Literatura científica selecionada sobre o tema "DR CALUX®"

Capacitor oil samples (PCBs > 90%wt) were treated in a bench scale experiment to investigate the destruction of PCBs during chemical destruction processes (a catalytic hydrodechlorination treatment with palladium carbon and additional treatment with potassium tert-butyloxide). Using those results, this study confirmed the decrease of PCBs and other undesirable dioxin-like compounds such as PCDD/Fs in treated samples during the treatment. Dioxin-responsive chemical-activated luciferase expression (DR CALUX®) AhR reporter gene bioassay was used to evaluate dioxin-like activity in the samples. During the treatment, the efficiency for PCB capacitor oil was around 99.99% or more in WHO-TEQ and CALUX-TEQ, whereas the sum of PCBs was reduced at a resulting efficiency of >99.9999%. In this study, a new cleanup procedure for separating PCBs from the mineral oil matrix was also developed for DR CALUX. The procedure consists of dimethylsulphoxide partitioning followed by silica gel-44% sulphuric acid reflux treatment and activated carbon chromatography. With the cleanup, CALUX-TEQ values were in good agreement with WHO-TEQ values and were as much as 3.3 times higher than WHO-TEQs for untreated/treated PCB-containing insulating oil samples. The DR CALUX results of mineral oil samples containing various PCB concentrations of 0.5–50 mg/kg (corresponding WHO-TEQs: 0.012–1.2 μg-TEQ/g) also correlated well with WHO-TEQs (CALUX-TEQ/WHO-TEQ ratio =1.0–3.0), which was consistent with the theoretical quantification limit of the CALUX. These results supported the validity of the proposed clean-up method.

ABSTRACT Fish consumption is the principal source of intake of organochlorinated compounds in humans. Compared with other types of foods of animal origin, fish contain the highest levels of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans, all of which are classified as highly toxic organochlorine compounds. Currently, lakes and fish farms in northern Italy are not regularly monitored for PCBs and dioxins in areas contaminated by industrial sources, partially because of the high costs of traditional analytical methods that limit the number of samples to be analyzed. The DR-CALUX cell bioassay is based on the uptake of the cellular aryl hydrocarbon receptor (AhR) for dioxins and dioxin-like compounds. The aim of this study was to assess the levels of dioxins and dioxin-like PCB contamination in Lake Maggiore and Lake Como, two lakes in northwestern Italy, and in nearby areas. The levels were quantified using the cell bioassay DR-CALUX and reference controls in two wild fish species, perch (Perca fluviatilis) and roach (Rutilus rutilus), and in a farmed species, rainbow trout (Oncorhynchus mykiss). Tissue samples collected from the farmed rainbow trout were also submitted to immunohistochemical analysis of CYP1A expression as a marker for environmental pollutant-induced liver damage. The levels of dioxins, furans, and dioxin-like PCBs were all below the maximum levels and action limits set by European Union Regulation, suggesting no risk for human health associated with the consumption of the fish species caught or farmed in these areas.

Abstract Schipper, C. A., Lahr, J., van den Brink, P. J., George, S. G., Hansen, P-D., da Silva de Assis, H. C., van der Oost, R., Thain, J. E., Livingstone, D., Mitchelmore, C., van Schooten, F-J., Ariese, F., Murk, A. J., Grinwis, G. C. M., Klamer, H., Kater, B. J., Postma, J. F., van der Werf, B., and Vethaak, A. D. 2009. A retrospective analysis to explore the applicability of fish biomarkers and sediment bioassays along contaminated salinity transects. – ICES Journal of Marine Science, 66: 2089–2105. Biological-effects monitoring in estuarine environments is complex as a result of strong gradients and fluctuations in salinity and other environmental conditions, which may influence contaminant bioavailability and the physiology and metabolism of the organisms. To select the most robust and reliable biological-effect methods for monitoring and assessment programmes, a large-scale field study was conducted in two estuarine transects in the Netherlands. The locations ranged from heavily polluted harbour areas (the ports of Rotterdam and Amsterdam) to cleaner coastal and freshwater sites. Assessment methods used included a variety of biomarkers in flounder (Platichthys flesus) and a range of in vitro (sediment extracts) and in vivo bioassays. Multivariate statistical analysis was applied to investigate correlations and relationships between various biological effects and contaminant levels in flounder liver or sediments. Several biological methods seemed to be too much affected by salinity differences for routine use in estuaries. The most discriminative biomarkers in the study were hepatic metallothionein content and biliary 1-OH pyrene in fish. Mechanism-based in vitro assays DR-CALUX and ER-CALUX applied to sediment extracts for screening of potential toxicity were much more responsive than in vivo bioassays with macro-invertebrates using survival as an endpoint.

