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Effects of air damping on quality factors of different probes in tapping mode atomic force microscopy

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Chinese Physics B 2024年第9期33卷 506-519页

作者： Yu Zeng Guo-Lin liu Jin-Hao liu zheng Wei School of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China

The AFM probe in tapping mode is a continuous process of energy dissipation,from moving away from to intermittent contact with the sample *** present,studies regarding the energy dissipation mechanism of this continuous process have only been reported sporadically,and there are no systematic explanations or experimental verifications of the energy dissipation mechanism in each stage of the continuous *** quality factors can be used to characterize the energy dissipation in TM-AFM *** this study,the vibration model of the microcantilever beam was established,coupling the vibration and damping effects of the microcantilever *** quality factor of the vibrating microcantilever beam under damping was derived,and the air viscous damping when the probe is away from the sample and the air squeeze film damping when the probe is close to the sample were *** addition,the mechanism of the damping effects of different shapes of probes at different tip–sample distances was *** accuracy of the theoretical simplified model was verified using both experimental and simulation methods.A clearer understanding of the kinetic characteristics and damping mechanism of the TM-AFM was achieved by examining the air damping dissipation mechanism of AFM probes in the tapping mode,which was very important for improving both the quality factor and the imaging quality of the TM-AFM *** study’s research findings also provided theoretical references and experimental methods for the future study of the energy dissipation mechanism of micro-nano-electromechanical systems.

关键词： TM-AFM quality factors air viscous damping air squeeze film damping

Single-atom catalysis for advanced oxidation and reduction systems in water decontamination

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Rare Metals 2024年第8期43卷 3576-3606页

作者： Jie Teng Jin-Hui Xu Wen-Xin Sun xue-Feng liu Xia Xu Guo-Shuai liu School of Urban Construction Changzhou UniversityChangzhou 213164China School of Environmental and Civil Engineering Jiangnan UniversityWuxi 214122China

Water scarcity is an escalating global crisis,posing a severe threat to populations ***,exploring various materials to remove emerging contaminants from freshwater sources has garnered significant *** this regard,single-atom catalysis(SACs) has emerged as a catalyst of scientific progress in water purification and treatment methodologies during recent *** exhibit exceptional catalytic activity,selectivity and stability,due to their near-perfect atom utilization,highly unsaturated coordination environment and uniform reaction ***,a comprehensive and critical review encompassing the successful integration of SACs into water purification processes needs to be *** review aims to accentuate recent trends by presenting the synthesis,structure,and environment and energy application-relevant properties of *** results show that a comprehensive and multi-perspective summary of the advantages of SACs in environmental remediation can have significant benefits,such as fast kinetics,costeffectiveness,*** oxidation and reduction processes of SACs and functional SACs materials in water purification were ***,the last section is devoted to the current research gaps and further perspectives on the application of SACs in water treatment,which are summarized and analyzed.

关键词： Single-atom catalysis Water treatment Oxidation Reduction

Copper coordination-driven self-assembly and encapsulation of PCR reagents

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Chinese Chemical Letters 2024年第3期35卷 189-192页

作者： Chang Lu Jinkai zheng Juewen liu Institute of Food Science and Technology Chinese Academy of Agricultural SciencesBeijing 100193China Department of Chemistry Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooONN2L 3G1Canada

Polymerase chain reactions(PCR)are a very important tool for use in cloning,nucleic acid sequencing and diagnostic *** storage conditions of PCR reagents are limited to freezing and a lot of mixing steps are *** this paper,we report using metal ions to form coordination nanomaterials with the intrinsic components of the PCR reagents including dNTP,DNA primers and DNA polymerase as an integrated PCR reaction *** complete PCR reactions,users need only to dissolve the coordination nanomaterials with a buffer and add template DNA.A few transition metal ions were screened and Cu^(2+)was found to be the most effective metal ion for this *** the encapsulation efficiency of PCR reagents was measured,which can reach close to 100%for the primers and DNA polymerase,but only 10%for dNTP because dNTP was *** study also exhibited this integrated PCR reaction system can be used for DNA detection with a similar detection limit to the normal PCR,and showed good stability of encapsulated PCR nanomaterial after storage for a week.

