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Prediction and stratification for the surgical adverse events after minimally invasive esophagectomy:A two-center retrospective study
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作者 Qi-Hong Zhong Jiang-Shan Huang +7 位作者 Fei-Long Guo Jing-Yu Wu Mao-Xiu Yuan Jia-Fu Zhu Wen-Wei Lin Sui Chen Zhen-Yang Zhang Jiang-Bo Lin 《World Journal of Gastroenterology》 SCIE CAS 2025年第3期50-61,共12页
BACKGROUND Minimally invasive esophagectomy(MIE)is a widely accepted treatment for esophageal cancer,yet it is associated with a significant risk of surgical adverse events(SAEs),which can compromise patient recovery ... BACKGROUND Minimally invasive esophagectomy(MIE)is a widely accepted treatment for esophageal cancer,yet it is associated with a significant risk of surgical adverse events(SAEs),which can compromise patient recovery and long-term survival.Accurate preoperative identification of high-risk patients is critical for improving outcomes.AIM To establish and validate a risk prediction and stratification model for the risk of SAEs in patients with MIE.METHODS This retrospective study included 747 patients who underwent MIE at two centers from January 2019 to February 2024.Patients were separated into a train set(n=549)and a validation set(n=198).After screening by least absolute shrinkage and selection operator regression,multivariate logistic regression analyzed clinical and intraoperative variables to identify independent risk factors for SAEs.A risk stratification model was constructed and validated to predict the probability of SAEs.RESULTS SAEs occurred in 10.2%of patients in train set and 13.6%in the validation set.Patients with SAE had significantly higher complication rate and a longer hospital stay after surgery.The key independent risk factors identified included chronic obstructive pulmonary disease,a history of alcohol consumption,low forced expiratory volume in the first second,and low albumin levels.The stratification model has excellent prediction accuracy,with an area under the curve of 0.889 for the training set and an area under the curve of 0.793 for the validation set.CONCLUSION The developed risk stratification model effectively predicts the risk of SAEs in patients undergoing MIE,facilitating targeted preoperative interventions and improving perioperative management. 展开更多
关键词 Surgical adverse events Minimally invasive esophagectomy Esophageal cancer stratification model Perioperative management
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Prediabetes and atrial fibrillation risk stratification,phenotyping,and possible reversal to normoglycemia
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作者 Hyder O Mirghani 《World Journal of Diabetes》 SCIE 2025年第1期7-11,共5页
Patients admitted with prediabetes and atrial fibrillation are at high risk for major adverse cardiac or cerebrovascular events independent of confounding variables.The shared pathophysiology between these three serio... Patients admitted with prediabetes and atrial fibrillation are at high risk for major adverse cardiac or cerebrovascular events independent of confounding variables.The shared pathophysiology between these three serious but common diseases and their association with atherosclerotic cardiovascular risk factors establish a vicious circle culminating in high atherogenicity.Because of that,it is of paramount importance to perform risk stratification of patients with prediabetes to define phenotypes that benefit from various interventions.Furthermore,stress hyperglycemia assessment of hospitalized patients and consensus on the definition of prediabetes is vital.The roles lifestyle and metformin play in prediabetes are well established.However,the role of glucagon-like peptide agonists and metabolic surgery is less clear.Prediabetes is considered an intermediate between normoglycemia and diabetes along the blood glucose continuum.One billion people are expected to suffer from prediabetes by the year 2045.Therefore,realworld randomized controlled trials to assess major adverse cardiac or cerebrovascular event risk reduction and reversal/prevention of type 2 diabetes among patients are needed to determine the proper interventions. 展开更多
关键词 Major adverse cardiac or cerebrovascular event PREDIABETES Risk stratification PHENOTYPE Stress hyperglycemia Reversal to normoglycemia
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Risk stratification for radioactive iodine refractoriness using molecular alterations in distant metastatic differentiated thyroid cancer 被引量:2
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作者 Zhuanzhuan Mu Xin Zhang +9 位作者 Dongquan Liang Jugao Fang Ge Chen Wenting Guo Di Sun Yuqing Sun Zhentian Kai Lisha Huang Jun Liang Yansong Lin 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2024年第1期25-35,共11页
