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Characteristics and distribution of phosphorus in surface sediments of a shallow lake

Journal of Environmental Sciences 2023年第2期124卷 50-60页

作者： Ziwei long Zehua ji Yuansheng Pei State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China The Key Laboratory of Water and Sediment Sciences Ministry of EducationSchool of EnvironmentBeijing Normal UniversityBeijing 100875China

Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake environment.The mobility and bioavailability of P primarily depend on the contents of different P forms,which in turn depend on the sedimentary environment.Here,sediment samples from Baiyangdian(BYD)lake were collected and measured by the Standards,Measurements,and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy(31P NMR)to characterize different P forms and their relationships with sediment physicochemical properties.The P content in the sediments varied in different areas and had characteristics indicative of exogenous river input.Inorganic P(334–916 mg/kg)was the dominant form of P.The 31P NMR results demonstrated that orthophosphate monoesters(16–110 mg/kg),which may be a source of P when redox conditions change,was the dominant form of organic P(20–305 mg/kg).The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities,and the regions affected by exogenous river input had a higher content of P and a higher risk of P release.Principal component analysis indicated that P bound to Fe,Al,and Mn oxides and hydroxides(NaOH-P)and organic P were mainly derived from industrial and agricultural pollution,respectively.Redundancy analysis indicated that increases in pH lead to the release of NaOH-P.Organic matter plays an important role in the organic P biogeochemical cycle,as it acts as a sink and source of organic P.

关键词： Sediment Phosphorus forms SMT 31P NMR

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Numerical investigation of the influence of vortex generator on propeller cavitation and hull pressure fluctuation by DDES

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Journal of Hydrodynamics 2022年第3期34卷 444-450页

作者： Yun long Han-qiao Han Bin ji Xin-ping long Wuhan Second Ship Design and Research Institute Wuhan430064China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China School of Power and Mechanical Engineering Wuhan UniversityWuhan430072China

In this study,the delayed detached eddy simulation(DDES)is coupled with a homogenous cavitation model to simulate the cavitating turbulent flow around a propeller behind a full body ship with special emphasis on the influence of the vortex generator(VG)on the propeller cavitation and the hull pressure fluctuation.The small calculation uncertainty as evaluated by the DDES verification and validation(V&V)method indicates that the present simulation can accurately reproduce the propeller performance and cavitation,and the predicted hull pressure fluctuation is in a fairly good agreement with the available experimental data.The mechanism is explored through the current numerical results how the VG affects the local velocity distribution,along with the influences of the VG on the propeller cavitation and the hull pressure fluctuation.It is shown that the streamwise vortex is induced by the VG near the hull boundary layer.The very low velocity region in the hull wake is reduced due to the effect of the streamwise vortex.Besides,the propeller cavitation develops more mildly and the hull pressure fluctuation decreases due to the influence of the VG.

关键词： Propeller cavitation delayed detached eddy simulation(DDES) vortex generator(VG) streamwise vortex

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LES investigation of cavitating flows around a sphere with special emphasis on the cavitation–vortex interactions

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Acta Mechanica Sinica 2020年第6期36卷 1238-1257,I0002页

作者： Yun long Xinping long Bin ji State Key Lab of Water Resources and Hydropower Engineering Science School of Power and Mechanical EngineeringWuhan UniversityWuhan430072China Key Lab of Jet Theory and New Technology of Hubei Province Wuhan UniversityWuhan430072China

Large eddy simulation(LES)was coupled with a homogeneous cavitation model to study turbulent cavitating flows around a sphere.The simulations are in good agreement with available experimental data and the simulated accuracy has been evaluated using the LES verification and validation method.Various cavitation numbers are simulated to study important flow characteristics in the sphere wake,e.***.periodic cavity growth/contraction,interactions between the cloud and sheet cavitations and the vortex structure evolution.The spectral characteristics of the wake for typical cloud cavitation conditions were classified as the periodic cavitation mode,high Strouhal number mode and low Strouhal number mode.Main frequency distributions in the wake were analyzed and different dominant flow structures were identified for each of the three modes.Further,the cavitation and vortex relationship was also studied,which is an important issue associated with complex cavitating sphere wakes.Three types of cavitating vortex structures alternate,which indicates that three different cavity shedding regimes may exist in the wake.Analysis of vorticity transport equation shows a significant vorticity increase at the cavitation closure region and in the vortex cavitation region.This study provides a physical perspective to further understand the flow mechanisms in cavitating sphere wakes.

