Two-dimensional q-differential transformation and its application

The one-dimensional q-differential transformation was introduced in [8] for solving the ordinary q-differential equations. Here, we present the definition and operation of the two-dimensional q-differential transform. A distinctive feature of the q-differential transform is its ability to solve linear and nonlinear partial q-differential equations.     

Novel Cr (III), Fe (III) and Ru (III) Vanillin Based Metallo‐Pharmaceuticals for Cancer and Inflammation Treatment: Experimental and Theoretical Studies

In this study, three novel complexes comprising trivalent Cr (III), Fe (III) and Ru (III) with imine ligand derived from 2‐amino‐3‐hydroxypyridine and o‐vanillin (H₂L) have been synthesized and characterized via wide range of spectroscopic and analytical tools such as ¹H NMR and ¹³C NMR, infrared (IR) and UV–Vis spectrophotometry, conductivity and magnetic measurements. The obtained results along with DFT data confirmed a 1:1 (metal: ligand) stoichiometry with non‐planner geometries for the three complexes. The binding action and the docking study of the prepared metal‐complexes to calf thymus DNA was also studied by absorption spectra and viscosity technique, which revealed that the three complexes interact strongly with DNA through intercalative binding mode. Significantly, these metal‐imine complexes showed strong and efficient anti‐inflammatory and antimicrobial activities against various gram‐positive (Microccus luteus), gram‐negative (Escherichia coli and Serratia marcescence) bacteria, and three strains of fungus. Moreover, all complexes exhibited more potent cytotoxicity effect on the outgrowth of different types of carcinoma cells, including human colon (HCT‐116 cell line), breast (MCF‐7 cell line), and hepatic cellular (HepG‐2), than the clinically‐proven Vinblastine standard.     

Sequential Chemistry Toward Core–Shell Structured Metal Sulfides as Stable and Highly Efficient Visible-Light Photocatalysts

A universal sequential synthesis strategy in aqueous solution is presented for highly uniform core–shell structured photocatalysts, which consist of a metal sulfide light absorber core and a metal sulfide co-catalyst shell. We show that the sequential chemistry can drive the formation of unique core–shell structures controlled by the constant of solubility product of metal sulfides. A variety of metal sulfide core–shell structures have been demonstrated, including CdS@CoS_x, CdS@MnS_x, CdS@NiS_x, CdS@ZnS_x, CuS@CdS, and more complexed CdS@ZnS_x@CoS_x. The obtained strawberry-like CdS@CoS_x core–shell structures exhibit a high photocatalytic H₂ production activity of 3.92 mmol h⁻¹ and an impressive apparent quantum efficiency of 67.3 % at 420 nm, which is much better than that of pure CdS nanoballs (0.28 mmol h⁻¹), CdS/CoS_x composites (0.57 mmol h⁻¹), and 5 %wt Pt-loaded CdS photocatalysts (1.84 mmol h⁻¹).     

Synthesis,characterization and anticancer studies of ferrocenyl complexes containing thiazole moiety

A ferrocenyl ligand was prepared from condensation of l,l′‐diacetylferrocene with 2‐amino‐5‐methylthiazole, to give the ligand. This ligand forms 1:1 complexes with lead(II), cobalt(II), nickel(II), copper(II) and zinc(II) in good yield. Characterization of the ligand and complexes was carried out using IR, NMR, electronic absorption, magnetic susceptibility, molar conductivity and elemental analysis. Anticancer activity of the prepared ligand and its complexes against breast cancer cell line MCF‐7 was determined. The anticancer activity of the new complexes was accompanied by significant increase in the activity of superoxide dismutase, with a parallel decrease in the activities of catalase and glutathione peroxidase and reduced glutathione level. Accordingly, the overproduction of free radicals allowed reactive oxygen species‐mediated cancer cell death. The results suggest that the complexes possess significant anticancer activity comparable to cisplatin. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis and crystal structure determination of two dispiro compounds from laboratory x‐ray powder diffraction data

The crystal structures of the dispiro compounds 1,3,4,8,10,11‐Hexaphenyl‐13‐methyl‐1,2,8,9,13‐pentaazadispiro[4.1.4.3]tetradeca‐2,9‐dien‐6‐one ( 3a ) and 4,11‐Bis(4‐methoxyphenyl)‐13‐methyl‐1,3,8,10‐tetraphenyl‐1,2,8,9,13‐pentaazadispiro‐[4.1.4.3]tetradeca‐2,9‐dien‐6‐one ( 3b ) have been determined at room temperature from X‐ray powder diffraction data using the method of simulated annealing as implemented in the programs DASH and TOPAS. Subsequent Rietveld refinements using the data collected to 1.5 Å resolution yielded R‐Bragg values of 2.2% for ( 3a ) and 3.7% for ( 3b ). It was found, that both compounds crystallize in the monoclinc space group P 2₁/n with lattice parameters of a = 17.1656(5) Å, b =13.8128(3) Å, c = 16.1016(5) Å, and β = 103.7330(2)° for ( 3a ) and a = 17.2529(8) Å, b = 13.8729(5) Å, c =16.1287(10) Å, and β = 103.6910(3)° for ( 3b ). Both compounds exhibit a distorted hexagonal close type of packing (hcp) of the molecular centers of gravity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectrophotometric methods for sertraline hydrochloride and/or clidinium bromide determination in bulk and pharmaceutical preparations

