Introducing vacancies and constructing S-scheme heterojunctions are promising approaches for enhancing photocatalytic activity.However,the application of this synergistic strategy to realize inexpensive and efficient ...Introducing vacancies and constructing S-scheme heterojunctions are promising approaches for enhancing photocatalytic activity.However,the application of this synergistic strategy to realize inexpensive and efficient photocatalysts remains challenging.In this study,a straightforward hydrothermal and calcination modification strategy was used to prepare a photocatalyst in which abundant nitrogen-oxygen vacancies were coupled with a Ce-ZnO@C-g-C_(3)N_(4)composite with an S-scheme heterojunction.Under sunlight irradiation,the prepared composite achieves 98.3%and 86.4%degradation of methylene blue and ciprofloxacin,with degradation rate constants of 0.3464 and 0.0893 min^(-1),respectively.Compared with ZnO and g-C_(3)N_(4),the degradation rates of methylene blue over the composite catalyst are 34.8 and 22.7 times higher,respectively,and those of ciprofloxacin are 2.4 and 4.9 times higher,respectively.Based on a detailed examination of the catalyst structure and photoelectric properties,the high photocatalytic efficiency is attributed to nitrogen-oxygen vacancies,an enhanced surface area,and synergistic S-scheme heterojunction effects.These factors broaden the spectral range,increase the number of active sites,and facilitate efficient charge transfer,thereby enhancing the photocatalytic reaction.This system demonstrates the feasibility of integrating doping and heterojunction formation to enhance photocatalytic performance synergistically.展开更多
Metal(iso)cyanides dominate the molecular inventory of metal-bearing species in the interstellar medium.Their oxide counterparts,metal(iso)cyanates,have potential as interstellar molecules and have received significan...Metal(iso)cyanides dominate the molecular inventory of metal-bearing species in the interstellar medium.Their oxide counterparts,metal(iso)cyanates,have potential as interstellar molecules and have received significant attention.However,cationic complexes HNCOM^(+)as precursors to metal(iso)cyanates are rarely studied.Herein,we investigated HNCOCa^(+)by exploiting infrared spectrometry with isotopic substitutions and quantum chemical calculations.For comparison,the light and heavy alkaline earth metal cationic complexes HNCOBe^(+)and HNCOBa^(+)were also explored.HNCOCa^(+)and HNCOBe^(+)rather than HNCOBa^(+)can be experimentally generated by the reactions of metal cations with HNCO.The observed antisymmetric and symmetric NCO stretching vibrations in HNCOCa^(+)(2362.6 and 1330.4 cm^(−1))are higher than those in free HNCO(2268.5 and 1320.3 cm^(−1))but lower than those in HNCOBe^(+)(2426.4 and 1355.2 cm^(−1)).These shifts can be explained by the charge polarization within the NCO fragment in HNCOBe^(+)and HNCOCa^(+).Bonding analysis suggests that HNCO−Be^(+)bond favors covalent character(54%)while HNCO−Ca^(+)bond has higher electrostatic character(57%).The dominant electrostatic interaction(64%)in HNCO−Ba^(+)bond results in the low bond energy,which might account for its absence in experiments.展开更多
In May and October 2017,12 stations were set up in the Central Bohai Sea for fishery resources investigation.The results show that there are many dominant species in this area,and the inshore fishery resources are hig...In May and October 2017,12 stations were set up in the Central Bohai Sea for fishery resources investigation.The results show that there are many dominant species in this area,and the inshore fishery resources are higher than those in the open sea because of the abundant nutrients from land,the high density of zooplankton and the food of swimming animals.In order to effectively protect the fishery resources in the Central Bohai Sea,this paper puts forward some suggestions,such as strengthening the protection propaganda,scientific and reasonable fishing,and strengthening the management of marine environment.展开更多
Space charge accumulation in polypropylene materials for direct current capacitor will accelerate the ageing of the materials,resulting in the degradation of their insulation properties.Besides,it will also affect the...Space charge accumulation in polypropylene materials for direct current capacitor will accelerate the ageing of the materials,resulting in the degradation of their insulation properties.Besides,it will also affect the dielectric properties of the capacitor in a long term.In this paper,a ternary composite of polyaniline(PANI)/maleic anhydride functionalised PP(PP-g-MAH)/polypropylene(PP)based on the PANI@dopamine(PDA)coating structure is constructed from two perspectives of PP matrix grafting and PANI nano particle.This method takes advantage of the high permittivity and good compatibility of PANI to improve the relative dielectric constant of the composite while introducing deep traps inside the composite to inhibit space charge accumulation coating.The experimental results show that with the increase in PANI content,the maximum relative permittivity can be increased by 62%.The addition of the appropriate amount of PANI can effectively inhibit the space charge accumulation.The relative dielectric constant of the composite decreases significantly due to the heteropolar space charge.The relative dielectric constant of the modified polyaniline composites decreased significantly.The reduction rate decreased from 38%before modification to 12%after modification.This work has certain guiding significance for solving space charge problem of direct current capacitor.展开更多
