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Metagenomics reveals the microbial community and functional metabolism variation in the partial nitritation-anammox process:From collapse to recovery

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Journal of Environmental Sciences 2024年第1期135卷 210-221页

作者： hong Wang Hui Gong Xiaohu dai Min Yang State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China BIOMATH Department of Data Analysis and Mathematical ModellingGhent UniversityGhent 9000Belgium

Mainstream partial nitritation-anammox(PNA)process easily suffers from performance instability and even reactor collapse in application.Thus,it is of great significance to unveil the characteristic of performance recovery,understand the intrinsic mechanism and then propose operational strategy.In this study,we combined long-term reactor operation,batch tests,and metagenomics to reveal the succession of microbial community and functional metabolism variation from system collapse to recovery.Proper aeration control(0.10-0.25mg O_(2)/L)was critical for performance recovery.It was also found that Candidatus Brocadia became the dominant flora and its abundance increased from 3.5%to 11.0%.Significant enhancements in carbon metabolism and phospholipid biosynthesis were observed during system recovery,and the genes abundance related to signal transduction was dramatically increased.The up-regulation of sdh and suc genes showed the processes of succinate dehydrogenation and succinyl-CoA synthesis might stimulate the production of amino acids and the synthesis of proteins,thereby possibly improving the activity and abundance of AnAOB,which was conducive to the performance recovery.Moreover,the increase in abundance of hzs and hdh genes suggested the enhancement of the anammox process.Changes in the abundance of key genes involved in nitrogen metabolism indicated that nitrogen removal pathway was more diverse after system recovery.The achievement of performance recovery was driven by anammox,nitrification and denitrification coupled with dissimilatory nitrate reduction to ammonium.These results provide deeper insights into the recovery mechanism of PNA system and also provide a potential regulation strategy for the stable operation of the mainstream PNA process.

关键词： Partial nitritation-anammox Metagenomics Microbial community Functional metabolism Recovery

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Grain refinement of 5A06 aluminum alloy welds caused by tungsten inert gas welding arc characteristics under Ar-He alternating gas supply conditions:a coupled method of water-cooled copper plate test/numerical simulation

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Journal of Iron and Steel Research(International) 2024年第3期31卷 767-777页

作者： hong-bin dai Jian Miao Jia-xin Lin School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040HeilongjiangChina

The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and states.In the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change characteristics.The FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were obtained.Combined with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas supply.This unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.

关键词： Alternating gas supply Grain refinement Numerical simulation Tungsten argon arc morphology Microstructure Mechanical property

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Fecal microbiota transplantation for irritable bowel syndrome:Current evidence and perspectives

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World Journal of Gastroenterology 2024年第16期30卷 2179-2183页

作者： Cong dai Yu-hong Huang Min Jiang Department of Gastroenterology First Hospital of China Medical UniversityShenyang 110001Liaoning ProvinceChina

In this editorial we comment on the article published in the recent issue of the World journal of Gastroenterology.We focus specifically on the mechanisms underlying the effects of fecal microbiota transplantation(FMT)for irritable bowel syndrome(IBS),the factors which affect the outcomes of FMT in IBS patients,and challenges.FMT has emerged as a efficacious intervention for clostridium difficile infection and holds promise as a therapeutic modality for IBS.The utilization of FMT in the treatment of IBS has undergone scrutiny in numerous randomized controlled trials,yielding divergent outcomes.The current frontier in this field seeks to elucidate these variations,underscore the existing knowledge gaps that necessitate exploration,and provide a guideline for successful FMT implementation in IBS patients.At the same time,the application of FMT as a treatment for IBS confronts several challenges.

关键词： Fecal microbiota transplantation Irritable bowel syndrome Microbiota Randomized controlled trial Meta-analysis

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Antiviral treatment standards for hepatitis B:An urgent need for expansion

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World Journal of Gastroenterology 2024年第4期30卷 418-420页

作者： Zi-hong Bao Zhi-Kun dai Hao-Xian Tang Department of Infectious Diseases The First Affiliated Hospital of Shantou University Medical CollegeShantou 515041Guangdong ProvinceChina Medical College Shantou University Medical CollegeShantou 515041Guangdong ProvinceChina Department of Cardiology The First Affiliated Hospital of Shantou University Medical CollegeShantou 515041Guangdong ProvinceChina

The present letter to the editor is related to the review with the title“Past,present,and future of long-term treatment for hepatitis B virus.”Chronic hepatitis B(CHB)represents an important and pressing public health concern.Timely identification and effective antiviral therapy hold the potential to reduce liver-related mortality attributable to chronic infection with hepatitis B virus(HBV)substantially.However,the current global treatment rates for CHB remain conspicuously low,with the excessively stringent treatment criteria advocated by national CHB guidelines being a contributing factor to these low rates.Nevertheless,recent strides in comprehending this malady and the emergence of novel antiviral agents prompt the imperative re-evaluation of treatment standards to extend the sphere of potential beneficiaries.An impending need arises for a novel paradigm for the classification of patients with CHB,the expansion of antiviral treatment eligibility for HBV-infected individuals,and even the streamlining of the diagnostic process for CHB to amplify cost-effectiveness and augment survival prospects.

