老年人痴呆或认知障碍多由一种以上年龄相关的常见脑部疾病所致。阿尔茨海默病(Alzheimer's disease,AD)是其中最常见的神经变性疾病,且是全球前10位死因中唯一无法治愈或缺乏长期对症疗效的疾病,给个人、家庭和全球经济都带来了巨...老年人痴呆或认知障碍多由一种以上年龄相关的常见脑部疾病所致。阿尔茨海默病(Alzheimer's disease,AD)是其中最常见的神经变性疾病,且是全球前10位死因中唯一无法治愈或缺乏长期对症疗效的疾病,给个人、家庭和全球经济都带来了巨大的负担。早期及时发现和干预是对抗AD的最佳策略。在过去的30年中,许多研究都提出了降低痴呆风险的方法,2020年《柳叶刀》杂志的痴呆预防报告已阐明通过应对风险因素可以预防或延缓超过40%的痴呆。然而,目前全球医疗体系尚未具备早期或及时发现AD的足够能力。最近的一项研究发现,只有不到10%的轻度认知障碍(mild cognitive impairment,MCI)是在初级医疗机构中诊断出来的。近来,抗淀粉样蛋白β(Amyloid beta,Aβ)抗体药物lecanemab和donanemab被批准上市用于早期AD治疗,以及30年的随访研究证明改善风险因素显著减少AD痴呆的发病率并延长了寿命,使得人们对AD早期识别的关注迅速增加。阿尔茨海默病防治协会(China Association for Alzheimer's Disease,CAAD)认识到居家早期和及时发现AD的重要性,并成立了一个由协会成员、临床医生和研究人员组成的全球AD多领域专家团队,就以下目标达成共识:①为个人、家庭、社区、协会和组织提供专家指导意见;②介绍用于认知障碍和痴呆居家筛查的数字工具和可用资源,并为AD高危人群或疑似患者制定下一步应对策略;③讨论现有可用或将来可能的居家筛查适宜AD生物标志物;④为未来的改进和全球应用建立可行性框架。专家组对于当前可用的证据、工具和资源进行综述,并进一步考量其在AD居家筛查中的价值。展开更多
Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is k...Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is known about the long-term stability of these biomarker proteins in plasma samples stored at-80°C.We aimed to explore how storage time would affect the diagnostic accuracy of these biomarkers using a large cohort.Plasma samples from 229 cognitively unimpaired individuals,encompassing healthy controls and those experiencing subjective cognitive decline,as well as 99 patients with cognitive impairment,comprising those with mild cognitive impairment and dementia,were acquired from the Sino Longitudinal Study on Cognitive Decline project.These samples were stored at-80°C for up to 6 years before being used in this study.Our results showed that plasma levels of Aβ42,Aβ40,neurofilament light chain,and glial fibrillary acidic protein were not significantly correlated with sample storage time.However,the level of total tau showed a negative correlation with sample storage time.Notably,in individuals without cognitive impairment,plasma levels of total protein and tau phosphorylated protein threonine 181(p-tau181)also showed a negative correlation with sample storage time.This was not observed in individuals with cognitive impairment.Consequently,we speculate that the diagnostic accuracy of plasma p-tau181 and the p-tau181 to total tau ratio may be influenced by sample storage time.Therefore,caution is advised when using these plasma biomarkers for the identification of neurodegenerative diseases,such as Alzheimer's disease.Furthermore,in cohort studies,it is important to consider the impact of storage time on the overall results.展开更多
In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three...In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three simulations were conducted with a 25-km grid spacing for the period 1980–2014.The first simulation(WRF_ERA5)was driven by the European Centre for Medium-Range Weather Forecasts Reanalysis 5(ERA5)dataset and served as the validation dataset.The original GCM dataset(MPI-ESM1-2-HR model)was used to drive the second simulation(WRF_GCM),while the third simulation(WRF_GCMbc)was driven by the bias-corrected GCM dataset.The bias-corrected GCM data has an ERA5-based mean and interannual variance and long-term trends derived from the ensemble mean of 18 CMIP6 models.Results demonstrate that the WRF_GCMbc significantly reduced the root-mean-square errors(RMSEs)of the climatological mean of downscaled variables,including temperature,precipitation,snow,wind,relative humidity,and planetary boundary layer height by 50%–90%compared to the WRF_GCM.Similarly,the RMSEs of interannual-tointerdecadal variances of downscaled variables were reduced by 30%–60%.Furthermore,the WRF_GCMbc better captured the annual cycle of the monsoon circulation and intraseasonal and day-to-day variabilities.The leading empirical orthogonal function(EOF)shows a monopole precipitation mode in the WRF_GCM.In contrast,the WRF_GCMbc successfully reproduced the observed tri-pole mode of summer precipitation over eastern China.This improvement could be attributed to a better-simulated location of the western North Pacific subtropical high in the WRF_GCMbc after GCM bias correction.展开更多
Half-integer microwave induced steps(Shapiro steps)have been observed in many different Josephson junction systems,which have attracted a lot of attention because they signify the deviation of current phase relation(C...Half-integer microwave induced steps(Shapiro steps)have been observed in many different Josephson junction systems,which have attracted a lot of attention because they signify the deviation of current phase relation(CPR)and uncover many unconventional physical properties.In this article,we first report the discovery of half-integer Shapiro steps in MgB_(2)focused He ion beam(He-FIB)Josephson junctions.The half-integer steps'dependence on microwave frequency,temperature,microwave power,and magnetic field is also analyzed.We find that the existence of half-integer steps can be controlled by the magnetic field periodically,which is similar to that of high temperature superconductor(HTS)grain boundary junctions,and the similarity of the microstructures between gain boundary junctions and He-FIB junctions is discussed.As a consequence,we mainly attribute the physical origin of half-integer steps in MgB_(2)He-FIB junctions to the model that a He-FIB junction is analogous to a parallel junctions'array.Our results show that He-FIB technology is a promising platform for researching CPR in junctions made of different superconductors.展开更多
