A new cathodoluminescence-microscope has been developed with a considerably improved detection limit. Time-dependent luminescence intensity changes observed during electron bombardment enabled the recognition of short-lived, long-lived, and brown luminescence colour types in ~-quartz.Short-rived bottle-green or blue luminescence colours with zones of non-luminescing bands are very common in authigenic quartz overgrowths, fracture fillings or idiomorphic vein crystals. Dark brown, short-lived yellow or pink colours are often found in quartz replacing sulphate minerals. Quartz from tectonically active regions commonly exhibits a brown luminescence colour. A red luminescence colour is typical for quartz crystallized close to a volcanic dyke or sill.The causes of these different and previously poorly understood luminescence colours were investigated using heat treatment, electron bombardment and electrodiffusion. Both natural and induced brown luminescence colours reflect the presence of lattice defects (nonbonding Si-O) due to twinning, mechanical deformation, particle bombardment or extremely rapid growth. The bottle-green and blue linearly polarized luminescence colour, characterized by a plane of polarization parallel to the c-axis, both depend on the presence of interstitial cations. The yellow and red luminescence colours in ~-quartz both exhibit a plane of polarization perpendicular to the c-axis and appear to be related to the presence of trace elements in an oxidizing solution and to ferric iron respectively.

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In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy.

Manufacturing of nanomaterials (NMs) is often complex and expensive, and their environmental risks are poorly understood or even unknown. An economization of testing NMs is therefore desirable, which can be achieved by miniaturizing test systems. However, the downsizing of test vessels and volumes can enlarge the surface/volume ratio (SVR) which in turn can affect the bioavailable concentration of adsorbing substances like NMs. The present study focused on the miniaturization of the acute toxicity test with Daphnia magna. The adaptations were verified with three reference substances, the non-adsorbing potassium dichromate (K2Cr2O7) and as potentially highly-adsorbing substances silver nanoparticles (AgNPs) and silver nitrate (AgNO3). The miniaturized test was conducted in 24-well microtiter plates (MT) and simultaneously compared to the OECD standard test (ST). Furthermore, the test duration was prolonged from 48 to 96 h since NMs tend to show effects only after extended exposure. The toxicity of K2Cr2O7 and AgNPs continued to increase within the prolonged test span. The test comparisons with K2Cr2O7 did not reveal any significant differences between ST and MT. AgNO3 toxicity was significantly decreased in MT compared to ST due to the enlarged SVR. The toxicity of AgNPs in MT after 24 h was equal to ST. Contrary to our expectations an exposure longer than 24 h resulted in an increase of AgNP toxicity in MT, possibly due to enhanced dissolution of silver. Microtiter plates are appropriate alternative test vessels for the Daphnia sp. acute toxicity test; thus, its miniaturization is feasible. The enlarged SVR has to be taken into account since it can affect the toxicity of potentially adsorbing substances. Furthermore, the standard test duration of 48 h might underestimate the toxicity of many substances, especially of NMs.

This work reports laboratory angle resolved XRF measurements with the goal of establishing laboratory techniques to obtain a more complete idea of the intralayer composition of multilayer samples.

The genetic diversity of natural populations and the increase in global temperature are becoming important issues in ecotoxicological research. We investigated the combined effects of 3 different temperature levels and 6 different levels of genetic diversity on the life history parameters of Chironomus riparius. Inbreeding and loss of genetic variation are major threats to small and endangered populations. The reduction of fitness due to inbreeding is more severe under stressful environmental conditions. We show that under even a moderate temperature stress, a decrease in genetic variation has important consequences on the fitness of populations. This indicates that the global temperature increase could have serious effects on the distribution and survival of locally distributed or rare species.KEY WORDS: Life-history parameters · Microsatellites · Diptera · Chironomidae · Genetic impoverishment Resale or republication not permitted without written consent of the publisherClim Res 33: [207][208][209][210][211][212][213][214] 2007 The aim of this study was to determine the interaction between temperature stress and inbreeding, using an ectothermic aquatic invertebrate to test if genetically impoverished populations exhibit a higher sensitivity to temperature shifts. We selected a species from the dipterian family of Chironomidae, the non-biting midge Chironomus riparius, representing a model organism with a benthic-associated life cycle. Chironomids are widely distributed in the temperate northern hemisphere and are characterised by a huge ecological tolerance (Armitage et al. 1995). They can be found in hot springs, eutrophic and oligotrophic ponds, lowland rivers, and sub-glacial streams (Pinder 1986). Chironomids have 3 aquatic juvenile (egg, larvae and pupae) and one aerial adult life-stages (Olivier 1971). Previous studies assessing the effect of temperature variation (12-37°C) on chironomid growth patterns concluded that growth was promoted by increasing temperature up to a certain limit (Sankarperumal & Pandian 1991, Stevens 1998, Frouz et al. 2002, Pery & Garric 2006. In contrast, female body size and fecundity decreased with higher temperatures (Frouz et al. 2002, Gong et al. 2002. These studies were all performed with single populations; the additional impact of genetic diversity in connection with the effects of temperature shifts was not investigated. Hence, we tested if the development and reproduction of Chironomus riparius are affected by temperature shifts (± 3°C) and if there is an interaction between these effects and genetic diversity. MATERIALS AND METHODS Test organismsFor the experiments, 6 different Chironomus riparius populations were used (Table 1). One population, with a high inbreeding level (Pop. VI) was obtained from ECT Ecotoxicology, Flörsheim. Five other genetically different populations (Pop. I-V) were derived from different generations of a multi-generation study (under controlled conditions) performed using our inbred inhouse mass culture (GEN-) and a genetically ...

