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A novel flexible nerve guidance conduit promotes nerve regeneration while providing excellent mechanical properties

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Neural Regeneration Research 2025年第7期20卷 2084-2094页

作者： Tong li Quhan Cheng Jingai Zhang Boxin liu Yu shi Haoxue Wang lijie Huang Su Zhang Ruixin Zhang Song Wang guangxu lu Peifu Tang Zhongyang liu Kai Wang Department of Orthopedics the Fourth Medical Center of Chinese PLA General HospitalBeijingChina Department of Training and Sports Medicine Characteristic Medical Center of Chinese People’s Armed Police ForceTianjinChina Medical School of Chinese PlA BeijingChina Key laboratory of Bioactive Materials for the Ministry of Education College of Life SciencesNankai UniversityTianjinChina Department of Orthopedics Tianjin HospitalTianjinChina Department of Rehabilitation Medicine Er Quan Hospital of PAPWuxiJiangsu ProvinceChina

Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor *** an alternative,nerve guidance conduits may be *** ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve *** designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align ***,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber *** presence of aligned fibers on the inner surface can promote the extension of nerve cells along the *** helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide *** novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.

关键词： aligned fibers anti-kinking helical fibers nerve guidance conduit nerve regeneration peripheral nerve injury topological guidance

Hua's Theorem on Five Almost Equal Prime Squares

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Acta Mathematica Sinica,English Series 2006年第3期22卷 907-916页

作者： guang shi l Department of Mathematics Shandong University

In this paper we sharpen Hua＇s result by proving that each sufficiently large integer N congruent to 5 modulo 24 can be written as N=p1^2＋p2^2＋p3^2＋p4^2＋p5^2,with │pj-√N/5│≤U=N^1/2-1/28＋ε,where pj are primes.

关键词： Additive theory of prime numbers Circle method iterative method

Healing Process of Casting Pores in a Ni-based Superalloy by Hot Isostatic Pressing

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Journal of Materials Science & Technology 2015年第11期31卷 1151-1157页

作者： X.g.Zheng Y.-N.shi l.H.lou Shenyang National laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Superalloy Division Institute of Metal Research Chinese Academy of Sciences

Hot isostatic pressing （HIP） with a pressure of 180 MPa at a temperature of 1170 ℃ was introduced to an investment cast Ni-based superalloy （Mgl） turbocharger blade to explore the healing process of casting pores generated during investment casting. Optical micrograph and scanning electron naicroscopy （SEM） observations indicate that eutectic pores are the main cast defects in the as-cast blade before HIP. These pores normally locate at the solidification front of γ/γ＇ eutectic with a size of a few micrometers to a few tens of micrometers. After HIP for 4 h, most of the pores were closed. Based on phase characteristics, these pores were healed by the formation of γ matrix with finer and irregular-shaped γ＇ precipitates. Healing interface can be easily distinguished by SEM. line scan by using energy dispersive X-ray spectroscopy （EDS） reveals a much higher Ti and Al concentration in the healing interface. It is proposed that solute diffusion toward the casting pores during HIP results in the formation of γ, and the much higher concentration of γ＇-forming elements Al and Ti near the healing interface contributes to the precipitation of γ＇ in the healed region in the succeeding cooling process after HIP.

关键词： Superalloy Hot isostatic pressing (HIP) Healing

Metabolome and RNA-seq reveal discrepant metabolism and secretory metabolism profile in skeletal muscle between obese and lean pigs at different ages

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Science China life Sciences 2025年

作者： liu guo Junfei Xu Wenyue Zhou Sisi Chen Hanjing shi Mengmeng Han Zekun Yang Yehui Duan Weijun Pang Yulong Yin Fengna li laboratory of Animal Nutritional Physiology and Metabolic Process Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences University of Chinese Academy of Sciences laboratory of Animal Fat Deposition and Muscle Development College of Animal Science and Technology Northwest A&F University College of Advanced Agricultural Sciences University of Chinese Academy of Sciences

