期刊文献+
共找到570,616篇文章
< 1 2 250 >
每页显示 20 50 100
Linking starch particle physicochemical properties to functionality in medicinal plants:Insights from Polygonum multiflorum and Smilax glabra 被引量:1
1
作者 Nan Wang Lingling Wu +2 位作者 Yaya Su Haifeng Tang Hailong Yuan 《Chinese Chemical Letters》 2026年第1期487-491,共5页
This study investigates the properties of high-purity starches extracted from Polygonum multiflorum(PMS)and Smilax glabra(SGS).The starches were characterized by scanning electron microscopy,Fouriertransform infrared ... This study investigates the properties of high-purity starches extracted from Polygonum multiflorum(PMS)and Smilax glabra(SGS).The starches were characterized by scanning electron microscopy,Fouriertransform infrared spectroscopy,X-ray diffraction,high-performance anion-exchange chromatography,and differential scanning calorimetry.Significant differences were observed in their morphological,physicochemical,and functional properties.PMS had a smaller particle size(13.68 μm),irregular polygonal shape,A-type,lower water absorption(62.67 %),and higher oil absorption(51.17 %).In contrast,SGS exhibited larger particles(31.75 μm),a nearly spherical shape,B-type,higher crystallinity(50.66 %),and greater amylose content(21.54 %),with superior thermal stability,shear resistance,and gelatinization enthalpy.SGS also contained higher resistant starch(83.28 %) and longer average chain length(20.58 %),but showed lower solubility,swelling power,light transmittance,and freeze-thaw stability.The physicochemical properties differences in crystal pattern and particle morphology between PMS and SGS lead to distinct behaviors during in vitro digestion and fermentation.These findings highlight the potential of medicinal plant starches in functional ingredients and industrial processes. 展开更多
关键词 Starch particle Physicochemical properties Starch function Resistant starch Starch extraction
原文传递
Nickel-Catalyzed Borylation of Aryl Nonaflates for the Efficient Synthesis of Arylboronates via C—O Bond Functionalization
2
作者 Liang Yuan Gui Chao +3 位作者 Wang Wenwen Chu Xueqiang Xu Hao Shen Zhiliang 《有机化学》 北大核心 2026年第1期207-214,共8页
Nickel-catalyzed borylation of aryl nonaflates with B2pin2 could be realized,which proceeded effectively by means of C—O bond functionalization to afford a wide variety of valuable arylboronates in moderate to excell... Nickel-catalyzed borylation of aryl nonaflates with B2pin2 could be realized,which proceeded effectively by means of C—O bond functionalization to afford a wide variety of valuable arylboronates in moderate to excellent yields with good functionality compatibility.In addition,the gram-scale synthesis and the application of the approach in the late-stage elaboration of aryl nonaflate derived from pterostilbene could also be achieved. 展开更多
关键词 nickel catalysis BORYLATION aryl nonaflates arylboronates C-O bond functionalization
原文传递
A Benchmark Study of Density Functional Theory(DFT)Methods for Mo-Catalyzed Carbonyl Oxidative Addition
3
作者 Chen Zitong Wang Liwei +1 位作者 Shen Xiao Qi Xiaotian 《有机化学》 北大核心 2026年第2期507-514,共8页
In molybdenum chemistry,the oxidative addition of o-quinone or 1,2-dicarbonyl compounds to molybdenum has been widely used in Mo-catalyzed C—C bond construction.The carbonyl oxidative addition to Mo(0)or Mo(Ⅱ)is the... In molybdenum chemistry,the oxidative addition of o-quinone or 1,2-dicarbonyl compounds to molybdenum has been widely used in Mo-catalyzed C—C bond construction.The carbonyl oxidative addition to Mo(0)or Mo(Ⅱ)is the critical elementary reaction of molybdenum catalysis.However,the relevant density functional theory(DFT)studies are relatively scarce,especially regarding the rational selection of functionals.In this work,14 functionals were employed to investigate the Mo-catalyzed carbonyl oxidative addition step.A benchmark study was carried out to evaluate their performance in structure optimization and energy calculation.Analyses of mean absolute error(MAE)and mean squared error(MSE)indicated that the B3LYP-D3(BJ),TPSSh,and ωB97X-D functionals exhibited superior performance in structure optimization.Using the DLPNO-CCSD(T)functional as the reference,the M06,M06-L,and MN15-L functionals exhibited good performance for energy calculation based on the structures optimized using the B3LYP-D3(BJ)functional.In particular,MN15-L provided the best performance with the smallest MAE and MSE. 展开更多
关键词 molybdenum catalysis carbonyl oxidation addition density functional theory(DFT)calculation DFT benchmark study
原文传递
Functional characterization of OsLT9 in regulating rice leaf thickness
4
作者 Jian Wang Dagang Chen +9 位作者 Haifei Hu Yamei Ma Tifeng Yang Jie Guo Ke Chen Chanjuan Ye Juan Liu Xinqiao Zhou Chuanguang Liu Junliang Zhao 《Journal of Genetics and Genomics》 2026年第2期223-233,共11页
