Search

Biochemical responses of the mussel Mytilus coruscus exposed to different concentrations of titanium dioxide nanoparticles (nano-TiO 2 ) (0, 2.5, 10 mg L −1 ) and two pH levels (pH 8.1 and pH 7.3) for 14 days. Mussel responses were also investigated after a 7 days recovery period (pH 8.1 and no nanoparticle). Exposure to nano-TiO 2 led changes in antioxidant indexes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH)), biotransformation enzyme activity (GST) and malondialdehyde level (MDA) in gills and digestive glands. An increase in MDA level and a decrease in SOD and GSH activities were observed in gill of mussels exposed to 10 mg L −1 nano-TiO 2 . This effect was more severe in mussels kept at pH 7.3 as compared to pH 8.1. A different response was observed in the digestive gland as SOD, CAT and GSH levels increased in mussels exposed to nano-TiO 2 . These contrasting results in digestive glands and gills were only evident at high concentration of nano-TiO 2 and low pH. A 7 days recovery period was not sufficient to fully restore SOD, GPx, GST, GSH and MDA levels to levels before exposure to nano-TiO 2 and low pH. Overall, our results confirmed that seawater acidification modulates effects of nanoparticles in mussels, and that gills are more sensitive to these stressors as compared with digestive glands. [ABSTRACT FROM AUTHOR]

In this paper, we explore the spatial redundancy in continuous sign language recognition (CSLR), aiming to improve its efficiency. Despite recent advances in accuracy in CSLR, state-of-the-art CSLR methods typically require large amounts of computations and memory occupation, which are not friendly towards fast inference under limited computation/memory budgets. Based on a simple observation that not all frames are equally important for CSLR, we propose AdaSize to handle this problem by modeling the frame resolution decision as an end-to-end learnable task to save unnecessary computations. Specifically, a lightweight 2D convolutional neural network (CNN) is first used to quickly browse input frames under a low resolution (e.g., 112 × 112). These extracted coarse and cheap features are sent into a recurrent policy network to dynamically determine the desired resolution for each frame. Once the optimal resolution for each frame is decided, frames with different resolutions are fed into the following backbones to extract representative features. Finally, these features pass through a sequence of temporal modules and a classifier to predict sentences. Extensive experiments on four large-scale datasets, including PHOENIX14, PHOENIX14-T, CSL-Daily and CSL, demonstrate the effectiveness of AdaSize. AdaSize could consistently achieve comparable accuracy with state-of-the-art CSLR methods, with only 0.38 × computations, 0.41 × memory usage and 1.25 × throughput. Comparisons with commonly-used lightweight backbones and other efficient methods verify the superiority of AdaSize under similar computational/memory budgets. We finally plot the frame resolution decisions for AdaSize, hoping to provide insightful analysis of the inherent spatial redundancy in videos. • Sign language is the main communication tool of the hearing-impaired people in their daily life. • Current sign language systems consume large computational costs and own high inference latency. • A novel adaptive method to improve network efficiency by switching among various resolution. • Both online and offline ablations on the generalizability of the proposed method. [ABSTRACT FROM AUTHOR]

Increased production of engineered nanoparticles has raised extensive concern about the potential toxic effects on marine organisms living in estuarine and coastal environments. Meanwhile, salinity is one of the key environmental factors that may influence the physiological activities in flatfish species inhabiting in those waters due to fluctuations caused by freshwater input or rainfall. In this study, we investigated the oxidative stress and histopathological alteration of the juvenile Paralichthys olivaceus exposed to nano-TiO 2 (1 and 10 mg L −1 ) under salinities of 10 and 30 psu for 4 days. In the gills, Na + -K + -ATPase activity significantly deceased after 4 days 10 psu exposure without nano-TiO 2 compared with 1 day of acclimating the salinity from the normal salinity (30 psu) to 10 psu. Under this coastal salinity, low concentration (1 mg L −1 ) of nano-TiO 2 exerted significant impacts. In the liver, the activities of superoxide dismutase, catalase, the levels of lipid peroxide and malondialdehyde increased with nano-TiO 2 exposed under 30 psu. Such increase indicated an oxidative stress response. The result of the integrated biomarker responses showed that P. olivaceus can be adversely affected by high salinity and high concentration of nano-TiO 2 for a short-term (4 days) exposure. The histological analysis revealed the accompanying severe damages for the gill filaments. Principal component analysis further showed that the oxidative stress was associated with the nano-TiO 2 effect at normal salinity. These findings indicated that nano-TiO 2 and normal salinity exert synergistic effects on juvenile P. olivaceus , and low salinity plays a protective role in its physiological state upon short-term exposure to nano-TiO 2 . The mechanism of salinity mediating the toxic effects of NPs on estuarine fish should be further considered. [ABSTRACT FROM AUTHOR]

Increased production of engineered nanoparticles (NPs) has raised extensive concerns about the potential toxic effects on marine organisms. Extensive evidences documented the impact of ocean acidification (OA) on the physiology and fitness of bivalves. In the present study, we investigated the biochemical responses of the mussel Mytilus coruscus exposed to both nano-ZnO and low pH relevant for ocean acidification conditions for 14 d followed by a 7-d recovery period. Most biochemical indexes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), acid phosphatase (ACP) and alkaline phosphatase (ALP)) measured in gills and hemocytes were increased when the mussels were subject to low pH or high concentration of nano-ZnO, suggesting oxidative stress responses. No significant interactions between the two stressors were observed for most measured parameters. After a 1 week recovery period, low pH and nano-ZnO had less marked impact for SOD, GPx, ACP and ALP in hemocytes as compared to the end of the 14 d exposure. However, no recovery was observed in gills. Overall, our results suggest that both low pH and nano-ZnO induce an anti-oxidative response in Mytilus coruscus with gills being more sensitive than hemocytes. [ABSTRACT FROM AUTHOR]