Novel two-dimensional thermoelectric materials have attracted significant attention in the field of thermoelectric due to their low lattice thermal conductivity.A comprehensive understanding of their microscopic struc...Novel two-dimensional thermoelectric materials have attracted significant attention in the field of thermoelectric due to their low lattice thermal conductivity.A comprehensive understanding of their microscopic structures is crucial for driving further the optimization of materials properties and developing novel functional materials.Here,by using in situ scanning tunneling microscopy,we report the atomic layer evolution and surface reconstruction on the cleaved thermoelectric material KCu_(4)Se_(3) for the first time.We clearly revealed each atomic layer,including the naturally cleaved K atomic layer,the intermediate Se^(2-)atomic layer,and the Se^(-)atomic layer that emerges in the thermodynamic-stable state.Departing from the maj ority of studies that predominantly concentrate on macroscopic measurements of the charge transport,our results reveal the coexistence of potassium disorder and complex reconstructed patterns of selenium,which potentially influences charge carrier and lattice dynamics.These results provide direct insight into the surface microstructures and evolution of KCu_(4)Se_(3),and shed useful light on designing functional materials with superior performance.展开更多
As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin o...As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin of P. notoginseng knew very little. This study was performed to determine content and heterogeneity of saponins from P. notoginseng and its mechanisms upon treatments with different concentration levels of As in soil. Plants of P. notoginseng were treated with arsenic [As (V)] at 0, 20, 80, 140, 20 and 260 mg/kg concentration levels which were supplied as sodium arsenate (Na<sub>3</sub>AsO<sub>4</sub>)<sub>.</sub> These experimental plants were grown in shade condition in a greenhouse. Plants were harvested at vigorous vegetative growth and fruit ripening stages, separately. Effects of As treatments on saponin content, and heterogeneity of monomers in the mixtures of notoginesenosides and ginsenosides, enzymatic activity and gene expression level of squalene synthetase were determined for rhizome and main root tissues. Results show that:(1) Of all the As treatments from the lowest to the highest concentration levels, the As content in both rhizome and main roots from As-treated plants was within the standard level for superior products derived from P. notoginseng. The content of notoginsenosides from all tissues except the main roots at fruit ripening stage, was 5% higher than the standard level specified in the Chinese Pharmacopoeia;(2) The treatment of As at 20 mg/kg led to an 3.5% - 183.9% increases in total notoginesenosides content in rhizome and main roots, respectively. Treatments with the highest As concentration at 260 mg/kg<sup> </sup>resulted in a significant decline in total notoginsenosides content, and lower enzymatic activity and gene expression levels of squalene synthetase;(3) Under As treatment conditions, the ratio of Rb1/Rg1 decreased but the ratio of (Rb1 + Rg1)/R1 increased in both rhizomes and main roots. Conclusively, this study demonstrated that low As concentration (20 - 80 mg/kg) treatments resulted in higher notoginsenoside content in P. notoginseng. However, treatments with high As concentrations had an adverse effect. The repression in the synthesis of notoginsenoside and interruption of the conversion process from propanaxadiol into propanaxatriol are responsible for more heterogeneous monomer mixtures and low notoginsenoside content. For plants treated with the highest As concentration of 260 mg/kg, both gene expression and enzymatic activities of squalene synthetase were greatly repressed thus leading to a significantly low saponin content in rhizome and main root tissues.展开更多
One-dimensional(1D)topological insulators are superior for low-dissipation applications owing to the 1D character of surface states where scatterings other than prohibited backscattering are further restricted.Among t...One-dimensional(1D)topological insulators are superior for low-dissipation applications owing to the 1D character of surface states where scatterings other than prohibited backscattering are further restricted.Among the proposed candidates for 1D topological materials,TaNiTe_(5)has attracted intensive attention for its quasi-one-dimensional(quasi-1D)crystalline structure.In this study,we identify the chain-like construction and anisotropic electronic states on TaNiTe_5 surface with scanning tunneling microscopy.The electron scatterings are largely suppressed even with chromium impurities deposited on the surface and magnetic field applied normal to the surface,which endows TaNiTe_5 great potential for low-dissipation spintronic applications.展开更多
