To explore the molecular mechanisms by which autophagy contributes to pepper's heat tolerance, we previously identified the zinc-finger protein B-BOX 9/CONSTANS-LIKE 13(CaBBX9/CaCOL13) as an interaction partner of...To explore the molecular mechanisms by which autophagy contributes to pepper's heat tolerance, we previously identified the zinc-finger protein B-BOX 9/CONSTANS-LIKE 13(CaBBX9/CaCOL13) as an interaction partner of the autophagy related protein(ATG) CaATG8c, a core component in autophagy. However, the involvement of CaBBX9 in both autophagy and heat tolerance remains unclear. In this study, we further confirmed the interaction between CaBBX9 and CaATG8c and defined the interaction regions of CaBBX9 as CONSTANS, CONSTANS-Like, and TOC1(CCT) domain and the fragment region. The expression of CaBBX9 can be induced by heat treatment. CaBBX9 is co-localized with CaATG8c in the nucleus and exhibits a transcriptional activity. When the expression of CaBBX9 is silenced, the heat tolerance of pepper is enhanced, shown by the decrement of MDA content, H2O2and dead cells accumulation, and relative electrolyte leakage, along with the increment of chlorophyll content and expression level of heat-tolerance-related genes. Overexpression of CaBBX9 in tomatoes displays the opposite effects. Taken together, we demonstrate that CaBBX9 negatively regulates the heat tolerance of peppers by exacerbating oxidative damage and inhibiting the expression of heat-related genes. Our findings provide a new clue for guiding crop breeding for pepper tolerance to heat stress.展开更多
0 INTRODUCTION Continental shale oil is a strategic alternative resource to ensure the safety of national oil supply and improve the level of industrial innovation.China is a large country of continental oil resources...0 INTRODUCTION Continental shale oil is a strategic alternative resource to ensure the safety of national oil supply and improve the level of industrial innovation.China is a large country of continental oil resources,accounting for 90%of the total onshore oil resources;and China is also a major producer of continental oil,accounting for about 93%of the total oil production(Yang et al.,2019;Jia et al.,2018).展开更多
Photonic topological insulators with robust boundary states can enable great applications for optical communication and quantum emission,such as unidirectional waveguide and single-mode laser.However,because of the di...Photonic topological insulators with robust boundary states can enable great applications for optical communication and quantum emission,such as unidirectional waveguide and single-mode laser.However,because of the diffraction limit of light,the physical insight of topological resonance remains unexplored in detail,like the dark line that exists with the crys-talline symmetry-protected topological edge state.Here,we experimentally observe the dark line of the Z_(2)photonic topo-logical insulator in the visible range by photoluminescence and specify its location by cathodoluminescence characteriza-tion,and elucidate its mechanism with the p-d orbital electromagnetic field distribution which calculated by numerical sim-ulation.Our investigation provides a deeper understanding of Z_(2)topological edge states and may have great signific-ance to the design of future on-chip topological devices.展开更多
A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H...A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H37Rv. No obvious antitubercular activities could be observed (MIC > 10 ug/mL). The results are in sharp contrast with the previously reported data.展开更多
The physiology(membrane integrity,intracellular esterase and redox activity)of individual pathogenic bacteria is various in different growing phase,which has a profound significance for food safety testing and control...The physiology(membrane integrity,intracellular esterase and redox activity)of individual pathogenic bacteria is various in different growing phase,which has a profound significance for food safety testing and control.In this work,the aptamers against B.cereus in different growing phase was firstly selected based on whole bacterium-SELEX screening approach.Out of 32 candidate aptamers screened,aptamer B15 and B16 showed relatively high binding affinity with an apparent dissociation constant(Kd value)of 16.134.98 nM and 20.675.23 nM,respectively.A label-free impedance based aptasensor was further fabricated based on the screened aptamer,immobilized onto the GCE/Au surface.With the addition of B.cereus,the electron transfer process was prevented and exhibited a significant decrease in the electron-transfer resistance.Under optimal conditions,the fabricated aptasensor can achieve high sensitive detection of B.cereus as low as 10 cfu/mL.A satisfactory recovery of 90.5%–105.3%was achieved for the B.cereus detection in spiked milk samples,exhibiting its prospect in the sensitive detection of B.cereus in daily life.展开更多
