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Kang L, Zhu M, Zhu G, Xu H, Zou W, Xiao M, Guo C, Zhang Y, Qin B. Decreasing denitrification rates poses a challenge to further decline of nitrogen concentration in Lake Taihu, China. WATER RESEARCH 2024; 256:121565. [PMID: 38581985 DOI: 10.1016/j.watres.2024.121565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/29/2024] [Accepted: 04/01/2024] [Indexed: 04/08/2024]
Abstract
Nitrogen (N) concentrations in many lakes have decreased substantially in recent years due to external load reduction to mitigate harmful algal blooms. However, little attention has been paid to the linkage between the lakes' nitrogen removal efficiency and improved water quality in lakes, especially the variation of denitrification rate (DNR) under decreasing N concentrations. To understand the efficiency of N removal under improving water quality and its influence on the N control targets in Lake Taihu, a denitrification model based on in situ experimental results was developed and long-term (from 2007 to 2022) water quality and meteorological observations were used to estimate DNR and relate it to the amount of N removal (ANR) from the lake. The concentration of total nitrogen (TN) in Lake Taihu decreased from 3.28 mg L-1 to 1.41 mg L-1 from 2007 to 2022 but the reduction showed spatial heterogeneity. The annual mean DNR decreased from 45.6 μmol m-2 h-1 to 4.2 μmol m-2 h-1, and ANR decreased from 11.85×103 t yr-1 to 1.17×103 t yr-1 during the study years. N budget analysis suggested that the amount of N removed by denitrification accounted for 23.3 % of the external load in 2007, but decreased to only 4.0 % in 2022. Thus, the contribution of N removal by internal N cycling decreased significantly as water quality improved. Notably, the proportion of ANR in winter to total ANR increased from 14 % in 2007 to 23 % in 2022 due to warming. This could potentially lead to N deficiencies in spring and summer, thus limiting the availability of N to phytoplankton. A TN concentration of less than 1.0 mg L-1 in the lake and 1.5 mg L-1 in the inflowing lake zones in spring contribute to local N-limitation in Lake Taihu for cyanobacteria control. Our study revealed a general pattern that N removal efficiency decreases with improved water quality, which is instructive for eutrophic lakes in nitrogen management.
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Affiliation(s)
- Lijuan Kang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Mengyuan Zhu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Guangwei Zhu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Hai Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Wei Zou
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Man Xiao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Chaoxuan Guo
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Yunlin Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Boqiang Qin
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
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Mugani R, El Khalloufi F, Redouane EM, Haida M, Aba RP, Essadki Y, El Amrani Zerrifi S, Hejjaj A, Ouazzani N, Campos A, Grossart HP, Mandi L, Vasconcelos V, Oudra B. Unlocking the potential of bacterioplankton-mediated microcystin degradation and removal: A bibliometric analysis of sustainable water treatment strategies. WATER RESEARCH 2024; 255:121497. [PMID: 38555787 DOI: 10.1016/j.watres.2024.121497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/31/2024] [Accepted: 03/19/2024] [Indexed: 04/02/2024]
Abstract
Microcystins (MCs) constitute a significant threat to human and environmental health, urging the development of effective removal methods for these toxins. In this review, we explore the potential of MC-degrading bacteria as a solution for the removal of MCs from water. The review insights into the mechanisms of action employed by these bacteria, elucidating their ability to degrade and thus remove MCs. After, the review points out the influence of the structural conformation of MCs on their removal, particularly their stability at different water depths within different water bodies. Then, we review the crucial role played by the production of MCs in ensuring the survival and safeguarding of the enzymatic activities of Microcystis cells. This justifies the need for developing effective and sustainable methods for removing MCs from aquatic ecosystems, given their critical ecological function and potential toxicity to humans and animals. Thereafter, challenges and limitations associated with using MC-degrading bacteria in water treatment are discussed, emphasizing the need for further research to optimize the selection of bacterial strains used for MCs biodegradation. The interaction of MCs-degrading bacteria with sediment particles is also crucial for their toxin removal potential and its efficiency. By presenting critical information, this review is a valuable resource for researchers, policymakers, and stakeholders involved in developing sustainable and practical approaches to remove MCs. Our review highlights the potential of various applications of MC-degrading bacteria, including multi-soil-layering (MSL) technologies. It emphasizes the need for ongoing research to optimize the utilization of MC-degrading bacteria in water treatment, ultimately ensuring the safety and quality of water sources. Moreover, this review highlights the value of bibliometric analyses in revealing research gaps and trends, providing detailed insights for further investigations. Specifically, we discuss the importance of employing advanced genomics, especially combining various OMICS approaches to identify and optimize the potential of MCs-degrading bacteria.