A topsoil sample obtained from a highly industrialized area (Taranto, Italy) was tested on the DR-CALUX® cell line and the exposed cells processed with proteomic and bioinformatics analyses. The presence of polyhalogenated compounds in the topsoil extracts was confirmed by GC-MS/MS analysis. Proteomic analysis of the cells exposed to the topsoil extracts identified 43 differential proteins. Enrichment analysis highlighted biological processes, such as the cellular response to a chemical stimulus, stress, and inorganic substances; regulation of translation; regulation of apoptotic process; and the response to organonitrogen compounds in light of particular drugs and compounds, extrapolated by bioinformatics all linked to the identified protein modifications. Our results confirm and reflect the complex epidemiological situation occurring among Taranto inhabitants and underline the need to further investigate the presence and sources of inferred chemicals in soils. The combination of bioassays and proteomics reveals a more complex scenario of chemicals able to affect cellular pathways and leading to toxicities rather than those identified by only bioassays and related chemical analysis. This combined approach turns out to be a promising tool for soil risk assessment and deserves further investigation and developments for soil monitoring and risk assessment.

Environmental pollution is one of the most serious problems facing humanity and other life forms on our planet today. The characterization of chemicals spread in the environment, through the standard procedure of Environmental Risks Assessment (ERA) still evaluates the risk substance-by-substance. However, it is known that in the environment we are exposed to a mixture of chemicals coming from several different sources. In order to overcome such limitations of current ERA approach, more recently ERA highly recommended the usage of bioanalytical tools which is still emerging and not established in each European Member State. Within this thesis the suitability of bioanalytical tools in the ERA of industrial and agricultural areas, where mixtures of contaminants are present, has been demonstrated. In particular, the suitability of the in vitro cellular bioassay DR CALUX® (Dioxin Responsive, Chemically Activated LUciferase gene eXpression) has been evaluated. DR CALUX® were able to detect the biological toxicity of topsoils collected from Taranto municipality (Apulia Region). Through a combined approach of bioassay and chemical analysis, the occurrence and spatial distribution of polyhalogenated dioxins, furans and dl-PCBs in topsoil samples were assessed. This approach not only confirmed already known sources (e.g. industrial air emissions) but also new ones (e.g. illegal disposal of electric transformers containing Apirolio® and asbestos cement-fiber plates). Considering the extension of illegal landfills in the Taranto municipality area, it is an urgent need to investigate potential sources and impact of dioxin-like compounds. Here we evaluated the suitability of DR CALUX® to support their application in future monitoring surveys. The risk represented by the extensive use of soils for agricultural and food purposes in Taranto area, further underlines the need to apply monitoring tools that quickly and extensively highlight the hazard posed by dioxin-like compounds in terms of human and environmental health. The high costs associated to extensive monitoring surveys find in the application of bioassays a successful alternative, able to identify new and unexpected sources and their route of exposure that would require long times and huge investments if only based on analytical chemical analysis. The possibility to couple proteomics to the DR CALUX® cells bioassay was also investigated in the present thesis. A case study was thus designed and tested by using selected topsoil samples to extrapolate differentially abundant proteins by proteomics and thus monitor other chemicals including those of emerging concerns (CECs) present in the soil sample able to activate specific cellular pathways. Moreover, differently abundant proteins spots found will subjected to functional and pathway analysis, in order to highlight potentially altered molecular pathways and suggesting potential link to human pathologies. The differential proteins identified were related to an altered unfolded protein response (UPR) inducing Endoplasmic Reticulum (ER) stress, oxidative stress, and altered signal transduction, transforming growth factor beta (TGF-β) signaling alteration. All these mechanisms are reported to be related to carcinogenic mechanisms. The combined approach leads to estimate ecological and human risk by legacy and CECs as pharmaceuticals. The suitability of combining bioanalytical tools with chemical analyses in order to evaluate potential risks for both humans and environment, was demonstrated also in sewage sludge (SL) and hydrochar (HC) samples. A case study was designed to test urban SL and relative HC from six wastewater treatment plants (WWTPs), located in the Tuscany territory. DR CALUX® bioassay was able to detect the presence of dioxins and dioxin-like compounds in both SL and HC underlying differences probably related to hydrothermal carbonization process (HTC). Chemical analysis show that highly chlorinated congeners prevailed in SL compared to HC samples, in agreement with previous studies. HTC process seems responsible for such changes in the level of chlorinated congeners from high to low ones, which are more toxic. It can be assumed that the contamination of the HC is mainly due to a previous contamination of SL feedstock. The increase in the biological toxicity observed by DR CALUX® can be related to the de-chlorination of dioxins and dioxin-like compounds and the high loss of water which might affect their levels. DR CALUX® bioassay was able to screen the presence of dioxins and dioxin-like compounds in SL and HC, raising concern due to their possible applications as soil amendments. In the light of the above findings, it is possible to state that the DR CALUX® bioassay has been proven to be an effective and sensitive tool able to screen the presence of dioxins and dioxin-like compounds in various environmental matrices such as topsoil, sludge and hydrochar. Moreover, it has been proven to be an integrated state-of-the-art tool capable of assessing the real toxicity of complex mixtures of contaminants that occur in environmental samples. The combined application of DR CALUX® bioassay with chemical analysis and proteomics, opens new paths to the future of the Environmental Risk Assessment.

