期刊文献+
共找到6,188篇文章
< 1 2 250 >
每页显示 20 50 100
Prevalence and associated risk factors of Helicobacter pylori infection in community households in Lanzhou city
1
作者 Ju-Kun Zhou Ya Zheng +1 位作者 Yu-Ping Wang Rui Ji 《World Journal of Gastroenterology》 SCIE CAS 2024年第47期5018-5031,共14页
BACKGROUND Helicobacter pylori(H.pylori)infection exhibits a familial clustering phenomenon.AIM To investigate the prevalence of H.pylori infection,identify associated factors,and analyze patterns of transmission with... BACKGROUND Helicobacter pylori(H.pylori)infection exhibits a familial clustering phenomenon.AIM To investigate the prevalence of H.pylori infection,identify associated factors,and analyze patterns of transmission within families residing in the community.METHODS From July 2021 to September 2021,a total of 191 families(519 people)in two randomly chosen community health service centers in the Chengguan District of Lanzhou in Gansu Province,were recruited to fill out questionnaires and tested for H.pylori infection.Individuals were followed up again from April 2023 and June 2023 to test for H.pylori infection.The relationship between variables and H.pylori infection was analyzed using logistic regression and generalized linear mixed models.RESULTS In 2021,the individual-based H.pylori infection rate was found to be 47.0%(244/519),which decreased to 38.1%(177/464)in 2023.Additionally,the rate of individual-based H.pylori new infection was 22.8%(55/241).The family-based H.pylori infection rate in 2021 was 76.9%(147/191),which decreased to 67.1%(116/173)in 2023,and the rate of family-based H.pylori new infection was 38.6%(17/44).Individual H.pylori infection was positively correlated with age,body mass index(BMI),eating food that was excessively hot,frequent acid reflux,bloating,and halitosis symptoms,and negatively correlated with family size and nut consumption.New individual H.pylori infection was positively correlated with BMI,other types of family structures,drinking purified water,and frequent heartburn symptoms,while negatively correlated with the use of refrigerators and following a regular eating schedule.A larger living area was an independent protective factor for H.pylori infection in households.Frequently consuming excessively hot food and symptoms of halitosis were independent risk factors for H.pylori infection in individuals;frequent consumption of nuts was an independent protective factor for H.pylori infection.Other types of family structure,drinking purified water,and frequent heartburn symptoms were independent risk factors for new individual H.pylori infection;the use of a refrigerator was an independent protective factor for new H.pylori infections.CONCLUSION The household H.pylori infection rate in Lanzhou is relatively high and linked to socio-demographic factors and lifestyles.Eradication efforts and control of related risk factors are recommended in the general population. 展开更多
关键词 Helicobacter pylori HOUSEHOLD China PREVALENCE Risk factors
下载PDF
Changes in human settlement environments and their drivers in valley cities located in arid and semi-arid regions:A case study of Lanzhou in Western China
2
作者 Rong Zhu YouYan Jiang +1 位作者 Bo Wang YaHui Zhang 《Research in Cold and Arid Regions》 CSCD 2024年第3期149-158,共10页
Development of urban human settlement environments(HSEs)is an integral part of promoting high-quality and sustainable regional development and constructing a beautiful China.The city of Lanzhou,located at the geometri... Development of urban human settlement environments(HSEs)is an integral part of promoting high-quality and sustainable regional development and constructing a beautiful China.The city of Lanzhou,located at the geometric center of China,is the only provincial capital traversed by the Yellow River.Given the constraints posed by the valley topography and the need for economic development,the development of this HSE,which is located within an arid region,poses considerable challenges.Evidently,an understanding of the evolution of HSEs and drivers of changes in them contributes to high-quality,sustainable urban development in arid and semi-arid regions.An analytical model was developed using the parameters of relief degree of land surface,human comfort days,the land cover index,nighttime light index,and precipitation.This model was used in combination with population density and the gross domestic product to analyze the spatial distribution of Lanzhou's HSE and its drivers.The results showed that landscapes in Lanzhou underwent significant changes between 2000 and 2022,with an increase in building-up land(+0.946%),cultivated land(+0.134%),and forest land(+0.018%)and a decrease in grassland(-1.10%).There was significant outward expansion of the main urban zone of Lanzhou and of various county towns,with the increase in building-up land being most prominent.During this period,there were significant changes in the periphery of the core urban area and county towns in Lanzhou,with decreases moving from the urban center(the highest value)to the surrounding areas(Yongdeng County had the lowest value).The correlation between the HSE and population density grew stronger in Anning and Chengguan Districts but became weaker in Xigu and Qilihe Districts.Spatiotemporal variations in the HSE were primarily caused by climate change,followed by human activities,and were also influenced by the valley topography.Overall,the spatial distribution of population density and the HSE in Lanzhou demonstrated good consistency under the in-fluence of economic development and urbanization. 展开更多
