The multi-source passive localization problem is a problem of great interest in signal pro-cessing with many applications.In this paper,a sparse representation model based on covariance matrix is constructed for the l...The multi-source passive localization problem is a problem of great interest in signal pro-cessing with many applications.In this paper,a sparse representation model based on covariance matrix is constructed for the long-range localization scenario,and a sparse Bayesian learning algo-rithm based on Laplace prior of signal covariance is developed for the base mismatch problem caused by target deviation from the initial point grid.An adaptive grid sparse Bayesian learning targets localization(AGSBL)algorithm is proposed.The AGSBL algorithm implements a covari-ance-based sparse signal reconstruction and grid adaptive localization dictionary learning.Simula-tion results show that the AGSBL algorithm outperforms the traditional compressed-aware localiza-tion algorithm for different signal-to-noise ratios and different number of targets in long-range scenes.展开更多
Objective:Cold regions exhibit a high prevalence of cardiovascular disease,particularly acute myocardial infarction(AMI),which is one of the leading causes of death associated with cardiovascular conditions.Cardiovasc...Objective:Cold regions exhibit a high prevalence of cardiovascular disease,particularly acute myocardial infarction(AMI),which is one of the leading causes of death associated with cardiovascular conditions.Cardiovascular disease is closely linked to the abnormal expression of long non-coding RNA(lncRNA).This study investigates whether circulating levels of lncRNA cardiac conduction regulatory RNA(CCRR)could serve as a biomarker for AMI.Materials and methods:We measured circulating CCRR from whole blood samples collected from 68 AMI patients and 69 non-AMI subjects.An AMI model was established using C57BL/6 mice.Quantitative reverse transcription PCR(qRT-PCR)was used to assess CCRR expression.Exosomes were isolated from cardiomyocytes,and their characteristics were evaluated using electron microscope and nanoparticle tracking analysis.The exosome inhibitor GW4869 was employed to examine the effect of exosomal CCRR on cardiac function using echocardiography.Protein expression was detected using Western blot and immunofluorescence staining.Results:The circulating level of CCRR was significantly higher in AMI patients(1.93±0.13)than in non-AMI subjects(1.00±0.05,P<0.001).The area under the ROC curve(AUC)of circulating CCRR was 0.821.Similar changes in circulating CCRR levels were consistently observed in an AMI mouse model.Exosomal CCRR derived from hypoxia-induced cardiomyocytes and cardiac tissue after AMI were increased,a change that was reversed by GW4869.Additionally,CCRR-overexpressing exosomes improved cardiac function in AMI.Conclusion:Circulating lncRNA CCRR is a potential predictor of AMI.Exosomal CCRR plays a role in the communication between the heart and other organs through circulation.展开更多
Forests are important ecosystems for economic and social development.However,the response of tree radial growth to climate has produced‘divergent problems'at high latitudes under global warming.In this study,the ...Forests are important ecosystems for economic and social development.However,the response of tree radial growth to climate has produced‘divergent problems'at high latitudes under global warming.In this study,the response stability and trend of Picea schrenkiana radial growth to variability in climate factors were analyzed in the mid-latitudes of the western Tien Shan Mountains.Radial growth of P.schrenkiana was mainly limited by minimum and mean temperatures.The divergent responses of radial growth occurred in response to the minimum and mean temperatures at the beginning of the growing season(April–May)of the current year,but responses to drought occurred in July–September of the previous year.And the mean and minimum temperatures in June–September of the current year were both stable.Radial growth first increased and then decreased according to the basal area increment,with a gradual increase in temperature.Therefore,forest ecosystems in mountainous arid areas will be increasingly affected by future climate warming.展开更多
CD93 and GAIP-interacting protein, C termius (GIPC) have been shown to interactively alter phagocytic processes of immune cells. CD93 and GIPC expression and localization during cen-tral nervous system inflammation ...CD93 and GAIP-interacting protein, C termius (GIPC) have been shown to interactively alter phagocytic processes of immune cells. CD93 and GIPC expression and localization during cen-tral nervous system inflammation have not yet been reported. In this study, we established a rat model of brain inlfammation by lipopolysaccharide injection to the lateral ventricle. In the brain of rats with inlfammation, western blots showed increased CD93 expression that decreased over time. GIPC expression was unaltered. Immunohistochemistry demonstrated extensive distribution of CD93 expression mainly in cell membranes in the cerebral cortex. After lipopoly-saccharide stimulation, CD93 expression increased and then reduced, with distinct staining in the cytoplasm and nucleus. Double immunolfuorescence staining in cerebral cortex of normal rats showed that CD93 and GIPC widely expressed in resting microglia and neurons. CD93 was mainly expressed in microglial and neuronal cell membranes, while GIPC was expressed in both cell membrane and cytoplasm. In the cerebral cortex at 9 hours after model establishment, CD93-immunoreactive signal diminished in microglial membrane, with cytoplasmic transloca-tion and aggregation detected. GIPC localization was unaltered in neurons and microglia. These results are the ifrst to demonstrate CD93 participation in pathophysiological processes of central nervous system inlfammation.展开更多
Cloud-radiation interaction has a large impact on the Earth's weather and climate change, and clouds with different heights cause different radiative forcing. Thus, the information on the statistics of cloud height a...Cloud-radiation interaction has a large impact on the Earth's weather and climate change, and clouds with different heights cause different radiative forcing. Thus, the information on the statistics of cloud height and its variation in space and time is very important to global climate change studies. In this paper, cloud top height (CTH), cloud base height (CBH) and cloud thickness over regions of the Tibetan Plateau, south slope of the plateau and South Asian Monsoon are analyzed based on CloudSat data during the period from June 2006 to December 2007. The results show that frequency of CTH and CBH in unit area over the studied regions have certain temporal-spatial continuity. The CTH and CBH of different cloud types have different variation scopes, and their seasonal variations are distinct. Cloud thickness is large (small) in summer (winter), and the percentages of different cloud types also have certain regularity.展开更多
