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Floral Ontogeny of Two Species in Magnolia L.

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Journal of Integrative Plant Biology 2006年第10期48卷 1197-1203页

作者： Feng-xia xu South China Botanical Garden the Chinese Academy of Sciences Guangzhou 510650 China

Floral ontogeny is described in two species of genus Magnolia （Magnollaceae）, Magnolia alboserlcea Chun et C. Tsoong, and M. amoena Cheng, representing subgenus Magnolia and subgenus Yulani In Magnolia, by using scanning electron microscope （SEM）. The sequence of Initiation of floral organs Is from proximal to distal. The three distinct outermost and middle organs are Initiated in sequence, but ultimately form a single whorl, thus their ontogeny Is consistent with a sepal Interpretation. The last three tepals （petals） alternate with the preceding tepal whorl. The members of androeclum and gynoeclum arise spirally, although the androecium shows some Intermedlacy between a spiral and whorled arrangement. The carpel prlmordia initiate in group of four to five. The order of stamen Initiation within each tier Is not determined. The floral ontogeny Is remarkably homogeneous between the subgenus Magnolia and subgenus Yulani that does not support the resuming of genus Yulani.

关键词： floral ontogeny Magnolia albosericea Magnolia amoena subgenus Magnolia subgenus Yulania

Improved ethane conversion to ethylene and aromatics over a Zn/ZSM-5 and CaMnO^(3-δ) composite catalyst

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Journal of Energy Chemistry 2020年第12期29卷 161-166页

作者： Yan Zhang xia xu Heqing Jiang Key Laboratory of Biofuels Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101ShandongChina University of Chinese Academy of Sciences Beijing 100049China

Ethane conversion to ethylene and aromatics over Zn/zeolite catalysts is a promising technology for efficient exploitation of light alkanes. However, the reaction faces two major hurdles including the limited ethane conversion due to thermodynamics and the drastic catalyst deactivation by kinetical coke accumulation. Here we present a route to improve ethane conversion using a composite catalyst, involving Zn/HZSM-5 for ethane dehydroaromatization and CaMnO3-δperovskite for in situ selective hydrogen oxidation. The in situ H2 consumption shifts ethane dehydrogenation equilibrium to the desired side and can obviously increase the yield of target product. Furthermore, it is found that the in situ generated H2 O through H2 combustion can significantly suppress the coke formation and consequently enhance the stability of the composite catalyst. After 400 min reaction, a product yield of 23% was retained over the composite catalyst, almost a threefold increase with respect to the Zn/HZSM-5 reference(8%). It is anticipated that this novel composite catalyst combined with an efficient reactor technology may improve the viability of ethane aromatization in utilization.

关键词： Ethane aromatization Composite catalyst Zn/HZSM-5 CaMnO^(3-δ) Hydrogen consumption

Genome editing in insects: current status and challenges

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National Science Review 2019年第3期6卷 399-401页

作者： Jun xu xia xu Shuai Zhan Yongping Huang CAS Key Laboratory of Insect Developmental and Evolutionary Biology CAS Center for Excellence in Molecular Plant Sciences Shanghai Institute of Plant Physiology and Ecology Chinese Academy of Sciences

Insects constitute the largest group in the animal kingdom, and include many economically important species as well as pests. This abundance provides largescale genetic resources, and research on insects is beneficial from the perspectives of human health, agricultural production and basic science (Fig.1).The availability of many genetic tools has made Drosophila melanogaster a crucially important model organism

关键词： Genome editing in insects current status and challenges

Suppression of miR-17 Alleviates Acute Respiratory Distress-associated Lung Fibrosis by Regulating Mfn2

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Current Medical Science 2024年第5期44卷 964-970页

作者： Mei-xia xu Tao xu Ning AN Department of Critical Care Medicine Wuhan Fourth HospitalWuhan430033China Institute of Anesthesiology and Critical Care Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China