The performance of polypropylene film determines the reliability of capacitors.This paper studies the change of insulation characteristics of the insulation dielectric polypropylene of high-voltage capacitors during t...The performance of polypropylene film determines the reliability of capacitors.This paper studies the change of insulation characteristics of the insulation dielectric polypropylene of high-voltage capacitors during the long-term operation process.Moreover,the correction of the insulation failure model of polypropylene media is implemented.Some conclusions are drawn from a series of experiments.The breakdown strength of the insulation dielectrics decreases as the withstand time rises,with amaximum decrease of 37.91%compared to the polypropylene sample without withstand voltage.As the electric field increases from−20 to−100 kV/mm,the total amount of space charge,the trap energy level and the trap density inside the polypropylene increase by 524.15%,18.99%and 773.36%,respectively.In the capacitor simulation model,the electric field in the capacitor increases by 19.62%after presetting space charge relative to the nonspace charge.The experimental data are substituted into the inverse power model,and the trap parameters are used to modify the model.The results show that the ageing state of the polypropylene has a negative exponential relationship with the trap parameters.This paper provides an important reference for the study of the failure mechanism of polypropylene in high-voltage capacitors and the assessment of polypropylene ageing state.展开更多
Hierarchical porous MgO is a promising adsorbent for dye removal because of its large Brunauer-Emmett-Teller specific surface area(SBET)and abundant low-coordinated oxygen anions(LCO)sites.As hierarchical porous MgO p...Hierarchical porous MgO is a promising adsorbent for dye removal because of its large Brunauer-Emmett-Teller specific surface area(SBET)and abundant low-coordinated oxygen anions(LCO)sites.As hierarchical porous MgO particles with large SBET values are typically prepared by complicated procedures under harsh conditions,such as high temperatures and high pressures,their large-scale production is impractical.Consequently,the preparation of hierarchical porous MgO with a large SBET value under mild conditions is highly desirable.In this study,a morphology transition engineering strategy is introduced to change the morphology of simple MgO microspheres to an embroidered ball-shaped with a larger SBET value via hydrolysis and calcination without using surfactants as sacrificial templates.During hydrolysis,numerous Mg(OH)_(2)sheets form and attach to the MgO surface,thus increasing the SBET value of the newly obtained MgO that forms by calcination(denoted as NM-x,where x is the hydrolysis time in hours).The sizes of the crystalline sheets were tuned by controlling the hydrolysis time.NM-12 exhibited the highest density of small-sized sheets on its surface and the largest SBET value of 180.17 m^(2)g^(-1),which was 3.51 times that of the MgO precursor(51.89 m^(2)g^(-1)).However,NM-24(134.07 m^(2)g^(-1))had a higher adsorption efficiency for Congo red(CR)than NM-12,despite having a smaller SBET value,which indicates that other factors are involved.NM-24 exhibited a lower probability of exposed(200)and(220)facets which were verified to repulse CR molecules by molecular dynamics simulations,and a greater number of LCO sites,which contributed to adsorption.Thus,this study introduces a facile method for preparing hierarchical porous MgO and examines the effects of LCO sites and exposed facet probabilities on its adsorption properties.展开更多
Superabsorbent Polymer(SAP)has emerged as a topic of considerable interest in recent years.The present study systematically and quantitively investigated the effect of SAP on hydration,autogenous shrinkage,mechanical ...Superabsorbent Polymer(SAP)has emerged as a topic of considerable interest in recent years.The present study systematically and quantitively investigated the effect of SAP on hydration,autogenous shrinkage,mechanical properties,and microstructure of cement mortars.Influences of SAP on hydration heat and autogenous shrinkage were studied by utilizing TAM AIR technology and a non-contact autogenous shrinkage test method.Scanning Electron Microscope(SEM)was employed to assess the microstructure evolution.Although SAP decreased the peak rate of hydration heat and retarded the hydration,it significantly increased the cumulative heat,indicating SAP helps promote the hydration.Hydration promotion caused by SAP mainly occurred in the deceleration period and attenuation period.SAP can significantly mitigate the autogenous shrinkage when the content ranged from 0 to 0.5%.Microstructure characteristics showed that pores and gaps were introduced when SAP was added.The microstructure difference caused by SAP contributed to the inferior mechanical behaviors of cement mortars treated by SAP.展开更多
