controlled exposure
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2022 ◽  
Vol 174 ◽  
pp. 113194
Author(s):  
J.W. Durban ◽  
B.L. Southall ◽  
J. Calambokidis ◽  
C. Casey ◽  
H. Fearnbach ◽  
...  

2021 ◽  
Vol 3 (2) ◽  
pp. 89-98
Author(s):  
Andreea Cozea ◽  
◽  
Gheorghita Tanase ◽  
Mihaela Neagu ◽  

Complex studies were performed combining macroscopic and biochemical analyzes of selected biomonitors, exposed in exposure systems outdoor with mixtures of pollutants as well as controlled exposure with certain concentrations of pollutants in fumigation chambers. In this study, the following plant species were used as bioindicators: Nicotiana tabacum, Petunia hybrida, Ricinus comunis, Trifolium pretense. The exposure plant samples were compared with control samples of biomonitors maintained under standardized conditions in the climate chamber. Classical methods of biochemistry combined with those of exposure biomonitoring have led to the completion of knowledge about the ways of action of plants to pollution. The analysis of some of the antioxidant compounds that are representing a structural class of chemicals (enzymes) with a wide range of biological functions, with the role of free radical inhibition, was performed. Many of the constituent compounds in certain cell types, also called active compounds, in this case, polyphenols are present in the body of some plant species. Polyphenol's presence in organisms, that are not usually present or are in normal quantities, is caused by stress, (pollution being a stress factor). Large amounts of polyphenols in plants are also given by the presence of pollutants in the environment. Through these extensive combined studies, it has been demonstrated that pollution can be a degenerative factor at the biochemical and physiological level, at the plant tissue level, with irreversible effects.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 1-1
Author(s):  
Tawni N Williams ◽  
Angela R Green-Miller

Abstract Welfare status for any species is dependent upon an animal’s ability to cope with its environment. Environmental conditions, animal husbandry, and overall health are major components that contribute to managing livestock species with quality animal welfare. Previous approaches intending to create more robust animals have applied genetic selection, nutritional programming, or advancements in facilities. Engineered resilience, the approach explored here, represents: (a) the ability to identify certain physiological biomarkers, behaviors, and environmental stressors that contribute to the individual’s response to a challenge; and (b) manipulate them in a targeted way with well-timed and controlled exposure to improve outcomes of a challenge to homeostasis (i.e. improve fitness with prior conditioning). Foundational understanding of natural adaptation in response to challenge reveals that some animals emerge from a challenge with greater coping abilities and others fail to thrive. By determining which animals have natural resilience and exploring the factors that created desired outcomes, scenarios can be identified to initiate resilience in susceptible animals. Such responses can then be stimulated through the development of managerial techniques. This project was conducted by reviewing published literature with the goal of identifying more refined areas of study for future research in engineered resilience in livestock species. Potential for application of this concept includes building thermal resilience, social resilience, and disease resilience.


2021 ◽  
Vol 5 (CHI PLAY) ◽  
pp. 1-25
Author(s):  
Julian Frommel ◽  
Martin J. Dechant ◽  
Regan L. Mandryk

Social anxiety is a prevalent problem that affects many people with varying severity; digital exposure therapy-which involves controlled exposure to simulations of feared social situations alongside cognitive restructuring-can help treat patients with anxieties. However, the need to personalize exposure scenarios and simulate audiences are barriers to treating social anxieties through digital exposure. In this paper, we propose game streaming as an exposure therapy paradigm for social anxiety, supporting it with data from two studies. We first propose a framework describing requirements for exposure therapy and how game streaming can fulfill them. We select demand and performance visibility from these characteristics to showcase how to manipulate them for experiences of gradual exposure. With Study 1, we provide evidence for these characteristics and support for the framework by showing that a game's demand affected expected fear of streaming games. In Study 2, we show that the prospect of streaming led to elevated fear, a necessary property for effective exposure therapy. Further, we show that the effect of streaming on expected fear was similar for participants who can be considered socially anxious. These findings provide evidence for the essential effect of exposure therapy, which serves as a first step towards the validation of streaming as a social anxiety treatment. Our paper provides an initial, important step towards a novel, broadly applicable, and widely accessible digital approach for the treatment of social anxiety.