关键词： Metal ions Coordination Encapsulation PCR Storage

Dysregulated N6-methyladenosine modification in peripheral immune cells contributes to the pathogenesis of amyotrophic lateral sclerosis

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Frontiers of Medicine 2024年第2期18卷 285-302页

作者： Di He Xunzhe Yang Liyang liu Dongchao Shen Qing liu Mingsheng liu xue Zhang Liying Cui Department of Neurology Peking Union Medical College Hospital(PUMCH)Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100730China Medical Doctor Program Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing100730China McKusick-Zhang Center for Genetic Medicine State Key Laboratory of Medical Molecular BiologyInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic MedicinePeking Union Medical CollegeBeijing100730China Neuroscience Center Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100730China

Amyotrophic lateral sclerosis(ALS)is a progressive neurogenerative disorder with uncertain *** evidence implicates N6-methyladenosine(m6A)modification in ALS *** RNA immunoprecipitation sequencing(MeRIP-seq)and liquid chromatography–mass spectrometry were utilized for m6A profiling in peripheral immune cells and serum proteome analysis,respectively,in patients with ALS(n=16)and controls(n=6).The single-cell transcriptomic dataset(GSE174332)of primary motor cortex was further analyzed to illuminate the biological implications of differentially methylated genes and cell communication *** of peripheral immune cells revealed extensive RNA hypermethylation,highlighting candidate genes with differential m6A modification and expression,including C-X3-C motif chemokine receptor 1(CX3CR1).In RAW264.7 macrophages,disrupted CX3CR1 signaling affected chemotaxis,potentially influencing immune cell migration in *** proteome analysis demonstrated the role of dysregulated immune cell migration in *** type-specific expression variations of these genes in the central nervous system(CNS),particularly microglia,were *** communication between neurons and glial cells was selectively altered in ALS *** integrated approach underscores m6A dysregulation in immune cells as a potential ALS contributor.

关键词： amyotrophic lateral sclerosis N^(6)-methyladenosine epi-transcriptome proteome single cell RNA sequencing analysis CX3CR1

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 *** a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury ***,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord *** 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 ***,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 *** 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 ***,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 ***-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

Effects of dynamical spanwise retraction and stretch on flapping-wing forward flights

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Chinese Journal of Aeronautics 2024年第4期37卷 181-202页

作者： Kang liu Bifeng SONG Ang CHEN Zhihe WANG Dong xue Wenqing YANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Intelligent Aircraft Research Center Chengdu Technological UniversityChengdu 610031China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China Harbin Institute of Technology Shenzhen 518055China

Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation into the aerodynamic effects of such bio-inspired concept in forward flights has been performed based on a three-dimensional wing in plunging motion and a twosection wing in flapping motion. The currently considered Reynolds number and Strouhal number are Re=1.5×10^(5) and St=0.3, respectively. During the research, the mean angle of attack is varied in relatively wide ranges to achieve lift-thrust interconversion for the wings. The conclusive results show that dynamical spanwise retraction and stretch has induced three absolutely desirable scenarios for the oscillating wings in forward flights, namely producing more lift and consuming less power for a given thrust generation, producing more thrust and consuming less power for a given lift generation, and producing more lift and more thrust while consuming less power. Furthermore,the morphing wings have alleviated periodical aerodynamic load fluctuations compared with the non-morphing baseline. The mechanism of the aerodynamic effects of the bionic morphing mode is analyzed with the aid of field visualization. The current article is the first to reveal the absolute advantages of the bionic spanwise morphing. Hopefully, it may help comprehend the behaviors of natural fliers and provide inspirations for performance enhancement of micro artificial flappingwing vehicles.

关键词： Flapping wing Morphing wing Bionic Aerodynamics Vortex Flight

High-throughput calculation-based rational design of Fe-doped MoS_(2) nanosheets for electrocatalytic p H-universal overall water splitting

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Journal of Energy Chemistry 2024年第4期91卷 194-202页

作者： Guangtong Hai Xiangdong xue Zhenyu Wu Canyang Zhang Xin liu Xiubing Huang Institute of Zhejiang University-Quzhou Zhejiang UniversityQuzhou 324000ZhejiangChina Beijing Key Laboratory of Membrane Materials and Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory of Function Materials for Molecule&Structure ConstructionSchool of Materials Science and EngineeringUniversity of Science and TechnologyBeijing 100083China CentreÉnergie Matériaux et Télécommunications(EMT) Institut national de la recherche scientifique(INRS)Varennes J3X1P7QuébecCanada

Electrocatalytic water splitting is crucial for H2generation via hydrogen evolution reaction(HER)but subject to the sluggish dynamics of oxygen evolution reaction(OER).In this work,single Fe atomdoped MoS_(2)nanosheets(SFe-DMNs)were prepared based on the high-throughput density functional theory(DFT)calculation *** to the synergistic effect between Fe atom and MoS_(2)and optimized intermediate binding energy,the SFe-DMNs could deliver outstanding activity for both HER and *** assembled into a two-electrode electrolytic cell,the SFe-DMNs could achieve the current density of 50 mA cm^(-2)at a low cell voltage of 1.55 V under neutral *** results not only confirmed the effectiveness of high-throughput screening,but also revealed the excellent activity and thus the potential applications in fuel cells of SFe-DMNs.