An unexpected observation among the COVID-19 pandemic is that smokers constituted only 1.4%–18.5%of hospitalized adults,calling for an urgent investigation to determine the role of smoking in SARS-CoV-2 infection.Her...An unexpected observation among the COVID-19 pandemic is that smokers constituted only 1.4%–18.5%of hospitalized adults,calling for an urgent investigation to determine the role of smoking in SARS-CoV-2 infection.Here,we show that cigarette smoke extract(CSE)and carcinogen benzo(a)pyrene(BaP)increase ACE2 mRNA but trigger ACE2 protein catabolism.BaP induces an aryl hydrocarbon receptor(AhR)-dependent upregulation of the ubiquitin E3 ligase Skp2 for ACE2 ubiquitination.ACE2 in lung tissues of non-smokers is higher than in smokers,consistent with the findings that tobacco carcinogens downregulate ACE2 in mice.Tobacco carcinogens inhibit SARS-CoV-2 spike protein pseudovirions infection of the cells.Given that tobacco smoke accounts for 8 million deaths including 2.1 million cancer deaths annually and Skp2 is an oncoprotein,tobacco use should not be recommended and cessation plan should be prepared for smokers in COVID-19 pandemic.展开更多
Many differentiated plant organs have the ability to regenerate into a new plant after detachment via de novo organogenesis. During de novo root organogenesis from Arabidopsis thaliana leaf explants, wounding first in...Many differentiated plant organs have the ability to regenerate into a new plant after detachment via de novo organogenesis. During de novo root organogenesis from Arabidopsis thaliana leaf explants, wounding first induces endogenous auxin production in mesophyll cells. Auxin is then polar transported to, and accumulates in, regenerationcompetent cells near the wound to trigger the cell-fate transition. The TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS(TAA) family proteins and the YUCCA(YUC) family proteins catalyze two successive biochemical steps in auxin biogenesis, and YUCs have been shown to be involved in auxin production in mesophyll cells during de novo root organogenesis. In thisstudy, we show that the TAA family is also required for adventitious rooting. Inhibition of TAA blocked adventitious root formation from leaf explants. Intriguingly,whereas YUC1 and YUC4 have been shown to be highly induced by wounding, TAA genes retained consistent expression levels before and after leaf detachment.Therefore, we suggest that TAAs and YUCs are both required for auxin biogenesis in leaf explants, but they play different roles in regeneration. While YUC1 and YUC4 function in response to wounding to catalyze the ratelimiting step in auxin biosynthesis, TAAs probably serve as abiding and basal enzymes during de novo root organogenesis from leaf explants.展开更多
The characteristic genetic abnormality of neuroendocrine neoplasms(NENs),a heterogeneous group of tumors found in various organs,remains to be identified.Here,based on the analysis of the splicing variants of an oncog...The characteristic genetic abnormality of neuroendocrine neoplasms(NENs),a heterogeneous group of tumors found in various organs,remains to be identified.Here,based on the analysis of the splicing variants of an oncogene Focal Adhesion Kinase(FAK)in The Cancer Genome Atlas datasets that contain 9193 patients of 33 cancer subtypes,we found that Box 6/Box 7-containing FAK variants(FAK^(6/7))were observed in 7(87.5%)of 8 pancreatic neuroendocrine carcinomas and 20(11.76%)of 170 pancreatic ductal adenocarcinomas(PDACs).We tested FAK variants in 157 tumor samples collected from Chinese patients with pancreatic tumors,and found that FAK^(6/7)was positive in 34(75.6%)of 45 pancreatic NENs,19(47.5%)of 40 pancreatic solid pseudopapillary neoplasms,and 2(2.9%)of 69 PDACs.We further tested FAK splicing variants in breast neuroendocrine carcinoma(BrNECs),and found that FAK^(6/7)was positive in 14(93.3%)of 15 BrNECs but 0 in 23 non-NEC breast cancers.We explored the underlying mechanisms and found that a splicing factor serine/arginine repetitive matrix protein 4(SRRM4)was overexpressed in FAK^(6/7)-positive pancreatic tumors and breast tumors,which promoted the formation of FAK^(6/7)in cells.These results suggested that FAK^(6/7)could be a biomarker of NENs and represent a potential therapeutic target for these orphan diseases.展开更多