Objective Acute respiratory distress syndrome(ARDS)patients currently have relatively high mortality,which is associated with early lung *** study aimed to investigate whether miR-17 suppression could alleviate ARDS-associated lung fibrosis by regulating *** A mouse model of ARDS-related lung fibrosis was constructed via intratracheal instillation of *** expression level of miR-17 in lung tissues was detected via quantitative real time polymerase chain reaction(qRT-PCR).In the ARDS mouse model of lung fibrosis,the mitigating effects of miR-17 interference were evaluated via tail vein injection of the miR negative control or the miR-17 *** pathological changes in the lung tissue were examined via HE staining and Masson’s trichrome staining,and the underlying molecular mechanism was investigated via ELISA,qRT-PCR and Western *** Bleomycin-induced pulmonary fibrosis significantly increased collagen deposition and the levels of hydroxyproline(HYP)and *** with miR-17 significantly reduced the levels of HYP and miR-17 and upregulated the expression of *** intravenous injection of the miR-17 antagomir alleviated lung inflammation and reduced collagen *** addition,interference with miR-17 could upregulate LC3B expression,downregulate p62 expression,and improve mitochondrial *** Interfering with miR-17 can improve pulmonary fibrosis in mice by promoting mitochondrial autophagy via Mfn2.

关键词： miR-17 Mfn2 acute respiratory distress syndrome pulmonary fibrosis mitochondria

Nitrogen-,phosphorus-doped carbon-carbon nanotube CoP dodecahedra by controlling zinc content for high-performance electrocatalytic oxygen evolution

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Rare Metals 2020年第6期39卷 680-687页

作者： xia-xia Li Pei-Yao Zhu Qing Li Yu-xia xu Yan Zhao Huan Pang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225009China Guangling College Yangzhou UniversityYangzhou 225000China College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610068China

Here,N-and P-doped carbon-carbon nanotube CoP(NPC-CNTs-CoP)nanoparticles dodecahedra are achieved by multistep calcination of the Zn-doped zeolitic imidazolate framework ZIF-67 precursor(ZnCo-ZIF).In the structures,the presence of N and P atoms,abundant CNTs and the CoP nanoparticles can enhance electrochemical activity and promote the structural stability of *** the temperature increases,the Zn contents gradually reduce to zero,which provides more active sites for electrochemical ***,the high specific surface area and microporous behavior of NPC-CNTsCoP-9 make it excellent in electrocatalytic ***-CoP-9 shows a low overpotential of 224 mV at10 mA·cm^-2 in 1.0 mol·L^-1 KOH *** strategy of zeolitic imidazole framework-derived transition metal phosphides will provide a new sight for developing energy conversion materials.

关键词： Nitrogen Phosphorus Carbon Carbon nanotube CoP Oxygen evolution

An Optimal Stability Matching Algorithm for DAG Blockchain Based on Matching Theory

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Chinese Journal of Electronics 2021年第2期30卷 367-377页

作者： xia xu HUANG Jianhua ZHENG Hong TANG Ruicong East China University of Science and Technology

IOTA is a typical blockchain designed for IoT applications. The Markov chain monte carlo algorithm(MCMC) used in IOTA may lead to a large number of unverified blocks, which increases transaction delay to a certain extent. We propose a Stable matching algorithm(SMA) based on matching theory to stimulate nodes to verify blocks, thereby reducing the number of unverified blocks and the consensus delay. The structure of our Io T blockchain uses the Directed acyc1 ic graph(DAG)to improve the transaction processing capability. The nodes in the network are abstracted as transaction issuers and transaction verifiers. A verification service scheduling system is used to assign transactions to the verifiers and achieve the optimal matching. We designed a trust evaluation mechanism which offers verifiers references and awards to check transactions. The simulation results show that SMA can significantly reduce the number of orphan blocks and improve the transaction throughput, which helps to improve the reliability of the Io T blockchain.