Leaf thickness in rice critically influences photosynthetic efficiency and yield,yet its genetic basis remains poorly understood,with few functional genes previously characterized.In this study,we employ a pangenome-w... Leaf thickness in rice critically influences photosynthetic efficiency and yield,yet its genetic basis remains poorly understood,with few functional genes previously characterized.In this study,we employ a pangenome-wide association study(Pan-GWAS)on 302 diverse rice accessions from southern China,identifying 49 quantitative trait loci(QTLs)associated with leaf thickness.The most significant locus,qLT9,is fine-mapped to a 79-kb region on chromosome 9.Transcriptomic and genomic sequence analyses identify LOC_Os09g33480,which encodes a protein belonging to Multiple Organellar RNA Editing Factor family,as the key candidate gene.Overexpression and complementation transgenic experiments confirm LOC_Os09g33480(OsLT9)as the functional gene underlying qLT9,demonstrating a 24-bp Indel in its promoter correlates with the expression levels and leaf thickness.Notably,OsLT9 overexpression lines show not only thicker leaf,but also significantly enhanced photosynthetic efficiency and grain yield,establishing a link between leaf thickness modulation and yield enhancement.Population genomic analyses indicate strong selection for OsLT9 during domestication and breeding,with modern cultivars favoring thick leaf haplotype of OsLT9.This study establishes OsLT9 as a key regulator controlling leaf thickness in rice,and provides a valuable genetic resource for molecular breeding of high-yielding rice through optimization of plant architecture. 展开更多
关键词 RICE Leaf thickness GWAS functional gene OsLT9
原文传递
Research Progress and Network Pharmacological Analysis of Single Herb Improvement of Functional Dyspepsia by Jineijin Shanzha(Galli Gigerii Endothelium Corneum and Crataegi Fructus)Traditional Chinese Medicine Patch
5
作者 Yingbing HE Tianbao ZHANG Quan SHI 《Medicinal Plant》 2026年第1期10-19,共10页
[Objectives]To investigate the efficacy and potential mechanism of the topical preparation Jineijin-Shanzha Patch(composed of Galli Gigerii Endothelium Corneum and Crataegi Fructus)in improving functional dyspepsia(FD... [Objectives]To investigate the efficacy and potential mechanism of the topical preparation Jineijin-Shanzha Patch(composed of Galli Gigerii Endothelium Corneum and Crataegi Fructus)in improving functional dyspepsia(FD)based on network pharmacology.[Methods]Firstly,we reviewed the existing research progress on each constituent drug of the Jineijin Shanzha Patch for FD improvement.Following this,identified overlapping genes were utilized to construct both a"Drug-Active Component-FD Target"network and a Protein-Protein Interaction(PPI)network specific to the patch.In addition,Gene Ontology(GO)analysis was carried out.[Results]We identified that the 13 herbs in the Jineijin Shanzha Patch are mainly used for food stagnation,qi stagnation,and spleen deficiency.Screening revealed 43 active patch components,1414 FD-related targets,and 284 shared targets between them.The PPI network analysis further identified the top 10 core targets from these shared targets.From the"Drug-Active Component-FD Target"network,we identified the core elements.These included the herbal components Vignae Semen(from Liushenqu),Crataegi Fructus,and Pseudostellariae Radix;the active components quercetin,genistein,and apigenin;and the key targets CASP3,BCL2,and CASP9.GO analysis of the 284 overlapping targets indicated that the Jineijin Shanzha Patch may exert its therapeutic effects via regulation of biological processes such as the response to lipopolysaccharide,response to bacterium-derived molecules,and regulation of the apoptotic signaling pathway.[Conclusions]The main active components of the Jineijin Shanzha Patch(quercetin,genistein,and apigenin)may improve FD by modulating signaling pathways such as the response to lipopolysaccharide,response to bacterium-derived molecules,and regulation of the apoptotic signaling pathway,thereby acting on key targets including CASP3,BCL2,and CASP9. 展开更多
关键词 Medicinal plant functional dyspepsia Action mechanism Network pharmacology
暂未订购
New functional metal-organic framework(MOF) based optical thermometer by the post-synthesis doping rare earth ions into MOF
6
作者 Ying Zhao Yin-Hang Chai +4 位作者 Meng-Meng Zhai Qin-Ying Jin Xiaoyan Lu Yi-Dan Qiao Lu-Fang Ma 《Chinese Chemical Letters》 2026年第1期644-649,共6页
Ln@MOFs by anchoring rare metal ions(Ln) into metal-organic frameworks(MOFs) are proved to have great potential in the field of luminescent molecular thermometer.Nevertheless,the current research indicated that the po... Ln@MOFs by anchoring rare metal ions(Ln) into metal-organic frameworks(MOFs) are proved to have great potential in the field of luminescent molecular thermometer.Nevertheless,the current research indicated that the poor structural stability and low sensitivity hindered their application scope.In this work,a new MOF Zn-450 luminescent thermometer with multiple emission fluorescence characteristics was synthesized by the combination of 3,3,5,5-biphenyl tetracarboxylic acid(H_(4)L) and Zn^(2+) ion under solvothermal conditions.Interestingly,a high relative sensitivity of 1.43 % K^(-1) was found within 80-300 K based on Zn-450.Subsequently,two high-sensitivity luminescent Ln@MOFs(Ln = Eu and Tb) were further fabricated by doping rare earth ions into Zn-450 based on the post-synthesis strategy.Among them,the Eu@Zn-450 demonstrates various luminous behaviors while achieving an increased relative sensitivity of 1.63 % K^(-1).In addition,the continuously visible red,pink,and purple luminescent emissions at the same temperature range were observed,suggesting that the Eu@Zn-450 could be utilized as a luminescent colorimetric molecular thermometer.Importantly,this work can present new possibilities for the development of rare earth-doped luminescence and its temperature sensing properties. 展开更多