关键词 Human settlement environment Vegetation index Nighttime light index Human comfort days
下载PDF
Study on the Influence of Lanzhou-Urumqi High-Speed Railway on Regional Accessibility and Economic Development
3
作者 Lili Ma Xiaolong Han Miao Gong 《Proceedings of Business and Economic Studies》 2024年第2期22-31,共10页
The Lanzhou-Urumqi high-speed railway is an important part of the railway network connecting Gansu,Qinghai,and Xinjiang,and it is of far-reaching significance in facilitating China’s western development.An accessibil... The Lanzhou-Urumqi high-speed railway is an important part of the railway network connecting Gansu,Qinghai,and Xinjiang,and it is of far-reaching significance in facilitating China’s western development.An accessibility model and a double difference model were built to analyze the impact of the Lanzhou-Urumqi high-speed railway on regional accessibility and economic development of the areas along the line before(2012-2014)and after(2017-2019)its opening.The results show that the regional accessibility remains unchanged before and after the operation of this railway line.However,there is a spatial difference in improvement,that of central cities being better.The opening of the high-speed railway is conducive to driving the overall economic development of the region and promoting the comprehensive and coordinated development of regional economies. 展开更多
关键词 Lanzhou-Urumqi high-speed railway Regional economy Double difference model Accessibility model Empirical analysis
下载PDF
Interleukin-17A facilitates tumor progression via upregulating programmed death ligand-1 expression in hepatocellular carcinoma
4
作者 Zhong-Xia Yang Li-Ting Zhang +2 位作者 Xiao-Jun Liu Xue-Bin Peng Xiao-Rong Mao 《World Journal of Gastrointestinal Oncology》 SCIE 2025年第1期176-198,共23页
BACKGROUND Hepatocellular carcinoma(HCC)is an inflammation-associated tumor with a dismal prognosis.Immunotherapy has become an important treatment strategy for HCC,as immunity is closely related to inflammation in th... BACKGROUND Hepatocellular carcinoma(HCC)is an inflammation-associated tumor with a dismal prognosis.Immunotherapy has become an important treatment strategy for HCC,as immunity is closely related to inflammation in the tumor microenvir-onment.Inflammation regulates the expression of programmed death ligand-1(PD-L1)in the immunosuppressive tumor microenvironment and affects im-munotherapy efficacy.Interleukin-17A(IL-17A)is involved in the remodeling of the tumor microenvironment and plays a protumor or antitumor role in different tumors.We hypothesized that IL-17A participates in tumor progression by affe-cting the level of immune checkpoint molecules in HCC.The upregulation of PD-L1 expression in HCC cells by IL-17A was assessed by reverse transcription PCR,western blotting,and flow cytometry.Mechanistic studies were conducted with gene knockout models and pathway inhibitors.The function of IL-17A in immune evasion was explored through coculture of T cells and HCC cells.The effects of IL-17A on the malignant biological behaviors of HCC cells were evaluated in vitro,and the antitumor effects of an IL-17A inhibitor and its synergistic effects with a PD-L1 inhibitor were studied in vivo.RESULTS IL-17A upregulated PD-L1 expression in HCC cells in a dose-dependent manner,whereas IL-17A receptor knockout or treatment with a small mothers against decapentaplegic 2 inhibitor diminished the PD-L1 expression induced by IL-17A.IL-17A enhanced the survival of HCC cells in the coculture system.IL-17A increased the viability,G2/M ratio,and migration of HCC cells and decreased the apoptotic index.Cyclin D1,VEGF,MMP9,and Bcl-1 expression increased after IL-17A treatment,whereas BAX expression decreased.The combination of IL-17A and PD-L1 inhibitors showed synergistic antitumor efficacy and increased cluster of differentiation 8+T lymphocyte infiltration in an HCC mouse model.CONCLUSION IL-17A upregulates PD-L1 expression via the IL-17A receptor/phosphorylation-small mothers against decapenta-plegic 2 signaling pathway in HCC cells.Blocking IL-17A enhances the therapeutic efficacy of PD-L1 antibodies in HCC in vivo. 展开更多
关键词 INTERLEUKIN-17A Programmed death ligand-1 Interleukin-17A receptor Small mothers against decapentaplegic 2 Hepatocellular carcinoma IMMUNOTHERAPY
下载PDF
Structural Modal Parameter Recognition and Related Damage Identification Methods under Environmental Excitations: A Review
5
作者 Chao Zhang Shang-Xi Lai Hua-Ping Wang 《Structural Durability & Health Monitoring》 EI 2025年第1期25-54,共30页
Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters accordi... Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientific basis for structural damage identification and dynamic model modification.In view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and briefly describes how to identify structural damages based on the derived modal parameters.The paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),briefly describes damage identification methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artificial intelligence(AI)methods in the direction of modal parameter recognition and damage identification is further discussed.Based on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identification methods are given to provide scientific references for the optimized design and functional upgrading of SHM systems. 展开更多
