Geological exploration cores obtained from shale gas wells several kilometers deep often show different height-diameter ratios(H/D)because of complex geological conditions(core disking or developed fractures),which ma...Geological exploration cores obtained from shale gas wells several kilometers deep often show different height-diameter ratios(H/D)because of complex geological conditions(core disking or developed fractures),which makes further standard specimen preparation for mechanical evaluation of reservoirs difficult.In multi-cluster hydraulic fracturing,shale reservoirs between planes of hydraulic fractures with different lengths could be simplified to have different H/D ratios.Discovering the effect of H/D on the mechanical characteristics of shale specimens with different bedding orientations will support mechanical evaluation tests of reservoirs based on disked geological cores and help to optimize multicluster fracturing programs.In this study,we performed uniaxial compression tests and acoustic emission(AE)monitoring on cylindrical Longmaxi shale specimens under five bedding orientations and four H/D ratios.The experimental results showed that both the H/D-dependent mechanical properties and AE parameters demonstrated significant anisotropy.Increasing H/D did not change the uniaxial compressive strength(UCS)evolution versus bedding orientation,demonstrating a V-shaped relationship,but enhanced the curve shape.The stress level of crack damage for the specimens significantly increased with increasing H/D,excluding the specimens with a bedding orientation of 0°.With increasing H/D,the cumulative AE counts of the specimens with each bedding orientation tended to exhibit a stepped jump against the loading time.The proportion of low-average-frequency AE signals(below 100 kHz)in specimens with bedding orientations of 45°and 60°increased to over 70%by increasing H/D,but it only increased to 40%in specimens with bedding orientations of 0°,30°,and 90°.Finally,an empirical model that can reveal the effect of H/D on anisotropic UCS of shale reservoir was proposed,the anisotropic proportion of tensile and shear failure cracks in specimens under four H/D ratios was classified based on the AE data,and the effect of H/D on the anisotropic crack growth of specimens was discussed.展开更多
Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study invest...Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study investigates their coupled effects using inclinedflume experiments and Discrete Element Method(DEM)simulations,covering three gravel sizes(2-5 mm,5-7 mm,7-10 mm)and four ice-content levels(0%,20%,40%,60%).Run-out distance,velocity,energy components,flow regime(Savage number),and segregation indexαwere quantified.Increasing ice content significantly enhances mobility,but with diminishing marginal effectiveness.From 0%to 40%ice content,run-out distance increases by 41%-86%,whereas the additional increase from 40%to 60%contributes only 12%-23%.Particle-size ratio strongly governs segregation intensity.Fine-gravel groups reach segregation indices ofα=0.92-0.98,indicating nearly complete upward migration of ice,whereas medium-gravel and coarse-gravel groups exhibit much weaker segregation,stabilizing atα=0.68-0.74 and 0.60-0.69.Savage number analyses reveal marked flow-regime transitions.At 0%ice content,Savage numbers reach 1.0-1.5,indicating a collisional regime.Increasing ice content suppresses collisionality,with Savage numbers decreasing to 0.03-0.07 at 60%ice content,consistent with dense-regime flow.DEM energy analyses confirm this regime shift:for finegravel mixtures,collision energy decreases by 14%,while sliding-friction energy increases by 33%as ice content increases from 0%to 60%,reflecting enhanced overburden effects imposed by upward-segregated ice layers.Medium and coarse mixtures exhibit weaker or opposite energy-shift patterns,demonstrating strong size dependence.Mechanistically,large particle-size contrasts promote strong segregation and form dense basal rock layers that increase basal friction and reduce mobility.When particle sizes are similar or ice content is high,segregation remains limited,allowing ice to mix into the basal layer,thereby reducing basal friction and enhancing mobility.This research quantitatively demonstrates how composition controls particle spatial distribution,flow regime,and energy dissipation,offering new mechanistic insights into the propagation and deposition behaviors of rock-ice avalanches and improving hazard assessment in vulnerable high-mountain regions.展开更多
Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated thr...Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated three typical two-dimensional negative Poisson’s ratio metamaterial structures(Concave honeycomb,Anti-chiral,and Anti-chiral concave honeycomb hybrid structures)through both experimental tests and numerical analysis.The test specimens were fabricated using selective laser melting(SLM)additive manufacturing technology,and the experimental test was conducted with the use of a DIC strain measurement system.The numerical studies were performed considering both static tensile loading and dynamic impact loading with different strain rates.The deformation behaviors,failure process,negative Poisson’s ratio effects,and energy absorption capacity of the three different metamaterial structures are systematically investigated,and the associated mechanical mechanisms are thoroughly revealed.Results and findings of this work could provide valuable guidance for the engineering design and application of negative Poisson’s ratio metamaterials and structures.展开更多
As the prevalence of obesity increases dramatically,obesity-associated cardiac dysfunction constitutes a considerable challenge to human health.This study aimed to identify more useful lipid/inflammatory markers to pr...As the prevalence of obesity increases dramatically,obesity-associated cardiac dysfunction constitutes a considerable challenge to human health.This study aimed to identify more useful lipid/inflammatory markers to predict the risk of obesity-associated cardiac dysfunction.By retrospectively analyzing the clinical characteristics of 5648 cardiac disease patients,we found that both the plasma level of high-density lipoprotein cholesterol(HDLC)and the blood monocyte count were significantly associated with impairment of the left ventricular ejection fraction(LVEF).Univariate and multivariate regression analyses revealed that the monocyte to HDL-C ratio(MHR)was a more powerful predictor of the risk of LVEF decline than either HDL-C or monocyte alone.Mediation analysis further revealed a mediating effect of a high MHR on the decline in obesity-associated cardiac systolic function.Collectively,our results demonstrate a superior role of MHR in predicting the risk of an obesityassociated decline in cardiac systolic function among routine metabolic/inflammatory markers.展开更多
In modern construction,Lightweight Aggregate Concrete(LWAC)has been recognized as a vital material of concern because of its unique properties,such as reduced density and improved thermal insulation.Despite the extens...In modern construction,Lightweight Aggregate Concrete(LWAC)has been recognized as a vital material of concern because of its unique properties,such as reduced density and improved thermal insulation.Despite the extensive knowledge regarding its macroscopic properties,there is a wide knowledge gap in understanding the influence of microscale parameters like aggregate porosity and volume ratio on the mechanical response of LWAC.This study aims to bridge this knowledge gap,spurred by the need to enhance the predictability and applicability of LWAC in various construction environments.With the help of advanced numerical methods,including the finite element method and a random circular aggregate model,this study critically evaluates the role played by these microscale factors.We found that an increase in the aggregate porosity from 23.5%to 48.5%leads to a drastic change of weakness from the bonding interface to the aggregate,reducing compressive strength by up to 24.2%and tensile strength by 27.8%.Similarly,the increase in the volume ratio of lightweight aggregate from 25%to 40%leads to a reduction in compressive strength by 13.0%and tensile strength by 9.23%.These results highlight the imperative role of microscale properties on the mechanical properties of LWAC.By supplying precise quantitative details on the effect of porosity and aggregate volume ratio,this research makes significant contributions to construction materials science by providing useful recommendations for the creation and optimization of LWAC with improved performance and sustainability in construction.展开更多