Metabolites and metabolism-related gene expression profiles in skeletal muscle change dramatically under obesity, aging and metabolic disease. Since obese and lean pigs are ideal models for metabolic research. Here, we compared metabolome and transcriptome of longissimus dorsi(lD) muscle between Taoyuan black(TB, obese) and Duroc(lean) pigs at different ages. We defined the “window phase” of intramuscular fat(IMF) deposition in TB pig, which has significantly higher IMF than Duroc pig. Our results displayed discrepant lipid composition and different expression genes(DEgs) enriched in lipid metabolism, and both metabolome and transcriptome analyses revealed stronger energy expenditure and more active amino acid and protein metabolism in Duroc pig. 10 up-and 51 down-regulated biomarker metabolites with age-and breed-specificity were identified. Potential secretory metabolites, including organic acid(fumaric acid, succinate,malic acid, and gamma-aminobutyric acid), amino acid(l-lysine, and l-glutamic acid), lipid(2-hydroxyisovaleric acid, and l-carnitine) were demonstrated a significant correlation with IMF deposition. Our research highlights the huge difference of metabolic spectrum in skeletal muscle between obese and lean model and muscle-derived secretory metabolites might act as an ambassador of intercellular communication to regulate systematic metabolism.

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Cobalamin-dependent radical S-adenosyl-l-methionine protein functions with a partner to successively methylate tricyclic indole alkaloid for chuangxinmycin maturation and derivatization

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Science China Chemistry 2025年第1期 308-316页

作者： Sili Wang Jiancheng Huang Yanan Du Wei Huang Yufeng Xue Xiaokun Xu guannan Zhong Yuanyuan shi Bin Hong Xiaoying Bian Wen liu State Key laboratory of Chemical Biology Shanghai Institute of Organic Chemistry University of Chinese Academy of SciencesChinese Academy of Sciences State Key laboratory of Microbial Technology Shandong University National Health Commission (NHC) Key laboratory of Biotechnology for Microbial Drugs Institute of Medicinal BiotechnologyChinese Academy of Medical Science & Peking Union Medical College

Cobalamin(Cbl)-dependent radical S-adenosyl-l-methionine(SAM) proteins constitute the largest collection of the radical SAM superfamily that has hundreds of thousands of individual members. Many of these proteins are involved in the biosynthesis of pharmaceutically important natural products to catalyze chemically demanding reactions. In the biosynthetic pathway of chuangxinmycin(CXM), a unique indole alkaloid antibiotic with potent anti-infective activity, functionalization of the characteristic thiopyrano[4,3,2-cd]indole scaffold by regio-and stereoselective C3-methylation is believed to rely on a Cbl-dependent radical process, which, however, remained to be reconstituted biochemically. We here report the dissection of this enzymatic process, which requires the incorporation of Cxm8, a Cbl-dependent radical SAM protein, with Cxm9, a DUF5825family protein that shares no homology to any proteins of known functions. Cxm8 and Cxm9 function together by forming an unexpected heterodimeric complex that selectively catalyzes C3-methylation of the tricyclic indole-S-hetero ring system in a successive manner, achieving CXM and a recently identified, C3-dimethylated congener. Detailed biochemical characterization,isotope labeling, structural simulation and bioinformatics analysis rationalized the catalysis of the Cxm8/Cxm9 complex and particularly the necessity of the DUF5825 protein for C3-methylase activity. This is the first example that a Cbl-dependent protein acts with a partner to exhibit radical SAM activity.

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Monotone Chains in Modulus of Two Classes of Dirichlet Coefficients

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Acta Mathematica Sinica,English Series 2023年第6期39卷 1101-1114页

作者： guang shi lü Qiang MA School of Mathematics Shandong UniversityJi'nan 250100P.R.China

let f1,...,fkand g1,...,qkbe non-CM newforms of square-free *** byλ_(sym)jf_(i)(n)the coefficients of the Dirichlet expansion of l(sym^(j)f_(i),s)andν1,...,νkthe distinct positive integers such thatλ_(sym)jf_(i)(νi)≠*** this paper,we obtain that there exist infinitely many positive integers m such that 0let expansion of l(sym^(j1)f×sym^(j2)g,s),we have a similar result.

