Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electro...Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas(2DEG)channel.The fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.展开更多
One of the main diseases that adversely impacts the global citrus industry is citrus bacterial canker(CBC),caused by the bacteria Xanthomonas citri subsp.citri(Xcc).Response to CBC is a complex process,with both prote...One of the main diseases that adversely impacts the global citrus industry is citrus bacterial canker(CBC),caused by the bacteria Xanthomonas citri subsp.citri(Xcc).Response to CBC is a complex process,with both proteinDNA as well as protein–protein interactions for the regulatory network.To detect such interactions in CBC resistant regulation,a citrus high-throughput screening system with 203 CBC-inducible transcription factors(TFs),were developed.Screening the upstream regulators of target by yeast-one hybrid(Y1H)methods was also performed.A regulatory module of CBC resistance was identified based on this system.One TF(CsDOF5.8)was explored due to its interactions with the 1-kb promoter fragment of CsPrx25,a resistant gene of CBC involved in reactive oxygen species(ROS)homeostasis regulation.Electrophoretic mobility shift assay(EMSA),dual-LUC assays,as well as transient overexpression of CsDOF5.8,further validated the interactions and transcriptional regulation.The CsDOF5.8–CsPrx25 promoter interaction revealed a complex pathway that governs the regulation of CBC resistance via H2O2homeostasis.The high-throughput Y1H/Y2H screening system could be an efficient tool for studying regulatory pathways or network of CBC resistance regulation.In addition,it could highlight the potential of these candidate genes as targets for efforts to breed CBC-resistant citrus varieties.展开更多
The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by ...The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during treatment.Therefore,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system.The research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>2.Therefore,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably decrease.Subsequently,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental pollution.In short,such an innovative route has guiding significance for drug resistance.展开更多
We have successfully developed cryogen-free dilution refrigerators with medium cooling power that can be applied to quantum experiments. Breakthroughs have been made in some key technologies and components of heat swi...We have successfully developed cryogen-free dilution refrigerators with medium cooling power that can be applied to quantum experiments. Breakthroughs have been made in some key technologies and components of heat switches and dilution units. Our prototype has been running continuously and stably for more than 100 hours below 10 m K, with a minimum temperature of 7.6 m K and a cooling power of 450 μW at 100 m K. At the same time, we have also made progress in the application of dilution refrigerators, such as quantum computing, low-temperature detector, and magnet integration. These indicators and test results indicate good prospects for application in physics, astronomy, and quantum information.展开更多
In this work,a novel one-time-programmable memory unit based on a Schottky-type p-GaN diode is proposed.During the programming process,the junction switches from a high-resistance state to a low-resistance state throu...In this work,a novel one-time-programmable memory unit based on a Schottky-type p-GaN diode is proposed.During the programming process,the junction switches from a high-resistance state to a low-resistance state through Schottky junction breakdown,and the state is permanently preserved.The memory unit features a current ratio of more than 10^(3),a read voltage window of 6 V,a programming time of less than 10^(−4)s,a stability of more than 108 read cycles,and a lifetime of far more than 10 years.Besides,the fabrication of the device is fully compatible with commercial Si-based GaN process platforms,which is of great significance for the realization of low-cost read-only memory in all-GaN integration.展开更多
Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a cent...Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts.展开更多