This study presents a framework involving statistical modeling and machine learning to accurately predict and optimize the mechanical and damping properties of hybrid granite-epoxy(G-E)composites reinforced with cast ...This study presents a framework involving statistical modeling and machine learning to accurately predict and optimize the mechanical and damping properties of hybrid granite-epoxy(G-E)composites reinforced with cast iron(CI)filler particles.Hybrid G-E composite with added cast iron(CI)filler particles enhances stiffness,strength,and vibration damping,offering enhanced performance for vibration-sensitive engineering applications.Unlike conventional approaches,this work simultaneously employs Artificial Neural Networks(ANN)for highaccuracy property prediction and Response Surface Methodology(RSM)for in-depth analysis of factor interactions and optimization.A total of 24 experimental test data sets of varying input factors(granite weight%,epoxy weight%,and CI filler weight%)were utilized to train and test the prediction models using an ANN approach and further analyze the interaction effects using RSM.Mechanical properties,including tensile,compressive,and flexural strength,elastic modulus,density and damping properties measured under various testing conditions,were set as output parameters for prediction.This study analyzed and optimized the performance of the ANN model using Bayesian Regularization and Levenberg-Marquardt algorithms to identify the best performing number of neurons in the hidden layer for achieving the highest prediction accuracy.The proposed ANN framework achieved an exceptional average determination coefficient(R2)exceeding 99%,with Bayesian Regularization demonstrating remarkable stability in the 22-neuron range and minimal variation across all properties.RSM and ANN form a powerful framework for predicting and optimizing hybrid G-E composite properties,enabling efficient design for vibration-critical applications with reduced experimental effort and performance optimization.展开更多
This study employed tri-component continuous monitoring data from 10 measurement points on both sides of a base isolation layer in the basement of a large-span high-rise building in Beijing,as well as from a free-fiel...This study employed tri-component continuous monitoring data from 10 measurement points on both sides of a base isolation layer in the basement of a large-span high-rise building in Beijing,as well as from a free-field station and roof frame,during a Mw 5.5 magnitude earthquake in Pingyuan,Shandong,in 2023.The H/V spectral ratio method was used to evaluate the structural dynamic response characteristics of the building and analyze the regulatory effect of the base-isolation layer on seismic waves.The results indicate that during the earthquake,the peak frequency of the free-field and the measurement points below the base-isolation layer was stable at 0.17 Hz,whereas the main frequency of the measurement points above the base-isolation layer increased to 0.75–1.18 Hz,which is 4–6 times greater than that of the points below.The amplitude was suppressed by more than 70%,confirming that the base isolation layer effectively isolated the low-frequency energy from the ground and increased the response frequency of the building.When the building was excited by an earthquake,a three-tier frequency gradient was formed throughout the building:“base-isolation layer(0.17 Hz)-main body(1.18 Hz)-roof frame(3.83 Hz)”,which can effectively avoid resonance of the entire building.In addition,the composite base-isolation device changed the dynamic characteristics of the structure.The resonance period was extended from 0.74 s(theoretical value without base isolation)to 5.9 s(calculated value),and the resonance frequency was reduced from 1.35 to 0.17 Hz.This finding indicates that the base-isolation layer can enhance seismic performance by increasing flexibility and damping.展开更多
Background:Panacis Quinquefolii Radix(PQR)is known for its ability to nourish“Qi”(it serves as the driving force for the functional activities of the body’s organs and meridians,promoting and regulating various phy...Background:Panacis Quinquefolii Radix(PQR)is known for its ability to nourish“Qi”(it serves as the driving force for the functional activities of the body’s organs and meridians,promoting and regulating various physiological functions)and“Yin”(it represents the material foundation of the human body.It plays a role in nourishing,moistening,and cooling the body).Notoginseng Radix et Rhizoma(NRR)is recognized for its properties of resolving blood stasis(it refers to a pathological condition characterized by impaired or stagnant blood circulation within the body).Changes in the compatibility ratio of these herbs often lead to variations in their chemical composition and efficacy.However,the specific alterations in chemical composition and efficacy resulting from compatibility adjustments remain unclear.We aimed to compare the material basis and their effects of different compatibility ratios of PQR and NRR on“Qi”deficiency and blood stasis syndrome(QBS).Methods:This study employed UPLC-Q/TOF-MS to identify effective compounds in the compatibility of PQR and NRR and utilized UPLC-TQ-MS/MS to analyze the dissolution of 16 saponins in PQR and NRR at 9 different ratios.A rat model of QBS was established,and the efficacy of PQR and NRR in treating this syndrome was assessed using hemorheology and coagulation analyses.Results:The study results show that PQR and NRR exhibit significant efficacy,effectively reducing blood viscosity induced by platelet aggregation and lowering inflammatory markers such as IL-6,IL-10,TXB2 and ET associated with vascular injury.Moreover,this combination regulates ATP and ADP levels,enhances energy metabolism,and promotes overall health.A total of 104 compounds in the compatibility of PQR and NRR were identified.The ratios of 1:2 and 1:3 showed the highest total saponin content,but the ratio of 1:1 demonstrated a superior pharmacological effect for the treatment of QBS.Conclusion:In summary,the compatibility of PQR and NRR not only shows the complex interactions between traditional Chinese medicinal materials,but also provides a new idea and method for the treatment of QBS.展开更多
To resolve severe slag penetration and erosion in Al_(2)O_(3)-SiC-C refractories during high scrap ratio iron ladle operation,a novel strategy utilizing exogenous MgAl_(2)O_(4) spinel as a sacrificial FeO_(x) scavenge...To resolve severe slag penetration and erosion in Al_(2)O_(3)-SiC-C refractories during high scrap ratio iron ladle operation,a novel strategy utilizing exogenous MgAl_(2)O_(4) spinel as a sacrificial FeO_(x) scavenger was proposed.Al_(2)O_(3)-SiC-C refractories produced with plate-like corundum,silicon carbide,and flake graphite incorporating MgAl_(2)O_(4) additives were cured at 1400℃ in the condition of carbon embedding.The impacts of additives on phase composition,microscopic morphology,and performance of materials were studied.The results indicated that Al_(2)O_(3)-SiC-C refractories with the addition of 2 wt.%MgAl_(2)O_(4) exhibited a smaller oxidation area after oxidation tests compared to samples without MgAl_(2)O_(4),resulting in 28%improvement in oxidation resistance compared to blank samples.In the erosion test,the results informed that adding 4 wt.%MgAl_(2)O_(4) induced significant interfacial slag modification:MgAl_(2)O_(4) dynamically dissolved FeO_(x) to form protective Mg(Fe,Al)_(2)O_(4) solid solution on the slag-refractory interface.This sacrificial dissolution effectively immobilized FeO_(x),elevated local slag viscosity,and fundamentally inhibited slag penetration and matrix dissolution.The erosion index decreased from 50%in the blank group to 27.4%.展开更多
Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a...Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a dominant tree species along the Tarim River watershed, plays an irreplaceable role in the sustainable development of regional ecology, economy and society. However, as the result of climate changes and human activities, the natural riparian ecosystems within the whole river basin were degraded enormously, particularly in the lower reaches of the river where about 320 km of the riparian forests were either highly degraded or dead. In this study, we presented one of the main criteria for the assessment of vitality of P. euphrafica forests by estimating the defoliation level, and analyzed forest structure and determined the height-diameter （height means the height of a tree and diameter means the diameter at breast height （DBH） of a tree） relationship of trees in different vitality classes （i.e. healthy, good, medium, senesced, dying, dead and fallen）. Trees classified as healthy and good ac- counted for approximately 40% of all sample trees, while slightly and highly degraded trees took up nearly 60% of total sample trees. The values of TH （tree height） and DBH ranged from 0-19 m and 0-125 cm, respectively. Trees more than 15 m in TH and 60 cm in DBH appeared sporadically. Trees in different vitality classes had different distribution patterns. Healthy trees were mainly composed more of relatively younger trees than of degraded tress. The height-diameter relationships differed greatly among tress in different vitality classes, with the coefficients ranging from 0.1653 to 0.6942. Correlation coefficients of TH and DBH in healthy and good trees were higher than those in trees of other vitality classes. The correlation between TH and DBH decreased with the decline of tree vitality. Our results suggested that it might be able to differentiate degraded P. euphratica trees from healthy trees by determining the height-diameter correlation coefficient, and the coefficient would be a new parameter for detecting degradation and assessing sustainable management of floodplain forests in arid regions. In addition, tree vitality should be taken into account to make an accurate height-diameter model for tree height prediction.展开更多
Background： Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest ...Background： Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height （dbh） can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter （h-d） models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods： We develop unconstrained generalized additive models （GAM） and shape constrained generalized additive models （SCAM） for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results： Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand, The definition of constraints leads only to marginal or minor decline in the model statistics like AIC An observed structured spatial trend in tree height is modelled via 2-dimensional surface fitting. Conclusions： We demonstrate that the SCAM approach allows optimal regression modelling flexibility similar to the standard GAM but with the additional possibility of defining specific constraints for the model effects. The longitudinal character of the model allows for tree height imputation for the current status of forests but also for future tree height prediction.展开更多
Modelling tree height-diameter relationships in complex tropical rain forest ecosystems remains a challenge because of characteristics of multi-species, multi-layers, and indeterminate age composition. Effective model...Modelling tree height-diameter relationships in complex tropical rain forest ecosystems remains a challenge because of characteristics of multi-species, multi-layers, and indeterminate age composition. Effective modelling of such complex systems required innovative techniques to improve prediction of tree heights for use for aboveground biomass estimations. Therefore, in this study, deep learning algorithm (DLA) models based on artificial intelligence were trained for predicting tree heights in a tropical rain forest of Nigeria. The data consisted of 1736 individual trees representing 116 species, and measured from 52 0.25 ha sample plots. A K-means clustering was used to classify the species into three groups based on height-diameter ratios. The DLA models were trained for each species-group in which diameter at beast height, quadratic mean diameter and number of trees per ha were used as input variables. Predictions by the DLA models were compared with those developed by nonlinear least squares (NLS) and nonlinear mixed-effects (NLME) using different evaluation statistics and equivalence test. In addition, the predicted heights by the models were used to estimate aboveground biomass. The results showed that the DLA models with 100 neurons in 6 hidden layers, 100 neurons in 9 hidden layers and 100 neurons in 7 hidden layers for groups 1, 2, and 3, respectively, outperformed the NLS and NLME models. The root mean square error for the DLA models ranged from 1.939 to 3.887 m. The results also showed that using height predicted by the DLA models for aboveground biomass estimation brought about more than 30% reduction in error relative to NLS and NLME. Consequently, minimal errors were created in aboveground biomass estimation compared to those of the classical methods.展开更多
Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pe...Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.展开更多
The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflectio...The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflection points of H-D models.The goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional dataset.The six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPZ)models.The models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial distribution.The distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and GPZ.GPZ produced some of the largest inflection points.HOS and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree species.Evergreen species or decreasing shade tolerance resulted in larger inflection points.The trends in the estimated inflection points of HOS and VBR were entirely opposite across the landscape.Furthermore,HOS could produce concave H-D curves for portions of the landscape.Based on the studied behaviors,the choice between two-parameter models may not matter.We recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on one.Believing sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with one.Our study highlights the need to integrate analysis of inflection points into modeling H-D relationships.展开更多
BACKGROUND The diagnosis of gastric carcinoma(GC)is essential for improving clinical outcomes.However,the biomarkers currently used for GC screening are not ideal.AIM To explore the diagnostic implications of the neut...BACKGROUND The diagnosis of gastric carcinoma(GC)is essential for improving clinical outcomes.However,the biomarkers currently used for GC screening are not ideal.AIM To explore the diagnostic implications of the neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),and systemic immune-inflammatory index(SII)for GC.METHODS The baseline data of 133 patients with GC and 134 patients with precancerous gastric conditions admitted between January 2022 and December 2023 were retrospectively analyzed.The information on peripheral blood platelet,neutrophil,and lymphocyte counts in each patient was collected,and the NLR,PLR,and SII levels of both groups were calculated.Additionally,multivariate logistic regression analysis was conducted,and the diagnostic implications of NLR,PLR,and SII in differentiating patients with precancerous gastric conditions,compared with those with GC,were analyzed through receiver operating characteristic(ROC)curves.RESULTS The data indicated that NLR,PLR,and SII had abnormally increased levels in the patients with GC.Gender and body mass index were risk factors for the occurrence of GC.ROC data revealed that the areas under the curve of three patients with precancerous gastric conditions,who were differentiated from those with GC,were 0.824,0.787,and 0.842,respectively.CONCLUSION NLR,PLR,and SII are all abnormally expressed in GC and have diagnostic implications,especially when used as joint indicators,in distinguishing patients with precancerous gastric conditions from those with GC.展开更多