In cuttings,adventitious roots can be regenerated from detached or wounded plant organs,and this process is known as de novo root regeneration.In Arabidopsis thaliana leaf cuttings(Liu et al.2014;Xu 2018),detached A.t...In cuttings,adventitious roots can be regenerated from detached or wounded plant organs,and this process is known as de novo root regeneration.In Arabidopsis thaliana leaf cuttings(Liu et al.2014;Xu 2018),detached A.thaliana leaves are responsive to wound signals and many environmental stimuli,and then synthesize a cer-tain level of auxin,which is transported to regeneration-competent cells(i.e.,procambium and some vascular parenchyma cells near the wound site)to promote cell fate transitions for adventitious root organogenesis(Xu 2018).展开更多
Alcohol consumption contributes to global mortality and cancer development.Acetaldehyde(ACE),the oxidized metabolite of alcohol,is highly reactive towards DNA,resulting in DNA adducts.ACE can be detoxified to acetate ...Alcohol consumption contributes to global mortality and cancer development.Acetaldehyde(ACE),the oxidized metabolite of alcohol,is highly reactive towards DNA,resulting in DNA adducts.ACE can be detoxified to acetate by acetaldehyde dehydrogenase type 2(ALDH2).ALDH2 deficiency can lead to ACE accumulation and DNA damage.展开更多
Interdisciplinary research(IDR)plays a vital role in tackling grand and complex challenges such as COVID-19,which has severe consequences for public health,economy,politics,and society.This study compares several face...Interdisciplinary research(IDR)plays a vital role in tackling grand and complex challenges such as COVID-19,which has severe consequences for public health,economy,politics,and society.This study compares several facets of interdisciplinarity that occurred in the research relating to two serious global pandemics in this century,namely SARS and COVID-19,and provides a comprehensive summary of the performance and growth of pandemic-related interdisciplinary research.Generally,the scientific community gathers more multidisciplinary efforts to tackle COVID-19 in comparison to SARS.Firstly,COVID-19 related research from each major field has greater connections with their established expertise and research threads such that they are studying the impact of COVID-19 on their own existing research subjects,while the studies of SARS by different disciplines exhibit less discernable disciplinary characteristics.Secondly,as for the interdisciplinarity observed in the knowledge base of pandemic-related publications,we observe a greater presence of social science knowledge and a more dispersed distribution of knowledge from various disciplines comparing publications on COVID-19 with SARS.Thirdly,regarding interdisciplinarity in research collaboration,COVID-19 publications are on average produced by more interdisciplinary teams than SARS,as measured by the number and diversity of affiliated disciplines of authors.Our discovery on the growth of multidisciplinarity and interdisciplinarity in pandemic-related research signals positive achievement that the scientific community is responding to such a global challenge as a whole and is willing to break down existing disciplinary silos to facilitate the flow of knowledge and breed novelty.展开更多
Surface discharge is a typical fault type in electric power equipment.High temperature in long-term operation can easily lead to ageing of materials,resulting in changes in surface characteristics and surface discharg...Surface discharge is a typical fault type in electric power equipment.High temperature in long-term operation can easily lead to ageing of materials,resulting in changes in surface characteristics and surface discharge faults.In this paper,a method of surface discharge identification of silicon rubber(SiR)based on spectral detection technology is presented.The surface discharge spectral characteristics of SiR with different ageing degrees are investigated,and the changes of microphysical and chemical properties and surface insulation properties caused by thermal ageing are analysed.The dynamic evolution of charge during surface discharge is simulated.The experimental results show that the spectral intensity of the surface discharge of the SiR material is mainly concentrated at 350,600 and 750-900 nm bands.The spectral intensity reaches the maximum value when the ageing time is 168 h.With the intensification of ageing,no new characteristic peaks generate in the discharge spectrum,but the proportion of the same characteristic peaks to the overall wavelength is different.The type of discharge material and ageing state are determined by the characteristic light intensity ratio Ib.The evolutionary mechanism of the discharge spectrum is revealed by the variation of flashover voltage,trap charge density,resistivity and other parameters.The simulation results show that the increase of electron density will lead to more intense electron collision,which will release more photons,resulting in enhanced spectral intensity.This work can provide a reference for the detection of surface discharge and the evaluation of ageing state of the equipment inside the high voltage box.展开更多
