Accurate nitrogen(N)nutrition diagnosis is essential for improving N use efficiency in crop production.The widely used critical N(Nc)dilution curve traditionally depends solely on agronomic variables,neglecting crop w...Accurate nitrogen(N)nutrition diagnosis is essential for improving N use efficiency in crop production.The widely used critical N(Nc)dilution curve traditionally depends solely on agronomic variables,neglecting crop water status.With three-year field experiments with winter wheat,encompassing two irrigation levels(rainfed and irrigation at jointing and anthesis)and three N levels(0,180,and 270 kg ha1),this study aims to establish a novel approach for determining the Nc dilution curve based on crop cumulative transpiration(T),providing a comprehensive analysis of the interaction between N and water availability.The Nc curves derived from both crop dry matter(DM)and T demonstrated N concentration dilution under different conditions with different parameters.The equation Nc=6.43T0.24 established a consistent relationship across varying irrigation regimes.Independent test results indicated that the nitrogen nutrition index(NNI),calculated from this curve,effectively identifies and quantifies the two sources of N deficiency:insufficient N supply in the soil and insufficient soil water concentration leading to decreased N availability for root absorption.Additionally,the NNI calculated from the Nc-DM and Nc-T curves exhibited a strong negative correlation with accumulated N deficit(Nand)and a positive correlation with relative grain yield(RGY).The NNI derived from the Nc-T curve outperformed the NNI derived from the Nc-DM curve concerning its relationship with Nand and RGY,as indicated by larger R2 values and smaller AIC.The novel Nc curve based on T serves as an effective diagnostic tool for assessing winter wheat N status,predicting grain yield,and optimizing N fertilizer management across varying irrigation conditions.These findings would provide new insights and methods to improve the simulations of water-N interaction relationship in crop growth models.展开更多
The vertically integrated emission rate,centroid altitude,peak emission rate,and peak height of the hydroxyl(OH)airglow were calculated from Thermosphere Ionosphere Mesosphere Energetics and Dynamics(TIMED)/Sounding o...The vertically integrated emission rate,centroid altitude,peak emission rate,and peak height of the hydroxyl(OH)airglow were calculated from Thermosphere Ionosphere Mesosphere Energetics and Dynamics(TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)observations to study the seasonal and interannual variations in the intensity and location of the OH emission.The emission rate is inversely proportional to the height of the emission,with the semiannual oscillation dominating at low latitudes and the annual oscillation dominating at higher latitudes.The OH emission is modulated by the quasibiennial oscillation at the equator,and the quasibiennial oscillation signal is weak at other latitudes.We represented the vertical transport of atomic oxygen by using atomic oxygen concentrations obtained from a global atmospheric model,the Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension simulations.Compared with the amplitudes of the migrating diurnal tide(DW1)calculated from temperature data observed by TIMED/SABER,we found that both the vertical transport of atomic oxygen and DW1 amplitudes in the equatorial region exhibit semiannual oscillation and quasibiennial oscillation,which have a strong correlation with the variations in the amplitude and phase of semiannual oscillation and quasibiennial oscillation in OH emission.It is likely that the DW1 affects the vertical transport of atomic oxygen that is involved in the reaction to produce O3,thus affecting the OH emission.We analyzed the relationship between OH emission and solar activity by using the solar radio flux at 10.7 cm as a proxy for solar activity.The results showed that the OH emission is well correlated with solar activity,and the modulation of OH emission by solar activity has a significant latitudinal variation.The small correlation between emission height and solar activity indicates that solar activity modulates OH emission mainly through chemical rather than dynamic processes.展开更多
The spatiotemporal extension/expansion of mine areas is affected by multiple factors.So far,very little has been done to examine the interaction between mine areas and political or economic realities.The(ultra‐)mafic...The spatiotemporal extension/expansion of mine areas is affected by multiple factors.So far,very little has been done to examine the interaction between mine areas and political or economic realities.The(ultra‐)mafic magmatic mines in China played a specific role in supporting national development and providing an ideal research subject for monitoring their interrelationship.In this study,remote sensing and mining‐related GIS data were used to identify and analyze 1233(ultra‐)mafic magmatic mine area polygons in China,which covered approximately 322.96 km2 of land and included a V–Ti–Fe mine,a copper–nickel mine,a chromite mine,an asbestos mine,and a diamond mine.It was found that(1)the areal expansion of mines is significantly related to the mine types,perimeter,topography,and population density.(2)The mine area variation also reflects market and policy realities.The temporal expansion of the mine area from 2010 to 2020 followed an S‐shaped pattern(with the turning point occurring in 2014),closely related to iron overcapacity and tightened mining policies.(3)The complexity(D)of the mine area may reflect mine design and excavation practices.To be specific,lower D indicates early‐stage or artisanal/small‐scale mining,whereas higher D represents large‐scale mining.This study demonstrates that the detailed mapping of mine land can serve as an indicator to implement miningrelated market and policy changes.The(ultra‐)mafic mines area data set can be accessed at https://zenodo.org/record/7636616#.Y-p0uXaZOa0.展开更多
Extreme heat stress events are becoming more frequent under anticipated climate change,which can have devastating impacts on rice growth and yield.To quantify the effects of short-term heat stress at booting stage on ...Extreme heat stress events are becoming more frequent under anticipated climate change,which can have devastating impacts on rice growth and yield.To quantify the effects of short-term heat stress at booting stage on nonstructural carbohydrates(NSC)remobilization in rice,two varieties(Nanjing 41 and Wuyunjing 24)were subjected to 32/22/27°C(maximum/minimum/mean),36/26/31°C,40/30/35°C,and 44/34/39°C for 2,4 and 6 days in phytotrons at booting stage during 2014 and 2015.Yield and yield components,dry matter partitioning index(DMPI),NSC accumulation and translocation were measured and calculated.The results showed that the increase of high-temperature level and duration significantly reduced grain yield by suppressing spikelet number per panicle,seed-setting rate,and grain weight.Heat stress at booting decreased DMPI in panicles,increased DMPI in stems,but had no significant effect on photosynthetic rate.Stem NSC concentration increased whereas panicles NSC concentration,stem NSC translocation efficiency,and contribution of stem NSC to grain yield decreased.Severe heat stress even transformed the stem into a carbohydrate sink during grain filling.The heat-tolerant Wuyunjing 24 showed a higher NSC transport capacity under heat stress than the heat-sensitive Nanjing 41.Heat degree-days(HDD),which combines the effects of the intensity and duration of heat stress,used for quantifying the impacts of heat stress indicates the threshold HDD for the termination of NSC translocation is 9.82°C day.Grain yield was negatively correlated with stem NSC concentration and accumulation at maturity,and yield reduction was tightly related to NSC translocation reduction.The results suggest that heat stress at booting inhibits NSC translocation due to sink size reduction.Therefore,genotypes with higher NSC transport capacity under heat stress could be beneficial for rice yield formation.展开更多
