The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple ...The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis strategy.The experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon material.The FeCo/SNC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E_(1/2)=0.8823 V)for ORR and a low overpotential at 10 mA cm^(-2)(E_(j=10)=299 mV)for OER.In addition,compared with Pt/C+RuO_(2) assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 mA h g_(zn)~(-1)),and ultra-stable cycle performance.These results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.展开更多
Objective:Accurate prognosis prediction is critical for individualized-therapy making of gastric cancer patients.We aimed to develop and test 6-month,1-,2-,3-,5-,and 10-year overall survival(OS)and cancer-specific sur...Objective:Accurate prognosis prediction is critical for individualized-therapy making of gastric cancer patients.We aimed to develop and test 6-month,1-,2-,3-,5-,and 10-year overall survival(OS)and cancer-specific survival(CSS)prediction models for gastric cancer patients following gastrectomy.Methods:We derived and tested Survival Quilts,a machine learning-based model,to develop 6-month,1-,2-,3-,5-,and 10-year OS and CSS prediction models.Gastrectomy patients in the development set(n=20,583)and the internal validation set(n=5,106)were recruited from the Surveillance,Epidemiology,and End Re-sults(SEER)database,while those in the external validation set(n=6,352)were recruited from the China National Cancer Center Gastric Cancer(NCCGC)database.Furthermore,we selected gastrectomy patients with-out neoadjuvant therapy as a subgroup to train and test the prognostic models in order to keep the accuracy of tumor-node-metastasis(TNM)stage.Prognostic performances of these OS and CSS models were assessed using the Concordance Index(C-index)and area under the curve(AUC)values.Results:The machine learning model had a consistently high accuracy in predicting 6-month,1-,2-,3-,5-,and 10-year OS in the SEER development set(C-index=0.861,0.832,0.789,0.766,0.740,and 0.709;AUC=0.784,0.828,0.840,0.849,0.869,and 0.902,respectively),SEER validation set(C-index=0.782,0.739,0.712,0.698,0.681,and 0.660;AUC=0.751,0.772,0.767,0.762,0.766,and 0.787,respectively),and NCCGC set(C-index=0.691,0.756,0.751,0.737,0.722,and 0.701;AUC=0.769,0.788,0.790,0.790,0.787,and 0.788,respectively).The model was able to predict 6-month,1-,2-,3-,5-,and 10-year CSS in the SEER development set(C-index=0.879,0.858,0.820,0.802,0.784,and 0.774;AUC=0.756,0.827,0.852,0.863,0.874,and 0.884,respectively)and SEER validation set(C-index=0.790,0.763,0.741,0.729,0.718,and 0.708;AUC=0.706,0.758,0.767,0.766,0.766,and 0.764,respectively).In multivariate analysis,the high-risk group with risk score output by 5-year OS model was proved to be a strong survival predictor both in the SEER development set(hazard ratio[HR]=14.59,95%confidence interval[CI]:1.872-2.774,P<0.001),SEER validation set(HR=2.28,95%CI:13.089-16.293,P<0.001),and NCCGC set(HR=1.98,95%CI:1.617-2.437,P<0.001).We further explored the prognostic value of risk score resulted 5-year CSS model of gastrectomy patients,and found that high-risk group remained as an independent CSS factor in the SEER development set(HR=12.81,95%CI:11.568-14.194,P<0.001)and SEER validation set(HR=1.61,95%CI:1.338-1.935,P<0.001).Conclusion:Survival Quilts could allow accurate prediction of 6-month,1-,2-,3-,5-,and 10-year OS and CSS in gastric cancer patients following gastrectomy.展开更多
Background:Although methionine(Met),the first-limiting dietary amino acid,has crucial roles in growth and regulation of lipid metabolism in ducks,mechanisms underlying are not well understood.Therefore,the objective w...Background:Although methionine(Met),the first-limiting dietary amino acid,has crucial roles in growth and regulation of lipid metabolism in ducks,mechanisms underlying are not well understood.Therefore,the objective was to use dietary Met deficiency to investigate the involvement of Met in lipid metabolism and fat accumulation of Pekin ducks.Methods:A total of 150 male Pekin ducks(15-d-old,558.5±4.4 g)were allocated into 5 groups(6 replicates with 5 birds each)and fed corn and soybean meal-based diets containing 0.28%,0.35%,0.43%,0.50%,and 0.58%Met,respectively,for 4 weeks.Met-deficient(Met-D,0.28%Met)and Met-adequate(Met-A,0.43%Met)groups were selected for subsequent molecular studies.Serum,liver,and abdominal fat samples were collected to assess the genes and proteins involved in lipid metabolism of Pekin ducks and hepatocytes were cultured in vivo for verification.Results:Dietary Met deficiency caused growth depression and excess fat deposition that were ameliorated by feeding diets with adequate Met.Serum triglyceride and non-esterified fatty acid concentrations increased(P<0.05),whereas serum concentrations of total cholesterol,low density lipoprotein cholesterol,total