Soil mobility of sewage sludge-derived dissolved organic matter, copper, nickel and zinc

A soil (sandy loam) column leaching study aimed to determine the extent of mobility and co-mobility of Cu, Ni, Zn and dissolved organic matter (DOM) released from a surface-application (equivalent to 50 t ds ha(-1)) of anaerobically-digested sewage sludge. Leaching of DOM through It the soil column was found to be almost un-retarded. Decidedly similar behaviour was exhibited by Ni suggesting that it migrated as organic complexes. Whilst Cu was also found to be leached, significant retardation was evident. However, the importance of DOM in promoting the mobility of both Cu and Ni was evidenced by their lack of mobility when added to the soil column as inorganic forms. The presence of DOM did not prevent Zn from becoming completely adsorbed by the soil solid phase. In relation to WHO drinking water guidelines, only Ni concentrations showed potential environmental significance. due to the relatively poor retention of Ni by the sludge solid phase. (C) 2003 Elsevier Ltd. All rights reserved.

Proliferative and anti-proliferative effects of titanium- and iron-based metallocene anti-cancer drugs

In previous work we have found that Cp2TiCl2 and its corresponding deriv. of tamoxifen, Titanocene tamoxifen, show an unexpected proliferative effect on hormone dependent breast cancer cells MCF-7. In order to check if this behavior is a general trend for titanocene derivs. we have tested two other titanocene derivs., Titanocene Y and Titanocene K, on this cell line. Interestingly, these two titanocene complexes behave in a totally different manner. Titanocene K is highly proliferative on MCF-7 cells even at low concns. (0.5 .mu.M), thus behave almost similarly to Cp2TiCl2. This proliferative effect is also obsd. in the presence of bovine serum albumin (BSA). In contrast, Titanocene Y alone has almost no effect on MCF-7 at a concn. of 10 .mu.M, but exhibits a significant dose dependent cytotoxic effect of up to 50% when incubated with BSA (20-50 .mu.g/mL). This confirms the crucial role played by the binding to serum proteins in the expression of the in vivo, cytotoxicity of the titanocene complexes. From the hydridolithiation reaction of 6-p-anisylfulvene with LiBEt3H followed by transmetallation with iron dichloride [bis-[(p-methoxy-benzyl)cyclopentadienyl]iron(II)] (Ferrocene Y) was synthesized. This complex, which was characterized by single crystal X-ray diffraction, contains the robust ferrocenyl unit instead of Ti assocd. with easily leaving groups such as chlorine and shows only a modest cytotoxicity against MCF-7 or MDA-MB-231 cells.

In situ calibration of atmospheric air conductivity instruments

A new method of measuring the total conductivity of atmospheric air is described. It depends on determination of the electrical relaxation time of a horizontal wire, mounted between two insulators, which is initially grounded and then allowed to charge freely. The total air conductivity derived is compared with that from an ion mobility spectrometer. Results from the two techniques agreed to within 1.2 fS m(-1). (c) 2006 American Institute of Physics.

Intercomparison of aircraft instruments on board the C-130 and Falcon-20 over southern Germany during EXPORT2000

In the summer 2000 EXPORT aircraft campaign (European eXport of Precursors and Ozone by long-Range Transport), two comprehensively instrumented research aircraft measuring a variety of chemical species flew wing tip to wing tip for a period of one and a quarter hours. During this interval a comparison was undertaken of the measurements of nitrogen oxide (NO), odd nitrogen species (NOy), carbon monoxide (CO) and ozone (O3). The comparison was performed at two different flight levels, which provided a 10-fold variation in the concentrations of both NO (10 to 1000 parts per trillion by volume (pptv)) and NOy (200 to over 2500 pptv). Large peaks of NO and NOy observed from the Falcon 20, which were at first thought to be from the exhaust of the C-130, were also detected on the 4 channel NOxy instrument aboard the C-130. These peaks were a good indication that both aircraft were in the same air mass and that the Falcon 20 was not in the exhaust plume of the C-130. Correlations and statistical analysis are presented between the instruments used on the two separate aircraft platforms. These were found to be in good agreement giving a high degree of correlation for the ambient air studied. Any deviations from the correlations are accounted for in the estimated inaccuracies of the instruments. These results help to establish that the instruments aboard the separate aircraft are reliably able to measure the corresponding chemical species in the range of conditions sampled and that data collected by both aircraft can be co-ordinated for purposes of interpretation.

