This paper focuses on the instability mechanism of an isolated pillar, caused by time-dependent skin degradation and strength heterogeneity. The time-dependent skin degradation is simulated with a non-linear rheologic...This paper focuses on the instability mechanism of an isolated pillar, caused by time-dependent skin degradation and strength heterogeneity. The time-dependent skin degradation is simulated with a non-linear rheological model capable of simulating tertiary creep, whereby two different pillar failure cases are investigated. The first case is of an isolated pillar in a deep hard rock underground mine and subjected to high stresses. The results show that pillar degradation is limited to the regions near the surface or the skin until two months after ore extraction. Afterwards degradation starts to extend deeper into the pillar, eventually leaving a highly-stressed pillar core due to stress transfer from the failed skin.Rockburst potential indices show that the risk increases exponentially at the core as time goes by. It is then demonstrated that the progressive skin degradation cannot be simulated with conventional strain-softening model assuming brittle failure. The parametric study with respect to the degree of heterogeneity reveals that heterogeneity is key to the occurrence of progressive skin degradation. The second case investigated in this study is pillar failure taking place in a very long period. Such failure becomes significantly important when assessing the risk for ground subsidence caused by pillar collapse in an abandoned mine. The analysis results demonstrate that the employed non-linear rheological model can simulate gradual skin degradation taking place over several hundred years. The percentage of damage zone volume within the pillar is merely 1% after a lapse of one days and increases to 50% after one hundred years, indicating a high risk for pillar collapse in the long term. The vertical displacements within the pillar also indicate the risk of subsidence. The proposed method is suitable for evaluating the risk of ground surface subsidence above an abandoned mine.展开更多
Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional...Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.展开更多
Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the ten...Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the tensile stress in the area has exceeded the tensile strength of the soil,leading to local instability.To explore the impact of tensile failure behavior on the stability and failure modes of reservoir landslides,the Huangtupo Riverside Slump#1 is taken as a case study.By considering local tensile failure,potential tensile cracks are incorporated into the analysis via the limit equilibrium method and reliability theory.The reliability of landslides under different tensile failure scenarios is quantified.Strain-softening characteristics of the soil are combined to further analyze the failure transmission path of the landslide.Finally,these potential failure modes were validated through physical model tests.The results show that cracks developing at rear positions reduce the stability of the slope and increase the probability of instability.During the destruction process,retrogressive failures with multiple sliding surfaces are likely to occur.However,tensile failure at the forefront reduces the likelihood of an individual slide mass descending.Progressive failure results in both regular and skip transmission patterns.Additionally,cracks and water level changes can also lead to shifts in the positions of the most dangerous blocks.Therefore,in practical landslide analysis and prevention,it is necessary to consider local tensile damage and identify potential tensile crack locations in advance to optimize prevention measures and accurately evaluate landslide risk.展开更多
A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relax...A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relaxation.Distributed optical fiber sensing was used to measure strains across the sample surface by helically wrapping the single-mode fiber around the cylindrical sample.Close agreement was observed between the circumferential strains obtained from the optical fibers and the extensometer.The reconstructed full-field strain contours show strain heterogeneity from the crack closure phase,and the strains in the later deformation phase are dominantly localized within the former high-strain zone.The Gini coefficient was used to quantify the degree of strain localization and shows an initial increase during the crack closure phase,a decrease during the linear elastic phase,and a subsequent increase during the post-yielding phase.This behavior corresponds to a process of initial localization from an imperfect boundary condition,homogenization,and eventual relocalization prior to the macroscopic failure of the sample.The transient strain rate decay during the stress relaxation phase was quantified using the p-value in the“Omori-like"power law function.A higher initial stress at the onset of relaxation results in a lower p-value,indicating a slower strain rate decay.As the sample approaches macroscopic failure,the lowest p-value shifts from the most damaged zone to adjacent areas,suggesting stress redistribution or crack propagation in deformed crystalline rocks under stress relaxation conditions.展开更多
Background Frailty is common and significantly impacts prognosis in heart failure(HF). The Vulnerable Elders Survey-13(VES-13), widely used in oncogeriatrics and public health, remains unexplored as a frailty screenin...Background Frailty is common and significantly impacts prognosis in heart failure(HF). The Vulnerable Elders Survey-13(VES-13), widely used in oncogeriatrics and public health, remains unexplored as a frailty screening tool in HF outpatients. In this study, we prospectively evaluated VES-13 against a multimodal screening assessment in detecting frailty and predicting individual risk of adverse prognosis.Methods Frailty was assessed at the initial visit using both a multimodal approach, incorporating Barthel Index, Older American Resources and Services scale, Pfeiffer Test, abbreviated Geriatric Depression Scale, age > 85 years, lacking support systems,and VES-13. Patients scoring ≥ 3 on VES-13 or meeting at least one multimodal criterion were classified as frail. Endpoints included all-cause mortality, a composite of death or HF hospitalization, and recurrent HF hospitalizations.Results A total of 301 patients were evaluated. VES-13 identified 40.2% as frail and the multimodal assessment 33.2%. In Cox regression analyses, frailty identified by VES-13 showed greater prognostic significance than the multimodal assessment for allcause mortality(HR = 3.70 [2.15–6.33], P < 0.001 vs. 2.40 [1.46–4.0], P = 0.001) and the composite endpoint(HR = 3.13 [2.02–4.84], P< 0.001 vs. 1.96 [1.28–2.99], P = 0.002). Recurrent HF hospitalizations were four times more frequent in VES-13 frail patients while two times in those identified as frail by the multimodal assessment. Additionally, stratifying patients by VES-13 tertiles provided robust risk differentiation.Conclusions VES-13, a simple frailty tool, outperformed a comprehensive multimodal assessment and could be easily integrated into routine HF care, highlighting its clinical utility in identifying patients at risk for poor outcomes.展开更多
