The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great sign...The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution.Taking the Taowanbeigou River Basin in the mine concentration area as the research object,the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method,potential ecological risk assessment method and geoaccumulation index method.On this basis,the cumulative exceeding years of specific heavy metals were predicted by using the early warning model.The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate,and the single element Cd is the main ecological risk factor,with a contribution rate of 53.6%.The overall cumulative degrees of Cu and Pb in the soil are“none-moderate”,Zn and Cd are moderate,Mo has reached an extremely strong cumulative level,Hg,As and Cr risks are not obvious,and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg.According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard,the locations over standard rates of Cu,Zn and Cd will exceed 78%in 90years,and the over standard rate of Pb will reach approximately 57%in 200 years.The cumulative exceeding standard periods of As,Cr and Hg are generally long,which basically indicates that these elements do not pose a significant potential threat to the ecological environment.Mining activities will accelerate the accumulation of heavy metals in soil.With the continuous development of mining activities,the potential pollution risk of heavy metals in the soil of mining areas will also increase.展开更多
Oiltea camellia （Camellia oleifera Abel.）, an aluminium （Al） hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application ...Oiltea camellia （Camellia oleifera Abel.）, an aluminium （Al） hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application and the characteristics of Al uptake and accumulation were investigated using laboratory and field experiments. The growth of oiltea camellia seedlings in the nutrient solution tended to be stimulated by addition of Al. Results of the field experiment showed that oiltea camellia accumulated 11 000 mg kg-1 Al in leaves within 10 months, and the average rate of Al accumulation in new leaves was about 1100 mg kg-1 month-1; however, the monthly rate varied and was highest in spring and autumn. The results of the laboratory experiment on Al uptake by oiltea camellia seedlings in CaC12 solutions with various forms of Al showed that large amounts of Al supplied as Al3＋ and Al complexes Al-malate （1：1） and Al-F （1：1） were infiuxed into oiltea camellia roots, whereas Al supplied as Al-citrate （1：1）, Al-F （1：6）, Al-oxalate （1：3）, and Al-oxalate （1：1） complexes exhibited low affinity to oiltea camellia roots. The kinetics of Al3＋ cumulative uptake in excised roots and intact plants showed a biphasic pattern, with an initial rapid phase followed by a slow phase. The Al cumulative uptake was unaffected by low temperature, which indicated that Al uptake in oiltea camellia was a passive process. The efficient influx of Al into the roots and the high transport rate in specific seasons were presumed to account for the plentiful Al accumulation in leaves of oiltea camellia.展开更多
Using cumulative quantum mechanics(CQM)and the method of generalized mathematical transfer(MGMT),we analytically study quantum nanometer cumulative-dissipative structures(CDS)and the forces arising within them,which f...Using cumulative quantum mechanics(CQM)and the method of generalized mathematical transfer(MGMT),we analytically study quantum nanometer cumulative-dissipative structures(CDS)and the forces arising within them,which focus nanostructures into regular,fractalized systems—cumulative-dissipative standing hydrogen-like excitons(atoms,molecules,lines,surfaces)and flickering crystals we discovered for the first time.(1)We demonstrate the formation of Vysikaylo standing excitons on permittivity[ε(r)]inhomogeneities in diamond in the nanoscale regions of foreign atoms.(2)For the first time,we solve the problem of measuringε(r)profiles in inhomogeneous nanoscale structures using Raman spectra(RS)[with an accuracy of up to 99.9%forε(r)and a step of up to 0.3 nm depending on the distance from the impurity atom(boron)].(3)Using our theory of Vysikaylo standing excitons,we explain the experimental observation of the degeneracy of electron spectra in standing excitons with respect to the principal quantum number n and n−1/2.By comparing the theory and experimental observations of RS in diamonds doped with boron,we solve the problem(that we formulated previously)between the de Broglie hypothesis and the classical new quantum mechanics of Dirac(which limits the-functions,or prohibits symmetric de Broglie half-waves in spherically and cylindrically symmetric quantum resonators)in favor of the de Broglie hypothesis.Based on the works of Wannier and Mott,we refine the definition of the permittivity of nanocrystals as a coefficient in electric potentials[U(r)→ε(r)U(r)]rather than electric fields[D(r)=ε(r)E(r)].We construct the most complete theory of the chemical doping of crystals(using the example of group IV crystals doped with group III and V atoms).For the first time,we raise the question of the quantum cleaning of crystals or the accumulation of dopant atoms.展开更多
Consideration is given to results of experimental and theoretical investigations how alpha-epsilon phase transition in the unalloyed iron and the 30 KhGSA steel and its absence in the austenitic 12Kh18N10T stainless s...Consideration is given to results of experimental and theoretical investigations how alpha-epsilon phase transition in the unalloyed iron and the 30 KhGSA steel and its absence in the austenitic 12Kh18N10T stainless steel influence processes under explosive deformation of spheres made of these materials.Polymorphous transition is shown to significantly effect on:amount of explosion-products energy transferred to a sphere,evolution of the converging-wave structure and its parameters,profiles of stress wave and temperature T(R,t)for some Lagrangian particles along the sphere radius,character of energy cumulation under spherical convergence of waves.展开更多
Objective Elevated depressive symptoms are well-documented among geriatric adults with cardiovascular disease(CVD);however,few studies have accounted for long-term cumulative depressive symptom exposure.This study det...Objective Elevated depressive symptoms are well-documented among geriatric adults with cardiovascular disease(CVD);however,few studies have accounted for long-term cumulative depressive symptom exposure.This study determined the relationship between cumulative depressive symptoms and CVD.Methods Individual participant data were obtained from the China Health and Retirement Longitudinal Study(CHARLS)and Health and Retirement Study(HRS).Eligible participants had access to assessment information on depressive symptoms and had no history of CVD at baseline.Long-term cumulative depressive symptoms were estimated by calculating the area under the curve based on the Center for Epidemiological Studies Depression Scale.Results Herein,8,861 participants from CHARLS(mean age:58.58 years;male:48.6%)and 7,284 from HRS(60.94 years;35.0%)were enrolled.The median follow-up period was 5 years for the CHARLS and10 years for the HRS.Compared with the first quartile of cumulative depressive symptoms,the HRs(95%CI)in the fourth quartile were 1.73(1.48,2.02)for predicting CVD(P<0.001),1.83(1.52,2.19)for heart disease(P<0.001),1.53(95%CI:1.17,1.99)for stroke(P=0.002)in CHARLS.For HRS,the HRs(95%CI)were 1.41(95%CI:1.27,1.57;P<0.001),1.42(95%CI:1.26,1.59;P<0.001),and 1.30(95%CI:1.06,1.58;P=0.010)respectively.Strong dose-response relationships were observed,with similar results for the two cohorts.Conclusion Long-term cumulative depressive symptoms were significantly associated with incident CVD in middle-aged and older adults,providing insights into controlling long-term depressive symptoms to improve this cohort's health.展开更多