Acoustic metamaterials(AMMs)are a type of artificial materials that make use of appropriate structural designs and exhibit exotic properties not found in natural materials,such as negative effective material parameter...Acoustic metamaterials(AMMs)are a type of artificial materials that make use of appropriate structural designs and exhibit exotic properties not found in natural materials,such as negative effective material parameters(e.g.,bulk modulus,mass density,and refractive index).These interesting properties offer novel means for sound manipulation and thus have drawn a great deal of attention.Over the past two decades,tremendous progress has been made in the fundamental research of AMMs,which has not only promoted the development of modern acoustics but also shown the potential of AMMs for engineering applications.Here,we review recent developments in AMMs with a focus on their future engineering,especially in the most promising fields of sound absorption/isolation,acoustic imaging,cloaking,and so on,furthermore,we outline the opportunities and challenges they are encountering.展开更多
It is well known that in one-dimensional(1D) crystalline insulators,the electric polarization is a manifestation of Berry phase,which can not be quantized by time-reversal symmetry(TRS) as in Hermitian physics TRS doe...It is well known that in one-dimensional(1D) crystalline insulators,the electric polarization is a manifestation of Berry phase,which can not be quantized by time-reversal symmetry(TRS) as in Hermitian physics TRS does not induce any topological phase in one dimension.In this paper we report that even though associated with complex eigenenergies a 1D non-Hermitian insulator obeying only TRS is capable of presenting quantized bulk polarization.The underlying physical reason is unveiled:TRS guarantees the complex energies to come in pair(E,E*),and the corresponding decaying and amplifying wave functions also come in pair and have the same variation rate,hence,giving rise to a stable wannier center.The electron transport is performed by means of charge pumping process,which verifies the physical mechanism above.At last,we discuss the possible experimental implementation of the proposed model by means of twisted-π gauge flux.展开更多
Higher-order topological insulators,originally proposed in quantum condensed matters,have provided a new avenue for localizing and transmitting light in photonic devices.Nontrivial band topology in crystals with certa...Higher-order topological insulators,originally proposed in quantum condensed matters,have provided a new avenue for localizing and transmitting light in photonic devices.Nontrivial band topology in crystals with certain symmetries can host robust topological edge states and lower dimensional topological corner states(TCS),making them a promising platform for photonics applications.Here,we have designed several types of TCS with only two specific C6v-symmetric photonic crystals with various seamless splicing boundaries,where all the supposed TCS with diverse electromagnetic characteristics are visualized via numerical simulations and experimental measurements.More interestingly,we have observed that those TCS overlapping in spectral and spatial space tend to interweaved,inducing spectrum division.Meanwhile,the equivalent corners appear to have TCS with a phase difference,which is critical for directional activation of pseudospin dependence.Our findings demonstrate that coupled TCS with phase difference at different nanocavities can be selectively excited by a chiral source,which indicates that the TCS at this time have pseudospin-dependent properties.We further design a specific splicing structure to prevent coupling between adjacent TCS.This work provides a flexible approach for space-and frequency-division multiplexing in photonic devices.展开更多
The field of topological photonic crystals has attracted growing interest since the inception of optical analog of quantum Hall effect proposed in 2008.Photonic band structures embraced topological phases of matter,ha...The field of topological photonic crystals has attracted growing interest since the inception of optical analog of quantum Hall effect proposed in 2008.Photonic band structures embraced topological phases of matter,have spawned a novel platform for studying topological phase transitions and designing topological optical devices.Here,we present a brief review of topological photonic crystals based on different material platforms,including all-dielectric systems,metallic materials,optical resonators,coupled waveguide systems,and other platforms.Furthermore,this review summarizes recent progress on topological photonic crystals,such as higherorder topological photonic crystals,non-Hermitian photonic crystals,and nonlinear photonic crystals.These studies indicate that topological photonic crystals as versatile platforms have enormous potential applications in maneuvering the flow of light.展开更多