The delay-causing text data contain valuable information such as the specific reasons for the delay,location and time of the disturbance,which can provide an efficient support for the prediction of train delays and im...The delay-causing text data contain valuable information such as the specific reasons for the delay,location and time of the disturbance,which can provide an efficient support for the prediction of train delays and improve the guidance of train control efficiency.Based on the train operation data and delay-causing data of the Wuhan-Guangzhou high-speed railway,the relevant algorithms in the natural language processing field are used to process the delay-causing text data.It also integrates the train operatingenvironment information and delay-causing text information so as to develop a cause-based train delay propagation prediction model.The Word2vec model is first used to vectorize the delay-causing text description after word segmentation.The mean model or the term frequency-inverse document frequency-weighted model is then used to generate the delay-causing sentence vector based on the original word vector.Afterward,the train operating-environment features and delay-causing sentence vector are input into the extreme gradient boosting(XGBoost)regression algorithm to develop a delay propagation prediction model.In this work,4 text feature processing methods and 8 regression algorithms are considered.The results demonstrate that the XGBoost regression algorithm has the highest prediction accuracy using the test features processed by the continuous bag of words and the mean models.Compared with the prediction model that only considers the train-operating-environment features,the results show that the prediction accuracy of the model is significantly improved with multi-ple regression algorithms after integrating the delay-causing feature.展开更多
The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric pro...The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric processes, tracing vapor sources, and reflect- ing the local weather and climate conditions. The composition and distribution of stable isotopes in precipitation in China are summarized and the factors that influence isotope ratios are elucidated. An overview of related research progress in China during the past several decades is presented and the prospects for future work in this subject area are described.展开更多
Train timetables and operations are defined by the train running time in sections,dwell time at stations,and headways between trains.Accurate estimation of these factors is essential to decision-making for train delay...Train timetables and operations are defined by the train running time in sections,dwell time at stations,and headways between trains.Accurate estimation of these factors is essential to decision-making for train delay reduction,train dispatching,and station capacity estimation.In the present study,we aim to propose a train dwell time model based on an averaging mechanism and dynamic updating to address the challenges in the train dwell time prediction problem(e.g.,dynamics over time,heavy-tailed distribution of data,and spatiotemporal relationships of factors)for real-time train dispatching.The averaging mechanism in the present study is based on multiple state-of-the-art base predictors,enabling the proposed model to integrate the advantages of the base predictors in addressing the challenges in terms of data attributes and data distributions.Then,considering the influence of passenger flow on train dwell time,we use a dynamic updating method based on exponential smoothing to improve the performance of the proposed method by considering the real-time passenger amount fluctuations(e.g.,passenger soars in peak hours or passenger plunges during regular periods).We conduct experiments with the train operation data and passenger flow data from the Chinese high-speed railway line.The results show that due to the advantages over the base predictors,the averaging mechanism can more accurately predict the dwell time at stations than its counterparts for different prediction horizons regarding predictive errors and variances.Further,the experimental results show that dynamic smoothing can significantly improve the accuracy of the proposed model during passenger amount changes,i.e.,15.4%and 15.5%corresponding to the mean absolute error and root mean square error,respectively.Based on the proposed predictor,a feature importance analysis shows that the planned dwell time and arrival delay are the two most important factors to dwell time.However,planned time has positive influences,whereas arrival delay has negative influences.展开更多
Fretting wear is a phenomenon,in which wear happens between two oscillatory moving contact surfaces in microscale amplitude.In this paper,the effect of debris between pad and specimen is analyzed by using a semi-concu...Fretting wear is a phenomenon,in which wear happens between two oscillatory moving contact surfaces in microscale amplitude.In this paper,the effect of debris between pad and specimen is analyzed by using a semi-concurrent multiscale method.Firstly,the macroscale fretting wear model is performed.Secondly,the part with the wear profile is imported from the macroscale model to a microscale model after running in stage.Thirdly,an effective pad’s radius is extracted by analyzing the contact pressure in order to take into account the effect of the debris.Finally,the effective radius is up-scaled from the microscale model to the macroscale model,which is used after running in stage.In this way,the effect of debris is considered by changing the radius of the pad in the macroscale model.Due to the smaller number of elements in the microscale model compared with the macroscale model containing the debris layer,the semi-concurrent method proposed in this paper is more computationally efficient.Moreover,the results of this semi-concurrent method show a better agreement with experimental data,compared to the results of the model ignoring the effect of debris.展开更多
