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Aerial Image Segmentation of Nematode-Affected Pine Trees with U-Net Convolutional Neural Network
No full textPine wood nematode disease, commonly referred to as pine wilt, poses a grave threat to forest health, leading to profound ecological and economic impacts. Originating from the pine wood nematode, this disease not only causes the demise of pine trees but also casts a long shadow over the entire forest ecosystem. The accurate identification of infected trees stands as a pivotal initial step in developing effective prevention and control measures for pine wilt. Nevertheless, existing identification methods face challenges in precisely determining the disease status of individual pine trees, impeding early detection and efficient intervention. In this study, we leverage the capabilities of unmanned aerial vehicle (UAV) remote sensing technology and integrate the VGG classical small convolutional kernel network with U-Net to detect diseased pine trees. This cutting-edge approach captures the spatial and characteristic intricacies of infected trees, converting them into high-dimensional features through multiple convolutions within the VGG network. This method significantly reduces the parameter count while enhancing the sensing range. The results obtained from our validation set are remarkably promising, achieving a Mean Intersection over Union (MIoU) of 81.62%, a Mean Pixel Accuracy (MPA) of 85.13%, an Accuracy of 99.13%, and an F1 Score of 88.50%. These figures surpass those obtained using other methods such as ResNet50 and DeepLab v3+. The methodology presented in this research facilitates rapid and accurate monitoring of pine trees infected with nematodes, offering invaluable technical assistance in the prevention and management of pine wilt disease
Ship Emissions as the Largest Contributor to Coastal Atmospheric Black Carbon at a Receptor Island in Southern China
No full textAtmospheric black carbon (BC) over coastal regions poses a threat in terms of both climate change and human health. However, the provenance of aerosol BC, particularly its subfractions (char-BC and soot-BC, which have different physicochemical properties), is poorly constrained. Here, we apportioned the sources of char-BC and soot-BC in year-round PM2.5 samples from a coastal receptor island off southern China. Char-BC dominated, accounting for 88.6 +/- 13.2% of the total BC. The two BC subfractions exhibited distinct seasonal variation patterns, which may be attributed to differences in their sources and hydrophilicity. Combustion of liquid fossil fuels, including bunker fuel, diesel, and gasoline, contributed more highly to soot-BC (71.4%) than to char-BC (53.9%). Conversely, combustion of solid fuels, including biomass and coal, contributed more highly to char-BC (44.6%) than to soot-BC (6.7%). Bunker fuel combustion, the dominant portion of ship emissions, was the largest contributor to total BC (46.0%), char-BC (45.2%), and soot-BC (56.4%). This indicates that marine ship emissions, rather than land-based sources including biomass and coal combustion, were the dominant source of atmospheric BC in coastal areas, highlighting the importance of controlling maritime ship emissions
Potential threats of microplastics and pathogenic bacteria to the immune system of the mussels <i>Mytilus galloprovincialis</i>
No full textAs one of the main components of marine pollution, microplastics (MPs) inevitably enter the mussel aquaculture environment. At the same time, pathogenic bacteria, especially pathogens such as Vibrio, can cause illness outbreaks, leading to large-scale death of mussels. The potential harm of MPs and pathogenic bacteria to bivalve remains unclear. This study designed two experiments (1) mussels (Mytilus galloprovincialis) were exposed to 100 particles/L or 1,000 particles/L polymethyl methacrylate (PMMA, 17.01 +/- 6.74 mu m) MPs and 1 x 107 CFU/mL Vibrio parahaemolyticus at the same time (14 days), and (2) mussels were exposed to 100 particles/L or 1,000 particles/L MPs for a long time (30 days) and then exposed to 1 x 107 CFU/mL V. parahaemolyticus to explore the effects of these two stresses on the mussel immune system. The results showed that after the combined exposure of V. parahaemolyticus and MPs, the lysosomal membrane stability of hemocytes decreased, lysozyme activity was inhibited, and hemocytes were induced to produce more lectins and defensins to fight pathogenic invasion. Longterm exposure to MPs caused a large amount of energy consumption in mussels, inhibited most of the functions of humoral immunity, increased the risk of mussel infection with pathogenic bacteria, and negatively affected mussel condition factor, the number of hemocytes, and the number of byssuses. Mussels may allocate more energy to deal with MPs and pathogenic bacterial infections rather than for growth. Above all, MPs exposure can affect mussel immune function or reduce its stress resistance, which in turn has an impact on mollusk farming
The role of different wind input, whitecap dissipation and quadruplet wave-wave interaction terms in wave evolution in Lake Michigan