The principal pathology of Alzheimer＇s disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile pl aques, which in turn induce neuroinflammation in the brain. Triptolide, a ...The principal pathology of Alzheimer＇s disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile pl aques, which in turn induce neuroinflammation in the brain. Triptolide, a natural extract from the vine-like herb Tripterygium wilfordii Hook F, has potent anti-inflammatory and immunosuppressive efficacy. Therefore, we determined if triptolide can inhibit activation and proliferation of microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer＇s disease. We used 1 or 5 μg/kg/d triptolide to treat APP/PS1 double transgenic mice （aged 4-4.5 months） for 45 days. Unbiased stereology analysis found that triptolide dose-dependent- ly reduced the total number of microglial cells, and transformed microglial cells into the resting state. Further, triptolide （5 μg/kg/d） also reduced the total number of hippocampal astrocytes. Our in vivo test results indicate that triptolide suppresses activation and proliferation of microglial cells and astrocytes in the hippocampus of APP/PS 1 double transgenic mice with Alzheimer＇s disease.展开更多
Photocatalytic water purification is an efficient environmental protection method that can be used to eliminate toxic and harmful substances from industrial effluents.However,the TiO2-based catalysts currently in use ...Photocatalytic water purification is an efficient environmental protection method that can be used to eliminate toxic and harmful substances from industrial effluents.However,the TiO2-based catalysts currently in use absorb only a small portion of the solar spectrum in the ultraviolet(UV)region,resulting in lower efficiency.In this paper,we demonstrate a molybdenum disulfide/zeolitic imidazolate framework-8(MoS2/ZIF-8)composite photocatalyst that increases the photocatalytic degradation of ciprofloxacin(CIP)and tetracycline hydrochloride(TC)by factors of 1.21 and 1.07,respectively.The transformation products of CIP and TC from the catalysis processes are tentatively identified,with the metal-organic framework(MOF)being considered to be the main active species with holes being considered as the main active species.The hydrogen production rate of the MoS2/ZIF-8 nanocomposites is 1.79 times higher than that of MoS2.This work provides a novel perspective for exploring original and efficient 1T/2H-MoS2/MOF-based photocatalysts by optimizing the construction of surface nano-heterojunction structures.The composite photocatalyst is found to be durable,with its catalytic performance being preserved under stability testing.Thus,1T/2H-MoS2/MOF-based photocatalysts have excellent prospects for practical antibiotic-degradation engineering.展开更多
This study aimed to explore the mechanism of a novel mutation （p.Lys38Glu） in apolipoprotein H （APOH） gene causing hereditary beta2-glycoprotein I （β2GPI） deficiency and thrombosis in a proband with thrombophil...This study aimed to explore the mechanism of a novel mutation （p.Lys38Glu） in apolipoprotein H （APOH） gene causing hereditary beta2-glycoprotein I （β2GPI） deficiency and thrombosis in a proband with thrombophilia. The plasma level of β2GPI was measured by ELISA and Western blotting, and anti-β2GPI antibody by ELISA. Lupus anticoagulant （LA） was assayed using the dilute Russell viper venom time. Deficiency of the major natural anticoagulants including protein C （PC）, protein S （PS）, antithrombin （AT） and thrombomodulin （TM） was excluded from the proband. A mutation analysis was performed by amplification and sequencing of the APOH gene. Wild type and mutant （c.112A〉G） APOH expression plasmids were constructed and transfected into HEK293T cells. The results showed that the thrornbin generation capacity of the proband was higher than that of the other family members. Missense mutation p.Lys38Glu in APOH gene and LA coexisted in the proband. The mutation led to β2GPI deficiency and thrombosis by impairing the protein production and inhibiting the platelet aggregation. It was concluded that the recurrent thrombosis of the proband is associated with the coexistence ofp.Lys38Glu mutation in APOH gene and LA in plasma.展开更多
Background Data regarding the influence of weekends and Chinese national holiday＇s admission on the outcomes of patients with ST-elevated myocardial infarction （STEMI） is lacking. This study sought to investigate t...Background Data regarding the influence of weekends and Chinese national holiday＇s admission on the outcomes of patients with ST-elevated myocardial infarction （STEMI） is lacking. This study sought to investigate the effect of Chinese national holidays and weekend admission on outcomes in patients with STEMI undergoing primary percutaneous coronary intervention （PPCI）. Methods Patients pre- senting with STEMI within 12 h of symptom onset who underwent PPCI were retrospectively enrolled. The primary outcome of in-hospital mortality and major adverse cardiovascular events in patients presenting Chinese national holiday＇s and weekends versus weekdays was evaluated. Results A total of 441 STEMI patients were enrolled in this study. Of these, 129 （29.3%） patients were admitted during Chinese national holidays and weekends and 312 （70.7%） during weekdays. Patients admitted during holidays and weekends were more likely to present with Killip class Ⅲ-Ⅳ. Patients admitted during holidays and weekends experienced a significantly longer door-to-baUoon time, symptom onset-to-door time as well as symptom onset-to-balloon time. The in-hospital mortality between patients presenting holidays and weekends versus weekdays was comparable. However, patients admitted during holidays and weekends have a signitieantly higher rate of in-hospital major adverse cardiovascular events. Multivariate analysis demonstrated that holidays and weekends admission was independ- ently associated with adverse outcomes. Conclusions In China, STEMI patients undergoing PPCI during national holidays and weekends have worse in-hospital outcomes compared to those admitted during weekdays. These findings suggest that continuous efforts should be undertaken to enhance the Chinese healthcare system and to ensure that comparable outcomes are achieved for all STEMI patients regardless of time of presentation.展开更多
