Hemoptysis is defined as bleeding originating from the respiratory tract distal to the larynx and is associated with a wide spectrum of underlying conditions,including bronchiectasis,pulmonary malignancies,tuberculosi...Hemoptysis is defined as bleeding originating from the respiratory tract distal to the larynx and is associated with a wide spectrum of underlying conditions,including bronchiectasis,pulmonary malignancies,tuberculosis,aspergillosis,and vascular malformations.^([1-3]) A metaanalysis involving patients with massive hemoptysis reported a mortality rate of 3.5%.^([4])This underscores the critical importance of prompt and eff ective embolization of the responsible artery to improve outcomes,particularly in patients presenting with life-threatening hemoptysis.展开更多
Previous studies have indicated a global reversal of near-surface wind speeds from a declining trend to an increasing trend around 2010;however,it remains unclear whether upper-air wind speeds exhibit a similar revers...Previous studies have indicated a global reversal of near-surface wind speeds from a declining trend to an increasing trend around 2010;however,it remains unclear whether upper-air wind speeds exhibit a similar reversal.This study evaluates reanalysis products using surface and radiosonde observations to analyze upper-air wind speed variations in the Northern Hemisphere,focusing on their seasonal and latitudinal differences.Results demonstrate that JRA-55 effectively captures wind speed variations in the Northern Hemisphere.Notably,upper-air wind speeds over land experienced a reversal in winter 2010 with significant latitudinal differences.The trend reversal of upper wind speed between the midlatitudes and subtropics presents a dipole pattern.From 1990 to 2010,upper-air wind speeds in the midlatitudes(40°-70°N)significantly declined,while the subtropical zone(20°-40°N)displayed an opposite trend.However,during 2010-2020,wind speeds in the midlatitudes shifted to a significant positive trend,whereas the subtropics experienced a significant negative trend.The variations in Northern Hemisphere winter wind speeds can be attributed to changes in low-level baroclinicity driven by tropical diabatic heating and midlatitude transient eddy feedback.Enhanced diabatic heating and weakened eddy feedback during 1990-2010 contributed to reduced wind speeds in the midlatitudes and increased speeds in the subtropics,while reduced diabatic heating and strengthened eddy feedback during 2010-2020 resulted in increased wind speeds in the midlatitudes and decreased speeds in the subtropics.The reversal of upper-air wind speeds could affect surface wind speeds by downward momentum transfer,which could contribute to the reversal of surface wind speeds.展开更多
Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the nume...Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal precipitation.However,solving a nonlinear problem through linear regression is significantly biased.This study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in China.The model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached 74.The PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,respectively.The observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.展开更多
Water stress is expected to intensify due to escalating atmospheric and surface dryness under global warming.Despite extensive research indicate that intensified dryness exacerbates water constraints on ecosystems,the...Water stress is expected to intensify due to escalating atmospheric and surface dryness under global warming.Despite extensive research indicate that intensified dryness exacerbates water constraints on ecosystems,the dynamics and underlying mechanisms of surface water stress(SWS)under climate change remain poorly understood.In this study,we use annual evaporative stress as the surface water stress index(WSI)and provide a comprehensive analysis of historical and projected global terrestrial SWS,covering its characteristic changes,driving factors,and impacts on vegetation.Our results show a significant declining trend in WSI during 1982–2014(-0.0033/decade,p<0.01),indicating the enhancement of SWS concurrent with a rapid expansion of water stress intensified areas at a rate of 1.85%/decade(p<0.01).Using the Budyko-Penman budget framework,we found that the intensification of SWS was primarily driven by an increase in vapor pressure deficit(VPD)and a decrease in precipitation.Furthermore,the intensification of SWS contributed to a decline in vegetation growth,with the extent of areas experiencing increased vegetation water deficit expanding rapidly at a rate of 1.38%per decade(p<0.01).In the future,SWS is projected to escalate,with the proportion of areas experiencing intensified SWS increasing from 6.3%to 24.3%by the end of the century under the SSP5–8.5.Our study provides a comprehensive analysis of the drivers of SWS under climate change and its impacts on ecosystems,offering valuable scientific insights for the effective management of water resources.展开更多
Characterized by scarce water resources and fragile ecosystems,Northwest China(NWC)has experienced a climate shift from warm-dry to warm-wet conditions since the 1980s that has garnered extensive concern in recent yea...Characterized by scarce water resources and fragile ecosystems,Northwest China(NWC)has experienced a climate shift from warm-dry to warm-wet conditions since the 1980s that has garnered extensive concern in recent years.In this study,the variability in extreme precipitation(EP)during 1961-2016 in different climate zones of NWC and the possible mechanisms for this variation are investigated.The results show that the EP trends significantly increased in most of the westerly zone(WZ)and plateau zone(PZ),while the EP trends did not significantly decrease in the monsoon zone(MZ).The start dates of extreme precipitation(SDEP)and end dates of extreme precipitation(EDEP)advanced and were postponed,respectively,in the WZ and PZ,while the opposite occurred in the MZ.Summer atmospheric circulation,water vapor transport,and atmospheric instability over NWC varied greatly with the interdecadal shift in EP before and after 1986.During 1986-2016,upper-level divergence and lower-level convergence occurred in the MZ and PZ,which strengthened ascending flow.In addition,the summer water vapor and atmospheric instability increased in the WZ and PZ.These characteristics created favorable conditions for increased occurrences of EP in the WZ and PZ in summer.Conversely,the upper-level convergence and lower-level divergence in the MZ strengthened descending flow.Decreases in summer water vapor and atmospheric instability occurred in the MZ after 1986.Hence,the environmental conditions in the MZ may have prevented the occurrence and development of EP in summer during 1986-2016.展开更多