BACKGROUND The use of biomarkers,such as the neutrophil-to-lymphocyte ratio(NLR)and the neutrophil-to-platelet ratio(NPR),has shown promise in evaluating early outcomes after medical,interventional,and surgical treatm...BACKGROUND The use of biomarkers,such as the neutrophil-to-lymphocyte ratio(NLR)and the neutrophil-to-platelet ratio(NPR),has shown promise in evaluating early outcomes after medical,interventional,and surgical treatments.NLR has emer-ged as an indicator of systemic inflammation and physiological stress.NPR has emerged as a potential indicator of inflammation and thrombotic risk in the context of surgical and radiological procedures.AIM To analyze the correlation of NLR and NPR with the development of post-liver transplantation(LT)early complications after stratification for hepatocellular carcinoma diagnosis.METHODS Consecutive patients undergone LT between January 2019 and December 2023 were enrolled.Data regarding the concentration of hemoglobin and the differ-ential leukocyte count on postoperative days(POD)0,1,3,and 5 were collected.RESULTS The dataset included 161 consecutive patients undergone LT.Clavien-Dindo IV-V complications had a good correlation with NLR POD 1(P=0.05),NLR POD 3(P<0.001),NLR POD 7(P<0.001),NPR POD 3(P<0.001).In addition,the NPR ratio on POD 3 correlated with the onset of 30-day hemorrhage(P=0.009).Finally,30-day mortality had a significant association with the NLR POD 1(P=0.03)and with NLR POD 7(P=0.004),while NPR had a significant correlation with 30-day mortality in NPR POD 7(P=0.004).CONCLUSION The analysis of NLR and NPR are strictly correlated with Clavien-Dindo IV-V complications and 30-day post-LT death.展开更多
A high-speed train travelling from the open air into a narrow tunnel will cause the“sonic boom”at tunnel exit.When the maglev train’s speed reaches 600 km/h,the train-tunnel aerodynamic effect is intensified,so a n...A high-speed train travelling from the open air into a narrow tunnel will cause the“sonic boom”at tunnel exit.When the maglev train’s speed reaches 600 km/h,the train-tunnel aerodynamic effect is intensified,so a new mitigation method is urgently expected to be explored.This study proposed a novel asymptotic linear method(ALM)for micro pressure wave(MPW)mitigation to achieve a constant gradient of initial c ompression waves(ICWs),via a study with various open ratios on hoods.The properties of ICWs and MPWs under various open ratios of hoods were analyzed.The results show that as the open ratio increases,the MPW amplitude at the tunnel exit initially decreases before rising.At the open ratio of 2.28%,the slope of the ICW curve is linearly coincident with a supposed straight line in the ALM,which further reduces the MPW amplitude by 26.9%at 20 m and 20.0%at 50 m from the exit,as compared to the unvented hood.Therefore,the proposed method effectively mitigates MPW and quickly determines the upper limit of alleviation for the MPW amplitude at a fixed train-tunnel operation condition.All achievements provide a ne w potential measure for the adaptive design of tunnel hoods.展开更多
Objective Peritoneal carcinomatosis(PC)is a common pattern of recurrence in gastric cancer patients and is associated with a poor prognosis.This study aimed to evaluate the predictive value of the albumin-fibrinogen r...Objective Peritoneal carcinomatosis(PC)is a common pattern of recurrence in gastric cancer patients and is associated with a poor prognosis.This study aimed to evaluate the predictive value of the albumin-fibrinogen ratio(AFR)for PC in patients with gastric cancer and to develop two preoperative prediction models.Methods A total of 745 gastric cancer patients were included in this study.Preoperative AFR,along with other serum markers and clinical tumor characteristics,was assessed.Univariate and multivariate logistic regression analyses were performed to determine the odds ratios(ORs)and 95%confidence intervals(CIs)of the independent variables.Propensity score matching(PSM)was used to control for potential confounders,and one-way ANOVA was conducted to evaluate differences in distribution between groups.Two prediction models incorporating the independent predictive indicators were constructed and validated via receiver operating characteristic(ROC)curves.Results Poorly differentiated type(OR 2.679;P=0.001),nondiffuse morphological type(OR 2.123;P=0.040),BMI<23.550 kg/m^(2)(OR 4.635;P=0.001),AFR<11.275(OR 2.895;P=0.003)and CA199≥73.615 U/mL(OR 2.040;P=0.037)were identified as independent risk factors for PC in patients with gastric cancer.After PSM,the AFR remained the only inflammatory marker that was independently associated with PC(P=0.003).AFR demonstrated consistent robustness in predicting PC across multiple sample sets.Among all the independent risk factors,the AFR had the highest area under the curve(AUC)for ROC analysis(AUC 0.648;95%CI 0.580–0.715).Two combination models incorporating the AFR demonstrated enhanced predictive ability:Combination Model 1(AUC 0.759;95%CI 0.699–0.820)and Combination Model 2(AUC 0.801;95%CI 0.744–0.859).Conclusions The preoperative AFR serves as a useful indicator for predicting PC.Two reliable prediction models based on the AFR have been developed.展开更多
The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with B...The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with Bi/Si ratio in low-melting glass was investigated.In addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were revealed.The results show that a decrease in the Bi/Si ratio can cause a contraction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its coefficient of thermal expansion.During laser sealing,the copper ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the copper ions in the low-melting glass.The absorbance of the low-melting glass does not follow the expected correlation with the Bi/Si ratio,but shows a linear correlation with the content of divalent copper ions.The greater the concentration of divalent copper ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser sealing.The shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.展开更多
Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb...Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb,respectively.The effects of microstructure,texture,crack propagation behavior and second phase precipitation behavior on hole expansion ratio were investigated.The precipitation behavior of TiC and(Ti,Nb)C in austenite and ferrite in three groups of steel samples was calculated theoretically.The results showed that the hole expansion ratios of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 51.73%,51.17%and 66.24%following simulated coiling at 600℃,respectively.The microstructure was mainly polygonal ferrite with a small amount of pearlite.The grain refinement of 0.097Ti–0.059Nb test steel and the low texture ratio of{110}//ND improved the hole expansion ratio.The low overall hole expansion ratio was due to the microstructure inhomogeneity.The microstructure uniformity was improved by the quenching and tempering treatment,and the hole expansion ratio of the three test steels was greatly increased.The fastest precipitation temperatures in the austenitic region of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 880,860 and 830℃,while those in the ferrite region were 680,675 and 675℃,respectively.The addition of Nb element increased the volume free energy,so that the critical core size of the nucleation on the dislocation line increased,resulting in the decrease in the fastest precipitation temperature.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.51927808,52174098 and 52374151).
