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Effects of combustion temperature on the optical properties of brown carbon from biomass burning

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Journal of Environmental Sciences 2024年第3期137卷 302-309页

作者： Peng Gao Rule Deng Song Jia Yue li Xuefei Wang qian Xing School of Chemistry Sciences University of Chinese Academy of SciencesBeijing 100049China College of Chemistry and Materials Engineering Beijing Technology and Business UniversityBeijing 100048China

Biomass burning has been known as one of main sources of Brown Carbon(BrC)in atmosphere.In this study,by controlling the combustion temperature at 250℃,350℃,and 450℃,the methanol soluble organic carbon(MSOC)and methanol insoluble carbon(MISC)from pine wood burning was collected by impinger.UV–Vis,excitation emission matrix(EEM),TEM and FTIR spectra were applied to investigate the properties of BrC collected.For MSOC at 250℃ and 350℃,all the spectral profiles of UV–Vis absorption and excitation emission matrix are almost the same,while the EEM of MSOC at 450℃ are different from that of the other two.For MISC fuorescence was observed only in the case of 450℃.In the FTIR spectra,with the temperature increasing the peaks associated to the oxygen-contained functions was weakened,indicating the formation of the fuorophores with larger conjugated system,especially aromatic hydrocarbons.Our results show that biomass combustion at low temperature produces more oxygen-riched BrC,which possesses relatively lower light absorption,while at high temperature produces more aromatics hydrocarbons with relatively strong light absorption.The results of this work are helpful to trace the source of brown carbon and optimize biomass energy utilization.

关键词： Biomass burning Combustion temperature Methanol-soluble brown carbon EEM Impinger

Optimization of Band Gap of 1D Elastic Metamaterial Under Impact Load by Regulating Stiffness

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Acta Mechanica Solida Sinica 2024年第1期37卷 148-154页

作者： Tong li Xianlong jin Yongqiang li Peizhong Yang School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Mechanical System and Vibration Shanghai Jiaotong UniversityShanghai 200240China College of Science Northeastern UniversityShenyang 110819China

Designing materials that mitigate impacts effectively are crucial for protecting people and structures.Here,a single-resonator metamaterial with negative mass characteristics is proposed for impact mitigation,and numerical analysis of wave propagation shows explicitly how the spring stiffness and number of unit cells influence that mitigation.The results show clearly that a metamaterial with differing microstructural stiffness is better at mitigating the effect of a shock wave than one with a unique stiffness.Also,there is a critical number of unit cells beyond which the shock wave is not attenuated further,but the fabrication complexity increases.In the 40 groups of microstructural regions in this example,the attenuation effect no longer increases when there are more than 35 groups.This work offers guidance for microstructure designs in metamaterials and provides new ideas for using metamaterials to mitigate shock waves.

关键词： Elastic metamaterials Wave attenuation Stiffness Number of unit cells

Development of RPA-Cas12a-fluorescence assay for rapid and reliable detection of human bocavirus 1

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Animal Models and Experimental Medicine 2024年第2期7卷 179-188页

作者： Weidong qian Xuefei Wang Ting Wang Jie Huang qian Zhang Yongdong li Si Chen School of Food and Biological Engineering Shaanxi University of Science and TechnologyXi'anP.R.China Department of Dermatology Huazhong University of Science and Technology Union Shenzhen HospitalShenzhenP.R.China Ningbo Municipal Center for Disease Control and Prevention NingboP.R.China Medical College of Shenzhen University ShenzhenP.R.China

Human bocavirus(HBoV)1 is considered an important pathogen that mainly affects infants aged 6–24 months,but preventing viral transmission in resource-limited regions through rapid and affordable on-site diagnosis of individuals with early infection of HBoV1 remains somewhat challenging.Herein,we present a novel faster,lower cost,reliable method for the detection of HBoV1,which integrates a recombinase polymerase amplification(RPA)assay with the CRISPR/Cas12a system,designated the RPA-Cas12a-fluorescence assay.The RPA-Cas12a-fluorescence system can specifically detect target gene levels as low as 0.5 copies of HBoV1 plasmid DNA per microliter within 40 min at 37℃without the need for sophisticated instruments.The method also demonstrates excellent specificity without cross-reactivity to non-target pathogens.Furthermore,the method was appraised using 28 clinical samples,and displayed high accuracy with positive and negative predictive agreement of 90.9%and 100%,respectively.Therefore,our proposed rapid and sensitive HBoV1 detection method,the RPA-Cas12a-fluorescence assay,shows promising potential for early on-site diagnosis of HBoV1 infection in the fields of public health and health care.The established RPA-Cas12a-fluorescence assay is rapid and reliable method for human bocavirus 1 detection.The RPA-Cas12a-fluorescence assay can be completed within 40 min with robust specificity and sensitivity of 0.5 copies/μl.