Recent studies have shown that a 9-hour fast in mice reduces the amount of time spent immobile in the forced swimming test.Howeve r,whether 9-hour fasting has therapeutic effects in female mice with depressive symptom...Recent studies have shown that a 9-hour fast in mice reduces the amount of time spent immobile in the forced swimming test.Howeve r,whether 9-hour fasting has therapeutic effects in female mice with depressive symptoms has not been established.Therefore,in this study,we simulated perimenopausal depression via an ovariectomy in mice,and subjected them to a single 9-hour fasting 7 days later.We found that the ovariectomy increased the time spent immobile in the forced swimming test,inhibited expression of the mammalian target of rapamycin complex 1 signaling pathway in the hippocampus and prefro ntal cortex,and decreased the density of dendritic spines in the hippocampus.The 9-hour acute fasting alleviated the above-mentioned phenomena.Furthermore,all of the antidepressant-like effects of 9-hour fasting were reve rsed by an inhibitor of the mammalian to rget of rapamycin complex 1.Electrophysiology data showed a remarkable increase in long-term potentiation in the hippocampal CA1 of the ovariectomized mice subjected to fasting compared with the findings in the ovariectomized mice not subjected to fasting.These findings show that the antidepressant-like effects of 9-hour fasting may be related to the activation of the mammalian target of the rapamycin complex 1 signaling pathway and synaptic plasticity in the mammalian hippocampus.Thus,fasting may be a potential treatment for depression.展开更多
In this letter,an enhancement-mode(E-mode)GaN p-channel field-effect transistor(p-FET)with a high current den-sity of−4.9 mA/mm based on a O_(3)-Al_(2)O_(3)/HfO_(2)(5/15 nm)stacked gate dielectric was demonstrated on ...In this letter,an enhancement-mode(E-mode)GaN p-channel field-effect transistor(p-FET)with a high current den-sity of−4.9 mA/mm based on a O_(3)-Al_(2)O_(3)/HfO_(2)(5/15 nm)stacked gate dielectric was demonstrated on a p++-GaN/p-GaN/AlN/AlGaN/AlN/GaN/Si heterostructure.Attributed to the p++-GaN capping layer,a good linear ohmic I−V characteristic fea-turing a low-contact resistivity(ρc)of 1.34×10^(−4)Ω·cm^(2) was obtained.High gate leakage associated with the HfO_(2)high-k gate dielectric was effectively blocked by the 5-nm O_(3)-Al_(2)O_(3)insertion layer grown by atomic layer deposition,contributing to a high ION/IOFF ratio of 6×10^(6)and a remarkably reduced subthreshold swing(SS)in the fabricated p-FETs.The proposed structure is compelling for energy-efficient GaN complementary logic(CL)circuits.展开更多
Investigating the spatiotemporal variation of human activity intensity and its determinants is a crucial basis for further revealing the mechanism of human-environment interaction and optimizing the human development ...Investigating the spatiotemporal variation of human activity intensity and its determinants is a crucial basis for further revealing the mechanism of human-environment interaction and optimizing the human development mode.In this study,the human activity intensity on the Qinghai-Tibet Plateau(QTP)from 1990 to 2020 was measured based on the quantitative model of land use data and the actual regional background,and the under-lying natural and socioeconomic determinants were investigated using spatial econometric methods.The results demonstrate that(1)the human activity intensity in QTP has increased by 11.96%,and there are differences in different spatial scales;the areas with high human activity intensity are distributed in the Hehuang Valley where Xining City and its surrounding areas are located,as well as the One-River and Two-River Area where Lhasa City and surrounding areas are located.(2)Human activity intensity has significant positive spatial spillover,suggesting that local changes will cause changes in the same direction in adjacent areas.(3)The human activ-ity intensity in QTP is affected by various determinants.Concerning socioeconomic factors,the economic level has no significant impact on the human activity intensity in QTP,which differs from the general regional law.Both urbanization and traffic conditions have a significant positive effect,and the impact intensity continues to increase.Concerning natural factors,topographic relief has a significant positive effect;the impacts of temper-ature and vegetation coverage have changed from insignificant to a significant positive effect;the impacts of precipitation and river network density have not been verified;there is no linear relationship between altitude and human activity intensity in the entire QTP,while it exists in local regions.Finally,this study proposes three policy implications for the realization of a more harmonious human-environment relationship in QTP.展开更多
As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP...As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange(Citrus sinensis).However,the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated.Here,we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species(ROS)homeostasis in transgenic sweet orange overexpressing CsBZIP40.CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity.CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges.In contrast,its inhibition produces strong resistance to CBC.CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes,resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants.CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance.Overall,our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance.These mechanisms underscore the potential importance of CsBZIP40,CsWRKY43,CsPrx53,and CsSOD13,providing promising strategies for the prevention of CBC.展开更多