protein,and albumin decreased(P<0.05)in Met-D ducks compared to those in Met-A ducks.Based on hepatic proteomics analyses,dietary Met deficiency suppressed expression of key proteins related to fatty acid transport,fatty acid oxidation,tricarboxylic acid cycle,glycolysis/gluconeogenesis,ketogenesis,and electron transport chain;selected key proteins had similar expression patterns verified by qRT-PCR and Western blotting,which indicated these processes were likely impaired.In vitro verification with hepatocyte models confirmed albumin expression was diminished by Met deficiency.Additionally,in abdominal fat,dietary Met deficiency increased adipocyte diameter and area(P<0.05),and down-regulated(P<0.05)of lipolytic genes and proteins,suggesting Met deficiency may suppress lipolysis in adipocyte.Conclusion:Taken together,these data demonstrated that dietary Met deficiency in Pekin ducks resulted in stunted growth and excess fat deposition,which may be related to suppression of fatty acids transportation and hepatic catabolism.展开更多
Objective This study aimed to describe the current situation of knowledge,attitude,and practice(KAP)of chronic obstructive pulmonary disease(COPD)prevention among a high-risk population for COPD.Methods A cross-sectio...Objective This study aimed to describe the current situation of knowledge,attitude,and practice(KAP)of chronic obstructive pulmonary disease(COPD)prevention among a high-risk population for COPD.Methods A cross-sectional survey was conducted.A total of 241 participants at risk of COPD were selected who visited the respiratory outpatient department of a Class A tertiary hospital in Chongqing,China from January to December 2021.A self-developed COPD prevention KAP assessment was used for evaluation which included knowledge(21 items),attitude(9 items),and practice(9 items)three dimension,39 items.Results The average overall KAP score was 68.29±12.91,with scores for the knowledge,attitude,and practice dimension was 68.75±18.07,71.13±15.09 and 65.00±20.93,respectively.Among the people at risk of COPD,76.8%experienced a moderate level of KAP toward COPD prevention,while 22.0%were at a poor level.Significant differences in the KAP scores were based on gender,educational level,occupation,type of medical insurance,smoking,and passive smoking status(P<0.05).The male COPD high-risk group has better KAP toward COPD prevention than the female group(P<0.05).The knowledge and attitude of COPD prevention present worse in people with a high risk of COPD aged 70 or above,primary school and below educational level,and farmers(P<0.05).Smoking and passive smoking groups have higher recognition of the knowledge but the lower practice of COPD prevention(P<0.05).Conclusion The participants with a high risk of COPD had a moderate level of KAP for COPD prevention,in which the understanding and action on vaccination and lung function test was weak,but an active attitude for health.It is necessary to implement tailored health education interventions to their characteristics to reduce the incidence and development of COPD.展开更多
In large Solar Energetic Particle (SEP) events, ions can be accelerated at coronal mass ejection (CME)-driven shocks to very high energies. The spectra of heavy ions in many large SEP events show features such as ...In large Solar Energetic Particle (SEP) events, ions can be accelerated at coronal mass ejection (CME)-driven shocks to very high energies. The spectra of heavy ions in many large SEP events show features such as roll-overs or spectral breaks. In some events when the spectra are plotted in terms of energy/nucleon, they can be shifted relative to each other to make the spectral breaks align. The amount of shift is charge to mass ratio (Q/A) dependent and varies from event to event. This can be understood if the spectra of heavy ions are organized by the diffusion coefficients (Cohen et al. 2005). In the work of Li et al. (2009), the Q/A dependence of the scaling is related to shock geometry when the CME-driven shock is close to the Sun. For events where multiple in-situ spacecraft observations exist, one may expect that different spacecraft are connected to different portions of the CME-driven shock that have different shock geometries, therefore yielding different Q/A dependence. In this work, we examine one SEP event which occurred on 2013 November 4. We study the Q/A dependence of the energy scaling for heavy ion spectra using helium, oxygen and iron ions. Observations from STEREO-A, STEREO-B and ACE are examined. We find that the scalings are different for different spacecraft. We suggest that this is because ACE, STEREO- A and STEREO-B are connected to different parts of the shock that have different shock geometries. Our analysis indicates that studying the Q/A scaling of in-situ particle spectra can serve as a powerful tool to remotely examine the shock geometry for large SEP events.展开更多