Understanding the correlation between the fundamental descriptors and catalytic performance is meaningful to guide the design of high-performance electrochemical catalysts.However,exploring key factors that affect cat...Understanding the correlation between the fundamental descriptors and catalytic performance is meaningful to guide the design of high-performance electrochemical catalysts.However,exploring key factors that affect catalytic performance in the vast catalyst space remains challenging for people.Herein,to accurately identify the factors that affect the performance of N2 reduction,we apply interpretable machine learning(ML)to analyze high-throughput screening results,which is also suited to other surface reactions in catalysis.To expound on the paradigm,33 promising catalysts are screened from 168 carbon-supported candidates,specifically single-atom catalysts(SACs)supported by a BC_(3)monolayer(TM@V_(B/C)-N_(n)=_(0-3)-BC_(3))via high-throughput screening.Subsequently,the hybrid sampling method and XGBoost model are selected to classify eligible and non-eligible catalysts.Through feature interpretation using Shapley Additive Explanations(SHAP)analysis,two crucial features,that is,the number of valence electrons(N_(v))and nitrogen substitution(N_(n)),are screened out.Combining SHAP analysis and electronic structure calculations,the synergistic effect between an active center with low valence electron numbers and reasonable C-N coordination(a medium fraction of nitrogen substitution)can exhibit high catalytic performance.Finally,six superior catalysts with a limiting potential lower than-0.4 V are predicted.Our workflow offers a rational approach to obtaining key information on catalytic performance from high-throughput screening results to design efficient catalysts that can be applied to other materials and reactions.展开更多
AIM:To explore the dynamic changes of prion protein (PrPc) in the process of gastric cancer drug resistance and the role of PrPc expression in the prognosis of gastric cancer patients receiving chemotherapy.METHODS:A ...AIM:To explore the dynamic changes of prion protein (PrPc) in the process of gastric cancer drug resistance and the role of PrPc expression in the prognosis of gastric cancer patients receiving chemotherapy.METHODS:A series of gastric cancer cell lines resistant to different concentrations of adriamycin was established,and the expression of PrPc,Bcl-2 and Bax was detected in these cells.Apoptosis was determined using Annexin V staining.Western blotting and immunohisto-chemistry were performed to detect the expression of PrPc in patients receiving chemotherapy and to explore the role of PrPc expression in predicting the chemosensitivity and the outcome of gastric cancer patients receiving chemotherapy.Follow-up was performed for 2 years.RESULTS:PrPc expression was increased with the increase in drug resistance.Bcl-2,together with PrPc,increased the level of anti-apoptosis of cancer cells.Increased PrPc expression predicted the enhanced level of anti-apoptosis and resistance to anticancer drugs.PrPc expression could be used as a marker for predicting the efficacy of chemotherapy and the prognosis of gastric cancer.Increased PrPc expression predicted both poor chemosensitivity and a low 2-year survival rate.Contrarily,low PrPc expression predicted favorable chemosensitivity and a relatively high 2-year survival rate.CONCLUSION:PrPc expression is associated with histological types and differentiation of gastric cancer cells;The PrPc expression level might be a valuable marker in predicting the efficacy of chemotherapy and the prognosis of gastric cancer patients receiving chemotherapy.展开更多
The stability and chaotic vibrations of a pipe conveying fluid with both ends fixed, excited by the harmonic motion of its supporting base in a direction normal to the pipe span, were investigated with the aid of mode...The stability and chaotic vibrations of a pipe conveying fluid with both ends fixed, excited by the harmonic motion of its supporting base in a direction normal to the pipe span, were investigated with the aid of modern numerical techniques,involving the phase portrait,Lyapunov exponent and Poincare map tc. The nonlinear differential equations of motion of the system were derived by considering the additional axial force due to the lateral motion of the pipe. Attention was concentrated on the effect of forcing frequency and flow velocity on the dynamics of the system. It is shown that chaotic motions can occur in this system in a certain region of parameter space,and it is also found that three types of routes to chaos exist in the system:(i)period doubling bifurcations;(ii)quasi periodic motions;and (iii)intermittent chaos.展开更多