关键词： Cavitation Cavitating flow Sphere Large eddy simulation(LES) Vortex structure

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Neurodevelopmental defects as a primer of neurodegeneration:lessons from spinal muscular atrophy and Huntington's disease

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Neural Regeneration Research 2023年第9期18卷 1952-1953页

作者： Stuart J.Grice ji-long Liu Medical Research Council Functional Genomics Unit Department of PhysiologyAnatomy and GeneticsUniversity of OxfordOxfordUK School of Life Science and Technology ShanghaiTech UniversityShanghaiChina

Developmental motifs in neurodegeneration:Neurodegeneration,the prominent feature of neurodegenerative disease,is characterized by the progressive and selective loss of neuronal function.As some of the pathologies caused by neurodegeneration may be irreversible,early intervention will be required for the treatments that aim to slow or halt the manifestation of these diseases.Traditionally,neurodegeneration evokes the idea of a progressive decline of brain function.

关键词： neurodegeneration Huntington function

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VALORIZATION OF BIOGAS THROUGH SIMULTANEOUS CO_(2) AND H_(2)S REMOVAL BY RENEWABLE AQUEOUS AMMONIA SOLUTION IN MEMBRANE CONTACTOR

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Frontiers of Agricultural Science and Engineering 2023年第3期10卷 468-478页

作者： Tao SUN Wenlong LI jiandong WEI Long Ji Qingyao HE Shuiping YAN College of Engineering Huazhong Agricultural UniversityWuhan 430070China Technology&Equipment Center for Carbon Neutrality in Agriculture Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River Ministry of Agriculture and Rural AffairsWuhan 430070China

Upgrading biogas into biomethane not only improves the biogas utilization as vehicle fuel or natural gas substitute,but also reduces the greenhouse gases emissions.Considering the principle of engineering green energy process,the renewable aqueous ammonia(RAA)solution obtained from biogas slurry was used to remove H_(2)S and CO_(2) simultaneously in the hollow fiber membrane contactor.RAA was mimicked in this study using the ammonia aqueous solution mixed with some typical impurities including ethanol,acetic acid,propionic acid,butyric acid and NH4HCO_(3).Compared with the typical physical absorption(i.e.,pure water)removing 48%of H_(2)S from biogas,RAA with 0.1 mol·L^(−1) NH_(3) could remove 97%of H_(2)S.Increasing the NH3 concentration from 0.1 to 0.5 mol·L^(−1) could elevate the CO_(2) absorption flux from 0.97 to 1.72 mol·m^(−2)·h^(−1) by 77.3%.Among the impurities contained in RAA,ethanol has a less impact on CO_(2) absorption,while other impurities like CO_(2) and acetic acid have significant negative impacts on CO_(2) absorption.Fortunately,the impurities have a less influence on H_(2)S removal efficiency,with more than 98%of H_(2)S could be removed by RAA.Also,the influences of operating parameters on acid gases removal were investigated to provide some engineering suggestions.

关键词： biomethane biogas purification CO_(2)removal H_(2)S removal membrane absorption

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mTOR-S6K1 pathway mediates cytoophidium assembly

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Journal of Genetics and Genomics 2019年第2期46卷 65-74页

作者： Zhe Sun ji-long Liu School of Life Science and Technology ShanghaiTech University MRC Functional Genomics Unit Department of Physiology Anatomy and Genetics University of Oxford

CTP synthase(CTPS), the rate-limiting enzyme in de novo CTP biosynthesis, has been demonstrated to assemble into evolutionarily conserved filamentous structures, termed cytoophidia, in Drosophila, bacteria, yeast and mammalian cells. However, the regulation and function of the cytoophidium remain elusive. Here, we provide evidence that the mechanistic target of rapamycin(mTOR) pathway controls cytoophidium assembly in mammalian and Drosophila cells. In mammalian cells, we find that inhibition of mTOR pathway attenuates cytoophidium formation. Moreover, CTPS cytoophidium assembly appears to be dependent on the mTOR complex 1(mTORC1) mainly. In addition, knockdown of the mTORC1 downstream target S6 K1 can inhibit cytoophidium formation, while overexpression of the constitutively active S6 K1 reverses mTOR knockdown-induced cytoophidium disassembly. Finally, reducing m TOR protein expression results in a decrease of the length of cytoophidium in Drosophila follicle cells.Therefore, our study connects CTPS cytoophidium formation with the mTOR signaling pathway.

