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Non-isothermal kinetics and characteristics of calcium carbide nitridation reaction with calcium-based additives

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 49-61页

作者： Zhihan zhang Mengxiao Yu Xiaoyu zhang Jinli zhang You han School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

The nitridation reaction of calcium carbide and N_(2) at high temperatures is the key step in the production of ***,the challenges faced by this process,such as high energy consumption and poor product quality,are mainly attributed to the lack of profound understanding of the *** study aimed to improve this process by investigating the non-isothermal kinetics and reaction characteristics of calcium carbide nitridation reaction at different heating rates(10,15,20,and 30℃·min^(-1))using thermogravimetric *** kinetic equation for the nitridation reaction of additive-free calcium carbide sample was obtained by combining model-free methods and model-fitting *** effect of different calcium-based additives(CaCl_(2) and CaF_(2))on the reaction was also *** results showed that the calcium-based additives significantly reduced reaction temperature and activation energy E_(a) by about 40% with CaF_(2) and by 55%-60% with CaCl_(2).The reaction model f(α)was also changed from contracting volume(R3)to 3-D diffusion models with D3 for CaCl_(2) and D4 for CaF_(2).This study provides valuable information on the mechanism and kinetics of calcium carbide nitridation reaction and new insights into the improvement of the lime-nitrogen process using calcium-based additives.

关键词： lime-nitrogen calcium carbide calciumbased additive thermogravimetric analysis nonisothermal kinetics

Neural stem cell-derived exosomes promote mitochondrial biogenesis and restore abnormal protein distribution in a mouse model of Alzheimer's disease

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Neural Regeneration Research 2024年第7期19卷 1593-1601页

作者： Bo Li Yujie Chen Yan Zhou Xuanran Feng Guojun Gu Shuang han Nianhao Cheng Yawen Sun Yiming zhang Jiahui Cheng qi zhang Wei zhang Jianhui Liu Department of Radiology Renji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghaiChina Morphology and Spatial Multi-Omics Technology Platform Shanghai Institute of Nutrition and HealthChinese Academy of SciencesShanghaiChina Department of Anesthesiology Tongji HospitalSchool of MedicineTongji UniversityShanghaiChina Department of Blood Transfusion Huashan HospitalFudan UniversityShanghaiChina

Mitochondrial dysfunction is a hallmark of Alzheimer’s *** previously showed that neural stem cell-derived extracellular vesicles improved mitochondrial function in the cortex of AP P/PS1 *** Alzheimer’s disease affects the entire brain,further research is needed to elucidate alterations in mitochondrial metabolism in the brain as a ***,we investigated the expression of several important mitochondrial biogenesis-related cytokines in multiple brain regions after treatment with neural stem cell-derived exosomes and used a combination of whole brain clearing,immunostaining,and lightsheet imaging to clarify their spatial ***,to clarify whether the sirtuin 1(SIRT1)-related pathway plays a regulatory role in neural stem cell-de rived exosomes interfering with mitochondrial functional changes,we generated a novel nervous system-SIRT1 conditional knoc kout AP P/PS1mouse *** findings demonstrate that neural stem cell-de rived exosomes significantly increase SIRT1 levels,enhance the production of mitochondrial biogenesis-related fa ctors,and inhibit astrocyte activation,but do not suppress amyloid-β***,neural stem cell-derived exosomes may be a useful therapeutic strategy for Alzheimer’s disease that activates the SIRT1-PGC1αsignaling pathway and increases NRF1 and COXIV synthesis to improve mitochondrial *** addition,we showed that the spatial distribution of mitochondrial biogenesis-related factors is disrupted in Alzheimer’s disease,and that neural stem cell-derived exosome treatment can reverse this effect,indicating that neural stem cell-derived exosomes promote mitochondrial biogenesis.