Global estimates of snow water equivalent from passive microwave instruments: history, challenges and future developments

Snow properties have been retrieved from satellite data for many decades. While snow extent is generally felt to be obtained reliably from visible-band data, there is less confidence in the measurements of snow mass or water equivalent derived from passive microwave instruments. This paper briefly reviews historical passive microwave instruments and products, and compares the large-scale patterns from these sources to those of general circulation models and leading reanalysis products. Differences are seen to be large between the datasets, particularly over Siberia. A better understanding of the errors in both the model-based and measurement-based datasets is required to exploit both fully. Techniques to apply to the satellite measurements for improved large-scale snow data are suggested.

High resolution photoacoustic overtone spectroscopy of monofluoroacetylene, HCCF, with a titanium:sapphire ring laser

Intracavity photoacoustic overtone spectrum of monofluoroacetylene, HCCF, has been recorded in the wave number region 10 750–14 500 cm−1 with a titanium:sapphire ring laser. The spectrum contains many dense vibration–rotation band systems which can be resolved with Doppler limited resolution. Altogether 58 individual overtone bands have been analyzed rotationally. Many of the observed bands show perturbations of which some have been attributed to anharmonic resonance interactions. A Fermi resonance model based on conventional rectilinear normal coordinate theory has been used to assign vibrationally bands from this work and from earlier studies. Many of the observed vibrational term values and rotational constants can be reproduced well with this model. The results show the importance of the Fermi resonance interactions at the high overtone excitations.

A mathematical model of the in vitro keratinocyte response to chromium and nickel exposure

A mathematical model describing the main mechanistic processes involved in keratinocyte response to chromium and nickel has been developed and compared to experimental in vitro data. Accounting for the interactions between the metal ions and the keratinocytes, the law of mass action was used to generate ordinary differential equations which predict the time evolution and ion concentration dependency of keratinocyte viability, the amount of metal associated with the keratinocytes and the release of cytokines by the keratinocytes. Good agreement between model predictions and existing experimental data of these endpoints was observed, supporting the use of this model to explore physiochemical parameters that influence the toxicological response of keratinocytes to these two metals.

Low-temperature synthesis of ordered graphite nanofibres using nickel(II)-exchanged zeolites

Ordered graphite nanofibre formation has been observed at exceptionally low temperatures on admission of ethyne to zeolite Y, which had been exchanged with Ni(II). The samples have been characterised by TEM, carbon analysis, and electronic spectroscopy. Formation of the nanofibres requires no hydrogen, and was not observed when cation exchange was carried out at acidic pH. The observed fibres resemble herring-bone nanofibrils, growing from nickel particles, and ca. 90% have diameters in the range 35-40 nm. Similar fibres have also been grown using nickel-exchanged zeolite beta.

Nickel(II) complexes of terdentate or symmetrical tetradentate Schiff bases: Evidence of the influence of the counter anions in the hydrolysis of the imine bond in Schiff base complexes