Objective: Patients with radioactive iodine-refractory differentiated thyroid cancer(RAIR-DTC) are often diagnosed with delay and constrained to limited treatment options. The correlation between RAI refractoriness an... Objective: Patients with radioactive iodine-refractory differentiated thyroid cancer(RAIR-DTC) are often diagnosed with delay and constrained to limited treatment options. The correlation between RAI refractoriness and the underlying genetic characteristics has not been extensively studied.Methods: Adult patients with distant metastatic DTC were enrolled and assigned to undergo next-generation sequencing of a customized 26-gene panel(Thyro Lead). Patients were classified into RAIR-DTC or non-RAIR groups to determine the differences in clinicopathological and molecular characteristics. Molecular risk stratification(MRS) was constructed based on the association between molecular alterations identified and RAI refractoriness, and the results were classified as high, intermediate or low MRS.Results: A total of 220 patients with distant metastases were included, 63.2% of whom were identified as RAIRDTC. Genetic alterations were identified in 90% of all the patients, with BRAF(59.7% vs. 17.3%), TERT promoter(43.9% vs. 7.4%), and TP53 mutations(11.5% vs. 3.7%) being more prevalent in the RAIR-DTC group than in the non-RAIR group, except for RET fusions(15.8% vs. 39.5%), which had the opposite pattern. BRAF and TERT promoter are independent predictors of RAIR-DTC, accounting for 67.6% of patients with RAIR-DTC. MRS was strongly associated with RAI refractoriness(P<0.001), with an odds ratio(OR) of high to low MRS of 7.52 [95%confidence interval(95% CI), 3.96-14.28;P<0.001] and an OR of intermediate to low MRS of 3.20(95% CI,1.01-10.14;P=0.041).Conclusions: Molecular alterations were associated with RAI refractoriness, with BRAF and TERT promoter mutations being the predominant contributors, followed by TP53 and DICER1 mutations. MRS might serve as a valuable tool for both prognosticating clinical outcomes and directing precision-based therapeutic interventions. 展开更多
关键词 Differentiated thyroid cancer distant metastases genetic alterations RAI refractoriness molecular risk stratification
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Failure mechanism and infrared radiation characteristic of hard siltstone induced by stratification effect 被引量:1
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作者 CHENG Yun SONG Zhanping +2 位作者 XU Zhiwei YANG Tengtian TIAN Xiaoxu 《Journal of Mountain Science》 SCIE CSCD 2024年第3期1058-1074,共17页
The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and tempora... The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass. 展开更多
关键词 Hard siltstone Failure mechanism stratification effect Infrared radiation characteristic Temporal-damage mechanism DISSIMILATION
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Stability of the Stratification of Water Bodies in the North Passage of the Yangtze River Estuary Based on the EFDC Model 被引量:1
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作者 WU De’an LI Xin WANG Yigang 《Journal of Ocean University of China》 CAS CSCD 2024年第1期23-32,共10页
To study the stratified stability of a water column in the North Passage of the Yangtze River Estuary,a numerical model of the hydrodynamics of this estuary is established using the EFDC model.On the basis of EFDC res... To study the stratified stability of a water column in the North Passage of the Yangtze River Estuary,a numerical model of the hydrodynamics of this estuary is established using the EFDC model.On the basis of EFDC results,this paper derives and pro-vides the discriminative index of water body stability caused by salinity and analyzes the along-range variation in water body strati-fication stability in the North Passage of the Yangtze River Estuary and the periodic variation at a key location(bend area)based on the simulation results of the numerical model.This work shows that the water body in the bend area varies between mixed and strati-fied types,and the vertical average flow velocity has a good negative correlation with the differential velocity between the surface and bottom layers of the water body.The model simulation results validate the formulae for the stratified stability discriminant during spring tides. 展开更多
关键词 Yangtze Estuary North Passage EFDC model stratification stability salinity distribution
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Stratification in central Bohai Sea and how it has shaped hypoxic events in summer
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作者 Jie Guo Diansheng Ji +3 位作者 Xiangyang Zheng Yanfang Li Haitian Tang Chawei Hou 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第9期93-104,共12页
In the last 10 years(2012-2021),five hypoxic events have been observed in summer in the central Bohai Sea(CBS).Frequent and persistent hypoxia will have an impact on the ecosystem of the CBS.In this paper,historical s... In the last 10 years(2012-2021),five hypoxic events have been observed in summer in the central Bohai Sea(CBS).Frequent and persistent hypoxia will have an impact on the ecosystem of the CBS.In this paper,historical sea temperature(ST),salinity(SAL),density(Den),and dissolved oxygen(DO)concentration data from three stations in the CBS are analyzed via the linear regression method,and the correlations between the stratification factors(ST,SAL,and Den)and DO concentration are determined.The thresholds of the stratification factors at the three stations in June in the