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Stress relaxation properties of calcium silicate hydrate:a molecular dynamics study

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 97-115页

作者： Zhicheng geng Shengwen TANG Yang WANG Hubao A Zhen HE kai WU Lei WANG State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education School of Materials Science and EngineeringTongji UniversityShanghai200092China College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an710055China

The time-dependent viscoelastic response of cement-based materials to applied deformation is far from fully understood at the atomic *** silicate hydrate(C-S-H),the main hydration product of Portland cement,is responsible for the viscoelastic mechanism of cement-based *** this study,a molecular model of C-S-H was developed to explain the stress relaxation characteristics of C-S-H at different initial deformation states,Ca/Si ratios,temperatures,and water contents,which cannot be accessed *** stress relaxation of C-S-H occurs regardless of whether it is subjected to initial shear,tensile,or compressive deformation,and shows a heterogeneous *** plays a crucial role in the stress relaxation process.A large Ca/Si ratio and high temperature reduce the cohesion between the calcium-silicate layer and the interlayer region,and the viscosity of the interlayer region,thereby accelerating the stress relaxation of *** effect of the hydrogen bond network and the morphology of C-S-H on the evolution of the stress relaxation characteristics of C-S-H at different water contents was elucidated by nonaffine mean squared *** results shed light on the stress relaxation characteristics of C-S-H from a microscopic perspective,bridging the gap between the microscopic phenomena and the underlying atomic-level mechanisms.

关键词： Calcium silicate hydrate(C-S-H) Stress relaxation Ca/Si ratio Temperature Water content Atomic simulation

One-pot and One-step Cu(0)-mediated Reversible-Deactivation Radical Polymerization of N-Isopropylacrylamide(NIPAM) in Water

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Chinese Journal of Polymer Science 2024年第1期42卷 1-6,I0004页

作者： zi-Shan Li Jing Lyu Bei Qiu Ying-Hao Li Ruth Foley Ri-Jian Song Melissa Johnson Qiang geng Wen-Xin Wang Institute of Precision Medicine(AUST-IPM) Anhui University of Science and TechnologyHuainan 232001China Charles Institute of Dermatology School of MedicineUniversity College DublinDublin D04 V1W8Ireland

Copper(0)-mediated reversible-deactivation radical polymerization(Cu(0)-mediated RDRP) of the water-soluble monomer Nisopropylacrylamide(NIPAM) has been challenging with the problems of high dispersity, poor control over the molecular weights(MWs) or complex or multi reaction steps, etc. In this work, we report the well-controlled polymerization of NIPAM in water via a facile one-pot and one-step Cu(0)-mediated RDRP. The results of this approach show that the key for kicking off the Cu(0)-mediated NIPAM RDRPs is to ensure sufficient Cu~I at the very beginning, and the key to achieve a well-controlled chain growth is to provide adequate deactivation strength during the polymerization process. For NIPAM, which has a high propagation rate constant, the deactivation control can be effectively enhanced by extra adding deactivator(i.e., Cu~II) to the system. Moreover, a low reaction temperature(4 ℃) is necessary in the controlled synthesis of higher MW poly(Nisopropylacrylamide)(PNIPAM) to avoid the compromise in control caused by the phase transition from its lower critical solution temperature(LCST). Through this new kinetically controlled strategy, PNIPAMs with well-defined structure, narrow molecular weight distributions(MWDs) and varied MWs were successfully achieved.