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Affiliation(s)
- Richard Mugani
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco; National Center for Studies and Research on Water and Energy, Cadi Ayyad University, P.O. Box: 511, 40000 Marrakech, Morocco; Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Zur alten Fischerhuette 2, 14775 Stechlin, Germany
| | - Fatima El Khalloufi
- Natural Resources Engineering and Environmental Impacts Team, Multidisciplinary Research and Innovation Laboratory, Polydisciplinary Faculty of Khouribga, Sultan Moulay Slimane University of Beni Mellal, B.P.: 145, 25000, Khouribga, Morocco
| | - El Mahdi Redouane
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco
| | - Mohammed Haida
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco
| | - Roseline Prisca Aba
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco; National Center for Studies and Research on Water and Energy, Cadi Ayyad University, P.O. Box: 511, 40000 Marrakech, Morocco
| | - Yasser Essadki
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco
| | - Soukaina El Amrani Zerrifi
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco; Higher Institute of Nurses Professions and Health Techniques of Guelmim, Guelmim, Morocco
| | - Abdessamad Hejjaj
- National Center for Studies and Research on Water and Energy, Cadi Ayyad University, P.O. Box: 511, 40000 Marrakech, Morocco.
| | - Naaila Ouazzani
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco; National Center for Studies and Research on Water and Energy, Cadi Ayyad University, P.O. Box: 511, 40000 Marrakech, Morocco
| | - Alexandre Campos
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Zur alten Fischerhuette 2, 14775 Stechlin, Germany; Institute of Biochemistry and Biology, University of Potsdam, Maulbeeralle 2, 14469 Potsdam, Germany
| | - Laila Mandi
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco; National Center for Studies and Research on Water and Energy, Cadi Ayyad University, P.O. Box: 511, 40000 Marrakech, Morocco
| | - Vitor Vasconcelos
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal; Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
| | - Brahim Oudra
- Water, Biodiversity and Climate Change Laboratory, Faculty of Sciences Semlalia, Cadi Ayyad University, Av. Prince My Abdellah, P.O. Box 2390, Marrakech 40000, Morocco
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Li X, Li L, Huang Y, Wu H, Sheng S, Jiang X, Chen X, Ostrovsky I. Upstream nitrogen availability determines the Microcystis salt tolerance and influences microcystins release in brackish water. WATER RESEARCH 2024; 252:121213. [PMID: 38306752 DOI: 10.1016/j.watres.2024.121213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/20/2024] [Accepted: 01/26/2024] [Indexed: 02/04/2024]
Abstract
The occurrence of large Microcystis biomass in brackish waters is primarily caused by its downward transportation from the upstream freshwater lakes and reservoirs through rivers rather than due to in situ bloom formation. Factors that determine the survival of freshwater cyanobacteria in brackish waters have not been well investigated. Here, we studied the spatiotemporal variability of inorganic nitrogen in an upstream lake and conducted laboratory and in-situ experiments to assess the role of nitrogen availability on the salt tolerance of Microcystis and the release of microcystins. A series of field experiments were carried out during bloom seasons to evaluate the salt tolerance of natural Microcystis colonies. The salt tolerance threshold varied from 7 to 17 and showed a positive relationship with intracellular carbohydrate content and a negative relationship with nitrogen availability in water. In August when upstream nitrogen availability was lower, the Microcystis colonies could maintain their biomass even after a sudden increase in salinity from 4 to 10. Laboratory-cultivated Microcystis that accumulated higher carbohydrate content at lower nitrogen availability showed better cell survival at higher salinity. The sharp release of microcystins into the surrounding water occurred when salinity exceeded the salt tolerance threshold of the Microcystis. Thus, Microcystis with higher salt tolerance can accumulate more toxins in cells. The obtained results suggest that the cell survival and toxin concentration in brackish waters depend on the physiological properties of Microcystis formed in the upstream waters. Thus, the life history of Microcystis in upstream waters could have a significant impact on its salt tolerance in downstream brackish waters, where the ecological risk of the salt-tolerant Microcystis requires special and careful management in summer at low nitrogen availability.
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Affiliation(s)
- Xinlu Li
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Lei Li
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Yingying Huang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
| | - Haipeng Wu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Shiwen Sheng
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xinran Jiang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Xuechu Chen
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, 200241, China.
| | - Ilia Ostrovsky
- Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal 1495001, Israel
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Wei N, Chen A, Guo X, Zhang S, Song L, Gan N, Zheng L, Jia Y, Li J. Changes in nitrogen metabolism of phosphorus-starved bloom-forming cyanobacterium Microcystis aeruginosa: Implications for nutrient management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166832. [PMID: 37673240 DOI: 10.1016/j.scitotenv.2023.166832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/21/2023] [Accepted: 09/02/2023] [Indexed: 09/08/2023]
Abstract
The surplus of nitrogen plays a key role in the maintenance of cyanobacterial bloom when phosphorus has already been limited. However, the interplay between high nitrogen and low phosphorus conditions is not fully understood. Nitrogen metabolism is critical for the metabolism of cyanobacteria. Transcriptomic analysis in the present study suggested that nitrogen metabolism and ribosome biogenesis were the two most significantly changed pathways in long-term phosphorus-starved bloom-forming cyanobacteria Microcystis aeruginosa FACHB-905. Notably, the primary glutamine synthetase/glutamate synthase cycle, crucial for nitrogen metabolism, was significantly downregulated. Concurrently, nitrogen uptake showed a marked decrease due to reduced expression of nitrogen source transporters. The content of intracellular nitrogen reservoir phycocyanin also showed a drastic decrease upon phosphorus starvation. Our study demonstrated that long-term phosphorus-starved cells also suffered from nitrogen deficiency because of the reduction in nitrogen assimilation, which might be limited by the reduced ribosome biogenesis and the shortage of adenosine triphosphate. External nitrogen supply will not change the transcriptions of nitrogen metabolism-related genes significantly like that under phosphorus-rich conditions, but still help to maintain the survival of phosphorus-starved cells. The study deepens our understanding about the survival strategies of Microcystis cells under phosphorus starvation and the mutual dependence between nitrogen and phosphorus, which would provide valuable information for nutrient management in the eutrophicated water body.