In deep coal mining,surrounding rock is subjected to both high in-situ stress and intense mining disturbances,leading to significant time-dependent behavior.Accurately capturing this behavior is essential for predicti...In deep coal mining,surrounding rock is subjected to both high in-situ stress and intense mining disturbances,leading to significant time-dependent behavior.Accurately capturing this behavior is essential for predicting long-term roadway stability,necessitating the development of a reliable constitutive creep model and numerical simulation approach.In this study,creep experiments were conducted on pre-damaged rock with varying initial damage levels to investigate the time-dependent mechanical properties.Based on the experimental results,an accelerated-creep criterion was proposed,and an elastic-viscoplastic creep damage model(EVPCD)was established that simultaneously considers the effects of time-dependent damage and instantaneous damage caused by stress disturbances on rock creep behavior.Subsequently,the effectiveness of the proposed creep model was verified using experimental data,and the secondary development of the EVPCD model was completed based on the FLAC3D platform.Following this,a long-term stability analysis method of deep surrounding rock that accounts for excavation-and mining-induced disturbances was proposed.Using the main roadway of Xutuan Coal Mine as a case study,numerical simulations were carried out to investigate the time-dependent deformation and failure characteristics of the surrounding rock following excavation and mining disturbance.Combined with on-site monitoring of the surrounding rock damage areas,the results indicate that the EVPCD outperforms the CVISC and Nishihara models in predicting the time-dependent behavior of deep surrounding rock.展开更多
Formation control of multiple spacecraft has attracted extensive research attention.However,achieving reliable performance under sensor failures remains a significant challenge.This paper develops an integrated framew...Formation control of multiple spacecraft has attracted extensive research attention.However,achieving reliable performance under sensor failures remains a significant challenge.This paper develops an integrated framework that jointly designs distributed observers and local controllers to ensure robust formation control in the presence of external disturbances and sensor malfunctions.Treating the spacecraft formation as a single interconnected system,each spacecraft constructs a distributed observer that estimates the overall system state by incorporating both its own measurements and the predicted control information shared among the spacecraft.Based on the observer estimates,a local control law is synthesized to maintain the desired formation.Rigorous theoretical analysis and numerical simulations demonstrate that the proposed integrated approach effectively guarantees formation stability and resilience against sensor failures and disturbances.展开更多
Objective:This integrative review aims to synthesize observational evidence on the prevalence,predictors,and psychosocial correlates of death anxiety in patients with hear t failure(HF).Methods:A comprehensive literat...Objective:This integrative review aims to synthesize observational evidence on the prevalence,predictors,and psychosocial correlates of death anxiety in patients with hear t failure(HF).Methods:A comprehensive literature search was conducted using 5 major databases:Scopus,Pub Med,Science Direct,Embase,and Pro Quest.Inclusion criteria were primary research studies published in English between January 2014 and March 2025 that quantitatively assessed death anxiety among patients with HF and explored its associations with demographic,clinical,or psychosocial variables.Results:A total of 12 eligible studies were identified and systematically reviewed,revealing that death anxiety is moderate to high among most samples.Key predictors of this anxiety included older age,feelings of loneliness,low socioeconomic status,and longer duration of HF.Additionally,several studies highlighted protective factors such as spiritual orientation,religious coping,and resilience.Interventions,including cognitive-behavioral therapy(CBT)and illness perception training,showed significant reductions in death anxiety.Conclusions:Death anxiety is a prevalent and impactful concern among Patients with HF,influenced by both individual and contextual factors.Routine assessment and integration of psychosocial and spiritual care—alongside evidence-based psychological interventions—are essential to address this critical aspect of HF management.展开更多
AIM:To investigate the underlying causes of surgical failure and reoperation management in patients with rhegmatogenous retinal detachment(RRD)who underwent scleral buckle surgery at our institution.METHODS:This was a...AIM:To investigate the underlying causes of surgical failure and reoperation management in patients with rhegmatogenous retinal detachment(RRD)who underwent scleral buckle surgery at our institution.METHODS:This was a single-center,retrospective,descriptive study.The clinical data of 368 patients(387 eyes)with RRD who underwent scleral buckling(SB)surgery between August 2013 and July 2023 at our institution were collected.The aim was to analyze the causes of recurrence and the rationale for selecting reoperation methods.RESULTS:Totally 368 patients(387 eyes)were included in the analysis,comprising 222 males and 146 females.The average age was 30.26±14.18 years,and the mean follow-up duration was(48.33±20.39)mo.The success rate of SB surgery was 90.2%.Recurrent retinal detachment occurred in 38 eyes.Based on surgical records,the causes of SB failure were analyzed.The recurrence causes included abnormal compression ridge position(position,height,or width)in 14 eyes(36.8%,14/38),hole omission in 11 eyes(29.0%,11/38),proliferative vitreoretinopathy(PVR)in 10 eyes(26.3%,10/38),and new holes in 3 eyes(7.9%,3/38).Among these,8 eyes(21.1%,8/38)underwent repeat SB surgery,while the remaining 30 eyes(78.9%,30/38)underwent pars plana vitrectomy(PPV).Regarding tamponade agents,silicone oil was used in 11 eyes(36.7%,11/30),C_(3)F_(8) gas in 12 eyes(40.0%,12/30),and sterile air in 7 eyes(23.3%,7/30).CONCLUSION:SB surgery demonstrates a high success rate in the treatment of RRD.However,abnormal compression ridge position,missed holes during surgery,and PVR are the primary causes of SB failure.After addressing the reasons for failure,re-SB surgery or PPV can be effective alternatives.展开更多
BACKGROUND Anxiety,depression,and other negative emotions are common among patients with chronic renal failure(CRF).Analyzing the factors related to negative emotions is necessary to provide targeted nursing care.AIM ...BACKGROUND Anxiety,depression,and other negative emotions are common among patients with chronic renal failure(CRF).Analyzing the factors related to negative emotions is necessary to provide targeted nursing care.AIM To explore the correlations among life satisfaction,pleasure levels,and negative emotions in patients with CRF.METHODS One hundred patients with CRF who received therapy at the First Affiliated Hospital of Jinzhou Medical University between December 2022 and February 2025 were included.The Depression,Anxiety,and Stress Scale(DASS-21),Satisfaction with Life Scale(SWLS),and Temporal Experience of Pleasure Scale(TEPS)were used to evaluate negative emotions,life satisfaction,and pleasure level,respectively.Pearson’s correlation coefficient analyzed the correlation between life satisfaction,pleasure level,and negative emotions.Linear regression analysis identified the factors affecting negative emotions.RESULTS The average DASS-21 score among patients with CRF was 51.90±2.30,with subscale scores of 17.90±1.50 for depression,18.53±1.18 for anxiety,and 15.47±2.36 for stress,all significantly higher than the domestic norm(P<0.05).The average SWLS score was 22.17±4.90.Correlation analysis revealed a negative correlation between the SWLS and total DASS-21 scores(P<0.05),but not with the individual depression,anxiety,or stress dimensions.The average TEPS score was 67.80±8.34.TEPS scores were negatively correlated with the DASS-21 score and the stress dimension(P<0.05),but not with depression or anxiety.Linear regression analysis showed that TEPS scores significantly influenced DASS-21 scores(P<0.05).CONCLUSION Patients with CRF experience high levels of negative emotions,which are negatively correlated with life satisfaction and pleasure.Furthermore,pleasure level had an impact on negative emotions.展开更多
