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On a broadband vibration isolator with tunable stiffness:from quasi-zero-stiffness to zero-stiffness behavior 认领 引用 被引量：2
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作者 N.A.SAEED Lei HOU +3 位作者 Haiming YI A.A.SHUKUR S.M.ALAMRY S.M.EL-SHOURBAGY 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2026年第2期255-282,共28页
A novel vibration isolation system designed for superior performance in low-frequency environments is proposed in this work.The isolator is based on a unique hexagonal arrangement of linear springs,allowing for an adj... A novel vibration isolation system designed for superior performance in low-frequency environments is proposed in this work.The isolator is based on a unique hexagonal arrangement of linear springs,allowing for an adjustable geometric configuration via the initial inclination angle.Based on the principle of Lagrangian mechanics,the equation of motion governing the structural dynamics is rigorously derived.The system is modeled as a strongly nonlinear single-degree-of-freedom dynamical system,loaded with a normalized payload and subject to harmonic base excitation.To analyze the steady-state response,the harmonic balance method is employed,providing accurate predictions of the payload's vibration amplitude and displacement transmissibility as functions of both the base excitation amplitude and frequency.The analysis reveals a direct relationship between the isolator's geometric and stiffness parameters and its load-bearing capacity,leading to the identification of three distinct operational regimes.Depending on the unloaded initial inclination angle,the equivalent stiffness ratio,and the payload design configuration,the system can exhibit one of three vibration isolation modes:(i)the quasizero stiffness(QZS)isolation mode,(ii)the zero linear stiffness with controllable nonlinear stiffness,and(iii)the full-band perfect zero stiffness.The vibration isolation performance of the proposed structure is thoroughly discussed for all three oscillation modes in terms of frequency response curves,displacement transmissibility,and time-domain responses.The key novel finding is that this structure can operate as a full-band,high-performance vibration isolator when the initial inclination angle is designed to be a right angle,enabling full isolation of the maximum possible payload.Moreover,the analytical results and numerical simulations demonstrate that the isolator's displacement transmissibility T with the unit dB tends to-∞as the air-damping coefficient approaches zero,enabling ideal vibration isolation across the entire excitation frequency range.These analytical insights are validated through comprehensive numerical simulations,which show excellent agreement with the theoretical predictions. 展开更多
关键词 nonlinear vibration isolation quasi-zero stiffness(QZS)structure full-band vibration isolator harmonic balance method displacement transmissibility
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Water Swelling-induced Stiffness Enhancement of Polymer Hydrogels 认领 引用 被引量：1
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作者 Yi Yu Wei Zhou +1 位作者 Tao Chen Wei Lu 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2026年第6期1749-1759,I0012,共11页
Polymer hydrogels with variable stiffness demonstrate immense practical application value,particularly when utilizing water as a trigger medium,which significantly expands their prospects in soft robotics,bioelectroni... Polymer hydrogels with variable stiffness demonstrate immense practical application value,particularly when utilizing water as a trigger medium,which significantly expands their prospects in soft robotics,bioelectronics,and artificial muscles.However,existing water-induced stiffening hydrogel rely on ionic liquids and inorganic salts,posing leakage risks during prolonged use.Here,we proposed a strategy for mechanically strengthening hydrogel through water-induced phase separation.By designing a polymer matrix featuring hydrophilic oligomeric ethylene glycol methacrylate(OEGMA)and hydrophobic methyl methacrylate(MMA)moieties,this poly[methyl methacrylate-co-poly(ethylene glycol)methacrylate][P(MMAx-co-OEGMAy)]hydrogel exhibited reversible stiffness switching across four orders of magnitude(from 1.88×10-2MPa to201.63 MPa)upon water stimulation.This abrupt stiffness enhancement stemmed from strong hydrogen bonding between water molecules and hydrophilic OEGMA segments,facilitating spontaneous aggregation and phase separation of hydrophobic MMA segments.The resulting hydrophobic MMA domains formed dynamic physical crosslinking points,thereby enhancing the hydrogel's stiffness.Furthermore,the hydrogel exhibited a time-dependent,multi-stage stiffness enhancement during water swelling.As proof of concept,it was employed as a shape-memory component to explore its application in the controllable programming of multi-stage complex shapes,offering novel design insights for developing environmentally friendly,high-mechanical-performance smart hydrogel materials. 展开更多
关键词 Polymer hydrogel Water-induced phase separation Stiffness enhancement Hydrogen bonding Shape memory
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An improved nonlinear vibration absorber with adjustable stiffness and rotating mass 认领 引用 被引量：1
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作者 Ke-Fan Xu Zhuo-Da Zhou +1 位作者 Ye-Wei Zhang Li-Qun Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第3期146-157,共12页