Based on the meteorological monitoring data of Typhoon Nesat and Haitang in Fujian Province in 2017, the data of the typhoon disaster situation and third-party evaluation of typhoon disaster prevention and mitigation ...Based on the meteorological monitoring data of Typhoon Nesat and Haitang in Fujian Province in 2017, the data of the typhoon disaster situation and third-party evaluation of typhoon disaster prevention and mitigation benefit were investigated. By using the mean value anomaly estimation method in the similarity analysis method, it is estimated that typhoon Nesat and Haitang will cause direct economic losses of 0.8 ～ 1.8 billion yuan, and the typhoon disaster risk index evaluation model is used. The disaster risk pre-assessment of Typhoon Nesat and Haitang is carried out. The results of the study and analysis show that the pre-assessment results of Typhoon Nesat and Haitang are basically consistent with the actual disaster situation. The disaster loss was reduced to the minimum. According to the third party evaluation and investigation, it was concluded that the contribution rate of reducing economic benefits was 75% in Fujian Province for preventing and landing double typhoons Nesat and Haitang. Mainly reflected in the ship return to the port to avoid the wind, geological hazards prone to the site construction and cage culture danger removal reinforcement and other links; The contribution rate of reducing casualties is 86, mainly reflected in fishermen disembarkation and personnel transfer to safety emergency shelter and other links. The benefit of this double typhoon disaster prevention and mitigation in Fujian Province is about 0.6 billion yuan to reduce the direct economic loss. According to the investigation, the overall satisfaction of the double typhoon meteorological service is 91.0 points. Typhoon early warning information service convenience satisfaction is 91.4 points, early warning information accuracy satisfaction is 87.2 points, government departments strong anti-Taiwan disaster reduction organization, linkage departments participate in disaster prevention and mitigation high. However, there is a gap between public awareness and participation in typhoon disasters.展开更多
Plants are vulnerable to heat stress,especially during reproductive development.The heat shock response(HSR)in the cytosol and nucleus,as well as the unfolded protein response(UPR)in the endoplasmic reticulum(ER),are ...Plants are vulnerable to heat stress,especially during reproductive development.The heat shock response(HSR)in the cytosol and nucleus,as well as the unfolded protein response(UPR)in the endoplasmic reticulum(ER),are two mechanisms that enable plants to survive heat stress.Excessive heat or ER stresses lead to cell death when the UPR cannot repair stress damage,but the means by which cell survival or death is determined remains unclear.In this study,we used a genome-wide association study(GWAS)to identify that a cluster of five Immune-associated nucleotide-binding protein(IAN)genes(IAN2 to IAN6)is responsible for variation in heat tolerance at the reproductive stage in Arabidopsis thaliana.These IAN genes have both unique and overlapping functions in the negative regulation of heat tolerance,and their loss of function singly or in combination confers increased heat tolerance,measured by a lower number of barren siliques and a higher seedling survival rate under heat.The loss of rice IAN1 gene function also leads to enhanced heat tolerance,suggesting a conserved function of plant IANs.Transcriptome analysis revealed enhanced expression of HSR and UPR genes,as well as reduced cell death,under heat and ER stress in the mutant of IAN6,a major effect member in Arabidopsis.Furthermore,the IAN proteins were found to promote cell death induced by heat stress,ER stress,and cell death-inducing molecules.Thus,the Arabidopsis IAN genes repress heat tolerance,probably through the HSR and UPR and by enhancing the cell death pathway.The IAN2 to IAN6 proteins are partially localized to the ER,suggesting a direct role in the UPR and UPR-mediated cell death.In addition,a natural IAN6 variant from more heat-tolerant Arabidopsis accessions confers greater heat tolerance and induces less cell death compared with the natural variant from less heat-tolerant accessions.The heat-tolerant IAN6 variant is associated with a higher maximum temperature of the warmest month at its collection sites compared with the heat-sensitive variant.Taken together,these results reveal an important role of Arabidopsis IAN2 to IAN6 genes in the regulation of the HSR,UPR,and cell death,and suggest that their natural variations have adaptive functions in heat tolerance.展开更多
The propagation of surface acoustic waves(SAWs) in two-dimensional phononic crystals(PnCs) with and without coupling-enhancement slabs was theoretically investigated using a three-dimensional finite element method.Dif...The propagation of surface acoustic waves(SAWs) in two-dimensional phononic crystals(PnCs) with and without coupling-enhancement slabs was theoretically investigated using a three-dimensional finite element method.Different piezoelectric substrates,for example,lithium niobate(LiNbO_3),gallium nitride(GaN),and aluminium nitride(A1N),were taken into account.Compared to the PnCs without coupling-enhancement slabs,the coupling between each pillar and its nearest neighbor was largely enhanced in the presence of slabs.The bandwidth of the first directional band gap increased markedly compared with its initial value for the PnCs without a slab(within square symmetry).In addition,with increasing thicknesses of the slabs bonded between neighboring pillars,the first directional band-gap and second directional band gap of the PnCs tend to merge.Therefore,the structure with coupling-enhancement slabs can be used as an excellent electrical band elimination filter for most electro-SAW devices,offering a new strategy to realize chip-scale applications in electroacoustic signal processing,optoacoustic modulation,and even SAW microfluidic devices.展开更多
