Effect of Increasing Low Dose Simplexin Exposure in Cattle consuming Pimelia trychostachya

Pimelea species (or desert riceflower) are small native plants endemic to the drier inland pastoral regions of Australia, which cause a unique syndrome in grazing cattle characterised by submandibular oedema and oedema in the brisket area as a result of right-sided heart failure attributed to the toxin simplexin. Field evidence suggests that poisoning can occur through minor, inadvertent consumption of Pimelea plant material, but the minimum simplexin intake required to induce Pimelea poisoning is not known. In this study, mild Pimelea poisoning was induced at a daily dose of 12.5 mg Pimelea/kg bodyweight per day, equivalent to 2.5 µg simplexin/kg bodyweight per day, demonstrating the high potential toxicity of these plant species. Effects in all animals diminished with prolonged low dose feeding and we postulate that these animals developed mechanisms for detoxifying simplexin, 1, possibly through rumen bacteria adaptation or activation of liver enzymes.

Hanging drop: An in vitro air toxic exposure model using human lung cells in 2D and 3D structures

Using benzene as a candidate air toxicant and A549 cells as an in vitro cell model, we have developed and validated a hanging drop (HD) air exposure system that mimics an air liquid interface exposure to the lung for periods of 1 h to over 20 days. Dose response curves were highly reproducible for 2D cultures but more variable for 3D cultures. By comparing the HD exposure method with other classically used air exposure systems, we found that the HD exposure method is more sensitive, more reliable and cheaper to run than medium diffusion methods and the CULTEX (R) system. The concentration causing 50% of reduction of cell viability (EC50) for benzene, toluene, p-xylene, m-xylene and o-xylene to A549 cells for 1 h exposure in the HD system were similar to previous in vitro static air exposure. Not only cell viability could be assessed but also sub lethal biological endpoints such as DNA damage and interleukin expressions. An advantage of the HD exposure system is that bioavailability and cell concentrations can be derived from published physicochemical properties using a four compartment mass balance model. The modelled cellular effect concentrations EC50(cell) for 1 h exposure were very similar for benzene, toluene and three xylenes and ranged from 5 to 15 mmol/kg(dry weight) which corresponds to the intracellular concentration of narcotic chemicals in many aquatic species, confirming the high sensitivity of this exposure method. (C) 2013 Elsevier B.V. All rights reserved.

Mixture Effects of Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) to Lung Carcinoma Cells via a Hanging Drop Air Exposure System

A recently developed hanging drop air exposure system for toxicity studies of volatile chemicals was applied to evaluate the cell viability of lung carcinoma A549 cells after 1 h and 24 h of exposure to benzene, toluene, ethylbenzene and xylenes (BTEX) as individual compounds and mixtures of 4 or 6 components. The cellular chemical concentrations causing 50% reduction of cell viability (EC50) were calculated use a mass balance model and came to 17, 12, 11, 9, 4 and 4 mmol/kg cell dry weight for benzene, toluene, ethylbenzene, m-xylene, o-xylene and p-xylene respectively after 1 h of exposure. The EC50 decreased by a factor of four after 24 h of exposure. All mixture effects were best described by the mixture toxicity model of concentration addition, which is valid for chemicals with the same mode of action. Good agreement with the model predictions were found for benzene, toluene, ethylbenzene and m-xylene at four different representative fixed concentration ratios after 1 h of exposure but lower agreement to mixture prediction was obtained after 24 h of exposure. A recreated car exhaust mixture, which involved the contribution of the more toxic p-xylene and o-xylene, yielded an acceptable but lower quality prediction as well.

Use of pooled samples to assess human exposure to parabens, benzophenone-3 and triclosan in Queensland, Australia

Parabens, benzophenone-3 and triclosan are common ingredients used as preservatives, ultraviolet radiation filters and antimicrobial agents, respectively. Human exposure occurs through consumption of processed food and use of cosmetics and consumer products. The aim of this study was to provide a preliminary characterisation of exposure to selected personal care product chemicals in the general Australian population. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n= 24 pools of 100). Concentrations of free and total (sum of free plus conjugated) species of methyl, ethyl, propyl and butyl paraben, benzophenone-3 and triclosan were quantified using isotope dilution tandem mass spectrometry; with geometric means 232, 33.5, 60.6, 4.32, 61.5 and 87.7. ng/mL, respectively. Age was inversely associated with paraben concentration, and females had concentrations approximately two times higher than males. Total paraben and benzophenone-3 concentrations are significantly higher than reported worldwide, and the average triclosan concentration was more than one order of magnitude higher than in many other populations. This study provides the first data on exposure of the general Australian population to a range of common personal care product chemical ingredients, which appears to be prevalent and warrants further investigation.