A novel approach for vibration reduction is proposed by improving an adjustable stiffness nonlinear vibration absorber(NVA)with a rotating mass system.The adjustable stiffness is realized by a buckling Euler beam and ... A novel approach for vibration reduction is proposed by improving an adjustable stiffness nonlinear vibration absorber(NVA)with a rotating mass system.The adjustable stiffness is realized by a buckling Euler beam and an active control system.The rotating mass is consisted of a primary mass block and two rotating mass blocks.The dynamic responses are analyzed based on nonlinear output frequency response functions.The results indicate that,in comparison to the adjustable stiffness NVA,the enhanced NVA can efficiently suppress the resonance in steady state response.Moreover,the new vibration absorber can improve the robustness of the adjustable stiffness NVA.The mass ratio and the angular velocity are two key parameters of the new vibration absorber with optimal values for effective vibration reduction.The new vibration absorber introduces new possibilities for incorporating the adjustable stiffness and the rotating mass system in the design of NVA. 展开更多
关键词 Nonlinear vibration absorber Adjustable stiffness Rotating mass Vibration reduction
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Analytical solution for longitudinal seismic response of variable stiffness tunnel with isolation layers under shear waves 认领 引用
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作者 LIU Xiang YANG Jiao-jiao +3 位作者 LI Kui-chen LU Tong JIANG An-nan FANG Qian 《Journal of Central South University》 SCIE EI CAS CSCD 2026年第6期2844-2867,共24页
Seismic isolation design typically emphasizes transverse responses of tunnels,with comparatively limited research on longitudinal isolation responses.Previous analytical solutions for isolation response are inapplicab... Seismic isolation design typically emphasizes transverse responses of tunnels,with comparatively limited research on longitudinal isolation responses.Previous analytical solutions for isolation response are inapplicable to variable stiffness tunnels.To address research gaps,analytical solutions for longitudinal seismic responses of variable stiffness tunnels with isolation layers are proposed.The solution can be applied to engineering practice.The mechanical model of isolation layers is developed using the Kelvin model.The variable stiffness tunnel is simplified as two semi-infinite beams embedded in homogeneous and isotropic soil layers.Governing equations are solved using integral transformations and continuity conditions.Analytical expressions are obtained by introducing displacement phase angles to simulate traveling wave effects.The proposed analytical solutions are validated through comparisons with results from existing literature and verified using numerical simulations.Parametric sensitivity analyses are conducted to investigate effects of tunnels with and without an isolation layer,isolation layer thickness and elastic modulus,tunnel stiffness ratio,and wavelength and amplitude of shear waves on seismic responses of variable stiffness tunnels.Changes in stiffness have a more significant effect on internal forces than displacements.Additionally,isolation layer's thickness and elastic modulus can be optimized through our method to balance structural performance and economic efficiency. 展开更多
关键词 isolation layer variable stiffness tunnel analytical solution seismic response shear waves
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Stiffness evaluation and experimental test of a novel redundantly actuated parallel machining robot 认领 引用
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作者 Hanliang Fang Jian Wang +2 位作者 Shuyi Ge Fufu Yang Jun Zhang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2026年第1期413-422,共10页
Parallel machining robot is a new type of robotized equipment for high-efficiency machining structural com-ponents with complex geometries.Terminal rigidity is of great importance index for such type of equipment,whic... Parallel machining robot is a new type of robotized equipment for high-efficiency machining structural com-ponents with complex geometries.Terminal rigidity is of great importance index for such type of equipment,which affects their load capacity and working accuracy.Before a parallel machining robot can be used for heavy-load and high-efficiency machining,its terminal rigidity should be evaluated systematically.The present study is to quantitatively reveal the stiffness properties of a previously invented Z4 redundantly actuated parallel ma-chining robot(RAPMR).For this purpose,two critical issues,i.e.,stiffness modelling and index construction,are clarified to carry out stiffness evaluation of the Z4 RAPMR.Firstly,drawing on the screw theory,a semi-analytic stiffness model of the proposed RAPMR is established at a component level.Secondly,a set of virtual work-based stiffness indices is constructed to evaluate the terminal rigidity of parallel robots.Those indices have a consistent physical unit in describing linear and angular terminal rigidity.With these indices,the local and the global stiffness performance of the Z4 RAPMR are predicted.Thirdly,a laboratory prototype of the proposed RAPMR is fabricated.And the experimental test is performed to verify the correctness of the established stiffness model.The present work is expected to provide fundamental information for further light-weight design and rigidity enhancement. 展开更多
关键词 Parallel machining robot Redundantly actuated Terminal rigidity Stiffness model Experimental test
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Design of a nonlinear stiffness metastructure isolator for powered wearable devices vibration isolation 认领 引用
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作者 Shikai Jin Wenjie Ge +2 位作者 Bin Liu Zhuo Wang Ning Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第3期86-103,共18页