Drilling and blasting tunneling is a cyclic process in which tunnel rock undergoes repeated blast loading,affecting its dynamic characteristics,energy evolution,and damage progression.To explore the dynamic mechanical...Drilling and blasting tunneling is a cyclic process in which tunnel rock undergoes repeated blast loading,affecting its dynamic characteristics,energy evolution,and damage progression.To explore the dynamic mechanical properties and damage mechanisms of carbonaceous slate under cyclic impact loads of varying intensities,cyclic dynamic tests are conducted using a triaxial split Hopkinson pressure bar.This study analyzes the stress-strain relationship,energy damage evolution,and macro-to-micro failure characteristics.The results show that peak stress and strain are significantly influenced by impact intensity and the number of impacts.The initial dynamic stress is positively correlated with the impact intensity,but with more impact,the dynamic stress decreases while the peak strain increases.Energy evolution follows a pattern of"slow growthfluctuating growthrapid growth,"with the crack initiation stress and its proportion decreasing.CT and SEM analyses reveal that as the impact intensity increases,failure becomes more chaotic,the fracture volume increases,and the fracture mode shifts from interlayer and intergranular to through-layer and trans-granular fractures.These findings provide an experimental basis for soft rock tunnel stability analysis.展开更多
Background:The analgesic effects of multiple electroacupuncture(EA)sessions and single EA sessions differ significantly in pain management.Area 24b(A24b)of the anterior cingulate cortex(ACC)is crucial in pain processi...Background:The analgesic effects of multiple electroacupuncture(EA)sessions and single EA sessions differ significantly in pain management.Area 24b(A24b)of the anterior cingulate cortex(ACC)is crucial in pain processing.EA relieves pain by targeting and modulating the neuronal activity within this subregion.However,whether the cumulative effect of EA antinociception is connected to A24b mechanisms has remained unclear.Methods:In our study,we used the Complete Freund's Adjuvant(CFA)model to induce inflammatory pain and the Spared Nerve Injury(SNI)model to induce neuropathic pain,and adult male C57BL/6,FosTRAP,and FosTRAP:Ai9 mice were used as experimental subjects to investigate the cumulative effect of EA antinociception and whether multiple EA sessions and a single EA session regulate different neuronal populations in the A24b.Results:We observed that EA effectively alleviated pain in mice,with three EA sessions yielding superior analgesic effects compared to a single session.Using chemical genetics combined with FosCreER technology to activate EA-TRAPed cells in the A24b,we found that pain relief was more pronounced with three EA sessions.Moreover,chemogenetic inhibition of EA-TRAPed cells in the A24b reversed the analgesic effects of a single EA session but not those of three EA sessions.Fluorescent in situ hybridization results indicated that three EA sessions significantly increased the number of GABAergic neurons in the A24b compared with a single session.Additionally,retrograde tracing revealed that the A24b circuit that monosynaptically innervates EA-TRAPed cells included projections from the central lateral nucleus(CL),lateral mediodorsal thalamic nucleus(MDL),lateral habenula(LHb),dorsal raphe nucleus(DR),caudal linear nucleus of the raphe(CLi),dorsal tuberomamillary nucleus(DTM),periventricular hypothalamic nucleus(Pe)and hippocampal fields CA1,CA2,and CA3.These findings suggest that multiple EA sessions and single EA sessions activated different neuronal populations in the A24b.The enhanced analgesic effect of multiple EA sessions may be attributed to an increase in the proportion of GABAergic neurons within the A24b.Conclusions:Multiple and single EA sessions recruit distinct neuronal populations in A24b,with the stronger analgesic effect of repeated EA linked to a higher proportion of GABAergic neurons in this region.展开更多
Research on neutron-induced fission product yields of^(232)Th is crucial for understanding the competition between symmetric and asymmetric fission in actinide nuclei.However,obtaining complete isotopic yield distribu...Research on neutron-induced fission product yields of^(232)Th is crucial for understanding the competition between symmetric and asymmetric fission in actinide nuclei.However,obtaining complete isotopic yield distributions over a wide range of neutron energies remains a challenge.In this study,a Bayesian neural network model was developed to predict the independent(IND)and cumulative fission yields of^(232)Th under neutron irradiation at various incident energies.To address the limited availability of experimental data for the analysis of IND mass distributions,we substituted mass-number-based yields with the yields of specific isotopes.Furthermore,physical phenomena or quantities,such as the odd-even effect and isospin,were introduced as constraints to enhance the physical consistency of the predictions.The impact of these constraints was evaluated using mass-chain yield distributions and their dependence on energy.Incorporating physical constraints significantly improves the prediction accuracy,yielding more reliable and physically meaningful fission yield data for nuclear physics and reactor design applications.展开更多
This study developed a modeling methodology for statistical optimization-based geologic hazard susceptibility assessment,aiming to enhance the comprehensive performance and classification accuracy of the assessment mo...This study developed a modeling methodology for statistical optimization-based geologic hazard susceptibility assessment,aiming to enhance the comprehensive performance and classification accuracy of the assessment models.First,the cumulative probability method revealed that a low probability(15%)of geologic hazards between any two geologic hazard points occurred outside a buffer zone with a radius of 2297 m(i.e.,the distance threshold).The training dataset was established,consisting of negative samples(non-hazard points)randomly generated based on the distance threshold,positive samples(i.e.,historical hazards),and 13 conditioning factors.Then,models were built using five machine learning algorithms,namely random forest(RF),gradient boosting decision tree(GBDT),naive Bayes(NB),logistic regression(LR),and support vector machine(SVM).The comprehensive performance of the models was assessed using the area under the receiver operating characteristic curve(AUC)and overall accuracy(OA)as indicators,revealing that RF exhibited the best performance,with OA and AUC values of 2.7127 and 0.981,respectively.Furthermore,the machine learning models constructed by considering the distance threshold outperformed those built using the unoptimized dataset.The characteristic factors were ranked using the mutual information method,with their scores decreasing in the order of rainfall(0.1616),altitude(0.06),normalized difference vegetation index(NDVI;0.04),and distance from roads(0.03).Finally,the geologic hazard susceptibility classification was assessed using the natural breaks method combined with a clustering algorithm.The results indicate that the clustering algorithm exhibited higher classification accuracy than the natural breaks method.The findings of this study demonstrate that the proposed model optimization scheme can provide a scientific basis for the prevention and control of geologic hazards.展开更多
BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity va...BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity variables affect MDD.We hypothesize that high-level trait-and state-related stress-sensitivity factors may have different cumulative effects on the clinical symptoms and follow-up outcomes of MDD.AIM To investigate how stress-sensitivity factors added up and affected MDD clinical symptoms and follow-up results.METHODS In this prospective study,281 MDD patients were enrolled from a tertiary care setting.High-level stress-sensitivity factors were classified as trait anxiety,state anxiety,perceived stress,and neuroticism,with a total score in the top quartile of the research cohort.The cumulative effects of stress-sensitivity factors on cognitive dysfunction,disability and functional impairment,suicide risk,and depressive and anxiety symptoms were examined using an analysis of variance with linear trend analysis.Correlations were investigated further using multiple regression analysis.RESULTS Regarding high-level stress-sensitivity factors,53.40%of patients had at least one at baseline,and 29.61%had two or more.Four high-level stress-sensitivity components had significant cumulative impacts on MDD symptoms at baseline(all P<0.001).Perceived stress predicted the greatest effect sizes of state-related factors on depressive symptoms(partialη^(2)=0.153;standardizedβ=0.195;P<0.05).The follow-up outcomes were significantly impacted only by the high-level trait-related components,mainly when it came to depressive symptoms and suicide risk,which were predicted by trait anxiety and neuroticism,respectively(partialη^(2)=0.204 and 0.156;standardizedβ=0.247 and 0.392;P<0.05).CONCLUSION To enhance outcomes of MDD and lower the suicide risk,screening for stress-sensitivity factors and considering multifaceted measures,mainly focusing on trait-related ones,should be addressed clinically.展开更多
A typical Whipple shield consists of double-layered plates with a certain gap.The space debris impacts the outer plate and is broken into a debris cloud(shattered,molten,vaporized)with dispersed energy and momentum,wh...A typical Whipple shield consists of double-layered plates with a certain gap.The space debris impacts the outer plate and is broken into a debris cloud(shattered,molten,vaporized)with dispersed energy and momentum,which reduces the risk of penetrating the bulkhead.In the realm of hypervelocity impact,strain rate(>10^(5)s^(-1))effects are negligible,and fluid dynamics is employed to describe the impact process.Efficient numerical tools for precisely predicting the damage degree can greatly accelerate the design and optimization of advanced protective structures.Current hypervelocity impact research primarily focuses on the interaction between projectile and front plate and the movement of debris cloud.However,the damage mechanism of debris cloud impacts on rear plates-the critical threat component-remains underexplored owing to complex multi-physics processes and prohibitive computational costs.Existing approaches,ranging from semi-empirical equations to a machine learningbased ballistic limit prediction method,are constrained to binary penetration classification.Alternatively,the uneven data from experiments and simulations caused these methods to be ineffective when the projectile has irregular shapes and complicate flight attitude.Therefore,it is urgent to develop a new damage prediction method for predicting the rear plate damage,which can help to gain a deeper understanding of the damage mechanism.In this study,a machine learning(ML)method is developed to predict the damage distribution in the rear plate.Based on the unit velocity space,the discretized information of debris cloud and rear plate damage from rare simulation cases is used as input data for training the ML models,while the generalization ability for damage distribution prediction is tested by other simulation cases with different attack angles.The results demonstrate that the training and prediction accuracies using the Random Forest(RF)algorithm significantly surpass those using Artificial Neural Networks(ANNs)and Support Vector Machine(SVM).The RF-based model effectively identifies damage features in sparsely distributed debris cloud and cumulative effect.This study establishes an expandable new dataset that accommodates additional parameters to improve the prediction accuracy.Results demonstrate the model's ability to overcome data imbalance limitations through debris cloud features,enabling rapid and accurate rear plate damage prediction across wider scenarios with minimal data requirements.展开更多
Monte Carlo(MC) simulations have been performed to refine the estimation of the correction-toscaling exponent ω in the 2D φ^(4)model,which belongs to one of the most fundamental universality classes.If corrections h...Monte Carlo(MC) simulations have been performed to refine the estimation of the correction-toscaling exponent ω in the 2D φ^(4)model,which belongs to one of the most fundamental universality classes.If corrections have the form ∝ L^(-ω),then we find ω=1.546(30) andω=1.509(14) as the best estimates.These are obtained from the finite-size scaling of the susceptibility data in the range of linear lattice sizes L ∈[128,2048] at the critical value of the Binder cumulant and from the scaling of the corresponding pseudocritical couplings within L∈[64,2048].These values agree with several other MC estimates at the assumption of the power-law corrections and are comparable with the known results of the ε-expansion.In addition,we have tested the consistency with the scaling corrections of the form ∝ L^(-4/3),∝L^(-4/3)In L and ∝L^(-4/3)/ln L,which might be expected from some considerations of the renormalization group and Coulomb gas model.The latter option is consistent with our MC data.Our MC results served as a basis for a critical reconsideration of some earlier theoretical conjectures and scaling assumptions.In particular,we have corrected and refined our previous analysis by grouping Feynman diagrams.The renewed analysis gives ω≈4-d-2η as some approximation for spatial dimensions d <4,or ω≈1.5 in two dimensions.展开更多
Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves a...Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.展开更多
BACKGROUND Complications arising from the polyps in Peutz-Jeghers syndrome(PJS)have historically been addressed through surgical treatment.Enteroscopic poly-pectomy is hypothesized to reduce the risk of surgery in PJS...BACKGROUND Complications arising from the polyps in Peutz-Jeghers syndrome(PJS)have historically been addressed through surgical treatment.Enteroscopic poly-pectomy is hypothesized to reduce the risk of surgery in PJS.However,the optimal timing for polyp screening and preventive intervention using entero-scopic polypectomy remains uncertain.This is primarily due to the extremely low incidence of the condition and the paucity of data regarding the natural risk of requiring surgery and its age distribution in PJS patients.In order to develop recommendations on the appropriate timing of polyp screening and preventive intervention in PJS,a comprehensive understanding of the natural surgical risks AIM To investigate the natural surgical risks associated with polyps in PJS and to clarify their age distribution.METHODS A web-based open survey was launched to collect information from Chinese individuals suspected of having PJS.The questionnaire was distributed to the PJS instant messaging groups using a quick response code method.The data were analyzed using descriptive statistical methods,and the cumulative incidence of surgery was calculated using the Kaplan-Meier method.RESULTS Of the 442 patients enrolled,301(68.10%)had undergone 506 surgical procedures prior to enteroscopy or the survey deadline.Among the 506 surgical procedures,388(76.68%)were performed on patients aged between 6 and 25 years.The cumulative incidence rates of the first surgical procedure at 5,10,15,20,25,and 30 years of age were 5.0%(95%confidence interval[CI]:2.9%-7.0%),20.6%(95%CI:16.6%-24.4%),40.5%(95%CI:35.5%-45.1%),58.0%(95%CI:52.7%-62.7%),72.6%(95%CI:67.3%-77.0%),and 82.4%(95%CI:77.0%-86.5%),respectively.The primary indications for the first surgical procedures were intussusception(81.40%),obstruction(13.95%),and gas-trointestinal bleeding(4.65%).The cumulative incidence rates of requiring a second surgical procedure within 1,3,5,10 and 15 years following the first surgical procedure were 3.7%(95%CI:1.5%-5.8%),12.5%(95%CI:8.6%-16.2%),20.3%(95%CI:15.6%-24.8%),37.0%(95%CI:33.1%-45.3%),54.2%(95%CI:46.8%-60.5%),respectively.Patients who underwent their first surgical procedure at the age of nine years or younger presented an elevated risk of requiring a second surgical procedure(P<0.01).CONCLUSION Chinese patients with PJS have a high natural risk of undergoing surgery.Without preventive intervention,these procedures may become necessary at an early age and may be repeated.Early screening and regular surveillance,with preventive intervention if necessary,should commence at six years of age.展开更多