year in which hypoxia occurred were determined and applied to survey data from 29 stations in late May to early June in 2022 in the CBS;this assessment found that the data from 19 stations indicated that hypoxia was about to occur.In August,the survey data showed that 14 out of the 29 stations indicated hypoxic conditions,of which 12 were from the predicted 19 stations,meaning that the estimation accuracy reached 63%.The same approach was applied to data from June 2023.The data for August from a bottom-type online monitoring system in the CBS verified the occurrence of hypoxic events around Sta.M2.The results show that the strength of the seawater stratification plays a leading role in hypoxic events in the summer in the CBS,and the thresholds of the stratification factors can be used to predict the occurrence of hypoxic events. 展开更多
关键词 hypoxia central Bohai Sea sea temperature SALINITY sea-water density stratification
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Modelling the temporal-varied nonlinear velocity profile of debris flow using a stratification aggregation algorithm in 3D-HBP-SPH framework
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作者 HAN Zheng XIE Wendu +5 位作者 ZENG Chuicheng LI Yange CHEN Guangqi CHEN Ningsheng HU Guisheng WANG Weidong 《Journal of Mountain Science》 SCIE CSCD 2024年第12期3945-3960,共16页
Estimation of velocity profile within mud depth is a long-standing and essential problem in debris flow dynamics.Until now,various velocity profiles have been proposed based on the fitting analysis of experimental mea... Estimation of velocity profile within mud depth is a long-standing and essential problem in debris flow dynamics.Until now,various velocity profiles have been proposed based on the fitting analysis of experimental measurements,but these are often limited by the observation conditions,such as the number of configured sensors.Therefore,the resulting linear velocity profiles usually exhibit limitations in reproducing the temporal-varied and nonlinear behavior during the debris flow process.In this study,we present a novel approach to explore the debris flow velocity profile in detail upon our previous 3D-HBPSPH numerical model,i.e.,the three-dimensional Smoothed Particle Hydrodynamic model incorporating the Herschel-Bulkley-Papanastasiou rheology.Specifically,we propose a stratification aggregation algorithm for interpreting the details of SPH particles,which enables the recording of temporal velocities of debris flow at different mud depths.To analyze the velocity profile,we introduce a logarithmic-based nonlinear model with two key parameters,that a controlling the shape of velocity profile and b concerning its temporal evolution.We verify the proposed velocity profile and explore its sensitivity using 34 sets of velocity data from three individual flume experiments in previous literature.Our results demonstrate that the proposed temporalvaried nonlinear velocity profile outperforms the previous linear profiles. 展开更多
关键词 Debris flow Velocity profile Temporal varied feature NONLINEAR stratification aggregation algorithm
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Convection and Stratification of Temperature and Concentration
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作者 Alexey Fedyushkin 《Fluid Dynamics & Materials Processing》 EI 2024年第6期1351-1364,共14页
This study is devoted to an analysis of natural convection and the emergence of delamination in an incompressible fluid encapsulated in a closed region heated from the side.Weak,medium and intensive modes of stationar... This study is devoted to an analysis of natural convection and the emergence of delamination in an incompressible fluid encapsulated in a closed region heated from the side.Weak,medium and intensive modes of stationary laminar thermal and thermo-concentration convection are considered.It is shown that nonlinear flow features can radically change the flow structure and characteristics of heat and mass transfer.Moreover,the temperature and concentration segregation in the center of the square region display a non-monotonic dependence on the Grashof number(flow intensity).The formation of a nonstationary periodic structure of thermal convection in boundary layers and in the core of a convective flow in the closed region is also examined.Details of the formation of countercurrents inside the region with the direction opposite to the main convective flow are given.Finally,the influence of vertical and horizontal vibrations on oscillatory convection is analyzed in detail. 展开更多
关键词 Natural convection stratification SEGREGATION numerical simulation vibrations
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Risk Stratification and Prognosis of Pulmonary Arterial Hypertension Associated with Congenital Heart Disease
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作者 Wenjie Dong Zhibin Hong +6 位作者 Aqian Wang Kaiyu Jiang Hai Zhu Fu zhang Zhaoxia Guo Hongling Su Yunshan Cao 《Congenital Heart Disease》 SCIE 2024年第3期325-339,共15页