文摘Geological exploration cores obtained from shale gas wells several kilometers deep often show different height-diameter ratios(H/D)because of complex geological conditions(core disking or developed fractures),which makes further standard specimen preparation for mechanical evaluation of reservoirs difficult.In multi-cluster hydraulic fracturing,shale reservoirs between planes of hydraulic fractures with different lengths could be simplified to have different H/D ratios.Discovering the effect of H/D on the mechanical characteristics of shale specimens with different bedding orientations will support mechanical evaluation tests of reservoirs based on disked geological cores and help to optimize multicluster fracturing programs.In this study,we performed uniaxial compression tests and acoustic emission(AE)monitoring on cylindrical Longmaxi shale specimens under five bedding orientations and four H/D ratios.The experimental results showed that both the H/D-dependent mechanical properties and AE parameters demonstrated significant anisotropy.Increasing H/D did not change the uniaxial compressive strength(UCS)evolution versus bedding orientation,demonstrating a V-shaped relationship,but enhanced the curve shape.The stress level of crack damage for the specimens significantly increased with increasing H/D,excluding the specimens with a bedding orientation of 0°.With increasing H/D,the cumulative AE counts of the specimens with each bedding orientation tended to exhibit a stepped jump against the loading time.The proportion of low-average-frequency AE signals(below 100 kHz)in specimens with bedding orientations of 45°and 60°increased to over 70%by increasing H/D,but it only increased to 40%in specimens with bedding orientations of 0°,30°,and 90°.Finally,an empirical model that can reveal the effect of H/D on anisotropic UCS of shale reservoir was proposed,the anisotropic proportion of tensile and shear failure cracks in specimens under four H/D ratios was classified based on the AE data,and the effect of H/D on the anisotropic crack growth of specimens was discussed.
基金funded by the Natural Science Foundation of China(Grants No 42277127)。
文摘Rock-ice avalanches in cold high-mountain regions pose severe hazards due to their high mobility,yet the quantitative controls of particle-size ratio and ice content remain insufficiently constrained.This study investigates their coupled effects using inclinedflume experiments and Discrete Element Method(DEM)simulations,covering three gravel sizes(2-5 mm,5-7 mm,7-10 mm)and four ice-content levels(0%,20%,40%,60%).Run-out distance,velocity,energy components,flow regime(Savage number),and segregation indexαwere quantified.Increasing ice content significantly enhances mobility,but with diminishing marginal effectiveness.From 0%to 40%ice content,run-out distance increases by 41%-86%,whereas the additional increase from 40%to 60%contributes only 12%-23%.Particle-size ratio strongly governs segregation intensity.Fine-gravel groups reach segregation indices ofα=0.92-0.98,indicating nearly complete upward migration of ice,whereas medium-gravel and coarse-gravel groups exhibit much weaker segregation,stabilizing atα=0.68-0.74 and 0.60-0.69.Savage number analyses reveal marked flow-regime transitions.At 0%ice content,Savage numbers reach 1.0-1.5,indicating a collisional regime.Increasing ice content suppresses collisionality,with Savage numbers decreasing to 0.03-0.07 at 60%ice content,consistent with dense-regime flow.DEM energy analyses confirm this regime shift:for finegravel mixtures,collision energy decreases by 14%,while sliding-friction energy increases by 33%as ice content increases from 0%to 60%,reflecting enhanced overburden effects imposed by upward-segregated ice layers.Medium and coarse mixtures exhibit weaker or opposite energy-shift patterns,demonstrating strong size dependence.Mechanistically,large particle-size contrasts promote strong segregation and form dense basal rock layers that increase basal friction and reduce mobility.When particle sizes are similar or ice content is high,segregation remains limited,allowing ice to mix into the basal layer,thereby reducing basal friction and enhancing mobility.This research quantitatively demonstrates how composition controls particle spatial distribution,flow regime,and energy dissipation,offering new mechanistic insights into the propagation and deposition behaviors of rock-ice avalanches and improving hazard assessment in vulnerable high-mountain regions.
基金supported by the National Natural Science Foundation of China(No.12472136)Innovation Fund of Marine Defense Technology Innovation Center(No.25GFC-JJ16-3608).
文摘Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated three typical two-dimensional negative Poisson’s ratio metamaterial structures(Concave honeycomb,Anti-chiral,and Anti-chiral concave honeycomb hybrid structures)through both experimental tests and numerical analysis.The test specimens were fabricated using selective laser melting(SLM)additive manufacturing technology,and the experimental test was conducted with the use of a DIC strain measurement system.The numerical studies were performed considering both static tensile loading and dynamic impact loading with different strain rates.The deformation behaviors,failure process,negative Poisson’s ratio effects,and energy absorption capacity of the three different metamaterial structures are systematically investigated,and the associated mechanical mechanisms are thoroughly revealed.Results and findings of this work could provide valuable guidance for the engineering design and application of negative Poisson’s ratio metamaterials and structures.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.82430018 to Q.C.,82270361 and 82570402 to H.Z.)the Nanjing Medical University Undergraduate Innovation and Entrepreneurship Training Program Fund(Grant No.202410312138Y to C.Z.)the Basic Sciences of Jiangsu Higher Education Institutions(Grant No.22KJA310002 to H.Z.)。
文摘As the prevalence of obesity increases dramatically,obesity-associated cardiac dysfunction constitutes a considerable challenge to human health.This study aimed to identify more useful lipid/inflammatory markers to predict the risk of obesity-associated cardiac dysfunction.By retrospectively analyzing the clinical characteristics of 5648 cardiac disease patients,we found that both the plasma level of high-density lipoprotein cholesterol(HDLC)and the blood monocyte count were significantly associated with impairment of the left ventricular ejection fraction(LVEF).Univariate and multivariate regression analyses revealed that the monocyte to HDL-C ratio(MHR)was a more powerful predictor of the risk of LVEF decline than either HDL-C or monocyte alone.Mediation analysis further revealed a mediating effect of a high MHR on the decline in obesity-associated cardiac systolic function.Collectively,our results demonstrate a superior role of MHR in predicting the risk of an obesityassociated decline in cardiac systolic function among routine metabolic/inflammatory markers.
基金supported by National Science Foundation of China(10972015,11172015)the Beijing Natural Science Foundation(8162008).
文摘In modern construction,Lightweight Aggregate Concrete(LWAC)has been recognized as a vital material of concern because of its unique properties,such as reduced density and improved thermal insulation.Despite the extensive knowledge regarding its macroscopic properties,there is a wide knowledge gap in understanding the influence of microscale parameters like aggregate porosity and volume ratio on the mechanical response of LWAC.This study aims to bridge this knowledge gap,spurred by the need to enhance the predictability and applicability of LWAC in various construction environments.With the help of advanced numerical methods,including the finite element method and a random circular aggregate model,this study critically evaluates the role played by these microscale factors.We found that an increase in the aggregate porosity from 23.5%to 48.5%leads to a drastic change of weakness from the bonding interface to the aggregate,reducing compressive strength by up to 24.2%and tensile strength by 27.8%.Similarly,the increase in the volume ratio of lightweight aggregate from 25%to 40%leads to a reduction in compressive strength by 13.0%and tensile strength by 9.23%.These results highlight the imperative role of microscale properties on the mechanical properties of LWAC.By supplying precise quantitative details on the effect of porosity and aggregate volume ratio,this research makes significant contributions to construction materials science by providing useful recommendations for the creation and optimization of LWAC with improved performance and sustainability in construction.