[Objectives]This study aimed to investigate the effects of lignans from seeds of Herpetospermum caudigerum Wall.(SHC)on expression of TGF-β/Smads in liver tissue of hepatic alcohol-injuried rats,and to explore its pr...[Objectives]This study aimed to investigate the effects of lignans from seeds of Herpetospermum caudigerum Wall.(SHC)on expression of TGF-β/Smads in liver tissue of hepatic alcohol-injuried rats,and to explore its protective mechanism.[Methods]A total of 60 SD rats were randomly divided into six groups.The rats in all the groups except those in the normal group were given with white spirit by gavage for 8 weeks to establish alcoholic liver injury models.After rat models were established successfully,they were administered intragastrically with 400,200 and 100 mg/kg of lignans,respectively.The rats in the normal group were administered intragastrically with 50 mg/kg of silymarin.The administration lasted for 8 weeks,once a day.The changes in the general state,liver tissue pathology and collagen deposition of the rats were observed.The expression of TGF-β,TGF-β1 receptor 1(TβR-I),TGF-β1 receptor 2(TβR-II),Smad2/p-Smad2 and Smad3/p-Smad3 in the hepatic tissue was detected.[Results]The expression levels of TGF-β1,Smad2,p-Smad2,and p-Smad3 significantly declined,and the expression levels of TβR-I,TβR-II and Smad3 did not change significantly in the liver tissue of rats in the lignans groups and the expression levels of TGF-β,Smad2,and p-Smad3 significantly declined.Meanwhile,the expression levels of TβR-I,TβR-II,p-Smad2 and Smad3 did not change significantly in the silymarin group.[Conclusions]The lignans from SHC have significant intervention effects on alcoholic livery injury.The mechanism may be related to the inhibition of hepatic stellate cell(HSC)activation,TGF-βsecretion and p-Smad2,p-Smad3 expression in the signaling pathway.展开更多
[Objectives]To investigate the protective effect and mechanism of Ershiwuwei Songshi Pill on acute alcoholic liver injury in rats.[Methods]Sixty male SD rats were randomly divided into normal control group,model group...[Objectives]To investigate the protective effect and mechanism of Ershiwuwei Songshi Pill on acute alcoholic liver injury in rats.[Methods]Sixty male SD rats were randomly divided into normal control group,model group,polyene phosphatidylcholine(82.08 mg/kg)positive control group and Ershiwuwei Songshi Pill high(180 mg/kg),medium(90 mg/kg)and low(45 mg/kg)dose groups.The rats in each group were given corresponding drugs by intragastric administration for 3 d and fed normally.From the 4th d,all groups except the normal control group were fed with 15 mL/kg liquor(56%vol)for 7 d after 2 h of administration.After the last modeling,the levels of AST,ALT,TC,TG,SOD,GSH in serum and IL-1β,IL-6,TNF-αin liver tissue were measured.The protein expressions of Bax,Bcl-2 and Caspase3 were determined by Western blotting.HE staining was used to observe the pathological changes of liver tissue under light microscope.[Results]Compared with the model group,the body weight and the levels of SOD and GSH in the treatment group were significantly higher than those in the model group;liver index,serum ALT,AST,TC,TG,IL-1β,IL-6 and TNF-αlevels decreased significantly(P<0.01 or P<0.05);HE staining showed that there was a small amount of collagen proliferation and lymphocyte infiltration in connective tissue around the hepatic portal area in the model group,multiple inflammatory foci could be seen in the lobules,and round fat vacuoles could be seen in the cytoplasm;in each administration group,the pathological condition of the liver was mild.[Conclusions]Ershiwuwei Songshi Pill had a certain protective effect on acute alcoholic liver injury in rats,and its mechanism might be related to reducing enzyme,promoting lipid metabolism and anti-inflammation.展开更多
Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is ne...Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is necessary. ‘Zhongshuang 11’, an elite winter rapeseed cultivar, was used in consecutive field experiments during 2010-2012. At initial flowering stage, plants were consecutively sprayed with 0.1 mg/L 2-4-Epibrassinolide(BR) for 3 d. Two hundred sampling pods from different plants were randomly collected to measure seed related indexes with a 4 d interval from 7 to 47 d after peak anthesis (DAPA).Seed color turned light brown at 31 or 35 DAPA after BR treatment, seed dry weight (DWT)was increased while seed moisture content (SMC) was decreased during seed development.DWT almost reached the maximum value when SMC was 33.20% at 31 DAPA in 2010-2011 and 35.29% at 35 DAPA in 2011-2012 growing season after BR treatment. Similarly,the maximum values of standard germination test (SGT), accelerated aging test (AAT)and cold test (CT) were observed at 31 or 35 DAPA after BR treatment respectively. The high yield and seed oil content appeared at 31 or 35 DAPA accompanied with rapid decrease in total non-structural carbohydrate (TNC) in stems and leaves. Our study indicated that BR application advanced maturity of winter rapeseed by 4 to 8 days.展开更多
The thermal phonon transport is a key matter for heat managing in materials science which is crucial for device miniaturization and power density increase. Herein, we report the synthesis, structure and characterizati...The thermal phonon transport is a key matter for heat managing in materials science which is crucial for device miniaturization and power density increase. Herein, we report the synthesis, structure and characterization of a new compound, Cs2Ge3Ga6Se14, with a unique anisotropic structure simultaneously containing Ge^3+ and Ge^2+ that adopt(Ge1)2^3+ Se6 dimer or(Ge2)^2+Se6 octahedron, respectively. The thermal conductivity was measured to be 0.57–0.48 W m^-1 K^-1 from 323 to 773 K, the lowest value among all the known Ge-containing compounds, approaching its glass limit according to the Cahill’s formulation. More importantly, we discover for the first time that the vibration uncoupling of Ge with different valence states hinders the effective thermal energy transport between the(Ge1)2^3+ Se6 dimer and(Ge2)^2+Se6 octahedron, and consequently lowers the thermal conductivity. In addition, we propose a structure factor f = sin(180) ×d/l(i =A, B)iGe Qi, with which a structure map of the Cs2 Ge3 M6 Q14 family is given.展开更多
Kiwifruit is a recently domesticated horticultural fruit crop with substantial economic and nutritional value,especially because of the high content of vitamin C in its fruit.In this study,we de novo assembled two tel...Kiwifruit is a recently domesticated horticultural fruit crop with substantial economic and nutritional value,especially because of the high content of vitamin C in its fruit.In this study,we de novo assembled two telomere-to-telomere kiwifruit genomes from Actinidia chinensis var.‘Donghong’(DH)and Actinidia latifolia‘Kuoye’(KY),with total lengths of 608327852 and 640561626 bp for 29 chromosomes,respectively.With a burst of structural variants involving inversion,translocations,and duplications within 8.39 million years,the metabolite content of DH and KY exhibited differences in saccharides,lignans,and vitamins.A regulatory ERF098 transcription factor family has expanded in KY and Actinidia eriantha,both of which have ultra-high vitamin C content.With each assembly phased into two complete haplotypes,we identified allelic variations between two sets of haplotypes,leading to protein sequence variations in 26494 and 27773 gene loci and allele-specific expression of 4687 and 12238 homozygous gene pairs.Synchronized metabolome and transcriptome changes during DH fruit development revealed the same dynamic patterns in expression levels and metabolite contents;free fatty acids and flavonols accumulated in the early stages,but sugar substances and amino acids accumulated in the late stages.The AcSWEET9b gene that exhibits allelic dominance was further identified to positively correlate with high sucrose content in fruit.Compared with wild varieties and other Actinidia species,AcSWEET9b promoters were selected in red-flesh kiwifruits that have increased fruit sucrose content,providing a possible explanation on why red-flesh kiwifruits are sweeter.Collectively,these two gap-free kiwifruit genomes provide a valuable genetic resource for investigating domestication mechanisms and genome-based breeding of kiwifruit.展开更多