Aerosol samples were collected at altitudes from 584 m a.s.l.to 3,804 m a.s.l.at seven sites of the eastern Tianshan.The occurrence,distribution,and possible sources of 47 trace metals—including alkali metals and alk...Aerosol samples were collected at altitudes from 584 m a.s.l.to 3,804 m a.s.l.at seven sites of the eastern Tianshan.The occurrence,distribution,and possible sources of 47 trace metals—including alkali metals and alkali earth metals,transition metals,lanthanoids,and heavy metals—were investigated.It was found that four sampling sites(Shuinichang,1,691 m a.s.l.;Urumqi City,809 m a.s.l.;Fu Kang Station,584 m a.s.l.;and Bogeda Glacier No.4,3,613 m a.s.l.)were contaminated mainly by heavy metals.Other three high-altitude sites(Urumqi Glacier No.1,3,804 m a.s.l.;Wang Feng road-maintenance station,3,039 m a.s.l.;and Tianshan Glaciology Station,2,135 m a.s.l.)were not polluted.The aerosol particles were clustered into two dominant types:crust-originated particles and pollution-derived particles.Aerosols from UG1,WF,and TGS were characterized by crust-originated particles such as clay,plagioclase,dolomite,alkali feldspar,and biotite;while those from SNC,Urumqi,FK,and BG4 were characterized by high content of Cl-rich particles,S-rich particles,and soot.The backward-trajectories results indicated that air masses arriving at SNC,Urumqi,FK,and BG4 were identified as the more polluted source,when compared to the short-range air mass transport from the North to UGI and WF.Relatively lower altitude,as well as terrain blocking,might be another important reason for the gradient difference in pollution influence among these seven places in the Urumqi River Basin.展开更多
The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies.Their use is important for arid areas where the precipitation events are limited,and bel...The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies.Their use is important for arid areas where the precipitation events are limited,and below-cloud evaporation is strong.This study presents the spatial and temporal characteristics of water vapor isotopologue across the Tianshan Mountains in arid central Asia using the NASAAura Tropospheric Emission Spectrometer(TES).The near-surface water vapor stable isotopes are enriched in summer and depleted in winter,consistent with the seasonality of precipitation isotopes.From the surface to 200 hPa,the isotope values in water vapor show a decreasing trend as the atmospheric pressure decreases and elevation rises.The vapor isotope values in the lower atmosphere in the southern basin of the Tianshan Mountains are usually higher than that in the northern basin,and the seasonal difference in vapor isotopes is slightly more significant in the southern basin.In addition,bottom vapor isotopologue in summer shows a depletion trend from west to east,consistent with the rainout effect of the westerly moisture path in central Asia.The isotopic signature provided by the TES is helpful to understand the moisture transport and below-cloud processes influencing stable water isotopes in meteoric water.展开更多
Aerosol samples were collected in the Shiyi Glacier, Qilian Mountains from July 24 to August 19, 2012 and analyzed for major water-soluble ionic species(F-, Cl-, NO2-, NO3-, SO42-, Na+, NH4+, K+, Mg2+and Ca2+) by ion ...Aerosol samples were collected in the Shiyi Glacier, Qilian Mountains from July 24 to August 19, 2012 and analyzed for major water-soluble ionic species(F-, Cl-, NO2-, NO3-, SO42-, Na+, NH4+, K+, Mg2+and Ca2+) by ion chromatography. SO42-and NH4+were the most abundant components of all the anions and cations, with average concentrations of 94.72 and 54.26 neq/m3, respectively, accounting for 34% and 20% of the total water-soluble ions analyzed. These mean ion concentrations were generally comparable with the background conditions in remote sites of the Qilian Mountains, but were much lower than those in certain cities in China. The particles were grouped into two dominant types according to their morphology and EDX signal: Si-rich particles and Fe-rich particles. Backward air mass trajectory analysis suggested that inland cities may contribute some anthropogenic pollution to this glacier, while the arid and semi-arid regions of central Asia were the primary sources of the mineral particles.展开更多
[Objectives]To explore the extraction conditions of essential oil from eucalyptus leaves.[Methods]The essential oil of eucalyptus leaves was extracted by steam distillation,and the yields of essential oil from eucalyp...[Objectives]To explore the extraction conditions of essential oil from eucalyptus leaves.[Methods]The essential oil of eucalyptus leaves was extracted by steam distillation,and the yields of essential oil from eucalyptus leaves under different extraction times,soaking times and different solid-liquid ratios were analyzed through orthogonal test with three factors and three variables.[Results]The effects of various factors on extraction results were:distillation time>solid-liquid ratio>soaking time.When the extraction time and soaking time were 1.5 and 2 h,and the solid-liquid ratio of eucalyptus leaves to distilled water was 1:10,the yield of essential oil was the highest(0.8%).The yield of essential oil increased with the increase of extraction and soaking time,but when reaching the optimal value,the yield decreased with the extension of time.Increasing the solid-liquid ratio can improve the yield of essential oil,but beyond a certain value the yield increased gradually while the cost performance decreased.[Conclusions]The results will provide some reference for the recovery and utilization of eucalyptus leaves.展开更多
This paper uses the component-based technology and the object oriented simulation technology to analyze the UUV navigation and control integration simulation system. We divide the system into components based on its s...This paper uses the component-based technology and the object oriented simulation technology to analyze the UUV navigation and control integration simulation system. We divide the system into components based on its structure, and describe every component using active diagram. By using the component-based technology, the system described here is easier to extended and be reused. At last, it realizes the whole UUV integrated navigation simulation course using the system to validate the availability.展开更多
