Determination of some trace metals with a new synthesized polymer resin by FAAS in various tea and herbal plants samples

In this work, a new polymer resin with a functional groups capable of holding trace metals has been synthesized. The structure of polymer resin has been examined by BET-N₂ method analyzer, IR spectrometer, scanning electron microscope (SEM) and elemental microanalyser. The synthesized polymer resin was used for the simultaneous separation and preconcentration of the trace metals from various tea and herbal plants samples. After extraction process, flame atomic absorption spectrometry (FAAS) was used to determine the trace metals. The analytical parameters and solid phase extraction (SPE) performance such as pH, sample volume, flow rates of sample, flow rates of eluent, concentration, volume and type of eluent and effect of interference ions, were investigated. The limits of detection (DL) of the SPE procedure for trace metals, were calculated to be (3s) in the range of 0.9?4.0 μg L^?1 (n = 21) and the factors of preconcentration (PF) were obtained at 200 for Cd, Co, Cu, Fe, Ni and Zn, and at 50 for Cr, Mn and Pb ions and the relative standard deviation (RSD) at ≤ 2% (n = 11).     

Composition,properties, and application of products formed in oxidation of polyethylene by nitric acid

Structure of products formed in polyethylene oxidation by nitric acid was studied by NMR, IR, and electronic absorption spectroscopies and derivatography.     

Influence of using nanoobjects as filler on functionality-based energy use of nanocomposites

The goal of our study was to investigate the potential benefits of reinforcing polymer matrices with nanoobjects for structural applications by looking at both the mechanical properties and environmental impacts. For determining the mechanical properties, we applied the material indices defined by Ashby for stiffness and strength. For the calculation of environmental impacts, we applied the life cycle assessment methodology, focusing on non-renewable energy use (NREU). NREU has shown to be a good indicator also for other environmental impacts. We then divided the NREU by the appropriate Ashby index to obtain the ‘functionality-based NREU’. We studied 23 different nanocomposites, based on thermoplastic and thermosetting polymer matrices and organophilic montmorillonite, silica, carbon nanotubes (single-walled and multiwalled) and calcium carbonate as filler. For 17 of these, we saw a decrease of the functionality-based NREU with increasing filler content. We draw the conclusion that the use of nanoobjects as filler can have benefits from both an environmental point of view and with respect to mechanical properties.     

Topological properties of commodities networks

This paper investigates the topological properties of the commodities networks. We have found that commodities form strong clusters and are homogeneous with relation to sector (metals, agriculture and energy). We also develop a dynamic approach suggesting that agriculture commodities are very important in the network, followed by metals and energy. Furthermore, the parameters that characterize the network seem to be changing over time.     

Synthesis and complexation of a novel soluble vic-dioxime with hydroxyethyl pendant arms

A new soluble vic-dioxime ligand namely 1,4-bis(2′-hydroxyethyl)-2,3-bis(hydroxyimino)-5,6-diphenylpiperazine, (LH₂) containing optically active centers has been prepared as a mixture of isomers from (CNO)₂ and N,N-bis(2-hydroxyethyl)stilbendiamine (1) which has been made by the reduction of the condensation of the product of benzaldehyde and 2-aminoethanol in the presence of aluminum amalgam. N,N-coordinated planar metal complexes of this ligand have been synthesized with Ni^II, Cu^II, Co^II, Pd^II and U^VIO₂. Oxidation of (LH)₂Co in the presence of a base, such as pyridine, leads to an octahedral complex (LH)₂CopyCl containing pyridine and chloride as axial ligands in addition to vic-dioxime ligands. The structures of the ligand and its complexes are proposed on the basis of elemental analysis, ¹H-n.m.r., mass, i.r. and u.v.–vis. spectral data. This revised version was published online in June 2006 with corrections to the Cover Date.     