基金Project supported by the Bingtuan Science and Technology Program(2024DA036,2022ZD099)。
文摘Introducing vacancies and constructing S-scheme heterojunctions are promising approaches for enhancing photocatalytic activity.However,the application of this synergistic strategy to realize inexpensive and efficient photocatalysts remains challenging.In this study,a straightforward hydrothermal and calcination modification strategy was used to prepare a photocatalyst in which abundant nitrogen-oxygen vacancies were coupled with a Ce-ZnO@C-g-C_(3)N_(4)composite with an S-scheme heterojunction.Under sunlight irradiation,the prepared composite achieves 98.3%and 86.4%degradation of methylene blue and ciprofloxacin,with degradation rate constants of 0.3464 and 0.0893 min^(-1),respectively.Compared with ZnO and g-C_(3)N_(4),the degradation rates of methylene blue over the composite catalyst are 34.8 and 22.7 times higher,respectively,and those of ciprofloxacin are 2.4 and 4.9 times higher,respectively.Based on a detailed examination of the catalyst structure and photoelectric properties,the high photocatalytic efficiency is attributed to nitrogen-oxygen vacancies,an enhanced surface area,and synergistic S-scheme heterojunction effects.These factors broaden the spectral range,increase the number of active sites,and facilitate efficient charge transfer,thereby enhancing the photocatalytic reaction.This system demonstrates the feasibility of integrating doping and heterojunction formation to enhance photocatalytic performance synergistically.
基金This work was supported by the National Natural Science Foundation of China(No.22025301,No.22273012,and No.22321003).
文摘Metal(iso)cyanides dominate the molecular inventory of metal-bearing species in the interstellar medium.Their oxide counterparts,metal(iso)cyanates,have potential as interstellar molecules and have received significant attention.However,cationic complexes HNCOM^(+)as precursors to metal(iso)cyanates are rarely studied.Herein,we investigated HNCOCa^(+)by exploiting infrared spectrometry with isotopic substitutions and quantum chemical calculations.For comparison,the light and heavy alkaline earth metal cationic complexes HNCOBe^(+)and HNCOBa^(+)were also explored.HNCOCa^(+)and HNCOBe^(+)rather than HNCOBa^(+)can be experimentally generated by the reactions of metal cations with HNCO.The observed antisymmetric and symmetric NCO stretching vibrations in HNCOCa^(+)(2362.6 and 1330.4 cm^(−1))are higher than those in free HNCO(2268.5 and 1320.3 cm^(−1))but lower than those in HNCOBe^(+)(2426.4 and 1355.2 cm^(−1)).These shifts can be explained by the charge polarization within the NCO fragment in HNCOBe^(+)and HNCOCa^(+).Bonding analysis suggests that HNCO−Be^(+)bond favors covalent character(54%)while HNCO−Ca^(+)bond has higher electrostatic character(57%).The dominant electrostatic interaction(64%)in HNCO−Ba^(+)bond results in the low bond energy,which might account for its absence in experiments.
文摘In May and October 2017,12 stations were set up in the Central Bohai Sea for fishery resources investigation.The results show that there are many dominant species in this area,and the inshore fishery resources are higher than those in the open sea because of the abundant nutrients from land,the high density of zooplankton and the food of swimming animals.In order to effectively protect the fishery resources in the Central Bohai Sea,this paper puts forward some suggestions,such as strengthening the protection propaganda,scientific and reasonable fishing,and strengthening the management of marine environment.
基金National Natural Science Foundation of China,Grant/Award Number:52277153。
文摘Space charge accumulation in polypropylene materials for direct current capacitor will accelerate the ageing of the materials,resulting in the degradation of their insulation properties.Besides,it will also affect the dielectric properties of the capacitor in a long term.In this paper,a ternary composite of polyaniline(PANI)/maleic anhydride functionalised PP(PP-g-MAH)/polypropylene(PP)based on the PANI@dopamine(PDA)coating structure is constructed from two perspectives of PP matrix grafting and PANI nano particle.This method takes advantage of the high permittivity and good compatibility of PANI to improve the relative dielectric constant of the composite while introducing deep traps inside the composite to inhibit space charge accumulation coating.The experimental results show that with the increase in PANI content,the maximum relative permittivity can be increased by 62%.The addition of the appropriate amount of PANI can effectively inhibit the space charge accumulation.The relative dielectric constant of the composite decreases significantly due to the heteropolar space charge.The relative dielectric constant of the modified polyaniline composites decreased significantly.The reduction rate decreased from 38%before modification to 12%after modification.This work has certain guiding significance for solving space charge problem of direct current capacitor.