Cardiac conduction regulatory RNA(CCRR)has been documented as an antiarrhythmic lncRNA in our earlier investigation.This study aimed to evaluate the effects of CCRR on SERCA2a and the associated Ca^(2+)homeostasis in ...Cardiac conduction regulatory RNA(CCRR)has been documented as an antiarrhythmic lncRNA in our earlier investigation.This study aimed to evaluate the effects of CCRR on SERCA2a and the associated Ca^(2+)homeostasis in myocardial infarction(MI).Overexpression of CCRR via AAV9-mediated delivery not only partially reversed ischemia-induced contractile dysfunction but also alleviated abnormal Ca^(2+)homeostasis and reduced the heightened methylation level of SERCA2a following MI.These effects were also observed in CCRR overexpressing transgenic mice.A conserved sequence domain of CCRR mimicked the protective function observed with the full length.Furthermore,silencing CCRR in healthy mice led to intracellular Ca^(2+)overloading of cardiomyocytes.CCRR increased SERCA2a protein stability by upregulating FTO expression.The direct interaction between CCRR and FTO protein was characterized by RNA-binding protein immunoprecipitation(RIP)analysis and RNA pulldown experiments.Activation of NFATc3 was identified as an upstream mechanism responsible for CCRR downregulation in MI.This study demonstrates that CCRR is a protective lncRNA that acts by maintaining the function of FTO,thereby reducing the m^(6)A RNA methylation level of SERCA2a,ultimately preserving calcium homeostasis for myocardial contractile function in MI.Therefore,CCRR may be considered a promising therapeutic strategy with a beneficial role in cardiac pathology.展开更多
Exciton behavior is crucial to the exploitation of light-emitting conjugated polymer(LCPs)for optoelectronic devices.Singlet excitons are easily trapped by the intrinsically defect structures.Herein,we set a polyfluor...Exciton behavior is crucial to the exploitation of light-emitting conjugated polymer(LCPs)for optoelectronic devices.Singlet excitons are easily trapped by the intrinsically defect structures.Herein,we set a polyfluorenol(PPFOH)as an example to systematically investigate its photophysical behavior to check the role of defect structures in LCPs.According to time-resolved photoluminescence analysis,the feature emission peaks from individual chain of PPFOH in diluted DMF solution is effectively avoided the influence of fluorenone formation,but the residual green-band emission at 550nm is easily observed in the PL spectra of PPFOH dilute toluene solution obtained delay 1.5 ns,confirmed the formation of“guest”physical aggregation-induced defect structure.Remarkably,efficient and ultrafast energy transfer from individual chain to defect structure is observed in PPFOH films.Interestingly,the efficient energy transfer happened for the film obtained from DMF solution(200 ps)than those of toluene ones(600 ps).Meanwhile,compared to relatively stable green-band emission in PPFOH film from toluene solution,red-shifted emission peak(11 nm)of PPFOH film from DMF solutions exposed to saturated DNT vapor also confirmed their different aggregation-induced green-band emission.Therefore,this aggregation defect structures are influenced on the photophysical property of LCPs in solid states.展开更多
An in situ high-energy X-ray diffraction(HE-XRD) technique was mainly used to investigate the micromechanical behavior of medium-Mn Fe-0.12 C-10.16 Mn-1.87 Al(in wt%) transformation-induced plasticit(TRIP) steel subje...An in situ high-energy X-ray diffraction(HE-XRD) technique was mainly used to investigate the micromechanical behavior of medium-Mn Fe-0.12 C-10.16 Mn-1.87 Al(in wt%) transformation-induced plasticit(TRIP) steel subjected to intercritical annealing at 625℃, 650℃, 675℃ and 700℃ for 1 h. As the intercritical annealing temperature increased, the volume fraction of retained austenite(RA) and ultimate tensilstress(UTS) increased, while the Lüders strain and yield stress(YS) decreased. The incremental workhardening exponent of experimental steel increased with increasing intercritical annealing temperatureThe overall trend of the transformation kinetics of the RA with respect to the true strain followed thsigmoidal shape predicted by the Olson and Cohen(OC) model. Load partitioning occurred among the ferrite, austenite and martensite immediately after entering the yielding stage. Because the stability of thRA decreased with increasing intercritical annealing temperature, the load undertaken by the martensitincreased. The moderate transformation kinetics of the RA and effective load partitioning among constituent phases were found to contribute to a favorable combination of strength and ductility for thimedium-Mn TRIP steel.展开更多
Both wear and fatigue occur in fretting condition,and they interact with one another during the whole process.Fretting fatigue is commonly analysed without considering the effect of wear in partial slip regime,althoug...Both wear and fatigue occur in fretting condition,and they interact with one another during the whole process.Fretting fatigue is commonly analysed without considering the effect of wear in partial slip regime,although wear affects the lifetime of crack initiation.This paper investigates,for the first time,the effect of wear debris on fretting fatigue crack initiation.To investigate the effect of debris,first fretting wear characteristics in partial slip regime are analysed for loading conditions.Then,the effect of wear on fretting fatigue crack initiation is investigated using Ruiz parameters and critical plane methods without considering the debris effect.Through the results,we can see that loading conditions affect the wear profiles in different ways.Moreover,wear has a significant effect on the fatigue in partial slip regime without considering debris especially on the crack initiation location.Finally,considering wear debris in the analysis,its effect on critical plane parameters is investigated.It is found that by considering the wear debris effect,the frtting fatigue crack initiation location is shifted towards the trailing edge.The predictions of both crack initiation location and lifetime show a good agreement with the experimental data.展开更多
文摘The multi-source passive localization problem is a problem of great interest in signal pro-cessing with many applications.In this paper,a sparse representation model based on covariance matrix is constructed for the long-range localization scenario,and a sparse Bayesian learning algo-rithm based on Laplace prior of signal covariance is developed for the base mismatch problem caused by target deviation from the initial point grid.An adaptive grid sparse Bayesian learning targets localization(AGSBL)algorithm is proposed.The AGSBL algorithm implements a covari-ance-based sparse signal reconstruction and grid adaptive localization dictionary learning.Simula-tion results show that the AGSBL algorithm outperforms the traditional compressed-aware localiza-tion algorithm for different signal-to-noise ratios and different number of targets in long-range scenes.