At the time of writing,coronavirus disease 2019(COVID-19)is seriously threatening human lives and health throughout the world.Many epidemic models have been developed to provide references for decision-making by gover...At the time of writing,coronavirus disease 2019(COVID-19)is seriously threatening human lives and health throughout the world.Many epidemic models have been developed to provide references for decision-making by governments and the World Health Organization.To capture and understand the characteristics of the epidemic trend,parameter optimization algorithms are needed to obtain model parameters.In this study,the authors propose using the Levenberg–Marquardt algorithm(LMA)to identify epidemic models.This algorithm combines the advantage of the Gauss–Newton method and gradient descent method and has improved the stability of parameters.The authors selected four countries with relatively high numbers of confirmed cases to verify the advantages of the Levenberg–Marquardt algorithm over the traditional epidemiological model method.The results show that the Statistical-SIR(Statistical-Susceptible–Infected–Recovered)model using LMA can fit the actual curve of the epidemic well,while the epidemic simulation of the traditional model evolves too fast and the peak value is too high to reflect the real situation.展开更多
Recent research has shown that snow cover induces extreme wintertime cooling and has detrimental impacts.Although the dramatic loss of Arctic sea ice certainly has contributed to a more extreme climate,the mechanism c...Recent research has shown that snow cover induces extreme wintertime cooling and has detrimental impacts.Although the dramatic loss of Arctic sea ice certainly has contributed to a more extreme climate,the mechanism connecting sea-ice loss to extensive snow cover is still up for debate.In this study,a significant relationship between sea ice concentration(SIC)in the Barents-Kara(B-K)seas in November and snow cover extent over Eurasia in winter(November-January)has been found based in observational datasets and through numerical experiments.The reduction in B-K sea ice gives rise to a negative phase of Arctic Oscillation(AO),a deepened East Asia trough,and a shallow trough over Europe.These circulation anomalies lead to colder-than-normal Eurasian mid-latitude temperatures,providing favorable conditions for snowfall.In addition,two prominent cyclonic anomalies near Europe and Lake Baikal affect moisture transport and its divergence,which results in increased precipitation due to moisture advection and wind convergence.Furthermore,anomalous E-P flux shows that amplified upward propagating waves associated with the low SIC could contribute to the weakening of the polar vortex and southward breakouts of cold air.This work may be helpful for further understanding and predicting the snowfall conditions in the middle latitudes.展开更多
OBJECTIVE To explore whether MDM2 transfection can alter the MDM2-p53 autoregulatory feedback loop so as to change the sensitivity of ovarian cancer cell lines to cisplatin. METHODS The ovarian cancer cell line A2780 ...OBJECTIVE To explore whether MDM2 transfection can alter the MDM2-p53 autoregulatory feedback loop so as to change the sensitivity of ovarian cancer cell lines to cisplatin. METHODS The ovarian cancer cell line A2780 expressing wild-type P53 and the ovarian cancer cell line SKOV-3 with the p53 null type were stably transfected with pCMV-MDM2 or pCMV as a control. The blocked expression of P53 was determined by Western blots. Cytotoxicity was assessed using the MTT assay and the trypan blue exclusion assay. Flow cytometry was used to detect changes in the cell cycle and removal of platinum -DNA adducts was measured by atomic absorption spec-troscopy. RESULTS (1) Parental A2780 and A2780-V cells (IC50= 15.14±1.39 μmol) have similar cisplatin sensitivities, whereas sensitivity to cisplatin in A2780-M cells (IC50=7.98±1.32 μmol) was 2 to 3 fold greater (P=0.001). The trypan blue exclusion assay demonstrated that cisplatin killed a higher percentage of A2780-M cells compared to A2780-V cells. There was no significant change following MDM2 transfection in SKOV-3 cells. (2) After cisplatin treatment, A2780-M cells showed a pronounced S-phase arrest, however, A2780 cells with the intact wild-type P53, arrested primarily at the G2/M transition. (3) Platinum uptake was similar for all of the A2780 cell lines after ciaplatin treatment, but the removal of plat-inum-DNA adducts was reduced in the A2780-M cells compared with A2780-V cells. CONCLUSION MDM2 increases cisplatin cytotoxicity in ovarian cancer cells by blocking the expression of p53 through the MDM2-p53 autoregulatory feedback loop.展开更多
OBJECTIVE To study the effectiveness on the tumor load and cellular immune function of percutaneous cryoablation （argon-helium cryoablative system, AHCS） combined with transarterial chemoembolization （TACE） for tr...OBJECTIVE To study the effectiveness on the tumor load and cellular immune function of percutaneous cryoablation （argon-helium cryoablative system, AHCS） combined with transarterial chemoembolization （TACE） for treating large hepatocellular carcinomas （HCCs） with diameters over 10 ca. METHODS A total of 48 HCC patients were treated with AHCS after TACE. Tumor sizes ranged from 10 to 14 cm. All cases were a hypervascular type. There were 38 Child A cases and 10 Child B cases. Forty were AFP positive and 8 negative. The patients were randomized with therapy group consisting of 26 cases and the control group 22 cases. The therapy group received AHCS 4 weeks following TACE treatment. Reexamination included pathology, tumor markers, T-lymphocyte subgroup levels and computed tomography or MRI. The necrosis rate of the tumor load was calculated by Cavalieri＇s theory. EORTC QLQ-C30 was used in quality of life evaluation. RESULTS The average tumor-load reduction rate （necrosis rate） was 8.07% after TACE, and 28.65% after AHCS. Coagulation necrosis was produced in the target area. The tumor markers deceased significantly after AHCS. Tumor-load reduction after AHCS was more significant than after TACE. Suppression of cellular immunity after TACE was significant. In contrast, CD3^＋, CD4^＋ and NK increased after AHCS and an abnormal T-lymphocyte distribution was corrected. Quality of life after AHCS increased according to the EORTC QLQ-C30 evaluation. No severe complications occurred. CONCLUSION Percutaneous AHCS cryoablation after TACE reduced the tumor load in the short term. At the same time, cellular immune function was increased after AHCS. TACE was critical in increasing the therapeutic efficacy of AHCS because of its embolisation of blood vessels preventing a Flow Effect. Reduction of the tumor load in the short term may conduce to increase cellular immunity. Percutaneous AHCS cryoablation combined with TACE can reduce the tumor load, improve cellular immunity and increase quality of life of HCC patients. This type of therapy deserves to be studied further research.展开更多
Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave...Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave information from videos will be affected by the interference of the fine ripples on the sea surface.To solve this problem,this study develops a method for estimating peak wave periods from videos captured at low grazing angles.The method extracts the motion of the sea surface texture from the video and obtains the peak wave period via the spectral analysis.The calculation results captured from real-world videos are compared with those obtained from X-band radar inversion and tracking buoy movement,with maximum deviations of 8%and 14%,respectively.The analysis of the results shows that the peak wave period of the method has good stability.In addition,this paper uses a pinhole camera model to convert the displacement of the texture from pixel height to actual height and performs moving average filtering on the displacement of the texture,thus conducting a preliminary exploration of the inversion of significant wave height.This study helps to extend the application of sea surface videos.展开更多
