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Fabrication of self-assembling nanofibers with optimal cell uptake and therapeutic delivery efficacy

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Bioactive Materials 2017年第4期2卷 260-268页

作者： dawei xu Damien SKSamways He Dong Department of Chemistry&Biomolecular Science Clarkson UniversityPotsdamUSA Department of Biology Clarkson UniversityPotsdamUSA

Effective strategies to fabricate finite organic nanoparticles and understanding their structure-dependent cell interaction is highly important for the development of long circulating nanocarriers in cancer *** this contribution,we will capitalize on our recent development of finite supramolecular nanofibers based on the self-assembly of modularly designed cationic multidomain peptides(MDPs)and use them as a model system to investigate structure-dependent cell penetrating *** selfassembled into nanofibers with high density of cationic charges at the fiber-solvent interface to interact with the cell ***,despite the multivalent charge presentation,not all fibers led to high levels of membrane activity and cellular *** flexibility of the cationic charge domains on self-assembled nanofibers plays a key role in effective membrane *** were found to sacrifice their dimension,thermodynamic and kinetic stability for a more flexible charge domain in order to achieve effective membrane *** increased membrane activity led to improved cell uptake of membrane-impermeable chemotherapeutics through membrane pore *** vitro cytotoxicity study showed co-administering of water-soluble doxorubicin with membrane-active peptide nanofibers dramatically reduced the IC50 by eight folds compared to drug *** these detailed structure and activity studies,the acquired knowledge will provide important guidelines for the design of a variety of supramolecular cell penetrating nanomaterials not limited to peptide assembly which can be used to probe various complex biological processes.

关键词： Supramolecular assembly Cell penetrating peptide Drug delivery Cell uptake Membrane activity

Telomerase as a “stemness” enzyme

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Science China(Life Sciences) 2014年第6期57卷 564-570页

作者： KONG Feng ZHENG ChengYun xu dawei Central Research Laboratory the Second Hospital of Shandong University Department of Hematology the Second Hospital of Shandong University Department of Medicine Division of Hematology and Centre for Molecular MedicineKarolinska Institutet and Karolinska UniversityHospital Solna

Pluripotent or multipotent stem cells are involved in development and tissue homeostasis;they have the ability to self-renew and differentiate into various types of functional *** maintain these properties,stem cells must undergo sustained or unlimited proliferation that requires the stabilization of telomeres,which are essential for chromosome end ***,an RNA-dependent DNA polymerase,synthesizes telomeric *** the lengthening of telomeres the lifespans of cells are extended,or indefinite proliferation is conferred;this is intimately associated with stem cell *** review highlights our current understanding of telomerase as a"stemness"enzyme and discusses the underlying implications.

关键词： stem cells telomerase telomere genomic stability iPS cells TERC TERT

Short-term effects of fire disturbance on CH4 emission from forested wetlands in the Xiaoxing’an Mountains, Northeast China

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Journal of Forestry Research 2019年第3期30卷 969-979页

作者： Han Gu Wenyu Zheng dawei xu Changcheng Mu College of Architecture and Urban Planning Chongqing Jiaotong UniversityChongqing 40074People’s Republic of China Postdoctoral Program of Landscape Architecture Northeast Forestry UniversityHarbin 150040People’s Republic of China School of Forestry Northeast Forestry University Harbin 150040People’s Republic of China

Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) after fire disturbance in the Xiaoxing’an Mountains. The results showed the following: during the growing season, the annual CH4 emission distribution ranged from - 0.001 ± 0.012 to 22.373 ± 3.650 mg m^-2 h^-1;mild fire caused the swamp CH4 emission flux of tussock, shrub, Alnus sibirica and birch swamp to increase by 56.0–524.7%;at low water levels, temperature had a significant influence on the swamp type, and the correlation between the methane emission flux and temperature was significantly strengthened;after a fire disturbance, methane emissions from all types of marsh were highest in summer and second highest in autumn, with a weak absorption in spring;and along the water environment gradient of the transition zone, the CH4 emission flux presented a decreasing trend in its spatial distribution pattern.