基金supported by grants from the Natural Science Foundation of China(81970202,81903609)by Natural Science Foundation of Heilongjiang Province,China(LH2022H002)+1 种基金by the Outstanding Young Talent Research Fund of College of Pharmacy,Harbin Medical University(2019-JQ-02)2021(the second batch)Research Funds for affiliated research institutes in Heilongjiang Province(CZKYF2021-2-C013).
文摘Objective:Cold regions exhibit a high prevalence of cardiovascular disease,particularly acute myocardial infarction(AMI),which is one of the leading causes of death associated with cardiovascular conditions.Cardiovascular disease is closely linked to the abnormal expression of long non-coding RNA(lncRNA).This study investigates whether circulating levels of lncRNA cardiac conduction regulatory RNA(CCRR)could serve as a biomarker for AMI.Materials and methods:We measured circulating CCRR from whole blood samples collected from 68 AMI patients and 69 non-AMI subjects.An AMI model was established using C57BL/6 mice.Quantitative reverse transcription PCR(qRT-PCR)was used to assess CCRR expression.Exosomes were isolated from cardiomyocytes,and their characteristics were evaluated using electron microscope and nanoparticle tracking analysis.The exosome inhibitor GW4869 was employed to examine the effect of exosomal CCRR on cardiac function using echocardiography.Protein expression was detected using Western blot and immunofluorescence staining.Results:The circulating level of CCRR was significantly higher in AMI patients(1.93±0.13)than in non-AMI subjects(1.00±0.05,P<0.001).The area under the ROC curve(AUC)of circulating CCRR was 0.821.Similar changes in circulating CCRR levels were consistently observed in an AMI mouse model.Exosomal CCRR derived from hypoxia-induced cardiomyocytes and cardiac tissue after AMI were increased,a change that was reversed by GW4869.Additionally,CCRR-overexpressing exosomes improved cardiac function in AMI.Conclusion:Circulating lncRNA CCRR is a potential predictor of AMI.Exosomal CCRR plays a role in the communication between the heart and other organs through circulation.
基金supported by the National Natural Science Foundation of China(Projects Nos.41861006 and 41630750)the Scientific Research Program of Higher Education Institutions of Gansu Province(2018C-02)the Research Ability Promotion Program for Young Teachers of Northwest Normal University(NWNU-LKQN2019-4)。
文摘Forests are important ecosystems for economic and social development.However,the response of tree radial growth to climate has produced‘divergent problems'at high latitudes under global warming.In this study,the response stability and trend of Picea schrenkiana radial growth to variability in climate factors were analyzed in the mid-latitudes of the western Tien Shan Mountains.Radial growth of P.schrenkiana was mainly limited by minimum and mean temperatures.The divergent responses of radial growth occurred in response to the minimum and mean temperatures at the beginning of the growing season(April–May)of the current year,but responses to drought occurred in July–September of the previous year.And the mean and minimum temperatures in June–September of the current year were both stable.Radial growth first increased and then decreased according to the basal area increment,with a gradual increase in temperature.Therefore,forest ecosystems in mountainous arid areas will be increasingly affected by future climate warming.
基金supported by the National Natural Science Foundation of China,No.31170766the Nantong Municipal Social Undertakings Technological Innovation and Demonstration Project Foundation,No.HS2012032the Natural Science Pre-research Project Foundation of Nantong University in 2012,No.12ZY020
文摘CD93 and GAIP-interacting protein, C termius (GIPC) have been shown to interactively alter phagocytic processes of immune cells. CD93 and GIPC expression and localization during cen-tral nervous system inflammation have not yet been reported. In this study, we established a rat model of brain inlfammation by lipopolysaccharide injection to the lateral ventricle. In the brain of rats with inlfammation, western blots showed increased CD93 expression that decreased over time. GIPC expression was unaltered. Immunohistochemistry demonstrated extensive distribution of CD93 expression mainly in cell membranes in the cerebral cortex. After lipopoly-saccharide stimulation, CD93 expression increased and then reduced, with distinct staining in the cytoplasm and nucleus. Double immunolfuorescence staining in cerebral cortex of normal rats showed that CD93 and GIPC widely expressed in resting microglia and neurons. CD93 was mainly expressed in microglial and neuronal cell membranes, while GIPC was expressed in both cell membrane and cytoplasm. In the cerebral cortex at 9 hours after model establishment, CD93-immunoreactive signal diminished in microglial membrane, with cytoplasmic transloca-tion and aggregation detected. GIPC localization was unaltered in neurons and microglia. These results are the ifrst to demonstrate CD93 participation in pathophysiological processes of central nervous system inlfammation.
基金funded by National Natural Science Foundation of China(40830102 and 41205016)
文摘Cloud-radiation interaction has a large impact on the Earth's weather and climate change, and clouds with different heights cause different radiative forcing. Thus, the information on the statistics of cloud height and its variation in space and time is very important to global climate change studies. In this paper, cloud top height (CTH), cloud base height (CBH) and cloud thickness over regions of the Tibetan Plateau, south slope of the plateau and South Asian Monsoon are analyzed based on CloudSat data during the period from June 2006 to December 2007. The results show that frequency of CTH and CBH in unit area over the studied regions have certain temporal-spatial continuity. The CTH and CBH of different cloud types have different variation scopes, and their seasonal variations are distinct. Cloud thickness is large (small) in summer (winter), and the percentages of different cloud types also have certain regularity.
