Acute aquatic toxicity of arsenic-based chemical warfare agents to Daphnia magna

Sea dumping of chemical warfare (CW) took place worldwide during the 20th century. Submerged CW included metal bombs and casings that have been exposed for 50-100 years of corrosion and are now known to be leaking. Therefore, the arsenic-based chemical warfare agents (CWAs), pose a potential threat to the marine ecosystems. The aim of this research was to support a need for real-data measurements for accurate risk assessments and categorization of threats originating from submerged CWAs. This has been achieved by providing a broad insight into arsenic-based CWAs acute toxicity in aquatic ecosystems. Standard tests were performed to provide a solid foundation for acute aquatic toxicity threshold estimations of CWA: Lewisite, Adamsite, Clark I, phenyldichloroarsine (PDCA), CWA-related compounds: TPA, arsenic trichloride and four arsenic-based CWA degradation products. Despite their low solubility, during the 48 h exposure, all CWA caused highly negative effects on Daphnia magna. PDCA was very toxic with 48 h D. magna LC50 at 0.36 mu g x L-1- and Lewisite with EC50 at 3.2 mu g x L-1 . Concentrations at which no immobilization effects were observed were slightly above the analytical Limits of Detection (LOD) and Quantification (LOQ). More water-soluble CWA degradation products showed no effects at concentrations up to 100 mg x L-1.Peer reviewe

Lower Pain Threshold While Seeing a Virtual Limb – Boundary Conditions for Visual Analgesia Effect

Background: Observing one’s own body has been shown to influence pain perception—a phenomenon called visual analgesia. The effect was originally obtained using a mirror reflection of one’s own hand and later replicated with prosthetic and virtual hands. Most studies show increased pain thresholds during visual analgesia, but the opposite effect can be obtained by inducing ownership illusion over a limb that looks wounded. We tested the hypothesis that a resilient-looking virtual limb would lead to an increased pain threshold. Methods: Eighty-eight students (Mage = 21.4, SDage = 2.98) participated in a within-group experimental design study (natural hand virtual reality [VR], marble hand VR, and non-VR control). In both VR conditions, a visuo-tactile synchronous stimulation was used to elicit the illusion of embodiment. Pressure pain stimulus was applied to the forearm. Dependent variables were: pressure pain threshold, pain intensity and self-reported embodiment. Results: There were significant differences between the control condition and the Natural Hand VR (V = 647, p < .0001), and between the control condition and the Marble Hand VR (V = 947.5, p < .005), but not between the Natural Hand and Marble Hand conditions (V = 1428.5, p = .62). Contrary to our predictions, pain threshold was higher in the control condition. Pain intensity differences were not significant. Conclusions: We obtained a significant effect in the opposite direction than predicted. Such results may mean that the visual analgesia effect is more context-dependent than previously thought. We discuss methodological differences between the paradigm used in this study and paradigms reported in the literature as a possible explanation

Distraction of attention with the use of virtual reality. Influence of the level of game complexity on the level of experienced pain

: Research done in recent years shows that Virtual Reality (VR) can be an effective tool for distracting attention from pain. The purpose of this study was to test how the complexity of Virtual Environment (VE) influences the experienced intensity of thermal pain stimuli. A within-subjects design experiment was conducted, using cold pressor test for pain stimulation. Research was done on 31 students of Wroclaw Universities. Participants played games created for the purpose of the study, using head mounted displays and movement sensors. Two Virtual Environments differing in the level of complexity and non-VR control condition were used. The order of all conditions was counterbalanced. Participants reported significantly lower pain intensity (Visual Analogue Scale) after playing the high complexity game, compared to the low complexity game. There were also significant differences between non-VR control condition and high complexity game, but not between non-VR and low complexity game. The pain tolerance (measured by time of keeping the hand in cold water) was significantly higher in both VR conditions comparing to non-VR conditions. However, no significant differences between VE’s were found in pain tolerance ratings. Results of this study provide preliminary evidence that game complexity can be related to pain experience during VR interventions

Virtual Reality Could Improve Exercise Performance on a Stationary Bike

The present study aimed to investigate the effects of manipulating visual information about one’s movement in Virtual Reality (VR) during physical training on a stationary bike. In the first experiment, the participants’ (N=30) task was to cycle on a stationary bike while embodying a virtual avatar. Fifteen participants experienced the Slow condition, in which a virtual avatar cycled at the constant speed of 15km/h, while the other fifteen participants experienced the Fast condition, in which a virtual avatar cycled at the constant speed of 35km/h. In the second experiment, we tested whether introducing agency (i.e., linking real-life cycling speed with the cycling speed of a virtual avatar), would improve exercise performance. Participants (N=31) experienced counterbalanced conditions: Faster optic flow (avatar’s speed was 15% faster than the participants’ real cycling speed), and Slower optic flow (avatar’s speed was 15% slower than the participants’ real cycling speed). Results showed that all participants increased their cycling speed when experiencing altered cycling speed of a virtual avatar compared with their baselines, but in the first experiment, participants cycled faster in the faster optic flow condition, while in the second experiment, when participants controlled the virtual avatar’s cycling speed, there were no differences between the Fast and Slow conditions. Participants described the cycling in VR as a pleasant experience. The present study suggests that the addition of Virtual Reality during exercise training may increase cycling performance