Production of reactive oxygen species(ROS)via the activity of respiratory burst oxidase homologs(RBOHs)plays a vital role in multiple layers of the plant immune system,including pathogen-associated molecular pattern-t...Production of reactive oxygen species(ROS)via the activity of respiratory burst oxidase homologs(RBOHs)plays a vital role in multiple layers of the plant immune system,including pathogen-associated molecular pattern-triggered immunity(PTI),damage-associated molecular pattern-triggered immunity(DTI),effector-triggered immunity(ETI),and systemic acquired resistance(SAR).It is generally established that RBOHD is activated by different receptor-like cytoplasmic kinases(RLCKs)in response to various immune elicitors.In this study,we showed that RPM1-INDUCED PROTEIN KINASE(RIPK),an RLCK VII subfamily member,contributes to ROS production in multiple layers of plant immune system.The ripk mutants showed reduced ROS production in response to treatment with all examined immune elicitors that trigger PTI,DTI,ETI,and SAR.We found that RIPK can directly phosphorylate the N-terminal region of RBOHD in vitro,and the levels of phosphorylated S343/S347 residues of RBOHD are sigfniciantly lower in ripk mutants compared with the wild type upon treatment with all tested immune elicitors.We further demonstrated that phosphorylation of RIPK is required for its function in regulating RBOHD-mediated ROS production.Similar to rbohd,ripk mutants showed reduced stomatal closure and impaired SAR,and were susceptible to the necrotrophic bacterium Pectobacterium carotovorum.Collectively,our results indicate that RIPK regulates broad-spectrum RBOHD-mediated ROS signaling during PTI,DTI,ETI,and SAR,leading to subsequent RBOHD-dependent immune responses.展开更多
Determining atomistic structures of grain boundaries (GBs) is essential to understand structure--property interplay in oxides.Here,different GB superstructures in CuO nanosheets,including (111) and (114) twinning boun...Determining atomistic structures of grain boundaries (GBs) is essential to understand structure--property interplay in oxides.Here,different GB superstructures in CuO nanosheets,including (111) and (114) twinning boundaries (TBs) and (002)/(223) GB,are investigated.Unlike the lower-energy stoichiometric (111) TB,both experimental and first-principles investigations reveal a severe segregation of Cu and O vacancies and a nonstoichiometric property at (114) TB,which may facilitate ionic transportation and provide space for elemental segregation.More importantly,the calculated electronic structures have shown the increased conductivity as well as the unanticipated magnetism in both (114) TB and (002)/(223) GB.These findings could contribute to the race towards the property-directing structural design by GB engineering.展开更多
Plant immunity must be tightly controlled to avoid activation of defense mechanisms in the absence of pathogen attack. Protein phosphorylation is a common mechanism regulating immune signaling. In Arabidopsis thaliana...Plant immunity must be tightly controlled to avoid activation of defense mechanisms in the absence of pathogen attack. Protein phosphorylation is a common mechanism regulating immune signaling. In Arabidopsis thaliana, nine members of the type one protein phosphatase(TOPP) family(also known as protein phosphatase 1, PP1) have been identified. Here, we characterized the autoimmune phenotype of topp4-1, a previously identified dominant-negative mutant of TOPP4. Epistasis analysis showed that defense activation in topp4-1 depended on NON-RACE-SPECIFIC DISEASE RESISTANCE1,PHYTOALEXIN DEFICIENT4, and the salicylic acid pathway.We generated topp1/4/5/6/7/8/9 septuple mutants to investigate the function of TOPPs in plant immunity. Elevated defense gene expression and enhanced resistance to Pseudomonas syringae pv. tomato(Pst) DC3000 in the septuple mutant indicate that TOPPs function in plant defense responses. Furthermore, TOPPs physically interacted with mitogen-activated protein kinases(MAPKs)and affected the MAPK-mediated downstream defense pathway. Thus, our study reveals that TOPPs are important regulators of plant immunity.展开更多
