Riverine fish in densely populated areas is constantly exposed to wastewater-borne contaminants from effluent discharges. These can enter the organism through the skin, gills or by ingestion. Whereas ...most studies assessing the contaminant burden in exposed fish have focused either on muscle or a limited set of tissues. Here we set out to generate a more comprehensive overview of the distribution of pollutants across tissues by analyzing a panel of matrices including liver, kidney, skin, brain, muscle, heart, plasma and bile. To achieve a broad analyte coverage with a minimal bias towards a specific contaminant class, sample extracts from four fish species were analyzed by High-Performance Liquid Chromatography (HPLC) - high-resolution mass spectrometry (HRMS) for the presence of 600 wastewater-borne pharmaceutically active compounds (PhACs) with known environmental relevance in river water through a suspect-screening analysis. A total of 30 compounds were detected by suspect screening in at least one of the analyzed tissues with a clear prevalence of antidepressants. Of these, 15 were detected at confidence level 2.a (Schymanski scale), and 15 were detected at confidence level 1 following confirmation with authentic standards, which furthermore enabled their quantification. The detected PhACs confirmed with level 1 of confidence included acridone, acetaminophen, caffeine, clarithromycin, codeine, diazepam, diltiazem, fluoxetine, ketoprofen, loratadine, metoprolol, sertraline, sotalol, trimethoprim, and venlafaxine. Among these substances, sertraline stood out as it displayed the highest detection frequency. The values of tissue partition coefficients for sertraline in the liver, kidney, brain and muscle were correlated with its physicochemical properties. Based on inter-matrix comparison of detection frequencies, liver, kidney, skin and heart should be included in the biomonitoring studies of PhACs in riverine fish.
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•Six fish tissues and 2 body fluids were analyzed for 600 pharmaceuticals.•Sertraline is present as bound form in non-target fish tissues.•Low concentrations of pollutants were detected in muscle.•Kidney, liver, skin and heart are proposed for detection of PhACs in fish.
•A miniaturized method was validated for the analysis of 47 drugs in fish muscle.•Developed method: a fast ultrasound (USE) extraction and Z-Sep/C18 sorbent clean-up.•HPLC–QToF-MS data adquisition ...with recording SWATH mode.•Most frequently detected drugs: caffeine, carbamazepine, diltiazem and verapamil.•Suspect screening retrieved benzoylecgonine, cocaine, nicotine, and ofloxacin.
A fast method for analysis of 47 pharmaceuticals active compounds (PhACs) in fish muscle has been developed and validated addressing the parameters accuracy, precision (intraday and interday), matrix effect at three spiking levels: 5, 25 and 50 ng PhAC g−1 in fish as well as linearity, limit of detection (LOD), limit of quantification (LOQ). Sixteen protocols were performed varying extraction techniques, solvents, sample filtration and clean-up step. The selected method was based on an ultrasound extraction with acidified mixture of acetonitrile and isopropyl alcohol followed by a clean-up step using Z-Sep/C18 sorbents. Quantitative analysis of the PhACs in the extracts was accomplished by UPLC- QTOF-MS using Sequential Window Acquisition of All Theoretical Fragment-Ion, SWATHTM acquisition technology. 90% Of the compounds presented extraction recoveries between 60 and 130% with LOQ between 0.2 and 11 ng g−1. The validated method was applied to the analysis of 32 muscle samples from thirteen different species of fish collected in four European river basins (Adige, Evrotas, Llobregat and Sava). A total of ten compounds were found in fish samples with diltiazem as the most frequently detected one followed by carbamazepine and caffeine. Additionally, by taking advantage of the information-rich mass spectral data from the SWATH mode acquisition, the raw data were reprocessed for the presence of the most prescribed 250 pharmaceuticals, metabolites, and drugs of abuse previously reported to occur in the aquatic environment. By considering the mass errors of the molecular ion (˂± 3 ppm) and one characteristic fragment ion (˂±10 ppm) as well as the Library score and the Formula Finder score of the data processing software six compounds were retrieved, and eventually four of them confirmed with authentic standards: cocaine and its metabolite benzoylecgonine, the stimulant nicotine, and the antibiotic ofloxacin. Two lipid regulators, lovastatin and simvastatin, were determined as a false positive.
Color difference thresholds in dental ceramics Ghinea, Razvan; Pérez, María M; Herrera, Luis J ...