关键词 Structural health monitoring data information modal parameters damage identification AI method
下载PDF
Neuroprotective potential for mitigating ischemia-reperfusion-induced damage
6
作者 Zi Ye Runqing Liu +6 位作者 Hangxing Wang Aizhen Zuo Cen Jin Nan Wang Huiqi Sun Luqian Feng Hua Yang 《Neural Regeneration Research》 SCIE CAS 2025年第8期2199-2217,共19页
Reperfusion following cerebral ischemia causes both structural and functional damage to brain tissue and could aggravate a patient's condition;this phenomenon is known as cerebral ischemia-reperfusion injury.Curre... Reperfusion following cerebral ischemia causes both structural and functional damage to brain tissue and could aggravate a patient's condition;this phenomenon is known as cerebral ischemia-reperfusion injury.Current studies have elucidated the neuroprotective role of the sirtuin protein family(Sirtuins)in modulating cerebral ischemia-reperfusion injury.However,the potential of utilizing it as a novel intervention target to influence the prognosis of cerebral ischemia-reperfusion injury requires additional exploration.In this review,the origin and research progress of Sirtuins are summarized,suggesting the involvement of Sirtuins in diverse mechanisms that affect cerebral ischemia-reperfusion injury,including inflammation,oxidative stress,blood-brain barrier damage,apoptosis,pyroptosis,and autophagy.The therapeutic avenues related to Sirtuins that may improve the prognosis of cerebral ischemia-reperfusion injury were also investigated by modulating Sirtuins expression and affecting representative pathways,such as nuclear factor-kappa B signaling,oxidative stress mediated by adenosine monophosphate-activated protein kinase,and the forkhead box O.This review also summarizes the potential of endogenous substances,such as RNA and hormones,drugs,dietary supplements,and emerging therapies that regulate Sirtuins expression.This review also reveals that regulating Sirtuins mitigates cerebral ischemia-reperfusion injury when combined with other risk factors.While Sirtuins show promise as a potential target for the treatment of cerebral ischemiareperfusion injury,most recent studies are based on rodent models with circadian rhythms that are distinct from those of humans,potentially influencing the efficacy of Sirtuinstargeting drug therapies.Overall,this review provides new insights into the role of Sirtuins in the pathology and treatment of cerebral ischemia-reperfusion injury. 展开更多
关键词 apoptosis autophagy blood-brain barrier dietary supplements drug HORMONES inflammation NEUROPROTECTION oxidative stress prognosis PYROPTOSIS reperfusion injury risk factors RNA THERAPEUTICS
下载PDF
Boron-containing copolymers as environmentally friendly lubricant additives
7
作者 Hua Xue Fengchun Liang +4 位作者 Weili Yang Qun He Meirong Cai Feng Zhou Weifeng Bu 《日用化学工业(中英文)》 北大核心 2025年第1期1-11,共11页
Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubri... Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubricant additives,their macromolecular analogs have been rarely considered yet to develop environmentally friendly lubricant additives.In this work,a series of boron-containing copolymers have been synthesized by free-radical copolymerization of stearyl methacrylate and isopropenyl boronic acid pinacol ester with different feeding ratios(S_(n)-r-B_(m),n=1,m=1/3,1,2,3,5,9).The resulting copolymers of S_(n)-r-B_(m)(n=1,m=1/3,1,2,3,5)are readily dispersed in the PAO-10 base oil and form micelle-like aggregates with hydrodynamic diameters ranging from 9.7 to 52 nm.SRV-IV oscillating reciprocating tribological tests on ball-on-flat steel pairs show that compared with the base oil of PAO-10,the friction coefficients and wear volumes of the base oil solutions of S_(n)-r-B_(m)decrease considerably up to 62%and 97%,respectively.Moreover,the base oil solution of S_(1)-r-B_(1)exhibits an excellent load-bearing capacity of(850±100)N.These superior lubricating properties are due to the formation of protective tribofilms comprising S_(n)-r-B_(m),boron oxide,and iron oxide compounds on the lubricated steel surface.Therefore,the boron-containing copolymers can be regarded as a novel class of environmentally friendly lubricating oil macroadditives for efficient friction and wear reduction without sulfur and phosphorus elements. 展开更多
关键词 friction and wear reduction lubricant additives boron-containing copolymers POLYMERIZATION
下载PDF
Hepatic hemangiomas mimicking gastrointestinal stromal tumors: A case report
8
作者 Ji-Ze Wang Hao Chen 《World Journal of Clinical Cases》 2025年第11期66-71,共6页