Circularly polarized luminescent materials find extensive applications in 3D displays,information encryption,and photoinduced supramolecular chirality.However,controlling the handedness of circularly polarized lumines...Circularly polarized luminescent materials find extensive applications in 3D displays,information encryption,and photoinduced supramolecular chirality.However,controlling the handedness of circularly polarized luminescence remains a significant challenge in advancing optical technologies.In this study,we present a Janus circularly polarized light emitter comprising a fluorescent film combined with chiral nematic cellulose with switchable chirality.The emitter achieves maximum luminescence dissymmetry factors(0.28 and-0.65)through mode switching.In addition,we show the emitter’s versatility in inducing chiral helices in azobenzene polymers with varying polar groups,resulting in significant chiral signals.Importantly,the chirality of these polymers can be switched by altering the luminescence mode of the emitter.These results are expected to facilitate the efficient design of chiral luminescent materials and photoinduction devices.展开更多
The response to climate change and air pollution control demonstrates strong synergy across scientific mechanisms,targets,strategies,and governance systems.This report,based on a monitoring indicator system for coordi...The response to climate change and air pollution control demonstrates strong synergy across scientific mechanisms,targets,strategies,and governance systems.This report,based on a monitoring indicator system for coordinated governance of air pollution and climate change,employs an interdisciplinary approach combining natural and social sciences.It establishes 20 indicators across five key areas:air pollution and climate change,governance systems and practices,structural transformation and technologies,atmospheric components and emission reduction pathways,and health impacts and cobenefits.This report tries to provide actionable insights into the interconnectedness of air pollution and climate governance.It highlights key policy gaps,presents updated indicators,and offers a refined monitoring framework to track progress toward China's dual goals of reducing emissions and improving air quality.Compared to previous editions,this year's report has updated four key indicators:meteorological impacts on air quality,climate change and its effects,governance policies,and low-carbon building energy systems.The aim is to further refine the monitoring framework,track progress,and establish a comprehensive theory for collaborative governance while identifying challenges and proposing solutions for China's pathway to carbon neutrality and clean air.The report comprises six chapters.The executive summary chapter is followed by analyzing air pollution and climate change interactions.Governance systems and practices are discussed in the third chapter,focusing on policy implementation and local experiences.The fourth chapter addresses structural transformations and emission reduction technologies,including energy and industrial shifts,transportation,low-carbon buildings,carbon capture and storage,and power systems.The fifth chapter outlines atmospheric component dynamics and emission pathways,presenting insights into emission drivers and future strategies.The sixth chapter assesses health impacts and the benefits of coordinated actions.Since 2019,China Clean Air Policy Partnership has produced annual reports on China's progress in climate and air pollution governance,receiving positive feedback.In 2023,the report was co-developed with Tsinghua University's Carbon Neutrality Research Institute,involving over 100 experts and multiple academic forums.The collaboration aims to continuously improve the indicator system and establish the report as a key resource supporting China's efforts in pollution reduction,carbon mitigation,greening,and sustainable growth.展开更多
Achieving rubber-like stretchability in cellulose ionogels presents a substantial challenge due to the intrinsically extended chain configuration of cellulose.Inspired by the molecular configuration of natural rubber,...Achieving rubber-like stretchability in cellulose ionogels presents a substantial challenge due to the intrinsically extended chain configuration of cellulose.Inspired by the molecular configuration of natural rubber,we address this challenge by using cyanoethyl as a substitute for 1.5 hydroxyl on the D-glucose unit of cellulose.This strategy innovatively triggers the transformation of cellulose molecules into a coiled chain configuration,facilitating the creation of an ultra-stretchable ionogel free from any petrochemical polymers.The resultant ionogel demonstrates mechanical ductility comparable to that of a rubber band,achieving an elongation strain of nearly 1,000%while maintaining a tensile strength of up to 1.8 MPa and exhibiting a biomodulus akin to that of human skin,recorded at 63 kPa.Additionally,this stretchable ionogel presents skin-like self-healing behavior,favorable biocompatibility,and noteworthy thermoelectric properties,highlighted by a Seebeck coefficient of approximately 68 mV K−1.This study delineates a feasible molecular approach for developing stretchable ionogels from biomass resources,potentially revolutionizing self-powered stretchable electronics for integration with human tissues and skin.展开更多
Lignin is the most promising candidate for producing aromatic compounds from biomass.However,the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions,as these bonds have high disso...Lignin is the most promising candidate for producing aromatic compounds from biomass.However,the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions,as these bonds have high dissociation energy.Electrochemical oxidation,which allows for mild cleavage of C-C bonds,is considered an attractive solution.To achieve low-energy consumption in the valorization of lignin,the use of highly efficient electrocatalysts is essential.In this study,a meticulously designed catalyst consisting of cobalt-doped nickel(oxy)hydroxide on molybdenum disulfide heterojunction was developed.The presence of molybdenum in a high valence state promoted the adsorption of tert-butyl hydroperoxide,leading to the formation of critical radical intermediates.In addition,the incorporation of cobalt doping regulated the electronic structure of nickel,resulting in a lower energy barrier.As a result,the heterojunction catalyst demonstrated a selectivity of 85.36% for cleaving the C_(α)-C_(β)bond in lignin model compound,achieving a substrate conversion of 93.69% under ambient conditions.In addition,the electrocatalyst depolymerized 49.82 wt% of soluble fractions from organosolv lignin(OL),resulting in a yield of up to 13 wt% of aromatic monomers.Significantly,the effectiveness of the prepared electrocatalyst was also demonstrated using industrial Kraft lignin(KL).Therefore,this research offers a practical approach for implementing electrocatalytic oxidation in lignin refining.展开更多