To understand climate changes recorded in the Luochuan loess-palaeosols, Shaanxi province, northwes- tern China, clay mineralogy was studied using X-ray diffraction (XRD), high-resolution transmission electron micro...To understand climate changes recorded in the Luochuan loess-palaeosols, Shaanxi province, northwes- tern China, clay mineralogy was studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) methods. XRD results show that clay mineral compositions in the Luochuan loess-palaeosols are dom- inantly illite, with minor chlorite, kaolinite, smectite, and illite-smectite mixed-layer clays (US). Illite is the most abundant species in the sediments, with a content of 61%- 83%. The content of chlorite ranges from 5%-22%, and the content of kaolinite ranges from 5%-19%. Smectite (or US) occurs discontinuously along the loess profile, with a content of 0-8%. The Kfibler index of illite (IC) ranges from 0.255°-0.491°, and the illite chemical index (ICI) ranges from 0.294-0.394. The CIA values of the loess- palaeosols are 61.9-69.02, and the R3+/(R3+ + R2+ + M+) values are 0.508-0.589. HRTEM observations show that transformation of illite to illite-smectite has occurred in both the loess and palaeosol, suggesting that the Luochuan loess-palaeosols have experienced a certain degree of chemical weathering. The Luochuan loess-palaeosols have the same clay mineral assemblage along the profile. However, the relative contents of clay mineral species, CIA, ICI, and IC values fluctuate frequently along the profile, and all these parameters display a similar trend. Moreover, climate changes suggested by the clay index are consistent with variations in the deep-sea 6180 records and the magnetic susceptibility value, and thus, climate changes in the Luochuan region have been controlled by global climate change.展开更多
基金supported by the National Natural Science Foundation of China(52374301 and 22279030)the Fundamental Research Funds for the Central Universities(N2223037)+1 种基金Hebei Key Laboratory of Dielectric and Electrolyte Functional Material,Northeastern University at Qinhuangdao(HKDEFM2021201)the Performance subsidy fund for the Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(22567627H)。
文摘The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis strategy.The experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon material.The FeCo/SNC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E_(1/2)=0.8823 V)for ORR and a low overpotential at 10 mA cm^(-2)(E_(j=10)=299 mV)for OER.In addition,compared with Pt/C+RuO_(2) assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 mA h g_(zn)~(-1)),and ultra-stable cycle performance.These results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.
基金supported by grant from the National Key R&D Program of China(grant number:2017YFC0908300)the Fun-damental Research Funds for the Central Universities(grant number:3332023136).
文摘Objective:Accurate prognosis prediction is critical for individualized-therapy making of gastric cancer patients.We aimed to develop and test 6-month,1-,2-,3-,5-,and 10-year overall survival(OS)and cancer-specific survival(CSS)prediction models for gastric cancer patients following gastrectomy.Methods:We derived and tested Survival Quilts,a machine learning-based model,to develop 6-month,1-,2-,3-,5-,and 10-year OS and CSS prediction models.Gastrectomy patients in the development set(n=20,583)and the internal validation set(n=5,106)were recruited from the Surveillance,Epidemiology,and End Re-sults(SEER)database,while those in the external validation set(n=6,352)were recruited from the China National Cancer Center Gastric Cancer(NCCGC)database.Furthermore,we selected gastrectomy patients with-out neoadjuvant therapy as a subgroup to train and test the prognostic models in order to keep the accuracy of tumor-node-metastasis(TNM)stage.Prognostic performances of these OS and CSS models were assessed using the Concordance Index(C-index)and area under the curve(AUC)values.Results:The machine learning model had a consistently high accuracy in predicting 6-month,1-,2-,3-,5-,and 10-year OS in the SEER development set(C-index=0.861,0.832,0.789,0.766,0.740,and 0.709;AUC=0.784,0.828,0.840,0.849,0.869,and 0.902,respectively),SEER validation set(C-index=0.782,0.739,0.712,0.698,0.681,and 0.660;AUC=0.751,0.772,0.767,0.762,0.766,and 0.787,respectively),and NCCGC set(C-index=0.691,0.756,0.751,0.737,0.722,and 0.701;AUC=0.769,0.788,0.790,0.790,0.787,and 0.788,respectively).The model was able to predict 6-month,1-,2-,3-,5-,and 10-year CSS in the SEER development set(C-index=0.879,0.858,0.820,0.802,0.784,and 0.774;AUC=0.756,0.827,0.852,0.863,0.874,and 0.884,respectively)and SEER validation set(C-index=0.790,0.763,0.741,0.729,0.718,and 0.708;AUC=0.706,0.758,0.767,0.766,0.766,and 0.764,respectively).In multivariate analysis,the high-risk group with risk score output by 5-year OS model was proved to be a strong survival predictor both in the SEER development set(hazard ratio[HR]=14.59,95%confidence interval[CI]:1.872-2.774,P<0.001),SEER validation set(HR=2.28,95%CI:13.089-16.293,P<0.001),and NCCGC set(HR=1.98,95%CI:1.617-2.437,P<0.001).We further explored the prognostic value of risk score resulted 5-year CSS model of gastrectomy patients,and found that high-risk group remained as an independent CSS factor in the SEER development set(HR=12.81,95%CI:11.568-14.194,P<0.001)and SEER validation set(HR=1.61,95%CI:1.338-1.935,P<0.001).Conclusion:Survival Quilts could allow accurate prediction of 6-month,1-,2-,3-,5-,and 10-year OS and CSS in gastric cancer patients following gastrectomy.
