Inhalation exposure to particulate matter in rooms with underfloor air distribution

This work investigated the personal exposure to indoor particulate matters using the intake fraction metric and provided a possible way to trace the particle inhaled from an indoor particle source. A turbulence model validated by the particle measurements in a room with underfloor air distribution (UFAD) system was used to predict the indoor particle concentrations. Inhalation intake fraction of indoor particles was defined and evaluated in two rooms equipped with the UFAD, i.e., the experimental room and a small office. According to the exposure characteristics and a typical respiratory rate, the intake fraction was determined in two rooms with a continuous and episodic (human cough) source of particles, respectively. The findings showed that the well-mixing assumption of indoor air failed to give an accurate estimation of inhalation exposure and the average concentration at return outlet or within the overall room could not relate well the intake fraction to the amount of particle emitted from an indoor source.

Restricting microbial exposure in early life negates the immune benefits associated with gut colonization in environments of high microbial diversity

Background: Acquisition of the intestinal microbiota in early life corresponds with the development of the mucosal immune system. Recent work on caesarean-delivered infants revealed that early microbial composition is influenced by birthing method and environment. Furthermore, we have confirmed that early-life environment strongly influences both the adult gut microbiota and development of the gut immune system. Here, we address the impact of limiting microbial exposure after initial colonization on the development of adult gut immunity. Methodology/Principal Findings: Piglets were born in indoor or outdoor rearing units, allowing natural colonization in the immediate period after birth, prior to transfer to high-health status isolators. Strikingly, gut closure and morphological development were strongly affected by isolator-rearing, independent of indoor or outdoor origins of piglets. Isolator-reared animals showed extensive vacuolation and disorganization of the gut epithelium, inferring that normal gut closure requires maturation factors present in maternal milk. Although morphological maturation and gut closure were delayed in isolatorreared animals, these hard-wired events occurred later in development. Type I IFN, IL-22, IL-23 and Th17 pathways were increased in indoor-isolator compared to outdoor-isolator animals during early life, indicating greater immune activation in pigs originating from indoor environments reflecting differences in the early microbiota. This difference was less apparent later in development due to enhanced immune activation and convergence of the microbiota in all isolator-reared animals. This correlated with elevation of Type I IFN pathways in both groups, although T cell pathways were still more affected in indoor-reared animals. Conclusions/Significance: Environmental factors, in particular microbial exposure, influence expression of a large number of immune-related genes. However, the homeostatic effects of microbial colonization in outdoor environments require sustained microbial exposure throughout development. Gut development in high-hygiene environments negatively impacts on normal succession of the gut microbiota and promotes innate immune activation which may impair immune homeostasis.

Pesticide-handling practices of smallholder coffee farmers in Eastern Jamaica

Pesticide use among smallholder coffee producers in Jamaica has been associated with significant occupational health effects. Research on pesticide handling practices, however, has been scarce, especially in eastern Jamaica. This explorative study aims at filling this gap and provides a first basis to develop effective interventions to promote a safer pesticide use. A random sample of 81 coffee farmers was surveyed. The majority of farmers reported to suffer from at least one health symptom associated with pesticide handling, but safety practices were scarcely adopted. There was also the risk that other household members and the wider local community are exposed to pesticides. The lack of training on pesticide management, the role of health services and the cost for protective equipment seemed to be the most significant factors that influence current pesticide handling practices in eastern Jamaica. Further research is recommended to develop a systemic understanding of farmer’s behaviour to provide a more solid basis for the development of future intervention programmes.

Variation in rice cadmium related to human exposure.

Cereal grains are the dominant source of cadmium in the human diet, with rice being to the fore. Here we explore the effect of geographic, genetic, and processing (milling) factors on rice grain cadmium and rice consumption rates that lead to dietary variance in cadmium intake. From a survey of 12 countries on four continents, cadmium levels in rice grain were the highest in Bangladesh and Sri Lanka, with both these countries also having high per capita rice intakes. For Bangladesh and Sri Lanka, there was high weekly intake of cadmium from rice, leading to intakes deemed unsafe by international and national regulators. While genetic variance, and to a lesser extent milling, provide strategies for reducing cadmium in rice, caution has to be used, as there is environmental regulation as well as genetic regulation of cadmium accumulation within rice grains. For countries that import rice, grain cadmium can be controlled by where that rice is sourced, but for countries with subsistence rice economies that have high levels of cadmium in rice grain, agronomic and breeding strategies are required to lower grain cadmium.