The vibration control performance of powered wearable devices(PWDs)directly affects the health and comfort of the wearer.Effective vibration isolation technology has become a fundamental aspect of next-generation wear... The vibration control performance of powered wearable devices(PWDs)directly affects the health and comfort of the wearer.Effective vibration isolation technology has become a fundamental aspect of next-generation wearable device design.This study proposes a highly integrated nonlinear stiffness metastructure vibration isolator design for PWDs to address vibration isolation requirements in such scenarios.In this paper,we systematically analyze and experimentally verify the static characteristics of the proposed metastructure vibration isolator through numerical analysis,analytical model and experimental methods,and deeply discuss its dynamic transmissibility characteristics.Among them,we analytically derive and calculate the cantilever beam oscillator of the metastructure vibration isolator and verify the numerical results.Utilizing the mode superposition method,we examine the variations in vibration transmissibility under different operating conditions and geometric parameters.Experimental results are consistent with the numerical calculation results and demonstrate that the isolator exhibits excellent vibration attenuation within the vibration isolation frequency range of 53-61 Hz,achieving a minimum vibration transmissibility of−38 dB.The metastructure vibration isolation system presented in this study successfully achieves the anticipated vibration suppression performance,offering a novel approach to vibration isolation design for PWDs. 展开更多
关键词 Powered wearable devices Nonlinear stiffness Vibration isolator Metastructure
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Impact of biochar particle size and content on small strain stiffness characteristics of amended expansive clay 认领 引用
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作者 GAO Zhiao KONG Lingwei +4 位作者 WANG Yong QIN Hui SHANG Zhaowei LIN Huanwen ZHOU Yuan 《Journal of Mountain Science》 SCIE CSCD 2026年第7期3459-3476,共18页
Biochar-modified clay has garnered growing interest in geotechnical engineering,yet existing research has predominantly focused on swelling-shrinkage behavior,strength,and hydraulic conductivity,with comparatively lit... Biochar-modified clay has garnered growing interest in geotechnical engineering,yet existing research has predominantly focused on swelling-shrinkage behavior,strength,and hydraulic conductivity,with comparatively little attention given to stiffness evolution.This study systematically investigates the effects of biochar particle size(<0.075mm,0.075-0.425 mm,and 0.425-2 mm)and mass content(0%,5%,10%,and 15%)on the small-strain stiffness characteristics of amended expansive clay under varying effective consolidation stresses.Microstructural changes were examined using scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP).Results indicate that finer biochar particles markedly enhance initial stiffness but also accelerate its degradation with strain,whereas coarser particles attenuate stiffness reduction more slowly.Increasing biochar content generally promotes more brittle behavior.A modified Hardin-Drnevich model accurately captures the maximum shear modulus and its decay behavior across all biochar contents,with prediction errors within 15%.A logarithmic relationship between dimensionless confining pressure and reference shear strain reveals that higher confining pressures mitigate the influence of biochar content on normalized stiffness attenuation.Microstructural analyses show that fine biochar particles fill interaggregate pores,leading to a pronounced stiffening effect,while medium and coarse particles bond with soil particles through surface adsorption,enhancing stiffness via interparticle adhesion.These findings offer practical guidance for sustainable soil improvement strategies in mountain and slope environments,where stiffness-dependent deformation is critical. 展开更多
关键词 Biochar particle size Biochar content Expansive clay Small strain stiffness Microstructure
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An investigation on self-powered semi-active vibration isolation system with adjustable stiffness 认领 引用
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作者 Kefan XU Zhuoda ZHOU +2 位作者 Yaohua LIU Yewei ZHANG Liqun CHEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2026年第5期1019-1040,共22页
The semi-active vibration isolator(SAVI) has the characteristics of dynamic adjustable stiffness and damping, which can achieve high-efficient broadband vibration isolation. However, the issue of the energy supply con... The semi-active vibration isolator(SAVI) has the characteristics of dynamic adjustable stiffness and damping, which can achieve high-efficient broadband vibration isolation. However, the issue of the energy supply constraints on its application in engineering. A novel self-powered semi-active vibration isolator(SPSAVI) with adjustable stiffness is proposed to achieve vibration reduction and energy harvesting. The piezoelectric materials are adhered onto the buckling beam structure to gather the electrical energy generated by vibration, which can supply the energy demand of the piezoelectric actuator for achieving the self-supply capability. An electromechanical coupling dynamic model of the SPSAVI is established under Newton's second law. The vibration reduction and self-powered effect of the SPSAVI are analyzed by the harmonic balance method.The results indicate that the SPSAVI can effectively improve the vibration isolation performance and achieve the self-powered effect. When the external excitation is 0.65g in which g is the gravity acceleration, the SPSAVI can achieve a stable self-powered effect. 展开更多