基金supported by China Agriculture Research System of MOF and MARA(CARS-42)the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CXGC-IAS-09)Central Scientific Institution Fundamental Research Funds(1610382022005).
文摘Background:Although methionine(Met),the first-limiting dietary amino acid,has crucial roles in growth and regulation of lipid metabolism in ducks,mechanisms underlying are not well understood.Therefore,the objective was to use dietary Met deficiency to investigate the involvement of Met in lipid metabolism and fat accumulation of Pekin ducks.Methods:A total of 150 male Pekin ducks(15-d-old,558.5±4.4 g)were allocated into 5 groups(6 replicates with 5 birds each)and fed corn and soybean meal-based diets containing 0.28%,0.35%,0.43%,0.50%,and 0.58%Met,respectively,for 4 weeks.Met-deficient(Met-D,0.28%Met)and Met-adequate(Met-A,0.43%Met)groups were selected for subsequent molecular studies.Serum,liver,and abdominal fat samples were collected to assess the genes and proteins involved in lipid metabolism of Pekin ducks and hepatocytes were cultured in vivo for verification.Results:Dietary Met deficiency caused growth depression and excess fat deposition that were ameliorated by feeding diets with adequate Met.Serum triglyceride and non-esterified fatty acid concentrations increased(P<0.05),whereas serum concentrations of total cholesterol,low density lipoprotein cholesterol,total protein,and albumin decreased(P<0.05)in Met-D ducks compared to those in Met-A ducks.Based on hepatic proteomics analyses,dietary Met deficiency suppressed expression of key proteins related to fatty acid transport,fatty acid oxidation,tricarboxylic acid cycle,glycolysis/gluconeogenesis,ketogenesis,and electron transport chain;selected key proteins had similar expression patterns verified by qRT-PCR and Western blotting,which indicated these processes were likely impaired.In vitro verification with hepatocyte models confirmed albumin expression was diminished by Met deficiency.Additionally,in abdominal fat,dietary Met deficiency increased adipocyte diameter and area(P<0.05),and down-regulated(P<0.05)of lipolytic genes and proteins,suggesting Met deficiency may suppress lipolysis in adipocyte.Conclusion:Taken together,these data demonstrated that dietary Met deficiency in Pekin ducks resulted in stunted growth and excess fat deposition,which may be related to suppression of fatty acids transportation and hepatic catabolism.
文摘Objective This study aimed to describe the current situation of knowledge,attitude,and practice(KAP)of chronic obstructive pulmonary disease(COPD)prevention among a high-risk population for COPD.Methods A cross-sectional survey was conducted.A total of 241 participants at risk of COPD were selected who visited the respiratory outpatient department of a Class A tertiary hospital in Chongqing,China from January to December 2021.A self-developed COPD prevention KAP assessment was used for evaluation which included knowledge(21 items),attitude(9 items),and practice(9 items)three dimension,39 items.Results The average overall KAP score was 68.29±12.91,with scores for the knowledge,attitude,and practice dimension was 68.75±18.07,71.13±15.09 and 65.00±20.93,respectively.Among the people at risk of COPD,76.8%experienced a moderate level of KAP toward COPD prevention,while 22.0%were at a poor level.Significant differences in the KAP scores were based on gender,educational level,occupation,type of medical insurance,smoking,and passive smoking status(P<0.05).The male COPD high-risk group has better KAP toward COPD prevention than the female group(P<0.05).The knowledge and attitude of COPD prevention present worse in people with a high risk of COPD aged 70 or above,primary school and below educational level,and farmers(P<0.05).Smoking and passive smoking groups have higher recognition of the knowledge but the lower practice of COPD prevention(P<0.05).Conclusion The participants with a high risk of COPD had a moderate level of KAP for COPD prevention,in which the understanding and action on vaccination and lung function test was weak,but an active attitude for health.It is necessary to implement tailored health education interventions to their characteristics to reduce the incidence and development of COPD.