A spectrophotometric procedure for the determination of sertraline hydrochloride (Sert) and/or clidinium bromide (Clid) in bulk sample and in dosage forms was developed. The purpose of this work was to develop a rapid, simple, inexpensive, precise, and accurate visible spectrophotometric method. The procedure is based on formation of an ion-pair complex by their reaction with bromocresol green (BCG), bromophenol blue (BPB), and bromothymol blue (BTB) in buffered aqueous solution at pH 3. The colored products are extracted into a polar solvent and measured spectrophotometrically at the optimum λ_max for each complex. Optimization of different experimental conditions is described. Regression analysis of Beer-Lambert plots showed good correlation in the concentration range of 1–30 μg mL⁻¹. The apparent molar absorptivity, Sandell sensitivity, detection and quantification limits were calculated. For more accurate analysis, Ringbom optimum concentration range of 2–27 μg mL⁻¹ was used. The developed methods were successfully applied for the determination of sertraline hydrochloride and clidinium bromide in bulk in pharmaceutical formulations without any interference from common excipients. The procedure has the advantage of being highly sensitive and simple for the determination of the studied drugs, weak UV-absorbing compounds.     

Logarithmic stability estimates for an inverse source problem from interior measurements

This paper deals with an inverse monopolar source problem for the Poisson equation, from interior measurements, whose motivation lies in the sea water intrusion phenomenon. Global logarithmic stability estimates of locations and intensities for monopolar sources in this equation are established. To do that, we make an appropriate choice of a test function allowing to show a stability estimate with respect to boundary conditions and then we use an observability inequality for Laplace equation to control it by the interior measurements. This reveals, on the one hand, the distance between the source and on the other hand the gap between the associated measures.     

Chemical Constitution and Antimicrobial Activity of Kombucha Fermented Beverage

Kombucha is a traditional beverage of sweetened black tea fermented with a symbiotic association of acetic acid bacteria and yeasts. In this study, kombucha fermented beverage (KFB) appeared to include nine chemical groups (alcohols, acids, lactones, condensed heterocyclic compounds, antibiotics, esters, aldehydes, fatty acids, and alkaloids) of many bioactive metabolites, as elucidated by gas chromatography–mass spectrometry (GC-MS) and IR spectra. The fermented metabolic components of KFB seem collectively to act in a synergistic action giving rise to the antimicrobial activity. Four types of kombucha preparations (fermented, neutralized, heat-treated and unfermented) were demonstrated with respect to their antimicrobial activity against some pathogenic bacterial and fungal strains using agar well diffusion assay. KFB exerted the strongest antimicrobial activities when compared with neutralized and heat-treated kombucha beverages (NKB and HKB). Staphylococcus aureus ATCC6538 (S. aureus) and Escherichia coli ATCC11229 (E. coli) were the organisms most susceptible to the antimicrobial activity of kombucha beverage preparations. Finally, the KFB preparation showed remarkable inhibitory activity against S. aureus and E. coli bacteria in a brain heart infusion broth and in some Egyptian fruit juices (apple, guava, strawberry, and tomato). These data reveal that kombucha is not only a prophylactic agent, but also appears to be promising as a safe alternative biopreservative, offering protection against pathogenic bacteria and fungi.     

Spectrophotometric determination of some amino heterocyclic donors through charge transfer complex formation with chloranilic acid in acetonitrile

The present study is directed toward a development of simple, rapid and accurate spectrophotometric method for determination of some amino heterocyclic donors. The Charge transfer (CT) interactions between 3-aminopyrazole (AP), 3,5-dimethyl-pyrazole (DMP), 3-amino-5-methyl-pyrazole (AMP), 2-amino-4-methyl-thiazole (AMT), 2-amino-5-methyl-1,3,4-thiadiazole (AMTD) and 2-amino-5,6-dimethyl-1,2,4-triazine (ADMT) with chloranilic acid (CLA) as π-acceptor have been investigated spectrophotometrically in acetonitrile. Factors controlling the CT-reactions were also studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients were identified with high accuracy and precision. Job's method of continuous variation, spectrophotometric and conductometric titrations were used to identify the composition of the formed CT-complexes. Benesi-Hildebrand (BH) equation has been used to calculate the formation constants of the charge transfer reactions K_CT and the molar extinction coefficients ε. Free energy change (ΔG^o), oscillator strength (f), transition dipole moment (µ), ionization potential (I_P) and charge transfer energy of the formed CT-complexes (E_CT) were also determined and evaluated.     

Aqueous polymerization of methyl methacrylate catalyzed by corundum and characterization of the obtained polymers

The aqueous polymerization of methyl methacrylate (MMA) was studied using sodium bi-sulfite as initiator in the absence and presence of corundum (Al₂O₃). It was found that corundum has a catalytic effect on the polymerization reaction. The polymers obtained in the presence of corundum were found to have a wider molecular weight distribution than in its absence; this was deduced by thin-layer chromatographic analysis in a binary mixture (benzene: methanol 1:1.5 by volume) at 25°C. The apparent energy of activation was calculated between 40 and 50°C, and was found to be 4.50 × 10⁴ and 1.70 × 10⁴ J/mol in the absence and presence of 0.5 g corundum (type 600 grit)/105 mL of the reaction mixture, respectively.