基金This work was supported by the National Nature Science Foundation of China(Nos.71871188 and U1834209)the Research and development project of China National Railway Group Co.,Ltd(No.P2020X016).
文摘The delay-causing text data contain valuable information such as the specific reasons for the delay,location and time of the disturbance,which can provide an efficient support for the prediction of train delays and improve the guidance of train control efficiency.Based on the train operation data and delay-causing data of the Wuhan-Guangzhou high-speed railway,the relevant algorithms in the natural language processing field are used to process the delay-causing text data.It also integrates the train operatingenvironment information and delay-causing text information so as to develop a cause-based train delay propagation prediction model.The Word2vec model is first used to vectorize the delay-causing text description after word segmentation.The mean model or the term frequency-inverse document frequency-weighted model is then used to generate the delay-causing sentence vector based on the original word vector.Afterward,the train operating-environment features and delay-causing sentence vector are input into the extreme gradient boosting(XGBoost)regression algorithm to develop a delay propagation prediction model.In this work,4 text feature processing methods and 8 regression algorithms are considered.The results demonstrate that the XGBoost regression algorithm has the highest prediction accuracy using the test features processed by the continuous bag of words and the mean models.Compared with the prediction model that only considers the train-operating-environment features,the results show that the prediction accuracy of the model is significantly improved with multi-ple regression algorithms after integrating the delay-causing feature.
基金supported by the National Natural Science Foundation of China (No. 41161012)the Program for New Century Excellent Talents in University by the Education Ministry of China (No. NCET-10-0019)
文摘The isotope ratios in precipitation are associated with various meteorological processes and display obvious spatial and temporal distributions, and thus can be used as impo~_nt techniques in inversing atmospheric processes, tracing vapor sources, and reflect- ing the local weather and climate conditions. The composition and distribution of stable isotopes in precipitation in China are summarized and the factors that influence isotope ratios are elucidated. An overview of related research progress in China during the past several decades is presented and the prospects for future work in this subject area are described.
基金This work was supported by the National Natural Science Foundation of China(No.71871188).
文摘Train timetables and operations are defined by the train running time in sections,dwell time at stations,and headways between trains.Accurate estimation of these factors is essential to decision-making for train delay reduction,train dispatching,and station capacity estimation.In the present study,we aim to propose a train dwell time model based on an averaging mechanism and dynamic updating to address the challenges in the train dwell time prediction problem(e.g.,dynamics over time,heavy-tailed distribution of data,and spatiotemporal relationships of factors)for real-time train dispatching.The averaging mechanism in the present study is based on multiple state-of-the-art base predictors,enabling the proposed model to integrate the advantages of the base predictors in addressing the challenges in terms of data attributes and data distributions.Then,considering the influence of passenger flow on train dwell time,we use a dynamic updating method based on exponential smoothing to improve the performance of the proposed method by considering the real-time passenger amount fluctuations(e.g.,passenger soars in peak hours or passenger plunges during regular periods).We conduct experiments with the train operation data and passenger flow data from the Chinese high-speed railway line.The results show that due to the advantages over the base predictors,the averaging mechanism can more accurately predict the dwell time at stations than its counterparts for different prediction horizons regarding predictive errors and variances.Further,the experimental results show that dynamic smoothing can significantly improve the accuracy of the proposed model during passenger amount changes,i.e.,15.4%and 15.5%corresponding to the mean absolute error and root mean square error,respectively.Based on the proposed predictor,a feature importance analysis shows that the planned dwell time and arrival delay are the two most important factors to dwell time.However,planned time has positive influences,whereas arrival delay has negative influences.
文摘Fretting wear is a phenomenon,in which wear happens between two oscillatory moving contact surfaces in microscale amplitude.In this paper,the effect of debris between pad and specimen is analyzed by using a semi-concurrent multiscale method.Firstly,the macroscale fretting wear model is performed.Secondly,the part with the wear profile is imported from the macroscale model to a microscale model after running in stage.Thirdly,an effective pad’s radius is extracted by analyzing the contact pressure in order to take into account the effect of the debris.Finally,the effective radius is up-scaled from the microscale model to the macroscale model,which is used after running in stage.In this way,the effect of debris is considered by changing the radius of the pad in the macroscale model.Due to the smaller number of elements in the microscale model compared with the macroscale model containing the debris layer,the semi-concurrent method proposed in this paper is more computationally efficient.Moreover,the results of this semi-concurrent method show a better agreement with experimental data,compared to the results of the model ignoring the effect of debris.
