradation of buprofezin insecticide in aqueous solutions by anodic oxidation at boron-doped diamond electrode

Buprofezin (2-tert-butylimino-3-isopropyl-5-phenyl-1,3,5-thiadiazinan-4-one) is identified as a commonly used chemical with satisfactory biological activities against sucking insect pests, but its disposal causes serious environmental problems. This pesticide was treated by an electrolysis system using a boron-doped diamond (BDD) as anode and platinum as cathode. A number of experiments were run on a laboratory scale and the results are presented. The chemical oxygen demand (COD) measurement during the processing permitted the evaluation of the kinetic of organic matter decay and the instantaneous current efficiency. Different operating conditions and factors affecting the treatment process including current density, conductive electrolyte, pH, concentration of buprofezin, and time of electrolysis were studied and optimized. The best obtained conditions for COD removal on the BDD anode to degrade buprofezin solutions (COD₀ = 1,200 mg L^?1) include operating at 60 mA cm^?2 and 25 ± 3 °C. The high efficiency of this technology can be explained in terms of the direct electrooxidation at the BDD surface and the oxidation carried out by hydroxyl radicals (OH^?) and other electro-generated oxidants (Cl^?, ClO^?).     

Posner’s second theorem for Jordan ideals in rings with involution

Posner’s second theorem states that the existence of a nonzero centralizing derivation on a prime ring forces the ring to be commutative. In this paper we extend this result to Jordan ideals of rings with involution. Moreover, some related results are also discussed.     

The Fredholm alternative for parabolic evolution equations with inhomogeneous boundary conditions

We study the Fredholm properties of parabolic evolution equations on R with inhomogeneous boundary values. These problems are transformed into evolution equations with inhomogeneities taking values in certain extrapolation spaces. Assuming that the underlying homogeneous problem is asymptotically hyperbolic, we show the Fredholm alternative for these equations. The results are applied to parabolic partial differential equations.     

Robustness of Fredholm properties of parabolic evolution equations under boundary perturbations

We study perturbations at the boundary of linear nonautonomousparabolic boundary value problems. Our approach relies on atransformation of the given inhomogeneous boundary value problemto an evolution equation in larger, time-varying extrapolationspaces. We establish the well-posedness of this equation andDuhamel's formulas relating the evolution families solving theperturbed and the unperturbed problem. By means of these formulas,we can show that the perturbed evolution equation inherits theexponential dichotomy and Fredholm properties of the unperturbedequation if the perturbations are small in norm or compact.This result leads to a Fredholm alternative for the given perturbedboundary value problem.     

Magnetic properties of a new cobalt hydrogen vanadate with a dumortierite‐like structure: Co13.5(OH)6(H0.5VO3.5)2(VO4)6

The magnetic properties of a novel cobalt‐based hydrogen vanadate, Co_13.5(OH)₆(H_0.5VO_3.5)₂(VO₄)₆, are reported. This new magnetic material was synthesized in single‐crystal form using a conventional hydrothermal method. Its crystal structure was determined from single‐crystal X‐ray diffraction data and was also characterized by scanning electron microscopy. Its crystal framework has a dumortierite‐like structure consisting of large hexagonal and trigonal channels; the large hexagonal channels contain one‐dimensional chains of face‐sharing CoO₆ octahedra linked to the framework by rings of VO₄ tetrahedra, while the trigonal channels are occupied by chains of disordered V₂O₄ pyramidal groups. The magnetic properties of this material were investigated by DC magnetic measurements, which indicate the occurrence of antiferromagnetic interactions.     

Adsorption and corrosion inhibition of mild steel in hydrochloric acid solution by verbena essential oil

The inhibitive action of verbena essential oil (VEO) on the corrosion of mild Steel in 1 M HCl solutions in the temperature range 298 to 328 K was measured by use of the weight-loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy. Results showed that VEO inhibited corrosion of C38 steel in 1 M HCl solution and that inhibition efficiency increased with increasing concentration of inhibitor but decreased proportionally with temperature. Potentiodynamic polarization studies suggested VEO is a mixed-type inhibitor, with the anodic type predominating. Nyquist plots were depressed semicircles with their centre below the real axis. Adsorption of VEO by the C38 steel surface followed the Langmuir adsorption isotherm. Kinetic data for dissolution were investigated.