关键词 semi-active vibration isolator(SAVI) adjustable stiffness piezoelectric material vibration reduction energy harvesting
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Active vibration isolation based on absolute-relative dynamic stiffness control via multi-sensor information fusion 认领 引用
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作者 Zhiwei Huang Jiulin Wu +4 位作者 Fuxiang Zhang Rui Zhou Hu Li Xuedong Chen Wei Jiang 《ENGINEERING Mechanical Engineering》 SCIE CAS CSCD 2026年第2期129-152,共24页
The requirements for isolating outer vibration and suppressing inner disturbances are increasingly stringent and even approaching extreme limits in integrated circuit manufacturing,precision measurement,scientific exp... The requirements for isolating outer vibration and suppressing inner disturbances are increasingly stringent and even approaching extreme limits in integrated circuit manufacturing,precision measurement,scientific experiments,etc.In comparison with passive isolation,active control methods can significantly enhance vibration isolation performance.However,different control strategies are mainly effective in different frequency domains,and performance may deteriorate in some frequency domains due to sensor noises.Active vibration isolation based on absolute-relative dynamic stiffness control via multi-sensor information fusion is proposed in this paper.This method can substantially improve vibration attenuation capability and position stability performances in broad bandwidth,with a particular focus on improving the resonance peak suppression capability in the ultra-low frequency domain.First,the effects of different control strategies on vibration isolation in different frequency domains are analyzed,and the hybrid control strategy is proposed by using both absolute relative signal feedback.Considering the noise characteristics of absolute velocity sensors and relative displacement sensors,different filters are accordingly adopted to improve vibration isolation performance.A one-dimensional experimental platform is established to conduct vibration control experiments under different configurations.The results demonstrate that vibration isolation performance across a wide frequency range can be significantly improved,and the proposed method further proves effective for micro-vibration systems.Typically,transmissibility can be reduced to as low as -30 dB at 1 Hz and -48 dB at 2 Hz,with guarantee of less than -50 dB within 10-50 Hz.Additionally,compliance results show 10-40 dB performance improvements across the broad frequency range(0.1-100 Hz)compared with the passive system. 展开更多
关键词 active vibration control dynamic stiffness multi-sensor information fusion absolute velocity feedback relative displacement feedback
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Effect of percussive massage treatment and static stretching on muscle tone,stiffness,and strength recovery after exercise-induced muscle fatigue:A randomized controlled study 认领 引用
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作者 Gangrui Chen Zhongke Gu +2 位作者 Dongling Xin Yuxuan Qi Jiansong Dai 《Sports Medicine and Health Science》 CAS CSCD 2026年第5期524-530,共7页
The aim of this study was to compare the effects of percussive massage treatment and static stretching on muscle tone,stiffness,and strength recovery following exercise fatigue.Sixty subjects were randomly divided int... The aim of this study was to compare the effects of percussive massage treatment and static stretching on muscle tone,stiffness,and strength recovery following exercise fatigue.Sixty subjects were randomly divided into three groups:a control group(CG,n=20),a static stretching group(SSG,n=20),and a percussive massage treatment group(PMTG,n=20).Following exercise-induced muscle fatigue,interventions were applied,including supine rest,static stretching,and percussive massage treatment.Muscle tone,stiffness,and muscle strength indicators were assessed at five time points:before the exercise(Pre-exercise),immediately after exercise(Post-exercise),immediately after therapy intervention(Post-0),24 hours(h)after therapy intervention(Post-24 h),and 48 h after therapy intervention(Post-48 h).Results:At Post-0,muscle tone and stiffness in both the control group and static stretching group were significantly higher than Pre-exercise,while in the percussive massage treatment group,there were no statistically significant differences compared to Pre-exercise.At Post-48 h,peak torque in the control group was significantly lower than Pre-exercise.In contrast,the percussive massage treatment group and static stretching group showed no significant differences at Post-48 h compared to Pre-exercise.These findings indicated that percussive massage therapy is immediately effective in mitigating muscle tone and stiffness after exercise fatigue,whereas static stretching and percussive massage therapy facilitate the recovery of muscle strength within 48 h. 展开更多
关键词 Percussive massage therapy Static stretching Muscle tone and stiffness Muscle strength
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Liver stiffness at baseline as a marker of hepatocellular carcinoma in cirrhosis:A matched analysis 认领 引用
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作者 Varun Mehta Manjeet Kumar Goyal +5 位作者 Yogesh Kumar Gupta Abhinav Gupta Manisha Khubber Tanisha Sehgal Prabhav Mehta Omesh Goyal 《World Journal of Gastrointestinal Pathophysiology》 2026年第2期28-38,共11页