关键词： Xiaoxing’an Mountains Forest swamp CH4 emission Fire disturbance

Synthesis of comb bipolymers and their pour point depressing properties

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Petroleum Science 2014年第1期11卷 155-160页

作者： Zhang Changqiao Gao Congcong Gao Fengfeng Wang Jian Zhang dawei Wang Yan xu dawei School of Chemistry and Chemical Engineering Shandong University Shandong Quality Certification Centre Shandong Product Quality Supervision & Inspection Research Institute

A bipolymer maleic anhydride-methyl acrylate （MAMA） was synthesized from maleic anhydride and methyl acrylate based on molecular *** further reacted with oleylamine or octadecyl alcohol to generate two comb polymers called Oleamide-MAMA （NMAMA） and OctadecanolMAMA （OMAMA）,*** structure of both the polymers was confirmed by their infrared spectral analysis （IR）,gel permeation chromatography analysis （GPC） and differential scanning calorimeter （DSC）.Moreover,the pour point depressing （PPD） properties of these comb polymers were examined *** results showed that besides the molecular weight and concentration of the polymers,the length of side chains and the number of functional groups also had great influence on the pour point depressing *** π bonds and hydrogen bonds between depressants were the key factors for improving the pour point depressing *** results suggest that both OMAMA and NMAMA are potential pour point depressants for industry.

关键词： Maleic anhydride comb polymers pour point depressant hydrogen bonds molecular simulation

Platinum nanowires catalyzed direct amidation of aldehydes and amines

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Science China Chemistry 2016年第4期59卷 478-481页

作者： dawei xu Linyan Shi Danhua Ge xueqin Cao Hongwei Gu Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University

Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert-butylhydroperoxide(TBHP) as the oxidant. Influence of factors, such as the catalyst, solvents, and the reaction temperature, were studied to determine the optimal reaction conditions. In addition, we explored the substrate generality and observed excellent yields.

关键词： aldehyde amine amide amidation Pt nanowires

Managed grassland alters soil N dynamics and N2O emissions in temperate steppe

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Journal of Environmental Sciences 2018年第4期30卷 20-30页

作者： Lijun xu Xingliang xu xuejuan Tang Xiaoping Xin Liming Ye Guixia Yang Huajun Tang Shijie Lv dawei xu Zhao Zhang Hulunber Grassland Ecosystem Observation and Research Station Institute of Agricultural Resources and Regional Planning of ChineseAcademy of Agricultural Sciences Beijing 100081 China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100081 China Department of Geology (WE13) Ghent University 9000 Gent Belgium Science College of Inner Mongolia Agricultural University Hohhot Inner Mongolia 010018 China

Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen（N） dynamics and nitrous oxide（N2O） emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N2O emissions by field experiments in Hulunber in northern China. Soil（0-10 cm）, nitrate（NO3-）,ammonium（NH4＋）, and microbial N were measured in plots in a temperate steppe（Leymus chinensis grassland） and two managed grasslands（Medicago sativa and Bromus inermis grasslands） in 2011 and 2012. The results showed conversion of L. chinensis grassland to *** or B. inermis grasslands decreased concentrations of NO3--N, but did not change NH4-N . Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to ***, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa（i.e., a legume grass） increased N2O emissions by 26.2%, while the conversion to the B. inermis（i.e., a non-legume grass） reduced N2O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO3-＋-N and NH4-N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N2O emissions.

关键词： Temperate steppe Managed grassland Land use Nitrogen mobility N2O emissions

Bitcoin Network Measurement and a New Approach to Infer the Topology

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China Communications 2022年第10期19卷 169-179页

作者： Ruiguang Li Jiawei Zhu dawei xu Fudong Wu Jiaqi Gao Liehuang Zhu School of Cyberspace Science and Technology Beijing Institute of TechnologyBeijing 100081China National Computer Network Emergency Response Technical Team/Coordination Center Beijing 100029China School of Cyberspace Security Changchun UniversityChangchun 130022China