BACKGROUND Higher intraocular pressure(IOP)is a major risk factor for developing glaucoma,and the leading cause of irreversible blindness worldwide.High altitude(HA)may be involved in IOP,but the reported results were...BACKGROUND Higher intraocular pressure(IOP)is a major risk factor for developing glaucoma,and the leading cause of irreversible blindness worldwide.High altitude(HA)may be involved in IOP,but the reported results were conflicting.Ascent to HA directly by plane from low altitude regions is an acute,effortless exposure.However,the effects of such exposure to different altitudes on IOP have rarely been reported.AIM To investigate changes in IOP after rapid effortless exposure to HA in stages and compare it with systemic parameters.METHODS Fifty-eight healthy subjects(116 eyes)were divided into three groups:17 lowaltitude(LA)residents[44 m above sea level(ASL)],22 HA residents(2261 m ASL)and 19 very HA(VHA)residents(3750 m ASL).The LA group flew to HA first.Three days later,they flew with the HA group to VHA where both groups stayed for 2 d.Then,the LA group flew back to HA and stayed for 1 d before flying back to 44 m.IOP,oxygen saturation(SpO2)and pulse rate were measured.The linear mixed model was used to compare repeated measurements.RESULTS IOP in the LA group significantly decreased from 18.41±2.40 mmHg at 44 m to 13.60±3.68 mmHg at 2261 m ASL(P<0.001),and then to 11.85±2.48 mmHg at 3750 m ASL(P=0.036 compared to IOP at 2261 m ASL)and partially recovered to 13.47±2.57 mmHg upon return to 44 m.IOP in the LA group at HA and VHA was comparable to that in the local residents(12.2±2.4 mmHg for HA,11.5±1.8 mmHg for VHA).IOP was positively associated with SpO2 while negatively associated with pulse rate.CONCLUSION IOP in the LA group gradually reduced as altitude elevated in stages and became comparable to IOP in local residents.Hypoxia may be associated with IOP,which deserves further study.展开更多
This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins(SCER). The effects of the mass ratio of methanol to acidified ...This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins(SCER). The effects of the mass ratio of methanol to acidified oil,reaction temperature,and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids(FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0,reaction temperature of 65.0 °C,catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including G,S and H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.展开更多
Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off,which is hindering their wider applications.In this study,we propose a gradient heterogeneous grain(GHG)structure for evading...Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off,which is hindering their wider applications.In this study,we propose a gradient heterogeneous grain(GHG)structure for evading this trade-off dilemma and ultrasonic severe surface rolling is attempted to construct this novel structure in ZE41 Mg alloy.Here,the GHG structure combine the benefits of gradient structure and heterogeneous grain structure and introduce large microstructural heterogeneities.Compared to the coarse-grain and heterogeneous-grain structured alloys,the GHG structured one exhibits dramatical enhancement in strength,ductility,and strain hardening capability.To the best of our knowledge,its strength becomes much higher than that of common ZE41 Mg alloys at no reduction in ductility.These unique mechanical properties stem from not only the individual contribution of the heterogeneous structure components including the fine/ultrafine grains and deformed coarse grains but also their synergistic effect via hetero-deformation induced strengthening and hardening effects.In summary,our study provides a feasible way to develop new Mg alloys with high strength and good ductility.展开更多
The understanding of soliton dynamics promotes the development of ultrafast laser technology. High-energy purequartic solitons(PQSs) have gradually become a hotspot in recent years. Herein, we numerically study the in...The understanding of soliton dynamics promotes the development of ultrafast laser technology. High-energy purequartic solitons(PQSs) have gradually become a hotspot in recent years. Herein, we numerically study the influence of the gain bandwidth, saturation power, small-signal gain, and output coupler on PQS dynamics in passively mode-locked fiber lasers. The results show that the above four parameters can affect PQS dynamics. Pulsating PQSs occur as we alter the other three parameters when the gain bandwidth is 50 nm. Meanwhile, PQSs evolve from pulsating to erupting and then to splitting as the other three parameters are altered when the gain bandwidth is 10 nm, which can be attributed to the existence of the spectral filtering effect and intra-cavity fourth-order dispersion. These findings provide new insights into PQS dynamics in passively mode-locked fiber lasers.展开更多
This study developed a novel MnFe-LDH/PMS/O3 three-phase catalytic system to degrade the organic dye RhB, which was used to address the drawbacks of persulfate oxidation and ozonation techniques. The structure, ionic ...This study developed a novel MnFe-LDH/PMS/O3 three-phase catalytic system to degrade the organic dye RhB, which was used to address the drawbacks of persulfate oxidation and ozonation techniques. The structure, ionic and elemental composition, specific surface area, and magnetic properties of the LDHs were investigated using a variety of physicochemical characterization tools. The results showed that MnFe-LDH had a large specific surface area, a rich crystalline phase composition, and a functional group structure. The RhB degradation rate of MnFe-LDH/PMS/O3 was 0.34 min−1, which was much higher than that of other comparative systems. RhB could be completely degraded in 10 min after optimization and had a significant effect on TOC removal. The system was found to be effective over a wide pH range. Common anions were largely unaffected and humic acid acted as an inhibitor. At the same time, the system had generally effective degradation performance for different dyes. Combined with quenching experiments and EPR, it was found that SO4•−, •OH, O_(2)•−, and 1O_(2) all participated in the reaction, and •OH contributed more. The degradation pathway of RhB was derived by LC-MS, and the T.E.S.T. evaluation found that the toxicity of the intermediate product was significantly reduced. Finally, the stability and availability of LDHs were verified using cycling experiments and metal ion leaching. This work provides a theoretical basis and data support for the synergistic catalysis of PMS/O3 and the deep treatment of dye wastewater.展开更多