关键词 MOFs Optical thermometer Post-synthesis functionalization Rare metal ions LED
原文传递
A radiomics approach for predicting gait freezing in Parkinson's disease based on resting-state functional magnetic resonance imaging indices:A cross-sectional study 被引量:1
7
作者 Miaoran Guo Hu Liu +6 位作者 Long Gao Hongmei Yu Yan Ren Yingmei Li Huaguang Yang Chenghao Cao Guoguang Fan 《Neural Regeneration Research》 2026年第4期1621-1627,共7页
Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indice... Freezing of gait is a significant and debilitating motor symptom often observed in individuals with Parkinson's disease.Resting-state functional magnetic resonance imaging,along with its multi-level feature indices,has provided a fresh perspective and valuable insight into the study of freezing of gait in Parkinson's disease.It has been revealed that Parkinson's disease is accompanied by widespread irregularities in inherent brain network activity.However,the effective integration of the multi-level indices of resting-state functional magnetic resonance imaging into clinical settings for the diagnosis of freezing of gait in Parkinson's disease remains a challenge.Although previous studies have demonstrated that radiomics can extract optimal features as biomarkers to identify or predict diseases,a knowledge gap still exists in the field of freezing of gait in Parkinson's disease.This cross-sectional study aimed to evaluate the ability of radiomics features based on multi-level indices of resting-state functional magnetic resonance imaging,along with clinical features,to distinguish between Parkinson's disease patients with and without freezing of gait.We recruited 28 patients with Parkinson's disease who had freezing of gait(15 men and 13 women,average age 63 years)and 30 patients with Parkinson's disease who had no freezing of gait(16 men and 14 women,average age 64 years).Magnetic resonance imaging scans were obtained using a 3.0T scanner to extract the mean amplitude of low-frequency fluctuations,mean regional homogeneity,and degree centrality.Neurological and clinical characteristics were also evaluated.We used the least absolute shrinkage and selection operator algorithm to extract features and established feedforward neural network models based solely on resting-state functional magnetic resonance imaging indicators.We then performed predictive analysis of three distinct groups based on resting-state functional magnetic resonance imaging indicators indicators combined with clinical features.Subsequently,we conducted 100 additional five-fold cross-validations to determine the most effective model for each classification task and evaluated the performance of the model using the area under the receiver operating characteristic curve.The results showed that when differentiating patients with Parkinson's disease who had freezing of gait from those who did not have freezing of gait,or from healthy controls,the models using only the mean regional homogeneity values achieved the highest area under the receiver operating characteristic curve values of 0.750(with an accuracy of 70.9%)and 0.759(with an accuracy of 65.3%),respectively.When classifying patients with Parkinson's disease who had freezing of gait from those who had no freezing of gait,the model using the mean amplitude of low-frequency fluctuation values combined with two clinical features achieved the highest area under the receiver operating characteristic curve of 0.847(with an accuracy of 74.3%).The most significant features for patients with Parkinson's disease who had freezing of gait were amplitude of low-frequency fluctuation alterations in the left parahippocampal gyrus and two clinical characteristics:Montreal Cognitive Assessment and Hamilton Depression Scale scores.Our findings suggest that radiomics features derived from resting-state functional magnetic resonance imaging indices and clinical information can serve as valuable indices for the identification of freezing of gait in Parkinson's disease. 展开更多
关键词 amplitude of low-frequency fluctuation degree centrality feedforward neural network freezing of gait machine learning parahippocampal gyrus Parkinson's disease receiver operating characteristic regional homogeneity resting-state functional magnetic resonance imaging
暂未订购
Additive Manufacturing of Functionally Graded Lattice Structures for Personalized Below-Knee Prosthetic Dampers
8
作者 Guy O'Keefe Naser A.Alsaleh +3 位作者 Mahmoud A.El-Sayed A.Jiménez Sabbah Ataya Khamis Essa 《Chinese Journal of Polymer Science》 2026年第1期173-188,I0014,共17页