Insights into PBDE uptake, body burden, and elimination gained from Australian age–Concentration trends observed shortly after peak exposure

Background Population pharmacokinetic models combined with multiple sets of age– concentration biomonitoring data facilitate back-calculation of chemical uptake rates from biomonitoring data. Objectives We back-calculated uptake rates of PBDEs for the Australian population from multiple biomonitoring surveys (top-down) and compared them with uptake rates calculated from dietary intake estimates of PBDEs and PBDE concentrations in dust (bottom-up). Methods Using three sets of PBDE elimination half-lives, we applied a population pharmacokinetic model to the PBDE biomonitoring data measured between 2002–2003 and 2010–2011 to derive the top-down uptake rates of four key PBDE congeners and six age groups. For the bottom-up approach, we used PBDE concentrations measured around 2005. Results Top-down uptake rates of Σ4BDE (the sum of BDEs 47, 99, 100, and 153) varied from 7.9 to 19 ng/kg/day for toddlers and from 1.2 to 3.0 ng/kg/day for adults; in most cases, they were—for all age groups—higher than the bottom-up uptake rates. The discrepancy was largest for toddlers with factors up to 7–15 depending on the congener. Despite different elimination half-lives of the four congeners, the age–concentration trends showed no increase in concentration with age and were similar for all congeners. Conclusions In the bottom-up approach, PBDE uptake is underestimated; currently known pathways are not sufficient to explain measured PBDE concentrations, especially in young children. Although PBDE exposure of toddlers has declined in the past years, pre- and postnatal exposure to PBDEs has remained almost constant because the mothers’ PBDE body burden has not yet decreased substantially.

Assessing the combined effect of asbestos exposure and smoking on lung cancer: a Bayesian approach

We review the literature on the combined association between lung cancer and two environmental exposures, asbestos exposure and smoking, and explore a Bayesian approach to assess evidence of interaction between the exposures. The meta-analysis combines separate indices of additive and multiplicative relationships and multivariate relative risk estimates. By making inferences on posterior probabilities we can explore both the form and strength of interaction. This analysis may be more informative than providing evidence to support one relation over another on the basis of statistical significance. Overall, we find evidence for a more than additive and less than multiplicative relation.

Low temperature exposure of root system and inflorescence affected flowering and fruit set in 'Chardonnay' grapevines (Vitis vinifera)

The mechanisms by which low temperature affects flowering and fruit set of grapevines are poorly understood, as is the specific response of the grapevine root system and inflorescence to low temperature effects that reduce fruit set. This study aimed to determine the responses of the root system and inflorescence of the grapevine 'Chardonnay' to low temperature (10 degrees C) during flowering, and considered the possible mechanisms of low temperature effects on those parts. Temperature treatments of 10 degrees C or 20 degrees C were imposed to potted 'Chardonnay' grapevines in a glasshouse for up to two weeks during the early stages of flowering. When the root system alone was exposed to 10 degrees C (with the rest of the plant at 20 degrees C) during flowering, the number of attached berries and percentage fruit set were significantly reduced by 50 % than when the root system alone was exposed to 20 degrees C. Whereas, exposure of the inflorescence alone to 10 degrees C (with the rest of the plant at 20 degrees C) delayed flowering, allowed rachis to grow longer, and increased both the number of attached berries (from 22 to 62 per vine) and fruit set (from 8 % to, 20 %), than when the inflorescence alone was exposed to 20 degrees C. This study will enhance our understanding of the possible mechanisms of low temperature effects on grapevine fruit set and productivity.

