Determination of α-Cypermethrin from Soil by Using HPTLC

JPC – Journal of Planar Chromatography – Modern TLC - α-Cypermethrin is a synthetic pyrethroid insecticide used to control insects. In soil, α-cypermethrin biodegrades...     

The normalizer of

In this paper, the normalizers of , for k = 2 or 3, in the groups Γ^k of modular group Γ are given by using the concept of Γ^k axes of the set of left cosets of , on which Γ^k acts transitively, in Γ^k.     

Thioxanthone based water-soluble photoinitiators for acrylamide photopolymerization

The two water-soluble thioxanthone-based 2-(carboxymethoxy) thioxanthone, 1A and 2-thioxanthone-thioacetic acid sodium salts, 2A were synthesized and characterized by spectroscopic methods. The quantum yield for fluorescence emission (φ_f) in water was found to be 0.50 for 1A and 0.05 for 2A. The long phosphorescence lifetime, that is 201 and 114 ms in a matrix at 77 K for 1A and 2A, respectively, indicates a π-π∗ nature of the lowest triplet state. The triplet lifetimes were determined by laser flash photolysis as 12 and 12.6 μs for 1A and 2A. Polymerization of acrylamide (AAm) was initiated by both initiators in water. Decarboxylation of initiators was achieved during 20 min of irradiation. It was found that 2A initiated polymerization of AAm in water more efficiently than 1A.     

The complexation of rhodium(III) with acyclic diaminedithioether (DADTE) ligands

(103)Rhodium(III) complexes derived from seven acyclic tetradentate N(2)S(2) ligands (one diaminedithiol and six diaminedithioether ligands) have been synthesized and characterized. Structural variations in the ligand include the length of carbon backbone between the coordinating atoms (222; 232; 323; 333), the presence or absence of gem-dimethyl groups α to sulfur, and the nature of the organic moiety on the sulfurs (hydrogen, p-methoxybenzyl and methyl). For each ligand, the formation of cis and/or trans dichloro isomeric complexes was assessed. Two complexes have been further characterized by single crystal X-ray diffraction. Preparation of the (103)Rhodium(III) complexes was conducted and overall radiochemical yields, in vitro stability and log D(7.4) values were measured. From these studies, the ligand with the 232 chain length, gem-dimethyl groups and the methyl thioether (L4) emerged as a preferred ligand for formation of rhodium complexes with trans geometry and highest radiochemical yields.     

Spectrofluorimetric Determination of Aliskiren in Tablets and Spiked Human Plasma through Derivatization with Dansyl Chloride

A simple and sensitive method has been developed and validated for the determination of aliskiren (ALS) in its dosage forms and spiked plasma. The method was based on the reaction of the drug with dansyl chloride in the presence of bicarbonate solution of pH 10.5 to give a highly fluorescent derivative which was measured at 501 nm with excitition at 378 nm in dichloromethane. Different experimental parameters affecting the development of the method and stability were carefully studied and optimized. The calibration curves were linear over the concentration ranges of 100–700 and 50–150 ng/mL for standard solution and plasma, respectively. The limits of detection were 27.52 ng/mL in standard solution, 4.91 ng/mL in plasma. The developed method was successfully applied to the analysis the drug in the commercial tablets and spiked plasma samples. The mean recovery of ALS from tablets and plasma was 100.10 and 97.81%, respectively. A proposal of the reaction pathway was presented.     

Analysis of a two-party supply chain with random disruptions

We study a continuous-review inventory problem of a two-echelon supply chain with random disruptions, identify properties of the optimal cost function, compare the optimal order quantity with the classical economic order quantity, analyze the sensitivity of the optimal solution, and explore the conditions under which zero-inventory ordering policy is preferred.     

Constituents of Salvia microphylla

A new phenolic ester 2-( p-hydroxyphenyl)ethyl eicosaheptanoic acid ester (1) and a known one hexacosylferulate (2) were isolated from the acetone extract of Salvia microphylla. In addition, two sesquiterpenes beta-eudesmol (3) and 8alpha-hydroxy-beta-eudesmol (4), a diterpene carnosic acid 12-methyl ether (12-methoxycarnosic acid) (5), three triterpenes erithrodiol 3-acetate, oleanolic acid, lupeol and beta-sitosterol were obtained as known compounds from this plant extract. The structures of the isolated compounds were elucidated by spectroscopic methods, including one- and two- dimensional 1H- and 13C-NMR and MS spectroscopies. The selected compounds were tested for antimicrobial activity against standard bacterial strains, and only carnosic acid 12-methyl ether showed antimicrobial activity against S. aureus at 78 microg mL(-1).     

Crystallography and magnetism of two 1-(4-nitroxylphenyl)pyrroles

Stable radicals 1-(4-(N-tert-butyl-N-aminoxyl)phenyl)pyrrole (BNPP) and 1-(4-(N-[para-methoxyphenyl]-N-aminoxyl)phenyl)pyrrole (MNPP) were synthesized and characterized by crystallography and magnetism. BNPP crystals exhibit 1-D chains of intermolecular nitroxide NO to nitroxide CH3 contacts, but polycrystalline magnetic susceptibility measurements show quite small antiferromagnetic (AFM) exchange interactions. MNPP shows stronger AFM exchange interactions that appear to be associated with a 2-D planar mesh of crystallographic nitroxide to nitroxide (N)O...N(O) contacts of 4.0-4.2 A. The AFM behavior of MNPP can be fitted to a 2-D square planar Heisenberg antiferromagnetic exchange model with J/k = (-)0.78 +/- 0.04 K and mean field constant theta = (-)0.77 +/- 0.12 K.     

Antimicrobial Properties of Zeolite-X and Zeolite-A Ion-Exchanged with Silver,Copper, and Zinc Against a Broad Range of Microorganisms

Zeolites are nanoporous alumina silicates composed of silicon, aluminum, and oxygen in a framework with cations, water within pores. Their cation contents can be exchanged with monovalent or divalent ions. In the present study, the antimicrobial (antibacterial, anticandidal, and antifungal) properties of zeolite type X and A, with different Al/Si ratio, ion exchanged with Ag⁺, Zn²⁺, and Cu²⁺ ions were investigated individually. The study presents the synthesis and manufacture of four different zeolite types characterized by scanning electron microscopy and X-ray diffraction. The ion loading capacity of the zeolites was examined and compared with the antimicrobial characteristics against a broad range of microorganisms including bacteria, yeast, and mold. It was observed that Ag⁺ ion-loaded zeolites exhibited more antibacterial activity with respect to other metal ion-embedded zeolite samples. The results clearly support that various synthetic zeolites can be ion exchanged with Ag⁺, Zn²⁺, and Cu²⁺ ions to acquire antimicrobial properties or ion-releasing characteristics to provide prolonged or stronger activity. The current study suggested that zeolite formulations could be combined with various materials used in manufacturing medical devices, surfaces, textiles, or household items where antimicrobial properties are required.