Functionally graded cellular structures(FGCSs)have a multitude of applications to a wide range of industries.Utilising the ever-progressing technology of additive manufacturing(AM),FGCSs can be applied to control mate... Functionally graded cellular structures(FGCSs)have a multitude of applications to a wide range of industries.Utilising the ever-progressing technology of additive manufacturing(AM),FGCSs can be applied to control material grading and achieve the desired mechanical properties.The current study explores the design and optimisation of FGCSs for AM,with a focus on improving the compression and impact performance of below knee(BK)prosthetic limbs made of thermoplastic polyurethane(TPU).A multiscale research methodology integrating topology optimization(TO),finite element analysis(FEA),and design of experiments(Do E)was adopted to optimise lattice structures in terms of stiffness and lightweight properties.Two-unit cell designs were considered in the study:Schwarz P gyroid and body-centered cubic(BCC).Response surface methodology(RSM)was implemented to analyse the effect of minimum and maximum cell wall thickness,cell size,and unit cell type on the mechanical performance of TPU FGCS structures.The results indicated that a Schwarz P FGCS structure with cell size,minimum and maximum cell wall thickness of 6,0.9 and 2.8 mm,respectively,could be optimal for a compromise between performance and weight.In this optimized case,stiffness and volume fraction values of 684 N/mm and 0.64 were obtained,respectively.The study also presents a proof-of-concept design for a BK prosthetic damper,highlighting the potential of FGCSs to enhance patient comfort,reduce manufacturing costs,and enable personalised designs through 3D scanning and AM.The obtained results could be a step forward towards the incorporation of AM technologies in prosthetics,offering a pathway to lightweight,cost-effective,and functionally tailored solutions. 展开更多
关键词 Additive manufacturing functionally graded cellular structures Topology optimization PROSTHETICS
原文传递
Definition of critical skin defect and concepts of structural and functional repairs:Proposal and verification in a rat model
9
作者 Cong Sun Weihong Guo +4 位作者 Fang Liang Rabia Javed Weijian Hou Xingdong Zhang Qiang Ao 《Animal Models and Experimental Medicine》 2026年第1期168-182,共15页
Background:Rats are often used to prepare skin defect models.However,the skin defect sizes of the models prepared by researchers are different,and the lack of consensus on the critical-size defect makes it difficult t... Background:Rats are often used to prepare skin defect models.However,the skin defect sizes of the models prepared by researchers are different,and the lack of consensus on the critical-size defect makes it difficult to compare their research results.Methods:The time for wound closure was evaluated and recorded through gross observation.The regression equation between the healing time and the diameter of skin defect was established,which can be used to predict the healing time for a certain skin defect size in rats.Histochemical and immunohistochemical staining was used to observe the regeneration and reconstruction of skin appendages,and the functional skin repair was quantitatively scored.Results:The critical-size defect of rats was determined based on the maximum capacity of structural skin repair,and the functional skin repair was quantitatively scored based on the regeneration and reconstruction of skin appendages.The allowable range of critical-size skin defect of SD rats lies between 45 and 50 mm in diameter.The concept of structural repair and the category of functional repair of injured skin are put forward.The regression equation between the structural skin healing time and defect diameters is established.Conclusion:The allowable range of skin critical-size defect of SD rats lies between 45 and 50 mm in diameter.The regression equation between the structural skin healing time and defect diameters can be used to predict the healing time for a certain skin defect size in rats. 展开更多
关键词 critical defect functional repair quantitative evaluation skin defect structural repair
暂未订购
A note on permanent ground dislocation due to a strike-slip fault in an alluvial valley with functionally varying material properties
10
作者 Hasan Faik Kara 《Earthquake Engineering and Engineering Vibration》 2026年第1期27-39,共13页