Optical dispersion is an inherent property of all materials in nature. Due to the dispersion of the optical material and the phase accumulation of the light field at different wavelengths, chromatic aberration is inev...Optical dispersion is an inherent property of all materials in nature. Due to the dispersion of the optical material and the phase accumulation of the light field at different wavelengths, chromatic aberration is inevitable in commercial optical lens. When taking pictures by lenses with severe chromatic aberration, the images will look blurred or noticeably colored edges (red, green, blue) around the objects, especially in high-contrast situations. Thus, achromatism, correction of the chromatic aberration, is extremely important in broadband optical applications. There are mainly two approaches in the correction of the chromatic aberration in existing optical systems: combining the refractive lenses with different dispersions or introducing the diffractive optical elements. However, it is still a technical challenge to achieve that goal in the entire visible light band.展开更多
基金supported by a grant from the National Natural Science Foundation of China (32172552, 31572114)the earmarked fund for the China Agriculture Research System (CARS23-G22)。
文摘To explore the molecular mechanisms by which autophagy contributes to pepper's heat tolerance, we previously identified the zinc-finger protein B-BOX 9/CONSTANS-LIKE 13(CaBBX9/CaCOL13) as an interaction partner of the autophagy related protein(ATG) CaATG8c, a core component in autophagy. However, the involvement of CaBBX9 in both autophagy and heat tolerance remains unclear. In this study, we further confirmed the interaction between CaBBX9 and CaATG8c and defined the interaction regions of CaBBX9 as CONSTANS, CONSTANS-Like, and TOC1(CCT) domain and the fragment region. The expression of CaBBX9 can be induced by heat treatment. CaBBX9 is co-localized with CaATG8c in the nucleus and exhibits a transcriptional activity. When the expression of CaBBX9 is silenced, the heat tolerance of pepper is enhanced, shown by the decrement of MDA content, H2O2and dead cells accumulation, and relative electrolyte leakage, along with the increment of chlorophyll content and expression level of heat-tolerance-related genes. Overexpression of CaBBX9 in tomatoes displays the opposite effects. Taken together, we demonstrate that CaBBX9 negatively regulates the heat tolerance of peppers by exacerbating oxidative damage and inhibiting the expression of heat-related genes. Our findings provide a new clue for guiding crop breeding for pepper tolerance to heat stress.
基金PetroChina Shale Oil Major Science and Technology Project(No.2021DJ18)the National High-Level Special Talent Support Plan(the fourth batch)。
文摘0 INTRODUCTION Continental shale oil is a strategic alternative resource to ensure the safety of national oil supply and improve the level of industrial innovation.China is a large country of continental oil resources,accounting for 90%of the total onshore oil resources;and China is also a major producer of continental oil,accounting for about 93%of the total oil production(Yang et al.,2019;Jia et al.,2018).
基金supported by the National Key Research and Development Program of China (grant no.2017YFA0206000)Beijing Natural Science Foundation (grant nos. Z180011)+3 种基金the National Key Research and Development Program of China (grant nos. 2020YFA0211300, 2017YFA0205700, 2019YFA0210203,2018YFA0306200)National Science Foundation of China (grant nos. 12027807, 61521004, 21790364 and 11625418)PKUBaidu Fund Project (grant no.2020BD023)High-performance Computing Platform of Peking University
文摘Photonic topological insulators with robust boundary states can enable great applications for optical communication and quantum emission,such as unidirectional waveguide and single-mode laser.However,because of the diffraction limit of light,the physical insight of topological resonance remains unexplored in detail,like the dark line that exists with the crys-talline symmetry-protected topological edge state.Here,we experimentally observe the dark line of the Z_(2)photonic topo-logical insulator in the visible range by photoluminescence and specify its location by cathodoluminescence characteriza-tion,and elucidate its mechanism with the p-d orbital electromagnetic field distribution which calculated by numerical sim-ulation.Our investigation provides a deeper understanding of Z_(2)topological edge states and may have great signific-ance to the design of future on-chip topological devices.