No full textIn present study, the sensitivity of WAVEWATCH-III model to different wind sources, formulations for wind input, whitecap dissipation and quadruplet wave-wave interaction was investigated during both fair weather and extreme condition of Hurricane Sandy in Lake Michigan. Wind data sets with finer spatial resolution (GLERL and GEM) led to better agreement with in-situ data, while ERA5 with coarser spatial resolution underestimated wind speed both in deep and shallow waters. Preparatory evaluation of model skill in reproducing wave bulk parameters indicated that the highest error was obtained when ST4 package and ERA5 wind data were employed in model. The calibration procedure was conducted by employing a combined error index. Simulated wave bulk parameters with optimum tuning values for GLERL and GEM wind data were in well agreement with in-situ data; however, GEM outperformed GLERL during extreme values of H s and T m in deep water buoys. Moreover, GLERL wind data slightly improved model skill in H s and T p estimation in shallow water buoys. Although more advanced methods were considered for quadruplet wave-wave interaction, DIA could be sufficiently reliable method for hindcasting wave bulk parameters. The DIA method systematically overestimated wave energy at low frequencies which was alleviated when GMD or GQM method was employed. Obtained directional wave spectra by using ST1 and ST6 packages combined with DIA were directionally broad as well as less energetic in peak frequency; however, GMD, GQM and WRT methods were led to more concentrated high energy content. In general, the quality and quantity of modeled wave spectra were in a reasonable agreement with observed one after model calibration
Shining light on carbon dots: Toward enhanced antibacterial activity for biofilm disruption
No full textIn spite of tremendous efforts dedicated to addressing bacterial infections and biofilm formation, the post-antibiotic ear continues to witness a gap between the established materials and an easily accessible yet biocompatible antibacterial reagent. Here we show carbon dots (CDs) synthesized via a single hydrothermal process can afford promising antibacterial activity that can be further enhanced by exposure to light. By using citric acid and polyethyleneimine as the precursors, the photoluminescence CDs can be produced within a one-pot, one-step hydrothermal reaction in only 2 h. The CDs demonstrate robust antibacterial properties against both Gram-positive and Gram-negative bacteria and, notably, a considerable enhancement of antibacterial effect can be observed upon photo-irradiation. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) when exposed to light, leading to an augmented reactive oxygen species level. The approach for disruption of biofilms and inhibition of biofilm formation by using the CDs has also been established. Our findings present a potential solution to combat antibacterial resistance and offer a path to reduce dependence on traditional antibiotics.
Shining carbon dots (CDs) produced by a single-step hydrothermal method can afford enhanced antibacterial activity against both Gram-positive and Gram-negative bacteria. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) under light irradiation, contributing to an augmented ROS level, facilitating disruption of biofilms and inhibition of biofilm formation. imag
Modeling Blue Crab (<i>Callinectes sapidus</i>) Larval Transport and Recruitment Dynamics in a Shallow Lagoon-Inlet-Coastal Ocean System
No full textBlue crab (Callinectes sapidus) supports lucrative Mid-Atlantic crustacean fisheries and plays an important role in estuarine ecology, so their larval transport and recruitment dynamics in the Maryland Coastal Bays system were investigated using simulated and observed surface drifters. Relative contributions of winds, tides, density gradients, and waves to larval recruitment success were identified during the spawning season, particularly under hurricane conditions in 2014. Based on temperature (e.g., 19-29 degrees C) and salinity conditions (e.g., 23-33 PSU), particles representing virtual blue crab larvae were released into the model domain from early June to late October 2014. During the spawning season, variations in the larval recruitment success caused by wind speed and direction, tides (e.g., affecting through inlets), density gradients (e.g., salinity variations), and surface gravity waves were 17%, 4%, -9%, and 17%, respectively. During Hurricane Arthur (2014), variability of self-recruitment success caused by density gradients are negligible while by other three factors are comparable at 3%-4%. Surface drifter experiments support the modeling results that larval recruitment success is strongly associated with the coastal circulation. The high (low) self-recruitment success in the Assawoman and Chincoteague Bays (Sinepuxent Bay) is related to the locally weak (strong) circulation; released larvae escape from inlets are likely recruited to southern Fenwick and northern Assateague Islands, and the coastal regions outside the Chincoteague Inlet. Understanding physical factors influencing larval recruitment success helps resource managers make informed decisions about habitat restoration and harvest regulations, in addition to seafood-related food security