Background:Trunk lean angle is an underrepre sented biomechanical variable for modulating and redistributing lower extremity joint loading and potentially reducing the risk of running-related overuse injuries.The purp...Background:Trunk lean angle is an underrepre sented biomechanical variable for modulating and redistributing lower extremity joint loading and potentially reducing the risk of running-related overuse injuries.The purpose of this study was to systematically alter the trunk lean angle in distance running using an auditory real-time feedback approach and to derive dose-response relationships between sagittal plane trunk lean angle and lower extremity(cumulative)joint loading to guide overuse load management in clinical practice.Methods:Thirty recreational runners(15 males and 15 females)ran at a constant speed of 2.5 m/s at 5 systematically varied trunk lean conditions on a force-instrumented treadmill while kinematic and kinetic data were captured.Results:A change in trunk lean angle from-2°(extension)to 28°(flexion)resulted in a systematic increase in stance phase angular impulse,cumulative impulse,and peak moment at the hip joint in the sagittal and transversal plane.In contrast,a systematic decrease in these parameters at the knee j oint in the sagittal plane and the hip joint in the frontal plane was found(p<0.001).Linear fitting revealed that with every degree of anterior trunk leaning,the cumulative hip joint extension loading increases by 3.26 Nm·s/kg/1000 m,while simultaneously decreasing knee joint extension loading by 1.08 Nm·s/kg/1000 m.Conclusion:Trunk leaning can reduce knee joint loading and hip joint abduction loading,at the cost of hip joint loading in the sagittal and transversal planes during distance running.Modulating lower extremity joint loading by altering trunk lean angle is an effective strategy to redistribute joint load between/within the knee and hip joints.When implementing anterior trunk leaning in clinical practice,the increased demands on the hip musculature,dynamic stability,and the potential trade-off with running economy should be considered.展开更多
As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wi...As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wind speed correlation,a multi-scenario PLF calculation method that combines random sampling and segmented discrete wind farm power was proposed.Firstly,based on constructing discrete scenes of wind farms,the Nataf transform is used to handle the correlation between wind speeds.Then,the random sampling method determines the output probability of discrete wind power scenarios when wind speed exhibits correlation.Finally,the PLF calculation results of each scenario areweighted and superimposed following the total probability formula to obtain the final power flow calculation result.Verified in the IEEE standard node system,the absolute percent error(APE)for the mean and standard deviation(SD)of the node voltages and branch active power are all within 1%,and the average root mean square(AMSR)values of the probability curves are all less than 1%.展开更多
In the civil and mining industries,bolts are critical components of support systems,playing a vital role in ensuring their stability.Glass fibre reinforced polymer(GFRP)bolts are widely used because they are corrosion...In the civil and mining industries,bolts are critical components of support systems,playing a vital role in ensuring their stability.Glass fibre reinforced polymer(GFRP)bolts are widely used because they are corrosion-resistant and cost-effective.However,the damage mechanisms of GFRP bolts under blasting dynamic loads are still unclear,especially compared to metal bolts.This study investigates the cumulative damage of fully grouted GFRP bolts under blasting dynamic loads.The maximum axial stress at the tails of the bolts is defined as the damage variable,based on the failure characteristics of GFRP bolts.By combining this with Miner's cumulative damage theory,a comprehensive theoretical and numerical model is established to calculate cumulative damage.Field data collected from the Jinchuan No.3 Mining Area,including GFRP bolts parameters and blasting vibration data are used for further analysis of cumulative damage in fully grouted GFRP bolts.Results indicate that with an increasing number of blasts,axial stress increases in all parts of GFRP bolts.The tail exhibits the most significant rise,with stress extending deeper into the anchorage zone.Cumulative damage follows an exponential trend with the number of blasts,although the incremental damage per blast decelerates over time.Higher dynamic load intensities accelerate damage accumulation,leading to an exponential decline in the maximum loading cycles before failure.Additionally,stronger surrounding rock and grout mitigate damage accumulation,with the effect of surrounding rock strength being more pronounced than that of grout.In contrast,the maximum axial stress of metal bolts increases quickly to a certain point and then stabilizes.This shows a clear difference between GFRP and metal bolts.This study presents a new cumulative damage theory that underpins the design of GFRP bolt support systems under blasting conditions,identifies key damage factors,and suggests mitigation measures to enhance system stability.展开更多
Objective:This study aimed to investigate the longitudinal trajectories of cumulative fluid balance(CFB)in intensive care unit(ICU)patients and analyze the relationship between different trajectory groups and the occu...Objective:This study aimed to investigate the longitudinal trajectories of cumulative fluid balance(CFB)in intensive care unit(ICU)patients and analyze the relationship between different trajectory groups and the occurrence of pressure injuries(PIs).Methods:In this retrospective longitudinal study,we obtained health-related data from the Medical Information Mart for Intensive Care IV database,including sociodemographic,disease-related variables,and ICU treatment variables.The daily CFB adjusted for body weight was calculated,and the occurrence of PIs during the ICU stay was recorded.A group-based trajectory model was used to explore the different CFB trajectories.Binary logistic regression was used to analyze the relationship between the CFB trajectory group and PIs.Results:Among the 4,294 included participants,we identified four distinct trajectories of CFB in ICU patients:the rapid accumulation group(12.5%),the slow accumulation group(28.5%),the neutral balance group(41.7%),and the negative decrease group(17.3%).After adjusting for some sociodemographic,disease-related variables,and ICU treatment variables,the rapid accumulation group had an OR of 1.63(95%CI:1.30,2.04)for all stages of PIs and an OR of 1.36(95%CI:1.08,1.72)for stage II or higher PIs compared to the neutral balance group.Conclusions:Four unique trajectories of CFB were identified among patients in the ICU,including rapid accumulation,slow accumulation,neutral balance,and negative decrease.Rapid accumulation independently increased the risk of PIs during ICU stay.展开更多
In November 2024,the Global Solar Council announced that the world cumulative solar capacity reached 2 terawatts,twice as much as in mid-2022,clearly showing that solar energy is set to lead the energy transition.
Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-in...Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-induced anxiety but also complex challenges such as interpersonal adaptation difficulties and career planning confusion.Traditional“problem-oriented”intervention models have shown limitations in responsiveness and adaptability,often only passively addressing existing psychological crises rather than preventing them in advance.This study aims to explore an AI-powered“positive psychology”proactive intervention model through developing an intelligent system.The system automatically collects,filters,and personalizes recommendations for positive activities on campus.Using a randomized controlled trial design,we conducted an 8-week intervention study involving 126 college students at a university.The study found that AI-based“campus positive activity”recommendations effectively boost students’positive emotions and promote psychological capital development through cumulative micro-interventions.This provides universities with empirical evidence and innovative methods to implement low-cost,efficient,and scalable mental health promotion programs through smart technology.展开更多
基金supported by the Science and Technology Research Project to Henan Provincial Department of Natural Resources(Henan Natural Resources Letter[2019]373–10)。
文摘The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining.The environmental impact of long-term mining activities cannot be ignored.It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution.Taking the Taowanbeigou River Basin in the mine concentration area as the research object,the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method,potential ecological risk assessment method and geoaccumulation index method.On this basis,the cumulative exceeding years of specific heavy metals were predicted by using the early warning model.The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate,and the single element Cd is the main ecological risk factor,with a contribution rate of 53.6%.The overall cumulative degrees of Cu and Pb in the soil are“none-moderate”,Zn and Cd are moderate,Mo has reached an extremely strong cumulative level,Hg,As and Cr risks are not obvious,and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg.According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard,the locations over standard rates of Cu,Zn and Cd will exceed 78%in 90years,and the over standard rate of Pb will reach approximately 57%in 200 years.The cumulative exceeding standard periods of As,Cr and Hg are generally long,which basically indicates that these elements do not pose a significant potential threat to the ecological environment.Mining activities will accelerate the accumulation of heavy metals in soil.With the continuous development of mining activities,the potential pollution risk of heavy metals in the soil of mining areas will also increase.
基金Supported by the National Natural Science Foundation of China (Nos.40901139, 41025005, and 30821140538)the Knowledge Innovation Program of the Chinese Academy of Sciences (No.ISSASIP0708)
文摘Oiltea camellia （Camellia oleifera Abel.）, an aluminium （Al） hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application and the characteristics of Al uptake and accumulation were investigated using laboratory and field experiments. The growth of oiltea camellia seedlings in the nutrient solution tended to be stimulated by addition of Al. Results of the field experiment showed that oiltea camellia accumulated 11 000 mg kg-1 Al in leaves within 10 months, and the average rate of Al accumulation in new leaves was about 1100 mg kg-1 month-1; however, the monthly rate varied and was highest in spring and autumn. The results of the laboratory experiment on Al uptake by oiltea camellia seedlings in CaC12 solutions with various forms of Al showed that large amounts of Al supplied as Al3＋ and Al complexes Al-malate （1：1） and Al-F （1：1） were infiuxed into oiltea camellia roots, whereas Al supplied as Al-citrate （1：1）, Al-F （1：6）, Al-oxalate （1：3）, and Al-oxalate （1：1） complexes exhibited low affinity to oiltea camellia roots. The kinetics of Al3＋ cumulative uptake in excised roots and intact plants showed a biphasic pattern, with an initial rapid phase followed by a slow phase. The Al cumulative uptake was unaffected by low temperature, which indicated that Al uptake in oiltea camellia was a passive process. The efficient influx of Al into the roots and the high transport rate in specific seasons were presumed to account for the plentiful Al accumulation in leaves of oiltea camellia.
文摘Using cumulative quantum mechanics(CQM)and the method of generalized mathematical transfer(MGMT),we analytically study quantum nanometer cumulative-dissipative structures(CDS)and the forces arising within them,which focus nanostructures into regular,fractalized systems—cumulative-dissipative standing hydrogen-like excitons(atoms,molecules,lines,surfaces)and flickering crystals we discovered for the first time.(1)We demonstrate the formation of Vysikaylo standing excitons on permittivity[ε(r)]inhomogeneities in diamond in the nanoscale regions of foreign atoms.(2)For the first time,we solve the problem of measuringε(r)profiles in inhomogeneous nanoscale structures using Raman spectra(RS)[with an accuracy of up to 99.9%forε(r)and a step of up to 0.3 nm depending on the distance from the impurity atom(boron)].(3)Using our theory of Vysikaylo standing excitons,we explain the experimental observation of the degeneracy of electron spectra in standing excitons with respect to the principal quantum number n and n−1/2.By comparing the theory and experimental observations of RS in diamonds doped with boron,we solve the problem(that we formulated previously)between the de Broglie hypothesis and the classical new quantum mechanics of Dirac(which limits the-functions,or prohibits symmetric de Broglie half-waves in spherically and cylindrically symmetric quantum resonators)in favor of the de Broglie hypothesis.Based on the works of Wannier and Mott,we refine the definition of the permittivity of nanocrystals as a coefficient in electric potentials[U(r)→ε(r)U(r)]rather than electric fields[D(r)=ε(r)E(r)].We construct the most complete theory of the chemical doping of crystals(using the example of group IV crystals doped with group III and V atoms).For the first time,we raise the question of the quantum cleaning of crystals or the accumulation of dopant atoms.
文摘Consideration is given to results of experimental and theoretical investigations how alpha-epsilon phase transition in the unalloyed iron and the 30 KhGSA steel and its absence in the austenitic 12Kh18N10T stainless steel influence processes under explosive deformation of spheres made of these materials.Polymorphous transition is shown to significantly effect on:amount of explosion-products energy transferred to a sphere,evolution of the converging-wave structure and its parameters,profiles of stress wave and temperature T(R,t)for some Lagrangian particles along the sphere radius,character of energy cumulation under spherical convergence of waves.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(2021A1515011629)Construction of High-level University of Guangdong(G623330580and G621331128)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2019)。
文摘Objective Elevated depressive symptoms are well-documented among geriatric adults with cardiovascular disease(CVD);however,few studies have accounted for long-term cumulative depressive symptom exposure.This study determined the relationship between cumulative depressive symptoms and CVD.Methods Individual participant data were obtained from the China Health and Retirement Longitudinal Study(CHARLS)and Health and Retirement Study(HRS).Eligible participants had access to assessment information on depressive symptoms and had no history of CVD at baseline.Long-term cumulative depressive symptoms were estimated by calculating the area under the curve based on the Center for Epidemiological Studies Depression Scale.Results Herein,8,861 participants from CHARLS(mean age:58.58 years;male:48.6%)and 7,284 from HRS(60.94 years;35.0%)were enrolled.The median follow-up period was 5 years for the CHARLS and10 years for the HRS.Compared with the first quartile of cumulative depressive symptoms,the HRs(95%CI)in the fourth quartile were 1.73(1.48,2.02)for predicting CVD(P<0.001),1.83(1.52,2.19)for heart disease(P<0.001),1.53(95%CI:1.17,1.99)for stroke(P=0.002)in CHARLS.For HRS,the HRs(95%CI)were 1.41(95%CI:1.27,1.57;P<0.001),1.42(95%CI:1.26,1.59;P<0.001),and 1.30(95%CI:1.06,1.58;P=0.010)respectively.Strong dose-response relationships were observed,with similar results for the two cohorts.Conclusion Long-term cumulative depressive symptoms were significantly associated with incident CVD in middle-aged and older adults,providing insights into controlling long-term depressive symptoms to improve this cohort's health.
基金support from the Joint Funds of the National Natural Science Foundation of China(Grant No.U23A2060)the National Natural Science Foundation of China(Grant Nos.42177143 and 52474150).