Background:Current guidelines for managing pulmonary arterial hypertension(PAH)recommend a risk strati-fication approach.However,the applicability and accuracy of these strategies for PAH associated with congenital he... Background:Current guidelines for managing pulmonary arterial hypertension(PAH)recommend a risk strati-fication approach.However,the applicability and accuracy of these strategies for PAH associated with congenital heart disease(PAH-CHD)require further validation.This study aims to validate the reliability and predictive accuracy of a simplified stratification strategy for PAH-CHD patients over a three-year follow-up.Additionally,new prognostic variables are identified and novel risk stratification methods are developed for assessing and managing PAH-CHD patients.Methods:This retrospective study included 126 PAH-CHD patients.Clinical and biochemical variables across risk groups were assessed using Kruskal-Wallis and Fisher’s exact tests.Indepen-dent risk factors were identified using ordered logistic regression,while Kaplan-Meier and Cox proportional hazards regression analyses evaluated their impact on all-cause mortality.A new stratification model for the PAH-CHD population was constructed based on these analyses.Results:Significant survival differences across stratified risk groups were observed(p<0.001),validating the effectiveness of the simplified risk stratification method in PAH-CHD patients.Prothrombin activity was a strong independent predictor of adverse outcomes of PAH-CHD patients(Hazard ratio 0.95,p<0.001,C-index 0.70).A model combining N-terminal pro-brain natriuretic peptide,prothrombin activity,albumin,and right atrial area achieved an area under the curve of 0.89 and a C-index of 0.85.Conclusions:The simplified risk stratification method is applicable to PAH-CHD patients.Prothrombin activity is a strong independent predictor of adverse outcomes.A comprehensive risk stratification approach,incorporating both established and novel biomarkers,enhances accessibility and offers predictive efficacy during follow-up for PAH-CHD patients,comparable to established models. 展开更多
关键词 Pulmonary hypertension pulmonary arterial hypertension congenital heart disease risk stratification
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Deep learning model combined with computed tomography features to preoperatively predicting the risk stratification of gastrointestinal stromal tumors
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作者 Yi Li Yan-Bei Liu +4 位作者 Xu-Bin Li Xiao-Nan Cui Dong-Hua Meng Cong-Cong Yuan Zhao-Xiang Ye 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第12期4663-4674,共12页
BACKGROUND Gastrointestinal stromal tumors(GIST)are prevalent neoplasm originating from the gastrointestinal mesenchyme.Approximately 50%of GIST patients experience tumor recurrence within 5 years.Thus,there is a pres... BACKGROUND Gastrointestinal stromal tumors(GIST)are prevalent neoplasm originating from the gastrointestinal mesenchyme.Approximately 50%of GIST patients experience tumor recurrence within 5 years.Thus,there is a pressing need to accurately evaluate risk stratification preoperatively.AIM To assess the application of a deep learning model(DLM)combined with computed tomography features for predicting risk stratification of GISTs.METHODS Preoperative contrast-enhanced computed tomography(CECT)images of 551 GIST patients were retrospectively analyzed.All image features were independently analyzed by two radiologists.Quantitative parameters were statistically analyzed to identify significant predictors of high-risk malignancy.Patients were randomly assigned to the training(n=386)and validation cohorts(n=165).A DLM and a combined DLM were established for predicting the GIST risk stratification using convolutional neural network and subsequently evaluated in the validation cohort.RESULTS Among the analyzed CECT image features,tumor size,ulceration,and enlarged feeding vessels were identified as significant risk predictors(P<0.05).In DLM,the overall area under the receiver operating characteristic curve(AUROC)was 0.88,with the accuracy(ACC)and AUROCs for each stratification being 87%and 0.96 for low-risk,79%and 0.74 for intermediate-risk,and 84%and 0.90 for high-risk,respectively.The overall ACC and AUROC were 84%and 0.94 in the combined model.The ACC and AUROCs for each risk stratification were 92%and 0.97 for low-risk,87%and 0.83 for intermediate-risk,and 90%and 0.96 for high-risk,respectively.Differences in AUROCs for each risk stratification between the two models were significant(P<0.05).CONCLUSION A combined DLM with satisfactory performance for preoperatively predicting GIST stratifications was developed using routine computed tomography data,demonstrating superiority compared to DLM. 展开更多
关键词 Gastrointestinal stromal tumors Deep learning Risk stratification Tomography X-ray computed PROGNOSIS
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Magnetic resonance imaging-based radiomics model for preoperative assessment of risk stratification in endometrial cancer
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作者 Zhi-Yao Wei Zhe Zhang +2 位作者 Dong-Li Zhao Wen-Ming Zhao Yuan-Guang Meng 《World Journal of Clinical Cases》 SCIE 2024年第26期5908-5921,共14页