Biology Open ◽  
2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Siri L. Elmegaard ◽  
Birgitte I. McDonald ◽  
Jonas Teilmann ◽  
Peter T. Madsen

ABSTRACT Anthropogenic noise can alter marine mammal behaviour and physiology, but little is known about cetacean cardiovascular responses to exposures, despite evidence that acoustic stressors, such as naval sonars, may lead to decompression sickness. Here, we measured heart rate and movements of two trained harbour porpoises during controlled exposure to 6–9 kHz sonar-like sweeps and 40 kHz peak-frequency noise pulses, designed to evoke acoustic startle responses. The porpoises initially responded to the sonar sweep with intensified bradycardia despite unaltered behaviour/movement, but habituated rapidly to the stimuli. In contrast, 40 kHz noise pulses consistently evoked rapid muscle flinches (indicative of startles), but no behavioural or heart rate changes. We conclude that the autonomous startle response appears decoupled from, or overridden by, cardiac regulation in diving porpoises, whereas certain novel stimuli may motivate oxygen-conserving cardiovascular measures. Such responses to sound exposure may contribute to gas mismanagement for deeper-diving cetaceans.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jon Unosson ◽  
Mikael Kabéle ◽  
Christoffer Boman ◽  
Robin Nyström ◽  
Ioannis Sadiktsis ◽  
...  

Abstract Background Air pollution derived from combustion is associated with considerable cardiorespiratory morbidity and mortality in addition to environmental effects. Replacing petrodiesel with biodiesel may have ecological benefits, but impacts on human health remain unquantified. The objective was to compare acute cardiovascular effects of blended and pure biodiesel exhaust exposure against known adverse effects of petrodiesel exhaust (PDE) exposure in human subjects. In two randomized controlled double-blind crossover studies, healthy volunteers were exposed to PDE or biodiesel exhaust for one hour. In study one, 16 subjects were exposed, on separate occasions, to PDE and 30% rapeseed methyl ester biodiesel blend (RME30) exhaust, aiming at PM10 300 μg/m3. In study two, 19 male subjects were separately exposed to PDE and exhaust from a 100% RME fuel (RME100) using similar engine load and exhaust dilution. Generated exhaust was analyzed for physicochemical composition and oxidative potential. Following exposure, vascular endothelial function was assessed using forearm venous occlusion plethysmography and ex vivo thrombus formation was assessed using a Badimon chamber model of acute arterial injury. Biomarkers of inflammation, platelet activation and fibrinolysis were measured in the blood. Results In study 1, PDE and RME30 exposures were at comparable PM levels (314 ± 27 μg/m3; (PM10 ± SD) and 309 ± 30 μg/m3 respectively), whereas in study 2, the PDE exposure concentrations remained similar (310 ± 34 μg/m3), but RME100 levels were lower in PM (165 ± 16 μg/m3) and PAHs, but higher in particle number concentration. Compared to PDE, PM from RME had less oxidative potential. Forearm infusion of the vasodilators acetylcholine, bradykinin, sodium nitroprusside and verapamil resulted in dose-dependent increases in blood flow after all exposures. Vasodilatation and ex vivo thrombus formation were similar following exposure to exhaust from petrodiesel and the two biodiesel formulations (RME30 and RME100). There were no significant differences in blood biomarkers or exhaled nitric oxide levels between exposures. Conclusions Despite differences in PM composition and particle reactivity, controlled exposure to biodiesel exhaust was associated with similar cardiovascular effects to PDE. We suggest that the potential adverse health effects of biodiesel fuel emissions should be taken into account when evaluating future fuel policies. Trial registration ClinicalTrials.gov, NCT01337882/NCT01883466. Date of first enrollment March 11, 2011, registered April 19, 2011, i.e. retrospectively registered.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 423.1-423
Author(s):  
M. Volkov ◽  
A. S. B. Kampstra ◽  
K. van Schie ◽  
A. Kawakami ◽  
M. Tamai ◽  
...  

