Nickel-induced blood biochemistry alterations in hens after an experimental peroral administration

The purpose of this study was to determine certain blood biochemical parameters in hens of Isa Brown breed (n = 20) after nickel administration. Animals were divided into four groups (K, P1, P2, P3). Experimental hens (n = 5; in each group) received nickel (NiCl2) as peroral administration in drinking water in various doses (P1 - 0.02 g NiCl2/L; P2 - 0.2 g NiCl2/L; P3 - 2.0 g NiCl2/L of drinking water) for 28 days. The last group - K (n = 5) was the control, receiving no nickel. Biochemical parameters of mineral profile (calcium; phosphorus; magnesium; sodium; potassium) and of energy and enzymatic profile [(glucose; total cholesterol; total proteins; triglycerides; alanine aminotransferase (ALT) aspartate aminotransferase (AST) gamma glutamyl transferase (GGT) and glutamatdehydrogenase (GLDH)] were analyzed in blood serum on Day 0, 7, 14, 21 and 28 of the experiment. Average levels of mineral metabolism parameters were relatively stable apart from calcium. The evaluation registered a significant decrease in calcium during the experiment mainly in the group with highest nickel concentration in drinking water. No significant differences were detected between groups in energy and enzymatic profile apart from the concentrations of ALT on Day 7. In conclusion, there were significant associations between nickel levels and calcium and ALT in blood serum of the hens. No significant differences were detected in other biochemical parameters of mineral profile (P, Mg, Na, K) and energy and enzymatic profile (glucose, total cholesterol, total proteins, triglycerides, AST, GGT and GLDH) after nickel administration. Our results may contribute to an evaluation of reference levels of analyzed parameters, to monitor the health and nutritional status of hens. In this study also the negative effect of nickel mainly on calcium metabolism was detected.     

Interlaboratory trial to determine the analytical state-of-the-art of bromate determination in drinking water

The new European Directive for water intended for human consumption has established a regulatory level for bromate at 10 microg L(-1). This Maximum Admissible Concentration requires analytical methods with detection limits of a least 2.5 microg L(-1). A project funded by the Standards, Measurements and Testing Programme of the European Commission has enabled the improvement and/or development of methods for the determination of bromate at such concentration levels. This collaborative work was concluded by the organisation of an interlaboratory trial involving 26 European laboratories, which enabled the testing of both a draft ISO Standard method and alternative methods. This paper presents the results of this interlaboratory trial, along with results of a bromate stability study. The progress made with respect to the analytical state-of-the-art for bromate will greatly benefit the quality of measurements carried out in water quality monitoring.     

Biogeochemical patterns in a river network along a land use gradient

The Bode catchment (Germany) shows strong land use gradients from forested parts of the National Park (23 % of total land cover) to agricultural (70 %) and urbanised areas (7 %). It is part of the Terrestrial Environmental Observatories of the German Helmholtz association. We performed a biogeochemical analysis of the entire river network. Surface water was sampled at 21 headwaters and at ten downstream sites, before (in early spring) and during the growing season (in late summer). Many parameters showed lower concentrations in headwaters than in downstream reaches, among them nutrients (ammonium, nitrate and phosphorus), dissolved copper and seston dry mass. Nitrate and phosphorus concentrations were positively related to the proportion of agricultural area within the catchment. Punctual anthropogenic loads affected some parameters such as chloride and arsenic. Chlorophyll a concentration and total phosphorus in surface waters were positively related. The concentration of dissolved organic carbon (DOC) was higher in summer than in spring, whereas the molecular size of DOC was lower in summer. The specific UV absorption at 254 nm, indicating the content of humic substances, was higher in headwaters than in downstream reaches and was positively related to the proportion of forest within the catchment. CO₂ oversaturation of the water was higher downstream compared with headwaters and was higher in summer than in spring. It was correlated negatively with oxygen saturation and positively with DOC concentration but negatively with DOC quality (molecular size and humic content). A principle component analysis clearly separated the effects of site (44 %) and season (15 %), demonstrating the strong effect of land use on biogeochemical parameters.     

Selection of ecological indicators for the conservation, management and monitoring of Mediterranean coastal salinas

Salinas systems are artificial wetlands which are interesting from the viewpoint of nature conservation. They play an important role both as habitats for migratory waterbird species and as nodes of biotic connectivity networks. In the Mediterranean basin, where the coastal salinas are highly significant as alternative and complementary habitats for waterbirds, a process of abandonment occurs, and many seminatural systems of this kind are disappearing. This abandonment is having serious consequences for migratory bird populations and for the ecological role these play. In the present paper, this group of waterbird species has been used to evaluate these wetlands for conservation purposes. We have developed a methodological approach for the selection of ecological indicators for the conservation and management of these Mediterranean habitats and waterbird assemblages, the main consumers therein. The stepwise procedure developed constitutes a practical tool for this task. Application thereof enabled us to differentiate the habitats available for the waterbirds and to identify the biotic and abiotic indicators for the maintenance and management of the salina ecosystems. These variables can then be incorporated into monitoring programs.     

Use of headspace SPME-GC-MS for the analysis of the volatiles produced by indoor molds grown on different substrates

An automated headspace solid phase microextraction method followed by GC-MS analysis was used to evaluate and compare the in vitro production of microbial volatile organic compounds (MVOCs) on malt extract agar, plasterboard and wallpaper. Five fungal strains were isolated from the walls of water-damaged houses and identified. In addition, four other common molds were studied. In general, MVOC production was the highest on malt extract agar. On this synthetic medium, molds typically produced 2-methylpropanol, 2-methylbutanol and 3-methylbutanol. On wallpaper, mainly 2-ethylhexanol, methyl 2-ethylhexanoate and compounds of the C8-complex such as 1-octene-3-ol, 3-octanone, 3-octanol and 1,3-octadiene were detected. The detection of 2-ethylhexanol and methyl 2-ethylhexanoate indicates an enhanced degradation of the substrate by most fungi. For growth on plasterboard, no typical metabolites were detected. Despite these metabolite differences on malt extract agar, wallpaper and plasterboard, some molds also produced specific compounds independently of the used substrate, such as trichodiene from Fusarium sporotrichioides and aristolochene from Penicillium roqueforti. Therefore, these metabolites can be used as markers for the identification and maybe also mycotoxin production of these molds. All five investigated Penicillium spp. in this study were able to produce two specific diterpenes, which were not produced by the other species studied. These two compounds, which remain unidentified until now, therefore seem specific for Penicillium spp. and are potentially interesting for the monitoring of this fungal genus. Further experiments will be performed with other Penicillium spp. to study the possibility that these two compounds are specific for this group of molds.     

Spindle dynamics identification using particle swarm optimization

Optimal parameters to eliminate machining chatter may be identified using analytical stability models which require the dynamics of the tool-holder-spindle-machine assembly. Receptance coupling substructure analysis (RCSA) provides a useful analytical tool to couple measured spindle-machine dynamics with tool-holder models to predict the tool point frequency response function for the assembly. Previous research has demonstrated a procedure to determine all required spindle receptances from a single measurement, where each mode within the measurement bandwidth was modeled as a fixed-free Euler–Bernoulli beam and fit using a manual, iterative procedure. Here, a particle swarm optimization technique is described for fitting the spindle-machine measurement using a fixed-free Euler–Bernoulli beam model for each mode. The performance of the optimization process and RCSA in predicting the tool tip frequency response is evaluated and the results are presented.