BACKGROUND Congenital hypothyroidism(CH)is a common condition in both preterm and term infants characterized by either thyroid gland absence or hypofunctionality.The clinical association of refractory lactic acidosis ...BACKGROUND Congenital hypothyroidism(CH)is a common condition in both preterm and term infants characterized by either thyroid gland absence or hypofunctionality.The clinical association of refractory lactic acidosis and heart failure has rarely been observed in cases of pediatric patients with CH pathology.Here,we explored the etiological relationship between CH,heart failure,and refractory lactic acidosis to reflect the importance of thyroid function screening in neonates with heart disease.CASE SUMMARY A 33-day-old extremely premature female infant presented with tachypnea,respiratory distress,recurrent infections,and abdominal distension postnatal.On admission to our facility,she had cardiomegaly,hepatomegaly,and lactic acidosis(revealed on blood gas analysis),with lactate progressively rising to 25 mmol/L.Chest radiographs showed pulmonary congestion,while echocardiography revealed cardiac enlargement,left ventricular wall thickening,and pericardial effusion.Initial management aimed at correcting acidosis and treating heart failure proved ineffective.After reassessment,thyroid function tests showed significantly decreased triiodothyronine,free triiodothyronine,thyroxine,and free thyroxine levels,with a significantly increased thyroidstimulating hormone level,confirming a CH diagnosis.Levothyroxine was administered,resulting in rapid correction of lactic acidosis and gradual improvement of thyroid function and systemic symptoms,culminating in full recovery and discharge.We also reviewed the relevant literature on thyroid and cardiac dysfunctions in order to explore their deeper association.CONCLUSION This case links CH-induced heart failure with refractory lactic acidosis,urging prompt thyroid screening in affected neonates to reduce mortality.展开更多
Objective:Heart failure(HF)is a complex clinical syndrome that affects nearly 64 million individuals globally.Frequent hospital readmissions lead to poor health outcomes,impact quality of life(QoL),and are associated ...Objective:Heart failure(HF)is a complex clinical syndrome that affects nearly 64 million individuals globally.Frequent hospital readmissions lead to poor health outcomes,impact quality of life(QoL),and are associated with high mortality rates.This study assessed readmissions,mortality,and QoL outcomes in patients with HF in a tertiary care hospital setting.Methods:Patients aged≥18 years with HF,who visited the tertiary care hospital in Karad,India were included in the study(November2019 to October 2021).Demographics,disease characteristics,and condition at discharge were recorded using the medical records of patients.The quantitative data included readmission rates and mortality rates.The qualitative aspects describing patients'QoL were assessed using a patient-reported 21-question QoL questionnaire.Results:A total of 98 patients,predominantly male(63.3%),with a mean age of 62.9 years were included.The majority of the patients(80.6%)required<15 days of hospitalization.The 2-year readmission rate was 24.4%,while the mortality rate was 43.9%.Self-care pattern showed that patients seemed to be taking mild to average care while taking good care was rare.The QoL data showed that 22.4% were living a good quality life,44.9% average,while 32.7% were living a low-quality life.Better education and better self-care were associated with a low rate of readmission.Conclusions:We were able to assess the incidence of readmission,mortality,and QoL in patients with HF in a tertiary care hospital setting.The study showed that HF impacts patients'physical,emotional,and psychological wellbeing.展开更多
Dynamic disturbances with various frequencies could trigger different failure modes of deep excavations.Superimposed on this static stress are dynamic disturbances due to various dynamic vibrations,e.g.excavation blas...Dynamic disturbances with various frequencies could trigger different failure modes of deep excavations.Superimposed on this static stress are dynamic disturbances due to various dynamic vibrations,e.g.excavation blasting,blasting,tunnel boring machine(TBM)vibration,rockburst wave,earthquakes.Specifically,these dynamic sources are characterized by a wide range of wave frequencies f,resulting in differences in failure modes.A series of true-triaxial compression tests were conducted on granite to simulate the excavation-induced stress path in three-dimensional(3D)stresses.Subsequently,a dynamic disturbance with various frequencies was applied to a cuboid specimen,to reveal the behavior associated with brittle failure.The dynamic disturbance with frequencies f of 5 Hz,10 Hz,and 40 Hz generates less disturbed energy components in the granite together with higher peak strength.However,dynamic disturbances with f of 20 Hz and 30 Hz resulted in a lower peak strength;the peak strength of the rock increases sp albeit it decreases at first,then increases.This U-shaped phenomenon relates to the natural frequency of the granite under such stress conditions.Different rock lithologies consisting of diverse mineral composition,respond differently to each sensitive resonance frequency.Interestingly,the weak disturbance stress with a high frequency f and low amplitude A increases the ratio of crack damage to peak strength(scd/sp)in the granite.This leads to the inhibition of the expansion of the granite during the dynamic disturbance process.Multiple penetrating tensileeshear cracks appear in the s3-direction as the disturbance frequency f increases.展开更多
Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens un...Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens under varying temperature and cycle conditions,employing acoustic emission monitoring,digital image correlation,and three-dimensional scanning technology.A systematic analysis was conducted on the patterns of damage evolution,failure precursor,and response mechanisms under combined thermal and cyclic loading.Experimental results show that both P-wave velocity and tensile strength degrade significantly with increasing temperature and cycle count,with temperature having a more pronounced effect than cycle count.Notably,damage evolution exhibits a dual-threshold behavior in which degradation accelerates markedly above 400℃ and stabilizes after 5 thermal cycles.Fracture surfaces evolve from initially planar to rugged morphologies,with peak-valley height differences at 600℃ being approximately three times greater than those at 200℃.Furthermore,based on acoustic emission energy entropy analysis,we introduce a novel failure precursor indicator where the sustained increase and critical surge in average entropy serve as reliable early-warning signals for impending rock failure.These findings establish a solid theoretical basis and practical methodology for damage assessment and instability early-warning systems in high-temperature rock engineering.展开更多
Chronic heart failure(CHF)impairs cognitive function.Xijiaqi Formula(XJQ),a traditional Chinese medicine(TCM)used clinically to treat CHF,demonstrates potential for improving cognition in CHF patients.However,its prec...Chronic heart failure(CHF)impairs cognitive function.Xijiaqi Formula(XJQ),a traditional Chinese medicine(TCM)used clinically to treat CHF,demonstrates potential for improving cognition in CHF patients.However,its precise mechanism in treating post-CHF cognitive dysfunction remains unclear.This study systematically investigates XJQ’s effects on post-CHF cognitive dysfunction and the underlying mechanisms.The components of XJQ were identified through liquid chromatography-mass spectrometry.CHF was induced in rats via ligation of the left anterior descending coronary artery,followed by six weeks of XJQ treatment.Cardiac function was evaluated through echocardiography and hemodynamic parameters,while cognitive function was assessed using Morris water maze(MWM)and open field tests(OFT).XJQ treatment enhanced both cardiac and cognitive functions in CHF rats.Network pharmacology identified 12 core active components of XJQ and indicated its effect on cognitive dysfunction involved regulating synapses,inflammation,and phosphodiesterase 4(PDE4)-dependent cyclic adenosine monophosphate(cAMP)signaling.XJQ inhibited microglial and astrocyte activation,decreased proinflammatory cytokines,and mitigated neuronal damage.Notably,XJQ promoted synaptic repair and dendritic growth by downregulating PDE4 and upregulating cAMP,protein kinase A(PKA),cAMP-response element binding protein(CREB),brain-derived neurotrophic factor(BDNF),PSD95,and synapsin I levels.Molecular docking and Bio-layer interferometry assays confirmed direct binding of quercetin,kaempferol,isorhamnetin,and darutoside to PDE4.In conclusion,XJQ alleviates neuroinflammation and enhances synaptic plasticity to improve cognitive dysfunction in CHF rats via the PDE4/cAMP/PKA/CREB signaling pathway.These findings provide valuable insight into the heart-brain axis.展开更多