关键词： stable matching algorithm directed acyclic graph verification service scheduling system blockchains SMA Markov processes transaction throughput IoT applications transaction verifiers transaction processing consensus delay Markov chain Monte Carlo algorithm Monte Carlo methods DAG blockchain optimal stability matching algorithm Internet of Things directed graphs scheduling computer network security transaction processing capability transaction issuers IoT blockchain IOTA orphan blocks

Biochemical Characterization of Translesion Synthesis by Sulfolobus acidocaldarius DNA Polymerases

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Chemical Research in Chinese Universities 2016年第2期32卷 226-233页

作者： PENG Li xia xu LIU Xipeng State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University Shanghai 200240 P R. China

To study the DNA synthesis mechanism of Sulfolobus acidocaldarius, a thermophilic species from Crenarehaeota, two DNA polymerases of B family（polB1 and polB3）, and one DNA polymerase of Y family（polIV） were recombinantly expressed, purified and biochemically characterized. Both DNA polymerases polBl（Saci_1537） and polB3（Saci_0074） possessed DNA polymerase and 3＇ to 5＇ exonuclease activities; however, both the activities of B3 were very inefficient in vitro. The polIV（Saci_0554） was a polymerase, not an exonuclease. The activities of all the three DNA polymerases were dependent on divalent metal ions Mn1＋ and Mg2＋. They showed the highest activity at pH values ranging from 8.0 to 9.5. Their activities were inhibited by KC1 with high concentration. The optimal reaction temperatures for the three DNA polymerases were between 60 and 70 ℃. Deaminated bases dU and dI on DNA template strongly hindered primer extension by the two DNA polymerases of B family, not by the DNA polymerase of Y family. DNA polymerase of Y Family bypassed the two AP site analogues dSpacer and propane on template more easily than DNA polymerases of B family. Our results suggest that the three DNA polymerases coordinate to fulfill various DNA synthesis in Sulfolobus acidocaldarius cell.

关键词： Archaeota Sulfolobus acidocaldarius DNA polymerase DNA damage DNA replication

Controllable synthesis and tunable photocatalytic activity of TiO2 nanowires via alcohol-thermal method

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Rare Metals 2019年第5期38卷 390-396页

作者： Zheng-xia xu An-Qi Wang Yong-Fa Zhu School of Civil Engineering and Mechanics Yanshan UniversityQinhuangdao 066004China Department of Chemistry Tsinghua UniversityBeijing 100084China

Titania nanowires(TiO2-NW)with tunable aspect ratios and morphologies were directly synthesized using a simple alcohol-thermal ***,ethanol and acetic acid were used as solvents and lithium ion was used as the capping agent to promote the conversion of titanium butoxide into *** morphologies and crystal phases of TiO2-NW were determined by the molar ratio of solvents and the content(mol%)of lithium *** band gap of TiO2-NW with pure anatase phase is slightly bigger than that of TiO2-NW with a mixture of anatase and rutile *** TiO2-NW could achieve effective decolorization of methyl blue(the decolorization rate is over 95%)after 35-min ultraviolet(UV)irradiation.

关键词： Nanowires TiO2 Photocatalysis Degradation Photocurrent

A review on prediction of casting defects in steel ingots:from macrosegregation to multi-defect model

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Journal of Iron and Steel Research International 2022年第12期29卷 1901-1914页

作者： Jun Li xiao-wei xu Neng Ren Ming-xu xia Jian-guo Li School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory of Advanced High-Temperature Materials and Precision Forming Shanghai 200240China

Due to the nature of the solute redistribution,the reduction in the solidification rate with time in a square root relationship,and the multiphase melt flow during the solidification,casting defects such as macrosegregation,shrinkage cavity,and porosity will inevitably occur in the steel ingot and intensify with the increase in ingot *** defects directly affect the performance of the final product and severely restrict the choice of subsequent thermal processing methods and process ***,the solidification defects including macrosegregation,shrinkage/porosity,and inclusions encountered in the preparation of large steel ingots and their formation mechanisms were *** development progress and the latest development of the macrosegregation model for steel ingots were introduced in detail,especially the latest progress in the coupling prediction of macrosegregation and shrinkage as well as macrosegregation and *** methods to reduce macrosegregation of ingots were discussed as ***,a new casting method called layered casting was introduced in *** method can effectively improve the uniformity of the macrostructure and reduce the macrosegregation of the large ingots and therefore is a promising method for preparing large ingots with high homogeneity.

关键词： Steel ingot Macrosegregation Numerical modeling Multiphase model Solidification defect