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Affiliation(s)
- Nian Wei
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China
| | - Aifa Chen
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha 410013, China
| | - Xiaohe Guo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Shubing Zhang
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha 410013, China
| | - Lirong Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Nanqin Gan
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Lingling Zheng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yunlu Jia
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Jie Li
- Department of Cell Biology, School of Life Sciences, Central South University, Changsha 410013, China; Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha 410013, China.
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Yang Y, Wang H, Yan S, Wang T, Zhang P, Zhang H, Wang H, Hansson LA, Xu J. Chemodiversity of Cyanobacterial Toxins Driven by Future Scenarios of Climate Warming and Eutrophication. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11767-11778. [PMID: 37535835 DOI: 10.1021/acs.est.3c02257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Climate change and eutrophication are two environmental threats that can alter the structure of freshwater ecosystems and their service functions, but we know little about how ecosystem structure and function will evolve in future scenarios of climate warming. Therefore, we created different experimental climate scenarios, including present-day conditions, a 3.0 °C increase in mean temperature, and a "heatwaves" scenario (i.e., an increase in temperature variability) to assess the effects of climate change on phytoplankton communities under simultaneous stress from eutrophication and herbicides. We show that the effects of climate warming, particularly heatwaves, are associated with elevated cyanobacterial abundances and toxin production, driven by a change from mainly nontoxic to toxic Microcystis spp. The reason for higher cyanobacterial toxin concentrations is likely an increase in abundances because under the dual pressures of climate warming and eutrophication individual Microcystis toxin-producing ability decreased. Eutrophication and higher temperatures significantly increased the biomass of Microcystis, leading to an increase in the cyanobacterial toxin concentrations. In contrast, warming alone did not produce higher cyanobacterial abundances or cyanobacterial toxin concentrations likely due to the depletion of the available nutrient pool. Similarly, the herbicide glyphosate alone did not affect abundances of any phytoplankton taxa. In the case of nutrient enrichment, cyanobacterial toxin concentrations were much higher than under warming alone due to a strong boost in biomass of potential cyanobacterial toxin producers. From a broader perspective our study shows that in a future warmer climate, nutrient loading has to be reduced if toxic cyanobacterial dominance is to be controlled.
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Affiliation(s)
- Yalan Yang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan 570228, P. R. China
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Huan Wang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan 570228, P. R. China
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200438, P. R. China
| | - Tao Wang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Peiyu Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Huan Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Hongxia Wang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Lars-Anders Hansson
- Department of Biology/Aquatic Ecology, Ecology Building, Lund University, Lund SE-22100, Sweden
| | - Jun Xu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan 570228, P. R. China
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
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Ren X, Wang Y, Zhang K, Ding Y, Zhang W, Wu M, Xiao B, Gu P. Transmission of Microcystins in Natural Systems and Resource Processes: A Review of Potential Risks to Humans Health. Toxins (Basel) 2023; 15:448. [PMID: 37505717 PMCID: PMC10467081 DOI: 10.3390/toxins15070448] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/01/2023] [Accepted: 07/04/2023] [Indexed: 07/29/2023] Open
Abstract
The rapid rise of microcystins (MCs) poses a serious threat to global freshwater ecosystems and has become an important issue of global public health. MCs have considerable stability and are the most widely distributed hepatotoxins. It cannot only accumulate in aquatic organisms and transfer to higher nutrients and levels, but also be degraded or transferred during the resource utilization of cyanobacteria. No matter which enrichment method, it will lead to the risk of human exposure. This review summarizes the research status of MCs, and introduces the distribution of MCs in different components of aquatic ecosystems. The distribution of MCs in different aquatic organisms was summarized, and the potential risks of MCs in the environment to human safety were summarized. MCs have polluted all areas of aquatic ecosystems. In order to protect human life from the health threats caused by MCs, this paper also proposes some future research directions to promote MCs control and reduce human exposure to MCs.
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Affiliation(s)
| | | | | | | | | | | | | | - Peng Gu
- School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; (X.R.); (Y.W.); (K.Z.); (Y.D.); (W.Z.); (M.W.); (B.X.)
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