In-situ stress is a key parameter for underground mine design and rock stability analysis.The borehole overcoring technique is widely used for in-situ stress measurement,but the rheological recovery deformation of roc...In-situ stress is a key parameter for underground mine design and rock stability analysis.The borehole overcoring technique is widely used for in-situ stress measurement,but the rheological recovery deformation of rocks after stress relief introduces errors.To improve accuracy,this study proposes an in-situ stress solution theory that incorporates time-dependent stress relief effects.Triaxial stepwise loadingunloading rheological tests on granite and siltstone established quantitative relationships between instantaneous elastic recovery and viscoelastic recovery under different stress levels,confirming their impact on measurement accuracy.By integrating a dual-class elastic deformation recovery model,an improved in-situ stress solution theory was derived.Additionally,accounting for the nonlinear characteristics of rock masses,a determination method for time-dependent nonlinear mechanical parameters was proposed.Based on the CSIRO hollow inclusion strain cell,time-dependent strain correction equations and long-term confining pressure calibration equations were formulated.Finally,the proposed theory was successfully applied at one iron mine(736 m depth)in Xinjiang,China,and one coal mine(510 m depth)in Ningxia,China.Compared to classical theory,the calculated mean stress values showed accuracy improvements of 6.0%and 9.4%,respectively,validating the applicability and reliability of the proposed theory.展开更多
Background:“Qi deficiency”(a pathological state where the body’s vital energy(Qi)is insufficient or weakened,impairing physiological functions and diminishing the body’s ability to perform daily activities,defend ...Background:“Qi deficiency”(a pathological state where the body’s vital energy(Qi)is insufficient or weakened,impairing physiological functions and diminishing the body’s ability to perform daily activities,defend against illness,and maintain homeostasis)syndrome is considered a critical syndrome in traditional Chinese medicine(TCM)and is associated with poor prognosis in heart failure(HF).This study investigates the clinical,metabolic,and transcriptomic differences between heart failure patients with and without Qi deficiency syndrome.Methods:56 heart failure patients were evaluated using a Qi deficiency syndrome scale and divided into Qi deficiency syndrome(QD)and non-Qi deficiency(non-QD)groups based on the median score.Clinical characteristics,including baseline N-terminal pro-B-type natriuretic peptide(NT-proBNP),left ventricular ejection fraction(LVEF),total diuretic use during hospitalization,and 90-day rehospitalization rates,were compared between the groups.Differentially expressed genes(DEGs)and differential metabolites were identified,followed by enrichment analyses and validation using qPCR and Western blot in AC16 cardiomyocytes.Results:QD patients exhibited significantly higher NT-proBNP levels,lower LVEF,and increased 90-day rehospitalization rates.Metabolomic profiling revealed lipid metabolism disruptions,notably in linoleic acid and phospholipid pathways.Transcriptomic analysis highlighted 17 DEGs,including CISD2,a critical mitochondrial regulator,which was downregulated in QD patients.Correlation analysis identified significant associations between DEGs(e.g.,CISD2,BPGM)and lipid metabolites such as PC(16:0/P-16:0).Functional knockdown of CISD2 in AC16 cells led to upregulation of lipid oxidation enzymes ALOX15 and CYP1A2,linking CISD2 dysfunction to lipid metabolic dysregulation.Conclusion:Qi deficiency is associated with more severe heart failure symptoms,worse prognosis,and distinct metabolic and transcriptomic profiles,particularly in lipid metabolism.CISD2 emerges as a potential therapeutic target,offering new avenues for integrating molecular insights with TCM approaches to optimize HF management.展开更多
Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoret...Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.展开更多
The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the...The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.展开更多
Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combin...Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combined experimental and numerical approach to investigate the response and failure modes of a flexible ultra-high-molecular-weight polyethylene(UHMWPE)foam protective sandwich structure(UFPSS)under low-velocity impact(LVI).A finite element(FE)model,accounting for nonlinear large deformation and strain-rate-dependent material behavior,was developed for a woven-UFPSS(featuring a plain-woven fabric structure)subjected to a 50 J impact.Experimental and numerical results showed strong agreement in peak force(error<5%),maximum displacement(error<6%),and buffer time(error<8%).The impact's kinetic energy was mainly converted into internal energy of the fabric and foam materials(~50%),viscous dissipation in the foam core(12%-15%),frictional work at the contact interfaces(5%-6%),and work by the pneumatic fixture clamping force(~38%).This study provides the first investigation of the LVI performance of sandwich structures with all soft material layers,offering significant insights for the application of compliant materials in protective fields.展开更多
基金financially supported by the Natural Science and Engineering Research Council of Canada (NSERC) in partnership with Vale Ltd–Sudbury Operations, Canada, under the Collaborative Research and Development Program
文摘This paper focuses on the instability mechanism of an isolated pillar, caused by time-dependent skin degradation and strength heterogeneity. The time-dependent skin degradation is simulated with a non-linear rheological model capable of simulating tertiary creep, whereby two different pillar failure cases are investigated. The first case is of an isolated pillar in a deep hard rock underground mine and subjected to high stresses. The results show that pillar degradation is limited to the regions near the surface or the skin until two months after ore extraction. Afterwards degradation starts to extend deeper into the pillar, eventually leaving a highly-stressed pillar core due to stress transfer from the failed skin.Rockburst potential indices show that the risk increases exponentially at the core as time goes by. It is then demonstrated that the progressive skin degradation cannot be simulated with conventional strain-softening model assuming brittle failure. The parametric study with respect to the degree of heterogeneity reveals that heterogeneity is key to the occurrence of progressive skin degradation. The second case investigated in this study is pillar failure taking place in a very long period. Such failure becomes significantly important when assessing the risk for ground subsidence caused by pillar collapse in an abandoned mine. The analysis results demonstrate that the employed non-linear rheological model can simulate gradual skin degradation taking place over several hundred years. The percentage of damage zone volume within the pillar is merely 1% after a lapse of one days and increases to 50% after one hundred years, indicating a high risk for pillar collapse in the long term. The vertical displacements within the pillar also indicate the risk of subsidence. The proposed method is suitable for evaluating the risk of ground surface subsidence above an abandoned mine.