The steep sub-threshold swing of a tunneling field-effect transistor(TFET)makes it one of the best candidates for lowpower nanometer devices.However,the low driving capability of TFETs prevents their application in in...The steep sub-threshold swing of a tunneling field-effect transistor(TFET)makes it one of the best candidates for lowpower nanometer devices.However,the low driving capability of TFETs prevents their application in integrated circuits.In this study,an innovative gate-all-around(GAA)TFET,which represents a negative capacitance GAA gate-to-source overlap TFET(NCGAA-SOL-TFET),is proposed to increase the driving current.The proposed NCGAA-SOL-TFET is developed based on technology computer-aided design(TCAD)simulations.The proposed structure can solve the problem of the insufficient driving capability of conventional TFETs and is suitable for sub-3-nm nodes.In addition,due to the negative capacitance effect,the surface potential of the channel can be amplified,thus enhancing the driving current.The gateto-source overlap(SOL)technique is used for the first time in an NCGAA-TFET to increase the band-to-band tunneling rate and tunneling area at the silicon-germanium heterojunction.By optimizing the design of the proposed structure via adjusting the SOL length and the ferroelectric layer thickness,a sufficiently large on-state current of 17.20μA can be achieved and the threshold voltage can be reduced to 0.31 V with a sub-threshold swing of 44.98 mV/decade.Finally,the proposed NCGAA-SOL-TFET can overcome the Boltzmann limit-related problem,achieving a driving current that is comparable to that of the traditional complementary metal-oxide semiconductor devices.展开更多
Rapid and accurate determination of compressor characteristic maps is essential for the initial design of centrifugal compressors in aircraft power systems. The accuracy of existing methodologies, which rely on combin...Rapid and accurate determination of compressor characteristic maps is essential for the initial design of centrifugal compressors in aircraft power systems. The accuracy of existing methodologies, which rely on combinations of loss models, varies significantly depending on the compressor's geometry and operational range. This variance necessitates substantial experimental or Computational Fluid Dynamics(CFD) data for coefficient calibration. To address this challenge, this study presents an axisymmetric characteristic model for compressor performance assessment. This model incorporates the factors of blade angle, meridional passage area, and the radial deflection angle of meridional streamlines of the compressor. These factors are derived from fundamental aerodynamic equations encompassing mass, momentum, and energy conservation of the compressor. In contrast to conventional one-dimensional approaches, the proposed method reduces the number of loss coefficients and more effectively accounts for the impact of geometric alterations on centrifugal compressor properties. Furthermore, the model reduces dependence on experimental and CFD data. Efficacy of the model is validated using experimental data from four distinct types of centrifugal compressors. Correlation analysis reveals that the model's coefficients can be expressed as functions of the ratio of the Reynolds number to the impeller tip speed. This ratio serves as a characteristic parameter for the design and optimization of centrifugal compressors. Consequently, the proposed method offers an efficient and accurate means for the quick computation of centrifugal compressor characteristics. This is of great significance for improving the efficiency of centrifugal compressors and reducing energy consumption.展开更多
Evaluation of the efficacy of traditional Chinese medicines (TCMs) is an important prerequisite for discovering effective substances, lead compounds, and quality markers (Q markers). At present, there is an urgent nee...Evaluation of the efficacy of traditional Chinese medicines (TCMs) is an important prerequisite for discovering effective substances, lead compounds, and quality markers (Q markers). At present, there is an urgent need to develop a biological language that can act as abridge for the scientific elaboration of the efficacy of TCMs, and to further highlight the significant value of TCM. Chinese medicinal syndromes and formulae are two essential parts of TCM that directly relate to its efficacy. Syndromes and formulae have been taken as the research objects. The serum pharmacochemistry of the TCM approach with metabolomics were integrated to establish an innovative chinmedomics strategy, which is able to explore syndrome biomarkers and evaluate TCM efficacy in order to discover effective substances from TCMs. A great deal of concrete work in chinmedomics has already performed to bridge the gap between Chinese and Western medicine, and to provide a powerful approach to enhance the scientific value of TCM theory and clinical practice. This article summarizes the application of chinmedomics in identifying the candidate biomarkers of a syndrome and revealing the efficacy of the related formula. We also highlight the discovery of lead compounds and Q markers from TCMs.展开更多