The particle morphology determined by the sintering process is the director factor affecting the electrochemical performance of Ni-rich NMC cathode materials.To prepare the ideal NMC particles,it is of great significa...The particle morphology determined by the sintering process is the director factor affecting the electrochemical performance of Ni-rich NMC cathode materials.To prepare the ideal NMC particles,it is of great significance to understand the morphological changes during sintering process.In this work,the morphology evolution of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)synthesis at temperature ranging from 300–1080℃were observed by in situ SEM.The uniform mixture of spherical Ni_(0.8)Mn_(0.1)Co_(0.1)(OH)_(2)precursor and lithium sources(LiOH)was employed by high temperature solid-state process inside the SEM,which enables us to observe morphology changes in real time.The results show that synthetic reaction of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)usually includes three processes:the raw materials’dehydration,oxidation,and combination,accompanied by a significant reduction in particle size,which is important reference to control the synthesis temperature.As heating temperature rise,the morphology of mixture also changed from flake to brick-shaped.However,Ni nanoparticle formation is apparent at higher temperature~1000℃,suggesting a structural transformation from a layered to a rock-salt-like structure.Combining the in-situ observed changes in size and morphology,and with the premise of ensuring the morphology change from flakes to bricks,reducing the sintering temperature as much as possible to prevent excessive reduction in particle size and layered to a rock-salt structure transformation is recommended for prepare ideal NMC particles.展开更多
Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissecte...Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.展开更多
Maximum frost heave of unsaturated frost-susceptible soils,in conjunction with a high water table,is an important consideration for the design of foundations in seasonally frozen regions.Therefore,it is necessary to e...Maximum frost heave of unsaturated frost-susceptible soils,in conjunction with a high water table,is an important consideration for the design of foundations in seasonally frozen regions.Therefore,it is necessary to evaluate accurately and efficiently the maximum frost heave for a given soil.For this purpose,a series of one-sided freezing experiments was conducted on unsaturated silty clay in an open system.Multistage cooling of sufficient duration was applied to the soil sample's top,while constant above-zero temperatures were maintained at the bottom.Then,a simple methodology for calculating maximum frost heave at a given cooling temperature was derived utilizing information obtained within the limited time allotted for each stage.On this basis,an empirical equation for defining maximum frost heave as a function of cooling temperature and overburden pressure was determined.Overall,this study provides a simple and practical procedure that is applicable to the evaluation of maximum frost heave of unsaturated frost-susceptible soils.展开更多
A gear fault detection analysis method based on Fractional Wavelet Transform(FRWT)and Back Propagation Neural Network(BPNN)is proposed.Taking the changing order as the variable,the optimal order of gear vibration sign...A gear fault detection analysis method based on Fractional Wavelet Transform(FRWT)and Back Propagation Neural Network(BPNN)is proposed.Taking the changing order as the variable,the optimal order of gear vibration signals is determined by discrete fractional Fourier transform.Under the optimal order,the fractional wavelet transform is applied to eliminate noise from gear vibration signals.In this way,useful components of vibration signals can be successfully separated from background noise.Then,a set of feature vectors obtained by calculating the characteristic parameters for the de-noised signals are used to characterize the gear vibration features.Finally,the feature vectors are divided into two groups,including training samples and testing samples,which are input into the BPNN for learning and classification.Experimental results showed that this gear fault detection analysis method could well maintain the useful signal components related to gear faults and effectively extract the weak fault feature.The accuracy rate reached 96.67%in the identification of the type of gear fault.展开更多
Electron beam(EB) degradation of perfluorooctanoic acid(PFOA) and perfluorooctane sulfonate(PFOS) in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics, ...Electron beam(EB) degradation of perfluorooctanoic acid(PFOA) and perfluorooctane sulfonate(PFOS) in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics, and degradation rates increased with increasing initial p H. Radical scavengers' experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS, especially hydrated electron. The decomposition efficiencies were 95.7% for PFOA and 85.9% for PFOS, by EB irradiation in an anoxic alkaline solution(p H = 13).The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH_2 unit were proposed.展开更多
Extreme high-temperature stress(HTS) associated with climate change poses potential threats to wheat grain yield and quality. Wheat grain protein concentration(GPC) is a determinant of wheat quality for human nutritio...Extreme high-temperature stress(HTS) associated with climate change poses potential threats to wheat grain yield and quality. Wheat grain protein concentration(GPC) is a determinant of wheat quality for human nutrition and is often neglected in attempts to assess climate change impacts on wheat production. Crop models are useful tools for quantification of temperature impacts on grain yield and quality.Current crop models either cannot simulate or can simulate only partially the effects of HTS on crop N dynamics and grain N accumulation. There is a paucity of observational data on crop N and grain quality collected under systematic HTS scenarios to develop algorithms for model improvement as well as evaluate crop models. Two-year phytotron experiments were conducted with two wheat cultivars under HTS at anthesis, grain filling, and both stages. HTS significantly reduced total aboveground N and increased the rate of grain N accumulation, while total aboveground N and the rate of grain N accumulation were more sensitive to HTS at anthesis than at grain filling. The observed relationships between total aboveground N, rate of grain N accumulation, and HTS were quantified and incorporated into the WheatGrow model. The new HTS routines improved simulation of the dynamics of total aboveground N, grain N accumulation, and GPC by the model. The improved model provided better estimates of total aboveground N, grain N accumulation, and GPC under HTS(the normalized root mean square error was reduced by 40%, 85%, and 80%, respectively) than the original WheatGrow model. The improvements in the model enhance its applicability to the assessment of climate change effects on wheat grain quality by reducing the uncertainties of simulating N dynamics and grain quality under HTS.展开更多