BACKGROUND Preoperative risk stratification is significant for the management of endometrial cancer(EC)patients.Radiomics based on magnetic resonance imaging(MRI)in combination with clinical features may be useful to ... BACKGROUND Preoperative risk stratification is significant for the management of endometrial cancer(EC)patients.Radiomics based on magnetic resonance imaging(MRI)in combination with clinical features may be useful to predict the risk grade of EC.AIM To construct machine learning models to predict preoperative risk stratification of patients with EC based on radiomics features extracted from MRI.METHODS The study comprised 112 EC patients.The participants were randomly separated into training and validation groups with a 7:3 ratio.Logistic regression analysis was applied to uncover independent clinical predictors.These predictors were then used to create a clinical nomogram.Extracted radiomics features from the T2-weighted imaging and diffusion weighted imaging sequences of MRI images,the Mann-Whitney U test,Pearson test,and least absolute shrinkage and selection operator analysis were employed to evaluate the relevant radiomic features,which were subsequently utilized to generate a radiomic signature.Seven machine learning strategies were used to construct radiomic models that relied on the screening features.The logistic regression method was used to construct a composite nomogram that incorporated both the radiomic signature and clinical independent risk indicators.RESULTS Having an accuracy of 0.82 along with an area under the curve(AUC)of 0.915[95%confidence interval(CI):0.806-0.986],the random forest method trained on radiomics characteristics performed better than expected.The predictive accuracy of radiomics prediction models surpassed that of both the clinical nomogram(AUC:0.75,95%CI:0.611-0.899)and the combined nomogram(AUC:0.869,95%CI:0.702-0.986)that integrated clinical parameters and radiomic signature.CONCLUSION The MRI-based radiomics model may be an effective tool for preoperative risk grade prediction in EC patients. 展开更多
关键词 Endometrial cancer Risk stratification Radiomics Machine learning NOMOGRAM
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Analyzing Thermal Stratification and Nanoparticle Shapes Influence on an EMHD Ternary Nanofluid Flow amidst Two Spinning Disks
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作者 Muhammad Ramzan Saima Riasat 《Journal of Applied Mathematics and Physics》 2024年第8期3017-3025,共9页
The present study examines the thermal distribution of ternary nanofluid flow amid two spinning disks influenced by electric and magnetic fields. Keeping in view the shape of the particles, the electrically conducting... The present study examines the thermal distribution of ternary nanofluid flow amid two spinning disks influenced by electric and magnetic fields. Keeping in view the shape of the particles, the electrically conducting ternary nanofluid is analyzed with variable thermophysical features. Three types of nanoparticles namely Copper, Aluminum Oxide, and Graphene with spherical, cylindrical, and platelet shapes are taken respectively and are immersed in a (50-50)% ratio of water and ethylene glycol mixture which acts as a base fluid. The anticipated problem is addressed by employing a reliable and user-friendly numerical bvp4c built-in collocation scheme. This solution is then showcased through illustrations and tables. Strengthening the radiation results in an enhanced heat transfer rate. Radial and azimuthal velocities once rotation of disks is enhanced. The key findings provide a strong theoretical background in photovoltaic cells, solar collectors, radiators, solar water heaters, and many other applications. 展开更多
关键词 Trihybrid Nanofluid Flow Thermal stratification Particle Shapes Spin-ning Disks
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Developing crop specific area frame stratifications based on geospatial crop frequency and cultivation data layers 被引量:5
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作者 Claire G. Boryan Zhengwei Yang +1 位作者 Patrick Willis Liping Di 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第2期312-323,共12页
Area Sampling Frames (ASFs) are the basis of many statistical programs around the world. To improve the accuracy, objectivity and efficiency of crop survey estimates, an automated stratification method based on geos... Area Sampling Frames (ASFs) are the basis of many statistical programs around the world. To improve the accuracy, objectivity and efficiency of crop survey estimates, an automated stratification method based on geospatial crop planting frequency and cultivation data is proposed. This paper investigates using 2008-2013 geospatial corn, soybean and wheat planting frequency data layers to create three corresponding single crop specific and one multi-crop specific South Dakota (SD) U.S. ASF stratifications. Corn, soybeans and wheat are three major crops in South Dakota. The crop specific ASF stratifications are developed based on crop frequency statistics derived at the primary sampling unit (PSU) level based on the Crop Frequency Data Layers. The SD corn, soybean and wheat mean planting frequency strata of the single crop stratifications are substratified by percent cultivation based on the 2013 