Cell death plays an important role in the regulation of inflammation and may be the result of inflammation. The maintenance of tissue homeostasis necessitates both the recognition and removal of invading microbial pat...Cell death plays an important role in the regulation of inflammation and may be the result of inflammation. The maintenance of tissue homeostasis necessitates both the recognition and removal of invading microbial pathogens as well as the clearance of dying cells. In the past few decades, emerging knowledge on cell death and inflammation has enriched our molecular understanding of the signaling pathways that mediate various programs of cell death and multiple types of inflammatory responses. This review provides an overview of the major types of cell death related to inflammation. Modification of cell death pathways is likely to be a logical therapeutic target for inflammatory diseases.展开更多
Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emergi...Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emerging evidence has shown that cell-cell interactions in the lungs play an important regulatory role in the development of acute lung inflammation. However, the underneath mechanisms remain poorly addressed. In this study, we explore a novel function of lung epithelial cells(LEPCs) in regulating the release of exosomes from AMφ following LPS stimulation.Methods: For the in vivo experiments, C57 BL/6 wildtype(WT) mice were treated with lipopolysaccharide(LPS)(2 mg/kg) in 0.2 ml of saline via intratracheal aerosol administration. Bronchoalveolar lavage fluid was collected at 0–24 h after LPS treatment, and exosomes derived from AMφ were measured. For the in vitro studies, LEPCs and bone marrowderived Mφ(BMDM) were isolated from WT or TLR4-/-mice and were then cocultured in the Transwell? system. After coculture for 0–24 h, the BMDM and supernatant were harvested for the measurement of exosomes and cytokines.Results: We demonstrate that LPS induces macrophages(Mφ) to release exosomes, which are then internalized by neighboring Mφ to promote TNF-α expression. The secreted interleukin(IL)-25 from LEPCs downregulates Rab27 a and Rab27 b expression in Mφ, resulting in suppressed exosome release and thereby attenuating exosome-induced TNF-α expression and secretion.Conclusion: These findings reveal a previously unidentified crosstalk pathway between LEPCs and Mφ that negatively regulates the inflammatory responses of Mφ to LPS. Modulating IL-25 signaling and targeting exosome release may present a new therapeutic strategy for the treatment of ALI.展开更多
The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green sol‐vent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the ...The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green sol‐vent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the selective oxidation of benzyl alcohol at room temperature under base‐free aqueous conditions. Experimental observations and density functional theory calculations suggest that ZnO as a support can facilitate the adsorption of benzyl alcohol, which subsequently reacts with the activated oxygen species on the Pt catalyst, producing benzaldehyde. The resulting solid achieves a high conversion(94.1 ± 5.1% in 10 h) of benzyl alcohol and nearly 100% selectivity to benzalde‐hyde with ambient air as the oxidant. In addition, by introducing a small amount of Bi(1.78 wt%) into Pt/ZnO, we can further enhance the activity by 350%.展开更多
The solvent‐free oxidation of benzyl alcohol was studied using supported Pd‐Ni bimetallic nanoparticles.Compared with monometallic Pd,the addition of Ni to Pd was found to be effective in suppressing the nondesired ...The solvent‐free oxidation of benzyl alcohol was studied using supported Pd‐Ni bimetallic nanoparticles.Compared with monometallic Pd,the addition of Ni to Pd was found to be effective in suppressing the nondesired product toluene,thereby enhancing the selectivity towards benzaldehyde.This result was attributed to a dual effect of Ni addition:the weakening of dissociative adsorption of benzyl alcohol and the promotion of oxygen species involved in the oxidation pathway.展开更多
Selective coupling of methyl radicals to produce C_(2) species(C2H4 and C2H6)is a key challenge for oxidative coupling of methane(OCM).In traditional OCM reaction systems,homogeneous transformation of methyl radicals ...Selective coupling of methyl radicals to produce C_(2) species(C2H4 and C2H6)is a key challenge for oxidative coupling of methane(OCM).In traditional OCM reaction systems,homogeneous transformation of methyl radicals in O_(2)‐containing gases are uncontrollable,resulting in limited C_(2) selectivity and yield.Herein,we demonstrate that methyl radicals generated by La_(2)O_(3)at low reaction temperature can selectively couple on the surface of 5 wt%Na2WO4/SiO_(2).The controllable surface coupling against overoxidation barely changes the activity of La_(2)O_(3)but boosts the C_(2)selectivity by three times and achieves a C_(2)yield as high as 10.9%at bed temperature of only 570℃.Structure‐property studies suggest that Na_(2)WO_(4) nanoclusters are the active sites for methyl radical coupling.The strong CH_(3)·affinity of these sites can even endow some methane combustion catalysts with OCM activity.The findings of the surface coupling of methyl radicals open a new direction to develop OCM catalyst.The bifunctional OCM catalyst system,which composes of a methane activation center and a CH_(3)·coupling center,may deliver promising OCM performance at reaction temperatures below the ignition temperature of C2H6 and C2H4(~600℃)and is therefore more controllable,safer,and certainly more attractive as an actual process.展开更多