The conductive polymer poly-3,4-ethylenedioxythiophene(PEDOT),recognized for its superior electrical conductivity and biocompatibility,has become an attractive material for developing wearable technologies and bioelec...The conductive polymer poly-3,4-ethylenedioxythiophene(PEDOT),recognized for its superior electrical conductivity and biocompatibility,has become an attractive material for developing wearable technologies and bioelectronics.Nevertheless,the complexities associated with PEDOT's patterning synthesis on diverse substrates persist despite recent technological progress.In this study,we introduce a novel deep eutectic solvent(DES)-induced vapor phase polymerization technique,facilitating nonrestrictive patterning polymerization of PEDOT across diverse substrates.By controlling the quantity of DES adsorbed per unit area on the substrates,PEDOT can be effectively patternized on cellulose,wood,plastic,glass,and even hydrogels.The resultant patterned PEDOT exhibits numerous benefits,such as an impressive electronic conductivity of 282 S·m-1,a high specific surface area of 5.29 m^(2)·g-1,and an extensive electrochemical stability range from-1.4 to 2.4 V in a phosphate-buffered saline.To underscore the practicality and diverse applications of this DES-induced approach,we present multiple examples emphasizing its integration into self-supporting flexible electrodes,neuroelectrode interfaces,and precision circuit repair methodologies.展开更多
Ecosystem transition occurs when ecological thresholds are crossed,causing ecosystems to irreversibly shift from secure to insecure states.However,how ecosystem transition exacerbates species richness loss remains poo...Ecosystem transition occurs when ecological thresholds are crossed,causing ecosystems to irreversibly shift from secure to insecure states.However,how ecosystem transition exacerbates species richness loss remains poorly understood.This hinders the effective protection of species richness,which is an urgent global priority.In this study,we integrated multiple ecosystem variables to elucidate ecosystem transition and its impacts on species richness loss.Our findings reveal that species richness declines abruptly following ecosystem transition,as insecure ecosystems are characterized by reduced plant cover and productivity,intensified warming and drying,and diminished oxygen production.Insecure ecosystems imperil the survival of all species,including 39.4%of threatened birds and 29.2%of threatened mammal species.We project that by 2100,the ecosystem areas considered insecure will encompass 40.4%of the global land areas under the RCP8.5 scenario,contributing to 51.6%of species richness loss.In contrast,hyper-secure ecosystems are projected to account for 18.1%of species richness loss.This study identifies ecosystem transition as a critical driver of species richness loss that should be accounted for by policymakers in designing targeted conservation strategies.展开更多
Arid and semi-arid regions constitute approximately one-third of the total land area in China and are vulnerable to the effects of global climate change.Over the past century,a large number of studies have investigate...Arid and semi-arid regions constitute approximately one-third of the total land area in China and are vulnerable to the effects of global climate change.Over the past century,a large number of studies have investigated regional climate change and its impacts.However,the conclusions are inconsistent due to differing research perspectives,and this has highlighted the urgent need to obtain systematic,scientific knowledge through review and synthesis.This study,based on a survey of all available literature,reviews the evolution of regional climate change and its effects in the arid and semi-arid regions of China over the last century.The present review examines three aspects of the surveyed previous studies:data,methods,and subjects,and then summarizes essential scientific findings into four subject areas:the origin and expansion of arid and semi-arid regions,the characteristics of climate change in these areas,the drivers of climate change in arid and semi-arid zones,and the consequences of climate change in such environments.Finally,six key directions for future research on climate change and its effects on the arid and semi-arid regions of China are proposed.展开更多
Addressing climate change and air pollution exhibits strong synergy,and the Chinese government is actively promoting the integrated management of these two issues.Since 2019,the China Clean Air Policy Partnership has ...Addressing climate change and air pollution exhibits strong synergy,and the Chinese government is actively promoting the integrated management of these two issues.Since 2019,the China Clean Air Policy Partnership has released annual reports on China's progress in climate and air pollution governance.These reports track and analyze the challenges and propose solutions for China's pursuit of carbon neutrality and clean air by developing and monitoring key indicators across five areas.This report is the fourth annual report.Building on previous research,it further refines the collaborative governance monitoring indicator system,including the addition of climate change and extreme weather,atmospheric greenhouse gases,and enhanced efficiency of pollution removal technologies.The report includes the following components:(1)an analysis of the interactions between air pollution and climate change;(2)a discussion of governance systems and practices,with an emphasis on policy implementation and local experiences;(3)coverage of structural changes and emission reduction technologies,including energy and industrial transitions,transportation,low-carbon buildings,carbon capture and storage,and power systems;(4)an overview of atmospheric dynamics and emission pathways,examining emission drivers and offering insights for future coordinated governance;and(5)an evaluation of the health impacts and benefits of joint actions.These efforts underscore China's commitment to integrated control,resulting in slowed carbon emission growth,improved air quality,and enhanced health benefits.展开更多
文摘Hemoptysis is defined as bleeding originating from the respiratory tract distal to the larynx and is associated with a wide spectrum of underlying conditions,including bronchiectasis,pulmonary malignancies,tuberculosis,aspergillosis,and vascular malformations.^([1-3]) A metaanalysis involving patients with massive hemoptysis reported a mortality rate of 3.5%.^([4])This underscores the critical importance of prompt and eff ective embolization of the responsible artery to improve outcomes,particularly in patients presenting with life-threatening hemoptysis.
基金supported by the National Natural Science Foundation of China[grant numbers U2442207,42122034,42075043,and 42330609]the Youth Innovation Promotion Association[grant number 2021427]+2 种基金the West Light Foundation[grant number xbzgzdsys-202409]of the Chinese Academy of Sciencesthe Key Talent Projects in Gansu Provincethe Central Guidance Fund for Local Science and Technology Development Projects in Gansu Province[grant number 24ZYQA031].