文摘A series of 2-amino-4H-pyran-3-carbonitrile derivatives were designed and synthesized. Their antitubercular activities were evaluated against autoluminescent M. tuberculosis H37Ra and standard strain M. tuberculosis H37Rv. No obvious antitubercular activities could be observed (MIC > 10 ug/mL). The results are in sharp contrast with the previously reported data.
基金supported by National Natural Science Fund of China(NSFC 32272449)Jiangsu Agriculture Science and Technology Innovation Fund(CX(22)3006)+2 种基金Guangzhou Science and Technology Project(202206010096)the Fundamental Research Funds for the Central Universities(JUSRP622025)Collaborative innovation center of food safety and quality control in Jiangsu Province.
文摘The physiology(membrane integrity,intracellular esterase and redox activity)of individual pathogenic bacteria is various in different growing phase,which has a profound significance for food safety testing and control.In this work,the aptamers against B.cereus in different growing phase was firstly selected based on whole bacterium-SELEX screening approach.Out of 32 candidate aptamers screened,aptamer B15 and B16 showed relatively high binding affinity with an apparent dissociation constant(Kd value)of 16.134.98 nM and 20.675.23 nM,respectively.A label-free impedance based aptasensor was further fabricated based on the screened aptamer,immobilized onto the GCE/Au surface.With the addition of B.cereus,the electron transfer process was prevented and exhibited a significant decrease in the electron-transfer resistance.Under optimal conditions,the fabricated aptasensor can achieve high sensitive detection of B.cereus as low as 10 cfu/mL.A satisfactory recovery of 90.5%–105.3%was achieved for the B.cereus detection in spiked milk samples,exhibiting its prospect in the sensitive detection of B.cereus in daily life.
基金supported by the National Key Research and Development Program of China(2017YFA0303702 and 2018YFA200)the National Natural Science Foundation of China(12172164,11625418,11774297,51732006,11890700,and 51721001)。
文摘Acoustic metamaterials(AMMs)are a type of artificial materials that make use of appropriate structural designs and exhibit exotic properties not found in natural materials,such as negative effective material parameters(e.g.,bulk modulus,mass density,and refractive index).These interesting properties offer novel means for sound manipulation and thus have drawn a great deal of attention.Over the past two decades,tremendous progress has been made in the fundamental research of AMMs,which has not only promoted the development of modern acoustics but also shown the potential of AMMs for engineering applications.Here,we review recent developments in AMMs with a focus on their future engineering,especially in the most promising fields of sound absorption/isolation,acoustic imaging,cloaking,and so on,furthermore,we outline the opportunities and challenges they are encountering.
基金supported by the National Natural Science Foundation of China (Grant Nos.61805141,and 62305113)。
文摘It is well known that in one-dimensional(1D) crystalline insulators,the electric polarization is a manifestation of Berry phase,which can not be quantized by time-reversal symmetry(TRS) as in Hermitian physics TRS does not induce any topological phase in one dimension.In this paper we report that even though associated with complex eigenenergies a 1D non-Hermitian insulator obeying only TRS is capable of presenting quantized bulk polarization.The underlying physical reason is unveiled:TRS guarantees the complex energies to come in pair(E,E*),and the corresponding decaying and amplifying wave functions also come in pair and have the same variation rate,hence,giving rise to a stable wannier center.The electron transport is performed by means of charge pumping process,which verifies the physical mechanism above.At last,we discuss the possible experimental implementation of the proposed model by means of twisted-π gauge flux.