BACKGROUND Hepatic hemangiomas can be challenging to diagnose,particularly when they present with atypical features that mimic other conditions,such as gastrointestinal stromal tumors(GISTs).This case highlights the d... BACKGROUND Hepatic hemangiomas can be challenging to diagnose,particularly when they present with atypical features that mimic other conditions,such as gastrointestinal stromal tumors(GISTs).This case highlights the diagnostic difficulties encountered when imaging subepithelial lesions,especially when conventional methods such as computed tomography(CT)and endoscopic ultrasound(EUS)are used.CASE SUMMARY A 44-year-old woman presented with intermittent abdominal distension and heartburn for three months.Her medical history included iron deficiency anemia,menorrhagia,and previous cholecystectomy.One week prior to admission,an endoscopy suggested a bulging gastric fundus,which was likely a GIST,along with chronic nonatrophic gastritis and bile reflux.CT and EUS revealed nodules in the gastric fundus,which were initially considered benign tumors with a differential diagnosis of stromal tumor or leiomyoma.During surgery,unexpected lesions were found in the liver pressing against the gastric fundus,leading to laparoscopic liver resection.Postoperative pathology confirmed the diagnosis of hepatic cavernous hemangiomas.The patient recovered well and was discharged five days later,with normal follow-up results at three months.CONCLUSION This case underscores the challenges in the preoperative diagnosis of GISTs,particularly the limitations of the use of CT and EUS for the evaluation of subepithelial lesions.While CT is the primary tool for visualizing abdominal tumors,it is difficult to detect smaller lesions and assess the layers of the gastrointestinal wall on CT.EUS is recommended for the evaluation of nodules smaller than 2 cm and is useful for distinguishing GISTs from other lesions;however,its accuracy with regard to the differential diagnosis is relatively low.In this case,the gastric distension observed on imaging led to the compression of a liver tumor against the stomach,resulting in the misinterpretation of the tumor as a gastric wall lesion. 展开更多
关键词 Hepatic hemangioma Gastrointestinal stromal tumors Left lobe tumor Subepithelial lesions Extragastric lesions Case report
下载PDF
Synchronization Characterization of DC Microgrid Converter Output Voltage and Improved Adaptive Synchronization Control Methods
9
作者 Wei Chen Xin Gao +2 位作者 Zhanhong Wei Xusheng Yang Zhao Li 《Energy Engineering》 2025年第2期805-821,共17页
This paper deeply introduces a brand-new research method for the synchronous characteristics of DC microgrid bus voltage and an improved synchronous control strategy.This method mainly targets the problem of bus volta... This paper deeply introduces a brand-new research method for the synchronous characteristics of DC microgrid bus voltage and an improved synchronous control strategy.This method mainly targets the problem of bus voltage oscillation caused by the bifurcation behavior of DC microgrid converters.Firstly,the article elaborately establishes a mathematical model of a single distributed power source with hierarchical control.On this basis,a smallworld network model that can better adapt to the topology structure of DC microgrids is further constructed.Then,a voltage synchronization analysis method based on the main stability function is proposed,and the synchronous characteristics of DC bus voltage are deeply studied by analyzing the size of the minimum non-zero eigenvalue.In view of the situation that the line coupling strength between distributed power sources is insufficient to achieve bus voltage synchronization,this paper innovatively proposes a new improved adaptive controller to effectively control voltage synchronization.And the convergence of the designed controller is strictly proved by using Lyapunov’s stability theorem.Finally,the effectiveness and feasibility of the designed controller in this paper are fully verified through detailed simulation experiments.After comparative analysis with the traditional adaptive controller,it is found that the newly designed controller can make the bus voltages of each distributed power source achieve synchronization more quickly,and is significantly superior to the traditional adaptive controller in terms of anti-interference performance. 展开更多
关键词 DC microgrid BIFURCATION small-world network voltage synchronization improved adaptive control
下载PDF
Dynamic Variation of Vegetation NPP and Its Driving Forces in the Yellow River Basin, China
10
作者 WANG Shimei MA Yutao +1 位作者 GONG Jie JIN Tiantian 《Chinese Geographical Science》 2025年第1期24-37,共14页
The productivity of vegetation is influenced by both climate change and human activities.Understanding the specific contributions of these influencing factors is crucial for ecological conservation and regional sustai... The productivity of vegetation is influenced by both climate change and human activities.Understanding the specific contributions of these influencing factors is crucial for ecological conservation and regional sustainability.This study utilized a combination of multi-source data to examine the spatiotemporal patterns of Net Primary Productivity(NPP)in the Yellow River Basin(YRB),China from 1982 to 2020.Additionally,a scenario-based approach was employed to compare Potential NPP(PNPP)with Actual NPP(ANPP)to determine the relative roles of climatic and human factors in NPP changes.The PNPP was estimated using the Lund-Potsdam-Jena General Ecosystem Simulator(LPJ-GUESS)model,while ANPP was evaluated by the Carnegie-Ames-Stanford