文摘This study presents a framework involving statistical modeling and machine learning to accurately predict and optimize the mechanical and damping properties of hybrid granite-epoxy(G-E)composites reinforced with cast iron(CI)filler particles.Hybrid G-E composite with added cast iron(CI)filler particles enhances stiffness,strength,and vibration damping,offering enhanced performance for vibration-sensitive engineering applications.Unlike conventional approaches,this work simultaneously employs Artificial Neural Networks(ANN)for highaccuracy property prediction and Response Surface Methodology(RSM)for in-depth analysis of factor interactions and optimization.A total of 24 experimental test data sets of varying input factors(granite weight%,epoxy weight%,and CI filler weight%)were utilized to train and test the prediction models using an ANN approach and further analyze the interaction effects using RSM.Mechanical properties,including tensile,compressive,and flexural strength,elastic modulus,density and damping properties measured under various testing conditions,were set as output parameters for prediction.This study analyzed and optimized the performance of the ANN model using Bayesian Regularization and Levenberg-Marquardt algorithms to identify the best performing number of neurons in the hidden layer for achieving the highest prediction accuracy.The proposed ANN framework achieved an exceptional average determination coefficient(R2)exceeding 99%,with Bayesian Regularization demonstrating remarkable stability in the 22-neuron range and minimal variation across all properties.RSM and ANN form a powerful framework for predicting and optimizing hybrid G-E composite properties,enabling efficient design for vibration-critical applications with reduced experimental effort and performance optimization.
基金supported by the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(Grant No.2025ZD005100)by Beijing Geolight Technology Co.,Ltd.under the project“The Impact of Strong Ground Motion on Buildings”(YF-202520).
文摘This study employed tri-component continuous monitoring data from 10 measurement points on both sides of a base isolation layer in the basement of a large-span high-rise building in Beijing,as well as from a free-field station and roof frame,during a Mw 5.5 magnitude earthquake in Pingyuan,Shandong,in 2023.The H/V spectral ratio method was used to evaluate the structural dynamic response characteristics of the building and analyze the regulatory effect of the base-isolation layer on seismic waves.The results indicate that during the earthquake,the peak frequency of the free-field and the measurement points below the base-isolation layer was stable at 0.17 Hz,whereas the main frequency of the measurement points above the base-isolation layer increased to 0.75–1.18 Hz,which is 4–6 times greater than that of the points below.The amplitude was suppressed by more than 70%,confirming that the base isolation layer effectively isolated the low-frequency energy from the ground and increased the response frequency of the building.When the building was excited by an earthquake,a three-tier frequency gradient was formed throughout the building:“base-isolation layer(0.17 Hz)-main body(1.18 Hz)-roof frame(3.83 Hz)”,which can effectively avoid resonance of the entire building.In addition,the composite base-isolation device changed the dynamic characteristics of the structure.The resonance period was extended from 0.74 s(theoretical value without base isolation)to 5.9 s(calculated value),and the resonance frequency was reduced from 1.35 to 0.17 Hz.This finding indicates that the base-isolation layer can enhance seismic performance by increasing flexibility and damping.
基金funded by the Entrusted service project of Shaanxi Administration of Traditional Chinese Medicine(ZYJXG-L23001)2023 Sanqin Talent Special Support Program Innovation and Entrepreneurship Team Project,and Sci-Tech Innovation Talent System Construction Program of Shaanxi University of Chinese Medicine(2023).
文摘Background:Panacis Quinquefolii Radix(PQR)is known for its ability to nourish“Qi”(it serves as the driving force for the functional activities of the body’s organs and meridians,promoting and regulating various physiological functions)and“Yin”(it represents the material foundation of the human body.It plays a role in nourishing,moistening,and cooling the body).Notoginseng Radix et Rhizoma(NRR)is recognized for its properties of resolving blood stasis(it refers to a pathological condition characterized by impaired or stagnant blood circulation within the body).Changes in the compatibility ratio of these herbs often lead to variations in their chemical composition and efficacy.However,the specific alterations in chemical composition and efficacy resulting from compatibility adjustments remain unclear.We aimed to compare the material basis and their effects of different compatibility ratios of PQR and NRR on“Qi”deficiency and blood stasis syndrome(QBS).Methods:This study employed UPLC-Q/TOF-MS to identify effective compounds in the compatibility of PQR and NRR and utilized UPLC-TQ-MS/MS to analyze the dissolution of 16 saponins in PQR and NRR at 9 different ratios.A rat model of QBS was established,and the efficacy of PQR and NRR in treating this syndrome was assessed using hemorheology and coagulation analyses.Results:The study results show that PQR and NRR exhibit significant efficacy,effectively reducing blood viscosity induced by platelet aggregation and lowering inflammatory markers such as IL-6,IL-10,TXB2 and ET associated with vascular injury.Moreover,this combination regulates ATP and ADP levels,enhances energy metabolism,and promotes overall health.A total of 104 compounds in the compatibility of PQR and NRR were identified.The ratios of 1:2 and 1:3 showed the highest total saponin content,but the ratio of 1:1 demonstrated a superior pharmacological effect for the treatment of QBS.Conclusion:In summary,the compatibility of PQR and NRR not only shows the complex interactions between traditional Chinese medicinal materials,but also provides a new idea and method for the treatment of QBS.
基金support from the project supported by the National Natural Science Foundation of China(Grant No.52402034)the Science and Technology Innovation Team Foundation of Hubei Province(Grant No.T2023001)+1 种基金the Natural Science Foundation of Hubei Province(Grant No.2023BAB106)the Natural Science Foundation of Wuhan(Grant No.2024040701010051).
文摘To resolve severe slag penetration and erosion in Al_(2)O_(3)-SiC-C refractories during high scrap ratio iron ladle operation,a novel strategy utilizing exogenous MgAl_(2)O_(4) spinel as a sacrificial FeO_(x) scavenger was proposed.Al_(2)O_(3)-SiC-C refractories produced with plate-like corundum,silicon carbide,and flake graphite incorporating MgAl_(2)O_(4) additives were cured at 1400℃ in the condition of carbon embedding.The impacts of additives on phase composition,microscopic morphology,and performance of materials were studied.The results indicated that Al_(2)O_(3)-SiC-C refractories with the addition of 2 wt.%MgAl_(2)O_(4) exhibited a smaller oxidation area after oxidation tests compared to samples without MgAl_(2)O_(4),resulting in 28%improvement in oxidation resistance compared to blank samples.In the erosion test,the results informed that adding 4 wt.%MgAl_(2)O_(4) induced significant interfacial slag modification:MgAl_(2)O_(4) dynamically dissolved FeO_(x) to form protective Mg(Fe,Al)_(2)O_(4) solid solution on the slag-refractory interface.This sacrificial dissolution effectively immobilized FeO_(x),elevated local slag viscosity,and fundamentally inhibited slag penetration and matrix dissolution.The erosion index decreased from 50%in the blank group to 27.4%.