基金supported by the National Natural Science Foundation of China (41201065 41121001, 41261017, 41171057, 41161012)the Funds for Creative Research Groups of China (41121001)+3 种基金the foundation for Excellent Youth Scholars of CAREERI, CAS (51Y251B51)the SKLCS foundation (Grant No. SKLCSZZ-2012-01-01)the National Basic Research Program of China (2010CB951003, 2010CB951404)the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-EW-311)
文摘Aerosol samples were collected at altitudes from 584 m a.s.l.to 3,804 m a.s.l.at seven sites of the eastern Tianshan.The occurrence,distribution,and possible sources of 47 trace metals—including alkali metals and alkali earth metals,transition metals,lanthanoids,and heavy metals—were investigated.It was found that four sampling sites(Shuinichang,1,691 m a.s.l.;Urumqi City,809 m a.s.l.;Fu Kang Station,584 m a.s.l.;and Bogeda Glacier No.4,3,613 m a.s.l.)were contaminated mainly by heavy metals.Other three high-altitude sites(Urumqi Glacier No.1,3,804 m a.s.l.;Wang Feng road-maintenance station,3,039 m a.s.l.;and Tianshan Glaciology Station,2,135 m a.s.l.)were not polluted.The aerosol particles were clustered into two dominant types:crust-originated particles and pollution-derived particles.Aerosols from UG1,WF,and TGS were characterized by crust-originated particles such as clay,plagioclase,dolomite,alkali feldspar,and biotite;while those from SNC,Urumqi,FK,and BG4 were characterized by high content of Cl-rich particles,S-rich particles,and soot.The backward-trajectories results indicated that air masses arriving at SNC,Urumqi,FK,and BG4 were identified as the more polluted source,when compared to the short-range air mass transport from the North to UGI and WF.Relatively lower altitude,as well as terrain blocking,might be another important reason for the gradient difference in pollution influence among these seven places in the Urumqi River Basin.
基金This research was supported by the National Natural Science Foundation of China(Nos.41971034 and 41701028)the Foundation for Distinguished Young Scholars of Gansu Province(No.20JR10RA112)the Northwest Normal University(No.NWNU LKZD2021-04)。
文摘The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies.Their use is important for arid areas where the precipitation events are limited,and below-cloud evaporation is strong.This study presents the spatial and temporal characteristics of water vapor isotopologue across the Tianshan Mountains in arid central Asia using the NASAAura Tropospheric Emission Spectrometer(TES).The near-surface water vapor stable isotopes are enriched in summer and depleted in winter,consistent with the seasonality of precipitation isotopes.From the surface to 200 hPa,the isotope values in water vapor show a decreasing trend as the atmospheric pressure decreases and elevation rises.The vapor isotope values in the lower atmosphere in the southern basin of the Tianshan Mountains are usually higher than that in the northern basin,and the seasonal difference in vapor isotopes is slightly more significant in the southern basin.In addition,bottom vapor isotopologue in summer shows a depletion trend from west to east,consistent with the rainout effect of the westerly moisture path in central Asia.The isotopic signature provided by the TES is helpful to understand the moisture transport and below-cloud processes influencing stable water isotopes in meteoric water.
基金supported by the National Natural Science Foundation of China (Nos. 41201065, 41121001, 41261017, 41171057, 41161012)Funds for Creative Research Groups of China (No. 41121001)+3 种基金the Foundation for Excellent Youth Scholars of CAREERI, CAS (No. 51Y251B51)the SKLCS Foundation (No. SKLCSZZ-2012-01-01)the National Basic Research Program of China (Nos. 2010CB951003, 2010CB951404)the Knowledge Innovation Project of the Chinese Academy of Sciences (No. KZCX2-EW-311)
文摘Aerosol samples were collected in the Shiyi Glacier, Qilian Mountains from July 24 to August 19, 2012 and analyzed for major water-soluble ionic species(F-, Cl-, NO2-, NO3-, SO42-, Na+, NH4+, K+, Mg2+and Ca2+) by ion chromatography. SO42-and NH4+were the most abundant components of all the anions and cations, with average concentrations of 94.72 and 54.26 neq/m3, respectively, accounting for 34% and 20% of the total water-soluble ions analyzed. These mean ion concentrations were generally comparable with the background conditions in remote sites of the Qilian Mountains, but were much lower than those in certain cities in China. The particles were grouped into two dominant types according to their morphology and EDX signal: Si-rich particles and Fe-rich particles. Backward air mass trajectory analysis suggested that inland cities may contribute some anthropogenic pollution to this glacier, while the arid and semi-arid regions of central Asia were the primary sources of the mineral particles.
基金Supported by Doctoral Start-up Fund of Guangxi Minzu Normal University(2021 BS003).
文摘[Objectives]To explore the extraction conditions of essential oil from eucalyptus leaves.[Methods]The essential oil of eucalyptus leaves was extracted by steam distillation,and the yields of essential oil from eucalyptus leaves under different extraction times,soaking times and different solid-liquid ratios were analyzed through orthogonal test with three factors and three variables.[Results]The effects of various factors on extraction results were:distillation time>solid-liquid ratio>soaking time.When the extraction time and soaking time were 1.5 and 2 h,and the solid-liquid ratio of eucalyptus leaves to distilled water was 1:10,the yield of essential oil was the highest(0.8%).The yield of essential oil increased with the increase of extraction and soaking time,but when reaching the optimal value,the yield decreased with the extension of time.Increasing the solid-liquid ratio can improve the yield of essential oil,but beyond a certain value the yield increased gradually while the cost performance decreased.[Conclusions]The results will provide some reference for the recovery and utilization of eucalyptus leaves.
文摘This paper uses the component-based technology and the object oriented simulation technology to analyze the UUV navigation and control integration simulation system. We divide the system into components based on its structure, and describe every component using active diagram. By using the component-based technology, the system described here is easier to extended and be reused. At last, it realizes the whole UUV integrated navigation simulation course using the system to validate the availability.
基金supported by the National Natural Science Foundation of China(81970202,81903609,U21A20339)the Natural Science Foundation of Heilongjiang Province,China(LH2022H002)+1 种基金the Outstanding Young Talent Research Fund of College of Pharmacy,Harbin Medical University(2019-JQ-02)2021(the second batch)Research Funds for affiliated research institutes in Heilongjiang Province(CZKYF2021-2-C013).