基金National Key Research and Development Program of China(2021YFA1401103,2022YFA1404302)National Natural Science Foundation of China(11834007,11974015,12174189,12304431)Natural Science Foundation of Zhejiang Province(LQ24A040015,LZ22A040008)。
文摘Higher-order topological insulators,originally proposed in quantum condensed matters,have provided a new avenue for localizing and transmitting light in photonic devices.Nontrivial band topology in crystals with certain symmetries can host robust topological edge states and lower dimensional topological corner states(TCS),making them a promising platform for photonics applications.Here,we have designed several types of TCS with only two specific C6v-symmetric photonic crystals with various seamless splicing boundaries,where all the supposed TCS with diverse electromagnetic characteristics are visualized via numerical simulations and experimental measurements.More interestingly,we have observed that those TCS overlapping in spectral and spatial space tend to interweaved,inducing spectrum division.Meanwhile,the equivalent corners appear to have TCS with a phase difference,which is critical for directional activation of pseudospin dependence.Our findings demonstrate that coupled TCS with phase difference at different nanocavities can be selectively excited by a chiral source,which indicates that the TCS at this time have pseudospin-dependent properties.We further design a specific splicing structure to prevent coupling between adjacent TCS.This work provides a flexible approach for space-and frequency-division multiplexing in photonic devices.
基金supported by the National Key R&D Program of China(Nos.2018YFA0306200,and 2017YFA0303702)the National Natural Science Foundation of China(Grant Nos.11625418,51732006,and 11890700)as well as the Academic Program Development of Jiangsu Higher Education(PAPD).
文摘The field of topological photonic crystals has attracted growing interest since the inception of optical analog of quantum Hall effect proposed in 2008.Photonic band structures embraced topological phases of matter,have spawned a novel platform for studying topological phase transitions and designing topological optical devices.Here,we present a brief review of topological photonic crystals based on different material platforms,including all-dielectric systems,metallic materials,optical resonators,coupled waveguide systems,and other platforms.Furthermore,this review summarizes recent progress on topological photonic crystals,such as higherorder topological photonic crystals,non-Hermitian photonic crystals,and nonlinear photonic crystals.These studies indicate that topological photonic crystals as versatile platforms have enormous potential applications in maneuvering the flow of light.
基金2017 China Meteorological Bureau typhoon disaster prevention and mitigation benefit evaluation pilot project2018 Fujian Province disaster prevention and mitigation benefit evaluation capacity-building project to provide financial support
文摘Based on the meteorological monitoring data of Typhoon Nesat and Haitang in Fujian Province in 2017, the data of the typhoon disaster situation and third-party evaluation of typhoon disaster prevention and mitigation benefit were investigated. By using the mean value anomaly estimation method in the similarity analysis method, it is estimated that typhoon Nesat and Haitang will cause direct economic losses of 0.8 ～ 1.8 billion yuan, and the typhoon disaster risk index evaluation model is used. The disaster risk pre-assessment of Typhoon Nesat and Haitang is carried out. The results of the study and analysis show that the pre-assessment results of Typhoon Nesat and Haitang are basically consistent with the actual disaster situation. The disaster loss was reduced to the minimum. According to the third party evaluation and investigation, it was concluded that the contribution rate of reducing economic benefits was 75% in Fujian Province for preventing and landing double typhoons Nesat and Haitang. Mainly reflected in the ship return to the port to avoid the wind, geological hazards prone to the site construction and cage culture danger removal reinforcement and other links; The contribution rate of reducing casualties is 86, mainly reflected in fishermen disembarkation and personnel transfer to safety emergency shelter and other links. The benefit of this double typhoon disaster prevention and mitigation in Fujian Province is about 0.6 billion yuan to reduce the direct economic loss. According to the investigation, the overall satisfaction of the double typhoon meteorological service is 91.0 points. Typhoon early warning information service convenience satisfaction is 91.4 points, early warning information accuracy satisfaction is 87.2 points, government departments strong anti-Taiwan disaster reduction organization, linkage departments participate in disaster prevention and mitigation high. However, there is a gap between public awareness and participation in typhoon disasters.
基金This work is supported by the National Science Foundation of China(NSFC)(31700223 and 31670269)the National Science Foundation of the USA(IOS 1353738)+5 种基金Fundamental Research Funds for the Central Universities(FRFCU)(KJQN201807)the International Postdoctoral Exchange Fellowship Program(no.20160048)from the Office of the China Postdoctoral CouncilOpen Funds of the State Key Laboratory of Plant Physiology and Biochemistry(SKLPPBKF1501)Natural Science Foundation of Jiangsu Province,China(BK20180525)the Jiangsu Collaborative Innovation Center for Modern Crop ProductionCyrus Tang Innovation Center for Crop Seed Industry.