文摘老年人痴呆或认知障碍多由一种以上年龄相关的常见脑部疾病所致。阿尔茨海默病(Alzheimer's disease,AD)是其中最常见的神经变性疾病,且是全球前10位死因中唯一无法治愈或缺乏长期对症疗效的疾病,给个人、家庭和全球经济都带来了巨大的负担。早期及时发现和干预是对抗AD的最佳策略。在过去的30年中,许多研究都提出了降低痴呆风险的方法,2020年《柳叶刀》杂志的痴呆预防报告已阐明通过应对风险因素可以预防或延缓超过40%的痴呆。然而,目前全球医疗体系尚未具备早期或及时发现AD的足够能力。最近的一项研究发现,只有不到10%的轻度认知障碍(mild cognitive impairment,MCI)是在初级医疗机构中诊断出来的。近来,抗淀粉样蛋白β(Amyloid beta,Aβ)抗体药物lecanemab和donanemab被批准上市用于早期AD治疗,以及30年的随访研究证明改善风险因素显著减少AD痴呆的发病率并延长了寿命,使得人们对AD早期识别的关注迅速增加。阿尔茨海默病防治协会(China Association for Alzheimer's Disease,CAAD)认识到居家早期和及时发现AD的重要性,并成立了一个由协会成员、临床医生和研究人员组成的全球AD多领域专家团队,就以下目标达成共识:①为个人、家庭、社区、协会和组织提供专家指导意见;②介绍用于认知障碍和痴呆居家筛查的数字工具和可用资源,并为AD高危人群或疑似患者制定下一步应对策略;③讨论现有可用或将来可能的居家筛查适宜AD生物标志物;④为未来的改进和全球应用建立可行性框架。专家组对于当前可用的证据、工具和资源进行综述,并进一步考量其在AD居家筛查中的价值。
基金supported by the National Key Research&Development Program of China,Nos.2021YFC2501205(to YC),2022YFC24069004(to JL)the STI2030-Major Project,Nos.2021ZD0201101(to YC),2022ZD0211800(to YH)+2 种基金the National Natural Science Foundation of China(Major International Joint Research Project),No.82020108013(to YH)the Sino-German Center for Research Promotion,No.M-0759(to YH)a grant from Beijing Municipal Science&Technology Commission(Beijing Brain Initiative),No.Z201100005520018(to JL)。
文摘Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is known about the long-term stability of these biomarker proteins in plasma samples stored at-80°C.We aimed to explore how storage time would affect the diagnostic accuracy of these biomarkers using a large cohort.Plasma samples from 229 cognitively unimpaired individuals,encompassing healthy controls and those experiencing subjective cognitive decline,as well as 99 patients with cognitive impairment,comprising those with mild cognitive impairment and dementia,were acquired from the Sino Longitudinal Study on Cognitive Decline project.These samples were stored at-80°C for up to 6 years before being used in this study.Our results showed that plasma levels of Aβ42,Aβ40,neurofilament light chain,and glial fibrillary acidic protein were not significantly correlated with sample storage time.However,the level of total tau showed a negative correlation with sample storage time.Notably,in individuals without cognitive impairment,plasma levels of total protein and tau phosphorylated protein threonine 181(p-tau181)also showed a negative correlation with sample storage time.This was not observed in individuals with cognitive impairment.Consequently,we speculate that the diagnostic accuracy of plasma p-tau181 and the p-tau181 to total tau ratio may be influenced by sample storage time.Therefore,caution is advised when using these plasma biomarkers for the identification of neurodegenerative diseases,such as Alzheimer's disease.Furthermore,in cohort studies,it is important to consider the impact of storage time on the overall results.
基金supported jointly by the National Natural Science Foundation of China (Grant No.42075170)the National Key Research and Development Program of China (2022YFF0802503)+2 种基金the Jiangsu Collaborative Innovation Center for Climate Changea Chinese University Direct Grant(Grant No. 4053331)supported by the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulator Facility”(EarthLab)
文摘In this study,we aim to assess dynamical downscaling simulations by utilizing a novel bias-corrected global climate model(GCM)data to drive a regional climate model(RCM)over the Asia-western North Pacific region.Three simulations were conducted with a 25-km grid spacing for the period 1980–2014.The first simulation(WRF_ERA5)was driven by the European Centre for Medium-Range Weather Forecasts Reanalysis 5(ERA5)dataset and served as the validation dataset.The original GCM dataset(MPI-ESM1-2-HR model)was used to drive the second simulation(WRF_GCM),while the third simulation(WRF_GCMbc)was driven by the bias-corrected GCM dataset.The bias-corrected GCM data has an ERA5-based mean and interannual variance and long-term trends derived from the ensemble mean of 18 CMIP6 models.Results demonstrate that the WRF_GCMbc significantly reduced the root-mean-square errors(RMSEs)of the climatological mean of downscaled variables,including temperature,precipitation,snow,wind,relative humidity,and planetary boundary layer height by 50%–90%compared to the WRF_GCM.Similarly,the RMSEs of interannual-tointerdecadal variances of downscaled variables were reduced by 30%–60%.Furthermore,the WRF_GCMbc better captured the annual cycle of the monsoon circulation and intraseasonal and day-to-day variabilities.The leading empirical orthogonal function(EOF)shows a monopole precipitation mode in the WRF_GCM.In contrast,the WRF_GCMbc successfully reproduced the observed tri-pole mode of summer precipitation over eastern China.This improvement could be attributed to a better-simulated location of the western North Pacific subtropical high in the WRF_GCMbc after GCM bias correction.