BACKGROUND Early hepatocellular carcinoma(HCC)detection in cirrhosis remains suboptimal despite semi-annual ultrasound and alpha-fetoprotein surveillance.Advanced fibrosis is a central driver of hepatocarcinogenesis,a... BACKGROUND Early hepatocellular carcinoma(HCC)detection in cirrhosis remains suboptimal despite semi-annual ultrasound and alpha-fetoprotein surveillance.Advanced fibrosis is a central driver of hepatocarcinogenesis,and liver stiffness measurement(LSM)is a non-invasive measure of liver stiffness that may be associated with HCC risk.AIM To evaluate whether LSM by transient elastography(TE)is associated with the presence of HCC among patients with established cirrhosis.METHODS A retrospective,matched case-control study at a tertiary liver center including adults with cirrhosis and a valid TE(≥10 valid acquisitions,interquartile range60%)was conducted.Cirrhotic patients with diagnosed HCC per standard guidelines were frequency matched for age,sex,etiology,and Child-Pugh class with controls(cirrhotic patients without HCC).Multivariable logistic regression tested the association between LSM and HCC.Discrimination and cut-off points were assessed using receiver operating characteristic(ROC)analysis and Youden’s index.RESULTS A total of 262 patients(133 with HCC;129 controls)were enrolled.Median LSM was higher in the HCC cohort than in controls(31.7 kPa vs 22.6 kPa;P<0.001).Multivariate regression analysis revealed that only LSM was significantly associated with HCC(adjusted odds ratio 1.09;95%CI:1.05-1.13;P=0.0001).A cut-off of≥47 kPa had excellent discriminatory power(area under the ROC curve:0.88;95%CI:0.84-0.93).CONCLUSION A liver stiffness threshold of approximately 47 kPa may serve as a marker associated with risk of HCC,justifying intensified screening in high-risk cirrhosis;prospective validation,integration with multivariable risk models,and cost-effectiveness analyses remain essential. 展开更多
关键词 Hepatocellular carcinoma Liver cirrhosis Liver fibrosis Liver stiffness Elastography Liver stiffness measurement Hepatocellular carcinoma Cirrhosis Risk stratification Portal hypertension
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Small-strain stiffness of alkali-contaminated undisturbed lateritic soil:Resonant column test and microanalysis 认领 引用
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作者 Xiu Yue Wei Bai Lingwei Kong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第4期3096-3109,共14页
In recent years,the impact of alkali contamination on lateritic clay has gained increasing attention,but studies on small-strain stiffness remain limited.This study investigates how different concentrations of alkali ... In recent years,the impact of alkali contamination on lateritic clay has gained increasing attention,but studies on small-strain stiffness remain limited.This study investigates how different concentrations of alkali contamination affect the small-strain stiffness of undisturbed lateritic soil using resonant column tests(RCTs).Thermal analysis,scanning electron microscopy(SEM),nitrogen adsorption,and mercury intrusion porosimetry(MIP)were employed to analyze the chemical reactions and structural evolution at the microscopic level,providing a rational basis for explaining stiffness evolution.Results indicate that alkali contamination dissolves kaolinite,forming aluminosilicate gel.Dissolution increases with concentration,and gel yield peaks at pH value of 11.4 while inhibited at pH value of 12.4.The structural reorganization caused by dissolution and gel filling significantly reduces the macropore volume(>100 nm),leading to an overall densification of the structure,with the sample with pH value of 11.4 being the most compact.Alkali contamination enhances the stiffness,with maximum dynamic shear modulus(G₀)increasing and then decreasing as pH rises,while its attenuation rate first slows down and then accelerates.Both trends exhibit turning points at pH value of 11.4,where the enhancement effect is optimal.This is mainly attributed to the peak gel production at this pH,which compensates for the loss of aggregate stiffness and,together with structural reorganization,enhances inter-aggregate contact stiffness,resulting in the highest G₀and the lowest attenuation rate.This study identifies a critical pH threshold for enhancing the self-cementation and structural densification of lateritic soil,thereby providing new insights into underground contamination monitoring and sustainable foundation reinforcement. 展开更多
关键词 Alkali contamination Undisturbed lateritic soil Resonant column test(RCT) Small-strain stiffness characteristics Maximum dynamic shear modulus
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Liver stiffness-based composite indices for compensated and decompensated cirrhosis in chronic hepatitis B 认领 引用
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作者 Zhi-Zun Guo Yan Wang +2 位作者 Xiao-Xuan Liu Shan-Shan Yang Fan Yu 《World Journal of Hepatology》 2026年第6期156-165,共10页