基金supported by International Science & Technology Cooperation Program of China (2010DFA92720-12)the National Natural Science Foundation of China (31360200)+1 种基金the German Volkswagen Foundation Eco CAR Project (Az88497)the German Federal Ministry of Education and Research (BMBF) within the framework of the Su Ma Ri O Project (01LL0918D)
文摘Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a dominant tree species along the Tarim River watershed, plays an irreplaceable role in the sustainable development of regional ecology, economy and society. However, as the result of climate changes and human activities, the natural riparian ecosystems within the whole river basin were degraded enormously, particularly in the lower reaches of the river where about 320 km of the riparian forests were either highly degraded or dead. In this study, we presented one of the main criteria for the assessment of vitality of P. euphrafica forests by estimating the defoliation level, and analyzed forest structure and determined the height-diameter （height means the height of a tree and diameter means the diameter at breast height （DBH） of a tree） relationship of trees in different vitality classes （i.e. healthy, good, medium, senesced, dying, dead and fallen）. Trees classified as healthy and good ac- counted for approximately 40% of all sample trees, while slightly and highly degraded trees took up nearly 60% of total sample trees. The values of TH （tree height） and DBH ranged from 0-19 m and 0-125 cm, respectively. Trees more than 15 m in TH and 60 cm in DBH appeared sporadically. Trees in different vitality classes had different distribution patterns. Healthy trees were mainly composed more of relatively younger trees than of degraded tress. The height-diameter relationships differed greatly among tress in different vitality classes, with the coefficients ranging from 0.1653 to 0.6942. Correlation coefficients of TH and DBH in healthy and good trees were higher than those in trees of other vitality classes. The correlation between TH and DBH decreased with the decline of tree vitality. Our results suggested that it might be able to differentiate degraded P. euphratica trees from healthy trees by determining the height-diameter correlation coefficient, and the coefficient would be a new parameter for detecting degradation and assessing sustainable management of floodplain forests in arid regions. In addition, tree vitality should be taken into account to make an accurate height-diameter model for tree height prediction.
文摘Background： Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height （dbh） can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter （h-d） models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods： We develop unconstrained generalized additive models （GAM） and shape constrained generalized additive models （SCAM） for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results： Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand, The definition of constraints leads only to marginal or minor decline in the model statistics like AIC An observed structured spatial trend in tree height is modelled via 2-dimensional surface fitting. Conclusions： We demonstrate that the SCAM approach allows optimal regression modelling flexibility similar to the standard GAM but with the additional possibility of defining specific constraints for the model effects. The longitudinal character of the model allows for tree height imputation for the current status of forests but also for future tree height prediction.
文摘Modelling tree height-diameter relationships in complex tropical rain forest ecosystems remains a challenge because of characteristics of multi-species, multi-layers, and indeterminate age composition. Effective modelling of such complex systems required innovative techniques to improve prediction of tree heights for use for aboveground biomass estimations. Therefore, in this study, deep learning algorithm (DLA) models based on artificial intelligence were trained for predicting tree heights in a tropical rain forest of Nigeria. The data consisted of 1736 individual trees representing 116 species, and measured from 52 0.25 ha sample plots. A K-means clustering was used to classify the species into three groups based on height-diameter ratios. The DLA models were trained for each species-group in which diameter at beast height, quadratic mean diameter and number of trees per ha were used as input variables. Predictions by the DLA models were compared with those developed by nonlinear least squares (NLS) and nonlinear mixed-effects (NLME) using different evaluation statistics and equivalence test. In addition, the predicted heights by the models were used to estimate aboveground biomass. The results showed that the DLA models with 100 neurons in 6 hidden layers, 100 neurons in 9 hidden layers and 100 neurons in 7 hidden layers for groups 1, 2, and 3, respectively, outperformed the NLS and NLME models. The root mean square error for the DLA models ranged from 1.939 to 3.887 m. The results also showed that using height predicted by the DLA models for aboveground biomass estimation brought about more than 30% reduction in error relative to NLS and NLME. Consequently, minimal errors were created in aboveground biomass estimation compared to those of the classical methods.
基金supported by the Norwegian Institute of Bioeconomy Research(NIBIO)
文摘Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.
文摘The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflection points of H-D models.The goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional dataset.The six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPZ)models.The models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial distribution.The distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and GPZ.GPZ produced some of the largest inflection points.HOS and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree species.Evergreen species or decreasing shade tolerance resulted in larger inflection points.The trends in the estimated inflection points of HOS and VBR were entirely opposite across the landscape.Furthermore,HOS could produce concave H-D curves for portions of the landscape.Based on the studied behaviors,the choice between two-parameter models may not matter.We recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on one.Believing sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with one.Our study highlights the need to integrate analysis of inflection points into modeling H-D relationships.
文摘BACKGROUND The diagnosis of gastric carcinoma(GC)is essential for improving clinical outcomes.However,the biomarkers currently used for GC screening are not ideal.AIM To explore the diagnostic implications of the neutrophil-to-lymphocyte ratio(NLR),platelet-to-lymphocyte ratio(PLR),and systemic immune-inflammatory index(SII)for GC.METHODS The baseline data of 133 patients with GC and 134 patients with precancerous gastric conditions admitted between January 2022 and December 2023 were retrospectively analyzed.The information on peripheral blood platelet,neutrophil,and lymphocyte counts in each patient was collected,and the NLR,PLR,and SII levels of both groups were calculated.Additionally,multivariate logistic regression analysis was conducted,and the diagnostic implications of NLR,PLR,and SII in differentiating patients with precancerous gastric conditions,compared with those with GC,were analyzed through receiver operating characteristic(ROC)curves.RESULTS The data indicated that NLR,PLR,and SII had abnormally increased levels in the patients with GC.Gender and body mass index were risk factors for the occurrence of GC.ROC data revealed that the areas under the curve of three patients with precancerous gastric conditions,who were differentiated from those with GC,were 0.824,0.787,and 0.842,respectively.CONCLUSION NLR,PLR,and SII are all abnormally expressed in GC and have diagnostic implications,especially when used as joint indicators,in distinguishing patients with precancerous gastric conditions from those with GC.