基金funding support from the National Natural Science Foundation of China(Nos.52304101 and 52204153)the China Postdoctoral Science Foundation(No.2023MD734215)+2 种基金the Youth Talent Support Program of Xi’an Association for Science and Technology(No.959202413070)the Key Research and Development Program of Shaanxi(No.2023-LL-QY-07)the Key Research and Development Program of Zhejiang(No.2023C03182).
文摘Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.
基金supported by the Major Program of National Natural Science Foundation of China(Grant No.42090055)the National Key ScientificInstruments and Equipment Development Projects of China(Grant No.41827808)the National Nature Science Foundation of China(Grant No.42207216).
文摘Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the tensile stress in the area has exceeded the tensile strength of the soil,leading to local instability.To explore the impact of tensile failure behavior on the stability and failure modes of reservoir landslides,the Huangtupo Riverside Slump#1 is taken as a case study.By considering local tensile failure,potential tensile cracks are incorporated into the analysis via the limit equilibrium method and reliability theory.The reliability of landslides under different tensile failure scenarios is quantified.Strain-softening characteristics of the soil are combined to further analyze the failure transmission path of the landslide.Finally,these potential failure modes were validated through physical model tests.The results show that cracks developing at rear positions reduce the stability of the slope and increase the probability of instability.During the destruction process,retrogressive failures with multiple sliding surfaces are likely to occur.However,tensile failure at the forefront reduces the likelihood of an individual slide mass descending.Progressive failure results in both regular and skip transmission patterns.Additionally,cracks and water level changes can also lead to shifts in the positions of the most dangerous blocks.Therefore,in practical landslide analysis and prevention,it is necessary to consider local tensile damage and identify potential tensile crack locations in advance to optimize prevention measures and accurately evaluate landslide risk.
基金support of her postdoctoral research at the GFZ Helmholtz Centre for Geosciences.P.Pan acknowledges the financial support of the National Natural Science Foundation of China(Grant No.52339001)H.Hofmann and Y.Ji acknowledge the financial support of the Helmholtz Association's Initiative and Networking Fund for the Helmholtz Young Investigator Group ARES(contract number VH-NG-1516).
文摘A multi-stage stress relaxation test was performed on a granodiorite sample to understand the deformation process prior to the macroscopic failure of brittle rocks,as well as the transient response during stress relaxation.Distributed optical fiber sensing was used to measure strains across the sample surface by helically wrapping the single-mode fiber around the cylindrical sample.Close agreement was observed between the circumferential strains obtained from the optical fibers and the extensometer.The reconstructed full-field strain contours show strain heterogeneity from the crack closure phase,and the strains in the later deformation phase are dominantly localized within the former high-strain zone.The Gini coefficient was used to quantify the degree of strain localization and shows an initial increase during the crack closure phase,a decrease during the linear elastic phase,and a subsequent increase during the post-yielding phase.This behavior corresponds to a process of initial localization from an imperfect boundary condition,homogenization,and eventual relocalization prior to the macroscopic failure of the sample.The transient strain rate decay during the stress relaxation phase was quantified using the p-value in the“Omori-like"power law function.A higher initial stress at the onset of relaxation results in a lower p-value,indicating a slower strain rate decay.As the sample approaches macroscopic failure,the lowest p-value shifts from the most damaged zone to adjacent areas,suggesting stress redistribution or crack propagation in deformed crystalline rocks under stress relaxation conditions.
文摘Background Frailty is common and significantly impacts prognosis in heart failure(HF). The Vulnerable Elders Survey-13(VES-13), widely used in oncogeriatrics and public health, remains unexplored as a frailty screening tool in HF outpatients. In this study, we prospectively evaluated VES-13 against a multimodal screening assessment in detecting frailty and predicting individual risk of adverse prognosis.Methods Frailty was assessed at the initial visit using both a multimodal approach, incorporating Barthel Index, Older American Resources and Services scale, Pfeiffer Test, abbreviated Geriatric Depression Scale, age > 85 years, lacking support systems,and VES-13. Patients scoring ≥ 3 on VES-13 or meeting at least one multimodal criterion were classified as frail. Endpoints included all-cause mortality, a composite of death or HF hospitalization, and recurrent HF hospitalizations.Results A total of 301 patients were evaluated. VES-13 identified 40.2% as frail and the multimodal assessment 33.2%. In Cox regression analyses, frailty identified by VES-13 showed greater prognostic significance than the multimodal assessment for allcause mortality(HR = 3.70 [2.15–6.33], P < 0.001 vs. 2.40 [1.46–4.0], P = 0.001) and the composite endpoint(HR = 3.13 [2.02–4.84], P< 0.001 vs. 1.96 [1.28–2.99], P = 0.002). Recurrent HF hospitalizations were four times more frequent in VES-13 frail patients while two times in those identified as frail by the multimodal assessment. Additionally, stratifying patients by VES-13 tertiles provided robust risk differentiation.Conclusions VES-13, a simple frailty tool, outperformed a comprehensive multimodal assessment and could be easily integrated into routine HF care, highlighting its clinical utility in identifying patients at risk for poor outcomes.
基金funded by the National Natural Science Foundation of China(Nos.52004098,U24B2041,and 52274079)the Key Research and Development Program of Henan Province(No.251111320400)+1 种基金the Key Research Project Plan for Higher Education Institutions in Henan Province(Nos.24A570006 and 25A570002)the Scientific and Technological Research Project in Henan Province(No.242102320061).
文摘In deep coal mining,surrounding rock is subjected to both high in-situ stress and intense mining disturbances,leading to significant time-dependent behavior.Accurately capturing this behavior is essential for predicting long-term roadway stability,necessitating the development of a reliable constitutive creep model and numerical simulation approach.In this study,creep experiments were conducted on pre-damaged rock with varying initial damage levels to investigate the time-dependent mechanical properties.Based on the experimental results,an accelerated-creep criterion was proposed,and an elastic-viscoplastic creep damage model(EVPCD)was established that simultaneously considers the effects of time-dependent damage and instantaneous damage caused by stress disturbances on rock creep behavior.Subsequently,the effectiveness of the proposed creep model was verified using experimental data,and the secondary development of the EVPCD model was completed based on the FLAC3D platform.Following this,a long-term stability analysis method of deep surrounding rock that accounts for excavation-and mining-induced disturbances was proposed.Using the main roadway of Xutuan Coal Mine as a case study,numerical simulations were carried out to investigate the time-dependent deformation and failure characteristics of the surrounding rock following excavation and mining disturbance.Combined with on-site monitoring of the surrounding rock damage areas,the results indicate that the EVPCD outperforms the CVISC and Nishihara models in predicting the time-dependent behavior of deep surrounding rock.