基金supported in part by the National Natural Science Foundation of China(Grant 52277153).
文摘The performance of polypropylene film determines the reliability of capacitors.This paper studies the change of insulation characteristics of the insulation dielectric polypropylene of high-voltage capacitors during the long-term operation process.Moreover,the correction of the insulation failure model of polypropylene media is implemented.Some conclusions are drawn from a series of experiments.The breakdown strength of the insulation dielectrics decreases as the withstand time rises,with amaximum decrease of 37.91%compared to the polypropylene sample without withstand voltage.As the electric field increases from−20 to−100 kV/mm,the total amount of space charge,the trap energy level and the trap density inside the polypropylene increase by 524.15%,18.99%and 773.36%,respectively.In the capacitor simulation model,the electric field in the capacitor increases by 19.62%after presetting space charge relative to the nonspace charge.The experimental data are substituted into the inverse power model,and the trap parameters are used to modify the model.The results show that the ageing state of the polypropylene has a negative exponential relationship with the trap parameters.This paper provides an important reference for the study of the failure mechanism of polypropylene in high-voltage capacitors and the assessment of polypropylene ageing state.
基金supported by the National Natural Science Foundation of China(U22A20434)supported by the foundation from Qinghai Science and Technology Department(2023-ZJ-745).
文摘Hierarchical porous MgO is a promising adsorbent for dye removal because of its large Brunauer-Emmett-Teller specific surface area(SBET)and abundant low-coordinated oxygen anions(LCO)sites.As hierarchical porous MgO particles with large SBET values are typically prepared by complicated procedures under harsh conditions,such as high temperatures and high pressures,their large-scale production is impractical.Consequently,the preparation of hierarchical porous MgO with a large SBET value under mild conditions is highly desirable.In this study,a morphology transition engineering strategy is introduced to change the morphology of simple MgO microspheres to an embroidered ball-shaped with a larger SBET value via hydrolysis and calcination without using surfactants as sacrificial templates.During hydrolysis,numerous Mg(OH)_(2)sheets form and attach to the MgO surface,thus increasing the SBET value of the newly obtained MgO that forms by calcination(denoted as NM-x,where x is the hydrolysis time in hours).The sizes of the crystalline sheets were tuned by controlling the hydrolysis time.NM-12 exhibited the highest density of small-sized sheets on its surface and the largest SBET value of 180.17 m^(2)g^(-1),which was 3.51 times that of the MgO precursor(51.89 m^(2)g^(-1)).However,NM-24(134.07 m^(2)g^(-1))had a higher adsorption efficiency for Congo red(CR)than NM-12,despite having a smaller SBET value,which indicates that other factors are involved.NM-24 exhibited a lower probability of exposed(200)and(220)facets which were verified to repulse CR molecules by molecular dynamics simulations,and a greater number of LCO sites,which contributed to adsorption.Thus,this study introduces a facile method for preparing hierarchical porous MgO and examines the effects of LCO sites and exposed facet probabilities on its adsorption properties.
基金The authors would like to thank the financial sponsorship provided by the National Natural Science Foundation of China(Grant No.51778638).The contents of this paper reflect the views of the authors,who are responsible for the facts and the accuracy of the data presented herein,and do not necessarily reflect any official views or policies.The first author would also like to thank the China Scholarship Council(CSC)for their support.
文摘Superabsorbent Polymer(SAP)has emerged as a topic of considerable interest in recent years.The present study systematically and quantitively investigated the effect of SAP on hydration,autogenous shrinkage,mechanical properties,and microstructure of cement mortars.Influences of SAP on hydration heat and autogenous shrinkage were studied by utilizing TAM AIR technology and a non-contact autogenous shrinkage test method.Scanning Electron Microscope(SEM)was employed to assess the microstructure evolution.Although SAP decreased the peak rate of hydration heat and retarded the hydration,it significantly increased the cumulative heat,indicating SAP helps promote the hydration.Hydration promotion caused by SAP mainly occurred in the deceleration period and attenuation period.SAP can significantly mitigate the autogenous shrinkage when the content ranged from 0 to 0.5%.Microstructure characteristics showed that pores and gaps were introduced when SAP was added.The microstructure difference caused by SAP contributed to the inferior mechanical behaviors of cement mortars treated by SAP.