关键词： Alzheimer’s disease mitochondrial biogenesis neural stem cell-derived exosome SIRT1-PGC1α regional brain distribution whole brain clearing and imaging

Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui zhang qi Meng Zhi-Ming Ma Academy of Mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional *** to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants

HvMPK4 phosphorylates HvWRKY1 to enhance its suppression of barley immunity to powdery mildew fungus

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Journal of Genetics and Genomics 2024年第3期51卷 313-325页

作者： Pengya Xue Ling zhang Renchun Fan Yanan Li Xinyun han Ting qi Lifang Zhao Deshui Yu qian-Hua Shen State Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental BiologyInnovation Academy for Seed DesignChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Biotic Interactions College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Department of Nutritional Sciences&Toxicology University of CaliforniaBerkeleyCA 94720USA Lushan Botanical Garden Chinese Academy of ScienceJiujiangJiangxi 332900China

Mitogen-activated protein kinase(MAPK)cascades play important roles in disease resistance in model plant ***,the functions of MAPK signaling pathways in crop disease resistance are largely *** we report the function of HvMKK1-HvMPK4-HvWRKY1 module in barley immune ***4 is identified to play a negative role in barley immune response against Bgh,as virus-induced gene silencing of HvMPK4 results in enhanced disease resistance whilst stably overexpressing HvMPK4 leads to super-susceptibility to Bgh ***,the barley MAPK kinase HvMKK1 is found to specifically interact with HvMPK4,and the activated HvMKK1^(DD) variant specifically phosphorylates HvMPK4 in ***,the transcription factor HvWRKY1 is identified to be a downstream target of HvMPK4 and phosphorylated by HvMPK4 in vitro in the presence of HvMKK1^(DD).Phosphorylation assay coupled with mutagenesis analyses identifies S122,T284,and S347 in HvWRKY1 as the major residues phosphorylated by ***1 is phosphorylated in barley at the early stages of Bgh infection,which enhances its suppression on barley immunity likely due to enhanced DNA-binding and transcriptional repression *** data suggest that the HvMKK1-HvMPK4 kinase pair acts upstream of HvWRKY1 to negatively regulate barley immunity against powdery mildew.

关键词： Barley MPK4 WRKY1 Phosphorylation Disease resistance Powdery mildew

Mechanical behaviors of warm and ice-rich frozen soil stabilized with sulphoaluminate cement

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Journal of Mountain Science 2024年第1期21卷 335-345页

作者： WANG Honglei zhang Hu zhang Jianming zhang qi YIN Zhenhua State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China School of Civil Engineering and Transportation Northeast Forestry UniversityHarbin 150040China National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment CCCC First Highway Consultants Co.LtdXi'an 710065China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

The warm and ice-rich frozen soil is characterized by high unfrozen water content, low shear strength and large compressibility, which is unreliable to meet the stability requirements of engineering infrastructures and foundations in permafrost regions. In this study, a novel approach for stabilizing the warm and ice-rich frozen soil with sulphoaluminate cement was proposed based on chemical stabilization. The mechanical behaviors of the stabilized soil, such as strength and stress-strain relationship, were investigated through a series of triaxial compression tests conducted at -1.0℃, and the mechanism of strength variations of the stabilized soil was also explained based on scanning electron microscope test. The investigations indicated that the strength of stabilized soil to resist failure has been improved, and the linear Mohr-Coulomb criteria can accurately reflect the shear strength of stabilized soil under various applied confining pressure. The increase in both curing age and cement mixing ratio were favorable to the growth of cohesion and internal friction angle. More importantly, the strength improvement mechanism of the stabilized soil is attributed to the formation of structural skeleton and the generation of cementitious hydration products within itself. Therefore, the investigations conducted in this study provide valuable references for chemical stabilization of warm and ice-rich frozen ground, thereby providing a basis for in-situ ground improvement for reinforcing warm and ice-rich permafrost foundations by soil-cement column installation.

关键词： Permafrost regions Frozen soil Mechanical behavior Chemical stabilization Ground improvement Ground modification

Cobalt(Ⅲ)hydride HAT mediated enantioselective intramolecular hydroamination access to chiral pyrrolidines

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Science China Chemistry 2024年第6期67卷 2002-2008页

作者： qi Meng Tao qin Huanran Miao Ge zhang qian zhang Jilin Province Key Laboratory of Organic Functional Molecular Design&Synthesis Department of ChemistryNortheast Normal UniversityChangchun130024China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032China

Enantioenriched pyrrolidines and derivatives are ubiquitous substructures in compounds of importance to medicinal and biological ***,we report an efficient cobalt-catalyzed intramolecular asymmetric hydroamination reaction that produces chiral pyrrolidines with good to excellent yield and *** with previously reported radicalinvolved methodologies for enantioenriched pyrrolidines,these conditions feature two elegant versatilities,enabling(1)the use of cobalt-catalyzed hydrogen atom transfer(HAT)to generate organocobalt intermediates that bring radical reaction to organometallic chemistry,and(2)enantioselective intramolecular C-N bond forging through an S_(N)2-like displacement involving dynamic kinetic resolution(DKR).This approach provides a new alternative and efficient methodology for enantioselective radical-involved C-N bond construction that can be used in the synthesis of both chiral pyrrolidines and homologous nitrogen heterocycles.