基金supported by the National Natural Science Foundation of China (Grant No.12104016)the National Key Research and Development Program of China (Grant No.2020YFF01014706)。
文摘Half-integer microwave induced steps(Shapiro steps)have been observed in many different Josephson junction systems,which have attracted a lot of attention because they signify the deviation of current phase relation(CPR)and uncover many unconventional physical properties.In this article,we first report the discovery of half-integer Shapiro steps in MgB_(2)focused He ion beam(He-FIB)Josephson junctions.The half-integer steps'dependence on microwave frequency,temperature,microwave power,and magnetic field is also analyzed.We find that the existence of half-integer steps can be controlled by the magnetic field periodically,which is similar to that of high temperature superconductor(HTS)grain boundary junctions,and the similarity of the microstructures between gain boundary junctions and He-FIB junctions is discussed.As a consequence,we mainly attribute the physical origin of half-integer steps in MgB_(2)He-FIB junctions to the model that a He-FIB junction is analogous to a parallel junctions'array.Our results show that He-FIB technology is a promising platform for researching CPR in junctions made of different superconductors.
基金supported by the National Key R&D Program of China(2022YFA1503103)the National Natural Science Foundation of China(22033002,92261112,22203046)+2 种基金the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(Grant No.NY221128)the Six Talent Peaks Project in Jiangsu Province(XCL-104)the open research fund of Key Laboratory of Quantum Materials and Devices(Southeast University)
文摘Understanding the correlation between the fundamental descriptors and catalytic performance is meaningful to guide the design of high-performance electrochemical catalysts.However,exploring key factors that affect catalytic performance in the vast catalyst space remains challenging for people.Herein,to accurately identify the factors that affect the performance of N2 reduction,we apply interpretable machine learning(ML)to analyze high-throughput screening results,which is also suited to other surface reactions in catalysis.To expound on the paradigm,33 promising catalysts are screened from 168 carbon-supported candidates,specifically single-atom catalysts(SACs)supported by a BC_(3)monolayer(TM@V_(B/C)-N_(n)=_(0-3)-BC_(3))via high-throughput screening.Subsequently,the hybrid sampling method and XGBoost model are selected to classify eligible and non-eligible catalysts.Through feature interpretation using Shapley Additive Explanations(SHAP)analysis,two crucial features,that is,the number of valence electrons(N_(v))and nitrogen substitution(N_(n)),are screened out.Combining SHAP analysis and electronic structure calculations,the synergistic effect between an active center with low valence electron numbers and reasonable C-N coordination(a medium fraction of nitrogen substitution)can exhibit high catalytic performance.Finally,six superior catalysts with a limiting potential lower than-0.4 V are predicted.Our workflow offers a rational approach to obtaining key information on catalytic performance from high-throughput screening results to design efficient catalysts that can be applied to other materials and reactions.
基金Supported by National Natural Science Foundation of China, No. 30672063China Postdoctoral Science Foundation Funded Project,No. 20080431404China Postdoctoral Special Fund,No. 200801038
文摘AIM:To explore the dynamic changes of prion protein (PrPc) in the process of gastric cancer drug resistance and the role of PrPc expression in the prognosis of gastric cancer patients receiving chemotherapy.METHODS:A series of gastric cancer cell lines resistant to different concentrations of adriamycin was established,and the expression of PrPc,Bcl-2 and Bax was detected in these cells.Apoptosis was determined using Annexin V staining.Western blotting and immunohisto-chemistry were performed to detect the expression of PrPc in patients receiving chemotherapy and to explore the role of PrPc expression in predicting the chemosensitivity and the outcome of gastric cancer patients receiving chemotherapy.Follow-up was performed for 2 years.RESULTS:PrPc expression was increased with the increase in drug resistance.Bcl-2,together with PrPc,increased the level of anti-apoptosis of cancer cells.Increased PrPc expression predicted the enhanced level of anti-apoptosis and resistance to anticancer drugs.PrPc expression could be used as a marker for predicting the efficacy of chemotherapy and the prognosis of gastric cancer.Increased PrPc expression predicted both poor chemosensitivity and a low 2-year survival rate.Contrarily,low PrPc expression predicted favorable chemosensitivity and a relatively high 2-year survival rate.CONCLUSION:PrPc expression is associated with histological types and differentiation of gastric cancer cells;The PrPc expression level might be a valuable marker in predicting the efficacy of chemotherapy and the prognosis of gastric cancer patients receiving chemotherapy.
基金Supported by the Science Foundation of Liaoning Province Government!( 96 2 1 2 9)
文摘The stability and chaotic vibrations of a pipe conveying fluid with both ends fixed, excited by the harmonic motion of its supporting base in a direction normal to the pipe span, were investigated with the aid of modern numerical techniques,involving the phase portrait,Lyapunov exponent and Poincare map tc. The nonlinear differential equations of motion of the system were derived by considering the additional axial force due to the lateral motion of the pipe. Attention was concentrated on the effect of forcing frequency and flow velocity on the dynamics of the system. It is shown that chaotic motions can occur in this system in a certain region of parameter space,and it is also found that three types of routes to chaos exist in the system:(i)period doubling bifurcations;(ii)quasi periodic motions;and (iii)intermittent chaos.