关键词： Cu(0)-mediated RDRP N-isopropylacrylamide Propagation Deactivation Reaction parameters

Metal ion metabolism and osteoporosis:possible implications for pharmaceutical biotechnology and tissue engineering

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Science China(Life Sciences) 2024年第8期67卷 1763-1765页

作者： Huaqiang Tao Qiufei Wang kai Chen Pengfei Zhu Ye Gu Dechun geng Department of Orthopedics The First Affiliated Hospital of Soochow UniversitySuzhou 215000China Department of Orthopedics Changshu Hospital Affiliated to Soochow UniversityFirst People’s Hospital of Changshu CityChangshu 215506China Department of Orthopedics Hai’an People’s HospitalHai’an 226600China

Osteoporosis(OP)is a systemic metabolic bone disease characterized by low bone mass,damage to bone microstructure and increased bone *** imbalance of functional coupling between osteoblasts and osteoclasts contributes to the pathological progression of the disease(Rachner et al.,2011).The pathogenesis of OP is precisely controlled by the complex regulatory network of the bone *** elements,although present in small amounts in the body,are essential for their influence on the physiological activities of *** ions act as effective catalysts and have applications in all stages of cell biochemical evolution(Qian et al.,2021).Bone tissue contains various metal elements,and metal ions play indispensable roles in bone metabolism at the molecular and cellular levels(Luo et al.,2023).However,it is important to note that these metal ions can also contribute to the progression of OP by influencing multiple cellular pathways either directly or indirectly.

关键词： metabolism biotechnology indispensable

Highly Stretchable and Tunable Thermo-fluorochromic Polymer Elastomer through Eu^(3+)Dynamic Coordination Cross-linking

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Chinese Journal of Polymer Science 2024年第10期42卷 1449-1458,I0008页

作者： Qiu-Li Tan kai Gou Jing-Zhi Tang Ming-Hui Wei Chong Wang Yi-Jing Nie geng-Sheng Weng School of Materials Science and Chemical Engineering State Key Laboratory Base of Novel Functional Materials and Preparation ScienceNingbo UniversityNingbo315211China Institute of Polymer Materials School of Materials Science and EngineeringJiangsu UniversityZhenjiang212013China

Thermochromic polymers with tunable thermochromism,high stretchability and mechanical strength are of interests for optical information storage and *** this work,we demonstrate a new design of thermo-fluorochromic carboxylated nitrile butadiene rubber(XNBR)elastomer cross-linked by Eu^(3+)-COOH dynamic coordination with deprotonated imidazole(DPIm)as the ancillary *** presence of DPIm not only improves the mechanical strength and stretchability,but also dramatically intensifies the fluorescence emission and lifetime of the Eu-containing *** elastomer behaves reversible thermo-fluorochromism with easily tunable transition temperature and emission intensity by the simple change of the deprotonation degree of *** facile tunable thermo-fluorochromism,exceptional mechanical strength,and high stretchability(up to about 5000%)enable the Eu-containing XNBR elastomer with potential applications in soft electronics where optical information storage and encryption are required.

关键词： Dynamic coordination Thermochromism Highly stretchable Elastomer Europium

Heme oxygenase 1 linked to inactivation of subchondral osteoclasts in osteoarthritis

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第6期25卷 513-528页

作者： Miao CHU Guangdong CHEN kai CHEN Pengfei ZHU Zhen WANG Zhonglai QIAN Huaqiang TAO Yaozeng XU Dechun geng Department of Orthopedics the First Affiliated Hospital of Soochow UniversitySuzhou 215006China Department of Orthopedics Yixing People’s HospitalYixing 214200China Department of Orthopedics Hai’an People’s HospitalHai’an 226600China Department of Orthopedics Suzhou Kowloon HospitalShanghai Jiao Tong University School of MedicineSuzhou 215028China

Osteoarthritis(OA)is a chronic progressive osteoarthropathy in the *** activation plays a crucial role in the occurrence of subchondral bone loss in early ***,the specific mechanism of osteoclast differentiation in OA remains *** our study,gene expression profiles related to OA disease progression and osteoclast activation were screened from the Gene Expression Omnibus(GEO)***2R and Funrich analysis tools were employed to find differentially expressed genes(DEGs).Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses demonstrated that chemical carcinogenesis,reactive oxygen species(ROS),and response to oxidative stress were mainly involved in osteoclast differentiation in OA subchondral ***,fourteen DEGs that are associated with oxidative stress were *** first ranked differential gene,heme oxygenase 1(HMOX1),was selected for further *** results showed that osteoclast activation in the pathogenesis of OA subchondral bone is accompanied by the downregulation of *** was revealed to inhibit osteoclastogenesis by targeting HMOX1 and upregulating the expression of antioxidant protein in ***,carnosol was found to alleviate the severity of OA by inhibiting the activation of subchondral osteoclasts in *** research indicated that the activation of osteoclasts due to subchondral bone redox dysplasia may serve as a significant pathway for the advancement of *** HMOX1 in subchondral osteoclasts may offer novel insights for the treatment of early OA.