文摘Previous studies have indicated a global reversal of near-surface wind speeds from a declining trend to an increasing trend around 2010;however,it remains unclear whether upper-air wind speeds exhibit a similar reversal.This study evaluates reanalysis products using surface and radiosonde observations to analyze upper-air wind speed variations in the Northern Hemisphere,focusing on their seasonal and latitudinal differences.Results demonstrate that JRA-55 effectively captures wind speed variations in the Northern Hemisphere.Notably,upper-air wind speeds over land experienced a reversal in winter 2010 with significant latitudinal differences.The trend reversal of upper wind speed between the midlatitudes and subtropics presents a dipole pattern.From 1990 to 2010,upper-air wind speeds in the midlatitudes(40°-70°N)significantly declined,while the subtropical zone(20°-40°N)displayed an opposite trend.However,during 2010-2020,wind speeds in the midlatitudes shifted to a significant positive trend,whereas the subtropics experienced a significant negative trend.The variations in Northern Hemisphere winter wind speeds can be attributed to changes in low-level baroclinicity driven by tropical diabatic heating and midlatitude transient eddy feedback.Enhanced diabatic heating and weakened eddy feedback during 1990-2010 contributed to reduced wind speeds in the midlatitudes and increased speeds in the subtropics,while reduced diabatic heating and strengthened eddy feedback during 2010-2020 resulted in increased wind speeds in the midlatitudes and decreased speeds in the subtropics.The reversal of upper-air wind speeds could affect surface wind speeds by downward momentum transfer,which could contribute to the reversal of surface wind speeds.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42122034,42075043,42330609)the Second Tibetan Plateau Scientific Expedition and Research program(2019QZKK0103)+2 种基金Key Talent Project in Gansu and Central Guidance Fund for Local Science and Technology Development Projects in Gansu(No.24ZYQA031)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021427)West Light Foundation of the Chinese Academy of Sciences(xbzg-zdsys-202215)。
文摘Seasonal precipitation has always been a key focus of climate prediction.As a dynamic-statistical combined method,the existing observational constraint correction establishes a regression relationship between the numerical model outputs and historical observations,which can partly predict seasonal precipitation.However,solving a nonlinear problem through linear regression is significantly biased.This study implements a nonlinear optimization of an existing observational constrained correction model using a Light Gradient Boosting Machine(LightGBM)machine learning algorithm based on output from the Beijing National Climate Center Climate System Model(BCC-CSM)and station observations to improve the prediction of summer precipitation in China.The model was trained using a rolling approach,and LightGBM outperformed Linear Regression(LR),Extreme Gradient Boosting(XGBoost),and Categorical Boosting(CatBoost).Using parameter tuning to optimize the machine learning model and predict future summer precipitation using eight different predictors in BCC-CSM,the mean Anomaly Correlation Coefficient(ACC)score in the 2019–22 summer precipitation predictions was 0.17,and the mean Prediction Score(PS)reached 74.The PS score was improved by 7.87%and 6.63%compared with the BCC-CSM and the linear observational constraint approach,respectively.The observational constraint correction prediction strategy with LightGBM significantly and stably improved the prediction of summer precipitation in China compared to the previous linear observational constraint solution,providing a reference for flood control and drought relief during the flood season(summer)in China.
基金jointly supported by the National Natural Science Foundation of China(Grant No.U2442207)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2021427)+1 种基金the West Light Foundation(Grant No.xbzg-zdsys-202409)of the Chinese Academy of SciencesKey Talent Project in Gansu and Central Guidance Fund for Local Science and Technology Development Projects in Gansu(Grant No.24ZYQA031)。
文摘Water stress is expected to intensify due to escalating atmospheric and surface dryness under global warming.Despite extensive research indicate that intensified dryness exacerbates water constraints on ecosystems,the dynamics and underlying mechanisms of surface water stress(SWS)under climate change remain poorly understood.In this study,we use annual evaporative stress as the surface water stress index(WSI)and provide a comprehensive analysis of historical and projected global terrestrial SWS,covering its characteristic changes,driving factors,and impacts on vegetation.Our results show a significant declining trend in WSI during 1982–2014(-0.0033/decade,p<0.01),indicating the enhancement of SWS concurrent with a rapid expansion of water stress intensified areas at a rate of 1.85%/decade(p<0.01).Using the Budyko-Penman budget framework,we found that the intensification of SWS was primarily driven by an increase in vapor pressure deficit(VPD)and a decrease in precipitation.Furthermore,the intensification of SWS contributed to a decline in vegetation growth,with the extent of areas experiencing increased vegetation water deficit expanding rapidly at a rate of 1.38%per decade(p<0.01).In the future,SWS is projected to escalate,with the proportion of areas experiencing intensified SWS increasing from 6.3%to 24.3%by the end of the century under the SSP5–8.5.Our study provides a comprehensive analysis of the drivers of SWS under climate change and its impacts on ecosystems,offering valuable scientific insights for the effective management of water resources.
基金The authors would like to extend sincere gratitude for the support from the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0103)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA2006010101)+2 种基金the National Natural Science Foundation of China(91837208)the National Key Research and Development Program of China(2018YFC1505701)This work was jointly supported by the National Natural Science Foundation of China(42075043)and the Youth Innovation Promotion Association CAS.
文摘Characterized by scarce water resources and fragile ecosystems,Northwest China(NWC)has experienced a climate shift from warm-dry to warm-wet conditions since the 1980s that has garnered extensive concern in recent years.In this study,the variability in extreme precipitation(EP)during 1961-2016 in different climate zones of NWC and the possible mechanisms for this variation are investigated.The results show that the EP trends significantly increased in most of the westerly zone(WZ)and plateau zone(PZ),while the EP trends did not significantly decrease in the monsoon zone(MZ).The start dates of extreme precipitation(SDEP)and end dates of extreme precipitation(EDEP)advanced and were postponed,respectively,in the WZ and PZ,while the opposite occurred in the MZ.Summer atmospheric circulation,water vapor transport,and atmospheric instability over NWC varied greatly with the interdecadal shift in EP before and after 1986.During 1986-2016,upper-level divergence and lower-level convergence occurred in the MZ and PZ,which strengthened ascending flow.In addition,the summer water vapor and atmospheric instability increased in the WZ and PZ.These characteristics created favorable conditions for increased occurrences of EP in the WZ and PZ in summer.Conversely,the upper-level convergence and lower-level divergence in the MZ strengthened descending flow.Decreases in summer water vapor and atmospheric instability occurred in the MZ after 1986.Hence,the environmental conditions in the MZ may have prevented the occurrence and development of EP in summer during 1986-2016.
