A Learning Algorithm for Level Sets Weights in Weighted Level-based Averaging Method

The method which we call the Weighted Averaging Based on Levels (WABL) can be used to calculate the average representative of a fuzzy number. It utilizes weight coefficients for the level sets as well as the sides of a fuzzy number. We have developed an algorithm to obtain these coefficients. The most remarkable feature of this algorithm is that it makes use of the decision maker’s (DM) aggregation strategy.     

Utility of the Pfitzinger Reaction in the Synthesis of Novel Quinoline Derivatives and Related Heterocycles

2‐(2‐Amino‐3,5‐dinitrophenyl)‐2‐oxoacetic acid ( 2 ) was obtained from hydrolysis of 5,7‐dinitroisatin ( 1 ) in alkaline media. A novel quinoxaline derivative ( 3 ) was synthesized from the reaction of the same compound ( 1 ) with o‐phenylenediamine. Reacting 2 with ethyl 3‐oxo‐3‐phenylpropanoate yields 6,8‐dinitro‐2‐phenylquinoline‐3,4‐dicarboxylic acid ( 4 ). Then, 4 was converted into new quinoline‐diacylchloride, quinoline‐ester, quinoline‐dicarboxamide, pyridazine, and pyrroledione derivatives ( 5 , 6a , 6b , 6c , 6d , 7a , 7b , 7c , 7d , 8 , 9 , 10a , 10b , 10c , 10d , 11a , 11b , 12 ) with SOCl₂, alcohols, amines, and hydrazines, respectively. The structures of synthesized compounds were clarified by ¹H NMR, ¹³C NMR, IR, mass and elemental analysis methods.     

Catalytic Reaction Mechanism of Bacterial GH92 α-1,2-Mannosidase: A QM/MM Metadynamics Study

The catalytic mechanism of a -dependent family 92 -mannosidase, which is abundantly present in human gut flora and malfunctions leading to the lysosomal storage disease α-mannosidosis, has been investigated using quantum mechanics/molecular mechanics and metadynamics methods. Computational efforts show that the enzyme follows a conformational itinerary of and the ion serves a dual purpose, as it not only distorts the sugar ring but also plays a crucial role in orchestrating the arrangement of catalytic residues. This orchestration, in turn, contributes to the facilitation of conformers for the ensuing reaction. This mechanistic insight is well-aligned with the experimental predictions of the catalytic pathway, and the computed energies are of the same order of magnitude as the experimental estimations. Hence, our results extend the mechanistic understanding of glycosidases.     

Insights into Tris‐(2‐Hydroxylethyl)methylammonium Methylsulfate Aqueous Solutions

We report herein a combined experimental–computational study on tris‐(2‐hydroxylethyl)methylammonium methylsulfate in water solutions, as a representative ionic liquid of the aqueous‐solution behavior of hydroxylammonium‐based ionic liquids. Relevant thermophysical properties were measured as a function of mixture composition and temperature. Classical molecular dynamics simulations were performed to infer microscopic structural features. The reported results for ionic liquid in water‐rich solutions show that it behaves as isolated non‐interacting ions solvated by water molecules, through well‐defined solvation shells, exerting a disrupting effect on the water hydrogen bonding network. Nevertheless, as ionic liquid concentration increase, interionic association increases, even for diluted water solutions, evolving from the typical behavior of strong electrolytes in solution toward large interacting structures. For ionic‐liquid‐rich mixtures, water exerts a minor disrupting effect on the fluid’s structuring because it occupies regions around each ion (developing water–ion hydrogen bonds) but without significantly weakening anion–cation interactions.     