基金supported at UAH by NSF grants AGS-1135432 and AGS-1622391NASA grant NNX15AJ93G+5 种基金at APL by NASA grant NNX13AR20G/115828 (ACE/ULEIS and STEREO/SIT)NASA subcontract SA4889-26309 from the University of California Berkeleyat Caltech by NNX13A66G, NNX11A075Gsubcontract 00008864 of NNX15AG09Gby NSF grant AGS-1156004at SwRI partially by NSF grant AGS-1460118
文摘In large Solar Energetic Particle (SEP) events, ions can be accelerated at coronal mass ejection (CME)-driven shocks to very high energies. The spectra of heavy ions in many large SEP events show features such as roll-overs or spectral breaks. In some events when the spectra are plotted in terms of energy/nucleon, they can be shifted relative to each other to make the spectral breaks align. The amount of shift is charge to mass ratio (Q/A) dependent and varies from event to event. This can be understood if the spectra of heavy ions are organized by the diffusion coefficients (Cohen et al. 2005). In the work of Li et al. (2009), the Q/A dependence of the scaling is related to shock geometry when the CME-driven shock is close to the Sun. For events where multiple in-situ spacecraft observations exist, one may expect that different spacecraft are connected to different portions of the CME-driven shock that have different shock geometries, therefore yielding different Q/A dependence. In this work, we examine one SEP event which occurred on 2013 November 4. We study the Q/A dependence of the energy scaling for heavy ion spectra using helium, oxygen and iron ions. Observations from STEREO-A, STEREO-B and ACE are examined. We find that the scalings are different for different spacecraft. We suggest that this is because ACE, STEREO- A and STEREO-B are connected to different parts of the shock that have different shock geometries. Our analysis indicates that studying the Q/A scaling of in-situ particle spectra can serve as a powerful tool to remotely examine the shock geometry for large SEP events.
基金Financial support for this study was provided by the National Key Research and Development Program of China(2018YFD1000800)National Natural Science Foundation of China(31970279 and 31801015)China Postdoctoral Science Foundation(2019T120522 and 2019M652101).
文摘Production of reactive oxygen species(ROS)via the activity of respiratory burst oxidase homologs(RBOHs)plays a vital role in multiple layers of the plant immune system,including pathogen-associated molecular pattern-triggered immunity(PTI),damage-associated molecular pattern-triggered immunity(DTI),effector-triggered immunity(ETI),and systemic acquired resistance(SAR).It is generally established that RBOHD is activated by different receptor-like cytoplasmic kinases(RLCKs)in response to various immune elicitors.In this study,we showed that RPM1-INDUCED PROTEIN KINASE(RIPK),an RLCK VII subfamily member,contributes to ROS production in multiple layers of plant immune system.The ripk mutants showed reduced ROS production in response to treatment with all examined immune elicitors that trigger PTI,DTI,ETI,and SAR.We found that RIPK can directly phosphorylate the N-terminal region of RBOHD in vitro,and the levels of phosphorylated S343/S347 residues of RBOHD are sigfniciantly lower in ripk mutants compared with the wild type upon treatment with all tested immune elicitors.We further demonstrated that phosphorylation of RIPK is required for its function in regulating RBOHD-mediated ROS production.Similar to rbohd,ripk mutants showed reduced stomatal closure and impaired SAR,and were susceptible to the necrotrophic bacterium Pectobacterium carotovorum.Collectively,our results indicate that RIPK regulates broad-spectrum RBOHD-mediated ROS signaling during PTI,DTI,ETI,and SAR,leading to subsequent RBOHD-dependent immune responses.