基金This work was jointly supported by the National Natural Science Foundation of China[grant number 41521004]the Gansu Provincial Special Fund Project for Guiding Scientific and Technological Innovation and Development[grant number 2019ZX-06].
文摘At the time of writing,coronavirus disease 2019(COVID-19)is seriously threatening human lives and health throughout the world.Many epidemic models have been developed to provide references for decision-making by governments and the World Health Organization.To capture and understand the characteristics of the epidemic trend,parameter optimization algorithms are needed to obtain model parameters.In this study,the authors propose using the Levenberg–Marquardt algorithm(LMA)to identify epidemic models.This algorithm combines the advantage of the Gauss–Newton method and gradient descent method and has improved the stability of parameters.The authors selected four countries with relatively high numbers of confirmed cases to verify the advantages of the Levenberg–Marquardt algorithm over the traditional epidemiological model method.The results show that the Statistical-SIR(Statistical-Susceptible–Infected–Recovered)model using LMA can fit the actual curve of the epidemic well,while the epidemic simulation of the traditional model evolves too fast and the peak value is too high to reflect the real situation.
基金financially supported by the International Partnership Program of Chinese Academy of Sciences (Grant No. 131B62KYSB20180003)the Frontier Science Key Project of CAS (Grant No. QYZDY-SSW-DQC021)the State Key Laboratory of Cryospheric Science (Grant No. SKLCSZZ-2022)
文摘Recent research has shown that snow cover induces extreme wintertime cooling and has detrimental impacts.Although the dramatic loss of Arctic sea ice certainly has contributed to a more extreme climate,the mechanism connecting sea-ice loss to extensive snow cover is still up for debate.In this study,a significant relationship between sea ice concentration(SIC)in the Barents-Kara(B-K)seas in November and snow cover extent over Eurasia in winter(November-January)has been found based in observational datasets and through numerical experiments.The reduction in B-K sea ice gives rise to a negative phase of Arctic Oscillation(AO),a deepened East Asia trough,and a shallow trough over Europe.These circulation anomalies lead to colder-than-normal Eurasian mid-latitude temperatures,providing favorable conditions for snowfall.In addition,two prominent cyclonic anomalies near Europe and Lake Baikal affect moisture transport and its divergence,which results in increased precipitation due to moisture advection and wind convergence.Furthermore,anomalous E-P flux shows that amplified upward propagating waves associated with the low SIC could contribute to the weakening of the polar vortex and southward breakouts of cold air.This work may be helpful for further understanding and predicting the snowfall conditions in the middle latitudes.
文摘OBJECTIVE To explore whether MDM2 transfection can alter the MDM2-p53 autoregulatory feedback loop so as to change the sensitivity of ovarian cancer cell lines to cisplatin. METHODS The ovarian cancer cell line A2780 expressing wild-type P53 and the ovarian cancer cell line SKOV-3 with the p53 null type were stably transfected with pCMV-MDM2 or pCMV as a control. The blocked expression of P53 was determined by Western blots. Cytotoxicity was assessed using the MTT assay and the trypan blue exclusion assay. Flow cytometry was used to detect changes in the cell cycle and removal of platinum -DNA adducts was measured by atomic absorption spec-troscopy. RESULTS (1) Parental A2780 and A2780-V cells (IC50= 15.14±1.39 μmol) have similar cisplatin sensitivities, whereas sensitivity to cisplatin in A2780-M cells (IC50=7.98±1.32 μmol) was 2 to 3 fold greater (P=0.001). The trypan blue exclusion assay demonstrated that cisplatin killed a higher percentage of A2780-M cells compared to A2780-V cells. There was no significant change following MDM2 transfection in SKOV-3 cells. (2) After cisplatin treatment, A2780-M cells showed a pronounced S-phase arrest, however, A2780 cells with the intact wild-type P53, arrested primarily at the G2/M transition. (3) Platinum uptake was similar for all of the A2780 cell lines after ciaplatin treatment, but the removal of plat-inum-DNA adducts was reduced in the A2780-M cells compared with A2780-V cells. CONCLUSION MDM2 increases cisplatin cytotoxicity in ovarian cancer cells by blocking the expression of p53 through the MDM2-p53 autoregulatory feedback loop.
文摘OBJECTIVE To study the effectiveness on the tumor load and cellular immune function of percutaneous cryoablation （argon-helium cryoablative system, AHCS） combined with transarterial chemoembolization （TACE） for treating large hepatocellular carcinomas （HCCs） with diameters over 10 ca. METHODS A total of 48 HCC patients were treated with AHCS after TACE. Tumor sizes ranged from 10 to 14 cm. All cases were a hypervascular type. There were 38 Child A cases and 10 Child B cases. Forty were AFP positive and 8 negative. The patients were randomized with therapy group consisting of 26 cases and the control group 22 cases. The therapy group received AHCS 4 weeks following TACE treatment. Reexamination included pathology, tumor markers, T-lymphocyte subgroup levels and computed tomography or MRI. The necrosis rate of the tumor load was calculated by Cavalieri＇s theory. EORTC QLQ-C30 was used in quality of life evaluation. RESULTS The average tumor-load reduction rate （necrosis rate） was 8.07% after TACE, and 28.65% after AHCS. Coagulation necrosis was produced in the target area. The tumor markers deceased significantly after AHCS. Tumor-load reduction after AHCS was more significant than after TACE. Suppression of cellular immunity after TACE was significant. In contrast, CD3^＋, CD4^＋ and NK increased after AHCS and an abnormal T-lymphocyte distribution was corrected. Quality of life after AHCS increased according to the EORTC QLQ-C30 evaluation. No severe complications occurred. CONCLUSION Percutaneous AHCS cryoablation after TACE reduced the tumor load in the short term. At the same time, cellular immune function was increased after AHCS. TACE was critical in increasing the therapeutic efficacy of AHCS because of its embolisation of blood vessels preventing a Flow Effect. Reduction of the tumor load in the short term may conduce to increase cellular immunity. Percutaneous AHCS cryoablation combined with TACE can reduce the tumor load, improve cellular immunity and increase quality of life of HCC patients. This type of therapy deserves to be studied further research.