The lung plays a vital role in maintaining homeostasis,as it is responsible for the exchange of oxygen and carbon dioxide.Pulmonary homeostasis is maintained by a network of tissue-resident cells,including epithelial ...The lung plays a vital role in maintaining homeostasis,as it is responsible for the exchange of oxygen and carbon dioxide.Pulmonary homeostasis is maintained by a network of tissue-resident cells,including epithelial cells,endothelial cells and leukocytes.Myeloid cells of the innate immune system and epithelial cells form a critical barrier in the lung.Recently developed unbiased next generation sequencing(NGS)has revealed cell heterogeneity in the lung with respect to physiology and pathology and has reshaped our knowledge.New phenotypes and distinct gene signatures have been identified,and these new findings enhance the diagnosis and treatment of lung diseases.Here,we present a review of the new NGS findings on myeloid cells in lung development,homeostasis,and lung diseases,including acute lung injury(ALI),lung fibrosis,chronic obstructive pulmonary disease(COPD),and lung cancer.展开更多
A cloud computing based optimal driving method is proposed and its feasibility is validated through a real-world scenario simulation.Based on principles of vehicle dynamics,the driving optimization problem has been fo...A cloud computing based optimal driving method is proposed and its feasibility is validated through a real-world scenario simulation.Based on principles of vehicle dynamics,the driving optimization problem has been formulated into an optimal control problem constrained by traffic rules,directed at achieving lower equivalent fuel consumption and shorter travel time.In order to conveniently specify the constraints and facilitate the application of the dynamic programming(DP)algorithm,the driving optimization problem is transformed into spatial domain and discretized properly.Considering the heavy computational costs of the DP algorithm,a cloud computing based platform structure is proposed to solve the optimal driving problem in real-time.A case study is simulated based on a real-world traffic scenario in Matlab.Simulation results demonstrate that the cloud computing framework is promising toward realizing the real-time energy management for hybrid electric vehicles.展开更多
Here,we demonstrate a photochemical strategy to site-specifically deposit Pd atoms on Au nanoparticles.The high-sensitivity low-energy ion scattering spectra combined with the X-ray photoelectron spectra reveal that t...Here,we demonstrate a photochemical strategy to site-specifically deposit Pd atoms on Au nanoparticles.The high-sensitivity low-energy ion scattering spectra combined with the X-ray photoelectron spectra reveal that the surface electronic structure of Pd can be continuously regulated by tailoring the Pd-to-Au molar ratio and the location of Pd atoms in Au Pd nanoparticles.It is revealed that electron-rich Pd atoms are considerably more active than the net Pd atoms in aerobic alcohol oxidation.Remarkably,the catalyst with the most electron-rich Pd sites(binding energy downshift:1.0 e V)exhibits an extremely high turnover frequency(~500000 h-1 vs 12000 h-1 for that with net Pd atoms)for solvent-free selective oxidation of benzyl alcohol,which is,to the best of our knowledge,the highest value ever reported.Kinetic studies reveal that electron-rich Pd atoms can accelerate the oxidation of benzyl alcohol by facilitating C-H cleavage,as indicated by the significant reduction in the activation energy as compared to net Pd atoms.展开更多
基金supported in part by the National Key Research and Development Program of China under Grant 2022YFB3604400in part by the Youth Innovation Promotion Association of Chinese Academy Sciences(CAS)+4 种基金in part by CAS-Croucher Funding Scheme under Grant CAS22801in part by National Natural Science Foundation of China under Grant 62074161,Grant 62004213,and Grant U20A20208in part by the Beijing Municipal Science and Technology Commission project under Grant Z201100008420009 and Grant Z211100007921018in part by the University of CASin part by IMECAS-HKUST-Joint Laboratory of Microelectronics.
文摘Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron gas(2DEG)channel.The fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.
