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A Fermi-LAT Study of Globular Cluster Dynamical Evolution in the Milky Way:Millisecond Pulsars as the Probe

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Research in Astronomy and Astrophysics 2024年第2期24卷 1-23页

作者： li feng Zhongqun Cheng Wei Wang Zhiyuan li Yang Chen School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Department of Astronomy School of Physics and TechnologyWuhan UniversityWuhan 430072China WHU-NAOC Joint Center for Astronomy Wuhan UniversityWuhan 430072China Key Laboratory of Modern Astronomy and Astrophysics Nanjing UniversityNanjing 210023China

Using archival Fermi-LAT data with a time span of~12 yr,we study the population of Millisecond Pulsars(MSPs)in Globular Clusters(GlCs)and investigate their dependence on cluster dynamical evolution in the Milky Way.We show that theγ-ray luminosity(L_(γ))and emissivity(i.e.,ε_(γ)=L_(γ)/M,with M the cluster mass)are good indicators of the population and abundance of MSPs in GlCs,and they are highly dependent on the dynamical evolution history of the host clusters.Specifically speaking,the dynamically older GlCs with more compact structures are more likely to have larger L_(γ)andε_(γ),and these trends can be summarized as strong correlations with cluster stellar encounter rateΓand the specific encounter rate(Λ=Γ/M),with L_(γ)∝Γ^(0.7±0.11)andε_(γ)∝Λ^(0.73±0.13)for dynamically normal GlCs.However,as GlCs evolve into deep core collapse,these trends are found to be reversed,implying that strong encounters may have lead to the disruption of Low-Mass X-ray Binaries and ejection of MSPs from core-collapsed systems.Besides,the GlCs are found to exhibit largerε_(γ)with increasing stellar mass function slope(ε_(γ)∝10^((0.52±0.1)α)),decreasing tidal radius(ε_(γ)∝R_(t)^(-10±0.22))and distances from the Galactic Center(GC,ε_(γ)∝R_(gc)^(-1.13±0.21)).These correlations indicate that,as GlCs losing kinetic energy and spiral in toward the GC,tidal stripping and mass segregation have a preference in leading to the loss of normal stars from GlCs,while MSPs are more likely to concentrate to cluster center and be deposited into the GC.Moreover,we gaugeε_(γ)of GlCs is~10-1000 times larger than the Galactic bulge,the latter is thought to reside thousands of unresolved MSPs and may be responsible for the GC 7-ray excess,which supports that GlCs are generous contributors to the population of MSPs in the GC.

关键词： (Galaxy:)globular clusters general-(stars:)pulsars general-Galaxy kinematics and dynamics-Galaxy center-Galaxy bulge-gamma-rays stars-gamma-rays diffuse background-gamma-rays galaxies

Discovery of a potent and highly selective inhibitor of SIRT6 against pancreatic cancer metastasis in vivo

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Acta Pharmaceutica Sinica B 2024年第3期14卷 1302-1316页

作者： Xinyuan Xu Qian Zhang Xufeng Wang Jing Jin Chengwei Wu li feng Xiuyan Yang Mingzhu Zhao Yingyi Chen Shaoyong Lu Zhen Zheng Xiaobing Lan Yi Wang Yan Zheng Xuefeng Lu Qiufen Zhang Jian Zhang State Key Laboratory of Medical Genomics National Research Center for Translational Medicine at ShanghaiRuijin HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China Medicinal Chemistry and BioinformaticsCenter Shanghai Jiao Tong University School of MedicineShanghai 200025China Department of General Surgery Huashan HospitalCancer Metastasis InstituteFudan UniversityShanghai 200040China Institute of Immunology and the CAS Key Laboratory of Innate Immunity and Chronic Disease School of Basic Medicine and Medical CenterUniversity of Science and Technology of ChinaHefei 230026China Department of Assisted Reproduction Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai 200011China College of Pharmacy Ningxia Medical UniversityYinchuan 750004China Department of Pancreatic Surgery Shanghai General HospitalShanghai Key Laboratory of Pancreatic DiseaseInstitute of Pancreatic DiseaseShanghai Jiao Tong University School of MedicineShanghai 200080China

Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be a potential target for antimetastasis of pancreatic cancer.However,highly selective and potency SIRT6 inhibitor that can be used in vivo is yet to be discovered.Here,we developed a noveSIRT6 allosteric inhibitor,compound 11e,with maximal inhibitory potency and an IC_(50) value of 0.98±0.13μmol/L.Moreover,compound 11e exhibited significant selectivity against other histone deacetylases(HADC1-11 and SIRT1-3)at concentrations up to 100μmol/L.The allosteric site and the molecular mechanism of inhibition were extensively elucidated by cocrystal complex structure and dynamic structural analyses.Importantly,we confirmed the antimetastatic function of such inhibitors in four pancreatic cancer cell lines as well as in two mouse models of pancreatic cancer liver metastasis.To our knowledge,this is the first study to reveal the in vivo effects of SIRT6 inhibitors on liver metastatic pancreatic cancer.It not only provides a promising lead compound for subsequent inhibitor developmentargeting SIRT6 but also provides a potential approach to address the challenge of metastasis in pancreatic cancer.