The(ultra-)mafic mine tailings pond revealed a weathering discrepancy in the tailings profile,which provided a valuable analog to assess the role of carbonate and silicate weathering of the basalt.In this study,drill-...The(ultra-)mafic mine tailings pond revealed a weathering discrepancy in the tailings profile,which provided a valuable analog to assess the role of carbonate and silicate weathering of the basalt.In this study,drill-cores samples were selected from the Wanniangou V–Ti–Fe mine tailings pond(Sichuan province,China)to investigate the mineralogicand geochemical characteristics in the tailings profile.The results reveal(1)the tailings pond profile consist of upper and lower layers.The upper layer is composed of carbonate weathering(1.4%),which was formed in the initial stages of tailings exposure and represented a minimal weathering degree.(2)The lower layer was primarily observed at the aquifer zone of the tailings pond,and was consistent with 0.45%carbonate weathering and 48.4%silicate weathering.(3)The weathering discrepancy in the tailings profile could be due to the sulfide oxidation and aerobic/flowing aquifer,which facilitate the water-tailings reactions.The tailings profile provides an analog to studying basalt weathering,as it spans both carbonate and silicate weathering.This research reinforces the idea that silicate weathering is predominant in basaltic areas and plays a crucial role in regulating atmospheric CO_(2)(carbon dioxide)levels on Earth.展开更多
BACKGROUND Littoral cell angioma(LCA)is a rare benign vascular tumor of the spleen.Given its rarity,standard diagnostic and therapeutic recommendations have yet to be developed for reported cases.Splenectomy is the on...BACKGROUND Littoral cell angioma(LCA)is a rare benign vascular tumor of the spleen.Given its rarity,standard diagnostic and therapeutic recommendations have yet to be developed for reported cases.Splenectomy is the only method of obtaining a pathological diagnosis and providing treatment to obtain a favorable prognosis.CASE SUMMARY A 33-year-old female presented with abdominal pain for one month.Computed tomography and ultrasound revealed splenomegaly with multiple lesions and two accessory spleens.The patient underwent laparoscopic total splenectomy and accessory splenectomy,and splenic LCA was confirmed by pathology.Four months after surgery,the patient presented with acute liver failure,was readmitted,rapidly progressed to multiple organ dysfunction syndrome and died.CONCLUSION Preoperative diagnosis of LCA is challenging.We systematically reviewed online databases to identify the relevant literature and found a close relationship between malignancy and immunodysregulation.When a patient suffers from both splenic tumors and malignancy or immune-related disease,LCA is possible.Due to potential malignancy,total splenectomy(including accessory spleen)and regular follow-up after surgery are recommended.If LCA is diagnosed after surgery,a comprehensive postoperative examination is needed.展开更多
Finite element simulations are increasingly providing a versatile environment for this topic. In this study, a two-dimensional finite element analysis is conducted to predict the deformation of high embankment in Bazh...Finite element simulations are increasingly providing a versatile environment for this topic. In this study, a two-dimensional finite element analysis is conducted to predict the deformation of high embankment in Bazhun heavy-haul railway, China. A recently developed nonlinear softening-type constitutive model is utilized to model the be- havior of subgrade filling materials subjected to freeze-thaw cycles. For the convenience of practical application, the dynamic loading induced by a vehicle is treated as a quasi-static axle load. The deformation of this embankment with different moisture content under freeze-thaw cycles is compared. The results show that when subjected to the first freeze-thaw cycle, the embankment experienced significant deformation variations. Maximum deformation was usually achieved after the embankment with optimum moisture content experienced six freeze-thaw cycles, however, the em- bankment with moisre content of 8.0% and 9.5% deforms continuously even after experiencing almost ten freeze-thaw cycles. Overall, this study provides a simple nonlinear finite element approach for calculating the deformation of the embankment in changing climate conditions.展开更多
基金supported by the National Key Research and Development Program of China(2022YFD2001005)the Key Research&Development Program of Jiangsu province(BE2021358)+2 种基金the National Natural Science Foundation of China(32271989)the Natural Science Foundation of Jiangsu province(BK20220146)the Jiangsu Independent Innovation Fund Project of Agricultural Science and Technology[CX(23)3121].
文摘Accurate nitrogen(N)nutrition diagnosis is essential for improving N use efficiency in crop production.The widely used critical N(Nc)dilution curve traditionally depends solely on agronomic variables,neglecting crop water status.With three-year field experiments with winter wheat,encompassing two irrigation levels(rainfed and irrigation at jointing and anthesis)and three N levels(0,180,and 270 kg ha1),this study aims to establish a novel approach for determining the Nc dilution curve based on crop cumulative transpiration(T),providing a comprehensive analysis of the interaction between N and water availability.The Nc curves derived from both crop dry matter(DM)and T demonstrated N concentration dilution under different conditions with different parameters.The equation Nc=6.43T0.24 established a consistent relationship across varying irrigation regimes.Independent test results indicated that the nitrogen nutrition index(NNI),calculated from this curve,effectively identifies and quantifies the two sources of N deficiency:insufficient N supply in the soil and insufficient soil water concentration leading to decreased N availability for root absorption.Additionally,the NNI calculated from the Nc-DM and Nc-T curves exhibited a strong negative correlation with accumulated N deficit(Nand)and a positive correlation with relative grain yield(RGY).The NNI derived from the Nc-T curve outperformed the NNI derived from the Nc-DM curve concerning its relationship with Nand and RGY,as indicated by larger R2 values and smaller AIC.The novel Nc curve based on T serves as an effective diagnostic tool for assessing winter wheat N status,predicting grain yield,and optimizing N fertilizer management across varying irrigation conditions.These findings would provide new insights and methods to improve the simulations of water-N interaction relationship in crop growth models.