文摘Drilling and blasting tunneling is a cyclic process in which tunnel rock undergoes repeated blast loading,affecting its dynamic characteristics,energy evolution,and damage progression.To explore the dynamic mechanical properties and damage mechanisms of carbonaceous slate under cyclic impact loads of varying intensities,cyclic dynamic tests are conducted using a triaxial split Hopkinson pressure bar.This study analyzes the stress-strain relationship,energy damage evolution,and macro-to-micro failure characteristics.The results show that peak stress and strain are significantly influenced by impact intensity and the number of impacts.The initial dynamic stress is positively correlated with the impact intensity,but with more impact,the dynamic stress decreases while the peak strain increases.Energy evolution follows a pattern of"slow growthfluctuating growthrapid growth,"with the crack initiation stress and its proportion decreasing.CT and SEM analyses reveal that as the impact intensity increases,failure becomes more chaotic,the fracture volume increases,and the fracture mode shifts from interlayer and intergranular to through-layer and trans-granular fractures.These findings provide an experimental basis for soft rock tunnel stability analysis.
基金The National Natural Science Fund of China(82374561,82174490,81873360)the Research Project of Zhejiang Chinese Medical University(2022JKZKTS44,2022FSYYZZ07)the Zhejiang Medical and Health Science and Technology Program(2021RC098)。
文摘Background:The analgesic effects of multiple electroacupuncture(EA)sessions and single EA sessions differ significantly in pain management.Area 24b(A24b)of the anterior cingulate cortex(ACC)is crucial in pain processing.EA relieves pain by targeting and modulating the neuronal activity within this subregion.However,whether the cumulative effect of EA antinociception is connected to A24b mechanisms has remained unclear.Methods:In our study,we used the Complete Freund's Adjuvant(CFA)model to induce inflammatory pain and the Spared Nerve Injury(SNI)model to induce neuropathic pain,and adult male C57BL/6,FosTRAP,and FosTRAP:Ai9 mice were used as experimental subjects to investigate the cumulative effect of EA antinociception and whether multiple EA sessions and a single EA session regulate different neuronal populations in the A24b.Results:We observed that EA effectively alleviated pain in mice,with three EA sessions yielding superior analgesic effects compared to a single session.Using chemical genetics combined with FosCreER technology to activate EA-TRAPed cells in the A24b,we found that pain relief was more pronounced with three EA sessions.Moreover,chemogenetic inhibition of EA-TRAPed cells in the A24b reversed the analgesic effects of a single EA session but not those of three EA sessions.Fluorescent in situ hybridization results indicated that three EA sessions significantly increased the number of GABAergic neurons in the A24b compared with a single session.Additionally,retrograde tracing revealed that the A24b circuit that monosynaptically innervates EA-TRAPed cells included projections from the central lateral nucleus(CL),lateral mediodorsal thalamic nucleus(MDL),lateral habenula(LHb),dorsal raphe nucleus(DR),caudal linear nucleus of the raphe(CLi),dorsal tuberomamillary nucleus(DTM),periventricular hypothalamic nucleus(Pe)and hippocampal fields CA1,CA2,and CA3.These findings suggest that multiple EA sessions and single EA sessions activated different neuronal populations in the A24b.The enhanced analgesic effect of multiple EA sessions may be attributed to an increase in the proportion of GABAergic neurons within the A24b.Conclusions:Multiple and single EA sessions recruit distinct neuronal populations in A24b,with the stronger analgesic effect of repeated EA linked to a higher proportion of GABAergic neurons in this region.
基金supported by the National Natural Science Foundation of China(Nos.12247126 and 12375123)Henan Postdoctoral Foundation(No.HN2024013)the Natural Science Foundation of Henan Province(No.242300421048)。
文摘Research on neutron-induced fission product yields of^(232)Th is crucial for understanding the competition between symmetric and asymmetric fission in actinide nuclei.However,obtaining complete isotopic yield distributions over a wide range of neutron energies remains a challenge.In this study,a Bayesian neural network model was developed to predict the independent(IND)and cumulative fission yields of^(232)Th under neutron irradiation at various incident energies.To address the limited availability of experimental data for the analysis of IND mass distributions,we substituted mass-number-based yields with the yields of specific isotopes.Furthermore,physical phenomena or quantities,such as the odd-even effect and isospin,were introduced as constraints to enhance the physical consistency of the predictions.The impact of these constraints was evaluated using mass-chain yield distributions and their dependence on energy.Incorporating physical constraints significantly improves the prediction accuracy,yielding more reliable and physically meaningful fission yield data for nuclear physics and reactor design applications.
基金supported by a project entitled Loess Plateau Region-Watershed-Slope Geological Hazard Multi-Scale Collaborative Intelligent Early Warning System of the National Key R&D Program of China(2022YFC3003404)a project of the Shaanxi Youth Science and Technology Star(2021KJXX-87)public welfare geological survey projects of Shaanxi Institute of Geologic Survey(20180301,201918,202103,and 202413)。
文摘This study developed a modeling methodology for statistical optimization-based geologic hazard susceptibility assessment,aiming to enhance the comprehensive performance and classification accuracy of the assessment models.First,the cumulative probability method revealed that a low probability(15%)of geologic hazards between any two geologic hazard points occurred outside a buffer zone with a radius of 2297 m(i.e.,the distance threshold).The training dataset was established,consisting of negative samples(non-hazard points)randomly generated based on the distance threshold,positive samples(i.e.,historical hazards),and 13 conditioning factors.Then,models were built using five machine learning algorithms,namely random forest(RF),gradient boosting decision tree(GBDT),naive Bayes(NB),logistic regression(LR),and support vector machine(SVM).The comprehensive performance of the models was assessed using the area under the receiver operating characteristic curve(AUC)and overall accuracy(OA)as indicators,revealing that RF exhibited the best performance,with OA and AUC values of 2.7127 and 0.981,respectively.Furthermore,the machine learning models constructed by considering the distance threshold outperformed those built using the unoptimized dataset.The characteristic factors were ranked using the mutual information method,with their scores decreasing in the order of rainfall(0.1616),altitude(0.06),normalized difference vegetation index(NDVI;0.04),and distance from roads(0.03).Finally,the geologic hazard susceptibility classification was assessed using the natural breaks method combined with a clustering algorithm.The results indicate that the clustering algorithm exhibited higher classification accuracy than the natural breaks method.The findings of this study demonstrate that the proposed model optimization scheme can provide a scientific basis for the prevention and control of geologic hazards.
基金Supported by Science and Technology Innovation 2030-Major Projects,No.2021ZD0202000National Key Research and Development Program of China,No.2019YFA0706200+2 种基金National Natural Science Foundation of China,No.82371535Science and Technology Innovation Program of Hunan Province,No.2023RC3083Fundamental Research Funds for the Central Universities of Central South University,No.2023ZZTS0838.