Cultivation Layer. The three newly derived ASF stratifications provide more crop specific information when compared to the current National Agricultural Statistics Service (NASS) ASF based on percent cultivation alone. Further, a multi-crop stratification is developed based on the individual corn, soybean and wheat planting frequency data layers. It is observed that all four crop frequency based ASF stratifications consistently predict corn, soybean and wheat planting patterns well as verified by the 2014 Farm Service Agency (FSA) Common Land Unit (CLU) and 578 administrative data. This demonstrates that the new stratifications based on crop planting frequency and cultivation are crop type independent and applicable to all major crops. Further, these results indicate that the new crop specific ASF stratifications have great potential to improve ASF accuracy, efficiency and crop estimates. 展开更多
关键词 cropland data layer crop planting frequency data layers automated stratification crop specific stratification multi-crop stratification
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Organic carbon stratification and size distribution of three typical paddy soils from Taihu Lake region,China 被引量:21
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作者 PAN Genxing WU Laosheng +3 位作者 LI Lianqing ZHANG Xuhui GONG Wei WOOD Yvonne 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第4期456-463,共8页
Developing realistic soil carbon (C) sequestration strategies for China's sustainable agriculture relies on accurate estimates of the amount, retention and turnover rates of C stored in paddy soils. Available C est... Developing realistic soil carbon (C) sequestration strategies for China's sustainable agriculture relies on accurate estimates of the amount, retention and turnover rates of C stored in paddy soils. Available C estimates to date are predominantly for the tilled and flood-irrigated surface topsoil (ca. 30 cm). Such estimates cannot be used to extrapolate to soil depths of 100 cm since soil organic carbon (SOC) generally shows a sharp decrease with depth. In this research, composite soil samples were collected at several depths to 100 cm from three representative paddy soils in the Taihu Lake region, China. Soil organic carbon distribution in the profiles and in aggregate-size fractions was determined. Results showed that while SOC decreased exponentially with depth to 100 cm, a substantial proportion of the total SOC (30%-40%) is stored below the 30 cm depth. In the carbon-enriched paddy topsoils, SOC was found to accumulate preferentially in the 2-0.25 and 0.25-0.02 mm aggregate size fractions. δ^13C analysis of the coarse micro-aggregate fraction showed that the high degree of C stratification in the paddy topsoil was in agreement with the occurrence of lighter δ^1313C in the upper 30 cm depth. These results suggest that SOC stratification within profiles varies with different pedogenetical types of paddy soils with regards to clay and iron oxyhydrates distributions. Sand-sized fractions of aggregates in paddy soil systems may play a very important role in carbon sequestration and turnover, dissimilar to other studied agricultural systems. 展开更多
关键词 profile stratification organic carbon paddy soils size fractions soil aggregates carbon storage
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The effect of a seasonal stratification variation on the load exerted by internal solitary waves on a cylindrical pile 被引量:13
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作者 CAI Shuqun XU Jiexin +3 位作者 CHEN Zhiwu XIE Jieshuo DENG Xiaodong LV Haibin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第7期21-26,共6页
On the basis of Morison's empirical formula and modal separation method in estimating the force and torque exerted by internal solitary waves (ISWs) on a cylindrical pile, it is found that the loads exerted by the ... On the basis of Morison's empirical formula and modal separation method in estimating the force and torque exerted by internal solitary waves (ISWs) on a cylindrical pile, it is found that the loads exerted by the ISWs change largely in different seasons at the same site of the continental shelf in the South China Sea (SCS) even under the condition that the amplitudes of ISWs are the same. Thus, the effect of a seasonal water stratification variation on the force and torque exerted by the ISWs is investigated, and a three-parameter stratification model is employed. It is shown that the loads exerted by the ISWs depend largely on the wa- ter stratification. The stronger the water stratification, the larger the force and the torque; when the depth where the maximum thermocline appears is deepened, the force decreases but the torque increases; when the width of the thermocline is narrowed, the force increases but the torque decreases. The seasonal varia- tion of the force and the torque exerted by the ISWs in four seasons in the SCS is thus explained. Key words: internal solitary waves, force, torque, water stratification, South China Sea 展开更多
关键词 internal solitary waves force TORQUE water stratification South China Sea