基金the National Key Research and Development Program of China(Nos.2020YFA0803300 and 2018YFC1313600)the National Natural Science Funds for Distinguished Young Scholar(No.81425025)+2 种基金the Key Project of the National Natural Science Foundation of China(No.81830093)the CAMS Innovation Fund for Medical Sciences(CIFMS,No.2019-I2M-1-003)the National Natural Science Foundation of China(Nos.81672765 and 81802796).
文摘An unexpected observation among the COVID-19 pandemic is that smokers constituted only 1.4%–18.5%of hospitalized adults,calling for an urgent investigation to determine the role of smoking in SARS-CoV-2 infection.Here,we show that cigarette smoke extract(CSE)and carcinogen benzo(a)pyrene(BaP)increase ACE2 mRNA but trigger ACE2 protein catabolism.BaP induces an aryl hydrocarbon receptor(AhR)-dependent upregulation of the ubiquitin E3 ligase Skp2 for ACE2 ubiquitination.ACE2 in lung tissues of non-smokers is higher than in smokers,consistent with the findings that tobacco carcinogens downregulate ACE2 in mice.Tobacco carcinogens inhibit SARS-CoV-2 spike protein pseudovirions infection of the cells.Given that tobacco smoke accounts for 8 million deaths including 2.1 million cancer deaths annually and Skp2 is an oncoprotein,tobacco use should not be recommended and cessation plan should be prepared for smokers in COVID-19 pandemic.
基金supported by the National Basic Research Program of China (973 Program,2014CB943500/2012CB910503)the National Natural Science Foundation of China (91419302/31422005)Youth Innovation Promotion Association CAS
文摘Many differentiated plant organs have the ability to regenerate into a new plant after detachment via de novo organogenesis. During de novo root organogenesis from Arabidopsis thaliana leaf explants, wounding first induces endogenous auxin production in mesophyll cells. Auxin is then polar transported to, and accumulates in, regenerationcompetent cells near the wound to trigger the cell-fate transition. The TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS(TAA) family proteins and the YUCCA(YUC) family proteins catalyze two successive biochemical steps in auxin biogenesis, and YUCs have been shown to be involved in auxin production in mesophyll cells during de novo root organogenesis. In thisstudy, we show that the TAA family is also required for adventitious rooting. Inhibition of TAA blocked adventitious root formation from leaf explants. Intriguingly,whereas YUC1 and YUC4 have been shown to be highly induced by wounding, TAA genes retained consistent expression levels before and after leaf detachment.Therefore, we suggest that TAAs and YUCs are both required for auxin biogenesis in leaf explants, but they play different roles in regeneration. While YUC1 and YUC4 function in response to wounding to catalyze the ratelimiting step in auxin biosynthesis, TAAs probably serve as abiding and basal enzymes during de novo root organogenesis from leaf explants.
基金supported by the Key Project of the National Natural Science Foundation of China (No.81830093)the National Key Research and Development Program of China (Nos.2020YFC2002705,2020YFA0803300,and 2022YFA1103900)+2 种基金the CAMS Innovation Fund for Medical Sciences (CIFMS,Nos.2022-RC310-05 and 2021-RC310-003)the CAMS Initiative for Innovative Medicine (Nos.2021-12M-1-014,2022-I2M-2-001,and 2021-12M-1-021)the National Natural Science Foundation of China (Nos.82073092 and 82273076).
文摘The characteristic genetic abnormality of neuroendocrine neoplasms(NENs),a heterogeneous group of tumors found in various organs,remains to be identified.Here,based on the analysis of the splicing variants of an oncogene Focal Adhesion Kinase(FAK)in The Cancer Genome Atlas datasets that contain 9193 patients of 33 cancer subtypes,we found that Box 6/Box 7-containing FAK variants(FAK^(6/7))were observed in 7(87.5%)of 8 pancreatic neuroendocrine carcinomas and 20(11.76%)of 170 pancreatic ductal adenocarcinomas(PDACs).We tested FAK variants in 157 tumor samples collected from Chinese patients with pancreatic tumors,and found that FAK^(6/7)was positive in 34(75.6%)of 45 pancreatic NENs,19(47.5%)of 40 pancreatic solid pseudopapillary neoplasms,and 2(2.9%)of 69 PDACs.We further tested FAK splicing variants in breast neuroendocrine carcinoma(BrNECs),and found that FAK^(6/7)was positive in 14(93.3%)of 15 BrNECs but 0 in 23 non-NEC breast cancers.We explored the underlying mechanisms and found that a splicing factor serine/arginine repetitive matrix protein 4(SRRM4)was overexpressed in FAK^(6/7)-positive pancreatic tumors and breast tumors,which promoted the formation of FAK^(6/7)in cells.These results suggested that FAK^(6/7)could be a biomarker of NENs and represent a potential therapeutic target for these orphan diseases.