关键词： CRISPR-Cas12a detection human bocavirus 1 on-site diagnosis recombinase polymerase amplification

Transplantation of fibrin-thrombin encapsulated human induced neural stem cells promotes functional recovery of spinal cord injury rats through modulation of the microenvironment

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Neural Regeneration Research 2024年第2期19卷 440-446页

作者： Sumei liu Baoguo liu qian li Tianqi Zheng Bochao liu Mo li Zhiguo Chen Cell Therapy Center Beijing Institute of GeriatricsXuanwu HospitalCapital Medical UniversityNational Clinical Research Center for Geriatric Diseasesand Key Laboratory of Neurodegenerative DiseasesMinistry of EducationBeijingChina Center of Neural Injury and Repair Beijing Institute for Brain DisordersBeijingChina Center of Parkinson’s Disease Beijing Institute for Brain DisordersBeijingChina

Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.

关键词： biomaterial fibrinogen functional recovery induced neural stem cell transplantation microenvironment microglia spinal cord injury thrombin

In vivo imaging reveals a synchronized correlation among neurotransmitter dynamics during propofol and sevoflurane anesthesia

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Zoological Research 2024年第3期45卷 679-690页

作者： Gao-lin Qiu li-Jun Peng Peng Wang Zhi-Lai Yang Ji-qian Zhang Hu liu Xiao-Na Zhu jin Rao Xue-Sheng liu Department of Anesthesiology First Affiliated Hospital of Anhui Medical UniversityHefeiAnhui 230022China School of life Science and Technology ShanghaiTech UniversityShanghai 201210China

General anesthesia is widely applied in clinical practice.However,the precise mechanism of loss of consciousness induced by general anesthetics remains unknown.Here,we measured the dynamics of five neurotransmitters,includingγ-aminobutyric acid,glutamate,norepinephrine,acetylcholine,and dopamine,in the medial prefrontal cortex and primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from a neurotransmitter perspective.Results revealed that the concentrations of γ-aminobutyric acid,glutamate,norepinephrine,and acetylcholine increased in the cortex during propofol-induced loss of consciousness.Dopamine levels did not change following the hypnotic dose of propofol but increased significantly following surgical doses of propofol anesthesia.Notably,the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness.Furthermore,the neurotransmitter dynamic networks were not synchronized in the non-anesthesia groups but were highly synchronized in the anesthetic groups.These findings suggest that neurotransmitter dynamic network synchronization may cause anesthetic-induced loss of consciousness.

关键词： General anesthesia Loss of consciousness In vivo neurotransmitter imaging Medial prefrontal cortex Primary visual cortex

S-scheme heterojunction in photocatalytic hydrogen production

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Journal of Materials Science & Technology 2024年第2期169卷 82-104页

作者： Teng li Noritatsu Tsubaki Zhiliang jin School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan 750021China Department of Applied Chemistry Graduate School of EngineeringUniversity of ToyamaGofuku 3190Toyama 930-8555Japan

As an ideal secondary energy source,hydrogen has the title of clean energy and the product of its complete combustion is only water,which is not polluting to the environment.Photocatalytic hydrogen production technology is an environmentally friendly,safe,and low-cost strategy that requires only an inexhaustible amount of solar energy and water as feedstock.This paper provides a detailed and detailed review of S-scheme heterojunction photocatalysts for photocatalytic hydrogen production,mainly including TiO_(2)-based,Perovskite-based,CdS-based,Graphitic phase carbon nitride-based,COF-based graphdiyne-based,ZnO-based,and ZnIn_(2)S_(4)-based S-scheme heterojunction photocatalysts.The classification of S-scheme heterojunctions is summarized.What’s more,various characterizations for direct verification of the charge migration mechanism of S-scheme heterojunctions are outlined.Based on the present study,the future potential challenges and future research trends for S-scheme heterojunctions in photocatalytic hydrogen evolution technology are pointed out,which provides feasible strategies for the development and design of S-scheme heterojunction photocatalysts in the field of photocatalytic hydrogen evolution.

关键词： S-scheme heterojunction Photocatalysis Charges migration Hydrogen evolution

Carbon emission quantification and reduction in pavement use phase:A review

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第1期11卷 69-91页

作者： linjie Zhu jin li Feipeng Xiao Key Laboratory of Road and Traffic Engineering of Ministry of Education Tongji UniversityShanghai 201804China