文摘BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity variables affect MDD.We hypothesize that high-level trait-and state-related stress-sensitivity factors may have different cumulative effects on the clinical symptoms and follow-up outcomes of MDD.AIM To investigate how stress-sensitivity factors added up and affected MDD clinical symptoms and follow-up results.METHODS In this prospective study,281 MDD patients were enrolled from a tertiary care setting.High-level stress-sensitivity factors were classified as trait anxiety,state anxiety,perceived stress,and neuroticism,with a total score in the top quartile of the research cohort.The cumulative effects of stress-sensitivity factors on cognitive dysfunction,disability and functional impairment,suicide risk,and depressive and anxiety symptoms were examined using an analysis of variance with linear trend analysis.Correlations were investigated further using multiple regression analysis.RESULTS Regarding high-level stress-sensitivity factors,53.40%of patients had at least one at baseline,and 29.61%had two or more.Four high-level stress-sensitivity components had significant cumulative impacts on MDD symptoms at baseline(all P<0.001).Perceived stress predicted the greatest effect sizes of state-related factors on depressive symptoms(partialη^(2)=0.153;standardizedβ=0.195;P<0.05).The follow-up outcomes were significantly impacted only by the high-level trait-related components,mainly when it came to depressive symptoms and suicide risk,which were predicted by trait anxiety and neuroticism,respectively(partialη^(2)=0.204 and 0.156;standardizedβ=0.247 and 0.392;P<0.05).CONCLUSION To enhance outcomes of MDD and lower the suicide risk,screening for stress-sensitivity factors and considering multifaceted measures,mainly focusing on trait-related ones,should be addressed clinically.
基金supported by National Natural Science Foundation of China(Grant No.12432018,12372346)the Innovative Research Groups of the National Natural Science Foundation of China(Grant No.12221002).
文摘A typical Whipple shield consists of double-layered plates with a certain gap.The space debris impacts the outer plate and is broken into a debris cloud(shattered,molten,vaporized)with dispersed energy and momentum,which reduces the risk of penetrating the bulkhead.In the realm of hypervelocity impact,strain rate(>10^(5)s^(-1))effects are negligible,and fluid dynamics is employed to describe the impact process.Efficient numerical tools for precisely predicting the damage degree can greatly accelerate the design and optimization of advanced protective structures.Current hypervelocity impact research primarily focuses on the interaction between projectile and front plate and the movement of debris cloud.However,the damage mechanism of debris cloud impacts on rear plates-the critical threat component-remains underexplored owing to complex multi-physics processes and prohibitive computational costs.Existing approaches,ranging from semi-empirical equations to a machine learningbased ballistic limit prediction method,are constrained to binary penetration classification.Alternatively,the uneven data from experiments and simulations caused these methods to be ineffective when the projectile has irregular shapes and complicate flight attitude.Therefore,it is urgent to develop a new damage prediction method for predicting the rear plate damage,which can help to gain a deeper understanding of the damage mechanism.In this study,a machine learning(ML)method is developed to predict the damage distribution in the rear plate.Based on the unit velocity space,the discretized information of debris cloud and rear plate damage from rare simulation cases is used as input data for training the ML models,while the generalization ability for damage distribution prediction is tested by other simulation cases with different attack angles.The results demonstrate that the training and prediction accuracies using the Random Forest(RF)algorithm significantly surpass those using Artificial Neural Networks(ANNs)and Support Vector Machine(SVM).The RF-based model effectively identifies damage features in sparsely distributed debris cloud and cumulative effect.This study establishes an expandable new dataset that accommodates additional parameters to improve the prediction accuracy.Results demonstrate the model's ability to overcome data imbalance limitations through debris cloud features,enabling rapid and accurate rear plate damage prediction across wider scenarios with minimal data requirements.
文摘Monte Carlo(MC) simulations have been performed to refine the estimation of the correction-toscaling exponent ω in the 2D φ^(4)model,which belongs to one of the most fundamental universality classes.If corrections have the form ∝ L^(-ω),then we find ω=1.546(30) andω=1.509(14) as the best estimates.These are obtained from the finite-size scaling of the susceptibility data in the range of linear lattice sizes L ∈[128,2048] at the critical value of the Binder cumulant and from the scaling of the corresponding pseudocritical couplings within L∈[64,2048].These values agree with several other MC estimates at the assumption of the power-law corrections and are comparable with the known results of the ε-expansion.In addition,we have tested the consistency with the scaling corrections of the form ∝ L^(-4/3),∝L^(-4/3)In L and ∝L^(-4/3)/ln L,which might be expected from some considerations of the renormalization group and Coulomb gas model.The latter option is consistent with our MC data.Our MC results served as a basis for a critical reconsideration of some earlier theoretical conjectures and scaling assumptions.In particular,we have corrected and refined our previous analysis by grouping Feynman diagrams.The renewed analysis gives ω≈4-d-2η as some approximation for spatial dimensions d <4,or ω≈1.5 in two dimensions.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102480,52278543 and 51978660)Natural Science Foundation of Jiangsu Province(Grant No.BK20231489)。
文摘Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition.
文摘BACKGROUND Complications arising from the polyps in Peutz-Jeghers syndrome(PJS)have historically been addressed through surgical treatment.Enteroscopic poly-pectomy is hypothesized to reduce the risk of surgery in PJS.However,the optimal timing for polyp screening and preventive intervention using entero-scopic polypectomy remains uncertain.This is primarily due to the extremely low incidence of the condition and the paucity of data regarding the natural risk of requiring surgery and its age distribution in PJS patients.In order to develop recommendations on the appropriate timing of polyp screening and preventive intervention in PJS,a comprehensive understanding of the natural surgical risks AIM To investigate the natural surgical risks associated with polyps in PJS and to clarify their age distribution.METHODS A web-based open survey was launched to collect information from Chinese individuals suspected of having PJS.The questionnaire was distributed to the PJS instant messaging groups using a quick response code method.The data were analyzed using descriptive statistical methods,and the cumulative incidence of surgery was calculated using the Kaplan-Meier method.RESULTS Of the 442 patients enrolled,301(68.10%)had undergone 506 surgical procedures prior to enteroscopy or the survey deadline.Among the 506 surgical procedures,388(76.68%)were performed on patients aged between 6 and 25 years.The cumulative incidence rates of the first surgical procedure at 5,10,15,20,25,and 30 years of age were 5.0%(95%confidence interval[CI]:2.9%-7.0%),20.6%(95%CI:16.6%-24.4%),40.5%(95%CI:35.5%-45.1%),58.0%(95%CI:52.7%-62.7%),72.6%(95%CI:67.3%-77.0%),and 82.4%(95%CI:77.0%-86.5%),respectively.The primary indications for the first surgical procedures were intussusception(81.40%),obstruction(13.95%),and gas-trointestinal bleeding(4.65%).The cumulative incidence rates of requiring a second surgical procedure within 1,3,5,10 and 15 years following the first surgical procedure were 3.7%(95%CI:1.5%-5.8%),12.5%(95%CI:8.6%-16.2%),20.3%(95%CI:15.6%-24.8%),37.0%(95%CI:33.1%-45.3%),54.2%(95%CI:46.8%-60.5%),respectively.Patients who underwent their first surgical procedure at the age of nine years or younger presented an elevated risk of requiring a second surgical procedure(P<0.01).CONCLUSION Chinese patients with PJS have a high natural risk of undergoing surgery.Without preventive intervention,these procedures may become necessary at an early age and may be repeated.Early screening and regular surveillance,with preventive intervention if necessary,should commence at six years of age.