Aluminium and breast cancer: sources of exposure, tissue measurements and mechanisms of toxicological actions on breast biology

This review examines recent evidence linking exposure to aluminium with the aetiology of breast cancer. The human population is exposed to aluminium throughout daily life including through diet, application of antiperspirants, use of antacids and vaccination. Aluminium has now been measured in a range of human breast structures at higher levels than in blood serum and experimental evidence suggests that the tissue concentrations measured have the potential to adversely influence breast epithelial cells including generation of genomic instability, induction of anchorage-independent proliferation and interference in oestrogen action. The presence of aluminium in the human breast may also alter the breast microenvironment causing disruption to iron metabolism, oxidative damage to cellular components, inflammatory responses and alterations to the motility of cells. The main research need is now to investigate whether the concentrations of aluminium measured in the human breast can lead in vivo to any of the effects observed in cells in vitro and this would be aided by the identification of biomarkers specific for aluminium action.

Exposure to parabens at the concentration of maximal proliferative response increases migratory and invasive activity of human breast cancer cells in vitro

Alkyl esters of p–hydroxybenzoic acid (parabens) are widely used as preservatives in personal care products, foods and pharmaceuticals. Their oestrogenic activity, their measurement in human breast tissue and their ability to drive proliferation of oestrogen-responsive human breast cancer cells has opened a debate on their potential to influence breast cancer development. Since proliferation is not the only hallmark of cancer cells, we have investigated the effects of exposure to parabens at concentrations of maximal proliferative response on migratory and invasive properties using three oestrogen-responsive human breast cancer cell lines (MCF-7, T-47-D, ZR-75-1). Cells were maintained short-term (1 week) or long-term (20±2 weeks) in phenol-red-free medium containing 5% charcoal-stripped serum with no addition, 10-8M 17-oestradiol, 1-5x10-4M methylparaben, 10-5M n-propylparaben or 10-5M n-butylparaben. Long-term exposure (20±2 weeks) of MCF-7 cells to methylparaben, n-propylparaben or n-butylparaben increased migration as measured using a scratch assay, time-lapse microscopy and xCELLigence technology: invasive properties were found to increase in matrix degradation assays and migration through matrigel on xCELLigence. Western immunoblotting showed an associated downregulation of E-cadherin and -catenin in the long-term paraben-exposed cells which could be consistent with a mechanism involving epithelial to mesenchymal transition. Increased migratory activity was demonstrated also in long-term paraben-exposed T-47-D and ZR-75-1 cells using a scratch assay and time-lapse microscopy. This is the first report that in vitro, parabens can influence not only proliferation but also migratory and invasive properties of human breast cancer cells.

From farmers’ perspective : pesticide use and pest control

Many studies have shown that farmers in developing countries often overuse pesticides and do not adopt safety practices. Policies and interventions to promote a safer use of pesticides are often based on a limited understanding of the farmers’ own perspective of pesticide use. This often results in ineffective policies and the persistence of significant pesticide-related health and environmental problems, especially in developing countries. This chapter explores potentials and limitations of different approaches to study pesticide use in agriculture from the farmers’ perspective. In contrast to the reductionist and mono-disciplinary approaches often adopted, this chapter calls for integrative methodological approaches to provide a realistic and thorough understanding of the farmers’ perspective on pesticide use and illustrates the added value of such an approach with three case studies of pesticide use in Iran, India, and Colombia.

Televised Whorf: cognitive restructuring in advanced foreign language learners as a function of audio-visual media exposure