基金funded by the National Key Research and Development Program of China(2022YFD1201600)the earmarked fund for the China Agriculture Research System(CARS-26)+1 种基金the Fundamental Research Funds for the Central Universities,China(SWU-XDJH202308)the Science and Technology Research Program of Chongqing Municipal Education Commission,China(KJQN202001418)。
文摘One of the main diseases that adversely impacts the global citrus industry is citrus bacterial canker(CBC),caused by the bacteria Xanthomonas citri subsp.citri(Xcc).Response to CBC is a complex process,with both proteinDNA as well as protein–protein interactions for the regulatory network.To detect such interactions in CBC resistant regulation,a citrus high-throughput screening system with 203 CBC-inducible transcription factors(TFs),were developed.Screening the upstream regulators of target by yeast-one hybrid(Y1H)methods was also performed.A regulatory module of CBC resistance was identified based on this system.One TF(CsDOF5.8)was explored due to its interactions with the 1-kb promoter fragment of CsPrx25,a resistant gene of CBC involved in reactive oxygen species(ROS)homeostasis regulation.Electrophoretic mobility shift assay(EMSA),dual-LUC assays,as well as transient overexpression of CsDOF5.8,further validated the interactions and transcriptional regulation.The CsDOF5.8–CsPrx25 promoter interaction revealed a complex pathway that governs the regulation of CBC resistance via H2O2homeostasis.The high-throughput Y1H/Y2H screening system could be an efficient tool for studying regulatory pathways or network of CBC resistance regulation.In addition,it could highlight the potential of these candidate genes as targets for efforts to breed CBC-resistant citrus varieties.
基金supported by the National Natural Science Foundation of China(Nos.22176145,82172612)the State Key Laboratory of Fine Chemicals,Dalian University of Technology(KF 2001)the Fundamental Research Funds for the Central Universities(22120210137).
文摘The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during treatment.Therefore,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system.The research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>2.Therefore,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably decrease.Subsequently,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental pollution.In short,such an innovative route has guiding significance for drug resistance.
基金supported by the Beijing Commission of Science and Technology(Grant No.Z211100004021012)Special Research Assistant Program of the Chinese Academy of Sciences(Grant No.E3VP021RX4)。
文摘We have successfully developed cryogen-free dilution refrigerators with medium cooling power that can be applied to quantum experiments. Breakthroughs have been made in some key technologies and components of heat switches and dilution units. Our prototype has been running continuously and stably for more than 100 hours below 10 m K, with a minimum temperature of 7.6 m K and a cooling power of 450 μW at 100 m K. At the same time, we have also made progress in the application of dilution refrigerators, such as quantum computing, low-temperature detector, and magnet integration. These indicators and test results indicate good prospects for application in physics, astronomy, and quantum information.
基金supported in part by the National Key Research and Development Program of China under Grant 2022YFB3604400in part by the Youth Innovation Promotion Association of Chinese Academy Sciences (CAS)+4 种基金in part by the CAS-Croucher Funding Scheme under Grant CAS22801in part by National Natural Science Foundation of China under Grant 62334012, Grant 62074161, Grant 62004213, Grant U20A20208, and Grant 62304252in part by the Beijing Municipal Science and Technology Commission project under Grant Z201100008420009 and Grant Z211100007921018in part by the University of CASin part by the IMECAS-HKUST-Joint Laboratory of Microelectronics
文摘In this work,a novel one-time-programmable memory unit based on a Schottky-type p-GaN diode is proposed.During the programming process,the junction switches from a high-resistance state to a low-resistance state through Schottky junction breakdown,and the state is permanently preserved.The memory unit features a current ratio of more than 10^(3),a read voltage window of 6 V,a programming time of less than 10^(−4)s,a stability of more than 108 read cycles,and a lifetime of far more than 10 years.Besides,the fabrication of the device is fully compatible with commercial Si-based GaN process platforms,which is of great significance for the realization of low-cost read-only memory in all-GaN integration.
基金supported by the National Natural Science Foundation of China,China(52203066,51973157,51673148 and 51678411)the Science and Technology Plans of Tianjin,China(19PTSYJC00010)+3 种基金China Postdoctoral Science Foundation Grant,China(2019M651047)the Tianjin Research Innovation Project for Postgraduate Students,China(2020YJSB062)the Tianjin Municipal College Student’Innovation And Entrepreneurship Training Program,China(202110058052)the National Innovation and Entrepreneurship Training Program for College Students,China(202110058017)。
文摘Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts.