The carbon emissions arising from road pavement infrastructures have emerged as critical issue in recent years.The life cycle of a pavement can be divided into five phases,namely raw materials and production,construction,use,maintenance and end of life.While the use phase generates the highest carbon emissions throughout the pavement's life cycle,it is usually neglected in most pavement life cycle assessment(LCA)studies due to its complexity and uncertainty.Therefore,this review selected 126 relevant references,focuses on quantification methods,influential factors and reduction technologies of carbon emissions in pavement use phase.Among the carbon accounting approached,the LCA approach,remains the most widely used for evaluating the environmental impact of pavements.Second,the primary influential factors on the use phase'carbon emission include pavement-vehicle interaction primarily affected by pavement roughness,pavement albedo and climate change.Most influential factors above indirectly cause changes in carbon emissions by influencing the pavement performance and subsequent vehicle emissions.Finally,the review surveys carbon emission reduction technologies during pavement use phase,focusing mainly on reducing pavement rolling resistance and constructing cool pavements.Reflective pavements and permeable pavements are the most widely used cool pavement technologies.Overall,the aspects involved in this paper hold significant promise for quantifying and reducing carbon emissions in the pavement use phase.

关键词： Pavement Carbon emission life cycle assessment Use phase Emission reduction

Efflcient machining of a complex blisk channel using a disc cutter

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Chinese Journal of Aeronautics 2024年第1期37卷 414-437页

作者： Xiangyu li Zhaoyu li Dong HE Junxue REN qian FENG Kai TANG Department of Mechanical and Aerospace Engineering Hong Kong University of Science and TechnologyHong Kong 999077China Key Laboratory of High Performance Manufacturing for Aero Engine(Northwestern Polytechnical University) Ministry of Industry and Information TechnologyXi’an 710072China Xi’an Sanhang Power Technology Co. LtdXi’an 710000China HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute FutianShenzhen 518057China HKUST Shenzhen Research Institute Shenzhen 518057China

For rough machining of a complex narrow cavity,e.g.,a complex blisk channel on an aero-engine,the typically used cutting tools are the slender cylindrical cutter and conical cutter.Nevertheless,as neither of the two is particularly suited for rough machining,wherein the main purpose is to remove a large volume as quickly as possible,the machining efficiency is low,especially when the part materials are of hard-to-cut types(e.g.,Titanium-alloy)for which it often takes days to rough machine a blisk.Fortunately,disc machining provides a new and efficient roughing solution,since a disc cutter with a large radius enables a much larger cutting speed and thus a larger material removal rate.However,due to the large radius of the disc cutter,its potential collision with narrow and twisted channels becomes a serious concern.In this paper,we propose a novel twophase approach for efficiently machining a complex narrow cavity workpiece using a disc-shaped cutter,i.e.,3+2-axis disc-slotting of the channel by multiple layers(rough machining)+five-axis disc-milling of the freeform channel side surfaces(semi-finish machining).Both simulation and physical cutting experiments are conducted to assess the effectiveness and advantages of the proposed method.The experimental results show that,with respect to a same cusp-height threshold on the channel side surfaces,the total machining time of the tested part by the proposed method is about only 36%of that by the conventional approach of plunging-milling(for roughing)plus milling by a slender cylindrical cutter(for semi-finishing).

关键词： Blisk channel CNC machining Disc cutter Roughing efficiency Tool path planning

Characteristics of the HIV/AIDS Epidemic among People Aged≥50 Years in China during 2018–2021

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Biomedical and Environmental Sciences 2024年第4期37卷 399-405页

作者： HOU Yu Shan jin Yi Chen CAI Chang TANG Hou lin QIN qian qian LYU Fan National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206China

Objective This study aimed to determine the current epidemiological status of PLWHA aged≥50 years in China from 2018 to 2021.It also aimed to recommend targeted interventions for the prevention and treatment of HIV/AIDS in elderly patients.Methods Data on newly reported cases of PLWHA,aged≥50 years in China from 2018 to 2021,were collected using the CRIMS.Trend tests and spatial analyses were also conducted.Results Between 2018 and 2021,237,724 HIV/AIDS cases were reported among patients aged≥50 years in China.The main transmission route was heterosexual transmission(91.24%).Commercial heterosexual transmission(CHC)was the primary mode of transmission among males,while non-marital non-CHC([NMNCHC];60.59%)was the prevalent route in women.The proportion of patients with CHC decreased over time(Z=67.716,P<0.01),while that of patients with NMNCHC increased(Z=153.05,P<0.01).The sex ratio varied among the different modes of infection,and it peaked at 17.65 for CHC.The spatial analysis indicated spatial clustering,and the high-high clustering areas were mainly distributed in the southwestern and central-southern provinces.Conclusion In China,PLWHA,aged≥50 years,were predominantly infected through heterosexual transmission.The primary modes of infection were CHC and NMNCHC.There were variations in the sex ratio among different age groups,infected through various sexual behaviors.HIV/AIDS cases exhibited spatial clustering.Based on these results,the expansion of HIV testing,treatment,and integrated behavioral interventions in high-risk populations is recommended to enhance disease detection in key regions.

关键词： HIV/AIDS Aged≥50 years China