基金the National Natural Science Foundation of China(Grant Numbers 42374195 and 42188101)a fellowship from the China National Postdoctoral Program for Innovative Talents(Grant Number BX20230273).
文摘The vertically integrated emission rate,centroid altitude,peak emission rate,and peak height of the hydroxyl(OH)airglow were calculated from Thermosphere Ionosphere Mesosphere Energetics and Dynamics(TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)observations to study the seasonal and interannual variations in the intensity and location of the OH emission.The emission rate is inversely proportional to the height of the emission,with the semiannual oscillation dominating at low latitudes and the annual oscillation dominating at higher latitudes.The OH emission is modulated by the quasibiennial oscillation at the equator,and the quasibiennial oscillation signal is weak at other latitudes.We represented the vertical transport of atomic oxygen by using atomic oxygen concentrations obtained from a global atmospheric model,the Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension simulations.Compared with the amplitudes of the migrating diurnal tide(DW1)calculated from temperature data observed by TIMED/SABER,we found that both the vertical transport of atomic oxygen and DW1 amplitudes in the equatorial region exhibit semiannual oscillation and quasibiennial oscillation,which have a strong correlation with the variations in the amplitude and phase of semiannual oscillation and quasibiennial oscillation in OH emission.It is likely that the DW1 affects the vertical transport of atomic oxygen that is involved in the reaction to produce O3,thus affecting the OH emission.We analyzed the relationship between OH emission and solar activity by using the solar radio flux at 10.7 cm as a proxy for solar activity.The results showed that the OH emission is well correlated with solar activity,and the modulation of OH emission by solar activity has a significant latitudinal variation.The small correlation between emission height and solar activity indicates that solar activity modulates OH emission mainly through chemical rather than dynamic processes.
文摘The spatiotemporal extension/expansion of mine areas is affected by multiple factors.So far,very little has been done to examine the interaction between mine areas and political or economic realities.The(ultra‐)mafic magmatic mines in China played a specific role in supporting national development and providing an ideal research subject for monitoring their interrelationship.In this study,remote sensing and mining‐related GIS data were used to identify and analyze 1233(ultra‐)mafic magmatic mine area polygons in China,which covered approximately 322.96 km2 of land and included a V–Ti–Fe mine,a copper–nickel mine,a chromite mine,an asbestos mine,and a diamond mine.It was found that(1)the areal expansion of mines is significantly related to the mine types,perimeter,topography,and population density.(2)The mine area variation also reflects market and policy realities.The temporal expansion of the mine area from 2010 to 2020 followed an S‐shaped pattern(with the turning point occurring in 2014),closely related to iron overcapacity and tightened mining policies.(3)The complexity(D)of the mine area may reflect mine design and excavation practices.To be specific,lower D indicates early‐stage or artisanal/small‐scale mining,whereas higher D represents large‐scale mining.This study demonstrates that the detailed mapping of mine land can serve as an indicator to implement miningrelated market and policy changes.The(ultra‐)mafic mines area data set can be accessed at https://zenodo.org/record/7636616#.Y-p0uXaZOa0.
基金the National Key Research and Development Program of China(2016YFD0300110)the National Natural Science Foundation of China(31571566)+1 种基金the National Science Fund for Distinguished Young Scholars(31725020)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).We would like to thank Arielle Biro at Yale University for her assistance with English language and grammatical editing.
文摘Extreme heat stress events are becoming more frequent under anticipated climate change,which can have devastating impacts on rice growth and yield.To quantify the effects of short-term heat stress at booting stage on nonstructural carbohydrates(NSC)remobilization in rice,two varieties(Nanjing 41 and Wuyunjing 24)were subjected to 32/22/27°C(maximum/minimum/mean),36/26/31°C,40/30/35°C,and 44/34/39°C for 2,4 and 6 days in phytotrons at booting stage during 2014 and 2015.Yield and yield components,dry matter partitioning index(DMPI),NSC accumulation and translocation were measured and calculated.The results showed that the increase of high-temperature level and duration significantly reduced grain yield by suppressing spikelet number per panicle,seed-setting rate,and grain weight.Heat stress at booting decreased DMPI in panicles,increased DMPI in stems,but had no significant effect on photosynthetic rate.Stem NSC concentration increased whereas panicles NSC concentration,stem NSC translocation efficiency,and contribution of stem NSC to grain yield decreased.Severe heat stress even transformed the stem into a carbohydrate sink during grain filling.The heat-tolerant Wuyunjing 24 showed a higher NSC transport capacity under heat stress than the heat-sensitive Nanjing 41.Heat degree-days(HDD),which combines the effects of the intensity and duration of heat stress,used for quantifying the impacts of heat stress indicates the threshold HDD for the termination of NSC translocation is 9.82°C day.Grain yield was negatively correlated with stem NSC concentration and accumulation at maturity,and yield reduction was tightly related to NSC translocation reduction.The results suggest that heat stress at booting inhibits NSC translocation due to sink size reduction.Therefore,genotypes with higher NSC transport capacity under heat stress could be beneficial for rice yield formation.
