Consumer behaviour survey for assessing exposure from consumer products: a feasibility study.

Evaluating chemical exposures from consumer products is an essential part of chemical safety assessments under REACH and may also be important to demonstrate compliance with consumer product legislation. Modelling of consumer exposure needs input information on the substance (e.g. vapour pressure), the product(s) containing the substance (e.g. concentration) and on consumer behaviour (e.g. use frequency and amount of product used). This feasibility study in Germany investigated methods for conducting a consumer survey in order to identify and retrieve information on frequency, duration, use amounts and use conditions for six example product types (four mixtures, two articles): hand dishwashing liquid, cockpit spray, fillers, paints and lacquers, shoes made of rubber or plastic, and ball-pens/pencils. Retrospective questionnaire methods (Consumer Product Questionnaire (CPQ), and Recall-Foresight Questionnaire (RFQ)) as well as protocol methods (written reporting by participants and video documentation) were used. A combination of retrospective questionnaire and written protocol methods was identified to provide valid information in a resource-efficient way. Relevant information, which can readily be used in exposure modelling, was obtained for all parameters and product types investigated. Based on the observations in this feasibility study, recommendations are given for designing a large consumer survey.

Don't Lose Your Brain at Work - The Role of Recurrent Novelty at Work in Cognitive and Brain Aging.

Cognitive and brain aging is strongly influenced by everyday settings such as work demands. Long-term exposure to low job complexity, for instance, has detrimental effects on cognitive functioning and regional gray matter (GM) volume. Brain and cognition, however, are also characterized by plasticity. We postulate that the experience of novelty (at work) is one important trigger of plasticity. We investigated the cumulative effect of recurrent exposure to work-task changes (WTC) at low levels of job complexity on GM volume and cognitive functioning of middle-aged production workers across a time window of 17 years. In a case-control study, we found that amount of WTC was associated with better processing speed and working memory as well as with more GM volume in brain regions that have been associated with learning and that show pronounced age-related decline. Recurrent novelty at work may serve as an 'in vivo' intervention that helps counteracting debilitating long-term effects of low job complexity.

Proteins from the FLOWERING LOCUS T-like subclade of the PEBP family act antagonistically to regulate floral initiation in tobacco.

Flowering is an important agronomic trait that often depends on the integration of photoperiod, vernalization, gibberellin and/or autonomous signaling pathways by regulatory proteins such as FLOWERING LOCUS T (FT), a member of the phosphatidylethanolamine-binding protein (PEBP) family. Six PEBP family proteins control flowering in the model plant Arabidopsis thaliana, and their regulatory functions are well established, but variation in the number and structural diversity of PEBPs in different species means their precise functions must be determined on a case-by-case basis. We isolated four novel FT-like genes from Nicotiana tabacum (tobacco), and determined their expression profiles in wild-type plants and their overexpression phenotypes in transgenic plants. We found that all four genes were expressed in leaves under short-day conditions, and at least NtFT3 expression was restricted to phloem companion cells. We also found that the NtFT1, NtFT2 and NtFT3 proteins are floral inhibitors (atypical for FT-like proteins), whereas only NtFT4 is a floral inducer. We were unable to detect the expression of these genes under long-day conditions, suggesting that all four tobacco FT-like proteins may control flowering in response to short days. Phylogenetic analysis of PEBP family proteins and their functions in different solanaceous species confirmed that gene duplication and divergence within the FT-like clade has led to the evolution of antagonistic regulators that may help to fine-tune floral initiation in response to environmental cues.

Suitability of the limit dose in evaluating reproductive toxicity of substances and preparations.

An oral dose of 1000 mg/kg body weight/day is mentioned in Organisation for Economic Cooperation and Development (OECD) and European Union (EU) guidelines as a default maximum dose in limit tests for studies on reproductive toxicity. This paper investigated whether upper range human exposure data from the workplace are supportive of this limit dose as an upper limit of possible human exposure. To this end, published exposure data as well as data from the database MEGA of the German "Berufsgenossenschaften" were evaluated. These data indicate that exposure concentrations in the range of 500 to 2000 mg/m(3) (time-weighted averages) can be considered high human exposures to volatile compounds. Inhalation exposure to aerosols and dermal exposure result in lower dose levels. By applying suitable extrapolation factors, it was concluded that occupational exposures up to 325 mg/m(3) can reliably be assessed with limit tests using a dose level of 1000 mg/kg/day. The limit dose has been proposed for use in the EU as a starting point to derive specific concentration limits for hazard classification of preparations containing reproductive toxicants, with the objective to consider the potency of the substances. This analysis shows that for some groups of chemicals, instead of the limit dose, the putative maximum levels of human exposure should be taken into account when deriving concentration limits for the classification of preparations. Furthermore, possible deviations from a linear correlation between concentration in the preparation and exposure should be considered.