Ecological risk assessment of sediment in wastewater discharging area by means of metal speciation

This study was designed to evaluate the influence of wastewater discharge to the marine ecosystem after treatment plant construction. Heavy metal concentrations in sediment and bioavailability of the metals were analyzed and ecological risks were assessed using the results. Metal speciation for sediments collected in the wastewater discharging area was measured by a Shimadzu AA-680 atomic absorption spectrometer. The distribution of the metals among various geochemical phases was determined. Biological samples collected and analyzed were four species of crustacea, four species of bivalve, and seven species of fish. Exchangeable fraction of superficial sediment (0–2 cm layer) was Zn 35.09%, Ph 5.30%, Cu 0.86%, Cr 0.01% and Fe 0%. However, exchangeable fraction of deep layer sediment (15–20 cm) was not detected for all metals analyzed. Deeper sediments were found to have more residual fraction, and bioavailable phases decreased by depth, which provides an indication of the seriousness of wastewater discharge effect in this enclosed bay. The chemical concentrations observed to be associated with biological effects were sorted. The comparisons were made with regard to the potential for adverse biological effects. The potential of adverse biological effects in the sediments of wastewater discharge site was estimated as Zn 69.8%, Pb 35.8%, Cu 29.1%, and Cr 21.1%, respectively. Mullet (Mugil cephalus) among biological samples had the highest concentration of Zn in the muscle and liver organs. The bioconcentration factors (BCFs) of Zn by the mullet, mussel, oyster and crab were the highest among heavy metals determined. This result was well related to 81.6% of bioavailable phase Zn and 69.8% of adverse biological effects for the surface sediment.     

Development and validation of a liquid chromatography method with electrospray ionization tandem mass spectrometry for the determination of brotizolam residues in beef and commercial whole milk

In this work, a liquid chromatography–tandem mass spectrometric detection technique was developed and validated for the determination of brotizolam residues in beef muscle and commercial whole milk. This procedure involves the extraction of the analyte from the samples via liquid–solid extraction, and caffeine was used as an internal standard. The analyte was successfully separated on an XTerra‐C₁₈ column, with a mobile phase composed of 0.01% formic acid in acetonitrile and 1 mm ammonium formate–0.01% formic acid in water. The one‐step extraction method evidenced good selectivity, precision (RSD = 9.87–26.47%), and the recovery of the extractable analyte was 92.61–115.98% in the matrices. The limits of quantification ranged between 0.4 and 0.5 µg/kg. The developed method is simple since it requires no additional cleanup procedures. Copyright © 2011 John Wiley & Sons, Ltd.     

Moving interfacial crack between piezoelectric ceramic and elastic layers

An analysis is performed for the problem of a finite Griffith crack moving with constant velocity along the interface of a two-layered strip composed of a piezoelectric ceramic and an elastic layers. The combined out-of-plane mechanical and in-plane electrical loads are applied to the strip. Fourier transforms are used to reduce the problem to a pair of dual integral equations, which is then expressed in terms of a Fredholm integral equation of the second kind. The dynamic stress intensity factor(DSIF) is determined, and numerical results show that DSIF depends on the crack length, the ratio of stiffness and thickness, and the magnitude and direction of electrical loads as well as the crack speed. In case that the crack moves along the interface of piezoelectric and elastic half planes, DSIF is independent of the crack speed.     

Tris(1,10-phenanthroline)copper(II) di-μ-iodo-bis­(diiodo­mercurate) dimethyl sulfoxide monohydrate

In the cationic complex present in the title compound, [Cu(C₁₂H₈N₂)₃][Hg₂I₆]·C₂H₆OS·H₂O, the copper(II) center adopts a highly distorted octa­hedral geometry, ligated by the six N atoms of three 1,10-phenanthroline ligands. The structure includes an iodide-bridged dimeric mercurate anion for neutrality and uncoordinated dimethyl sulfoxide and water mol­ecules.     

Orthogonal Polynomial Solutions of Spectral Type Differential Equations: Magnus' Conjecture

Let τ=σ+ν be a point mass perturbation of a classical moment functional σ by a distribution ν with finite support. We find necessary conditions for the polynomials {Q_n(x)}^∞_n=0, orthogonal relative to τ, to be a Bochner–Krall orthogonal polynomial system (BKOPS); that is, {Q_n(x)}^∞_n=0 are eigenfunctions of a finite order linear differential operator of spectral type with polynomial coefficients: L_N[y](x)=∑^N_i=1 ℓ_i(x) y⁽ⁱ⁾(x)=λ_ny(x). In particular, when ν is of order 0 as a distribution, we find necessary and sufficient conditions for {Q_n(x)}^∞_n=0 to be a BKOPS, which strongly support and clarify Magnus' conjecture which states that any BKOPS must be orthogonal relative to a classical moment functional plus one or two point masses at the end point(s) of the interval of orthogonality. This result explains not only why the Bessel-type orthogonal polynomials (found by Hendriksen) cannot be a BKOPS but also explains the phenomena for infinite-order differential equations (found by J. Koekoek and R. Koekoek), which have the generalized Jacobi polynomials and the generalized Laguerre polynomials as eigenfunctions.     

Electrical Conductivity and Physical Properties of Poly(Dipropargylsilane Derivatives) Doped with Electron Acceptors

Abstract

Films of poly(dipropargylsilane derivatives) were easily prepared by solvent casting. The resulting red-black films were relatively flexible and ductile. By doping with electron acceptors, the electrical conductivity increased up to the order of 10^?1-10⁰ S/cm. The activation energy for the conduction of doped film was 4 kcal/mol. The change in Raman, IR, and UV-visible spectra by doping suggests electron transfer from the poly(dipropargylsilane derivatives) to the dopant, leading to the formation of polaron. It also was observed that doping with I₂ drastically destroys the crystallinity of the polymer.     

Formation of TiO2 nanoparticles in water-in-CO2 microemulsions

Titanium dioxide nanoparticles can be produced by the controlled hydrolysis of titanium tetraisopropoxide in water-in-CO2 (w/c) microemulsions stabilized with the surfactants ammonium carboxylate perfluoropolyether (PFPE-NH4) and poly(dimethyl amino ethyl methacrylate-block-1H,1H,2H,2H-perfluorooctyl methacrylate) (PDMAEMA-b-PFOMA); the greater control of hydrolysis and particle growth with PDMAEMA-b-PFOMA is consistent with the differences in the stabilities and interactions for these two microemulsions.     

Sodium hydrogen nitrilo­tri­acetate dihydrate

In the title compound, Na⁺·C₆H₈NO₆^?·2H₂O, the sodium ion is coordinated in a distorted octahedral manner by two carboxyl­ate O atoms and two water O atoms. Each of these water mol­ecules bridges two adjacent Na ions, resulting in two four‐membered rings of the type Na–O–Na–O.     

[5,10,15,20‐Tetrakis­(penta­fluoro­phenyl)­porphyrinato]­iron(II) benzene disolvate

The title compound, [Fe(C₄₄H₈F₂₀N₄)]·2C₆H₆, contains a four‐coordinated Fe^II atom, which lies on a center of symmetry. The porphyrin macrocycle is planar, and the Fe—N bond distances are in the range 1.9891 (13)–1.9982 (13) Å. The spin state of the Fe^II atom is intermediate (S = 1), as confirmed by NMR spectroscopy. The asymmetric unit contains two half benzene mol­ecules, each lying about an independent inversion centre; one of the benzene rings is located just below (and by inversion symmetry, another is just above) the Fe atom, where it interacts weakly with the porphyrin ring.