关键词： SIRT6 Inhibitor Allosteric Selectivity Cocrystal Pancreatic cancer metastasis

Impacts of pancreatic exocrine insufficiency on gut microbiota

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第4期25卷 271-279页

作者： Yulin GUO feng CAO Fei li Department of General Surgery Xuanwu Hospital of Capital Medical UniversityBeijing 100053China Acute Pancreatitis Clinical Center of Capital Medical University Beijing 100053China

Pancreatic exocrine insufficiency(PEI)can be induced by various kinds of diseases,including chronic pancreatitis,acute pancreatitis,and post-pancreatectomy.The main pathogenetic mechanism of PEI involves the decline of trypsin synthesis,disorder of pancreatic fluid flow,and imbalance of secretion feedback.Animal studies have shown that PEI could induce gut bacterial overgrowth and dysbiosis,with the abundance of Lactobacillus and Bifidobacterium increasing the most,which could be partially reversed by pancreatic enzyme replacement therapy.Clinical studies have also confirmed the association between PEI and the dysbiosis of gut microbiota.Pancreatic exocrine secretions and changes in duodenal p H as well as bile salt malabsorption brought about by PEI may affect and shape the abundance and composition of gut microbiota.In turn,the gut microbiota may impact the pancreatic exocrine acinus through potential bidirectional crosstalk.Going forward,more and higher-quality studies are needed that focus on the mechanism underlying the impact of PEI on the gut microbiota.

关键词： Pancreatic exocrine insufficiency Gut microbiota Gut microbiome Pancreatic enzyme replacement therapy

Honokiol Prevents Intestinal Barrier Dysfunction in Mice with Severe Acute Pancreatitis and Inhibits JAK/STAT1 Pathway and Acetylation of HMGB1

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Chinese Journal of Integrative Medicine 2024年第6期30卷 534-542页

作者： li Jie CHEN Ya-feng GAO Lei li Yi-jie feng Dian-xu Department of General Surgery Putuo HospitalShanghai University of Traditional Chinese MedicineShanghai200062China

Objective To investigate the effect of honokiol(HON)and the role of high-mobility group protein B1(HMGB1)on the pathogenesis of severe acute pancreatitis(SAP).Methods Thirty mice were numbered according to weight,and randomly divided into 5 groups using a random number table,including control,SAP,SAP and normal saline(SAP+NS),SAP and ethyl pyruvate(SAP+EP),or SAP+HON groups,6 mice in each group.Samples of pancreas,intestine,and blood were collected 12 h after SAP model induction for examination of pathologic changes,immune function alterations by enzyme linked immunosorbent assay(EliSA),and Western blot.In vitro experiments,macrophages were divided into 5 groups,the control,lipopolysaccharide(LPS),LPS+DMSO(DMSO),LPS+anti-HMGB1 monoclonal antibody(mAb),and LPS+HON groups.The tight connection level was determined by transmission electron microscopy and fluorescein isothiocyanate-labeled.The location and acetylation of HMGB1 were measured by Western blot.Finally,pyridone 6 and silencing signal transducer and activator of the transcription 1(siSTAT1)combined with honokiol were added to determine whether the Janus kinase(JAK)/STAT1 participated in the regulation of honokiol on HMGB1.The protein expression levels of HMGB1,JAK,and STAT1 were detected using Western blot.Results Mice with SAP had inflammatory injury in the pancreas,bleeding of intestinal tissues,and cells with disrupted histology.Mice in the SAP+HON group had significantly fewer pathological changes.Mice with SAP also had significant increases in the serum levels of amylase,lipase,HMGB1,tumor necrosis factor-α,interleukin-6,diamine oxidase,endotoxin-1,and procalcitonin.Mice in the SAP+HON group did not show these abnormalities(Plity,decreased the levels of junctional adhesion molecule C,and elevated intercellular permeability(P<0.01).HON treatment blocked these effects.Studies of macrophages indicated that LPS led to low nucle

关键词： severe acute pancreatitis intestinal barrier dysfunction honokiol high-mobility group protein B1 Januskinase signal transducerand activatorof transcription1

Higher-order expansions of powered extremes of logarithmic general error distribution

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 47-54页

作者： TAN Xiao-feng li li-hui School of Mathematics and Statistics Southwest UniversityChongqing 400715China

In this paper,Let M_(n)denote the maximum of logarithmic general error distribution with parameter v≥1.Higher-order expansions for distributions of powered extremes M_(n)^(p)are derived under an optimal choice of normalizing constants.It is shown that M_(n)^(p),when v=1,converges to the Frechet extreme value distribution at the rate of 1/n,and if v>1 then M_(n)^(p)converges to the Gumbel extreme value distribution at the rate of(loglogn)^(2)=(log n)^(1-1/v).