基金supported by the National Natural Science Foundation of China,No.81871070Jilin Province Medical and Health Talents,No.2020SCZT021Changchun City Science and Technology Development Plan Key Project,No.21ZGY16 (all to BJL)。
文摘Recent studies have shown that a 9-hour fast in mice reduces the amount of time spent immobile in the forced swimming test.Howeve r,whether 9-hour fasting has therapeutic effects in female mice with depressive symptoms has not been established.Therefore,in this study,we simulated perimenopausal depression via an ovariectomy in mice,and subjected them to a single 9-hour fasting 7 days later.We found that the ovariectomy increased the time spent immobile in the forced swimming test,inhibited expression of the mammalian target of rapamycin complex 1 signaling pathway in the hippocampus and prefro ntal cortex,and decreased the density of dendritic spines in the hippocampus.The 9-hour acute fasting alleviated the above-mentioned phenomena.Furthermore,all of the antidepressant-like effects of 9-hour fasting were reve rsed by an inhibitor of the mammalian to rget of rapamycin complex 1.Electrophysiology data showed a remarkable increase in long-term potentiation in the hippocampal CA1 of the ovariectomized mice subjected to fasting compared with the findings in the ovariectomized mice not subjected to fasting.These findings show that the antidepressant-like effects of 9-hour fasting may be related to the activation of the mammalian target of the rapamycin complex 1 signaling pathway and synaptic plasticity in the mammalian hippocampus.Thus,fasting may be a potential treatment for depression.
基金This work was supported in part by the National Key Research and Development Program of China under Grant 2022YFB3604400in part by the Youth Innovation Promotion Association of Chinese Academy Sciences(CAS)+4 种基金in part by CAS-Croucher Funding Scheme under Grant CAS22801in part by National Natural Science Foundation of China under Grant 62074161,Grant 62004213,and Grant U20A20208in part by the Beijing Municipal Science and Technology Commission project under Grant Z201100008420009 and Grant Z211100007921018in part by the University of CASin part by IMECAS-HKUST-Joint Laboratory of Microelectronics.
文摘In this letter,an enhancement-mode(E-mode)GaN p-channel field-effect transistor(p-FET)with a high current den-sity of−4.9 mA/mm based on a O_(3)-Al_(2)O_(3)/HfO_(2)(5/15 nm)stacked gate dielectric was demonstrated on a p++-GaN/p-GaN/AlN/AlGaN/AlN/GaN/Si heterostructure.Attributed to the p++-GaN capping layer,a good linear ohmic I−V characteristic fea-turing a low-contact resistivity(ρc)of 1.34×10^(−4)Ω·cm^(2) was obtained.High gate leakage associated with the HfO_(2)high-k gate dielectric was effectively blocked by the 5-nm O_(3)-Al_(2)O_(3)insertion layer grown by atomic layer deposition,contributing to a high ION/IOFF ratio of 6×10^(6)and a remarkably reduced subthreshold swing(SS)in the fabricated p-FETs.The proposed structure is compelling for energy-efficient GaN complementary logic(CL)circuits.
基金the National Natural Sci-ence Foundation of China(Grant No.42001139)the Second Ti-betan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0406)+1 种基金the National Natural Science Foundation of China(Grant No.42230510)the China Postdoctoral Science Foundation(Grant No.2020M670472).
文摘Investigating the spatiotemporal variation of human activity intensity and its determinants is a crucial basis for further revealing the mechanism of human-environment interaction and optimizing the human development mode.In this study,the human activity intensity on the Qinghai-Tibet Plateau(QTP)from 1990 to 2020 was measured based on the quantitative model of land use data and the actual regional background,and the under-lying natural and socioeconomic determinants were investigated using spatial econometric methods.The results demonstrate that(1)the human activity intensity in QTP has increased by 11.96%,and there are differences in different spatial scales;the areas with high human activity intensity are distributed in the Hehuang Valley where Xining City and its surrounding areas are located,as well as the One-River and Two-River Area where Lhasa City and surrounding areas are located.(2)Human activity intensity has significant positive spatial spillover,suggesting that local changes will cause changes in the same direction in adjacent areas.(3)The human activ-ity intensity in QTP is affected by various determinants.Concerning socioeconomic factors,the economic level has no significant impact on the human activity intensity in QTP,which differs from the general regional law.Both urbanization and traffic conditions have a significant positive effect,and the impact intensity continues to increase.Concerning natural factors,topographic relief has a significant positive effect;the impacts of temper-ature and vegetation coverage have changed from insignificant to a significant positive effect;the impacts of precipitation and river network density have not been verified;there is no linear relationship between altitude and human activity intensity in the entire QTP,while it exists in local regions.Finally,this study proposes three policy implications for the realization of a more harmonious human-environment relationship in QTP.
基金This study was funded by the National Key Research and Development Program of China(2022YFD1201600,2021YFD1600800)National Natural Sciences Foundation of China(32202425)Earmarked Funds for the China Agriculture Research System(CARS-26).