关键词： Hepatitis B virus Chronic hepatitis B Antiviral treatment criteria Serum alanine aminotransferase Liver-related mortality Letter to the Editor

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Enhancing cut selection through reinforcement learning

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Science China Mathematics 2024年第6期67卷 1377-1394页

作者： Shengchao Wang Liang Chen Lingfeng Niu Yu-hong dai Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing100190China Research Center on Fictitious Economy and Data Science Chinese Academy of SciencesBeijing100190China

With the rapid development of artificial intelligence in recent years,applying various learning techniques to solve mixed-integer linear programming(MILP)problems has emerged as a burgeoning research domain.Apart from constructing end-to-end models directly,integrating learning approaches with some modules in the traditional methods for solving MILPs is also a promising direction.The cutting plane method is one of the fundamental algorithms used in modern MILP solvers,and the selection of appropriate cuts from the candidate cuts subset is crucial for enhancing efficiency.Due to the reliance on expert knowledge and problem-specific heuristics,classical cut selection methods are not always transferable and often limit the scalability and generalizability of the cutting plane method.To provide a more efficient and generalizable strategy,we propose a reinforcement learning(RL)framework to enhance cut selection in the solving process of MILPs.Firstly,we design feature vectors to incorporate the inherent properties of MILP and computational information from the solver and represent MILP instances as bipartite graphs.Secondly,we choose the weighted metrics to approximate the proximity of feasible solutions to the convex hull and utilize the learning method to determine the weights assigned to each metric.Thirdly,a graph convolutional neural network is adopted with a self-attention mechanism to predict the value of weighting factors.Finally,we transform the cut selection process into a Markov decision process and utilize RL method to train the model.Extensive experiments are conducted based on a leading open-source MILP solver SCIP.Results on both general and specific datasets validate the effectiveness and efficiency of our proposed approach.

关键词： reinforcement learning mixed-integer linear programming cutting plane method cut selection

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Electronic regulation to achieve efficient anaerobic digestion of organic fraction of municipal solid waste(OFMSW):strategies,challenges and potential solutions

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 159-165页

作者： Yongdong Chen hong Wang Parisa Ghofrani-Isfahani Li Gu Xiaoguang Liu Xiaohu dai State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Tongji UniversityShanghai 200092China Department of Chemical and Biochemical Engineering Technical University of DenmarkKgs Lyngby DK-2800Denmark College of Environment and Ecology Chongqing UniversityChongqing 400045China

Anaerobic digestion(AD)of organic fraction of municipal solid waste(OFMSW)is prone to system breakdown under high organic loading rates(OLRs)condition,which subsequently reduces the efficiency of digestion process and results in substantial economic losses.In this perspective paper,the substances metabolisms,electrons flow,as well as microbial interaction mechanisms within AD process are comprehensively discussed,and the underlying bottleneck that causes inefficient methane production is identified,which is“electrons surplus”.Systems encountering severe electron surplus are at risk of process failure,making it crucial to proactively prevent this phenomenon through appropriate approaches.On this basis,the present perspective proposes three potential electronic regulation strategies to prevent electrons surplus,namely,electron shunt,accelerating electron transfer and regulating methanogenic metabolism pathway,and presents specific methodologies for each strategy.Furthermore,the potential solutions to challenges that may occur during the electronic regulation process are also presented in this paper.This perspective aims to provide innovative approaches to achieve the efficient and stable operation of OFMSW anaerobic digestion,especially under high OLRs condition.

关键词： Anaerobic digestion Electrons surplus Electronic regulation Electrons shunt Electron transfer Methanogenic metabolism pathway

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Nrf2-mediated ferroptosis of spermatogenic cells involved in male reproductive toxicity induced by polystyrene nanoplastics in mice

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第4期25卷 307-323页

作者： Xufeng FU Hang HAN hong YANG Bo XU Wenjie dai Ling LIU Tiantian HE Xing DU Xiuying PEI Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education School of Basic Medical SciencesNingxia Medical UniversityYinchuan 750004China Key Laboratory of Reproduction and Genetics in Ningxia Ningxia Medical UniversityYinchuan 750004China

Microplastics(MPs)and nanoplastics(NPs)have become hazardous materials due to the massive amount of plastic waste and disposable masks,but their specific health effects remain uncertain.In this study,fluorescence-labeled polystyrene NPs(PS-NPs)were injected into the circulatory systems of mice to determine the distribution and potential toxic effects of NPs in vivo.Interestingly,whole-body imaging found that PS-NPs accumulated in the testes of mice.Therefore,the toxic effects of PS-NPs on the reproduction systems and the spermatocytes cell line of male mice,and their mechanisms,were investigated.After oral exposure to PS-NPs,their spermatogenesis was affected and the spermatogenic cells were damaged.The spermatocyte cell line GC-2 was exposed to PS-NPs and analyzed using RNA sequencing(RNA-seq)to determine the toxic mechanisms;a ferroptosis pathway was found after PS-NP exposure.The phenomena and indicators of ferroptosis were then determined and verified by ferroptosis inhibitor ferrostatin-1(Fer-1),and it was also found that nuclear factor erythroid 2-related factor 2(Nrf2)played an important role in spermatogenic cell ferroptosis induced by PS-NPs.Finally,it was confirmed in vivo that this mechanism of Nrf2 played a protective role in PS-NPs-induced male reproductive toxicity.This study demonstrated that PS-NPs induce male reproductive dysfunction in mice by causing spermatogenic cell ferroptosis dependent on Nrf2.