关键词： Osteoclast Oxidative stress Osteoarthritis(OA) Heme oxygenase 1(HMOX1) Carnosol

Copper-Free Click Chemistry-Mediated Assembly of Single Quantum Dot Nanosensor for Accurately Monitoring Locus-Specific m^(6)A in Cancer Cells

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Chinese Journal of Chemistry 2024年第5期42卷 499-504页

作者： Yue-Ying Li Ning-Ning Zhao Yi-Xuan geng Qian Han Jian-Ge Qiu Bing-Hua Jiang zi-Yue Wang Chun-Yang Zhang Translational Medicine Center The First Affiliated Hospital of Zhengzhou UniversityThe Academy of Medical SciencesHenan Institute of Medical and Pharmaceutical Sciences BGI CollegeZhengzhou UniversityZhengzhouHenan450052 China College of Chemistry Chemical Engineering and Materials ScienceShandong Normal UniversityJinanShandong250014 China School of Chemistry and Chemical Engineering Southeast UniversityNanjingJiangsu211189 China

N6-methyladenosine(m^(6)A)plays an important role in embryogenesis,nuclear export,transcription splicing,and protein translation ***,we demonstrate a copper-free click chemistry-mediated assembly of single quantum dot(QD)nanosensor for accurately monitoring locus-specific m^(6)A in cancer *** m^(6)A-sensitive endoribonuclease MazF can digest the unmethylated A-RNA,and the intact m^(6)A-RNA then hybridizes with DNA probes a and b to produce a sandwich hybrid,initiating the click chemistry to generate probe a–b ligation product via first tandem ligation detection reaction(LDR)***,DNA probes c and d can hybridize with the probe a–b ligation product to generate the probe c–d ligation product via second LDR *** LDR cycles can be repeated through denaturation and annealing reaction to generate abundant biotin-/fluorophore-modified probe c–d ligation products that can easily assemble on the QD surface to induce distinct fluorescence resonance energy transfer(FRET)between QD and *** assay can be homogenously performed without the involvement of copper catalyst,m^(6)A-specific antibody,radioactive labeling,ligase enzyme,enzymatic reverse transcription,and next-generation ***,it can discriminate even 0.01% m^(6)A level in complex samples and accurately measure cellular m^(6)A-RNA expression,providing a promising avenue for clinical diagnostics and biomedical research.

关键词： RNA methylation Click chemistry Förster resonance energy transfer Biosensor Cancer

Mixed Dead-time Effect Suppression Strategy for Modular Multilevel Converters

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1075-1084页

作者： Zhi geng Minxiao Han School of Electrical and Electronic Engineering North China Electric Power UniversityBeijing 102206China IEEE

Dead time is necessary for the coupled power switches to prevent shoot-through,especially in the modular multilevel converters(MMCs)with a large number of power *** paper proposes a dead-time effect suppression strategy for MMCs with nearest level *** operational principles of MMCs are first *** to the operational features of MMCs,the method that removes a switching signal from the coupled switches and the reduced switching frequency voltage balancing algorithms(RSFVBAs)are mixed in the proposed *** the intervals that are furthest away from the zerocrossing points(ZCP)of arm currents,the single switching signal method can completely eliminate the dead-time effect(DTE).Alternatively,the DTE is suppressed by the RSFVBA in intervals that are close to the *** the combination of the two methods,the dependence of the DTE suppression method on currents is reduced and the influences of ZCP are also released without degrading the normal operation performance of ***,the output performance of MMCs is improved and the voltage stress on the arm inductor dramatically ***,the validation of the method is verified by the simulation results with the professional tool Matlab/Simulink.