基金supported by China Postdoctoral Science Foundation,No.2016M590757the Postdoctoral Science Foundation of Xiangya Hospital of Central South University of China,No.20+4 种基金the Hunan Provincial Natural Science Foundation of China,No.2015JJ6010a grant from the Basic Research Program of Science and Technology Commission Foundation of Hunan Province of China,No.2015JC3059the Project Fund of the Department of Education in Hunan Province of China,No.15A023,13C1107the Scientific Research Project Fund of Health Department of Hunan Province of China,No.B2011-071,B2016096a grant from the Construction Program of the Key Discipline in Hunan Province of China
文摘The principal pathology of Alzheimer＇s disease includes neuronal extracellular deposition of amyloid-beta peptides and formation of senile pl aques, which in turn induce neuroinflammation in the brain. Triptolide, a natural extract from the vine-like herb Tripterygium wilfordii Hook F, has potent anti-inflammatory and immunosuppressive efficacy. Therefore, we determined if triptolide can inhibit activation and proliferation of microglial cells and astrocytes in the APP/PS1 double transgenic mouse model of Alzheimer＇s disease. We used 1 or 5 μg/kg/d triptolide to treat APP/PS1 double transgenic mice （aged 4-4.5 months） for 45 days. Unbiased stereology analysis found that triptolide dose-dependent- ly reduced the total number of microglial cells, and transformed microglial cells into the resting state. Further, triptolide （5 μg/kg/d） also reduced the total number of hippocampal astrocytes. Our in vivo test results indicate that triptolide suppresses activation and proliferation of microglial cells and astrocytes in the hippocampus of APP/PS 1 double transgenic mice with Alzheimer＇s disease.
基金Dr.Wen-Qian Chen and Miss Lin-Yue Li contributed equally to this work.The authors of this work gratefully acknowledge the financial support provided by the National Natural Science Foundation of China(41573096 and 21707064)the Program for Changjiang Scholars and Innovative Research Teams in University(IRT_17R71)the State Environmental Protection Key Laboratory of Integrated Surface Water–Groundwater Pollution Control,Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control(2017B030301012).
文摘Photocatalytic water purification is an efficient environmental protection method that can be used to eliminate toxic and harmful substances from industrial effluents.However,the TiO2-based catalysts currently in use absorb only a small portion of the solar spectrum in the ultraviolet(UV)region,resulting in lower efficiency.In this paper,we demonstrate a molybdenum disulfide/zeolitic imidazolate framework-8(MoS2/ZIF-8)composite photocatalyst that increases the photocatalytic degradation of ciprofloxacin(CIP)and tetracycline hydrochloride(TC)by factors of 1.21 and 1.07,respectively.The transformation products of CIP and TC from the catalysis processes are tentatively identified,with the metal-organic framework(MOF)being considered to be the main active species with holes being considered as the main active species.The hydrogen production rate of the MoS2/ZIF-8 nanocomposites is 1.79 times higher than that of MoS2.This work provides a novel perspective for exploring original and efficient 1T/2H-MoS2/MOF-based photocatalysts by optimizing the construction of surface nano-heterojunction structures.The composite photocatalyst is found to be durable,with its catalytic performance being preserved under stability testing.Thus,1T/2H-MoS2/MOF-based photocatalysts have excellent prospects for practical antibiotic-degradation engineering.
文摘This study aimed to explore the mechanism of a novel mutation （p.Lys38Glu） in apolipoprotein H （APOH） gene causing hereditary beta2-glycoprotein I （β2GPI） deficiency and thrombosis in a proband with thrombophilia. The plasma level of β2GPI was measured by ELISA and Western blotting, and anti-β2GPI antibody by ELISA. Lupus anticoagulant （LA） was assayed using the dilute Russell viper venom time. Deficiency of the major natural anticoagulants including protein C （PC）, protein S （PS）, antithrombin （AT） and thrombomodulin （TM） was excluded from the proband. A mutation analysis was performed by amplification and sequencing of the APOH gene. Wild type and mutant （c.112A〉G） APOH expression plasmids were constructed and transfected into HEK293T cells. The results showed that the thrornbin generation capacity of the proband was higher than that of the other family members. Missense mutation p.Lys38Glu in APOH gene and LA coexisted in the proband. The mutation led to β2GPI deficiency and thrombosis by impairing the protein production and inhibiting the platelet aggregation. It was concluded that the recurrent thrombosis of the proband is associated with the coexistence ofp.Lys38Glu mutation in APOH gene and LA in plasma.
文摘Background Data regarding the influence of weekends and Chinese national holiday＇s admission on the outcomes of patients with ST-elevated myocardial infarction （STEMI） is lacking. This study sought to investigate the effect of Chinese national holidays and weekend admission on outcomes in patients with STEMI undergoing primary percutaneous coronary intervention （PPCI）. Methods Patients pre- senting with STEMI within 12 h of symptom onset who underwent PPCI were retrospectively enrolled. The primary outcome of in-hospital mortality and major adverse cardiovascular events in patients presenting Chinese national holiday＇s and weekends versus weekdays was evaluated. Results A total of 441 STEMI patients were enrolled in this study. Of these, 129 （29.3%） patients were admitted during Chinese national holidays and weekends and 312 （70.7%） during weekdays. Patients admitted during holidays and weekends were more likely to present with Killip class Ⅲ-Ⅳ. Patients admitted during holidays and weekends experienced a significantly longer door-to-baUoon time, symptom onset-to-door time as well as symptom onset-to-balloon time. The in-hospital mortality between patients presenting holidays and weekends versus weekdays was comparable. However, patients admitted during holidays and weekends have a signitieantly higher rate of in-hospital major adverse cardiovascular events. Multivariate analysis demonstrated that holidays and weekends admission was independ- ently associated with adverse outcomes. Conclusions In China, STEMI patients undergoing PPCI during national holidays and weekends have worse in-hospital outcomes compared to those admitted during weekdays. These findings suggest that continuous efforts should be undertaken to enhance the Chinese healthcare system and to ensure that comparable outcomes are achieved for all STEMI patients regardless of time of presentation.