BACKGROUND Chronic hepatitis B virus(HBV)infection remains a major global public health challenge.Accurate assessment of disease progression is essential for managing patients with chronic HBV infection.Despite the us... BACKGROUND Chronic hepatitis B virus(HBV)infection remains a major global public health challenge.Accurate assessment of disease progression is essential for managing patients with chronic HBV infection.Despite the use of liver biopsy,imaging tests,and non-invasive models,their inherent limitations restrict widespread application.Thus,there is a pressing need to establish an effective non-invasive diagnostic model for assessing disease progression in patients with chronic HBV infection,particularly one that integrates imaging tests with demographic and hematologic parameters.AIM To develop novel non-invasive composite indices for evaluating the condition of chronic HBV-infected patients.METHODS This retrospective study enrolled 132 chronic HBV-infected patients who were admitted to the Department of Infectious Diseases,Shanxi Bethune Hospital,Taiyuan,China,between August 1,2020 and June 30,2024.Demographic variables,hematological parameters,and liver stiffness measurement(LSM)were recorded.Multivariable logistic regression was constructed to identify independent predictors of chronic hepatitis B(CHB),compensated and decompensated hepatitis B cirrhosis.The logistic regression diagnostic model was fitted with the selected predictors.Receiver operating characteristic(ROC)curves were generated to assess diagnostic performance of the model.RESULTS We developed three non-invasive models-A-index for CHB,MAPTAL for compensated hepatitis B cirrhosis,and APTAL for decompensated hepatitis B cirrhosis-which achieved area under the ROC curve of 0.948,0.918,and 0.968,respectively.CONCLUSION The MAPTAL and APTAL indices,integrating LSM with routine demographic and hematologic variables,reliably predict progression to compensated and decompensated HBV-related cirrhosis,respectively. 展开更多
关键词 Liver cirrhosis Hepatitis B virus Diagnosis Non-invasive Transient elastography Liver stiffness
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Spleen stiffness accurately tracks early and sustained portal pressure changes after transjugular intrahepatic portosystemic shunt 认领 引用
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作者 Rui-Quan Zhou Pei-Jun Yang +3 位作者 Li-Guo Liu Jian-Bin Zhang Zhi-Dong Ye Hai-Dong Tan 《World Journal of Gastrointestinal Surgery》 SCIE 2026年第5期253-263,共11页
BACKGROUND Clinically significant portal hypertension(CSPH)drives major complications in cirrhosis.While hepatic venous pressure gradient is the gold standard for CSPH diagnosis,its invasiveness limits routine use.Liv... BACKGROUND Clinically significant portal hypertension(CSPH)drives major complications in cirrhosis.While hepatic venous pressure gradient is the gold standard for CSPH diagnosis,its invasiveness limits routine use.Liver stiffness measurement(LSM)and spleen stiffness measurement(SSM)offer non-invasive alternatives,but their utility in tracking transjugular intrahepatic portosystemic shunt(TIPS)-induced hemodynamic changes remains unclear.AIM To assess the correlation of LSM/SSM with baseline portocaval pressure gradient(PPG)andΔPPG,and to evalutate their predictive value for hemodynamic success(post-PPG≤10 mmHg).METHODS We retrospectively analyzed 39 patients underwent TIPS.LSM and SSM were measured via vibration-controlled transient elastography pre-and post-TIPS.PPG was recorded invasively during the procedure.Correlations between stiffness parameters and PPG were assessed using Spearman’s test;diagnostic performance was evaluated by receiver operating characteristic analysis.RESULTS PPG dropped from 17.6±4.1 mmHg to 7.0±2.3 mmHg(P<0.001).SSM decreased significantly(61.7±17.1 kPa to 26.9±11.6 kPa;P<0.001)and correlated with baseline PPG(r=0.41,P<0.001)and ΔPPG(r=-0.57,P<0.001).LSM showed no significant correlation with PPG orΔPPG.None of the stiffness metrics reliably predicted successful TIPS response(all area under the curve<0.7).CONCLUSION SSM dynamically reflects TIPS-induced portal pressure changes,outperforming LSM as a non-invasive marker.Despite limited predictive value here(small cohort,etiological heterogeneity),it remains valuable for TIPS monitoring when invasive measures are impractical. 展开更多
关键词 Portal hypertension Transjugular intrahepatic portosystemic shunt Spleen stiffness measurement Liver stiffness measurement Clinically significant portal hypertension Vibration-controlled transient elastography
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Structural Design and Performance Analysis of a Deep-Learning-Based Adaptive Variable-Stiffness Lower-Limb Rehabilitation Exoskeleton 认领 引用 被引量：1
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作者 Yingnan Wang Chenxi Wang +2 位作者 Zhixia Wang Boxun Tao Wei Wang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第4期466-480,共15页
With the continuous advancement of global rehabilitation technologies,home-based lower-limb rehabilitation exoskeletons have demonstrated broad application prospects due to their low cost and high convenience.However,... With the continuous advancement of global rehabilitation technologies,home-based lower-limb rehabilitation exoskeletons have demonstrated broad application prospects due to their low cost and high convenience.However,significant inter-patient variability,the complex and dynamic nature of the rehabilitation process,and the time-varying characteristics of knee joint torque present major challenges for these exoskeletons in accurately matching torque demands during training.Designing scientifically-grounded,personalized rehabilitation programs and precisely regulating training intensity in home settings remains a highly complex and challenging task.To address this challenge,we propose a home-use knee health monitoring system(KHMS)grounded in embodied intelligence,featuring three key innovations:(i)a four-bar variable-stiffness mechanism that provides adjustable stiffness over 10–40 N·mad;(ii)a self-powered electromagnetic module that delivers a stable 3.4 V output to reliably energize low-power wireless sensors;and(iii)an LSTM-based adaptive monitoring model that estimates knee joint torque with 95.36%accuracy and supports continuous rehabilitation-state tracking.By enabling real-time assessment and data-driven personalization based on individual recovery trajectories,the proposed KHMS facilitates scientifically grounded home training with precise intensity regulation.Overall,this work advances practical,portable rehabilitation devices that can meet community-level rehabilitation needs and promote the development of low-power artificial intelligence. 展开更多