This study focuses on permanent surface dislocations caused by a strike-slip fault in an alluvial valley.A twodimensional mathematical model is utilized,considering the valley to have a half-cylindrical shape.The vall... This study focuses on permanent surface dislocations caused by a strike-slip fault in an alluvial valley.A twodimensional mathematical model is utilized,considering the valley to have a half-cylindrical shape.The valley medium is assumed to be isotropic,linear elastic and nonhomogeneous,such that the shear modulus of the valley has spatial dependency.The valley is surrounded by an isotropic,linear elastic and homogeneous half-space.A strike-slip fault is located at the intersection between the valley and the half-space.The problem is solved analytically by using finite Fourier transform.Displacement functions are obtained in closed-form,in terms of power series and hypergeometric function series.Unknown coefficients of these series are determined from the boundary conditions,leading to an analytical exact solution.Numerical results indicate that the nonhomogeneity of the alluvial valley material has a limited impact on permanent surface dislocations unless there is a significant variation in the material properties within the functionally graded zone.In many cases,approximating the nonhomogeneous alluvial valley as a homogeneous medium is suitable. 展开更多
关键词 alluvial valley permanent ground dislocation strike-slip fault functionally graded material
在线阅读 下载PDF
Clinical Investigation into the Functional Rehabilitation of Patients with Chronic Low Back Pain Utilizing Core Stability Training Combined with Conventional Rehabilitation
11
作者 Fei LI Jinlun WU 《Medicinal Plant》 2026年第1期40-42,45,共4页
[Objectives]To investigate the clinical efficacy of core stability training combined with conventional rehabilitation in the functional recovery of patients suffering from chronic low back pain.[Methods]A randomized c... [Objectives]To investigate the clinical efficacy of core stability training combined with conventional rehabilitation in the functional recovery of patients suffering from chronic low back pain.[Methods]A randomized controlled trial design was employed in this study.Ninety patients with chronic low back pain were recruited and randomly assigned to either a control group(n=45),which received conventional rehabilitation,or an experimental group(n=45),which received conventional rehabilitation combined with core stability training.Both groups underwent treatment for 6 weeks.Assessments were conducted using the visual analogue scale(VAS),Oswestry disability index(ODI),and finger-to-floor test prior to treatment,6 weeks following treatment,and during the follow-up period,respectively.[Results]Prior to treatment,no statistically significant differences were observed between the two patient groups in terms of general information and various baseline measurements(P>0.05).Following 6 weeks of treatment and throughout the follow-up period,both groups demonstrated significant improvements in VAS scores,ODI scores,and lumbar anteflexion range of motion compared to baseline measurements(P<0.05).Notably,the magnitude of improvement in the experimental group exceeded that of the control group,with this inter-group difference reaching statistical significance(P<0.05).No serious adverse reactions were reported during the treatment process.[Conclusions]Core stability training combined with conventional rehabilitation can significantly enhance the alleviation of pain and functional impairments in patients suffering from chronic low back pain.This approach holds valuable implications for the optimization of rehabilitation treatment protocols. 展开更多
关键词 Chronic low back pain Core stability training functional impairment PAIN
暂未订购
Classification Method of Lower Limbs Motor Imagery Based on Functional Connectivity and Graph Convolutional Network
12
作者 Yang Liu Qi Lu +2 位作者 Junjie Wu Huaichang Yin Shiwei Cheng 《Computers, Materials & Continua》 2026年第3期1674-1689,共16页
The development of brain-computer interfaces(BCI)based on motor imagery(MI)has greatly improved patients’quality of life with movement disorders.The classification of upper limb MI has been widely studied and applied... The development of brain-computer interfaces(BCI)based on motor imagery(MI)has greatly improved patients’quality of life with movement disorders.The classification of upper limb MI has been widely studied and applied in many fields,including rehabilitation.However,the physiological representations of left and right lower limb movements are too close and activated deep in the cerebral cortex,making it difficult to distinguish their features.Therefore,classifying lower limbs motor imagery is more challenging.In this study,we propose a feature extraction method based on functional connectivity,which utilizes phase-locked values to construct a functional connectivity matrix as the features of the left and right legs,which can effectively avoid the problem of physiological representations of the left and right lower limbs being too close to each other during movement.In addition,considering the topology and the temporal characteristics of the electroencephalogram(EEG),we designed a temporal-spatial convolutional network(TSGCN)to capture the spatiotemporal information for classification.Experimental results show that the accuracy of the proposed method is higher than that of existing methods,achieving an average classification accuracy of 73.58%on the internal dataset.Finally,this study explains the network mechanism of left and right foot MI from the perspective of graph theoretic features and demonstrates the feasibility of decoding lower limb MI. 展开更多
关键词 Brain-computer interface lower limb motor imagery functional connectivity temporal-spatial convolutional network