Two sets of ligands, set-1 and set-2, have been prepared by mixing 1,3-diaminopentane and carbonyl compounds (2-acetylpyridine or pyridine-2-carboxaldehyde) in 1:1 and 1:2 ratios, respectively, and employed for the synthesis of complexes with Ni(II) perchlorate, Ni(II) thiocyanate and Ni(II) chloride. Ni(II) perchlorate yields the complexes having general formula [NiL2](ClO4)(2)(L = L-1 [N-3-(1-pyridin-2-yl-ethylidene)-pentane-1,3-diamine] for complex 1 or L-2[N-3-pyridin-2-ylmethylene-pentane-1,3-diamine] for complex 2) in which the Schiff bases are monocondensed terdentate, whereas Ni(II) thiocyanate results in the formation of tetradentate Schiff base complexes, [NiL(SCN)(2)] (L = L-3[N,N'-bis-(1-pyridin-2- yl-ethylidine)-pentane-1,3-diamine] for complex 3 or L-4 [N,N'-bis(pyridin-2-ylmethyline)-pentane-1,3- diamine] for complex 4) irrespective of the sets of ligands used. Complexes 5 {[NiL3(N-3)(2)]} and 6 {[NiL4(N-3)(2)]} are prepared by adding sodium azide to the methanol solution of complexes 1 and 2. Addition of Ni(II) chloride to the set-1 or set-2 ligands produces [Ni(pn)(2)]Cl-2, 7, as the major product, where pn = 1,3-diaminopentane. Formation of the complexes has been explained by the activation of the imine bond by the counter anion and thereby favouring the hydrolysis of the Schiff base. All the complexes have been characterized by elemental analyses and spectral data. Single crystal X-ray diffraction studies con. firm the structures of three representative members, 1, 4 and 7; all of them have distorted octahedral geometry around Ni(II). The bis-complex of terdentate ligands, 1, is the mer isomer, and complexes 4 and 7 possess trans geometry. (C) 2008 Elsevier B. V. All rights reserved.

The first metamagnetic thiocyanato-bridged one-dimensional nickel(II) complex

A novel single thiocyanato- bridged one- dimensional polymer, [NiL(NCS)(mu-NCS)](n) (L = N-1-(1-pyridin-2-yl-ethylidine)propane-1,3-diamine) has been synthesized and characterized by X-ray crystallography and a variable temperature magnetic study; the compound is a metamagnet with a Neel temperature (T-N) of 3.5 K.

Topotactic oxidation of TiGaPO-1, a pyridine-templated titanium gallophosphate with a new octahedral-tetrahedral 3-D framework structure containing Ti-III/Ti-IV

The first 3-D open-framework TiGaPO complex, constructed from (TiO6)-O-III, (TiO6)-O-IV, GaO4, and PO4 polyhedra, contains pyridinium cations in a 1-D pore network and can be oxidized in air at 543 K with retention of the original framework structure.

Potassium nickel(II) gallium phosphate hydrate, K[NiGa2(PO4)(3)(H2O)(2)]

The title compound, potassium nickel(II) digallium tris-( phosphate) dihydrate, K[NiGa2(PO4)(3)(H2O)(2)], was synthesized hydrothermally. The structure is constructed from distorted trans-NiO4(H2O)2 octahedra linked through vertices and edges to GaO5 trigonal bipyramids and PO4 tetrahedra, forming a three-dimensional framework of formula [NiGa2(PO4)(3)(H2O)(2)](-). The K, Ni and one P atom lie on special positions (Wyckoff position 4e, site symmetry 2). There are two sets of channels within the framework, one running parallel to the [10 (1) over bar] direction and the other parallel to [001]. These intersect, forming a three-dimensional pore network in which the water molecules coordinated to the Ni atoms and the K+ ions required to charge balance the framework reside. The K+ ions lie in a highly distorted environment surrounded by ten O atoms, six of which are closer than 3.1 angstrom. The coordinated water molecules are within hydrogen-bonding distance to O atoms of bridging Ga-O-P groups.

Nickel(II) complexes of tetradentate NSNO pyridylthioazophenol ligands: synthesis, characterization and crystal structure

Two sets of nickel(11) complexes of a series of tetradentate NSNO ligands were synthesized and isolated in their pure form. All these complexes, formulated as [Ni(L)Cl](2) and [Ni(L)(N-3)](2) [HL = pyridylthioazophenols], were characterized using physicochemical and spectroscopic tools. The solid-state structures of two complexes (1a and 2a) were established by X-ray crystallography. The geometry about the nickel ion of the complexes is octahedral and the complexes are dimeric in nature. In 1, two Ni(II) ions are bridged by two Cl- anions while in 2 they are bridged by two azide ions in a mu-1,1-bridging fashion. (C) 2008 Elsevier Ltd. All rights reserved.