文摘As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange(Citrus sinensis).However,the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated.Here,we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species(ROS)homeostasis in transgenic sweet orange overexpressing CsBZIP40.CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity.CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges.In contrast,its inhibition produces strong resistance to CBC.CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes,resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants.CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance.Overall,our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance.These mechanisms underscore the potential importance of CsBZIP40,CsWRKY43,CsPrx53,and CsSOD13,providing promising strategies for the prevention of CBC.
基金supported by the USA National Institutes of Health Grant R01-HL-079669USA National Institutes of Health Center Grant P50-GM-53789a USA VA Merit Award
文摘Cell death plays an important role in the regulation of inflammation and may be the result of inflammation. The maintenance of tissue homeostasis necessitates both the recognition and removal of invading microbial pathogens as well as the clearance of dying cells. In the past few decades, emerging knowledge on cell death and inflammation has enriched our molecular understanding of the signaling pathways that mediate various programs of cell death and multiple types of inflammatory responses. This review provides an overview of the major types of cell death related to inflammation. Modification of cell death pathways is likely to be a logical therapeutic target for inflammatory diseases.
基金supported by the National Institute of Health Grant(R01-HL-079669 by JF and MAW)the National Institute of Health Grant(R56-HL-123882 by JF)+3 种基金the National Institute of Health Grant(R01HL076179–09 by PW and JF)the VA Merit Award(1I01BX002729 by JF)the National Natural Science Foundation of China(81470262 by JF)the National Institute of Health Grant(R01GM102146 by MJS)
文摘Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emerging evidence has shown that cell-cell interactions in the lungs play an important regulatory role in the development of acute lung inflammation. However, the underneath mechanisms remain poorly addressed. In this study, we explore a novel function of lung epithelial cells(LEPCs) in regulating the release of exosomes from AMφ following LPS stimulation.Methods: For the in vivo experiments, C57 BL/6 wildtype(WT) mice were treated with lipopolysaccharide(LPS)(2 mg/kg) in 0.2 ml of saline via intratracheal aerosol administration. Bronchoalveolar lavage fluid was collected at 0–24 h after LPS treatment, and exosomes derived from AMφ were measured. For the in vitro studies, LEPCs and bone marrowderived Mφ(BMDM) were isolated from WT or TLR4-/-mice and were then cocultured in the Transwell? system. After coculture for 0–24 h, the BMDM and supernatant were harvested for the measurement of exosomes and cytokines.Results: We demonstrate that LPS induces macrophages(Mφ) to release exosomes, which are then internalized by neighboring Mφ to promote TNF-α expression. The secreted interleukin(IL)-25 from LEPCs downregulates Rab27 a and Rab27 b expression in Mφ, resulting in suppressed exosome release and thereby attenuating exosome-induced TNF-α expression and secretion.Conclusion: These findings reveal a previously unidentified crosstalk pathway between LEPCs and Mφ that negatively regulates the inflammatory responses of Mφ to LPS. Modulating IL-25 signaling and targeting exosome release may present a new therapeutic strategy for the treatment of ALI.
基金supported by the National Natural Science Foundation of China (21703050, 21271153, 21373181)China Postdoctoral Science Foun‐dation (512200‐X91701)Special Research Foundation of Young Teachers in Hangzhou Dianzi University (ZX150204307002/032)~~
文摘The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green sol‐vent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the selective oxidation of benzyl alcohol at room temperature under base‐free aqueous conditions. Experimental observations and density functional theory calculations suggest that ZnO as a support can facilitate the adsorption of benzyl alcohol, which subsequently reacts with the activated oxygen species on the Pt catalyst, producing benzaldehyde. The resulting solid achieves a high conversion(94.1 ± 5.1% in 10 h) of benzyl alcohol and nearly 100% selectivity to benzalde‐hyde with ambient air as the oxidant. In addition, by introducing a small amount of Bi(1.78 wt%) into Pt/ZnO, we can further enhance the activity by 350%.
基金supported by National Natural Science Foundation of China(21271153,21373181,21222307,U1402233)Major Research Plan of National Natural Science Foundation of China(91545113)the Fundamental Research Funds for the Central Universities(2014XZZX003-02)~~
文摘The solvent‐free oxidation of benzyl alcohol was studied using supported Pd‐Ni bimetallic nanoparticles.Compared with monometallic Pd,the addition of Ni to Pd was found to be effective in suppressing the nondesired product toluene,thereby enhancing the selectivity towards benzaldehyde.This result was attributed to a dual effect of Ni addition:the weakening of dissociative adsorption of benzyl alcohol and the promotion of oxygen species involved in the oxidation pathway.