文摘Plants are vulnerable to heat stress,especially during reproductive development.The heat shock response(HSR)in the cytosol and nucleus,as well as the unfolded protein response(UPR)in the endoplasmic reticulum(ER),are two mechanisms that enable plants to survive heat stress.Excessive heat or ER stresses lead to cell death when the UPR cannot repair stress damage,but the means by which cell survival or death is determined remains unclear.In this study,we used a genome-wide association study(GWAS)to identify that a cluster of five Immune-associated nucleotide-binding protein(IAN)genes(IAN2 to IAN6)is responsible for variation in heat tolerance at the reproductive stage in Arabidopsis thaliana.These IAN genes have both unique and overlapping functions in the negative regulation of heat tolerance,and their loss of function singly or in combination confers increased heat tolerance,measured by a lower number of barren siliques and a higher seedling survival rate under heat.The loss of rice IAN1 gene function also leads to enhanced heat tolerance,suggesting a conserved function of plant IANs.Transcriptome analysis revealed enhanced expression of HSR and UPR genes,as well as reduced cell death,under heat and ER stress in the mutant of IAN6,a major effect member in Arabidopsis.Furthermore,the IAN proteins were found to promote cell death induced by heat stress,ER stress,and cell death-inducing molecules.Thus,the Arabidopsis IAN genes repress heat tolerance,probably through the HSR and UPR and by enhancing the cell death pathway.The IAN2 to IAN6 proteins are partially localized to the ER,suggesting a direct role in the UPR and UPR-mediated cell death.In addition,a natural IAN6 variant from more heat-tolerant Arabidopsis accessions confers greater heat tolerance and induces less cell death compared with the natural variant from less heat-tolerant accessions.The heat-tolerant IAN6 variant is associated with a higher maximum temperature of the warmest month at its collection sites compared with the heat-sensitive variant.Taken together,these results reveal an important role of Arabidopsis IAN2 to IAN6 genes in the regulation of the HSR,UPR,and cell death,and suggest that their natural variations have adaptive functions in heat tolerance.
基金supported by the National Basic Research Program of China (GrantNos.2013CB632904,and 2013CB63 2702)the National Nature Science Foundation of China(Grant Nos.11134006,11625418,11474158,and 51472114)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20140019)the project funded by the Priority Academic Program Development of Jiangsu Higher Education
文摘The propagation of surface acoustic waves(SAWs) in two-dimensional phononic crystals(PnCs) with and without coupling-enhancement slabs was theoretically investigated using a three-dimensional finite element method.Different piezoelectric substrates,for example,lithium niobate(LiNbO_3),gallium nitride(GaN),and aluminium nitride(A1N),were taken into account.Compared to the PnCs without coupling-enhancement slabs,the coupling between each pillar and its nearest neighbor was largely enhanced in the presence of slabs.The bandwidth of the first directional band gap increased markedly compared with its initial value for the PnCs without a slab(within square symmetry).In addition,with increasing thicknesses of the slabs bonded between neighboring pillars,the first directional band-gap and second directional band gap of the PnCs tend to merge.Therefore,the structure with coupling-enhancement slabs can be used as an excellent electrical band elimination filter for most electro-SAW devices,offering a new strategy to realize chip-scale applications in electroacoustic signal processing,optoacoustic modulation,and even SAW microfluidic devices.
基金support from the National Key Research and Development Program of China(NKRDP)(2018YFA0306200 and 2017YFA0303702)the National Natural Science Foundation of China(NNSFC)(11625418 and 51732006)
文摘Optical dispersion is an inherent property of all materials in nature. Due to the dispersion of the optical material and the phase accumulation of the light field at different wavelengths, chromatic aberration is inevitable in commercial optical lens. When taking pictures by lenses with severe chromatic aberration, the images will look blurred or noticeably colored edges (red, green, blue) around the objects, especially in high-contrast situations. Thus, achromatism, correction of the chromatic aberration, is extremely important in broadband optical applications. There are mainly two approaches in the correction of the chromatic aberration in existing optical systems: combining the refractive lenses with different dispersions or introducing the diffractive optical elements. However, it is still a technical challenge to achieve that goal in the entire visible light band.