基金supported by the funding from Beijing municipal high level innovative team building program(IDHT20190503)the National Natural Science Foundation of China(22075006)。
文摘The particle morphology determined by the sintering process is the director factor affecting the electrochemical performance of Ni-rich NMC cathode materials.To prepare the ideal NMC particles,it is of great significance to understand the morphological changes during sintering process.In this work,the morphology evolution of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)synthesis at temperature ranging from 300–1080℃were observed by in situ SEM.The uniform mixture of spherical Ni_(0.8)Mn_(0.1)Co_(0.1)(OH)_(2)precursor and lithium sources(LiOH)was employed by high temperature solid-state process inside the SEM,which enables us to observe morphology changes in real time.The results show that synthetic reaction of LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)usually includes three processes:the raw materials’dehydration,oxidation,and combination,accompanied by a significant reduction in particle size,which is important reference to control the synthesis temperature.As heating temperature rise,the morphology of mixture also changed from flake to brick-shaped.However,Ni nanoparticle formation is apparent at higher temperature~1000℃,suggesting a structural transformation from a layered to a rock-salt-like structure.Combining the in-situ observed changes in size and morphology,and with the premise of ensuring the morphology change from flakes to bricks,reducing the sintering temperature as much as possible to prevent excessive reduction in particle size and layered to a rock-salt structure transformation is recommended for prepare ideal NMC particles.
基金supported by National Nature Science Foundation of China(Project No.3057 2046,30725042)
文摘Aim To characterize the odontogenic capability of apical bud and phenotypical change of apical bud cells （ABCs） in different microenvironment.Methodology Incisor apical bud tissues from neonatal SD rat were dissected and transplanted into the renal capsules to determine their odontogenic capability. Meanwhile ABCs were cultured and purified by repeated differential trypsinization. Then ABCs were cultured with conditioned medium from developing apical complex cells （DAC-CM）. Immunocytochemistry, reverse transcriptase polymerase chain reaction （RT-PCR） and scanning electron microscope （SEM） were performed to compare the biolo- gical change of ABC treated with or without DAC-CM. Results First we confirmed the ability of apical bud to form crown-like structure ectopically. Equally important, by using the developing apical complex （DAC） condi- tioned medium, we found the microenvironment created by root could abrogate the ＂crown＂ features of ABCs and promote their proliferation and differentiation. Conclusion ABCs possess odontogenic capability to form crown-like tissues and this property can be affected by root-produced microenvironment.
基金support for this research from the State Key Program of National Natural Science of China (Grant No. 41430634)the National Natural Science Foundation of China (Grant Nos. 41702382, 51578195, 51378161, and 51308547)+1 种基金the Foundation Project Program 973 of China (No. 2012CB026104)the State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining & Technology (Grant No. SKLGDUEK1209)
文摘Maximum frost heave of unsaturated frost-susceptible soils,in conjunction with a high water table,is an important consideration for the design of foundations in seasonally frozen regions.Therefore,it is necessary to evaluate accurately and efficiently the maximum frost heave for a given soil.For this purpose,a series of one-sided freezing experiments was conducted on unsaturated silty clay in an open system.Multistage cooling of sufficient duration was applied to the soil sample's top,while constant above-zero temperatures were maintained at the bottom.Then,a simple methodology for calculating maximum frost heave at a given cooling temperature was derived utilizing information obtained within the limited time allotted for each stage.On this basis,an empirical equation for defining maximum frost heave as a function of cooling temperature and overburden pressure was determined.Overall,this study provides a simple and practical procedure that is applicable to the evaluation of maximum frost heave of unsaturated frost-susceptible soils.
基金This research was funded by Natural Science Foundation of Beijing,China(No.3182005)National Natural Science Foundation of China(No.51635001)National Natural Science Foundation of China(No.50235008).
文摘A gear fault detection analysis method based on Fractional Wavelet Transform(FRWT)and Back Propagation Neural Network(BPNN)is proposed.Taking the changing order as the variable,the optimal order of gear vibration signals is determined by discrete fractional Fourier transform.Under the optimal order,the fractional wavelet transform is applied to eliminate noise from gear vibration signals.In this way,useful components of vibration signals can be successfully separated from background noise.Then,a set of feature vectors obtained by calculating the characteristic parameters for the de-noised signals are used to characterize the gear vibration features.Finally,the feature vectors are divided into two groups,including training samples and testing samples,which are input into the BPNN for learning and classification.Experimental results showed that this gear fault detection analysis method could well maintain the useful signal components related to gear faults and effectively extract the weak fault feature.The accuracy rate reached 96.67%in the identification of the type of gear fault.
基金supported by the National Natural Science Foundation of China(Nos.11675098,41430644,41473090,41373098)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT13078)
文摘Electron beam(EB) degradation of perfluorooctanoic acid(PFOA) and perfluorooctane sulfonate(PFOS) in aqueous solutions was studied. It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics, and degradation rates increased with increasing initial p H. Radical scavengers' experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS, especially hydrated electron. The decomposition efficiencies were 95.7% for PFOA and 85.9% for PFOS, by EB irradiation in an anoxic alkaline solution(p H = 13).The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH_2 unit were proposed.