关键词 Variable stiffness Self-powered system Deep learning Health monitoring Personalized rehabilitation Embodied intelligence
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Cumulative Triglyceride and Remnant Cholesterol Increase Arterial Stiffness:A Prospective Cohort Study 认领 引用
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作者 Bingqing Kou Yifan Zang +11 位作者 Bisen Liu Yijin Pei Chong Shen Jianxin Li Fangchao Liu Jie Cao Shufeng Chen Jianfeng Huang Dongfeng Gu Tong Wang Keyong Huang Xiangfeng Lu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2026年第6期641-651,共11页
Objective Dyslipidemia has been linked to increased arterial stiffness.However,few studies have comprehensively assessed the cumulative effects of lipid profiles on arterial stiffness.Methods Based on the initial recr... Objective Dyslipidemia has been linked to increased arterial stiffness.However,few studies have comprehensively assessed the cumulative effects of lipid profiles on arterial stiffness.Methods Based on the initial recruitment of 7,134 participants from the China-PAR cohort,we finally included 6,717 participants with up to four repeated lipid measurements between baseline(1998-2008)and the most recent follow-up(2018-2020).Cumulative exposure to total cholesterol(TC),triglycerides(TG),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),non-HDLC,and remnant cholesterol(RC)was estimated using the area under the curve method.Arterial stiffness was measured in 2018-2020 using the arterial pressure-volume index(API)and the arterial velocitypulse index(AVI),which reflect the stiffness of peripheral and central arteries,respectively.Results Participants(mean age:51.4±10.3 years)included 2,598 men(38.68%),with a mean cumulative lipid exposure duration of 14.02 years.Cumulative TG,HDL-C,and RC were significantly associated with API levels,with adjusted βs(95%confidence intervals[CIs])of 2.31(1.53,3.08),-1.14(-2.24,-0.04),and 2.39(1.52,3.25),respectively,for the highest quartile compared with the lowest quartile.Restricted cubic splines showed nonlinear associations of cumulative TG and RC with API and a linear association for HDL-C(all P<0.05).For AVI,only cumulative HDL-C showed a significant inverse association,with an adjusted β(95%CI)of-1.16(-2.12,-0.21)for the highest quartile,and a nonlinear association was observed(P<0.05).Conclusion Long-term cumulative TG and RC were associated with increased peripheral arterial stiffness but not central arterial stiffness,and cumulative HDL-C was negatively associated with both peripheral and central arterial stiffness.These findings underscore the importance of long-term TG and RC control along with maintaining adequate HDL-C levels. 展开更多
关键词 Arterial stiffness Arterial pressure-volume index Arterial velocity-pulse index Cumulative exposure Lipids
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Design and Validation of a Bionic Variable Stiffness Semi-Active Ankle-Foot Prosthesis 认领 引用
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作者 Yongxin Ma Wei Chen +7 位作者 Lei Ren Hounan Song Kunyang Wang Zhihui Qian Xu Wang Yao Zhang Guowu Wei Luquan Ren 《Journal of Bionic Engineering》 SCIE EI CSCD 2026年第3期1514-1533,共20页
Energy Storage and Return(ESR)prosthetic feet are commonly used by individuals with tibial amputations,but their fixed stiffness cannot accommodate varying walking tasks and user preferences.In contrast,semi-active pr... Energy Storage and Return(ESR)prosthetic feet are commonly used by individuals with tibial amputations,but their fixed stiffness cannot accommodate varying walking tasks and user preferences.In contrast,semi-active prostheses can adjust stiffness through control mechanisms,though their design still leaves room for improvement in biomimetic characteristics,mass,and dynamic response.In this paper,we present a bionic,variable-stiffness,semi-active ankle-foot prosthesis.Stiffness is adjusted before each ground contact by controlling the motor to alter the length of the moment arm from the ankle joint center to the point of force application,with a range of 1.78-7.01 N·m/°.Additionally,the device features a biomimetic footplate design based on the transverse arch of the human foot,which reduces weight(total weight:933 g)while guaranteeing support capacity.The prosthesis can precisely identify the phase for stiffness adjustment and achieve the widest range of adjustment during this phase.A unilateral tibial amputee participated in a preliminary clinical test involving variable-speed walking,stairs,and ramps.Preliminary single-subject data suggest that,compared to the subject's previous fixed-stiffness prosthesis,the newly designed prosthesis increases the range of motion,peak power,and energy storage during level walking,while reducing the adduction moment on the sound limb's knee joint.These findings offer initial support for the prosthesis'potential to improve the biomechanics of walking and other activities,providing insights for the development of biomimetic design. 展开更多
关键词 Amputation Semi-active prosthesis design Variable stiffness Bionic foot
Effects of joint geometric configurations on cyclic shear behavior of intermittent joints under constant normal stiffness conditions 认领 引用