关键词： asymmetric catalysis radical hydroamination cobalt catalysis hydrogen atom transfer

A vicinal oxygen chelate protein facilitates viral infection by triggering the unfolded protein response in Nicotiana benthamiana

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Journal of Integrative Plant Biology 2024年第7期66卷 1481-1499页

作者： Zhihong Guo Ning Jiang Menglin Li Hongfang Guo qi Liu Xinyu qin Zongying zhang Chenggui han Ying Wang Ministry of Agriculture and Rural Affairs Key Laboratory of Pest Monitoring and Green Management College of Plant ProtectionChina Agricultural UniversityBeijing 100193China

Vicinal oxygen chelate(VOC)proteins are members of an enzyme superfamily with dioxygenase or non-dioxygenase ***,the biological functions of VOC proteins in plants are poorly ***,we show that a VOC in Nicotiana benthamiana(NbVOC1)facilitates viral ***1 was significantly induced by infection by beet necrotic yellow vein virus(BNYVV).Transient overexpression of NbVOC1 or its homolog from Beta vulgaris(BvVOC1)enhanced BNYVV infection in ***,which required the nuclear localization of *** with this result,overexpressing NbVOC1 facilitated BNYVV infection,whereas,knockdown and knockout of NbVOC1 inhibited BNYVV infection in transgenic *** ***1 interacts with the basic leucine zipper transcription factors bZIP17/28,which enhances their self-interaction and DNA binding to the promoters of unfolded protein response(UPR)-related *** propose that bZIP17/28 directly binds to the NbVOC1 promoter and induces its transcription,forming a positive feedback loop to induce the UPR and facilitating BNYVV ***,our results demonstrate that NbVOC1 positively regulates the UPR that enhances viral infection in plants.

关键词： beet necrotic yellow vein virus bZIP17/28 Nicotiana benthamiana unfolded protein response VOC1

Dynamic Scene Graph Generation of Point Clouds with Structural Representation Learning

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Tsinghua Science and Technology 2024年第1期29卷 232-243页

作者： Chao qi Jianqin Yin Zhicheng zhang Jin Tang School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China Standard and Metrology Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

Scene graphs of point clouds help to understand object-level relationships in the 3D *** graph generation methods work on 2D structured data,which cannot be used for the 3D unstructured point cloud *** point-cloud-based methods generate the scene graph with an additional graph structure that needs labor-intensive manual *** address these problems,we explore a method to convert the point clouds into structured data and generate graphs without given ***,we cluster points with similar augmented features into groups and establish their relationships,resulting in an initial structural representation of the point ***,we propose a Dynamic Graph Generation Network(DGGN)to judge the semantic labels of targets of different *** dynamically splits and merges point groups,resulting in a scene graph with high *** show that our methods outperform other baseline *** output reliable graphs describing the object-level relationships without additional manual labeled data.

关键词： scene graph generation structural representation point cloud

Feasibility of medical radioisotope production based on the proton beams at China Spallation Neutron Source

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Nuclear Science and Techniques 2024年第6期35卷 26-39页

作者： Bing Jiang Bin-Bin Tian han-Tao Jing qi-Fan Dong Spallation Neutron Source Science Center Dongguan 523803China Institute of High Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China University of Chinese Academy of Sciences Beijing 100049China

The utilization of a proton beam from the China Spallation Neutron Source(CSNS)for producing medical radioisotopes is appealing owing to its high current intensity and high *** medical isotope production based on the proton beam at the CSNS is significant for the development of future radiopharmaceuticals,particularly for theα-emitting *** production yield and activity of typical medical isotopes were estimated using the FLUKA *** results indicate that the 300-MeV proton beam with a power of 100 kW at CSNS-II is highly suitable for proof-of-principle studies of most medical *** particular,this proton beam offers tremendous advantages for the large-scale production of alpha radioisotopes,such as 225Ac,whose theoretical production yield can reach approximately 57 Ci/*** on these results,we provide perspectives on the use of CSNS proton beams to produce radioisotopes for medical applications.

关键词： CSNS proton beam Medical isotope production α-Emitting radionuclides Nuclidic purity analysis