Approach(CASA)model using different NDVI data sources.Both model simulations revealed that significant greening occurring in the YRB,with a gradual decrease observed from southeast to northwest.According to the LPJ_GUESS model simulations,areas experiencing an increasing trend in NPP accounted for 86.82% of the YRB.When using GIMMS and MODIS NDVI data with CASA model simulations,areas showing an increasing trend in NPP accounted for 71.42% and 97.02%,respectively.Furthermore,both climatic conditions and human factors had positive effects on vegetation restoration;approximated 41.15% of restored vegetation areas were influenced by both climate variation and human activities,while around 31.93% were solely affected by climate variation.However,it was found that human activities served as the principal driving force of vegetation degradation within the YRB,impacting 26.35% of degraded areas solely due to human activities.Therefore,effective management strategies encompassing both human activities and climate change adaptation are imperative for facilitating vegetation restoration within this region.These findings will valuable for enhancing our understanding in NPP changes and its underlying factors,thereby contributing to improved ecological management and the pursuit of regional carbon neutrality in China. 展开更多
关键词 Net Primary Productivity(NPP) vegetation greening Carnegie-Ames-Stanford Approach(CASA) Lund-Potsdam-Jena General Ecosystem Simulator(LPJ_GUESS) Yellow River Basin(YRB) China
下载PDF
Land use/cover change and ecological network in Gansu Province,China during 2000-2020 and their simulations in 2050
11
作者 MA Xinshu XIN Cunlin +6 位作者 CHEN Ning XIN Shunjie CHEN Hongxiang ZHANG Bo KANG Ligang WANG Yu JIAO Jirong 《Journal of Arid Land》 2025年第1期43-57,共15页
Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and t... Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making. 展开更多
关键词 patch-generating land use simulation(PLUS)model morphological spatial pattern analysis(MSPA) circuit theory ecological source ecological resistance surface ecological corridor ecological pinch point
下载PDF
An improved GCN−TCN−AR model for PM_(2.5) predictions in the arid areas of Xinjiang,China
12
作者 CHEN Wenqian BAI Xuesong +1 位作者 ZHANG Na CAO Xiaoyi 《Journal of Arid Land》 2025年第1期93-111,共19页
As one of the main characteristics of atmospheric pollutants,PM_(2.5) severely affects human health and has received widespread attention in recent years.How to predict the variations of PM_(2.5) concentrations with h... As one of the main characteristics of atmospheric pollutants,PM_(2.5) severely affects human health and has received widespread attention in recent years.How to predict the variations of PM_(2.5) concentrations with high accuracy is an important topic.The PM_(2.5) monitoring stations in Xinjiang Uygur Autonomous Region,China,are unevenly distributed,which makes it challenging to conduct comprehensive analyses and predictions.Therefore,this study primarily addresses the limitations mentioned above and the poor generalization ability of PM_(2.5) concentration prediction models across different monitoring stations.We chose the northern slope of the Tianshan Mountains as the study area and took the January−December in 2019 as the research period.On the basis of data from 21 PM_(2.5) monitoring stations as well as meteorological data(temperature,instantaneous wind speed,and pressure),we developed an improved model,namely GCN−TCN−AR(where GCN is the graph convolution network,TCN is the temporal convolutional network,and AR is the autoregression),for predicting PM_(2.5) concentrations on the northern slope of the Tianshan Mountains.The GCN−TCN−AR model is composed of an improved GCN model,a TCN model,and an AR model.The results revealed that the R2 values predicted by the GCN−TCN−AR model at the four monitoring stations(Urumqi,Wujiaqu,Shihezi,and Changji)were 0.93,0.91,0.93,and 0.92,respectively,and the RMSE(root mean square error)values were 6.85,7.52,7.01,and 7.28μg/m^(3),respectively.The performance of the GCN−TCN−AR model was also compared with the currently neural network models,including the GCN−TCN,GCN,TCN,Support Vector Regression(SVR),and AR.The GCN−TCN−AR outperformed the other current neural network models,with high prediction accuracy and good stability,making it especially suitable for the predictions of PM_(2.5)concentrations.This study revealed the significant spatiotemporal variations of PM_(2.5)concentrations.First,the PM_(2.5) concentrations exhibited clear seasonal fluctuations,with higher levels typically observed in winter and differences presented between months.Second,the spatial distribution analysis revealed that cities such as Urumqi and Wujiaqu have high PM_(2.5) concentrations,with a noticeable geographical clustering of pollutions.Understanding the variations in PM_(2.5) concentrations is highly important for the sustainable development of ecological environment in arid areas. 展开更多
关键词 air pollution PM_(2.5) concentrations graph convolution network(GCN)model temporal convolutional network(TCN)model autoregression(AR)model northern slope of the Tianshan Mountains
下载PDF
Multi-Scenario Probabilistic Load Flow Calculation Considering Wind Speed Correlation
13
作者 Xueqian Wang Hongsheng Su 《Energy Engineering》 2025年第2期667-680,共14页