Insight into mercury ion detection in environmental samples and imaging in living systems by a near-infrared fluorescent probe
No full textSince mercury could accumulate along with the food chains and undermine environment and human health, development of efficient mercury detection tools in water samples, plants and living systems is of great significance. In this work, we designed a hemicyanine-based fluorescent probe HCYS for mercury detection. The probe exhibited distinct near-infrared fluorescence intensity. Based on the spin orbit coupling effect and heavy atom effect of Hg2+, a significant fluorescent change was exhibited since Hg2+ chelated with the probe by inhibition of the intramolecular charge transfer process in HCYS. The limit of detection (LOD) was calculated to be 1.41 mu M. Exploiting the benefits of fast response time (less than 1 min), high selectivity and noninvasively track capacity, the probe has been applied in biological systems. The solid results proved that the probe HCYS is a powerful tool for Hg2+ imaging in living cells, zebrafish, pea spouts and water samples
Grain transportation and consumption reshapes the α-HCH exposure picture of China
No full textSocio-economic activities like food trade can increase the uncertainty of human risk of persistent organic pollutants (POPs). We compared the change in model predicted alpha-hexachlorocyclohexane (alpha-HCH) cancer risk (CR) with and without grain trade in mainland China. In scenario without grain logistics, alpha-HCH moved fast away from southern and southeastern China via northward atmospheric transport. However, the grain logistics from northeastern China delivers the alpha-HCH previously accumulated in northeastern sink back to densely populated areas in recent years, which enhance CR by >50 % in the southern seaboard of China. The northward movement of grain production center and recent grain deficiency in southern provinces induced by dietary pattern changes is identified as the major driving factors of the reversed transport of alpha-HCH. The finding highlights the potential of socio-economic activities that can otherwise offset the risk reduction effect of the geochemical cycle of POPs
Grain transportation and consumption reshapes the α-HCH exposure picture of China
No full textSocio-economic activities like food trade can increase the uncertainty of human risk of persistent organic pollutants (POPs). We compared the change in model predicted alpha-hexachlorocyclohexane (alpha-HCH) cancer risk (CR) with and without grain trade in mainland China. In scenario without grain logistics, alpha-HCH moved fast away from southern and southeastern China via northward atmospheric transport. However, the grain logistics from northeastern China delivers the alpha-HCH previously accumulated in northeastern sink back to densely populated areas in recent years, which enhance CR by >50 % in the southern seaboard of China. The northward movement of grain production center and recent grain deficiency in southern provinces induced by dietary pattern changes is identified as the major driving factors of the reversed transport of alpha-HCH. The finding highlights the potential of socio-economic activities that can otherwise offset the risk reduction effect of the geochemical cycle of POPs
Time Is Ripe for Targeting Per- and Polyfluoroalkyl Substances-Induced Hormesis: Global Aquatic Hotspots and Implications for Ecological Risk Assessment
No full textGlobally implemented ecological risk assessment (ERA) guidelines marginalize hormesis, a biphasic dose-response relationship characterized by low-dose stimulation and high-dose inhibition. The present study illuminated the promise of hormesis as a scientific dose-response model for ERA of per- and polyfluoroalkyl substances (PFAS) represented by perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). A total of 266 hormetic dose-response relationships were recompiled from 1237 observations, covering 30 species from nine representative taxonomic groups. The standardized hormetic amplitudes followed the log-normal probability distribution, being subject to the limits of biological plasticity but independent of stress inducers. The SHapley Additive exPlanations algorithm revealed that the target endpoint was the most important variable explaining the hormetic amplitudes. Subsequently, quantitative frameworks were established to incorporate hormesis into the predicted no-effect concentration levels, with a lower induction dose and a zero-equivalent point but a broader hormetic zone for PFOS. Realistically, 10,117 observed concentrations of PFOA and PFOS were gathered worldwide, 4% of which fell within hormetic zones, highlighting the environmental relevance of hormesis. Additionally, the hormesis induction potential was identified in other legacy and emerging PFAS as well as their alternatives and mixtures. Collectively, it is time to incorporate the hormesis concept into PFAS studies to facilitate more realistic risk characterizations