Exact Solutions of Fisher and Generalized Fisher Equations with Variable Coefficients

In this work,we consider a Fisher and generalized Fisher equations with variable coefficients.Usingtruncated Painlevé expansions of these equations,we obtain exact solutions of these equations with a constrainton the coefficients a(t)and b(t).     

Carotenoid and Fatty Acid Compositions of an Indigenous Ettlia texensis Isolate (Chlorophyceae) Under Phototrophic and Mixotrophic Conditions

Ettlia oleoabundance (formerly known as Neochloris oleoabundance) is an attractive candidate for biodiesel production because of its high lipid accumulation, and it’s taking the majority of the attention among the strains of Ettlia genus; however, potential of the other genus members is unknown. An indigenous strain from Salda Lake (South West Turkey) identified by 18S rDNA sequencing as Ettlia texensis (GenBank accession no: JQ038221), and its fatty acid and carotenoid compositions under phototrophic and mixotrophic conditions was investigated to evaluate the potential of the strain for commercial uses. A threefold increase was observed in total lipid content (total fatty acids; from 13 % to 37 %) in mixotrophic culture respect to the phototrophic growth conditions. The oleic acid (C18:1) and alpha-linolenic acid (18:3) were the major unsaturated fatty acids accounting for 40 % and 13.2 % of total fatty acids in mixotrophic culture, respectively. Carotenoid analyses of the mixotrophic culture revealed the metabolite canthaxanthin, a commercially valuable carotenoid used mainly for food coloring, was the major constituent among other pigments. The possible use of E. texensis in biotechnological applications is discussed.     

Experimental and theoretical structural studies on 4-(2-phenylethyl)-5-(2-furyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione

The structural and conformational features of 4-(2-phenylethyl)-5-(2-furyl)-2, 4-dihydro-3H-1,2,4-triazole-3-thione (1a), which can be related to the biological activity, have been investigated by X-ray diffraction and molecular modeling techniques. Ab initio method (RHF/6-31G) and density functional theory (B3LYP/6-31G(D)) have been used to calculate structural parameters, conformations, and relative energy of two tautomeric specious (1a and 1b) of the title compound. The geometry and the conformation of the thione form, 1a, is well reproduced by the DFT (B3LYP/6-31G(D)) method as compared with X-ray structure in which this form is found. The thione form is also predicted to be 14.42 kcal/mol more stable than the thiol form in the gas-phase by the DFT method.     

Preparation and evaluation of topical microemulsion system containing metronidazole for remission in rosacea

The aim of this study was to prepare a topical water-in-oil type microemulsion containing metronidazole and to compare its effectiveness with a commercial gel product in the treatment of rosacea. A pseudo-ternary phase diagram (K(m)=2:1) was constructed using lecithin/butanol/isopropyl myristate/water. The microemulsion was chosen from the microemulsion region in the phase diagram. The formulation was a water-in-oil type microemulsion (droplet size: 11.6 nm, viscosity: 457.3 mPa·s, conductivity: 1.5 μs/cm, turbidity: 6.89 NTU) and the addition of the metronidazole did not alter the properties of the system. The release experiment showed that the release rate of metronidazole from the commercial gel product was higher than that of the microemulsion. Stability experiments showed that the metronidazole microemulsion remained stable for at least 6 months; none of the characteristic properties of the microemulsion had changed, the system retained its clarity and there was no sign that crystallization of metronidazole has occurred. Microemulsion was compared to a gel product in a randomized, double-blind, baseline-controlled, split-face clinical trial for the treatment of patients. After the 6-week treatment period there was a statistically significant difference in reduction of the main symptoms of rosacea. Of the patients treated with the microemulsion, 17% experienced complete relief from inflammatory lesions, and 50% from erythema. The microemulsion resulted in complete relief in 38% of the patients with telangiectasia while the commercial product did not provide any relief of telangiectasia symptoms. In conclusion, the microemulsion containing metronidazole was found to be more effective in reducing the symptoms of rosacea compared to the commercial gel product.     