As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wi... As the proportion of newenergy increases,the traditional cumulant method(CM)produces significant errorswhen performing probabilistic load flow(PLF)calculations with large-scale wind power integrated.Considering the wind speed correlation,a multi-scenario PLF calculation method that combines random sampling and segmented discrete wind farm power was proposed.Firstly,based on constructing discrete scenes of wind farms,the Nataf transform is used to handle the correlation between wind speeds.Then,the random sampling method determines the output probability of discrete wind power scenarios when wind speed exhibits correlation.Finally,the PLF calculation results of each scenario areweighted and superimposed following the total probability formula to obtain the final power flow calculation result.Verified in the IEEE standard node system,the absolute percent error(APE)for the mean and standard deviation(SD)of the node voltages and branch active power are all within 1%,and the average root mean square(AMSR)values of the probability curves are all less than 1%. 展开更多
关键词 Wind speed correlation probabilistic load flow multi-scenario PIECEWISE cumulant method
下载PDF
The third dimension of alpine plant leaf traits is related to cold-tolerance
14
作者 Yuan Wang Ji Suonan +4 位作者 Kun Liu Yanni Gao Sihao Zhu Qian Liu Ning Zhao 《Plant Diversity》 2025年第1期159-165,共7页
Alpine plants possess unique traits to adapt alpine environments.Whether leaf trait relationships of alpine plants can be captured by the two trait dimensions of organ size and resource economics is unknown.We hypothe... Alpine plants possess unique traits to adapt alpine environments.Whether leaf trait relationships of alpine plants can be captured by the two trait dimensions of organ size and resource economics is unknown.We hypothesized that,beyond the trait dimensions of leaf size and resource economics,nonstructured carbohydrates(NSC)would reflect a dimension of cold-tolerance in alpine plants.To test this hypothesis,we measured 12 leaf traits critical to leaf construction and growth in 143 species across 7 sites ranging from alpine steppes to alpine meadows along an environmental gradient on the Tibetan Plateau.Furthermore,a cold resistance experiment was conducted at one of these sites to estimate the lethal temperature causing 50%frost damage(LT_(50))of 11 alpine species.The majority of variations in 12 leaf traits of alpine plants were captured by three trait axes,in which leaf carbon(LCC)and NSC(including leaf starch;LSC and leaf soluble sugars;LSS)were clustered in a new dimension(PC3)beyond leaf size and structure,and resource economics.Although LCC,LSC and LSS all showed negative correlations with mean annual temperature,a significant negative correlation was only found between LSS and LT_(50).It indicated that PC3 was able to reflect the cold-tolerance of alpine plants to some extent,in which LSS was the most critical trait.The storage and transformation of NSC under stressful conditions could reflect a dimension of long-term metabolic adaptation and cold-tolerance,which is an extension of the resource-utilization strategy beyond construction cost and growth. 展开更多
关键词 Non-structured carbohydrates Resource economics Stress resistance Trait relationships The lethal temperature causing 50%frost damage(LT50)
下载PDF
Herders'willingness to accept compensation for grassland grazing ban in Northwest China
15
作者 Huifang Liu Lingling Hou +2 位作者 Zhibiao Nan Jikun Huang Liufang Su 《Journal of Integrative Agriculture》 2025年第1期366-379,共14页
Payment for Ecosystem Services(PES)has been widely acknowledged as an effective tool for mitigating grassland degradation and enhancing ecosystem services provision.However,critical factors,such as herders'willing... Payment for Ecosystem Services(PES)has been widely acknowledged as an effective tool for mitigating grassland degradation and enhancing ecosystem services provision.However,critical factors,such as herders'willingness to accept(WTA)preferences and compensation expectations,are often overlooked,leading to insufficient effectiveness of PES initiatives.This study focused on grassland ecological compensation policy(GECP),quantifying herders'WTA compensation for grassland grazing bans.Through face-to-face surveys and employing the contingent valuation method,we estimated households'WTA for participating in a grassland conservation program to bolster ecosystem service provision.Our findings indicated that herders required an average compensation of 237 CNY mu^(-1)yr^(-1)to engage in the grazing ban program.Notably,herders'environmental awareness positively influenced their willingness to participate,whereas larger family sizes were negatively correlated with WTA.Additionally,herders in better health,with higher livestock incomes or categorized as semi-herders,tended to accept lower compensation levels.These insights are crucial for improving the effectiveness of GECP and provide valuable reference points for similar analyses in economically disadvantaged and ecologically fragile regions. 展开更多
关键词 anchoring effect conditional value method double-bounded dichotomous choice model ecosystem services grassland system willingness to accept
下载PDF
