EIU-Net: Enhanced feature extraction and improved skip connections in U-Net for skin lesion segmentation.

Skin lesion segmentation is a computer-aided diagnosis method for quantitative analysis of melanoma that can improve efficiency and accuracy. Although many methods based on U-Net have achieved tremendous success, they still cannot handle challenging tasks well due to weak feature extraction. In response to skin lesion segmentation, a novel method called EIU-Net is proposed to tackle the challenging task. To capture the local and global contextual information, we employ inverted residual blocks and an efficient pyramid squeeze attention (EPSA) block as the main encoders at different stages, while atrous spatial pyramid pooling (ASPP) is utilized after the last encoder and the soft-pool method is introduced for downsampling. Also, we propose a novel method named multi-layer fusion (MLF) module to effectively fuse the feature distributions and capture significant boundary information of skin lesions in different encoders to improve the performance of the network. Furthermore, a reshaped decoders fusion module is used to obtain multi-scale information by fusing feature maps of different decoders to improve the final results of skin lesion segmentation. To validate the performance of our proposed network, we compare it with other methods on four public datasets, including the ISIC 2016, ISIC 2017, ISIC 2018, and PH2 datasets. And the main metric Dice scores achieved by our proposed EIU-Net are 0.919, 0.855, 0.902, and 0.916 on the four datasets, respectively, outperforming other methods. Ablation experiments also demonstrate the effectiveness of the main modules in our proposed network. Our code is available at https://github.com/AwebNoob/EIU-Net.

The human and ecological risks of neonicotinoid insecticides in soils of an agricultural zone within the Pearl River Delta, South China.

Neonicotinoid insecticides (NIIs) are extensively used worldwide and frequently detected in the environment. The human and ecological risks associated with the occurrence of NIIs in agricultural zones are of high importance. The present study highlights the regional occurrence and human exposure risks of NIIs in agricultural soil within the Pearl River Delta (PRD), South China. Six neonicotinoids, i.e., imidacloprid, clothianidin, acetamiprid, imidaclothiz, dinotefuran, and flonicamid, were measured in 351 soil samples from Zengcheng, a typical agricultural zone. The soil samples were categorized into three groups based on cultivated plants: vegetables, rice, and fruits. At least one of these neonicotinoid insecticides was detected in 95% of the soil samples. The levels of ∑6NII (range (median)) were 0.26-390 (23), 0.26-280 (6.1), and 0.26-120 (5.0) ng g-1 dry weight in soil samples from vegetable farms, rice paddies, and fruit farms, respectively. Neonicotinoids were detected more frequently and at statistically higher concentrations in vegetable farms than in both rice paddies and fruit farms. This is likely ascribed to higher application frequencies of NIIs in vegetable farms due to higher planting frequencies. The hazard index values for human exposure to NIIs in the agricultural soils were all below 1, suggesting negligible non-cancer risks. The current residual levels of NIIs in the soils could however pose sub-lethal or acute effects to non-target terrestrial organisms such as earthworms. The present study suggests that more information is needed regarding NIIs contamination in soils from agricultural regions of South China to ensure that human and ecological risk from exposure to these compounds can be fully addressed.

Polybrominated diphenyl ethers and organophosphate esters flame retardants in play mats from China and the exposure risks for children.

A total of 41 play mats made from different raw materials, such as polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), chemical crosslinked polyethylene (XPE), and polyvinyl chloride (PVC), were obtained from Chinese markets and analyzed for flame retardants. Polybrominated diphenyl ethers (PBDEs) and their replacements, organophosphate esters (OPEs), were measured and the associated exposure risks for children were evaluated. The levels (range; median) of OPEs (6.6-7400; 200 ng g-1) were generally 1-2 orders of magnitude higher than those of PBDEs (0.13-72; 13 ng g-1), consistent with the production and usage trends of flame retardants. The concentrations of both PBDEs and OPEs were the lowest in XPE mats (0.13-5.6; 3.3 ng g-1 for PBDEs and 6.6-320; 47 ng g-1 for OPEs) compared to the other three types. Concentration comparison and compositional analysis suggested that PBDEs and OPEs in play mats were most probably from leaching of raw materials, during production, storage, and/or transport. Children's exposure to PBDEs and OPEs from play mats was estimated for three pathways, i.e., dermal contact, inhalation, and hand-to-mouth ingestion. The combined exposure was 5-6 orders of magnitude lower than the established reference dose values, suggesting no obvious health concern regarding the occurrence of PBDEs and OPEs in play mats. Nevertheless, selection of less contaminated, i.e., XPE mats among those under investigation, by consumers is strongly recommended to minimize any potential exposure risk.

Development and Validation of an Efficient Method for Processing Microplastics in Biota Samples.

The impacts of microplastics on aquatic ecosystems and biota are gaining attention globally. Although microplastics have been widely detected in biota, there currently are few standardized detection and identification methods. The present study developed a novel one-step digestion method which was evaluated with mussel and fish samples. This method employed nitric acid and hydrogen peroxide (HNO3 :H2 O2 = 4:1 by volume) as digestion reagents, which completely digested biota samples <5 g weight within 30 min at 50 °C. A density separation step was subsequently used to remove organic residues as necessary. The efficiency and suitability of this method were tested by spiking microplastics of 7 different types and of various sizes (1000, 900, 675, 300, 250, and 150 µm) into mussel and gastrointestinal tracts of fish. The recoveries of microplastics ranged from 90 to 100%. No significant changes in weight, surface area, and particle size (t test, p > 0.05) were observed for all tested polymers. Fourier transform infrared spectral analyses demonstrated that the method did not degrade any of the polymers except for polyethylene terephthalate. The method was demonstrated with mussel and fish samples collected from the Pearl River delta, south China, and was able to recover microplastics effectively. Overall, the present method is time-saving and easy to operate, with low procedural cross-contamination. The properties of microplastics recovered by the present method remained largely intact, greatly benefiting subsequent qualitative and quantitative analyses. Environ Toxicol Chem 2019;38:1400-1408. © 2019 SETAC.