基金The Key R&D Program of Shandong Province under contract No.2023CXPT101.
文摘Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave information from videos will be affected by the interference of the fine ripples on the sea surface.To solve this problem,this study develops a method for estimating peak wave periods from videos captured at low grazing angles.The method extracts the motion of the sea surface texture from the video and obtains the peak wave period via the spectral analysis.The calculation results captured from real-world videos are compared with those obtained from X-band radar inversion and tracking buoy movement,with maximum deviations of 8%and 14%,respectively.The analysis of the results shows that the peak wave period of the method has good stability.In addition,this paper uses a pinhole camera model to convert the displacement of the texture from pixel height to actual height and performs moving average filtering on the displacement of the texture,thus conducting a preliminary exploration of the inversion of significant wave height.This study helps to extend the application of sea surface videos.
基金supported by the National Key R&D Program of China(2023YFD2201405)the National Natural Science Foundation of China(32471804,32401514)+2 种基金the Canada Excellence Research Chair Program(CERC-2018-00006)the Canada Foundation for Innovation(38623)the Pacific Economic Development Canada(PacifiCAN).
文摘Circularly polarized luminescent materials find extensive applications in 3D displays,information encryption,and photoinduced supramolecular chirality.However,controlling the handedness of circularly polarized luminescence remains a significant challenge in advancing optical technologies.In this study,we present a Janus circularly polarized light emitter comprising a fluorescent film combined with chiral nematic cellulose with switchable chirality.The emitter achieves maximum luminescence dissymmetry factors(0.28 and-0.65)through mode switching.In addition,we show the emitter’s versatility in inducing chiral helices in azobenzene polymers with varying polar groups,resulting in significant chiral signals.Importantly,the chirality of these polymers can be switched by altering the luminescence mode of the emitter.These results are expected to facilitate the efficient design of chiral luminescent materials and photoinduction devices.
基金supported by the National Key Research and Development Program of China(2022YFC3702704)the National Natural Science Foundation of China(42293324)the Energy Foundation,China.
文摘The response to climate change and air pollution control demonstrates strong synergy across scientific mechanisms,targets,strategies,and governance systems.This report,based on a monitoring indicator system for coordinated governance of air pollution and climate change,employs an interdisciplinary approach combining natural and social sciences.It establishes 20 indicators across five key areas:air pollution and climate change,governance systems and practices,structural transformation and technologies,atmospheric components and emission reduction pathways,and health impacts and cobenefits.This report tries to provide actionable insights into the interconnectedness of air pollution and climate governance.It highlights key policy gaps,presents updated indicators,and offers a refined monitoring framework to track progress toward China's dual goals of reducing emissions and improving air quality.Compared to previous editions,this year's report has updated four key indicators:meteorological impacts on air quality,climate change and its effects,governance policies,and low-carbon building energy systems.The aim is to further refine the monitoring framework,track progress,and establish a comprehensive theory for collaborative governance while identifying challenges and proposing solutions for China's pathway to carbon neutrality and clean air.The report comprises six chapters.The executive summary chapter is followed by analyzing air pollution and climate change interactions.Governance systems and practices are discussed in the third chapter,focusing on policy implementation and local experiences.The fourth chapter addresses structural transformations and emission reduction technologies,including energy and industrial shifts,transportation,low-carbon buildings,carbon capture and storage,and power systems.The fifth chapter outlines atmospheric component dynamics and emission pathways,presenting insights into emission drivers and future strategies.The sixth chapter assesses health impacts and the benefits of coordinated actions.Since 2019,China Clean Air Policy Partnership has produced annual reports on China's progress in climate and air pollution governance,receiving positive feedback.In 2023,the report was co-developed with Tsinghua University's Carbon Neutrality Research Institute,involving over 100 experts and multiple academic forums.The collaboration aims to continuously improve the indicator system and establish the report as a key resource supporting China's efforts in pollution reduction,carbon mitigation,greening,and sustainable growth.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFD2200504)the Central Guidance Fund for Local Science and Technology Development Projects(Grant No.2024JH6/100700013)+1 种基金the National Natural Science Foundation of China(Grant Nos.32171720 and 32371823)the National Science Fund for Distinguished Young Scholars(Grant No.31925028).
文摘Achieving rubber-like stretchability in cellulose ionogels presents a substantial challenge due to the intrinsically extended chain configuration of cellulose.Inspired by the molecular configuration of natural rubber,we address this challenge by using cyanoethyl as a substitute for 1.5 hydroxyl on the D-glucose unit of cellulose.This strategy innovatively triggers the transformation of cellulose molecules into a coiled chain configuration,facilitating the creation of an ultra-stretchable ionogel free from any petrochemical polymers.The resultant ionogel demonstrates mechanical ductility comparable to that of a rubber band,achieving an elongation strain of nearly 1,000%while maintaining a tensile strength of up to 1.8 MPa and exhibiting a biomodulus akin to that of human skin,recorded at 63 kPa.Additionally,this stretchable ionogel presents skin-like self-healing behavior,favorable biocompatibility,and noteworthy thermoelectric properties,highlighted by a Seebeck coefficient of approximately 68 mV K−1.This study delineates a feasible molecular approach for developing stretchable ionogels from biomass resources,potentially revolutionizing self-powered stretchable electronics for integration with human tissues and skin.
基金supported by the National Science Fund for Distinguished Young Scholars(grant no.31925028)the National Natural Science Foundation of China(grant no.22102019)the Natural Science Foundation of Heilongjiang Province(no.YQ2021C005).