关键词： Dirichlet coefficients Sato-Tate conjecture

Totally homogeneous networks

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National Science Review 2019年第5期6卷 962-969页

作者： Dinghua shi linyuan lü guanrong Chen Department of Mathematics College of Science Shanghai University Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Department of Electronic Engineering City University of Hong Kong

In network science, the non-homogeneity of node degrees has been a concerning issue for ***, with today’s modern web technologies, the traditional social communication topologies have evolved from node-central structures into online cycle-based communities, urgently requiring new network theories and *** the focus from node degrees to network cycles could reveal many interesting properties from the perspective of totally homogenous networks or sub-networks in a complex network, especially basic simplexes(cliques) such as links and ***, compared with node degrees, it is much more challenging to deal with network *** studying the latter, a new clique vector-space framework is introduced in this paper, where the vector space with a basis consisting of links has a dimension equal to the number of links, that with a basis consisting of triangles has the dimension equal to the number of triangles and so *** two vector spaces are related through a boundary operator, for example mapping the boundary of a triangle in one space to the sum of three links in the other *** the new framework,some important concepts and methodologies from algebraic topology, such as characteristic number,homology group and Betti number, will play a part in network science leading to foreseeable new research *** immediate applications, the paper illustrates some important characteristics affecting the collective behaviors of complex networks, some new cycle-dependent importance indexes of nodes and implications for network synchronization and brain-network analysis.

关键词： boundary operator clique vector space cycle homology group totally homogenous network

MICROSTRUCTURE AND PROPERTIES OF Zl201 AllOY OBTAINED BY NEAR-lIQUIDUS ElECTROMAgNETIC CASTINg

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Acta Metallurgica Sinica(English letters) 2005年第5期18卷 653-658页

作者： P. Wang l.F. shi g.M. lu J.Z. Cui The Key laboratory of Electromagnetic Processing of Material Ministry of Education Northeastern University Shenyang 110004 China

The microstructures of Zl201 alloy slurry prepared by near-liquidus electromagnetic casting （NlEMC）, electromagnetic casting（EMC）, and near-liquidus casting（NlC） were investigated by means of electron microscopy and image analysis. Mechanical properties of as-cast alloys were determined. The results show that the NlEMC induces a fine, uniform, and equiaxed grain structure with a mean equal-area-circle grain diameter of 32.8μm. The as-cast aUoy has a hardness of HV122.8 and a tensite strength of 368MPa. Both of them are betterthan those of the alloys prepared by EMC and by NlC. The mechanism of grain refinement in the NlEMC alloy slurry was discussed.

关键词： near-liquidus casting electromagnetic casting rheocasting,microstructure property

Formability of Materials with Small Tools in Incremental Forming

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Chinese Journal of Mechanical Engineering 2020年第4期33卷 150-158页

作者： Hongyu Wei g.Hussain X.shi B.B.l Isidore Mohammed Alkahtani Mustufa Haider Abidi College Mechanical&Electrical Engineering Nanjing University of Aeronautics&AstronauticsNanjingPeople’s Republic of China Faculty of Mechanical Engineering GIK Institute of Engineering Sciences&TechnologyTopi 23460Pakistan College of Mechanical Engineering Shanghai University of Engineering ScienceShanghaiPeople’s Republic of China Bradenburg University of Technology CottbusGermany Industrial Engineering Department College of EngineeringKing Saud UniversityRiyadh 11421Saudi Arabia Advanced Manufacturing Institute King Saud UniversityRiyadh 11421Saudi Arabia

Single point incremental forming(SPIF)is an innovative sheet forming process with a high economic *** formability in this process can be maximized by executing forming with a tool of specific small radius,regarded as threshold critical *** value has been reported as 2.2 mm for 1 mm thick sheet ***,with a change in the forming conditions specifically in the sheet thickness and step size,the critical radius is likely to alter due to a change in the bending *** main aim of the present study is to undertake this point into account and develop a relatively generic *** study is composed of experimental and numerical *** maximum wall angle(θmax)without sheet fracturing is regarded as sheet formability.A number of sheet materials are formed to fracture and the trends correlating formability with normalized radius(i.e.,R/To where R is the tool-radius and To is the sheet thickness)are *** trends confirm that there is a critical tool-radius(Rc)that maximizes the formability in ***,it is found that the critical radius is not fixed rather it shows dependence on the sheet thickness such that Rc=βTo,whereβvaries from 2.2 to 3.3 as the thickness increases from 1 mm to 3 *** critical radius,however,remains insensitive to variation in step size ranging from 0.3 mm to 0.7 *** is also observed that the selection of tool with Rlity window not only on the higher side but also on the lower *** higher limit,as revealed by the experimental and FEA results,diminishes due to excessive shearing because of in-plane biaxial compression,and the lower limit reduces due to pillowing in the bottom of *** new tool-radius condition proposed herein study would be helpful in maximizing the formability of materials in SPIF without performing experimental trials.

关键词： Incremental forming Critical tool-radius Formability curve Finite element analysis