基金supported by the National Key Research and Development Program of China(2019YFA0607404)the Natural Science Foundation of Jiangsu Province(BK20180523)+2 种基金the National Science Fund for Distinguished Young Scholars(31725020)the National Natural Science Foundation of China(31801260,31872848,41961124008,and 32021004)the China Scholarship Council。
文摘Extreme high-temperature stress(HTS) associated with climate change poses potential threats to wheat grain yield and quality. Wheat grain protein concentration(GPC) is a determinant of wheat quality for human nutrition and is often neglected in attempts to assess climate change impacts on wheat production. Crop models are useful tools for quantification of temperature impacts on grain yield and quality.Current crop models either cannot simulate or can simulate only partially the effects of HTS on crop N dynamics and grain N accumulation. There is a paucity of observational data on crop N and grain quality collected under systematic HTS scenarios to develop algorithms for model improvement as well as evaluate crop models. Two-year phytotron experiments were conducted with two wheat cultivars under HTS at anthesis, grain filling, and both stages. HTS significantly reduced total aboveground N and increased the rate of grain N accumulation, while total aboveground N and the rate of grain N accumulation were more sensitive to HTS at anthesis than at grain filling. The observed relationships between total aboveground N, rate of grain N accumulation, and HTS were quantified and incorporated into the WheatGrow model. The new HTS routines improved simulation of the dynamics of total aboveground N, grain N accumulation, and GPC by the model. The improved model provided better estimates of total aboveground N, grain N accumulation, and GPC under HTS(the normalized root mean square error was reduced by 40%, 85%, and 80%, respectively) than the original WheatGrow model. The improvements in the model enhance its applicability to the assessment of climate change effects on wheat grain quality by reducing the uncertainties of simulating N dynamics and grain quality under HTS.
基金financially supported by Sichuan Science and Technology Program(No.2023YFS0408)。
文摘The(ultra-)mafic mine tailings pond revealed a weathering discrepancy in the tailings profile,which provided a valuable analog to assess the role of carbonate and silicate weathering of the basalt.In this study,drill-cores samples were selected from the Wanniangou V–Ti–Fe mine tailings pond(Sichuan province,China)to investigate the mineralogicand geochemical characteristics in the tailings profile.The results reveal(1)the tailings pond profile consist of upper and lower layers.The upper layer is composed of carbonate weathering(1.4%),which was formed in the initial stages of tailings exposure and represented a minimal weathering degree.(2)The lower layer was primarily observed at the aquifer zone of the tailings pond,and was consistent with 0.45%carbonate weathering and 48.4%silicate weathering.(3)The weathering discrepancy in the tailings profile could be due to the sulfide oxidation and aerobic/flowing aquifer,which facilitate the water-tailings reactions.The tailings profile provides an analog to studying basalt weathering,as it spans both carbonate and silicate weathering.This research reinforces the idea that silicate weathering is predominant in basaltic areas and plays a crucial role in regulating atmospheric CO_(2)(carbon dioxide)levels on Earth.
基金Supported by the National Natural Science Foundation of China,No.81972230Hubei Technological Innovation Special Fund(CN),No.CXPJJH11800004-004,No.CXPJJH122002-063,and No.CXPJJH122002-092+6 种基金University Nursing Program for Young Scholar with Creative Talents in Heilongjiang Province,No.UNPYSCT-2017064Postdoctoral Foundation of Hei Long Jiang Province,No.LBH-Z20196 and No.LBH-Z20178China Postdoctoral Science Foundation,No.2021MD703835Wu Jie-Ping Medical Foundation,No.320.6750.2021-23-22Open Fund of Key Laboratory of Hepatosplenic Surgery,Ministery of Education,Harbin,China,No.GPKF202204Excellent Youth Science Fund of the First Hopital of Harbin Medical University,No.2021Y01Scientifc Foundation of the First Afliated Hospital of Harbin Medical University,No.2021B03。
文摘BACKGROUND Littoral cell angioma(LCA)is a rare benign vascular tumor of the spleen.Given its rarity,standard diagnostic and therapeutic recommendations have yet to be developed for reported cases.Splenectomy is the only method of obtaining a pathological diagnosis and providing treatment to obtain a favorable prognosis.CASE SUMMARY A 33-year-old female presented with abdominal pain for one month.Computed tomography and ultrasound revealed splenomegaly with multiple lesions and two accessory spleens.The patient underwent laparoscopic total splenectomy and accessory splenectomy,and splenic LCA was confirmed by pathology.Four months after surgery,the patient presented with acute liver failure,was readmitted,rapidly progressed to multiple organ dysfunction syndrome and died.CONCLUSION Preoperative diagnosis of LCA is challenging.We systematically reviewed online databases to identify the relevant literature and found a close relationship between malignancy and immunodysregulation.When a patient suffers from both splenic tumors and malignancy or immune-related disease,LCA is possible.Due to potential malignancy,total splenectomy(including accessory spleen)and regular follow-up after surgery are recommended.If LCA is diagnosed after surgery,a comprehensive postoperative examination is needed.
基金supported by the National Natural Science Foundation of China (Grant No. 41430634)the Foundation Project Program 973 of China (No. 2012CB026104)+2 种基金the Foundation Project Program of SHENHUA BAOSHEN Railway Corporation Limited (No. 201212240384)Technology Research and Development Plan Program of Heilongjiang Province, China (No. GZ13A009)State Key Laboratory for Geo Mechanics and Deep Underground Engineering, China University of Mining & Technology (Grant No. SKLGDUEK1209)
文摘Finite element simulations are increasingly providing a versatile environment for this topic. In this study, a two-dimensional finite element analysis is conducted to predict the deformation of high embankment in Bazhun heavy-haul railway, China. A recently developed nonlinear softening-type constitutive model is utilized to model the be- havior of subgrade filling materials subjected to freeze-thaw cycles. For the convenience of practical application, the dynamic loading induced by a vehicle is treated as a quasi-static axle load. The deformation of this embankment with different moisture content under freeze-thaw cycles is compared. The results show that when subjected to the first freeze-thaw cycle, the embankment experienced significant deformation variations. Maximum deformation was usually achieved after the embankment with optimum moisture content experienced six freeze-thaw cycles, however, the em- bankment with moisre content of 8.0% and 9.5% deforms continuously even after experiencing almost ten freeze-thaw cycles. Overall, this study provides a simple nonlinear finite element approach for calculating the deformation of the embankment in changing climate conditions.