基金supported by grants from the National Key R&D Program of China grant 2023YFE0101100the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB0630000)+1 种基金the National Natural Science Foundation of China(32225007/32300285)China Postdoctoral Science Foundation(Grant No.2023M733490).
文摘In cuttings,adventitious roots can be regenerated from detached or wounded plant organs,and this process is known as de novo root regeneration.In Arabidopsis thaliana leaf cuttings(Liu et al.2014;Xu 2018),detached A.thaliana leaves are responsive to wound signals and many environmental stimuli,and then synthesize a cer-tain level of auxin,which is transported to regeneration-competent cells(i.e.,procambium and some vascular parenchyma cells near the wound site)to promote cell fate transitions for adventitious root organogenesis(Xu 2018).
基金supported by grants from the National Nature Science Foundation of China(No.82172565,81620108022,81872245,91129303,991729302,81572759,,31900441,82003069,82103571,882002941,82072570,91129733,81502702).
文摘Alcohol consumption contributes to global mortality and cancer development.Acetaldehyde(ACE),the oxidized metabolite of alcohol,is highly reactive towards DNA,resulting in DNA adducts.ACE can be detoxified to acetate by acetaldehyde dehydrogenase type 2(ALDH2).ALDH2 deficiency can lead to ACE accumulation and DNA damage.
基金funded by the China Scholarship Council(CSC)from the Ministry of Education of Chinafunding from the Flemish Government through its support to the Centre for R&D Monitoring(ECOOM)support from the National Laboratory Centre for Library and Information Science at Wuhan University
文摘Interdisciplinary research(IDR)plays a vital role in tackling grand and complex challenges such as COVID-19,which has severe consequences for public health,economy,politics,and society.This study compares several facets of interdisciplinarity that occurred in the research relating to two serious global pandemics in this century,namely SARS and COVID-19,and provides a comprehensive summary of the performance and growth of pandemic-related interdisciplinary research.Generally,the scientific community gathers more multidisciplinary efforts to tackle COVID-19 in comparison to SARS.Firstly,COVID-19 related research from each major field has greater connections with their established expertise and research threads such that they are studying the impact of COVID-19 on their own existing research subjects,while the studies of SARS by different disciplines exhibit less discernable disciplinary characteristics.Secondly,as for the interdisciplinarity observed in the knowledge base of pandemic-related publications,we observe a greater presence of social science knowledge and a more dispersed distribution of knowledge from various disciplines comparing publications on COVID-19 with SARS.Thirdly,regarding interdisciplinarity in research collaboration,COVID-19 publications are on average produced by more interdisciplinary teams than SARS,as measured by the number and diversity of affiliated disciplines of authors.Our discovery on the growth of multidisciplinarity and interdisciplinarity in pandemic-related research signals positive achievement that the scientific community is responding to such a global challenge as a whole and is willing to break down existing disciplinary silos to facilitate the flow of knowledge and breed novelty.
基金supported in part by the National Natural Science Foundation of China(Grant 52277153)in part by the Shandong Province Universities Youth Innovation Technology Support Plan(Grant 2021KJ023).
文摘Surface discharge is a typical fault type in electric power equipment.High temperature in long-term operation can easily lead to ageing of materials,resulting in changes in surface characteristics and surface discharge faults.In this paper,a method of surface discharge identification of silicon rubber(SiR)based on spectral detection technology is presented.The surface discharge spectral characteristics of SiR with different ageing degrees are investigated,and the changes of microphysical and chemical properties and surface insulation properties caused by thermal ageing are analysed.The dynamic evolution of charge during surface discharge is simulated.The experimental results show that the spectral intensity of the surface discharge of the SiR material is mainly concentrated at 350,600 and 750-900 nm bands.The spectral intensity reaches the maximum value when the ageing time is 168 h.With the intensification of ageing,no new characteristic peaks generate in the discharge spectrum,but the proportion of the same characteristic peaks to the overall wavelength is different.The type of discharge material and ageing state are determined by the characteristic light intensity ratio Ib.The evolutionary mechanism of the discharge spectrum is revealed by the variation of flashover voltage,trap charge density,resistivity and other parameters.The simulation results show that the increase of electron density will lead to more intense electron collision,which will release more photons,resulting in enhanced spectral intensity.This work can provide a reference for the detection of surface discharge and the evaluation of ageing state of the equipment inside the high voltage box.