Bitcoin has made an increasing impact on the world's economy and financial order,which attracted extensive attention of researchers and regulators from all over the *** previous studies had focused more on the transaction layer,but less on the network *** this paper,we developed BNS(Bitcoin Network Sniffer),which could find and connect nodes in the Bitcoin network,and made a measurement in *** collected nearly 4.1 million nodes in 1.5 hours and identified 9,515 reachable *** counted the reachable nodes'properties such as:service type,port number,client version and geographic *** addition,we analyzed the stability of the reachable nodes in depth and found nearly 60%kept stable during 15 ***,we proposed a new approach to infer the Bitcoin network topology by analyzing the Neighbor Addresses of Adjacent Nodes and their timestamps,which had an accuracy over 80%.

关键词： Bitcoin network reachable nodes node properties node stability network topology

Homogenous metallic deposition regulated by abundant lithiophilic sites in nickel/cobalt oxides nanoneedle arrays for lithium metal batteries

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Journal of Energy Chemistry 2023年第2期77卷 11-18,I0001页

作者： Fenqiang Luo dawei xu Yongchao Liao Minghao Chen Shuirong Li Dechao Wang Zhifeng Zheng Fujian Provincial Industry Technologies Development Base for New Energy Fujian Provincial Engineering and Research Center of Clean and High-valued Technologies for BiomassXiamen Key Laboratory for High-valued Conversion Technology of Agricultural BiomassCollege of EnergyXiamen UniversityXiamen 361102FujianChina China Fujian Innovation Laboratory of Energy Materials Science and Technology(Tan Kah Kee Innovation Laboratory) Xiamen 361102FujianChina

Although lithium(Li)metal delivers the highest theoretical capacity as a battery anode,its high reactivity can generate Li dendrites and"dead"Li during cycling,resulting in poor reversibility and low Li *** uniform Li plating/stripping is the core of solving these ***,we design a highly lithiophilic carbon film with an outer sheath of the nanoneedle arrays to induce homogeneous Li plating/*** excellent conductivity and 3D framework of the carbon film not only offer fast charge transport across the entire electrode but also mitigate the volume change of Li metal during *** abundant lithiophilic sites ensure stable Li plating/stripping,thereby inhibiting the Li dendritic growth and"dead"Li *** resulting composite anode allows for stable Li stripping/plating under 0.5 mA cm^(-2) with a capacity of 0.5 mA h cm^(-2) for 4000 h and 3 mA cm^(-2) with a capacity of3 mA h cm^(-2) for 1000 *** Ex-SEM analysis reveals that lithiophilic property is different at the bottom,top,or channel in the structu re,which can regulate a bottom-up uniform Li deposition *** cells paired with LFP show a stable capacity of 155 mA h g^(-1) under a current density of *** pouch cell can keep powering light-emitting diode even under 180°bending,suggesting its good flexibility and great practical applications.

关键词： Nickel/cobalt oxides Nanoneedle arrays Lithiophilic sites Lithium metal batteries

BUES: A Blockchain-Based Upgraded Email System

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China Communications 2022年第10期19卷 250-264页

作者： dawei xu Fudong Wu Liehuang Zhu Ruiguang Li Jiaqi Gao Yijie She School of Cyberspace Science and Technology Beijing Institute of TechnologyBeijing 100081China College of Cybersecurity Changchun UniversityChangchun 130022China National Internet Emergency Center Beijing 100081China

This paper focuses on the improvement of traditional email system architecture with the help of blockchain technology in the existing network environment. The improved system architecture can better improve the security and stability of the system. The email content is extracted and stored in the blockchain network to achieve regulatory traceability between the email service provider and the higher-level organization. In turn, A Blockchain-based Upgraded Email System(BUES) is proposed. The defects of the existing traditional email system are addressed. Firstly, the threat model of the traditional email system is analyzed, and solutions are proposed for various threats. Then a system architecture consisting of the blockchain network, email servers, and users are constructed. The implementation of BUES is carried out, and the related experimental process and algorithm steps are given. After the experimental analysis, it is shown that BUES can ensure the security, reliability, efficiency, and traceability of email transmission.

关键词： blockchain email service chaincode hyperledger fabric