Gamma-H2AX foci in cells exposed to a mixed beam of X-rays and alpha particles

BACKGROUND: Little is known about the cellular effects of exposure to mixed beams of high and low linear energy transfer radiation. So far, the effects of combined exposures have mainly been assessed with clonogenic survival or cytogenetic methods, and the results are contradictory. The gamma-H2AX assay has up to now not been applied in this context, and it is a promising tool for investigating the early cellular response to mixed beam irradiation. PURPOSE: To determine the dose response and repair kinetics of gamma-H2AX ionizing radiation-induced foci in VH10 human fibroblasts exposed to mixed beams of (241)Am alpha particles and X-rays. RESULTS: VH10 human fibroblasts were irradiated with each radiation type individually or both in combination at 37°C. Foci were scored for repair kinetics 0.5, 1, 3 and 24 h after irradiation (one dose per irradiation type), and for dose response at the 1 h time point. The dose response effect of mixed beam was additive, and the relative biological effectiveness for alpha particles (as compared to X-rays) was of 0.76 ± 0.52 for the total number of foci, and 2.54 ± 1.11 for large foci. The repair kinetics for total number of foci in cells exposed to mixed beam irradiation was intermediate to that of cells exposed to alpha particles and X-rays. However, for mixed beam-irradiated cells the frequency and area of large foci were initially lower than predicted and increased during the first 3 hours of repair (while the predicted number and area did not). CONCLUSIONS: The repair kinetics of large foci after mixed beam exposure was significantly different from predicted based on the effect of the single dose components. The formation of large foci was delayed and they did not reach their maximum area until 1 h after irradiation. We hypothesize that the presence of low X-ray-induced damage engages the DNA repair machinery leading to a delayed DNA damage response to the more complex DNA damage induced by alpha particles

Mobile virtual reality distraction reduces needle pain and stress in children?

Virtual reality (VR) technology is a remarkably effective method for distracting attention from painful stimuli. This is particularly important for children who undergo painful and stressful medical treatments. The main aim of the present study was to examine whether the type of VR distraction had an effect on reducing pain and stress in children during a short blood sampling treatment, and to investigate the effectiveness of mobile VR.Fifty-seven patients of a pediatric nephrology clinic (Mage = 12, range: 7–17) participated in a between-group experimental design study. Participants in the treatment group (active vs passive VR) underwent a venipuncture procedure with VR distraction. Mobile VR (Samsung gear) was used in this study. Participants in the active VR experimental condition played a game based on the multiple object tracking task paradigm. In the passive VR experimental condition, participants watched a film similar to the presented game. All participants rated their pain and stress levels on the Visual Analogue Scale and completed a short questionnaire.Both VR groups reported significantly lower pain and stress intensity than the control group. When comparing the two experimental groups, no statistically significant differences were found, although participants differed in their level of perceived pain and stress, with greater benefits in the active VR. The present study focused on comparing the effect sizes of active and passive VR interventions. Additionally, the study confirmed feasibility of using Multiple Object Tracking paradigm as a method of attention distraction in VR

Mobile virtual reality distraction reduces needle pain and stress in children?

Virtual reality (VR) technology is a remarkably effective method for distracting attention from painful stimuli. This is particularly important for children who undergo painful and stressful medical treatments. The main aim of the present study was to examine whether the type of VR distraction had an effect on reducing pain and stress in children during a short blood sampling treatment, and to investigate the effectiveness of mobile VR.Fifty-seven patients of a pediatric nephrology clinic (Mage = 12, range: 7–17) participated in a between-group experimental design study. Participants in the treatment group (active vs passive VR) underwent a venipuncture procedure with VR distraction. Mobile VR (Samsung gear) was used in this study. Participants in the active VR experimental condition played a game based on the multiple object tracking task paradigm. In the passive VR experimental condition, participants watched a film similar to the presented game. All participants rated their pain and stress levels on the Visual Analogue Scale and completed a short questionnaire.Both VR groups reported significantly lower pain and stress intensity than the control group. When comparing the two experimental groups, no statistically significant differences were found, although participants differed in their level of perceived pain and stress, with greater benefits in the active VR. The present study focused on comparing the effect sizes of active and passive VR interventions. Additionally, the study confirmed feasibility of using Multiple Object Tracking paradigm as a method of attention distraction in VR