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Frailty and cardiovascular disease: potential role of gait speed in surgical risk stratification in older adults 被引量:12
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作者 Michael A. Chen 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2015年第1期44-56,共13页
Frailty is a state of late life decline and vulnerability, typified by physical weakness and decreased physiologic reserve. The epidemiology and pathophysiology of frailty share features with those of cardiovascular d... Frailty is a state of late life decline and vulnerability, typified by physical weakness and decreased physiologic reserve. The epidemiology and pathophysiology of frailty share features with those of cardiovascular disease. Gait speed can be used as a measure of frailty and is a powerful predictor of mortality. Advancing age is a potent risk factor for cardiovascular disease and has been associated with an increased risk of adverse outcomes. Older adults comprise approximately half of cardiac surgery patients, and account for nearly 80% of the major complications and deaths following surgery. The ability of traditional risk models to predict mortality and major morbidity in older patients being considered for cardiac surgery may improve if frailty, as measured by gait speed, is included in their assessment. It is possible that in the future frailty assessment may assist in choosing among therapies (e.g., surgical vs. percutaneous aortic valve replacement for patients with aortic stenosis). 展开更多
关键词 Cardiac surgery FRAILTY Gait speed Risk scores Risk stratification
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Risk stratification for ST segment elevation myocardial infarction in the era of primary percutaneous coronary intervention 被引量:6
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作者 Richard A Brogan Christopher J Malkin +3 位作者 Philip D Batin Alexander D Simms James M McLenachan Christopher P Gale 《World Journal of Cardiology》 CAS 2014年第8期865-872,共8页
Acute coronary syndromes presenting with ST elevation are usually treated with emergency reperfusion/revascularisation therapy. In contrast current evidence and national guidelines recommend risk stratification for no... Acute coronary syndromes presenting with ST elevation are usually treated with emergency reperfusion/revascularisation therapy. In contrast current evidence and national guidelines recommend risk stratification for non ST segment elevation myocardial infarction(NSTEMI) with the decision on revascularisation dependent on perceived clinical risk. Risk stratification for STEMI has no recommendation. Statistical risk scoring techniques in NSTEMI have been demonstrated to improve outcomes however their uptake has been poor perhaps due to questions over their discrimination and concern for application to individuals who may not have been adequately represented in clinical trials. STEMI is perceived to carry sufficient risk to warrant emergency coronary intervention [by primary percutaneous coronary intervention(PPCI)] even if this results in a delay to reperfusion with immediate thrombolysis. Immediate thrombolysis may be as effective in patients presenting early, or at low risk, but physicians are poor at assessing clinical and procedural risks and currently are not required to consider this. Inadequate data on risk stratification in STEMI inhibits the option of immediate fibrinolysis, which may be cost-effective. Currently the mode of reperfusion for STEMI defaults to emergency angiography and percutaneous coronary intervention ignoring alternative strategies. This review article examines the current risk scores and evidence base for risk stratification for STEMI patients. The requirements for an ideal STEMI risk score are discussed. 展开更多
关键词 ST segment elevation myocardial INFARCTION RISK stratification Primary PERCUTANEOUS coronary intervention HARM RISK SCORES
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A numerical study on salinity stratification at the Oujiang River Estuary, China 被引量:4
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作者 Yichun Li Jingui Liu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第11期40-50,共11页
The Oujiang River Estuary(ORE)is a macrotidal estuary with drastic variation of river discharge and large tidal range.Numerical simulations based on the unstructured grid,Finite-Volume,primitive equation Community Oce... The Oujiang River Estuary(ORE)is a macrotidal estuary with drastic variation of river discharge and large tidal range.Numerical simulations based on the unstructured grid,Finite-Volume,primitive equation Community Ocean Model(FVCOM)are conducted to investigate the intratidal and intertidal variations of salinity with an extremely upstream river boundary and large computational domain.The dynamic equation of potential energy anomaly is adopted to evaluate the stratification and mixing processes from model results.Meanwhile,the stability of estuarine stratification on different timescales and its spatial variation are studied using estuarine Richardson number and stratification parameter.The critical values of tidal range and river discharge that determine the stratification state are obtained.The critical values exhibit distinct spatial