文摘BACKGROUND The use of biomarkers,such as the neutrophil-to-lymphocyte ratio(NLR)and the neutrophil-to-platelet ratio(NPR),has shown promise in evaluating early outcomes after medical,interventional,and surgical treatments.NLR has emer-ged as an indicator of systemic inflammation and physiological stress.NPR has emerged as a potential indicator of inflammation and thrombotic risk in the context of surgical and radiological procedures.AIM To analyze the correlation of NLR and NPR with the development of post-liver transplantation(LT)early complications after stratification for hepatocellular carcinoma diagnosis.METHODS Consecutive patients undergone LT between January 2019 and December 2023 were enrolled.Data regarding the concentration of hemoglobin and the differ-ential leukocyte count on postoperative days(POD)0,1,3,and 5 were collected.RESULTS The dataset included 161 consecutive patients undergone LT.Clavien-Dindo IV-V complications had a good correlation with NLR POD 1(P=0.05),NLR POD 3(P<0.001),NLR POD 7(P<0.001),NPR POD 3(P<0.001).In addition,the NPR ratio on POD 3 correlated with the onset of 30-day hemorrhage(P=0.009).Finally,30-day mortality had a significant association with the NLR POD 1(P=0.03)and with NLR POD 7(P=0.004),while NPR had a significant correlation with 30-day mortality in NPR POD 7(P=0.004).CONCLUSION The analysis of NLR and NPR are strictly correlated with Clavien-Dindo IV-V complications and 30-day post-LT death.
基金Project(24A0006)supported by the Key Project of Scientific Research Fund of Hunan Provincial Department of Education,ChinaProject(2024JJ5430)supported by the Natural Science Foundation of Hunan Province,ChinaProjects(2024JK2045,2023RC3061)supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘A high-speed train travelling from the open air into a narrow tunnel will cause the“sonic boom”at tunnel exit.When the maglev train’s speed reaches 600 km/h,the train-tunnel aerodynamic effect is intensified,so a new mitigation method is urgently expected to be explored.This study proposed a novel asymptotic linear method(ALM)for micro pressure wave(MPW)mitigation to achieve a constant gradient of initial c ompression waves(ICWs),via a study with various open ratios on hoods.The properties of ICWs and MPWs under various open ratios of hoods were analyzed.The results show that as the open ratio increases,the MPW amplitude at the tunnel exit initially decreases before rising.At the open ratio of 2.28%,the slope of the ICW curve is linearly coincident with a supposed straight line in the ALM,which further reduces the MPW amplitude by 26.9%at 20 m and 20.0%at 50 m from the exit,as compared to the unvented hood.Therefore,the proposed method effectively mitigates MPW and quickly determines the upper limit of alleviation for the MPW amplitude at a fixed train-tunnel operation condition.All achievements provide a ne w potential measure for the adaptive design of tunnel hoods.
文摘Objective Peritoneal carcinomatosis(PC)is a common pattern of recurrence in gastric cancer patients and is associated with a poor prognosis.This study aimed to evaluate the predictive value of the albumin-fibrinogen ratio(AFR)for PC in patients with gastric cancer and to develop two preoperative prediction models.Methods A total of 745 gastric cancer patients were included in this study.Preoperative AFR,along with other serum markers and clinical tumor characteristics,was assessed.Univariate and multivariate logistic regression analyses were performed to determine the odds ratios(ORs)and 95%confidence intervals(CIs)of the independent variables.Propensity score matching(PSM)was used to control for potential confounders,and one-way ANOVA was conducted to evaluate differences in distribution between groups.Two prediction models incorporating the independent predictive indicators were constructed and validated via receiver operating characteristic(ROC)curves.Results Poorly differentiated type(OR 2.679;P=0.001),nondiffuse morphological type(OR 2.123;P=0.040),BMI<23.550 kg/m^(2)(OR 4.635;P=0.001),AFR<11.275(OR 2.895;P=0.003)and CA199≥73.615 U/mL(OR 2.040;P=0.037)were identified as independent risk factors for PC in patients with gastric cancer.After PSM,the AFR remained the only inflammatory marker that was independently associated with PC(P=0.003).AFR demonstrated consistent robustness in predicting PC across multiple sample sets.Among all the independent risk factors,the AFR had the highest area under the curve(AUC)for ROC analysis(AUC 0.648;95%CI 0.580–0.715).Two combination models incorporating the AFR demonstrated enhanced predictive ability:Combination Model 1(AUC 0.759;95%CI 0.699–0.820)and Combination Model 2(AUC 0.801;95%CI 0.744–0.859).Conclusions The preoperative AFR serves as a useful indicator for predicting PC.Two reliable prediction models based on the AFR have been developed.
基金Funded by the National Natural Science Foundation of China(No.52472012)Opening Project of State Silica-Based Materials Laboratory of Anhui Province(No.2022KF11)the Research and Development of Glass Powder for Laser Sealing and Its Sealing Technology(No.K24556)。
文摘The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum glazing.Under the condition of constant boron content,how the structure and properties vary with Bi/Si ratio in low-melting glass was investigated.In addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were revealed.The results show that a decrease in the Bi/Si ratio can cause a contraction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its coefficient of thermal expansion.During laser sealing,the copper ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the copper ions in the low-melting glass.The absorbance of the low-melting glass does not follow the expected correlation with the Bi/Si ratio,but shows a linear correlation with the content of divalent copper ions.The greater the concentration of divalent copper ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser sealing.The shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.
基金financially supported by the CITIC niobium steel development award Fund(M1656-2021)Central Iron and Steel Research Institute for its independent research and development fund(No.21G62460ZD).
文摘Increasing the hole expansion ratio is significant for developing high formability parts.Hole expansion tests were carried out on low carbon hot-rolled steel containing 0.11%Ti,0.072%Ti–0.03%Nb and 0.097%Ti–0.059%Nb,respectively.The effects of microstructure,texture,crack propagation behavior and second phase precipitation behavior on hole expansion ratio were investigated.The precipitation behavior of TiC and(Ti,Nb)C in austenite and ferrite in three groups of steel samples was calculated theoretically.The results showed that the hole expansion ratios of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 51.73%,51.17%and 66.24%following simulated coiling at 600℃,respectively.The microstructure was mainly polygonal ferrite with a small amount of pearlite.The grain refinement of 0.097Ti–0.059Nb test steel and the low texture ratio of{110}//ND improved the hole expansion ratio.The low overall hole expansion ratio was due to the microstructure inhomogeneity.The microstructure uniformity was improved by the quenching and tempering treatment,and the hole expansion ratio of the three test steels was greatly increased.The fastest precipitation temperatures in the austenitic region of 0.11Ti,0.072Ti–0.03Nb and 0.097Ti–0.059Nb test steels were 880,860 and 830℃,while those in the ferrite region were 680,675 and 675℃,respectively.The addition of Nb element increased the volume free energy,so that the critical core size of the nucleation on the dislocation line increased,resulting in the decrease in the fastest precipitation temperature.