Deciphering Water Oxidation Catalysts:The Dominant Role of Surface Chemistry over Reconstruction Degree in Activity Promotion
16
作者 Li An Jianyi Li +7 位作者 Yuanmiao Sun Jiamin Zhu Justin Zhu Yeow Seow Hong Zhang Nan Zhang Pinxian Xi Zhichuan J.Xu Chun‑Hua Yan 《Nano-Micro Letters》 SCIE EI CAS 2025年第3期340-354,共15页
Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has ... Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation. 展开更多
关键词 Oxygen evolution reaction Perovskite oxides DOPING Activation and reconstruction
下载PDF
Investigation of a NO_(x) emission from coal power plants in Texas, United States and its impact on the environment
17
作者 Mikalai Filonchyk Michael P.Peterson 《China Geology》 2025年第1期107-116,共10页
Texas is the largest state by area in the US after Alaska,and one of the top states in the production and consumption of electricity with many coal-fired plants.Coal-fired power plants emit greater than 70% of polluta... Texas is the largest state by area in the US after Alaska,and one of the top states in the production and consumption of electricity with many coal-fired plants.Coal-fired power plants emit greater than 70% of pollutants in the energy sector.When coal is burned to produce electricity,nitrogen oxides(NO_(x))are released into the air,one of the main pollutants that threaten human health and lead to a large number of premature deaths.The key to effective air quality management is the strict compliance of all plants with emission standards.However,not all Texas coal plants have the environmental equipment to lower pollutant emissions.Nitrogen dioxide(NO2)observations from the TROPOspheric Monitoring Instrument(TROPOMI)were used to evaluate the emissions for Texas power plants.Data from both the Emissions and Generation Resource Integrated Database(EGRID)and the Emissions Database for Global Atmospheric Research(EDGAR)were used to examine emissions.It was found that NOx emissions for Texas power plants range from 1.53 kt/year to 10.99 kt/year,with the Martin Lake,Limestone and Fayette Power Project stations being the top emitters.WA Parish and Martin Lake stations have the strongest NOx fluxes,with both exhibiting significant seasonal variability.Comparisons of bottom-up inventories for EDGAR and EGRID show a high correlation(r=0.956)and a low root mean square error(0.766).A more reasonable control policy would lead to much reduced NOx emissions. 展开更多
关键词 NO_(x)emission Enironmental pollution Power plants TROPOMI EDGAR Human health EGRID. Texas
下载PDF
Pancreatic primitive neuroectodermal tumors:Clinical features,treatment,and influencing factors
18
作者 Yan-Fei He Huan-Zhi Wang +4 位作者 Xiao-Dong Hu Jun-Qiang Liu Hu-Ming Li Jie Wang Shuang-Feng Lu 《World Journal of Gastrointestinal Oncology》 2025年第2期230-245,共16页
BACKGROUND Data on clinical characteristics,treatment outcomes,and prognosis of pancreatic primitive neuroectodermal tumors(PNETs)are limited.AIM To analyze the clinical data of 30 patients with pancreatic PNETs to id... BACKGROUND Data on clinical characteristics,treatment outcomes,and prognosis of pancreatic primitive neuroectodermal tumors(PNETs)are limited.AIM To analyze the clinical data of 30 patients with pancreatic PNETs to identify their clinical characteristics and factors associated with prognosis.METHODS We used the keywords"primary neuroectodermal tumor,""digestive tract,""pancreas,""pancreatic,"and"gastrointestinal,"individually or in combination,to collect data from a global database for all patients with pancreatic PNET to date.Univariate and Cox regression analyses were performed to identify prognostic factors for patient survival.RESULTS A total of 30 cases of pancreatic PNET were included in this study:15 males and 15 females with a mean age of 24 years.The main symptom was abdominal pain(73.3%),and the median tumor size was 7.85 cm.Twenty-four patients(80.0%)underwent surgery and nineteen patients received adjuvant therapy.Local metastasis was observed in 13 patients(43.3%),lymph node metastasis in 10 patients(33.3%),and distant metastasis in 6 patients(20.0%).Local recurrence was observed in 13 patients(43.3%).The median survival time of all patients was 29.4 months,and the overall estimated 1-year and 3-year survival rates were approximately 66.0%and 36.4%,respectively.Univariate analysis showed that chemotherapy(P=0.036),local metastasis(P=0.041),lymph node metastasis(P=0.003),distant metastasis(P=0.049),and surgical margins(P=0.048)were the prognostic factors affecting survival.Multivariate analysis revealed only lymph node metastasis(P=0.012)as a prognostic factor.CONCLUSION Pancreatic PNET is extremely rare,occurs in young adults,has no apparent sex predisposition,has a high rate of metastasis and early recurrence,and has a very poor prognosis.The diagnosis of pancreatic PNET requires a combination of clinical symptoms,pathologic features,immunohistochemistry,and cytogenetic analysis.Univariate analysis suggested that chemotherapy,metastasis,and surgical margins were prognostic factors affecting survival,and multivariate analysis suggested that lymph node metastasis is an important prognostic factor.Therefore,early diagnosis,early and extensive resection,and adjuvant chemoradiotherapy may help improve prognosis. 展开更多
关键词 Primitive neuroectodermal tumor PANCREAS SARCOMA DIAGNOSIS PROGNOSIS TREATMENT