The encoding of goal-oriented motion events varies across different languages. Speakers of languages without grammatical aspect (e.g., Swedish) tend to mention motion endpoints when describing events, e.g., “two nuns walk to a house,”, and attach importance to event endpoints when matching scenes from memory. Speakers of aspect languages (e.g., English), on the other hand, are more prone to direct attention to the ongoingness of motion events, which is reflected both in their event descriptions, e.g., “two nuns are walking.”, and in their non-verbal similarity judgements. This study examines to what extent native speakers of Swedish (n = 82) with English as a foreign language (FL) restructure their categorisation of goal-oriented motion as a function of their English proficiency and experience with the English language (e.g., exposure, learning). Seventeen monolingual native English speakers from the United Kingdom (UK) were engaged for comparison purposes. Data on motion event cognition were collected through a memory-based triads matching task, in which a target scene with an intermediate degree of endpoint orientation was matched with two alternative scenes with low and high degrees of endpoint orientation, respectively. Results showed that the preference among the Swedish speakers of L2 English to base their similarity judgements on ongoingness rather than event endpoints was correlated with their use of English in their everyday lives, such that those who often watched television in English approximated the ongoingness preference of the English native speakers. These findings suggest that event cognition patterns may be restructured through the exposure to FL audio-visual media. The results thus add to the emerging picture that learning a new language entails learning new ways of observing and reasoning about reality.

Learning to think in a second language: effects of proficiency and length of exposure in English learners of German

The aim of the current study is to investigate motion event cognition in second language learners in a higher education learning context. Based on recent findings showing that speakers of grammatical aspect languages like English attend less to the endpoint (goal) of events than speakers of non-aspect languages like Swedish in a nonverbal categorization task involving working memory (Athanasopoulos & Bylund, 2013; Bylund & Athanasopoulos, this issue), the current study asks whether native speakers of an aspect language start paying more attention to event endpoints when learning a non-aspect language. Native English and German (a non-aspect language) speakers, and English learners of L2 German, who were pursuing studies in German language and literature at an English university, were asked to match a target scene with intermediate degree of endpoint orientation with two alternate scenes with low and high degree of endpoint orientation, respectively. Results showed that, when compared to the native English speakers, the learners of German were more prone to base their similarity judgements on endpoint saliency, rather than ongoingness, primarily as a function of increasing L2 proficiency and year of university study. Further analyses revealed a non-linear relationship between length of L2 exposure and categorization patterns, subserved by a progressive strengthening of the relationship between L2 proficiency and categorization as length of exposure increased. These findings present evidence that cognitive restructuring may occur through increasing experience with an L2, but also suggest that this relationship may be complex, and unfold over a long period of time.

Enhancing consumer liking of low salt tomato soup over repeated exposure by herb and spice seasonings

There is strong evidence for the link between high dietary sodium and increased risk of cardiovascular disease which drives the need to reduce salt content in foods. In this study, herb and spice blends were used to enhance consumer acceptability of a low salt tomato soup (0.26% w/w). Subjects (n=148) scored their liking of tomato soup samples over five consecutive days. The first and last days were pre-and post-exposure visits where all participants rated three tomato soup samples; standard, low salt and low salt with added herbs and spices. The middle 3 days were the repeated exposure phase where participants were divided into three balanced groups; consuming the standard soup, the low salt soup, or the low salt soup with added herbs and spices. Reducing salt in the tomato soup led to a significant decline in consumer acceptability, and incorporating herbs and spices did not lead to an immediate enhancement in liking. However, inclusion of herbs and spices enhanced the perception of the salty taste of the low salt soup to the same level as the standard. Repeated exposure to the herbs and spice-modified soup led to a significant increase in the overall liking and liking of flavour, texture and aftertaste of the soup, whereas no changes in liking were observed for the standard and low salt tomato soups over repeated exposure. Moreover, a positive trend in increasing the post-exposure liking of the herbs and spices soup was observed. The findings suggest that the use of herbs and spices is a useful approach to reduce salt content in foods; however, herbs and spices should be chosen carefully to complement the food as large contrasts in flavour can polarise consumer liking.

The effect of light exposure on the degradation of latent fingerprints on brass surfaces: the use of silver electroless deposition as a visualization technique

We have studied the degradation of sebaceous fingerprints on brass surfaces using silver electroless deposition (SED) as a visualization technique. We have stored fingerprints on brass squares either (i) in a locked dark cupboard or (ii) in glass-filtered natural daylight for periods of 3 h, 24 h, 1 week, 3 weeks, and 6 weeks. We find that fingerprints on brass surfaces degrade much more rapidly when kept in the light than they do under dark conditions with a much higher proportion of high-quality prints found after 3 or 6 weeks of aging when stored in the dark. This process is more marked than for similar fingerprints on black PVC surfaces. Identifiable prints can be achieved on brass surfaces using both SED and cyanoacrylate fuming (CFM). SED is quick and straightforward to perform. CFM is more time-consuming but is versatile and can be applied to a wider range of metal surfaces than SED, for example brass surfaces which have been coated by a lacquer.