To better understand waterlogging effect on leaf senescence in winter rapseed (Brassica napus L.) during flowering stage, experiments were designed to explore foliar K application influences on adverse effects of wate...To better understand waterlogging effect on leaf senescence in winter rapseed (Brassica napus L.) during flowering stage, experiments were designed to explore foliar K application influences on adverse effects of waterlogging stress. Winter rapeseed was sprayed with K after waterlogging at initial flowering stage. Results indicated that waterlogging significantly decreased leaf net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr). It also declined maximum quantum yield of PS II (Fv/Fm), quantum yield of electron transport (ΦPS II) and photochemical quenching (qP), but increased leaf non-photochemical quenching (NPQ) and minimal fluorescence (Fo). Interestingly, exogenous application of K significantly alleviated waterlogging-induced photosynthesis inhibition. Foliar K application increased RuBisCO activation, chlorophyll and soluble protein contents, while significantly decreased MDA content under waterlogging stress. Moreover, K supplementation improved accumulation of K+, Ca2+, Mg2+, N, Zn2+, Mn2+, Fe2+ in leaves. In general, foliar K application is effective inalleviating deleterious effects of waterlogging stress and delays leaf senescence of winter rapeseed.展开更多
AM1(ABA-mimicking ligand)is a newly identified signaling molecule for plants during drought tolerance.To investigate the potential role of AM1 in response of rapeseed to drought stress,we conducted experiments by grow...AM1(ABA-mimicking ligand)is a newly identified signaling molecule for plants during drought tolerance.To investigate the potential role of AM1 in response of rapeseed to drought stress,we conducted experiments by growing rapeseed plants under different levels of drought stress with or without applying AM1 or ABA in a rain shelter.The results indicated that drought significantly inhibited rapeseed growth by damaging the photosyn-thesis system,increasing active oxygen accumulation,destroying the oxidative system,and worsening membrane lipid peroxidation.Exogenously applied AM1 and ABA both relieved the damage to rapeseed that was induced by drought stress.Compared with the drought-treated rapeseed,the AM1 treatment significantly improved plant height,number of greelp leaves,root collar thickness,leaf area,dry matter weight,and root cap ratios of rapeseed.In addition,Pn,Gs,Ci,Tr were significantly increased by the AM1 treatment.The AM1 treatment also alleviated the drought induced reductions in Fv/Fm,ΦPSII,qN and ETR;induced an increase in NPQ;and resulted in decreased active oxygen accumulation and membrane lipid peroxidation.Although the ABA treatment relieved photosynthetic fluorescence and antioxidation system parameters to some extent,the effect was inferior to AM1 treatment.Yield under AM1 treatment was higher than that under ABA treatment but was still far lower than that of normal water supply control.In summary,AM1 is functionally similar to ABA in terms of drought relief and regulation,moreover has a better effect.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12374196,92165201,11634011,and 22109153)the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0302800)+4 种基金the CAS Project for Young Scientists in Basic Research (Grant No.YSBR-046)the Fundamental Research Funds for the Central Universities (Grant Nos.WK3510000006 and WK3430000003)the Fund of Anhui Initiative in Quantum Information Technologies (Grant No.AHY170000)the University Synergy Innovation Program of Anhui Province,China (Grant No.GXXT-2022-008)the National Synchrotron Radiation Laboratory Joint Funds of University of Science and Technology of China (Grant No.KY2060000241)。
文摘Novel two-dimensional thermoelectric materials have attracted significant attention in the field of thermoelectric due to their low lattice thermal conductivity.A comprehensive understanding of their microscopic structures is crucial for driving further the optimization of materials properties and developing novel functional materials.Here,by using in situ scanning tunneling microscopy,we report the atomic layer evolution and surface reconstruction on the cleaved thermoelectric material KCu_(4)Se_(3) for the first time.We clearly revealed each atomic layer,including the naturally cleaved K atomic layer,the intermediate Se^(2-)atomic layer,and the Se^(-)atomic layer that emerges in the thermodynamic-stable state.Departing from the maj ority of studies that predominantly concentrate on macroscopic measurements of the charge transport,our results reveal the coexistence of potassium disorder and complex reconstructed patterns of selenium,which potentially influences charge carrier and lattice dynamics.These results provide direct insight into the surface microstructures and evolution of KCu_(4)Se_(3),and shed useful light on designing functional materials with superior performance.