在线阅读 下载PDF
Facile and scale-up synthesis of cyano-functionalized covalent organic frameworks for selective gold recovery
13
作者 Bo Li Yuanzhe Cheng +8 位作者 Xuyang Ma Dongxu Zhao Yang Zhang Yongxing Sun Jia Chen Li Wu Liang Zhao Hongdeng Qiu Yujian He 《Chinese Chemical Letters》 2026年第1期514-519,共6页
The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Coval... The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery. 展开更多
关键词 Cyano functionalization Gold recovery Covalent organic frameworks Waste electronic and electric equipment SELECTIVITY
原文传递
Size effect on the thermal fracture behavior of collinear interface cracks in functionally graded coating/substrate structures
14
作者 Huameng WANG Zhangna XUE +1 位作者 Jianlin LIU Z.T.CHEN 《Applied Mathematics and Mechanics(English Edition)》 2026年第2期325-346,共22页
When micro/nano-scale gradient coatings are subject to large thermal gradients or high heat fluxes,the spatial size effect cannot be ignored.It is important to understand how the size effect influences the thermal fra... When micro/nano-scale gradient coatings are subject to large thermal gradients or high heat fluxes,the spatial size effect cannot be ignored.It is important to understand how the size effect influences the thermal fracture behavior of functionally graded coating/substrate structures.This study aims at analyzing the transient thermal fracture behavior of collinear interface cracks in functionally graded coating/substrate structures based on the nonlocal dual-phase-lag heat conduction model.By means of integral transform techniques,the mixed boundary problem is transformed into a set of singular integral equations,which are solved by the Chebyshev polynomials.The effects of the nonlocal parameter,coating thickness,crack spacing,and non-homogeneous parameters on the temperature and stress intensity factors(SIFs)are examined.The numerical results show that these parameters play an essential role in controlling the thermal fracture behavior of the structures,especially at micro/nano-scales. 展开更多
关键词 nonlocal dual-phase-lag heat conduction collinear interface crack functionally graded coating stress intensity factor(SIF)
在线阅读 下载PDF
Bending Analysis of Functionally Graded Material and Cracked Homogeneous Thin Plates Using Meshfree Numerical Manifold Method
15
作者 Shouyang Huang Hong Zheng +2 位作者 Xuguang Yu Ziheng Li Zhiwei Pan 《Computer Modeling in Engineering & Sciences》 2026年第3期304-340,共37页
Functionally graded material(FGM)plates are widely used in various engineering structures owing to their tailor-made mechanical properties,whereas cracked homogeneous plates constitute a canonical setting in fracture ... Functionally graded material(FGM)plates are widely used in various engineering structures owing to their tailor-made mechanical properties,whereas cracked homogeneous plates constitute a canonical setting in fracture mechanics analysis.These two classes of problems respectively embody material non-uniformity and geometric discontinuity,thereby imposing more stringent requirements on numerical methods in terms of high-order field continuity and accurate defect representation.Based on the classical Kirchhoff-Love plate theory,a numerical manifold method(MLS-NMM)incorporating moving least squares(MLS)interpolation is developed for bending analysis of FGM plates and fracture simulation of homogeneous plates with defects.The method constructs an H^(2)-regular approximation with high-order continuous weighting functions and,combined with the separation of mathematical and physical covers,establishes a unified framework that accurately handles material gradients and cracks without mesh reconstruction.For the crack tip,a singular physical cover incorporating the Williams asymptotic field is introduced to achieve local enrichment,enabling the natural capture of displacement discontinuity and stress singularity.Stress intensity factors are extracted using the interaction integral method,and the dimensionless J-integral shows a maximum relative error below 1.2%compared with the reference solution.Numerical results indicate that MLS-NMM exhibits excellent convergence performance:using 676 mathematical nodes,the nondimensional central deflection of both FGM and homogeneous plates agrees with reference solutions with a maximum relative error below 0.81%,and no shear locking occurs.A systematic analysis reveals that for a simply supported on all four edges(SSSS)FGM square plate with a/h=10,the nondimensional central deflection increases by 212%as the gradient index nrises from 0 to 5.For a homogeneous plate containing a central crack with c/a=0.6,the nondimensional central deflection increases by approximately 46%compared with the intact plate.Under weak boundary constraints(e.g.,SFSF),the deformation is markedly amplified,with the deflection reaching more than three times that under strong constraints(SCSC).The proposed method provides an efficient,reconstruction-free numerical tool for high-accuracy bending and fracture analyses of FGM and cracked thin-plate structures. 展开更多