difference.The north branch of the ORE exhibits well-mixed conditions when the tidal range exceeds 3.8,4.0 and 4.6m at upper inlet,middle segment and the river mouth,respectively.When river discharge is below 280 m^3/s or exceeds 510 m^3/s,the upper part of the north branch is well-mixed sustainably.Near the river mouth,river discharge of 280 m^3/s is a rough critical value that separates well-mixed and stratified states.It is also concluded that periodic stratification exists in the North Channel.The lower estuary appears to be partially stratified at early ebb or early flood tide,and well-mixed in other tidal stages.The stratification only develops during early ebb in the upper segment.The enhancement of stratification is mainly caused by longitudinal advection and lateral velocity shear,while turbulent mixing and longitudinal tidal strain are the main factors of stratification attenuation. 展开更多
关键词 stratification the Oujiang River ESTUARY FVCOM MACROTIDAL ESTUARY potential energy ANOMALY
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Thermal stratification level of low sidewall air supply with air-conditioning system in large space 被引量:3
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作者 黄晨 蔡宁 高雪垒 《Journal of Central South University》 SCIE EI CAS 2009年第S1期166-170,共5页
The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simu... The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simulation. Based on the simulation of experiment condition,the air velocity and vertical temperature distribution in a large space were simulated at different air-outlet velocities,and then the thermal stratification level line was obtained. The simulation results well match with the experimental ones and the average relative error is 3.4%. The thermal stratification level is heightened by increasing the air-outlet velocity with low sidewall air supply mode. It is concluded that when air-outlet velocity is 0.29 m/s,which is the experimental case,a uniform thermal environment in the higher occupied zone and a stable stratification level are formed. When the air-outlet velocity is low,such as 0.05 m/s,the thermal stratification level is too low and the air velocity is too small to meet the human thermal comfort in the occupied zone. So,it would be reasonable that the air-outlet velocity may be designed as 0.31 m/s if the height of the occupied zone is 2 m. 展开更多
关键词 large space low SIDEWALL AIR supply thermal stratification LEVEL numerical simulation air-outlet VELOCITY
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Evaluation of high-risk factors and the diagnostic value of alpha-fetoprotein in the stratification of primary liver cancer 被引量:5
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作者 Hong-Bin Jiao Wei Wang +5 位作者 Meng-Nan Guo Ya-Li Su De-Quan Pang Bao-Lin Wang Jun Shi Jing-Hua Wu 《World Journal of Clinical Cases》 SCIE 2022年第26期9264-9275,共12页
BACKGROUND Alpha-fetoprotein(AFP)is one of the diagnostic standards for primary liver cancer(PLC);however,AFP exhibits insufficient sensitivity and specificity for diagnosing PLC.AIM To evaluate the effects of high-ri... BACKGROUND Alpha-fetoprotein(AFP)is one of the diagnostic standards for primary liver cancer(PLC);however,AFP exhibits insufficient sensitivity and specificity for diagnosing PLC.AIM To evaluate the effects of high-risk factors and the diagnostic value of AFP in stratified PLC.METHODS In total,289 PLC cases from 2013 to 2019 were selected for analysis.First,the contributions of high-risk factors in stratifying PLC were compared according to the following criteria:Child–Pugh score,clinical stage of liver cirrhosis,tumor size,and Barcelona Clinic Liver Cancer(BCLC)stage.Then,the diagnostic value of AFP was evaluated in different stratifications of PLC by receiver operating characteristic curves.For PLC cases in which AFP played little role,the diagnostic values of carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA 19-9),gamma-glutamyl transferase(GGT),and AFP were analyzed.RESULTS The roles of high-risk factors differed in stratified PLC.The incidence of smoking and drinking history was higher in PLC with Child–Pugh scores of C(P<0.0167).The hepatitis B virus(HBV)infection rate in PLC with cirrhosis was more than in PLC without cirrhosis(P<0.0167).Small tumors were more prone to cirrhosis than large tumors(P<0.005).BCLC stage D PLC was more likely to be associated with HBV infection and cirrhosis(P<0.0083).AFP levels were higher in PLC with cirrhosis,diffuse tumors,and BCLC stage D disease.In diagnosing PLC defined as Child–Pugh A,B,and C,massive hepatoma,diffuse hepatoma,BCLC stage B,C,and D,and AFP showed significant diagnostic value[all area under the curve(AUC)>0.700].However,these measures were meaningless(AUC<0.600)in small hepatomas and BCLC A stage PLC,but could be replaced by the combined detection of CEA,CA 19-9,GGT,and AFP(AUC=0.810 and 0.846,respectively).CONCLUSION Stratification of PLC was essential for precise diagnoses and benefited from evaluating AFP levels. 展开更多
关键词 Primary liver cancer stratification Risk factors ALPHA-FETOPROTEIN Receiver operating characteristic curve DIAGNOSTICS
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