Prémisses: Les Autochtones sont exposés à plusieurs contaminants par leur alimentation traditionnelle. Les niveaux plasmatiques élevés de certains contaminants mesurés chez les Inuits et Cris nous ont menés à l'hypothèse voulant qu'ils soient impliqués dans une diminution de la qualité osseuse chez ces populations. Objectif: Investiguer la relation entre les paramètres osseux ultrasonores (QUS) mesurés au niveau du calcanéum de femmes inuites et cries et leurs concentrations plasmatiques de composés Dioxin-Like (DLC) mesurées à l'aide d'un bioessai. La relation entre les paramètres QUS et les concentrations plasmatiques de certains biphényles polychlorés-dioxin-like mono-ortho-substitués (BPC-ZXL-105, -118, -156, -157, -167, -189) a également été étudiée. Méthodes: Cent quarante neuf Inuites de Nuuk (Groenland), 195 Inuites du Nunavik et 249 Cries du Nord-du-Québec, âgées de 35 à 74 ans, ont été incluses dans cette étude. Les paramètres osseux (vitesse du son, atténuation des ondes, indice de rigidité) ont été mesurés par ultrasonographic (Appareil Achilles Lunar au Groenland et Achilles InSight® au Nunavik et chez les Cries). Les DLC ont été mesurés par le bio-essai Dioxin-Responsive Chemically-Activated LUciferase expression (DR-CALUX) et les BPC-DL, par chromatographie en phase gazeuse avec détecteur à capture d'électrons dans le Projet Groenland et par la chromatographic gazeuse couplée à la spectrométrie de masse, dans les Projets Nunavik et Cri. Les relations contaminant-paramètre osseux ont été investiguées en régression linéaire simple et multiple. Résultats: Aucune relation n'a été observée entre le niveau des DLC mesuré par DR-CALUX et les valeurs des paramètres osseux. Par contre, des relations significatives négatives ont été identifiées entre les niveaux plasmatiques des BPC-.DZ (BPC-DL-105, -118 et -157) et les paramètres ultrasonores qui reflètent la qualité osseuse. La relation observée était dans certains cas (BPC-DZ-105, -118, -156, -167 et -189) modérée par le poids corporel, la parité, le niveau sanguin de mercure et la présence d'une cause secondaire d'ostéoporose. Conclusion: Outre les BPC mono-ortho substitués, l'étude a permis d'identifier plusieurs autres facteurs qui pourraient affecter la qualité osseuse, dont certains étaient investigués pour la première fois (acides gras polyinsaturés Oméga-3 et Oméga-6, vitamine A, mercure, sélénium, plomb, molybdène, cobalt, zinc, nickel, cuivre, fer, iode, arsenic, et creatinine).

This book is a unique blend of history, technology review, theoretical fundamentals, and design guide. The subject matter is primarily piston aeroengine superchargers – developed in Germany during the Second World War (WWII) – which are centrifugal compressors driven either by the main engine crankshaft or by an exhaust gas turbine. The core of the book is an unpublished manuscript by Karl Kollmann, who was a prominent engineer at Daimler-Benz before and during the war. Dr. Kollmann’s manuscript was discovered by Calum Douglas during his extensive research for his earlier book on piston aeroengine development in WWII. It contains a wealth of information on aerothermodynamic and mechanical design of centrifugal compressors in the form of formulae, charts, pictures, and rules of thumb, which, even 75 years later, constitute a valuable resource for engineering professionals and students. In addition to the translation of the original manuscript from German, the authors have completely overhauled the chapters on the aerothermodynamics of centrifugal compressors so that the idiosyncratic coverage (characteristic of German scientific literature at that time) is familiar to a modern reader. Furthermore, the authors added chapters on exhaust gas turbines (for turbo-superchargers), piston aeroengines utilizing them, and turbojet gas turbines. Drawing upon previously unpublished material from the archived German documents, those chapters provide a concise but technically precise and informative look into those technologies, where great strides were made in Germany during the war. In summary, the coverage is intended to be useful not only to history buffs with a technical bent but also to the practicing engineers and engineering students to help with their day-to-day activities in this particular field of turbomachinery.