文摘As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin of P. notoginseng knew very little. This study was performed to determine content and heterogeneity of saponins from P. notoginseng and its mechanisms upon treatments with different concentration levels of As in soil. Plants of P. notoginseng were treated with arsenic [As (V)] at 0, 20, 80, 140, 20 and 260 mg/kg concentration levels which were supplied as sodium arsenate (Na<sub>3</sub>AsO<sub>4</sub>)<sub>.</sub> These experimental plants were grown in shade condition in a greenhouse. Plants were harvested at vigorous vegetative growth and fruit ripening stages, separately. Effects of As treatments on saponin content, and heterogeneity of monomers in the mixtures of notoginesenosides and ginsenosides, enzymatic activity and gene expression level of squalene synthetase were determined for rhizome and main root tissues. Results show that:(1) Of all the As treatments from the lowest to the highest concentration levels, the As content in both rhizome and main roots from As-treated plants was within the standard level for superior products derived from P. notoginseng. The content of notoginsenosides from all tissues except the main roots at fruit ripening stage, was 5% higher than the standard level specified in the Chinese Pharmacopoeia;(2) The treatment of As at 20 mg/kg led to an 3.5% - 183.9% increases in total notoginesenosides content in rhizome and main roots, respectively. Treatments with the highest As concentration at 260 mg/kg<sup> </sup>resulted in a significant decline in total notoginsenosides content, and lower enzymatic activity and gene expression levels of squalene synthetase;(3) Under As treatment conditions, the ratio of Rb1/Rg1 decreased but the ratio of (Rb1 + Rg1)/R1 increased in both rhizomes and main roots. Conclusively, this study demonstrated that low As concentration (20 - 80 mg/kg) treatments resulted in higher notoginsenoside content in P. notoginseng. However, treatments with high As concentrations had an adverse effect. The repression in the synthesis of notoginsenoside and interruption of the conversion process from propanaxadiol into propanaxatriol are responsible for more heterogeneous monomer mixtures and low notoginsenoside content. For plants treated with the highest As concentration of 260 mg/kg, both gene expression and enzymatic activities of squalene synthetase were greatly repressed thus leading to a significantly low saponin content in rhizome and main root tissues.
基金the National Key R&D Program of China(Grant No.2017YFA0305400)the National Natural Science Foundation of China(Grant No.11227902)。
文摘One-dimensional(1D)topological insulators are superior for low-dissipation applications owing to the 1D character of surface states where scatterings other than prohibited backscattering are further restricted.Among the proposed candidates for 1D topological materials,TaNiTe_(5)has attracted intensive attention for its quasi-one-dimensional(quasi-1D)crystalline structure.In this study,we identify the chain-like construction and anisotropic electronic states on TaNiTe_5 surface with scanning tunneling microscopy.The electron scatterings are largely suppressed even with chromium impurities deposited on the surface and magnetic field applied normal to the surface,which endows TaNiTe_5 great potential for low-dissipation spintronic applications.
基金Graduates'Innovation Project of Southwest Minzu University(CX2016SZ032)National Natural Science Foundation of China(81274168,81573563)Scientific Research Project of Sichuan Provincial Administration of TCM(2016C062).