Selectivity in the aggregates of the chiral organolithium N-Boc-2-lithiopiperidine with a chiral ligand: a DFT study

In this paper the aggregates of the chiral organolithium N-Boc-2-lithiopiperidine [Boc=CO₂C(CH₃)₃], which play an important role in the formation of chiral 2-substituted piperidines found in many alkaloid structures and medicinal compounds, have been investigated within the framework of Density Functional Theory (DFT) calculations. In the complex structures, the lithium atoms are tetra-coordinated, the diaminoalkoxide ligand is tridentate to one lithium atom and forms a chelate with the substrate which is stabilized by the solvent diethyl ether. The same type of bonding was observed for all the different ligand-bound structures; for ligands 6 and 7, which have bulky substituents, selectivity was in agreement with experiment. The results shed light on the microscopic structures of these species and suggest a potential ligand, 11, to yield high enantioselectivity.     

Cytotoxicity of Silica Nanoparticles with Transcaucasian Nose-Horned Viper, <Emphasis Type="Italic">Vipera ammodytes transcaucasiana</Emphasis>, Venom on U87MG and SHSY5Y Neuronal Cancer Cells

Highly bioactive compounds of the snake venom make them particular sources for anticancer agent development. They contain very rich peptide-protein structures. Therefore, they are very susceptible to environmental conditions such as temperature, pH, and light. In this study, Vipera ammodytes transcaucasiana venom was encapsulated in PAMAM-G4 dendrimer by sol-gel method in order to prevent degradation of venom contents from the environmental conditions. For this purpose, nanoparticles were prepared by sol-gel methodology and SEM analyses were performed. U87MG and SHSY5Y neuronal cancer cell lines were treated with different concentrations of venom-containing nanoparticles and cytotoxicity was determined by MTT assay. IC₅₀ values of nanoparticles with snake venom were calculated as 37.24 and 44.64 μg/ml for U87MG and SHSY5Y cells, respectively. The IC₅₀ values of nanoparticles with snake venom were calculated as 10.07 and 7.9 μg/ml for U87MG and SHSY5Y cells, respectively. As a result, nanoparticles with V. a. transcaucasiana venom showed remarkably high cytotoxicity. Encapsulation efficiency of nanoparticles with 1 mg/ml snake venom was determined as %67 via BCA? protein analysis. In conclusion, this method is found to be convenient and useful for encapsulating snake venom as well as being suitable for drug delivery systems.     

Chemical composition and antimicrobial activity of the essential oil of <Emphasis Type="Italic">Anthemis wiedemanniana</Emphasis> from Turkey

The chemical composition and antimicrobial activity of the essential oil from aerial parts of Anthemis wiedemanniana, an endemic taxon of Turkey, were investigated. Linalool (12.75%), 1,8-cineole (8.49%), hexadecanoic acid (6.09%), and chrysanthenone (5.67%) were found to be the main components among the 122 compounds characterized in the essential oil of Anthemis wiedemanniana. Antimicrobial activities were reported against 12 microorganisms and five yeast-like fungi by the disc diffusion method. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 40–43, January–February, 2007.     

Photoacoustic method for the measurement of the thermal diffusivity of drawn foils

A nonstationary method to measure the thermal diffusivity of polymer foils with thicknesses between 10 and 40μm normal to the foil plane is described. The principle of the experimental technique is a modification of the photoacoustic effect. The quantity that is measured, is the phase angle between the modulation of the light intensity and the pressure variation as a function of frequency. A theoretical treatment of the phenomenon is presented which enables the evaluation of the diffusivity from the experimental data. It is possible to measure absolute values of the thermal diffusivity with an accuracy in the order of three percent and relative changes in the thermal diffusivity, e. g. by drawing, of one percent. Measurements were performed on commercial PETP foils of 19 and 30μm thickness drawn along various directions. For draw ratios up to 1.3 the diffusivity decreased about 20 percent or increased about 10 percent, depending on the foil thickness and the treatment during manufacture. The results can be interpreted with the aggregate model of Kilian and Pietralla as well as with the two-phase model of Choy and Young.     

Production of glycerides from glycerol and fatty acids by native lipase ofNigella sativa seed

The possible application of native lipase ofNigella sativa seed in the esterification of fatty acids to glycerol was investigated, and the effect of process parameters and the enzyme selectivity on the reaction were determined. For this aim, the esterification of oleic acid, sunflower oil fatty acids, and coco oil fatty acids with glycerol were studied.