文摘Cardiac conduction regulatory RNA(CCRR)has been documented as an antiarrhythmic lncRNA in our earlier investigation.This study aimed to evaluate the effects of CCRR on SERCA2a and the associated Ca^(2+)homeostasis in myocardial infarction(MI).Overexpression of CCRR via AAV9-mediated delivery not only partially reversed ischemia-induced contractile dysfunction but also alleviated abnormal Ca^(2+)homeostasis and reduced the heightened methylation level of SERCA2a following MI.These effects were also observed in CCRR overexpressing transgenic mice.A conserved sequence domain of CCRR mimicked the protective function observed with the full length.Furthermore,silencing CCRR in healthy mice led to intracellular Ca^(2+)overloading of cardiomyocytes.CCRR increased SERCA2a protein stability by upregulating FTO expression.The direct interaction between CCRR and FTO protein was characterized by RNA-binding protein immunoprecipitation(RIP)analysis and RNA pulldown experiments.Activation of NFATc3 was identified as an upstream mechanism responsible for CCRR downregulation in MI.This study demonstrates that CCRR is a protective lncRNA that acts by maintaining the function of FTO,thereby reducing the m^(6)A RNA methylation level of SERCA2a,ultimately preserving calcium homeostasis for myocardial contractile function in MI.Therefore,CCRR may be considered a promising therapeutic strategy with a beneficial role in cardiac pathology.
基金the National Natural Science Foundation of China(Nos.22105099,61874053)Natural Science Foundation of Jiangsu Province(No.BK20200700)the open research fund from Anhui Province Key Laboratory of Optoelectronic Materials Science and Technology(No.OMST202101).
文摘Exciton behavior is crucial to the exploitation of light-emitting conjugated polymer(LCPs)for optoelectronic devices.Singlet excitons are easily trapped by the intrinsically defect structures.Herein,we set a polyfluorenol(PPFOH)as an example to systematically investigate its photophysical behavior to check the role of defect structures in LCPs.According to time-resolved photoluminescence analysis,the feature emission peaks from individual chain of PPFOH in diluted DMF solution is effectively avoided the influence of fluorenone formation,but the residual green-band emission at 550nm is easily observed in the PL spectra of PPFOH dilute toluene solution obtained delay 1.5 ns,confirmed the formation of“guest”physical aggregation-induced defect structure.Remarkably,efficient and ultrafast energy transfer from individual chain to defect structure is observed in PPFOH films.Interestingly,the efficient energy transfer happened for the film obtained from DMF solution(200 ps)than those of toluene ones(600 ps).Meanwhile,compared to relatively stable green-band emission in PPFOH film from toluene solution,red-shifted emission peak(11 nm)of PPFOH film from DMF solutions exposed to saturated DNT vapor also confirmed their different aggregation-induced green-band emission.Therefore,this aggregation defect structures are influenced on the photophysical property of LCPs in solid states.
基金supported by the National Key Research and Development Program of China (No. 2017YFA0403804)the National Natural Science Foundation of China (NSFC) (Nos. 51471032 and 51527801)+3 种基金the Fundamental Research Funds for the Central Universities (Nos. 06111020 and 06111040)the State Key Laboratory for Advanced Metals and Materials (Nos. 2016Z-01, 2016Z-12, and 2016Z-19)financial support from the Chinese Scholarship Council (CSC)supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences (No. DE-AC02-06CH11357)
文摘An in situ high-energy X-ray diffraction(HE-XRD) technique was mainly used to investigate the micromechanical behavior of medium-Mn Fe-0.12 C-10.16 Mn-1.87 Al(in wt%) transformation-induced plasticit(TRIP) steel subjected to intercritical annealing at 625℃, 650℃, 675℃ and 700℃ for 1 h. As the intercritical annealing temperature increased, the volume fraction of retained austenite(RA) and ultimate tensilstress(UTS) increased, while the Lüders strain and yield stress(YS) decreased. The incremental workhardening exponent of experimental steel increased with increasing intercritical annealing temperatureThe overall trend of the transformation kinetics of the RA with respect to the true strain followed thsigmoidal shape predicted by the Olson and Cohen(OC) model. Load partitioning occurred among the ferrite, austenite and martensite immediately after entering the yielding stage. Because the stability of thRA decreased with increasing intercritical annealing temperature, the load undertaken by the martensitincreased. The moderate transformation kinetics of the RA and effective load partitioning among constituent phases were found to contribute to a favorable combination of strength and ductility for thimedium-Mn TRIP steel.
文摘Both wear and fatigue occur in fretting condition,and they interact with one another during the whole process.Fretting fatigue is commonly analysed without considering the effect of wear in partial slip regime,although wear affects the lifetime of crack initiation.This paper investigates,for the first time,the effect of wear debris on fretting fatigue crack initiation.To investigate the effect of debris,first fretting wear characteristics in partial slip regime are analysed for loading conditions.Then,the effect of wear on fretting fatigue crack initiation is investigated using Ruiz parameters and critical plane methods without considering the debris effect.Through the results,we can see that loading conditions affect the wear profiles in different ways.Moreover,wear has a significant effect on the fatigue in partial slip regime without considering debris especially on the crack initiation location.Finally,considering wear debris in the analysis,its effect on critical plane parameters is investigated.It is found that by considering the wear debris effect,the frtting fatigue crack initiation location is shifted towards the trailing edge.The predictions of both crack initiation location and lifetime show a good agreement with the experimental data.