基金supported by the National Natural Science Foundation of China(62088101,62522307,62273045,U2341213)Beijing Nova Program(20230484481)。
文摘Formation control of multiple spacecraft has attracted extensive research attention.However,achieving reliable performance under sensor failures remains a significant challenge.This paper develops an integrated framework that jointly designs distributed observers and local controllers to ensure robust formation control in the presence of external disturbances and sensor malfunctions.Treating the spacecraft formation as a single interconnected system,each spacecraft constructs a distributed observer that estimates the overall system state by incorporating both its own measurements and the predicted control information shared among the spacecraft.Based on the observer estimates,a local control law is synthesized to maintain the desired formation.Rigorous theoretical analysis and numerical simulations demonstrate that the proposed integrated approach effectively guarantees formation stability and resilience against sensor failures and disturbances.
文摘Objective:This integrative review aims to synthesize observational evidence on the prevalence,predictors,and psychosocial correlates of death anxiety in patients with hear t failure(HF).Methods:A comprehensive literature search was conducted using 5 major databases:Scopus,Pub Med,Science Direct,Embase,and Pro Quest.Inclusion criteria were primary research studies published in English between January 2014 and March 2025 that quantitatively assessed death anxiety among patients with HF and explored its associations with demographic,clinical,or psychosocial variables.Results:A total of 12 eligible studies were identified and systematically reviewed,revealing that death anxiety is moderate to high among most samples.Key predictors of this anxiety included older age,feelings of loneliness,low socioeconomic status,and longer duration of HF.Additionally,several studies highlighted protective factors such as spiritual orientation,religious coping,and resilience.Interventions,including cognitive-behavioral therapy(CBT)and illness perception training,showed significant reductions in death anxiety.Conclusions:Death anxiety is a prevalent and impactful concern among Patients with HF,influenced by both individual and contextual factors.Routine assessment and integration of psychosocial and spiritual care—alongside evidence-based psychological interventions—are essential to address this critical aspect of HF management.
文摘AIM:To investigate the underlying causes of surgical failure and reoperation management in patients with rhegmatogenous retinal detachment(RRD)who underwent scleral buckle surgery at our institution.METHODS:This was a single-center,retrospective,descriptive study.The clinical data of 368 patients(387 eyes)with RRD who underwent scleral buckling(SB)surgery between August 2013 and July 2023 at our institution were collected.The aim was to analyze the causes of recurrence and the rationale for selecting reoperation methods.RESULTS:Totally 368 patients(387 eyes)were included in the analysis,comprising 222 males and 146 females.The average age was 30.26±14.18 years,and the mean follow-up duration was(48.33±20.39)mo.The success rate of SB surgery was 90.2%.Recurrent retinal detachment occurred in 38 eyes.Based on surgical records,the causes of SB failure were analyzed.The recurrence causes included abnormal compression ridge position(position,height,or width)in 14 eyes(36.8%,14/38),hole omission in 11 eyes(29.0%,11/38),proliferative vitreoretinopathy(PVR)in 10 eyes(26.3%,10/38),and new holes in 3 eyes(7.9%,3/38).Among these,8 eyes(21.1%,8/38)underwent repeat SB surgery,while the remaining 30 eyes(78.9%,30/38)underwent pars plana vitrectomy(PPV).Regarding tamponade agents,silicone oil was used in 11 eyes(36.7%,11/30),C_(3)F_(8) gas in 12 eyes(40.0%,12/30),and sterile air in 7 eyes(23.3%,7/30).CONCLUSION:SB surgery demonstrates a high success rate in the treatment of RRD.However,abnormal compression ridge position,missed holes during surgery,and PVR are the primary causes of SB failure.After addressing the reasons for failure,re-SB surgery or PPV can be effective alternatives.
文摘BACKGROUND Anxiety,depression,and other negative emotions are common among patients with chronic renal failure(CRF).Analyzing the factors related to negative emotions is necessary to provide targeted nursing care.AIM To explore the correlations among life satisfaction,pleasure levels,and negative emotions in patients with CRF.METHODS One hundred patients with CRF who received therapy at the First Affiliated Hospital of Jinzhou Medical University between December 2022 and February 2025 were included.The Depression,Anxiety,and Stress Scale(DASS-21),Satisfaction with Life Scale(SWLS),and Temporal Experience of Pleasure Scale(TEPS)were used to evaluate negative emotions,life satisfaction,and pleasure level,respectively.Pearson’s correlation coefficient analyzed the correlation between life satisfaction,pleasure level,and negative emotions.Linear regression analysis identified the factors affecting negative emotions.RESULTS The average DASS-21 score among patients with CRF was 51.90±2.30,with subscale scores of 17.90±1.50 for depression,18.53±1.18 for anxiety,and 15.47±2.36 for stress,all significantly higher than the domestic norm(P<0.05).The average SWLS score was 22.17±4.90.Correlation analysis revealed a negative correlation between the SWLS and total DASS-21 scores(P<0.05),but not with the individual depression,anxiety,or stress dimensions.The average TEPS score was 67.80±8.34.TEPS scores were negatively correlated with the DASS-21 score and the stress dimension(P<0.05),but not with depression or anxiety.Linear regression analysis showed that TEPS scores significantly influenced DASS-21 scores(P<0.05).CONCLUSION Patients with CRF experience high levels of negative emotions,which are negatively correlated with life satisfaction and pleasure.Furthermore,pleasure level had an impact on negative emotions.
文摘BACKGROUND Congenital hypothyroidism(CH)is a common condition in both preterm and term infants characterized by either thyroid gland absence or hypofunctionality.The clinical association of refractory lactic acidosis and heart failure has rarely been observed in cases of pediatric patients with CH pathology.Here,we explored the etiological relationship between CH,heart failure,and refractory lactic acidosis to reflect the importance of thyroid function screening in neonates with heart disease.CASE SUMMARY A 33-day-old extremely premature female infant presented with tachypnea,respiratory distress,recurrent infections,and abdominal distension postnatal.On admission to our facility,she had cardiomegaly,hepatomegaly,and lactic acidosis(revealed on blood gas analysis),with lactate progressively rising to 25 mmol/L.Chest radiographs showed pulmonary congestion,while echocardiography revealed cardiac enlargement,left ventricular wall thickening,and pericardial effusion.Initial management aimed at correcting acidosis and treating heart failure proved ineffective.After reassessment,thyroid function tests showed significantly decreased triiodothyronine,free triiodothyronine,thyroxine,and free thyroxine levels,with a significantly increased thyroidstimulating hormone level,confirming a CH diagnosis.Levothyroxine was administered,resulting in rapid correction of lactic acidosis and gradual improvement of thyroid function and systemic symptoms,culminating in full recovery and discharge.We also reviewed the relevant literature on thyroid and cardiac dysfunctions in order to explore their deeper association.CONCLUSION This case links CH-induced heart failure with refractory lactic acidosis,urging prompt thyroid screening in affected neonates to reduce mortality.