文摘Selective coupling of methyl radicals to produce C_(2) species(C2H4 and C2H6)is a key challenge for oxidative coupling of methane(OCM).In traditional OCM reaction systems,homogeneous transformation of methyl radicals in O_(2)‐containing gases are uncontrollable,resulting in limited C_(2) selectivity and yield.Herein,we demonstrate that methyl radicals generated by La_(2)O_(3)at low reaction temperature can selectively couple on the surface of 5 wt%Na2WO4/SiO_(2).The controllable surface coupling against overoxidation barely changes the activity of La_(2)O_(3)but boosts the C_(2)selectivity by three times and achieves a C_(2)yield as high as 10.9%at bed temperature of only 570℃.Structure‐property studies suggest that Na_(2)WO_(4) nanoclusters are the active sites for methyl radical coupling.The strong CH_(3)·affinity of these sites can even endow some methane combustion catalysts with OCM activity.The findings of the surface coupling of methyl radicals open a new direction to develop OCM catalyst.The bifunctional OCM catalyst system,which composes of a methane activation center and a CH_(3)·coupling center,may deliver promising OCM performance at reaction temperatures below the ignition temperature of C2H6 and C2H4(~600℃)and is therefore more controllable,safer,and certainly more attractive as an actual process.
基金the USA National Institutes of Health Grant R01-HL-079669(J.F.)USA National Institutes of Health Grant R01HL076179(J.F.)+2 种基金USA National Institutes of Health Grant R01HL-139547(J.F.)VA Merit Award 1I01BX002729(J.F.)VA BLR&D Award 1IK6BX004211(J.F.).
文摘The lung plays a vital role in maintaining homeostasis,as it is responsible for the exchange of oxygen and carbon dioxide.Pulmonary homeostasis is maintained by a network of tissue-resident cells,including epithelial cells,endothelial cells and leukocytes.Myeloid cells of the innate immune system and epithelial cells form a critical barrier in the lung.Recently developed unbiased next generation sequencing(NGS)has revealed cell heterogeneity in the lung with respect to physiology and pathology and has reshaped our knowledge.New phenotypes and distinct gene signatures have been identified,and these new findings enhance the diagnosis and treatment of lung diseases.Here,we present a review of the new NGS findings on myeloid cells in lung development,homeostasis,and lung diseases,including acute lung injury(ALI),lung fibrosis,chronic obstructive pulmonary disease(COPD),and lung cancer.
基金Supported by the National Nature Science Foundation of China(5177503951861135301)
文摘A cloud computing based optimal driving method is proposed and its feasibility is validated through a real-world scenario simulation.Based on principles of vehicle dynamics,the driving optimization problem has been formulated into an optimal control problem constrained by traffic rules,directed at achieving lower equivalent fuel consumption and shorter travel time.In order to conveniently specify the constraints and facilitate the application of the dynamic programming(DP)algorithm,the driving optimization problem is transformed into spatial domain and discretized properly.Considering the heavy computational costs of the DP algorithm,a cloud computing based platform structure is proposed to solve the optimal driving problem in real-time.A case study is simulated based on a real-world traffic scenario in Matlab.Simulation results demonstrate that the cloud computing framework is promising toward realizing the real-time energy management for hybrid electric vehicles.
文摘Here,we demonstrate a photochemical strategy to site-specifically deposit Pd atoms on Au nanoparticles.The high-sensitivity low-energy ion scattering spectra combined with the X-ray photoelectron spectra reveal that the surface electronic structure of Pd can be continuously regulated by tailoring the Pd-to-Au molar ratio and the location of Pd atoms in Au Pd nanoparticles.It is revealed that electron-rich Pd atoms are considerably more active than the net Pd atoms in aerobic alcohol oxidation.Remarkably,the catalyst with the most electron-rich Pd sites(binding energy downshift:1.0 e V)exhibits an extremely high turnover frequency(~500000 h-1 vs 12000 h-1 for that with net Pd atoms)for solvent-free selective oxidation of benzyl alcohol,which is,to the best of our knowledge,the highest value ever reported.Kinetic studies reveal that electron-rich Pd atoms can accelerate the oxidation of benzyl alcohol by facilitating C-H cleavage,as indicated by the significant reduction in the activation energy as compared to net Pd atoms.