文摘Background:Trunk lean angle is an underrepre sented biomechanical variable for modulating and redistributing lower extremity joint loading and potentially reducing the risk of running-related overuse injuries.The purpose of this study was to systematically alter the trunk lean angle in distance running using an auditory real-time feedback approach and to derive dose-response relationships between sagittal plane trunk lean angle and lower extremity(cumulative)joint loading to guide overuse load management in clinical practice.Methods:Thirty recreational runners(15 males and 15 females)ran at a constant speed of 2.5 m/s at 5 systematically varied trunk lean conditions on a force-instrumented treadmill while kinematic and kinetic data were captured.Results:A change in trunk lean angle from-2°(extension)to 28°(flexion)resulted in a systematic increase in stance phase angular impulse,cumulative impulse,and peak moment at the hip joint in the sagittal and transversal plane.In contrast,a systematic decrease in these parameters at the knee j oint in the sagittal plane and the hip joint in the frontal plane was found(p<0.001).Linear fitting revealed that with every degree of anterior trunk leaning,the cumulative hip joint extension loading increases by 3.26 Nm·s/kg/1000 m,while simultaneously decreasing knee joint extension loading by 1.08 Nm·s/kg/1000 m.Conclusion:Trunk leaning can reduce knee joint loading and hip joint abduction loading,at the cost of hip joint loading in the sagittal and transversal planes during distance running.Modulating lower extremity joint loading by altering trunk lean angle is an effective strategy to redistribute joint load between/within the knee and hip joints.When implementing anterior trunk leaning in clinical practice,the increased demands on the hip musculature,dynamic stability,and the potential trade-off with running economy should be considered.
基金supported by Basic Science Research Program through the National Natural Science Foundation of China(Grant No.61867003).
文摘As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wind speed correlation,a multi-scenario PLF calculation method that combines random sampling and segmented discrete wind farm power was proposed.Firstly,based on constructing discrete scenes of wind farms,the Nataf transform is used to handle the correlation between wind speeds.Then,the random sampling method determines the output probability of discrete wind power scenarios when wind speed exhibits correlation.Finally,the PLF calculation results of each scenario areweighted and superimposed following the total probability formula to obtain the final power flow calculation result.Verified in the IEEE standard node system,the absolute percent error(APE)for the mean and standard deviation(SD)of the node voltages and branch active power are all within 1%,and the average root mean square(AMSR)values of the probability curves are all less than 1%.
基金funded by the National Natural Science Foundation of China(No.51974206)the Hubei Province Safety Production Special Fund Science and Technology Project(No.KJZX202007007).
文摘In the civil and mining industries,bolts are critical components of support systems,playing a vital role in ensuring their stability.Glass fibre reinforced polymer(GFRP)bolts are widely used because they are corrosion-resistant and cost-effective.However,the damage mechanisms of GFRP bolts under blasting dynamic loads are still unclear,especially compared to metal bolts.This study investigates the cumulative damage of fully grouted GFRP bolts under blasting dynamic loads.The maximum axial stress at the tails of the bolts is defined as the damage variable,based on the failure characteristics of GFRP bolts.By combining this with Miner's cumulative damage theory,a comprehensive theoretical and numerical model is established to calculate cumulative damage.Field data collected from the Jinchuan No.3 Mining Area,including GFRP bolts parameters and blasting vibration data are used for further analysis of cumulative damage in fully grouted GFRP bolts.Results indicate that with an increasing number of blasts,axial stress increases in all parts of GFRP bolts.The tail exhibits the most significant rise,with stress extending deeper into the anchorage zone.Cumulative damage follows an exponential trend with the number of blasts,although the incremental damage per blast decelerates over time.Higher dynamic load intensities accelerate damage accumulation,leading to an exponential decline in the maximum loading cycles before failure.Additionally,stronger surrounding rock and grout mitigate damage accumulation,with the effect of surrounding rock strength being more pronounced than that of grout.In contrast,the maximum axial stress of metal bolts increases quickly to a certain point and then stabilizes.This shows a clear difference between GFRP and metal bolts.This study presents a new cumulative damage theory that underpins the design of GFRP bolt support systems under blasting conditions,identifies key damage factors,and suggests mitigation measures to enhance system stability.
文摘Objective:This study aimed to investigate the longitudinal trajectories of cumulative fluid balance(CFB)in intensive care unit(ICU)patients and analyze the relationship between different trajectory groups and the occurrence of pressure injuries(PIs).Methods:In this retrospective longitudinal study,we obtained health-related data from the Medical Information Mart for Intensive Care IV database,including sociodemographic,disease-related variables,and ICU treatment variables.The daily CFB adjusted for body weight was calculated,and the occurrence of PIs during the ICU stay was recorded.A group-based trajectory model was used to explore the different CFB trajectories.Binary logistic regression was used to analyze the relationship between the CFB trajectory group and PIs.Results:Among the 4,294 included participants,we identified four distinct trajectories of CFB in ICU patients:the rapid accumulation group(12.5%),the slow accumulation group(28.5%),the neutral balance group(41.7%),and the negative decrease group(17.3%).After adjusting for some sociodemographic,disease-related variables,and ICU treatment variables,the rapid accumulation group had an OR of 1.63(95%CI:1.30,2.04)for all stages of PIs and an OR of 1.36(95%CI:1.08,1.72)for stage II or higher PIs compared to the neutral balance group.Conclusions:Four unique trajectories of CFB were identified among patients in the ICU,including rapid accumulation,slow accumulation,neutral balance,and negative decrease.Rapid accumulation independently increased the risk of PIs during ICU stay.
文摘In November 2024,the Global Solar Council announced that the world cumulative solar capacity reached 2 terawatts,twice as much as in mid-2022,clearly showing that solar energy is set to lead the energy transition.
文摘Higher education is transitioning from mass expansion to high-quality development.In this process,mental health issues among college students have become increasingly prominent,encompassing not only academic stress-induced anxiety but also complex challenges such as interpersonal adaptation difficulties and career planning confusion.Traditional“problem-oriented”intervention models have shown limitations in responsiveness and adaptability,often only passively addressing existing psychological crises rather than preventing them in advance.This study aims to explore an AI-powered“positive psychology”proactive intervention model through developing an intelligent system.The system automatically collects,filters,and personalizes recommendations for positive activities on campus.Using a randomized controlled trial design,we conducted an 8-week intervention study involving 126 college students at a university.The study found that AI-based“campus positive activity”recommendations effectively boost students’positive emotions and promote psychological capital development through cumulative micro-interventions.This provides universities with empirical evidence and innovative methods to implement low-cost,efficient,and scalable mental health promotion programs through smart technology.