关键词： Dead-time effect modular multilevel converters switching frequency voltage balancing algorithm

Investigation and measurement of old building response to the overlapped shield tunnel of multiple schemes in the sandy cobble stratum

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Underground Space 2024年第2期15卷 260-274页

作者： Xue Li Aopeng geng School of Geoscience and Technology Southwest Petroleum UniversityChengduSichuan 610500China China Railway Construction Bridge Engineering Bureau Group Co. Ltd.Tianjin 300300China

Ground movements due to tunneling are becoming increasingly critical as buildings are located around construction *** study proposes a new combined reinforcement method using a foundation grouting oblique pipe *** former improves the bearing capacity of the subsoil,and the latter blocks the transmission of soil deformation,which weakens the influence of construction during overlapped tunnel *** on this new method,a case study of the shield tunneling response to an old building in Line 6 of China’s Chengdu Metro is ***,three-dimensional numerical models without reinforcement,traditional foundation grouting reinforcement,and the new combined reinforcement schemes were *** numerical simulation performance was verified using a set of field instrumentation data,which demonstrated that the old building response to the overlapped tunnels was under control,and the maximum deformation,angular distortion,and principal tensile strain of the building were 5.25 mm,5.1010–6 rad/m,and 0.0081%,*** with the traditional reinforcement scheme,the deformation,angular distortion,and principal tensile strain in the combined reinforcement scheme were reduced by 54.78%,71.02%,and 70.22%,*** results have important implications for the design and construction of shield tunnels and their response to old buildings.

关键词： Overlapped tunnels Reinforcement schemes Under-crossing Old building Numerical simulation

Boosting electrocatalytic nitrate reduction to ammonia via Cu_(2)O/Cu(OH)_(2)heterostructures promoting electron transfer

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Nano Research 2024年第6期17卷 4898-4907页

作者： Jing geng Sihan Ji Anhui Province International Research Center on Advanced Building Materials School of Materials Science and Chemical EngineeringAnhui Jianzhu UniversityHefei 230601China Anhui Province Key Laboratory of Advanced Building Materials Anhui Jianzhu UniversityHefei 230601China School of Energy Materials and Chemical Engineering Hefei UniversityHefei 230601China

Electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NH_(3))offers a viable approach for sustainable NH_(3)production and environmental ***(Cu)possesses a distinctive electronic structure,which can augment the reaction kinetics of NO_(3)^(−)and impede hydrogen evolution reaction(HER),rendering it a promising contender for the electrosynthesis of NH_(3)from NO_(3)^(−).Nevertheless,the role of Cu_(2)O in copper-based catalysts still requires further investigation for a more comprehensive ***,the Cu_(2)O/Cu(OH)_(2)heterostructures are successfully fabricated through liquid laser irradiation using CuO nanoparticles as a *** and theoretical researches reveal that Cu_(2)O/Cu(OH)_(2)heterostructure exhibits enhanced electrocatalytic performance for NO_(3)^(−)to NH_(3)because Cu(OH)_(2)promotes electron transfer and reduces the valence state of Cu active site in Cu_(2)***−0.6 V(*** hydrogen electrode(RHE)),the NH_(3)yield reaches its maximum at 1630.66±29.72μg·h^(−1)·mgcat^(−1),while the maximum of Faraday efficiency(FE)is 76.95%±5.51%.This study expands the technical scope of copper-based catalyst preparation and enhances the understanding of the electrocatalytic mechanism of NO_(3)^(−)to NH_(3).

关键词： Cu_(2)O/Cu(OH)_(2)heterostructures electron transfer ammonia synthesis electrocatalysts nitrate