关键词： logarithmic general error distribution convergence rate higher-order expansion powered ex-treme

Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： Wei lin Yechun Ding Yongsheng Wang Peng li Yanpeng Zhang feng Yun feng li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark Center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State lighting Engineering Research Center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean geometry.We report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space curvature.While the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic orbits.These observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space

Effect of Sc on Al_(3)Fe phase and mechanical properties of as-cast AA5052 aluminum alloy

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China Foundry 2024年第3期21卷 257-264页

作者： Yang li Qing Yu feng-feng Chen Jia-wen He Hong-mei Yang Meng-nie li Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China

The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical properties.Previous studies have demonstrated that the addition of Sc to aluminum alloys can improve both the microstructure and properties of the alloys.In this study,the effect of Sc on the Fe-rich phase and properties of the AA5052 aluminum alloy was studied by adding 0%,0.05%,0.2%,and 0.3%Sc.The results show that with the increase of Sc,the coarse needle-like Fe-rich phase gradually transforms into Chinese-script and then nearly spherical particles,reduce the size of Fe-rich phase,and refine the grain with increase of high angle grain boundaries(HAGBs).These microstructure changes enhance the strength of the AA5052 alloy through Sc addition.The ductility of the alloy is obviously improved because the addition of a lower amount of Sc changes the morphology of Fe-rich phase from needle-like into a Chinese-script,and it is subsequently reduced as a result of significant increase in HAGBs with increasing Sc content.

关键词： AA5052 aluminum alloy Al3Fe phase mechanical properties grain boundary

Polyethylenimine-modified graphene quantum dots promote endothelial cell proliferation

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Regenerative Biomaterials 2024年第2期3卷 137-146页

作者： Qirong Xu Chen li Xiangyan Meng Xinghong Duo Yakai feng School of Chemistry and Chemical Engineering Qinghai University for NationalitiesXining 810007PR China Key Laboratory of National Ethnic Affairs Commission of Resource Chemistry and Ecological Environment Protection on Qinghai-Tibet Plateau Xining 810007PR China institute of Disaster and Emergency Medicine Tianjin UniversityTianjin 300072PR China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350PR China Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjin 300072PR China

Endothelial cell proliferation plays an important role in angiogenesis and treatment of related diseases.The aim of this study was to evaluate the effect of polyethylenimine(PEI)-modified graphene quantum dots(GQDs)gene vectors on endothelial cell prolifera-tion.The GQDs-cationic polymer gene vectors were synthesized by amidation reaction,and used to deliver pzNF580 gene to Human umbilical vein endothelial cells(HUVECs)for promoting their proliferation.The chemical modification of GQDs can ad-just gene vectors'surface properties and charge distribution,thereby enhancing their interaction with gene molecules,which could effectively compress the pZNF580 gene.The CCK-8 assay showed that the cell viability was higher than 80%at higher vector concentration(40μg/mL),demonstrating that the GQDs-cationic polymer gene vectors and their gene complex nanoparticles(NPs)having low cytotoxicity.The results of the live/dead cell double staining assay were consistent with those of the CCK-8 assay,in which the cell viability of the A-GQDs/pZNF580(94.38±6.39%),C-GQDs-PEI-polylactic acid-co-polyacetic acid(PLGA)/pZNF580(98.65±6.60%)and N-GQDs-PEI-PLGA/pZNF580(90.08±1.60%)groups was significantly higher than that of the lipofectamine 2000/pzNF580(71.98±3.53%)positive treatment group.The results of transfection and western blot experiments showed that the vector significantly enhanced the delivery of plasmid to HUVECs and increased the expression of pZNF580 in HUVECs.In addition,the gene NPs better promote endothelial cell migration and proliferation.The cell migration rate and proliferation ability of C-GQDs-PEI-PLGA/pZNF580 and N-GQDs-PEI-PLGA/pZNF580 treatment groupS were higher than those of lipofectamine 2000/pDNA treatment group.Modified GQDs possess the potential to serve as efficient gene carriers.They tightly bind gene molecules through charge and other non-covalent interactions,significantly improving the effciency of gene delivery and ensuring the smooth release of genes within the cell.This innovative strategy provides a

关键词： graphene quantum dots polyethylenimine ZNF580 gene endothelial cell proliferation

Exceptional points enhance sensing in silicon micromechanical resonators

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Microsystems & Nanoengineering 2024年第1期10卷 17-25页

作者： Man-Na Zhang Lei Dong li-feng Wang Qing-An Huang Key Laboratory of MEMS of the Ministry of Education Southeast UniversityNanjing 210096China

Exceptional points(EPs)have recently emerged as a new method for engineering the response of open physical systems,that is,systems that interact with the environment.The systems at the EPs exhibit a strong response to a small perturbation.Here,we show a method by which the sensitivity of silicon resonant sensors can be enhanced when operated at EPs.In our experiments,we use a pair of mechanically coupled silicon micromechanical resonators constituting a parity-time(PT)-symmetric dimer.Small perturbations introduced on the mechanically coupled spring cause the frequency to split from the EPs into the PT-symmetric regime without broadening the two spectrum linewidths,and this frequency splitting scales with the square root of the perturbation strength.The overall signal-tonoise ratio is still greatly enhanced,although the measured noise spectral density of the EP sensing scheme has a slight increase comparable to the traditional counterpart.Our results pave the way for resonant sensors with ultrahigh sensitivity.

关键词： resonant symmetric points