下载PDF
Comparative study of a rabbit model of spinal tuberculosis using different concentrations of Mycobacterium tuberculosis
19
作者 Yong-Jie Qiao Xiao-Yang Song +3 位作者 Lv-Dan Zhang Feng Li Hao-Qiang Zhang Sheng-Hu Zhou 《World Journal of Orthopedics》 2025年第1期46-56,共11页
BACKGROUND Tuberculosis is among the most devastating infectious diseases worldwide.Spinal tuberculosis is not easy to detect at an early stage,which without effective treatment often leads to spinal deformity and spi... BACKGROUND Tuberculosis is among the most devastating infectious diseases worldwide.Spinal tuberculosis is not easy to detect at an early stage,which without effective treatment often leads to spinal deformity and spinal cord damage which in turn cause complications such as paraplegia and quadriplegia.In this study,we established a model using three concentrations of bacteria and carried out a comprehensive evaluation of the model by imaging,general observations,and histopathological and bacteriological studies.AIM To establish a rabbit model of spinal tuberculosis and examine the effect on the model’s efficacy using different concentrations of Mycobacterium tuberculosis(M.tuberculosis)inoculum.METHODS New Zealand rabbits were randomly divided into experimental,control and blank groups.The experimental and control animals were sensitized with complete Freund′s adjuvant,a hole was drilled beneath the upper endplate of the L6 vertebral body and filled with gelfoam sponge.The experimental group was divided into three subgroups(experimental 1,experimental 2,experimental 3)and infused with M.tuberculosis suspension at various concentrations.The control group was inoculated with saline and the blank group received no treatment.The 12-week post-operative survival rates were 100%,80%and 30%in the experimental groups inoculated with concentrations of 106,107 and 108 CFU/mL bacteria,respectively.RESULTS The survival rate of the control and blank groups was 100%.Vertebral body destruction at 8 weeks in the three experimental groups as determined by X-ray analysis was 33.3%,62.5%and 66.7%,and by computed tomography(CT)and 3-dimensional CT 44.4%,75%and 100%,respectively.At 12 weeks,the figures were 44.4%,75%and 100%by X-ray analysis and 44.4%,100%and 100%by CT and 3-dimensional CT,respectively.All surviving rabbits of the experimental groups had vertebral destruction.The positive bacterial culture rates were 22.2%,75%and 66.7%,respectively,in the experimental groups.After being sensitized with complete Freund's adjuvant,large differences were observed in the extent of spinal tuberculosis after inoculation of the rabbits with different concentrations of H37RV standard M.tuberculosis.CONCLUSION The experimental 1 had a low success rate at establishing an infection.The experimental 3 resulted in high mortality and complication rates.The experimental 2 was optimum for establishing a spinal tuberculosis model based on the high level of symptoms observed and the low rabbit mortality. 展开更多
关键词 Spinal tuberculosis Animal model H37RV Mycobacterium tuberculosis New Zealand rabbits
下载PDF
A review on global spatial distribution,sources and toxicity of perfluoroalkyl acid and prospect in the cryosphere
20
作者 LI Bowen Du Wentao +5 位作者 KANG Shichang CHEN Jizu JIANG Youyan YIN Lichen LU Changsheng LIU Hongyi 《Journal of Mountain Science》 2025年第1期167-183,共17页
Perfluoroalkyl acid analogs(PFAAs)are a class of chemically stable environmentally persistent organic pollutants(POPs)that are difficult to degrade and have a strong capacity to accumulate in the human body.PFAAs have... Perfluoroalkyl acid analogs(PFAAs)are a class of chemically stable environmentally persistent organic pollutants(POPs)that are difficult to degrade and have a strong capacity to accumulate in the human body.PFAAs have been found to be biotoxic to humans and have been detected in various environmental media,especially in the cryosphere at trace concentrations.The cryosphere,sensitively responds to climate change,plays a crucial role in the global water,carbon and energy cycles.However,researches on cryosphere PFAAs especially in Tibetan Plateau(TP)is limited.Therefore,we summarize the physicochemical properties,physiological toxicity,spatiotemporal distribution,sources,diffusion and migration pathways,as well as analysis and removal methods of PFAAs in the cryosphere regions.The results show that PFAAs pollutants are mainly produced and distributed in the more economically developed countries in Europe and the United States,as well as in East Asia,and PFAAs can be transported by atmospheric circulation and water cycle to remote regions including cryosphere regions.The current detection methods for PFAAs in cryosphere need to be further refined for increased accuracy and convenience.There is also a need to develop more effective removal methods that will reduce the environmental and human threats posed by these PFAAs.Finally,we propose key scientific questions for future research in cryosphere including PFAAs redistribution influenced by cryosphere changes,human activities,and the interaction of other spheres. 展开更多
关键词 Perfluoroalkyl acid CRYOSPHERE Physiological toxicity Analytical method Removal method
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部