关键词： High-throughput calculation Overall water splitting Single atom doped catalyst Molybdenum disulfide nanosheet

Self-Powered Flexible Multicolor Electrochromic Devices for Information Displays

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Research 2024年第2期2023卷 529-540页

作者： Wenzhao xue Yun Zhang Feng liu Yao Dou Mei Yan Wenshou Wang School of Chemistry and Chemical Engineering University of JinanJinan 250022P.R.China

The development of self-powered flexible multicolor electrochromic(EC)systems that could switch different color without an external power supply has remained extremely ***,a new trilayer film structure for achieving self-powered flexible multicolor EC displays based on self-charging/discharging mechanism is proposed,which is simply assembled by sandwiching an ionic gel film between 2 cathodic nickel hexacyanoferrate(NiHCF)and Prussian blue(PB)nanoparticle films on indium tin oxide *** display exhibits independent self-powered color switching of NiHCF and PB films with fast responsive time and high reversibility by selectively connecting the Al wire as anodes with the 2 EC *** switching is thus achieved through a color overlay effect by superimposing the 2 EC films,including green,blue,yellow,and *** bleaching/coloration process of the displays is driven by the discharging/self-charging mechanism for NiHCF and PB films,respectively,ensuring the self-powered color switching of the displays reversibly without an external power *** is further demonstrated that patterns can be easily created in the self-powered EC displays by the spray-coating method,allowing multicolor changing to convey specific ***,a self-powered ionic writing board is demonstrated based on the self-powered EC displays that can be repeatedly written freehand without the need of an external power *** believe that the design concept may provide new insights into the development of self-powered flexible multicolor EC displays with self-recovered energy for widespread applications.

关键词： connecting repeatedly powered

Network Pharmacology Based Elucidation of Molecular Mechanisms of Laoke Formula for Treatment of Advanced Non-Small Cell Lung Cancer

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Chinese Journal of Integrative Medicine 2024年第11期30卷 984-992页

作者： FENG Yu-yu liu Jin-feng xue Yang liu Dan WU Xiong-zhi Department of Nursing Tangshan Vocational and Technical College School of Chinese Materia Medica Tianjin University of Traditional Chinese Medicine Department of Oncology Tianjin Medical University General Hospital Tianjin Medical University Cancer Institute and Hospital National Clinical Research Center for Cancer Key Laboratory of Cancer Prevention and Therapy Tianjin's Clinical Research Center for China Tianjin Nankai Hospital Tianjin Medical University

Objective: To explore the specific pharmacological molecular mechanisms of Laoke Formula(LK)on treating advanced non-small cell lung cancer(NSCLC) based on clinical application, network pharmacology and experimental validation. Methods: Kaplan-Meier method and Cox regression analysis were used to evaluate the survival benefit of Chinese medicine(CM) treatment in 296 patients with NSCLC in Tianjin Medical University Cancer Institute and Hospital from January 2011 to December 2015. The compounds of LK were screened using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, and the corresponding targets were performed from Swiss Target Prediction. NSCLC-related targets were obtained from Therapeutic Target Database and Comparative Toxicogenomics Database. Key compounds and targets were identified from the compound-target-disease network and protein-protein interaction(PPI) network analysis, respectively. Kyoto Encyclopedia of Genes and Genomes(KEGG) and Gene Ontology(GO) enrichment analysis were used to predict the potential signaling pathways involved in the treatment of advanced NSCLC with LK. The binding affinities between key ingredients and targets were further verified using molecular docking. Finally, A549 cell proliferation and migration assay were used to evaluate the antitumor activity of LK. Western blot was used to further verify the expression of key target proteins related to the predicted pathways. Results: Kaplan-Meier survival analysis showed that the overall survival of the CM group was longer than that of the non-CM group(36 months vs.26 months), and COX regression analysis showed that LK treatment was an independent favorable prognostic factor(P=0.027). Next, 97 components and 86 potential targets were included in the network pharmacology, KEGG and GO analyses, and the results indicated that LK was associated with proliferation and apoptosis. Moreover,molecular docking revealed a good binding affinity between the key

关键词： Chinese medicine LaoKe Formula anti-tumor network pharmacology non-small cell lung cancer