关键词： Polvstyrene nanoplastics(PS-NPs) Reproductive toxicity Ferroptosis Nuclear factor ervthroid 2-related factor 2(Nrf2)

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A 16-bit 18-MSPS flash-assisted SAR ADC with hybrid synchronous and asynchronous control logic

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Journal of Semiconductors 2024年第6期45卷 3-12页

作者： Junyao Ji Xinao Ji Ziyu Zhou Zhichao dai Xuhui Chen Jie Zhang Zheng Jiang hong Zhang School of Microelectronics Xi'an Jiaotong UniversityXi'an 710049China Qingdao Hi-image Tech.Co.Ltd. Qingdao 266100China

This paper presents a 16-bit,18-MSPS(million samples per second)flash-assisted successive-approximation-register(SAR)analog-to-digital converter(ADC)utilizing hybrid synchronous and asynchronous(HYSAS)timing control logic based on an on-chip delay-locked loop(DLL).The HYSAS scheme can provide a longer settling time for the capacitive digital-to-analog converter(CDAC)than the synchronous and asynchronous SAR ADC.Therefore,the issue of incomplete settling or ringing in the DAC voltage for cases of either on-chip or off-chip reference voltage can be solved to a large extent.In addition,the fore-ground calibration of the CDAC’s mismatch is performed with a finite-impulse-response bandpass filter(FIR-BPF)based least-mean-square(LMS)algorithm in an off-chip FPGA(field programmable gate array).Fabricated in 40-nm CMOS process,the proto-type ADC achieves 94.02-dB spurious-free dynamic range(SFDR),and 75.98-dB signal-to-noise-and-distortion ratio(SNDR)for a 2.88-MHz input under 18-MSPS sampling rate.

关键词： SAR ADC control logic reference ringing DAC incomplete settling

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Interfacial reaction between AZ91D magnesium alloy melt and mild steel under high temperature

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China Foundry 2024年第2期21卷 159-167页

作者： Jia-hong dai Jian-yue Zhang Bin Jiang Xiang-jun Xu Zhong-tao Jiang hong-mei Xie Qing-shan Yang Guo-qing Zhang College of Materials Science and Engineering Yangtze Normal UniversityChongqing 408100China National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Jiulongyuan High-tech Industry Group Co. Ltd.Chongqing 400080China Loncin Industry Co. Ltd.Chongqing 400080China Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA Chongqing Key Laboratory of Materials Surface&Interface Science Chongqing University of Arts and SciencesChongqing 402160China School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China

The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting process.Therefore,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is necessary.In the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild steel.Meanwhile,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and AZ91D.AlFe_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg matrix.It is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction process.By measuring the thickness of different layers,the growth constant was calculated.It increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.

关键词： AZ91D mild steel interface reaction intermetallic growth kinetics

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Efficient electroreduction of nitrate via enriched active phases on copper-cobalt oxides

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Chinese Chemical Letters 2024年第4期35卷 204-209页

作者： Ling Fang Sha Wang Shun Lu Fengjun Yin Yujie dai Lin Chang hong Liu Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China University of Chinese Academy of Sciences Beijing 100049China

Electrochemical conversion of nitrate(NO_(3)~-) to ammonia(NH_(3)) can target two birds with one stone well, in NO_(3)^(-)-containing sewage remediation and sustainable NH_(3) production. However, single metalbased catalysts are difficult to drive high-efficient NO_(3)~- removal due to the multi-electron transfer steps.Herein, we present a tandem catalyst with simple structure, Cu-Co binary metal oxides(Cu-Co-O), by engineering intermediate phases as catalytic active species for NO_(3)~- conversion. Electrochemical evaluation,X-ray photoelectron spectroscopy, and in situ Raman spectra together suggest that the newly-generated Cu-based phases was prone to NO_(3)~- to NO_(2)~- conversion, then NO_(2)~- was reduced to NH_(3) on Co-based species. At an applied potential of -1.1 V vs. saturated calomel electrode, the Cu-Co-O catalyst achieved NO_(3)~- -N removal of 90% and NH_(3) faradaic efficiency of 81% for 120 min in 100 m L of 50 mg/L NO_(3)~- -N,consuming only 0.69 k Wh/mol in a two-electrode system. This study provides a facile and efficient engineering strategy for developing high-performance catalysts for electrocatalytic nitrate conversion.

关键词： NO_(3)^(-)-containing sewage remediation Electrocatalytic reduction Copper-cobalt oxides Tandem reactivity Enriched active phases

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