文摘Lignin is the most promising candidate for producing aromatic compounds from biomass.However,the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions,as these bonds have high dissociation energy.Electrochemical oxidation,which allows for mild cleavage of C-C bonds,is considered an attractive solution.To achieve low-energy consumption in the valorization of lignin,the use of highly efficient electrocatalysts is essential.In this study,a meticulously designed catalyst consisting of cobalt-doped nickel(oxy)hydroxide on molybdenum disulfide heterojunction was developed.The presence of molybdenum in a high valence state promoted the adsorption of tert-butyl hydroperoxide,leading to the formation of critical radical intermediates.In addition,the incorporation of cobalt doping regulated the electronic structure of nickel,resulting in a lower energy barrier.As a result,the heterojunction catalyst demonstrated a selectivity of 85.36% for cleaving the C_(α)-C_(β)bond in lignin model compound,achieving a substrate conversion of 93.69% under ambient conditions.In addition,the electrocatalyst depolymerized 49.82 wt% of soluble fractions from organosolv lignin(OL),resulting in a yield of up to 13 wt% of aromatic monomers.Significantly,the effectiveness of the prepared electrocatalyst was also demonstrated using industrial Kraft lignin(KL).Therefore,this research offers a practical approach for implementing electrocatalytic oxidation in lignin refining.
基金supported by the National Science Fund for Distinguished Young Scholars(no.31925028)the National Natural Science Foundation of China(nos.32171720 and 32371823).
文摘The conductive polymer poly-3,4-ethylenedioxythiophene(PEDOT),recognized for its superior electrical conductivity and biocompatibility,has become an attractive material for developing wearable technologies and bioelectronics.Nevertheless,the complexities associated with PEDOT's patterning synthesis on diverse substrates persist despite recent technological progress.In this study,we introduce a novel deep eutectic solvent(DES)-induced vapor phase polymerization technique,facilitating nonrestrictive patterning polymerization of PEDOT across diverse substrates.By controlling the quantity of DES adsorbed per unit area on the substrates,PEDOT can be effectively patternized on cellulose,wood,plastic,glass,and even hydrogels.The resultant patterned PEDOT exhibits numerous benefits,such as an impressive electronic conductivity of 282 S·m-1,a high specific surface area of 5.29 m^(2)·g-1,and an extensive electrochemical stability range from-1.4 to 2.4 V in a phosphate-buffered saline.To underscore the practicality and diverse applications of this DES-induced approach,we present multiple examples emphasizing its integration into self-supporting flexible electrodes,neuroelectrode interfaces,and precision circuit repair methodologies.
基金jointly supported by the National Natural Science Foundation of China(41991231 and 42041004)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0602)the China University Research Talents Recruitment Program(111 project,B13045)。
文摘Ecosystem transition occurs when ecological thresholds are crossed,causing ecosystems to irreversibly shift from secure to insecure states.However,how ecosystem transition exacerbates species richness loss remains poorly understood.This hinders the effective protection of species richness,which is an urgent global priority.In this study,we integrated multiple ecosystem variables to elucidate ecosystem transition and its impacts on species richness loss.Our findings reveal that species richness declines abruptly following ecosystem transition,as insecure ecosystems are characterized by reduced plant cover and productivity,intensified warming and drying,and diminished oxygen production.Insecure ecosystems imperil the survival of all species,including 39.4%of threatened birds and 29.2%of threatened mammal species.We project that by 2100,the ecosystem areas considered insecure will encompass 40.4%of the global land areas under the RCP8.5 scenario,contributing to 51.6%of species richness loss.In contrast,hyper-secure ecosystems are projected to account for 18.1%of species richness loss.This study identifies ecosystem transition as a critical driver of species richness loss that should be accounted for by policymakers in designing targeted conservation strategies.
基金Supported by the National Natural Science Foundation of China(42230611 and 42375039)Natural Science Foundation of Gansu Province(23JRRA1324 and 24JRRA725)Key Talent Projects of Gansu Province(2023RCXM37)。
文摘Arid and semi-arid regions constitute approximately one-third of the total land area in China and are vulnerable to the effects of global climate change.Over the past century,a large number of studies have investigated regional climate change and its impacts.However,the conclusions are inconsistent due to differing research perspectives,and this has highlighted the urgent need to obtain systematic,scientific knowledge through review and synthesis.This study,based on a survey of all available literature,reviews the evolution of regional climate change and its effects in the arid and semi-arid regions of China over the last century.The present review examines three aspects of the surveyed previous studies:data,methods,and subjects,and then summarizes essential scientific findings into four subject areas:the origin and expansion of arid and semi-arid regions,the characteristics of climate change in these areas,the drivers of climate change in arid and semi-arid zones,and the consequences of climate change in such environments.Finally,six key directions for future research on climate change and its effects on the arid and semi-arid regions of China are proposed.
基金supported by the National Natural Science Foundation of China(Grant No.42088101)and the Energy Foundation,China。
文摘Addressing climate change and air pollution exhibits strong synergy,and the Chinese government is actively promoting the integrated management of these two issues.Since 2019,the China Clean Air Policy Partnership has released annual reports on China's progress in climate and air pollution governance.These reports track and analyze the challenges and propose solutions for China's pursuit of carbon neutrality and clean air by developing and monitoring key indicators across five areas.This report is the fourth annual report.Building on previous research,it further refines the collaborative governance monitoring indicator system,including the addition of climate change and extreme weather,atmospheric greenhouse gases,and enhanced efficiency of pollution removal technologies.The report includes the following components:(1)an analysis of the interactions between air pollution and climate change;(2)a discussion of governance systems and practices,with an emphasis on policy implementation and local experiences;(3)coverage of structural changes and emission reduction technologies,including energy and industrial transitions,transportation,low-carbon buildings,carbon capture and storage,and power systems;(4)an overview of atmospheric dynamics and emission pathways,examining emission drivers and offering insights for future coordinated governance;and(5)an evaluation of the health impacts and benefits of joint actions.These efforts underscore China's commitment to integrated control,resulting in slowed carbon emission growth,improved air quality,and enhanced health benefits.