Background:Besides anti-citrullinated protein antibodies (ACPA), rheumatoid arthritis patients (RA) often display autoantibody reactivities against other post-translationally modified (PTM) proteins, more specifically carbamylated and acetylated proteins. Immunizing mice with one PTM results in an anti-modified protein antibody (AMPA) response recognizing multiple PTMs. Furthermore, human AMPA, isolated based on their reactivity to one PTM, cross-react with other PTMs at the monoclonal and polyclonal level. However, it is unclear whether the AMPA reactivity profile is “fixed” in time, or whether consecutive exposure to different PTMs can shape the evolving AMPA-response.Objectives:To investigate the evolution of the AMPA response in mice with controlled exposure to PTMs as well as in AMPA-positive humans.Methods:Mice were immunized with acetylated (or carbamylated) protein (ovalbumin) twice or cross-immunized with an acetylated and then a carbamylated protein (or vice versa) and their serum was analyzed for AMPA responses with ELISA using a different backbone protein (fibrinogen) bearing the same modifications. Longitudinally collected serum samples of human individuals at risk of RA and with early RA were tested to investigate the evolution of the AMPA responses in humans.Results:Mice immunized twice with either solely acetylated or solely carbamylated ovalbumin (AcOVA or CaOVA) developed reactivity against both acetylated and carbamylated antigens. Irrespective of the PTM used for the first immunization, a booster immunization with the other PTM resulted in increased titers to the second/booster PTM (Figure 1A), suggesting that immunization with a defined PTM-antigen leads to the generation of anti-PTM memory B cells able to cross-recognize other PTMs. Furthermore, immunizing with CaOVA and boosting with AcOVA (or vice versa) skewed the overall AMPA-response profile towards a relatively higher reactivity against the “booster” PTM (Figure 1B). Human data also illustrated dynamic changes in AMPA reactivity profiles in both individuals at risk of RA and in early RA patients (not shown).Conclusion:The relationship between different reactivities within the AMPA response is dynamic. The initial exposure to a PTM antigen induces cross-reactive response that can be boosted by the same or other PTMs. The overall reactivity pattern can be skewed by subsequent exposure to other PTMs. These data might explain temporal changes in the reactivity profile of the AMPA response and point to the possibility that the PTM responsible for the initiation of the AMPA response may differ from the PTM predominantly recognized later in time.Disclosure of Interests:None declared


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Andrea Valsesia ◽  
Jeremie Parot ◽  
Jessica Ponti ◽  
Dora Mehn ◽  
Rita Marino ◽  
...  

AbstractPlastic particulates in the environment pose an increasing concern for regulatory bodies due to their potential risk to higher organisms (including humans) as they enter the food chain. Nanoplastics (defined here as smaller than 1 μm) are particularly challenging to detect and analyze at environmentally relevant concentrations and in biological matrices. The tunicate Ciona Robusta is an effective bioindicator for microplastics and nanoplastic contamination in the marine environment, due to its capacity to filter substantial volumes of water and to accumulate particulates. In this proof-of-principle study that demonstrates a complete methodology, following controlled exposure using spiked samples of a model nanoplastic (100 nm diameter polystyrene spheres) the nanoparticles were separated from an enzymatically digested biological matrix, purified and concentrated for analysis. The described method yields an approximate value for nanoplastic concentration in the organism (with a limit of detection of 106 particles/organism, corresponding to 1 ng/g) and provides the chemical composition by Raman spectroscopy. Furthermore, this method can be extended to other biological matrices and used to quantitatively monitor the accumulation of nanoplastics in the environment and food chain.


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