Analysis and prevention of extreme vibration in high speed craft - A research framework

Extreme vibration has been reported for small, high speed craft in the maritime sector, with performance and health threatening effects on boat operators and crew. Musculoskeletal injuries are an enduring problem for high speed craft passengers. Spinal or joint injuries and neurological disorders may occur from repetitive pounding over rough water, continued vibration and single impact events. The risk from whole body vibration (WBV) induced through the small vessels mainly depends on time spent on the craft, which can’t be changed in a military scenario; as well as the number of shocks and jolts, and their magnitude and frequency. In the European Union for example, physical agents directives require all employers to control exposure to a number of physical agents including noise and vibration. The EC Vibration Directive 2002/44/EC then sets out regulations for the control of health and safety risks from the exposure of workers to hand arm vibration (HAV) and WBV in the workplace. Australia has exposure standards relating to WBV, AS 2670.1-2001 – Evaluation of human exposure to whole body vibration. This standard is identical to the ISO 2631-1:1997, Mechanical vibration and shock – Evaluation of human exposure to whole-body vibration. Currently, none of the jurisdictions in Australia have specific regulations for vibration exposures in workplaces. However vibration is mentioned to varying degrees in their general regulations, codes of practice and guidance material. WBV on high speed craft is normally caused by “continuous 'hammering' from short steep seas or wind against tide conditions. Shock on High Speed Craft is usually caused by random impacts. Military organisations need the knowledge to make informed decisions regarding their marine operations, compliance with legislation and potentially harmful health effects, and develop and implement appropriate counter-measures. Marine case studies in the UK such as published MAIB (Marine Accident Investigation Branch) reports show injuries that have occurred in operation, and subsequent MCA (Maritime Coastguard Agency) guidance is provided (MGN 436 (M+F), WHOLE-BODY VIBRATION: Guidance on Mitigating Against the Effects of Shocks and Impacts on Small Vessels. MCA, 2011). This paper proposes a research framework to study the origin, impact and pathways for prevention of WBV in small, high speed craft in a maritime environment.

Infection and pathology in Queensland grouper, Epinephelus lanceolatus, (Bloch), caused by exposure to Streptococcus agalactiae via different routes

Since 2007, 96 wild Queensland groupers, Epinephelus lanceolatus, (Bloch), have been found dead in NE Australia. In some cases, Streptococcus agalactiae (Group B Streptococcus, GBS) was isolated. At present, a GBS isolate from a wild grouper case was employed in experimental challenge trials in hatchery-reared Queensland grouper by different routes of exposure. Injection resulted in rapid development of clinical signs including bilateral exophthalmia, hyperaemic skin or fins and abnormal swimming. Death occurred in, and GBS was re-isolated from, 98% fish injected and was detected by PCR in brain, head kidney and spleen from all fish, regardless of challenge dose. Challenge by immersion resulted in lower morbidity with a clear dose response. Whilst infection was established via oral challenge by admixture with feed, no mortality occurred. Histology showed pathology consistent with GBS infection in organs examined from all injected fish, from fish challenged with medium and high doses by immersion, and from high-dose oral challenge. These experimental challenges demonstrated that GBS isolated from wild Queensland grouper reproduced disease in experimentally challenged fish and resulted in pathology that was consistent with that seen in wild Queensland grouper infected with S. agalactiae.

Wavefront filter for double-exposure holographic interferometry

Measurements of small phase shifts by double-exposure holographic interferometry are facilitated, and ambiguities in the sign of the phase shift eliminated, by introducing a background pattern of interference fringes. A simple and reliable optical system for this purpose utilizing a rotating wedge is described, with which fringes of any desired orientation and spacing can conveniently be obtained. It is shown how this system can be used under certain conditions for measurements of small mechanical deformations.

Effect of drying, storage temperature and air exposure on astaxanthin stability from Haematococcus pluvialis

Astaxanthin is a powerful antioxidant with various health benefits such as prevention of age-related macular degeneration and improvement of the immune system, liver and heart function. To improve the post-harvesting stability of astaxanthin used in food, feed and nutraceutical industries, the biomass of the high astaxanthin producing alga Haematococcus pluvialis was dried by spray- or freeze-drying and under vacuum or air at − 20 °C to 37 °C for 20 weeks. Freeze-drying led to 41 higher astaxanthin recovery compared to commonly-used spray-drying. Low storage temperature (− 20 °C, 4 °C) and vacuum-packing also showed higher astaxanthin stability with as little as 12.3 ± 3.1 degradation during 20 weeks of storage. Cost-benefit analysis showed that freeze-drying followed by vacuum-packed storage at − 20 °C can generate AUD600 higher profit compared to spray-drying from 100 kg H. pluvialis powder. Therefore, freeze-drying can be suggested as a mild and more profitable method for ensuring longer shelf life of astaxanthin from H. pluvialis.