关键词 kirchhoff-love plate theory functionally graded materials moving least squares interpolation numerical manifold method bending analysis fracture mechanics stress intensity factor
在线阅读 下载PDF
New Insight to Large Deformation Analysis of Thick-Walled Axisymmetric Functionally Graded Hyperelastic Ellipsoidal Pressure Vessel Structures:A Comparison between FEM and PINNs
16
作者 Azhar G.Hamad Nasser Firouzi Yousef S.Al Rjoub 《Computers, Materials & Continua》 2026年第5期403-430,共28页
The accurate mechanical analysis of thick-walled pressure vessel structures composed of advanced materials,such as hyperelastic and functionally graded materials(FGMs),is critical for ensuring their safety and optimiz... The accurate mechanical analysis of thick-walled pressure vessel structures composed of advanced materials,such as hyperelastic and functionally graded materials(FGMs),is critical for ensuring their safety and optimizing their design.However,conventional numerical methods can face challenges with the non-linearities inherent in hyperelasticity and the complex spatial variations in FGMs.This paper presents a novel hybrid numerical approach combining Physics-Informed Neural Networks(PINNs)with Finite Element Method(FEM)derived data for the robust analysis of thick-walled,axisymmetric,heterogeneous,hyperelastic pressure vessels with elliptical geometries.A PINN framework incorporating neo-Hookean constitutive relations is developed in MATLAB.To enhance training efficiency and accuracy,the PINN’s loss function is augmented with displacement data obtained from high-fidelity FEM simulations performed in ANSYS.The methodology is rigorously validated by comparing PINN-predicted displacement and von Mises stress fields against ANSYS benchmarks for various scenarios of FGMconfigurations(with material properties varying according to a power law)subjected to internal and external pressurization.The results demonstrate excellent agreement between the proposed hybrid PINN-FEMapproach and conventional FEMsolutions across all test cases,accurately capturing complex deformation patterns and stress concentrations.This study highlights the potential of data-augmented PINNs as an effective and accurate computational tool for tackling complex solid mechanics problems involving non-linearmaterials and significant heterogeneity,offering a promising avenue for future research in engineering design and analysis. 展开更多
关键词 Finite elementmethod(FEM) physics-informed neural networks(PINNs) HYPERELASTICITY functionally graded materials(FGMs) pressure vessels hybrid numerical methods axisymmetric analysis
在线阅读 下载PDF
Synthetic metabolic engineering of functional crops:Boosting nutrition and human health 被引量:3
17
作者 Nan Chai Jie Xu +12 位作者 Ruixiang Zhang Guangzhou Li Jun Wen Liying Su Yang Xue Tie Li Jialin Liu Dongchang Zeng Jiantao Tan Jiaqi Huang Letian Chen Yao-Guang Liu Qinlong Zhu 《The Crop Journal》 2026年第1期8-21,共14页
A growing global population and the increasing prevalence of diet-related health issues such as“hidden hunger”,obesity,hypertension,and diabetes necessitate a fundamental rethinking of crop design and breeding.Synth... A growing global population and the increasing prevalence of diet-related health issues such as“hidden hunger”,obesity,hypertension,and diabetes necessitate a fundamental rethinking of crop design and breeding.Synthetic metabolic engineering offers a method to modify and redesign metabolic pathways to increase the nutritional value of crops.We summarize recent advances in the biofortification of key nutrients including provitamin A,vitamin C,vitamin B9,iron,zinc,anthocyanins,flavonoids,and unsaturated fatty acids.We discuss the potential of multi-gene stacking,gene editing,enzyme engineering,and artificial intelligence in synthetic metabolic engineering.We propose future research directions and potential solutions centered on leveraging AI-driven systems biology,precision gene editing,enzyme engineering,agrobacterium-mediated genotype-independent transformation,and modular metabolic engineering strategies to develop next-generation nutritionally enhanced super crops and transform global food systems. 展开更多
关键词 Synthetic biology Synthetic metabolism engineering functional crops Multigene stacking and gene editing Artificial intelligence
在线阅读 下载PDF
Differing functions of two CYP716 genes for saikosaponin biosynthesis in Bupleurum chinense 被引量:1
18
作者 Kaimi Dong Hua Chen +14 位作者 Ma Yu Shiying Wang Xue Yin Chuanxin Mo Meng Zhang Yuchan Li Yong Luo Zeru Yu Zisong Yang Jun Zhao Chao Xin Wenshuai Chen Zhen Ni Zheyong Xue Jianhe Wei 《The Crop Journal》 2026年第1期224-234,共11页