Functionalization of Hydride‐Terminated Photoluminescent Silicon Nanocrystals with Organolithium Reagents

Hydride‐terminated photoluminescent silicon nanocrystals (SiNCs) were functionalized with organolithium compounds. The reaction is proposed to proceed through cleavage of Si?Si bonds and formation of a Si?Li surface species. The method yields colloidally stabilized SiNCs at room temperature with short reaction times. SiNCs with mixed surface functionalities can be prepared in an easy two‐step reaction by this method by quenching of the Si?Li group with electrophiles or by addressing free Si?H groups on the surface with a hydrosilylation reaction.     

Reinvestigation of the reaction of [Ru3(CO)12] with 2-mercaptobenzothiazole: X-ray structure of [(μ-H)2Ru3 (μ-η2-C7H4NS2)(μ3-η2-C7H4NS2)(CO)7]

Treatment of Ru₃(CO)₁₂ with 2-mercaptobenzothiazole at 68°C gave the known compound [(-H)Ru₃(₃-²-C₇H₄NS₂)(CO)₉] 1 and the new compound [(-H)₂Ru₃(-²-C ₇H₄NS₂) (₃-²-C₇H₄NS₂)(CO)₇] 2 in 15 and 10% yields respectively. Compound 2 has been characterized by elemental analysis, infrared, ¹H NMR and mass spectroscopic data together with single crystal X-ray crystallography. It crystallizes in the monoclinic space group C2/c with a = 31.662(6), b = 14.577(3), c = 11.602(2) Å, = 104.15(3)°, Z = 8, and V = 5192.4(2) ų. The compound consists of a Ru₃ triangle with three different Ru-Ru bond lengths [2.75264, 2.79084, 2.97604 Å] and the two 2-mercaptobenzothiazole ligands are differently attached to the metal atoms. Compound 2 is also obtained by the reaction of 1 with excess 2-mercaptobenzothiazole at 68°C.     

Spectroscopic,electrochemical, theoretical characterization and biological evaluation of a ferrocenyl-substituted unsymmetric azine ligand and its Cu(II) complex

Ferrocenyl-substituted unsymmetrical azine and its Cu(II) complex were prepared. The redox active ferrocene-based azine was obtained by condensation of 1-[(E)-hydrazono]-5-bromo-2-hydroxybenzene with ferrocene carboxaldehyde. The ferrocenyl ligand and its Cu(II) complex were characterized by IR, UV–vis, NMR, X-ray, magnetic susceptibility, molar electrical conductivity measurements, and TG techniques. The redox behaviors of the ferrocene compounds were investigated by cyclic voltammetry. Structural parameters and spectroscopic properties of the ligand and the Cu(II) complex were calculated by employing density functional theory (DFT) and time-dependent DFT and compared with available experimental data. We found slightly stronger binding ability for Cu(II) complex than the free ligand. DNA binding abilities for ferrocenyl-substituted unsymmetrical azine ligand and its Cu(II) complex are higher than some reported ferrocene compounds. We also studied DNA cleavage, superoxide and DPPH radical scavenging abilities of the compounds. Furthermore, the synthesized organometallic compounds can be bound to DNA through an intercalative mode.     

Barriers to internal rotation around the C-N bond in 3-(o-aryl)-5-methyl-rhodanines using NMR spectroscopy and computational studies. Electron density topological analysis of the transition states

We have investigated the pairs of rotational isomers for six 3-(o-aryl)-5-methyl-rhodanines (Z = H, F, Cl, Br, OH, and CH3) using NMR spectroscopy and density functional theory (DFT) calculations. Electron density topological and NBO analysis has demonstrated the importance of non-covalent interactions, characterised by (3, -1) bond critical points (BCPs), between the oxygen and sulfur atoms on the thiazolidine ring with the aryl substitutents in stabilizing the transition states. The energetic activation barriers to rotation have also been determined using computational results; rotational barriers for 3-(o-chlorophenyl)-5-methyl-rhodanine (3S) and 3-(o-tolyl)-5-methyl-rhodanine (6S) were determined experimentally based on NMR separation of the diastereoisomeric pairs, and the first-order rate constants used to derive the value of the rotational barrier from the Eyring equation.