Evaluating the effects of international exposure from networks ties and mimetic pressure on clustered SMEs in Brazil

Research on the internationalisation of small and medium-sized enterprises (SMEs) has received increasing attention in recent years due to the important role they play in today’s economic environment. Internationalisation prompting, or awareness, is an already recognised phase of the innovation-related stages model (I-model). This phase of awareness is closely related to the international exposure that a firm may experience during the occasion when it realises its competitors are already internationalising. Although the literature has discussed the various forms in which international exposure may happen, there has been limited attention given to the extent of its effect on the internationalisation of clustered SMEs that behave according to the I-Model. This study will assess the applicability of the I-Model in a dynamic, competitive and co-operative setting of an industrial cluster. It also evaluates the impact (if any) of international exposure derived from networks and the mimetic pressure that these firms may experience due to their embeddedness in an industrial cluster. Results from this study will indicate the effectiveness of the improved adapted model that will provide a richer insight for both academic researchers and policy makers.

Infection and pathology in Queensland grouper, Epinephelus lanceolatus, (Bloch), caused by exposure to Streptococcus agalactiae via different routes

Since 2007, 96 wild Queensland groupers, Epinephelus lanceolatus, (Bloch), have been found dead in NE Australia. In some cases, Streptococcus agalactiae (Group B Streptococcus, GBS) was isolated. At present, a GBS isolate from a wild grouper case was employed in experimental challenge trials in hatchery-reared Queensland grouper by different routes of exposure. Injection resulted in rapid development of clinical signs including bilateral exophthalmia, hyperaemic skin or fins and abnormal swimming. Death occurred in, and GBS was re-isolated from, 98% fish injected and was detected by PCR in brain, head kidney and spleen from all fish, regardless of challenge dose. Challenge by immersion resulted in lower morbidity with a clear dose response. Whilst infection was established via oral challenge by admixture with feed, no mortality occurred. Histology showed pathology consistent with GBS infection in organs examined from all injected fish, from fish challenged with medium and high doses by immersion, and from high-dose oral challenge. These experimental challenges demonstrated that GBS isolated from wild Queensland grouper reproduced disease in experimentally challenged fish and resulted in pathology that was consistent with that seen in wild Queensland grouper infected with S. agalactiae.

Light exposure and eye growth in childhood

PURPOSE The purpose of this study was to examine the relationship between objectively measured ambient light exposure and longitudinal changes in axial eye growth in childhood. METHODS A total of 101 children (41 myopes and 60 nonmyopes), 10 to 15 years of age participated in this prospective longitudinal observational study. Axial eye growth was determined from measurements of ocular optical biometry collected at four study visits over an 18-month period. Each child’s mean daily light exposure was derived from two periods (each 14 days long) of objective light exposure measurements from a wrist-worn light sensor. RESULTS Over the 18-month study period, a modest but statistically significant association between greater average daily light exposure and slower axial eye growth was observed (P ¼ 0.047). Other significant predictors of axial eye growth in this population included children’s refractive error group (P < 0.001), sex (P < 0.01), and age (P < 0.001). Categorized according to their objectively measured average daily light exposure and adjusting for potential confounders (age, sex, baseline axial length, parental myopia, nearwork, and physical activity), children experiencing low average daily light exposure (mean daily light exposure: 459 6 117 lux, annual eye growth: 0.13 mm/y) exhibited significantly greater eye growth than children experiencing moderate (842 6 109 lux, 0.060 mm/y), and high (1455 6 317 lux, 0.065 mm/y) average daily light exposure levels (P ¼ 0.01). CONCLUSIONS In this population of children, greater daily light exposure was associated with less axial eye growth over an 18-month period. These findings support the role of light exposure in the documented association between time spent outdoors and childhood myopia.

Ambient light exposure influences childhood eye growth

• Although there is evidence that outdoor activity is an important factor involved in the development of childhood refractive error,1,2 the mechanism underlying the association between more outdoor activity and less myopia in childhood is not clear. • In this prospective longitudinal study, the relationship between objectively measured ambient light exposure and eye growth in childhood was examined.