Saikosaponins are the major pharmacologically active components in Bupleurum genus and exhibit significant application potential in multiple fields such as immune regulation and anti-tumor activity.To elucidate the bi... Saikosaponins are the major pharmacologically active components in Bupleurum genus and exhibit significant application potential in multiple fields such as immune regulation and anti-tumor activity.To elucidate the biosynthetic pathway of saikosaponins,we identified two cytochrome P450 monooxygenases,CYP716A41 and CYP716Y4,in Bupleurum chinense.These enzymes catalyze the C-28 oxidation and C-16 hydroxylation of oleanane-type triterpene skeletons,respectively.The catalytic efficiency of CYP716A41 from a southern B.chinense variety was significantly higher than that from a northern variety.Molecular docking and mutagenesis experiments revealed that amino acid residues at sites 9 and 35 may contribute to this difference in catalytic efficiency.Additionally,under cold stress,the expression levels of both CYP450 genes and the saikosaponin contents in the leaves of southern varieties were significantly higher compared to those in northern varieties.The variation in the catalytic efficiency of CYP716A41 and the differential expression of the two CYP450 genes under cold stress during winter are associated with the differences in saikosaponin biosynthesis in the leaves of southern and northern B.chinense varieties.This is consistent with the distinct medicinal usage practices observed between southern and northern China. 展开更多
关键词 Bupleurum chinense Medicinal tissue utilization Saikosaponin biosynthesis pathway CYP716 functional verification
在线阅读 下载PDF
Microglia overexpressing brain-derived neurotrophic factor promote vascular repair and functional recovery in mice after spinal cord injury 被引量:2
19
作者 Fanzhuo Zeng Yuxin Li +6 位作者 Xiaoyu Li Xinyang Gu Yue Cao Shuai Cheng He Tian Rongcheng Mei Xifan Mei 《Neural Regeneration Research》 2026年第1期365-376,共12页
Spinal cord injury represents a severe form of central nervous system trauma for which effective treatments remain limited.Microglia is the resident immune cells of the central nervous system,play a critical role in s... Spinal cord injury represents a severe form of central nervous system trauma for which effective treatments remain limited.Microglia is the resident immune cells of the central nervous system,play a critical role in spinal cord injury.Previous studies have shown that microglia can promote neuronal survival by phagocytosing dead cells and debris and by releasing neuroprotective and anti-inflammatory factors.However,excessive activation of microglia can lead to persistent inflammation and contribute to the formation of glial scars,which hinder axonal regeneration.Despite this,the precise role and mechanisms of microglia during the acute phase of spinal cord injury remain controversial and poorly understood.To elucidate the role of microglia in spinal cord injury,we employed the colony-stimulating factor 1 receptor inhibitor PLX5622 to deplete microglia.We observed that sustained depletion of microglia resulted in an expansion of the lesion area,downregulation of brain-derived neurotrophic factor,and impaired functional recovery after spinal cord injury.Next,we generated a transgenic mouse line with conditional overexpression of brain-derived neurotrophic factor specifically in microglia.We found that brain-derived neurotrophic factor overexpression in microglia increased angiogenesis and blood flow following spinal cord injury and facilitated the recovery of hindlimb motor function.Additionally,brain-derived neurotrophic factor overexpression in microglia reduced inflammation and neuronal apoptosis during the acute phase of spinal cord injury.Furthermore,through using specific transgenic mouse lines,TMEM119,and the colony-stimulating factor 1 receptor inhibitor PLX73086,we demonstrated that the neuroprotective effects were predominantly due to brain-derived neurotrophic factor overexpression in microglia rather than macrophages.In conclusion,our findings suggest the critical role of microglia in the formation of protective glial scars.Depleting microglia is detrimental to recovery of spinal cord injury,whereas targeting brain-derived neurotrophic factor overexpression in microglia represents a promising and novel therapeutic strategy to enhance motor function recovery in patients with spinal cord injury. 展开更多
关键词 ANGIOGENESIS apoptosis brain-derived neurotrophic factor colony stimulating factor 1 receptor inflammation MICROGLIA motor function spinal cord injury vascular endothelial growth factor
暂未订购
The Asymptotic Distribution of General Divisor Problem Associated to Dedekind Zeta Function over Certain Sequences
20
作者 HUA Guodong 《数学进展》 北大核心 2026年第2期292-314,共23页
Let K_(j)/Q,1≤j≤ν,ν≥2 be quadratic fields with pairwise coprime discriminants Dj,and let τ_(kj)^(K_(j))(n)be the divisor function associated to Dedekind zeta function SK_(j)(s).In this paper,we consider a multid... Let K_(j)/Q,1≤j≤ν,ν≥2 be quadratic fields with pairwise coprime discriminants Dj,and let τ_(kj)^(K_(j))(n)be the divisor function associated to Dedekind zeta function SK_(j)(s).In this paper,we consider a multidimensional general divisor problem related to the τ_(kj)^(K_(j))(n)involving several number fields over square integers,by establishing the corresponding asymptotic formula.As an application,we also obtain the asymptotic formula of variance of these coefi icients. 展开更多
关键词 non-normal cubic field Dekekind zeta function divisor problem
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部