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作者 Bin Wang Yujing Jiang +1 位作者 Qiangyong Zhang Hongbin Chen 《Deep Underground Science and Engineering》 EI CAS CSCD 2026年第1期233-249,共17页
Intermittent joints are common in rock masses and are subjected to cyclic shear loads from seismic events,environmental factors,and human activities.In this study,we conducted cyclic shear tests to investigate the eff... Intermittent joints are common in rock masses and are subjected to cyclic shear loads from seismic events,environmental factors,and human activities.In this study,we conducted cyclic shear tests to investigate the effect of joint geometry(persistence,overlap,and spacing)on the cyclic shear behavior of intermittent joints under constant normal stiffness conditions.Our results revealed step‐path failure surfaces comprising tensile and shear failure surfaces.Shear failure surface controlled the degradation of shear properties,with shear strength decreasing progressively with cycles,ranging from 74.07%to 97.94%.Intermittent joints exhibited significant compressibility,with dilation predominant in early cycles and compression in later ones.Shear strength and dilation were more sensitive to joint persistence and spacing than overlap.Friction coefficients showed nonmonotonic variations with cycle number.High persistence,moderate overlap,and small spacing were identified as the most destabilizing combination.These findings offer valuable insights for stability assessment and deformation characterization in deep rock engineering. 展开更多
关键词 constant normal stiffness cyclic shear load intermittent joints joint configuration shear behavior shear strength
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Enhancing Bridge Vibration Control through Optimized Quasi-Zero-Stiffness Supports under Moving Mass 认领 引用
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作者 Hamed Saber Antonio Zippo +1 位作者 Farhad S.Samani Francesco Pellicano 《Computer Modeling in Engineering & Sciences》 SCIE EI 2026年第5期586-615,共30页
Lightweight bridges are increasingly used in modern infrastructure due to their structural efficiency;however,their relatively low stiffness and damping lead to a high sensitivity to vibration excitation induced by mo... Lightweight bridges are increasingly used in modern infrastructure due to their structural efficiency;however,their relatively low stiffness and damping lead to a high sensitivity to vibration excitation induced by moving loads such as pedestrians and vehicles.Conventional vibration mitigation strategies are often insufficient to suppress low-frequency responses,which has caused the development of advanced nonlinear isolation mechanisms.This paper investigates the effectiveness of nonlinear quasi-zero stiffness supports(QZSS)in suppressing vertical vibrations of lightweight bridges.Such structures are highly susceptible to vibrations induced by moving loads because of low stiffness and dissipation,with consequent high amplification near the resonances.The bridge excitation is a moving mass,and its structure is modelled as an Euler-Bernoulli beam.The partial differential equation(PDE)is analyzed through the Bubnov-Galerkin approach after expanding the displacement field using a multimode eigenfunction series,the resulting ordinary differential equations are numerically solved using the Gauss-Kronrod algorithm.The optimal parameters of the QZSS are identified based on the criterion of maximum footbridge deflection.Comparative analyses demonstrate the superior performance of optimized nonlinear QZSS over conventional linear elastic supports.The results indicate that an optimally designed QZsS incorporated with a dashpot can reduce the maximum vibration amplitude by up to 67%under moving loads,demonstrating its effectiveness as a vibration mitigation strategy for lightweight bridges.Moreover,reductions of up to 9o%can be achieved across the remaining frequency range. 展开更多
关键词 Quasi-zero stiffness support viscous damper large span bridge vibrations numerical optimization moving load vibration reduction
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Research progress on regulation of tumor microbiota by Chinese herbal medicines targeting matrix stiffness 认领 引用
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作者 Zhao Liu Wen-Jing Zhang +6 位作者 Jia-Hua He Ting-Ting Wan Yang-Yang Bian Zhuo Li Jing Wang Yu-Ting Zhang Xiao-Ye Liu 《Traditional Medicine Research》 2026年第11期51-65,共15页
Tumor occurrence and development are co-regulated by extracellular matrix(ECM)stiffness and the intratumoral microbiota.This paper first systematically summarizes how matrix stiffness affects the composition and funct... Tumor occurrence and development are co-regulated by extracellular matrix(ECM)stiffness and the intratumoral microbiota.This paper first systematically summarizes how matrix stiffness affects the composition and function of the intratumoral microbiota.It then analyzes the regulatory roles of microbiota alterations in tumor occurrence and progression.Furthermore,it summarizes the mechanisms by which bacteria drive tumor progression,including inflammatory activation,metabolic reprogramming,and regulation of oncogenic signaling pathways.On this basis,the anti-tumor mechanisms of Chinese herbal medicines targeting the multi-dimensional regulatory network of the“matrix stiffness-bacteria-tumor”axis are discussed.This review provides an important theoretical basis for understanding bacterium-tumor interactions and for developing Chinese herbal medicine-based therapeutic strategies targeting this axis. 展开更多
关键词 extracellular matrix stiffness tumor bacteria Chinese herbal medicine
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