Journal of dentistry,
2010, 2010-00-00, 2010-1-00, 20100101, Volume:
38
Journal Article
Peer reviewed
Abstract Objectives The objective of the study was to determine the perceptibility and acceptability thresholds for dental ceramics using CIEDE2000 (Δ E00 ) and CIELAB ( Δ E ab ) color difference ...formulas and a novel TSK Fuzzy Approximation. Methods A 13-observer panel performed independent observations of perceptibility and acceptability judgments on 105 pairs of ceramic discs (14 mm in diameter and 3 mm thick). Color differences of the disc pairs were calculated using both color difference formulas (Δ E00 ranged from 0.10 to 9.91). Two fitting procedures were used: S-shaped curve and TSK Fuzzy Approximation. For both procedures, from the resultant fitting curves, the 95% confidence intervals were estimated and the 50:50% thresholds were calculated (50% positive and 50% negative answers). Results With the S-shaped fitting procedure, a 50:50% acceptability threshold was found to be Δ E00 = 2.25 ( r2 = 0.88) and Δ E ab = 3.46 ( r2 = 0.85). Corresponding values with a TSK Fuzzy Approximation were Δ E00 = 2.23 ( r2 = 0.89) and Δ E ab = 3.48 ( r2 = 0.86). The perceptibility thresholds for fitted S-shape curves were Δ E00 = 1.30 ( r2 = 0.74) and Δ E ab = 1.80 ( r2 = 0.70) and Δ E00 = 1.25 ( r2 = 0.75), and Δ E ab = 1.74 ( r2 = 0.71) for the TSK Fuzzy Approximation. The Δ L ′, Δ C ′, Δ H ′ values corresponding to a 50% acceptability threshold were Δ L ′ = 2.44, Δ C ′ = 3.15 and Δ H ′ = 3.24 respectively. Conclusions The CIEDE2000 color difference formula provided a better fit than CIELAB formula in the evaluation of color difference thresholds of dental ceramics. There was a statistically significant difference between perceptibility and acceptability thresholds for dental ceramics. The TSK Fuzzy Approximation has been proved to be a reliable alternative approach for the color threshold calculation procedure.
Increase of resistance to the application of benzalkonium chloride (BAC), peracetic acid (PA) and nisin during biofilm formation at 25 °C by three strains of
Listeria monocytogenes (CECT 911, CECT ...4032, CECT 5873 and BAC-adapted CECT 5873) in different scenarios was compared. For this purpose, resistance after 4 and 11-days of biofilm formation was quantified in terms of lethal dose 90% values (LD
90), determined according with a dose-response logistic mathematical model. Microscopic analyses after 4 and 11-days of
L. monocytogenes biofilm formation were also carried out. Results demonstrated a relation between the microscopic structure and the resistance to the assayed biocides in matured biofilms. The worst cases being biofilms formed by the strain 4032 (in both stainless steel and polypropylene), which showed a complex “
cloud-type” structure that correlates with the highest resistance of this strain against the three biocides during biofilm maturation. However, that increase in resistance and complexity appeared not to be dependent on initial bacterial adherence, thus indicating mature biofilms rather than planctonic cells or early-stage biofilms must be considered when disinfection protocols have to be optimized. PA seemed to be the most effective of the three disinfectants used for biofilms. We hypothesized both its high oxidizing capacity and low molecular size could suppose an advantage for its penetration inside the biofilm. We also demonstrated that organic material counteract with the biocides, thus indicating the importance of improving cleaning protocols. Finally, by comparing strains 5873 and 5873 adapted to BAC, several adaptative cross-responses between BAC and nisin or peracetic acid were identified.
The development of materials that can exhibit thermal resistance at very high temperatures, thus allowing them to be applied as catalysts and thermal insulators, amongst other possible uses, is a ...research subject of great interest. This is the case for hexaaluminates, a class of hexagonal aluminate compounds with a unique structure that are stable at very high temperatures up to 1600°C and exhibit exceptional resistance to sintering and thermal shock, thus making them attractive catalysts for high-temperature applications. In this review, the structure of hexaaluminates is presented first. The most recent advances in synthetic methods (sol-gel, reverse microemulsion, hydrothermal synthesis, carbon-templating, solution combustion synthesis, and freeze-drying methods) are discussed subsequently, with the aim of maximizing textural properties and including in their structure metals known to be active in catalytic applications, such as combustion of CH
4
, partial oxidation, and dry reforming of CH
4
to produce synthetic gas, and the decomposition of N
2
O. Finally, other applications, such as their function as a thermal barrier, are also addressed.
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