基金Supported by the National Natural Science Foundation of China,No.81730027Beijing Natural Science Foundation,No.7162037The Capital Health Research and Development of Special Foundation,No.ZYLX201501
文摘BACKGROUND Higher intraocular pressure(IOP)is a major risk factor for developing glaucoma,and the leading cause of irreversible blindness worldwide.High altitude(HA)may be involved in IOP,but the reported results were conflicting.Ascent to HA directly by plane from low altitude regions is an acute,effortless exposure.However,the effects of such exposure to different altitudes on IOP have rarely been reported.AIM To investigate changes in IOP after rapid effortless exposure to HA in stages and compare it with systemic parameters.METHODS Fifty-eight healthy subjects(116 eyes)were divided into three groups:17 lowaltitude(LA)residents[44 m above sea level(ASL)],22 HA residents(2261 m ASL)and 19 very HA(VHA)residents(3750 m ASL).The LA group flew to HA first.Three days later,they flew with the HA group to VHA where both groups stayed for 2 d.Then,the LA group flew back to HA and stayed for 1 d before flying back to 44 m.IOP,oxygen saturation(SpO2)and pulse rate were measured.The linear mixed model was used to compare repeated measurements.RESULTS IOP in the LA group significantly decreased from 18.41±2.40 mmHg at 44 m to 13.60±3.68 mmHg at 2261 m ASL(P<0.001),and then to 11.85±2.48 mmHg at 3750 m ASL(P=0.036 compared to IOP at 2261 m ASL)and partially recovered to 13.47±2.57 mmHg upon return to 44 m.IOP in the LA group at HA and VHA was comparable to that in the local residents(12.2±2.4 mmHg for HA,11.5±1.8 mmHg for VHA).IOP was positively associated with SpO2 while negatively associated with pulse rate.CONCLUSION IOP in the LA group gradually reduced as altitude elevated in stages and became comparable to IOP in local residents.Hypoxia may be associated with IOP,which deserves further study.
基金support from the Natural Science Foundation of Shandong Province (Grant no.ZR2013BL010)the Research Excellence Award of Shandong University of Technology and the Zibo Technology Research and Development Program of China (Grant no.2013GG04110)
文摘This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins(SCER). The effects of the mass ratio of methanol to acidified oil,reaction temperature,and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids(FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0,reaction temperature of 65.0 °C,catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including G,S and H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.
基金This work was supported by key projects of National Natural Science Foundation of China(No.81830110)Heilongjiang Province key research and development plan(No.2022ZX02C04).
基金the financial support of the National Natural Science Foundation of China(Grant No.51971088,No.U1910212)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off,which is hindering their wider applications.In this study,we propose a gradient heterogeneous grain(GHG)structure for evading this trade-off dilemma and ultrasonic severe surface rolling is attempted to construct this novel structure in ZE41 Mg alloy.Here,the GHG structure combine the benefits of gradient structure and heterogeneous grain structure and introduce large microstructural heterogeneities.Compared to the coarse-grain and heterogeneous-grain structured alloys,the GHG structured one exhibits dramatical enhancement in strength,ductility,and strain hardening capability.To the best of our knowledge,its strength becomes much higher than that of common ZE41 Mg alloys at no reduction in ductility.These unique mechanical properties stem from not only the individual contribution of the heterogeneous structure components including the fine/ultrafine grains and deformed coarse grains but also their synergistic effect via hetero-deformation induced strengthening and hardening effects.In summary,our study provides a feasible way to develop new Mg alloys with high strength and good ductility.
基金the financial support from Science and Technology Project of the Jilin Provincial Department of Education (Grant No. JJKH20231171KJ)。
文摘The understanding of soliton dynamics promotes the development of ultrafast laser technology. High-energy purequartic solitons(PQSs) have gradually become a hotspot in recent years. Herein, we numerically study the influence of the gain bandwidth, saturation power, small-signal gain, and output coupler on PQS dynamics in passively mode-locked fiber lasers. The results show that the above four parameters can affect PQS dynamics. Pulsating PQSs occur as we alter the other three parameters when the gain bandwidth is 50 nm. Meanwhile, PQSs evolve from pulsating to erupting and then to splitting as the other three parameters are altered when the gain bandwidth is 10 nm, which can be attributed to the existence of the spectral filtering effect and intra-cavity fourth-order dispersion. These findings provide new insights into PQS dynamics in passively mode-locked fiber lasers.
基金supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region(China)(No.2022D01C733)Yili Normal University’s Special Project on Enhancing Comprehensive Strength of Disciplines(China)(No.22XKZZ03)Research and Innovation Team Cultivation Program of Yili Normal University(China)(No.CXZK2021004).