文摘Objective:Heart failure(HF)is a complex clinical syndrome that affects nearly 64 million individuals globally.Frequent hospital readmissions lead to poor health outcomes,impact quality of life(QoL),and are associated with high mortality rates.This study assessed readmissions,mortality,and QoL outcomes in patients with HF in a tertiary care hospital setting.Methods:Patients aged≥18 years with HF,who visited the tertiary care hospital in Karad,India were included in the study(November2019 to October 2021).Demographics,disease characteristics,and condition at discharge were recorded using the medical records of patients.The quantitative data included readmission rates and mortality rates.The qualitative aspects describing patients'QoL were assessed using a patient-reported 21-question QoL questionnaire.Results:A total of 98 patients,predominantly male(63.3%),with a mean age of 62.9 years were included.The majority of the patients(80.6%)required<15 days of hospitalization.The 2-year readmission rate was 24.4%,while the mortality rate was 43.9%.Self-care pattern showed that patients seemed to be taking mild to average care while taking good care was rare.The QoL data showed that 22.4% were living a good quality life,44.9% average,while 32.7% were living a low-quality life.Better education and better self-care were associated with a low rate of readmission.Conclusions:We were able to assess the incidence of readmission,mortality,and QoL in patients with HF in a tertiary care hospital setting.The study showed that HF impacts patients'physical,emotional,and psychological wellbeing.
基金supported by the National Natural Science Foundation of China(Grant Nos.52222810 and 52178383).
文摘Dynamic disturbances with various frequencies could trigger different failure modes of deep excavations.Superimposed on this static stress are dynamic disturbances due to various dynamic vibrations,e.g.excavation blasting,blasting,tunnel boring machine(TBM)vibration,rockburst wave,earthquakes.Specifically,these dynamic sources are characterized by a wide range of wave frequencies f,resulting in differences in failure modes.A series of true-triaxial compression tests were conducted on granite to simulate the excavation-induced stress path in three-dimensional(3D)stresses.Subsequently,a dynamic disturbance with various frequencies was applied to a cuboid specimen,to reveal the behavior associated with brittle failure.The dynamic disturbance with frequencies f of 5 Hz,10 Hz,and 40 Hz generates less disturbed energy components in the granite together with higher peak strength.However,dynamic disturbances with f of 20 Hz and 30 Hz resulted in a lower peak strength;the peak strength of the rock increases sp albeit it decreases at first,then increases.This U-shaped phenomenon relates to the natural frequency of the granite under such stress conditions.Different rock lithologies consisting of diverse mineral composition,respond differently to each sensitive resonance frequency.Interestingly,the weak disturbance stress with a high frequency f and low amplitude A increases the ratio of crack damage to peak strength(scd/sp)in the granite.This leads to the inhibition of the expansion of the granite during the dynamic disturbance process.Multiple penetrating tensileeshear cracks appear in the s3-direction as the disturbance frequency f increases.
基金supported by National Natural Science Foundation of China (Nos.52264006,52364004,and 52464005)the Guizhou Provincial Science and Technology Foundation (No.GCC[2022]005-1)。
文摘Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses.This study performed Brazilian splitting tests on granite specimens under varying temperature and cycle conditions,employing acoustic emission monitoring,digital image correlation,and three-dimensional scanning technology.A systematic analysis was conducted on the patterns of damage evolution,failure precursor,and response mechanisms under combined thermal and cyclic loading.Experimental results show that both P-wave velocity and tensile strength degrade significantly with increasing temperature and cycle count,with temperature having a more pronounced effect than cycle count.Notably,damage evolution exhibits a dual-threshold behavior in which degradation accelerates markedly above 400℃ and stabilizes after 5 thermal cycles.Fracture surfaces evolve from initially planar to rugged morphologies,with peak-valley height differences at 600℃ being approximately three times greater than those at 200℃.Furthermore,based on acoustic emission energy entropy analysis,we introduce a novel failure precursor indicator where the sustained increase and critical surge in average entropy serve as reliable early-warning signals for impending rock failure.These findings establish a solid theoretical basis and practical methodology for damage assessment and instability early-warning systems in high-temperature rock engineering.
基金supported by the National Natural Science Foundation of China(Nos.82430116 and 82574622)the Special Fund of Central Committee High Level Chinese Medicine Hospital(Nos.DZMG-LJRC-0014,DZMG-ZJXY-23013)+1 种基金Chinese Medicine Inheritance and Innovation“Thousand Million”Talents Project(Qihuang Project 2021)Qihuang Scholarsthe Medical and Health Industry Development Project of Tongzhou District(2023).
文摘Chronic heart failure(CHF)impairs cognitive function.Xijiaqi Formula(XJQ),a traditional Chinese medicine(TCM)used clinically to treat CHF,demonstrates potential for improving cognition in CHF patients.However,its precise mechanism in treating post-CHF cognitive dysfunction remains unclear.This study systematically investigates XJQ’s effects on post-CHF cognitive dysfunction and the underlying mechanisms.The components of XJQ were identified through liquid chromatography-mass spectrometry.CHF was induced in rats via ligation of the left anterior descending coronary artery,followed by six weeks of XJQ treatment.Cardiac function was evaluated through echocardiography and hemodynamic parameters,while cognitive function was assessed using Morris water maze(MWM)and open field tests(OFT).XJQ treatment enhanced both cardiac and cognitive functions in CHF rats.Network pharmacology identified 12 core active components of XJQ and indicated its effect on cognitive dysfunction involved regulating synapses,inflammation,and phosphodiesterase 4(PDE4)-dependent cyclic adenosine monophosphate(cAMP)signaling.XJQ inhibited microglial and astrocyte activation,decreased proinflammatory cytokines,and mitigated neuronal damage.Notably,XJQ promoted synaptic repair and dendritic growth by downregulating PDE4 and upregulating cAMP,protein kinase A(PKA),cAMP-response element binding protein(CREB),brain-derived neurotrophic factor(BDNF),PSD95,and synapsin I levels.Molecular docking and Bio-layer interferometry assays confirmed direct binding of quercetin,kaempferol,isorhamnetin,and darutoside to PDE4.In conclusion,XJQ alleviates neuroinflammation and enhances synaptic plasticity to improve cognitive dysfunction in CHF rats via the PDE4/cAMP/PKA/CREB signaling pathway.These findings provide valuable insight into the heart-brain axis.
基金supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2024ZD1700201)the National Natural Science Foundation of China(Nos.U2034206,51974014 and 51574014)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515011631)the National Key Research and Development Project of China(No.2022YFC3004601)。
文摘In-situ stress is a key parameter for underground mine design and rock stability analysis.The borehole overcoring technique is widely used for in-situ stress measurement,but the rheological recovery deformation of rocks after stress relief introduces errors.To improve accuracy,this study proposes an in-situ stress solution theory that incorporates time-dependent stress relief effects.Triaxial stepwise loadingunloading rheological tests on granite and siltstone established quantitative relationships between instantaneous elastic recovery and viscoelastic recovery under different stress levels,confirming their impact on measurement accuracy.By integrating a dual-class elastic deformation recovery model,an improved in-situ stress solution theory was derived.Additionally,accounting for the nonlinear characteristics of rock masses,a determination method for time-dependent nonlinear mechanical parameters was proposed.Based on the CSIRO hollow inclusion strain cell,time-dependent strain correction equations and long-term confining pressure calibration equations were formulated.Finally,the proposed theory was successfully applied at one iron mine(736 m depth)in Xinjiang,China,and one coal mine(510 m depth)in Ningxia,China.Compared to classical theory,the calculated mean stress values showed accuracy improvements of 6.0%and 9.4%,respectively,validating the applicability and reliability of the proposed theory.
