Degassing of 3H/3He, CFCs and SF6 by denitrification: Measurements and two-phase transport simulations

The production of N2 gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of 3H/3He, CFCs and SF6 as groundwater age tracers under agricultural...

Surface effects in the acetylation of granular potato starch

The occurrence of surface effects in the acetylation of granular potato starch with acetic anhydride to degrees of substitution 0.04-0.2 was studied by two different approaches. The first approach involved the fractionation of granular starch acetates into five different size classes and analysis of their acetate content. Alternatively, two...

Screening and confirmation criteria for hormone residue analysis using liquid chromatography accurate mass time-of-flight, Fourier transform ion cyclotron resonance and orbitrap mass spectrometry techniques

An emerging trend is recognised in hormone and veterinary drug residue analysis from liquid chromatography tandem mass spectrometry (LC/MS/MS) based screening and confirmation towards accurate mass alternatives such as LC coupled with time-of-flight (TOF), Fourier transform ion cyclotron resonance (FTICR) or Fourier transform orbitrap (FT...

From dermal exposure to internal dose

Exposure scenarios form an essential basis for chemical risk assessment reports under the new EU chemicals regulation REACH (Registration, Evaluation, Authorisation and restriction of Chemicals). In case the dermal route of exposure is predominant, information on both exposure and dermal bioavailability is necessary for a proper risk assessment....

Modelling of migration from multi-layers and functional barriers: Estimation of parameters

Functional barriers form parts of multi-layer packaging materials, which are deemed to protect the food from migration of a broad range of contaminants, e.g. those associated with reused packaging. Often, neither the presence nor the identity of the contaminants is known, so that safety assessment of the materials has to rely on predictive tools...

Evaluation of migration models that might be used in support of regulations for food-contact plastics

Materials and articles intended to come into contact with food must be shown to be safe because they might interact with food during processing, storage and the transportation of foodstuffs. Framework Directive 89/109/EEC and its related specific Directives provide this safety basis for the protection of the consumer against inadmissible...

Net analyte signal based statistical quality control

Net analyte signal statistical quality control (NAS-SQC) is a new methodology to perform multivariate product quality monitoring based on the net analyte signal approach. The main advantage of NAS-SQC is that the systematic variation in the product due to the analyte (or property) of interest is separated from the remaining systematic variation...

Inhibition of zaleplon metabolism by cimetidine in the human liver: In vitro studies with subcellular fractions and precision-cut liver slices

The effect of cimetidine on the metabolism of zaleplon (ZAL) in human liver subcellular fractions and precision-cut liver slices was investigated. 2. ZAL was metabolized to a number of products including 5-oxo-ZAL (M2), which is known to be formed by aldehyde oxidase, N-desethyl-ZAL (DZAL), which is known to be formed by CYP3A forms, and N...

Influence of solvent absorption on the migration of Irganox 1076 from LDPE

The effect of solvent absorption on additive migration was studied by relating the diffusion coefficient (D) of Irganox 1076 to the maximum solvent absorption of different solvents in low-density polyethylene (LDPE) film. Solvents tested were ethanol, isopropanol, isooctane, ethylacetate, cyclohexane, tributyrin, tricaprylin and olive oil....

Horseradish peroxidase-catalyzed oligomerization of ferulic acid on a template of a tyrosine-containing tripeptide

Ferulic acid (FA) is an abundantly present phenolic constituent of plant cell walls. Kinetically controlled incubation of FA and the tripeptide Gly-Tyr-Gly (GYG) with horseradish peroxidase and H2O2 yielded a range of new cross-linked products. Two predominant series of hetero-oligomers of FA linked by dehydrogenation to the peptidyl tyrosine...

Encephalitogenic and immunogenic potential of the stress protein αB-crystallin in Biozzi ABH (H-2A(g7)) mice

The stress protein αB-crystallin is an immunodominant antigen in multiple sclerosis (MS)-affected myelin for human T cells and is expressed at elevated levels in MS lesions. Using bovine αB-crystallin and synthetic peptides based on mouse αB-crystallin the ability of this stress protein to induce experimental allergic encephalomyelitis (EAE) was...

An equiratio mixture model for non-additive components: A case study for aspartame/acesulfame-K mixtures

The Equiratio Mixture Model predicts the psychophysical function for an equiratio mixture type on the basis of the psychophysical functions for the unmixed components. The model reliably estimates the sweetness of mixtures of sugars and sugar-alchohols, but is unable to predict intensity for aspartame/sucrose mixtures. In this paper, the...

Use of factorial designs in combination toxicity studies

The use of factorial designs, in which n chemicals are studied at x(n) dose levels (x treatment groups), has been put forward as one of the valuable statistical approaches for hazard assessment of chemical mixtures. Very recently a '25 study' was presented to describe interactions between the carcinogenic activity of five polycyclic aromatic...