文摘This study developed a novel MnFe-LDH/PMS/O3 three-phase catalytic system to degrade the organic dye RhB, which was used to address the drawbacks of persulfate oxidation and ozonation techniques. The structure, ionic and elemental composition, specific surface area, and magnetic properties of the LDHs were investigated using a variety of physicochemical characterization tools. The results showed that MnFe-LDH had a large specific surface area, a rich crystalline phase composition, and a functional group structure. The RhB degradation rate of MnFe-LDH/PMS/O3 was 0.34 min−1, which was much higher than that of other comparative systems. RhB could be completely degraded in 10 min after optimization and had a significant effect on TOC removal. The system was found to be effective over a wide pH range. Common anions were largely unaffected and humic acid acted as an inhibitor. At the same time, the system had generally effective degradation performance for different dyes. Combined with quenching experiments and EPR, it was found that SO4•−, •OH, O_(2)•−, and 1O_(2) all participated in the reaction, and •OH contributed more. The degradation pathway of RhB was derived by LC-MS, and the T.E.S.T. evaluation found that the toxicity of the intermediate product was significantly reduced. Finally, the stability and availability of LDHs were verified using cycling experiments and metal ion leaching. This work provides a theoretical basis and data support for the synergistic catalysis of PMS/O3 and the deep treatment of dye wastewater.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY22F040001)the National Natural Science Foundation of China(Grant No.62071160)the Graduate Scientific Research Foundation of Hangzhou Dianzi University。
文摘The steep sub-threshold swing of a tunneling field-effect transistor(TFET)makes it one of the best candidates for lowpower nanometer devices.However,the low driving capability of TFETs prevents their application in integrated circuits.In this study,an innovative gate-all-around(GAA)TFET,which represents a negative capacitance GAA gate-to-source overlap TFET(NCGAA-SOL-TFET),is proposed to increase the driving current.The proposed NCGAA-SOL-TFET is developed based on technology computer-aided design(TCAD)simulations.The proposed structure can solve the problem of the insufficient driving capability of conventional TFETs and is suitable for sub-3-nm nodes.In addition,due to the negative capacitance effect,the surface potential of the channel can be amplified,thus enhancing the driving current.The gateto-source overlap(SOL)technique is used for the first time in an NCGAA-TFET to increase the band-to-band tunneling rate and tunneling area at the silicon-germanium heterojunction.By optimizing the design of the proposed structure via adjusting the SOL length and the ferroelectric layer thickness,a sufficiently large on-state current of 17.20μA can be achieved and the threshold voltage can be reduced to 0.31 V with a sub-threshold swing of 44.98 mV/decade.Finally,the proposed NCGAA-SOL-TFET can overcome the Boltzmann limit-related problem,achieving a driving current that is comparable to that of the traditional complementary metal-oxide semiconductor devices.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No. 2022A1515110007)the Natural Science Foundation of Guangdong Province, China (No. 2023A1515012869)the GDAS’ Project of Science and Technology Development, China (No. 2021GDASYL-20210103090)。
文摘Rapid and accurate determination of compressor characteristic maps is essential for the initial design of centrifugal compressors in aircraft power systems. The accuracy of existing methodologies, which rely on combinations of loss models, varies significantly depending on the compressor's geometry and operational range. This variance necessitates substantial experimental or Computational Fluid Dynamics(CFD) data for coefficient calibration. To address this challenge, this study presents an axisymmetric characteristic model for compressor performance assessment. This model incorporates the factors of blade angle, meridional passage area, and the radial deflection angle of meridional streamlines of the compressor. These factors are derived from fundamental aerodynamic equations encompassing mass, momentum, and energy conservation of the compressor. In contrast to conventional one-dimensional approaches, the proposed method reduces the number of loss coefficients and more effectively accounts for the impact of geometric alterations on centrifugal compressor properties. Furthermore, the model reduces dependence on experimental and CFD data. Efficacy of the model is validated using experimental data from four distinct types of centrifugal compressors. Correlation analysis reveals that the model's coefficients can be expressed as functions of the ratio of the Reynolds number to the impeller tip speed. This ratio serves as a characteristic parameter for the design and optimization of centrifugal compressors. Consequently, the proposed method offers an efficient and accurate means for the quick computation of centrifugal compressor characteristics. This is of great significance for improving the efficiency of centrifugal compressors and reducing energy consumption.
基金grants from the Key Program of National Natural Science Foundation of China (81830110, 81430093, 81373930, 81673586, 81302905, and 81503386)the National Key Subject of Drug Innovation (2015ZX09101043-005 and 2015ZX09101043-011)+2 种基金the TCM State Administration Subject of Public Welfare (2015468004)the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (UNPYSCT-2015118)the Young Talent Lift Engineering Project of China Association of Traditional Chinese Medicine (QNRC2-B06).
文摘Evaluation of the efficacy of traditional Chinese medicines (TCMs) is an important prerequisite for discovering effective substances, lead compounds, and quality markers (Q markers). At present, there is an urgent need to develop a biological language that can act as abridge for the scientific elaboration of the efficacy of TCMs, and to further highlight the significant value of TCM. Chinese medicinal syndromes and formulae are two essential parts of TCM that directly relate to its efficacy. Syndromes and formulae have been taken as the research objects. The serum pharmacochemistry of the TCM approach with metabolomics were integrated to establish an innovative chinmedomics strategy, which is able to explore syndrome biomarkers and evaluate TCM efficacy in order to discover effective substances from TCMs. A great deal of concrete work in chinmedomics has already performed to bridge the gap between Chinese and Western medicine, and to provide a powerful approach to enhance the scientific value of TCM theory and clinical practice. This article summarizes the application of chinmedomics in identifying the candidate biomarkers of a syndrome and revealing the efficacy of the related formula. We also highlight the discovery of lead compounds and Q markers from TCMs.