基金supported by the Sanming Project of Medicine in Shenzhen[SZZYSM202206001]National Natural Science Foundation of China[82004320 and 82374383]+3 种基金Natural Science Foundation of Guangdong Province of China[2022A1515011710 and 2022A1515010679]Shenzhen Science and Technology Innovation Committee[JCYJ20220530141407017 and JCYJ20240813153619026]2024 High-quality Development Research Project of Shenzhen Bao’an Public Hospital[YNXM2024078]and Shenzhen Bao’an Chinese Medicine Hospital Research Program[BAZYY20220702].
文摘Background:“Qi deficiency”(a pathological state where the body’s vital energy(Qi)is insufficient or weakened,impairing physiological functions and diminishing the body’s ability to perform daily activities,defend against illness,and maintain homeostasis)syndrome is considered a critical syndrome in traditional Chinese medicine(TCM)and is associated with poor prognosis in heart failure(HF).This study investigates the clinical,metabolic,and transcriptomic differences between heart failure patients with and without Qi deficiency syndrome.Methods:56 heart failure patients were evaluated using a Qi deficiency syndrome scale and divided into Qi deficiency syndrome(QD)and non-Qi deficiency(non-QD)groups based on the median score.Clinical characteristics,including baseline N-terminal pro-B-type natriuretic peptide(NT-proBNP),left ventricular ejection fraction(LVEF),total diuretic use during hospitalization,and 90-day rehospitalization rates,were compared between the groups.Differentially expressed genes(DEGs)and differential metabolites were identified,followed by enrichment analyses and validation using qPCR and Western blot in AC16 cardiomyocytes.Results:QD patients exhibited significantly higher NT-proBNP levels,lower LVEF,and increased 90-day rehospitalization rates.Metabolomic profiling revealed lipid metabolism disruptions,notably in linoleic acid and phospholipid pathways.Transcriptomic analysis highlighted 17 DEGs,including CISD2,a critical mitochondrial regulator,which was downregulated in QD patients.Correlation analysis identified significant associations between DEGs(e.g.,CISD2,BPGM)and lipid metabolites such as PC(16:0/P-16:0).Functional knockdown of CISD2 in AC16 cells led to upregulation of lipid oxidation enzymes ALOX15 and CYP1A2,linking CISD2 dysfunction to lipid metabolic dysregulation.Conclusion:Qi deficiency is associated with more severe heart failure symptoms,worse prognosis,and distinct metabolic and transcriptomic profiles,particularly in lipid metabolism.CISD2 emerges as a potential therapeutic target,offering new avenues for integrating molecular insights with TCM approaches to optimize HF management.
基金support of the National Natural Science Foundation of China(Grant Nos.52179116 and 51991392)the support of Key Deployment Projects of Chinese Academy of Sciences(Grant No.ZDRW-ZS-2021-3).
文摘Shield tunneling in saturated ground poses challenges due to the potential risk of ground collapse resulting from seepage force and inadequate support pressure.This study employed a laboratory model test and a theoretical validation to elucidate the mechanisms of face failure and subsequent ground collapse in saturated ground during slurry pressure-balanced shield(SPBS)tunneling operations.A slurry circulation system was developed to ensure steady shield tunneling and to replicate the phenomena of ground collapse.Investigations into shield tunneling parameters and ground responses,including soil pressure,pore water pressure,and surface subsidence,were conducted to understand the mechanisms of face failure and subsequent ground collapse.The theoretical solution for the critical collapse pressure of the tunnel face,based on the rotational failure mechanism,was validated through the comparison with the experimentally determined critical collapse pressure.The results indicate that:(1)appropriate adjustments of tunneling parameters are crucial for promoting filtercake formation,maintaining chamber pressure,and minimizing ground subsidence;(2)chamber pressure,soil pressure,pore water pressure,and ground subsidence are closely correlated with shield tunneling parameters and the formation of filter cake;(3)ground collapse follows a continuous failure mode due to the destruction of filtercake and the decrease in chamber pressure;(4)the soil pressure at the cutterhead is more sensitive to disturbances from shield tunneling than chamber pressure;and(5)experimentally determined critical collapse pressures is consistent with the theoretical solution of limit analysis.
基金Project supported by the National Key Research and Development Program of China(Grant No.2023YFA1609000)the National Natural Science Foundation of China(Grant Nos.U2341222,U2441248,12275061,and 12075069)。
文摘The failure mechanisms and structural damage of SiC MOSFETs induced by heavy ion irradiation were demonstrated.The findings reveal three degradation modes,depending on the drain voltage.At a relatively low voltage,the damage is triggered by the formation and activation of gate latent damage(LDs),with damage concentrated in the gate oxide.The second degradation mode involves permanent leakage current degradation,with damage progressively transitioning from the oxide to the SiC material as the drain voltage escalates.Ultimately,the device undergoes catastrophic burnout above certain voltages,characterized by the lattice temperature reaching the sublimation point of SiC,resulting in surface cavity and complete structural destruction.This paper presents a comprehensive investigation of SiC MOSFETs under heavy ion exposure,providing radiation resistance methods of SiC-based devices for aerospace applications.
基金supported by the Zhenjiang Key R&D Plan(GY2021009)Lianyungang City Major Technology Breakthrough(CGJBGS2104)+2 种基金National Natural Science Foundation of China under Grant(12302456)National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact under Grant(6142902241601)China Postdoctoral Science Foundation under Grants(2025M774217)。
文摘Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combined experimental and numerical approach to investigate the response and failure modes of a flexible ultra-high-molecular-weight polyethylene(UHMWPE)foam protective sandwich structure(UFPSS)under low-velocity impact(LVI).A finite element(FE)model,accounting for nonlinear large deformation and strain-rate-dependent material behavior,was developed for a woven-UFPSS(featuring a plain-woven fabric structure)subjected to a 50 J impact.Experimental and numerical results showed strong agreement in peak force(error<5%),maximum displacement(error<6%),and buffer time(error<8%).The impact's kinetic energy was mainly converted into internal energy of the fabric and foam materials(~50%),viscous dissipation in the foam core(12%-15%),frictional work at the contact interfaces(5%-6%),and work by the pneumatic fixture clamping force(~38%).This study provides the first investigation of the LVI performance of sandwich structures with all soft material layers,offering significant insights for the application of compliant materials in protective fields.