Determination of periodic solutions for nonlinear oscillators with fractional powers by He’s modified Lindstedt-Poincaré method

He’s modified Lindstedt-Poincaré method is applied to nonlinear oscillatiors with fractional powers. Comparison of the obtained results with exact solutions provides confirmation for the validity of He’s modified Lindstedt-Poincaré method.     

Optimization of the finned double-pipe heat exchanger using nanofluids as working fluids

Journal of Thermal Analysis and Calorimetry - The heat exchanger pipe diameter has a significant effect on the flow characteristics as well as on the initial investment, operation and overall cost....     

Novel tricarbonyl rhenium complexes of 5,8-quinolinedione derivatives - Synthesis, spectroscopic characterisation, X-ray structure and DFT calculations

The molecular structure of 7-acetamido-2-methyl-quinoline-5,8-dione has been determined and the reactivity of 7-acetamido-2-methyl-quinoline-5,8-dione (1) and 6-acetamido-2-methyl-quinoline-5,8-dione (2) towards Re(CO)₅Cl has been examined. Two novel tricarbonyl rhenium complexes, fac-[Re(CO)₃(7-acetamido-2-methyl-quinoline-5,8-dione)Cl]·CHCl₃ (3·CHCl₃) and fac-[Re(CO)₃(6-acetamido-2-methyl-quinoline-5,8-dione)Cl]₂·CHCl₃ (4·CHCl₃), have been synthesized and characterized spectroscopically and structurally. The electronic spectrum of 3 was investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ.     

Phenolic compounds from the aerial parts of Clematis viticella L. and their in vitro anti-inflammatory activities*

Phytochemical investigations on the EtOH extract of Clematis viticella led to the isolation of six flavonoid glycosides, isoorientin (1), isoorientin 3′-O-methyl ether (2), quercetin 7-O-α-L-rhamnopyranoside (3), quercetin 3,7-di-O-α-L-rhamnopyranoside (4), manghaslin (5) and chrysoeriol 7-O-β-D-glucopyranoside (6), one phenylethanol derivative, hydroxytyrosol (7), along with three phenolic acids, caffeic acid (8), (E)-p-coumaric acid (9) and p-hydroxybenzoic acid (10). The structures of the isolates were elucidated on the basis of NMR and HR-MS data. All compounds were isolated from C. viticella for the first time. Compounds 7 and 8 showed significant anti-inflammatory activity at 100 μM by reducing the release of NO in LPS-stimulated macrophages comparable to positive control indomethacin. Compounds 3 and 7 exhibited anti-inflammatory activity through lowering the levels of TNF-α while 1, 3 and 5 decreased the levels of neopterin better than the positive controls.     

Simultaneous Determination of Chromium Species in Water and Plant Samples at Trace Levels by Ion Chromatography–Inductively Coupled Plasma-Mass Spectrometry

Ion chromatography–inductively coupled plasma-mass spectrometry (IC–ICP-MS) was used for the identification and quantification of chromium species. Chromium(III) and chromium(VI) were separated and determined by IC–ICP-MS. The separation was achieved using an anion exchange column with 0.55?M HNO₃ as mobile phase. It was a particular goal of this work to exclusively use nitric acid for elution in order to reduce interferences in the ICP-MS system. Analytical figures of merit were calculated under the optimum conditions by developing calibration plots in a concentration range of 0.50–250?µg/L for both species. The detection limits for Cr(III) and Cr(VI) were 0.09 and 0.03?µg/L, respectively. Spiked recovery tests were used to evaluate the applicability of the analytical method in environmental samples, and the recoveries ranged between 97 and 103% for both analytes. The accuracy of the method for total chromium content was validated through the analysis of a spring water-certified reference material (UME 1201), and the obtained results were in good agreement with the certified value. Lettuce seedlings were cultivated to evaluate the intake levels of these species. In addition, the bioaccessibility of Cr(III) and Cr(VI) from the lettuce seedlings in simulated gastric and intestinal fluids media was examined.