关键词： mTOR Cytoophidium CTP synthase Colorectal cancer cell Drosophila

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Temperature-sensitive cytoophidium assembly in Schizosaccharomyces pombe

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Journal of Genetics and Genomics 2019年第9期46卷 423-432页

作者： jing Zhang ji-long Liu MRC Functional Genomics Unit Department of PhysiologyAnatomy and GeneticsUniversity of OxfordOxford0X13PTUnited Kingdom School of Life Science and Technology ShanghaiTech UniversityShanghai201210China

The metabolic enzyme CTP synthase(CTPS) is able to compartmentalize into filaments,termed cytoophidia,in a variety of organisms including bacteria,budding yeast,fission yeast,fruit flies and mammals.A previous study in budding yeast shows that the filament-forming process of CTPS is not sensitive to temperature shift.Here we study CTPS filamentation in the fission yeast Schizosaccharomyces pombe.To our surprise,we find that both the length and the occurrence of cytoophidia in S.pombe decrease upon cold shock or heat shock.The temperature-dependent changes of cytoophidia are fast and reversible.Taking advantage of yeast genetics,we demonstrate that heat-shock proteins are required for cytoophidium assembly in S.pombe.Temperature sensitivity of cytoophidia makes S.pombe an attractive model system for future investigations of this novel membraneless organelle.

关键词： CTP synthase Cytoophidium Schizosaccharomyces pombe Heat-shock protein Nucleoside/nucleotide metabolism Cell biology Yeast genetics Cell compartmentalization

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Carbon and Nitrogen Footprints of Major Cereal Crop Production in China:A Study Based on Farm Management Surveys

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Rice science 2022年第3期29卷 288-298页

作者： XU Chunchun CHEN Zhongdu ji long LU jianfei College of Agriculture Yangzhou UniversityYangzhou 225009China China National Rice Research Institute Hangzhou 310006China

Greenhouse gas(GHG)emissions and reactive nitrogen(Nr)releases are central environmental problems,which are closely linked to climate change,environmental ecology and crop production.Sustainable development of agriculture plays an important role in GHG emissions and Nr loss.The life cycle assessment(LCA)method was used to calculate the product and farm carbon footprints(CFs)and nitrogen footprints(NFs)in rice,wheat and maize production in China based on farm survey data.The results pinpointed that the CFs of rice,wheat and maize were 0.87,0.30 and 0.24 kg/kg.Meanwhile,the computed NFs were 17.11,14.26 and 6.83 g/kg,respectively.Synthetic nitrogen fertilizer applications and methane(CH4)emissions were dominant CF sources,while ammonia(NH3)volatilization was the main NF contributor.Moreover,significant decreases in CF and NF by 20%–54%and 33%–61%,respectively,were found in large-size farms(>20 hm^(2))when compared to small-size farms(<0.7 hm^(2)).Furthermore,the significantly positive relationships between CF and NF indicated the potential for simultaneous mitigation in the regions with high agricultural inputs,like amounts of fertilizer.Based on our results,some effective solutions would be favorable toward mitigating climate change and eutrophication of the major cereal crop production in China,especially optimizing fertilizer use and farm machinery operation efficiencies,as well as developing large-size farms with intensive farming.

关键词： carbon footprint nitrogen footprint life cycle assessment grain crop sustainability

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Differential Operator Approach to■quantum Groups and Their Oscillator Representations

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1360-1374页

作者： Zhao Bing FAN ji Cheng GENG Shao long HAN College of Mathematical Science Harbin Engineering UniversityHarbin 150001P.R.China

For a quasi-split Satake diagram,we define a modified q-Weyl algebra,and show that there is an algebra homomorphism between it and the corresponding■quantum group.In other words,we provide a differential operator approach to■quantum groups.Meanwhile,the oscillator representations of■quantum groups are obtained.The crystal basis of the irreducible subrepresentations of these oscillator representations are constructed.

关键词： ■quantum group differential operator oscillator representation crystal basis

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A Numerical Study on the Responses of Wave-Driven Circulation to Varying Incident Wave Forcing and Reef Morphology in A Reef-Lagoon-Channel System

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China Ocean Engineering 2022年第6期36卷 933-946页

作者： YAO Yu WU ji LI jiang-xia CHEN long School of Hydraulic and Environmental Engineering Changsha University of Science and TechnologyChangsha 410114China Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province Changsha 410114China

Wave-driven circulation in a reef-lagoon-channel system has significant ecological,geomorphological,and environmental implications.However,there is still research gap in fully understanding the responses of wave-driven circulation in the system to varying incident wave forcing and reef morphology.To better interpret the wave-current process inside an idealized reef-lagoon-channel configuration,a numerical model based on the horizontally two-dimensional(2DH)fully nonlinear Boussinesq equations is presented in this study.The adopted model is firstly validated by a published laboratory dataset for wave height,wave setup and mean current in the system.Subsequently,the impacts of wave forcing(incident wave height,incident wave period,reef-flat wave level)and reef morphological(fore-reef slope,cross-shore reef-flat width,channel width,reef roughness)factors that are not fully considered in the previous laboratory studies are reported through the numerical simulations in this study.Finally,the model is applied to analyze the wave pump efficiency parameter in the system,and an empirical equation to predict this parameter is also proposed.

关键词： wave-induced setup circulation cell coral reef wave pump efficiency Boussinesq equations

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