Grazing incidence and grazing emission X-ray fluorescence spectroscopy (GI/GE-XRF) are techniques that enable nondestructive, quantitative analysis of elemental depth profiles with a resolution in the nanometer regime. A laboratory setup for soft X-ray GEXRF measurements is presented. Reasonable measurement times could be achieved by combining a highly brilliant laser produced plasma (LPP) source with a scanning-free GEXRF setup, providing a large solid angle of detection. The detector, a pnCCD, was operated in a single photon counting mode in order to utilize its energy dispersive properties. GEXRF profiles of the Ni-L line of a nickel-carbon multilayer sample, which displays a lateral (bi)layer thickness gradient, were recorded at several positions. Simulations of theoretical profiles predicted a prominent intensity minimum at grazing emission angles between 5° and 12°, depending strongly on the bilayer thickness of the sample. This information was used to retrieve the bilayer thickness gradient. The results are in good agreement with values obtained by X-ray reflectometry, conventional X-ray fluorescence and transmission electron microscopy measurements and serve as proof-of-principle for the realized GEXRF setup. The presented work demonstrates the potential of nanometer resolved elemental depth profiling in the soft X-ray range with a laboratory source, opening, for example, the possibility of in-line or even in situ process control in semiconductor industry.

Iron oxide nanoparticles (IONP) are currently being studied as green magnet resonance imaging (MRI) contrast agents. They are also used in huge quantities for environmental remediation and water treatment purposes, although very little is known on the consequences of such applications for organisms and ecosystems. In order to address these questions, we synthesised polyvinylpyrrolidone-coated IONP, characterised the particle dispersion in various media and investigated the consequences of an IONP exposure using an array of biochemical and biological assays. Several theoretical approaches complemented the measurements. In aqueous dispersion IONP had an average hydrodynamic diameter of 25 nm and were stable over six days in most test media, which could also be predicted by stability modelling. The particles were tested in concentrations of up to 100 mg Fe per L. The activity of the enzymes glutathione reductase and acetylcholine esterase was not affected, nor were proliferation, morphology or vitality of mammalian OLN-93 cells although exposure of the cells to 100 mg Fe per L increased the cellular iron content substantially. Only at this concentration, acute toxicity tests with the freshwater flea Daphnia magna revealed slightly, yet insignificantly increased mortality. Two fundamentally different bacterial assays, anaerobic activated sludge bacteria inhibition and a modified sediment contact test with Arthrobacter globiformis, both rendered results contrary to the other assays: at the lowest test concentration (1 mg Fe per L), IONP caused a pronounced inhibition whereas higher concentrations were not effective or even stimulating. Preliminary and prospective risk assessment was exemplified by comparing the application of IONP with gadolinium-based nanoparticles as MRI contrast agents. Predicted environmental concentrations were modelled in two different scenarios, showing that IONP could reduce the environmental exposure of toxic Gd-based particles by more than 50%. Application of the Swiss "Precautionary Matrix for Synthetic Nanomaterials" rendered a low precautionary need for using our IONP as MRI agents and a higher one when using them for remediation or water treatment. Since IONP and (considerably more reactive) zerovalent iron nanoparticles are being used in huge quantities for environmental remediation purposes, it has to be ascertained that these particles pose no risk to either human health or to the environment.