Assessment of plant uptake models used in exposure assessment tools for soils contaminated with organic pollutants

The aim of this study was to evaluate and improve the accuracy of plant uptake models for neutral hydrophobic organic pollutants (1 < logKOW < 9, −8 < logKAW < 0) used in regulatory exposure assessment tools, using uncertainty and sensitivity analyses. The models considered were RAIDAR, EUSES, CSOIL, CLEA, and CalTOX. In this research, CSOIL demonstrated the best performance of all five exposure assessment tools for root uptake from polluted soil in comparison with observed data, but no model predicted shoot uptake well. Recalibration of the transpiration and volatilisation parameters improved the performance of CSOIL and CLEA. The dominant pathway for shoot uptake simulated differed according to the properties of the chemical under consideration; those with a higher air–water partition coefficient were transported into shoots via the soil-air-plant pathway, while chemicals with a lower octanol–water partition coefficient and air–water partition coefficient were transported via the root. The soil organic carbon content was a particularly sensitive parameter in each model and using a site specific value improved model performance.

A toxicokinetic model for thiamethoxam in rats: implications for higher-tier risk assessment

Risk assessment for mammals is currently based on external exposure measurements, but effects of toxicants are better correlated with the systemically available dose than with the external administered dose. So for risk assessment of pesticides, toxicokinetics should be interpreted in the context of potential exposure in the field taking account of the timescale of exposure and individual patterns of feeding. Internal concentration is the net result of absorption, distribution, metabolism and excretion (ADME). We present a case study for thiamethoxam to show how data from ADME study on rats can be used to parameterize a body burden model which predicts body residue levels after exposures to LD50 dose either as a bolus or eaten at different feeding rates. Kinetic parameters were determined in male and female rats after an intravenous and oral administration of 14C labelled by fitting one-compartment models to measured pesticide concentrations in blood for each individual separately. The concentration of thiamethoxam in blood over time correlated closely with concentrations in other tissues and so was considered representative of pesticide concentration in the whole body. Body burden model simulations showed that maximum body weight-normalized doses of thiamethoxam were lower if the same external dose was ingested normally than if it was force fed in a single bolus dose. This indicates lower risk to rats through dietary exposure than would be estimated from the bolus LD50. The importance of key questions that should be answered before using the body burden approach in risk assessment, data requirements and assumptions made in this study are discussed in detail.

Using an individual-based model to select among alternative foraging strategies of woodpigeons: data support a memory-based model with a flocking mechanism

Population modelling is increasingly recognised as a useful tool for pesticide risk assessment. For vertebrates that may ingest pesticides with their food, such as woodpigeon (Columba palumbus), population models that simulate foraging behaviour explicitly can help predicting both exposure and population-level impact. Optimal foraging theory is often assumed to explain the individual-level decisions driving distributions of individuals in the field, but it may not adequately predict spatial and temporal characteristics of woodpigeon foraging because of the woodpigeons’ excellent memory, ability to fly long distances, and distinctive flocking behaviour. Here we present an individual-based model (IBM) of the woodpigeon. We used the model to predict distributions of foraging woodpigeons that use one of six alternative foraging strategies: optimal foraging, memory-based foraging and random foraging, each with or without flocking mechanisms. We used pattern-oriented modelling to determine which of the foraging strategies is best able to reproduce observed data patterns. Data used for model evaluation were gathered during a long-term woodpigeon study conducted between 1961 and 2004 and a radiotracking study conducted in 2003 and 2004, both in the UK, and are summarised here as three complex patterns: the distributions of foraging birds between vegetation types during the year, the number of fields visited daily by individuals, and the proportion of fields revisited by them on subsequent days. The model with a memory-based foraging strategy and a flocking mechanism was the only one to reproduce these three data patterns, and the optimal foraging model produced poor matches to all of them. The random foraging strategy reproduced two of the three patterns but was not able to guarantee population persistence. We conclude that with the memory-based foraging strategy including a flocking mechanism our model is realistic enough to estimate the potential exposure of woodpigeons to pesticides. We discuss how exposure can be linked to our model, and how the model could be used for risk assessment of pesticides, for example predicting exposure and effects in heterogeneous landscapes planted seasonally with a variety of crops, while accounting for differences in land use between landscapes.