基金the National Natural Science Foundation of China (Nos.51671148,51271134,J1210061,11674251,51501132, and 51601132)the Hubei Provincial Natural Science Foundation of China (Nos.2016CFB446 and 2016CFB155)+4 种基金the Fundamental Research Funds for the Central Universitiesthe CERS-1-26 (CERSChina Equipment and Education Resources System)the China Postdoctoral Science Foundation (No.2014T70734)the Open Research Fund of Science and Technology on High Strength Structural Materials Laboratory (Central South University)the Suzhou Science and Technology project (No.SYG201619).
文摘Determining atomistic structures of grain boundaries (GBs) is essential to understand structure--property interplay in oxides.Here,different GB superstructures in CuO nanosheets,including (111) and (114) twinning boundaries (TBs) and (002)/(223) GB,are investigated.Unlike the lower-energy stoichiometric (111) TB,both experimental and first-principles investigations reveal a severe segregation of Cu and O vacancies and a nonstoichiometric property at (114) TB,which may facilitate ionic transportation and provide space for elemental segregation.More importantly,the calculated electronic structures have shown the increased conductivity as well as the unanticipated magnetism in both (114) TB and (002)/(223) GB.These findings could contribute to the race towards the property-directing structural design by GB engineering.
基金supported by the Ministry of Agriculture of the People’s Republic of China(2016ZX08009-003-002)the Major Project of Science and Technology of Gansu Province(17ZD2NA016)+2 种基金the National Natural Science Foundation of China(NSFC)(31870251,31600156)the Chang Jiang Scholars Program of China(2017)Fundamental Research Funds for the Central Universities(lzujbky-2015-226)。
文摘Plant immunity must be tightly controlled to avoid activation of defense mechanisms in the absence of pathogen attack. Protein phosphorylation is a common mechanism regulating immune signaling. In Arabidopsis thaliana, nine members of the type one protein phosphatase(TOPP) family(also known as protein phosphatase 1, PP1) have been identified. Here, we characterized the autoimmune phenotype of topp4-1, a previously identified dominant-negative mutant of TOPP4. Epistasis analysis showed that defense activation in topp4-1 depended on NON-RACE-SPECIFIC DISEASE RESISTANCE1,PHYTOALEXIN DEFICIENT4, and the salicylic acid pathway.We generated topp1/4/5/6/7/8/9 septuple mutants to investigate the function of TOPPs in plant immunity. Elevated defense gene expression and enhanced resistance to Pseudomonas syringae pv. tomato(Pst) DC3000 in the septuple mutant indicate that TOPPs function in plant defense responses. Furthermore, TOPPs physically interacted with mitogen-activated protein kinases(MAPKs)and affected the MAPK-mediated downstream defense pathway. Thus, our study reveals that TOPPs are important regulators of plant immunity.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 41272053 and 41472041). C.W. acknowledges a postdoctoral science foundation of China (2015M582301), Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan), and National Natural Science Youth Foundation of China (Grant No. 41602037). The authors wish to thank Dr. Yu J. S. for XRD analysis, Dr. Liu X. W, for HRTEM analysis and Dr. Yang H. and Dr. Yang Q. for SEM analysis.
文摘To understand climate changes recorded in the Luochuan loess-palaeosols, Shaanxi province, northwes- tern China, clay mineralogy was studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) methods. XRD results show that clay mineral compositions in the Luochuan loess-palaeosols are dom- inantly illite, with minor chlorite, kaolinite, smectite, and illite-smectite mixed-layer clays (US). Illite is the most abundant species in the sediments, with a content of 61%- 83%. The content of chlorite ranges from 5%-22%, and the content of kaolinite ranges from 5%-19%. Smectite (or US) occurs discontinuously along the loess profile, with a content of 0-8%. The Kfibler index of illite (IC) ranges from 0.255°-0.491°, and the illite chemical index (ICI) ranges from 0.294-0.394. The CIA values of the loess- palaeosols are 61.9-69.02, and the R3+/(R3+ + R2+ + M+) values are 0.508-0.589. HRTEM observations show that transformation of illite to illite-smectite has occurred in both the loess and palaeosol, suggesting that the Luochuan loess-palaeosols have experienced a certain degree of chemical weathering. The Luochuan loess-palaeosols have the same clay mineral assemblage along the profile. However, the relative contents of clay mineral species, CIA, ICI, and IC values fluctuate frequently along the profile, and all these parameters display a similar trend. Moreover, climate changes suggested by the clay index are consistent with variations in the deep-sea 6180 records and the magnetic susceptibility value, and thus, climate changes in the Luochuan region have been controlled by global climate change.