文摘[Objectives]This study aimed to investigate the effects of lignans from seeds of Herpetospermum caudigerum Wall.(SHC)on expression of TGF-β/Smads in liver tissue of hepatic alcohol-injuried rats,and to explore its protective mechanism.[Methods]A total of 60 SD rats were randomly divided into six groups.The rats in all the groups except those in the normal group were given with white spirit by gavage for 8 weeks to establish alcoholic liver injury models.After rat models were established successfully,they were administered intragastrically with 400,200 and 100 mg/kg of lignans,respectively.The rats in the normal group were administered intragastrically with 50 mg/kg of silymarin.The administration lasted for 8 weeks,once a day.The changes in the general state,liver tissue pathology and collagen deposition of the rats were observed.The expression of TGF-β,TGF-β1 receptor 1(TβR-I),TGF-β1 receptor 2(TβR-II),Smad2/p-Smad2 and Smad3/p-Smad3 in the hepatic tissue was detected.[Results]The expression levels of TGF-β1,Smad2,p-Smad2,and p-Smad3 significantly declined,and the expression levels of TβR-I,TβR-II and Smad3 did not change significantly in the liver tissue of rats in the lignans groups and the expression levels of TGF-β,Smad2,and p-Smad3 significantly declined.Meanwhile,the expression levels of TβR-I,TβR-II,p-Smad2 and Smad3 did not change significantly in the silymarin group.[Conclusions]The lignans from SHC have significant intervention effects on alcoholic livery injury.The mechanism may be related to the inhibition of hepatic stellate cell(HSC)activation,TGF-βsecretion and p-Smad2,p-Smad3 expression in the signaling pathway.
基金Special Fund Project for Basic Scientific Research of Central Universities(2018NZD19)Postgraduate Innovation Project of Southwest Minzu University(CX2018SZ80).
文摘[Objectives]To investigate the protective effect and mechanism of Ershiwuwei Songshi Pill on acute alcoholic liver injury in rats.[Methods]Sixty male SD rats were randomly divided into normal control group,model group,polyene phosphatidylcholine(82.08 mg/kg)positive control group and Ershiwuwei Songshi Pill high(180 mg/kg),medium(90 mg/kg)and low(45 mg/kg)dose groups.The rats in each group were given corresponding drugs by intragastric administration for 3 d and fed normally.From the 4th d,all groups except the normal control group were fed with 15 mL/kg liquor(56%vol)for 7 d after 2 h of administration.After the last modeling,the levels of AST,ALT,TC,TG,SOD,GSH in serum and IL-1β,IL-6,TNF-αin liver tissue were measured.The protein expressions of Bax,Bcl-2 and Caspase3 were determined by Western blotting.HE staining was used to observe the pathological changes of liver tissue under light microscope.[Results]Compared with the model group,the body weight and the levels of SOD and GSH in the treatment group were significantly higher than those in the model group;liver index,serum ALT,AST,TC,TG,IL-1β,IL-6 and TNF-αlevels decreased significantly(P<0.01 or P<0.05);HE staining showed that there was a small amount of collagen proliferation and lymphocyte infiltration in connective tissue around the hepatic portal area in the model group,multiple inflammatory foci could be seen in the lobules,and round fat vacuoles could be seen in the cytoplasm;in each administration group,the pathological condition of the liver was mild.[Conclusions]Ershiwuwei Songshi Pill had a certain protective effect on acute alcoholic liver injury in rats,and its mechanism might be related to reducing enzyme,promoting lipid metabolism and anti-inflammation.
文摘Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is necessary. ‘Zhongshuang 11’, an elite winter rapeseed cultivar, was used in consecutive field experiments during 2010-2012. At initial flowering stage, plants were consecutively sprayed with 0.1 mg/L 2-4-Epibrassinolide(BR) for 3 d. Two hundred sampling pods from different plants were randomly collected to measure seed related indexes with a 4 d interval from 7 to 47 d after peak anthesis (DAPA).Seed color turned light brown at 31 or 35 DAPA after BR treatment, seed dry weight (DWT)was increased while seed moisture content (SMC) was decreased during seed development.DWT almost reached the maximum value when SMC was 33.20% at 31 DAPA in 2010-2011 and 35.29% at 35 DAPA in 2011-2012 growing season after BR treatment. Similarly,the maximum values of standard germination test (SGT), accelerated aging test (AAT)and cold test (CT) were observed at 31 or 35 DAPA after BR treatment respectively. The high yield and seed oil content appeared at 31 or 35 DAPA accompanied with rapid decrease in total non-structural carbohydrate (TNC) in stems and leaves. Our study indicated that BR application advanced maturity of winter rapeseed by 4 to 8 days.
基金supported by the National Natural Science Foundation of China (21975032 and 21571020)the National Key Research and Development Program of China (2018YFA0702100)
文摘The thermal phonon transport is a key matter for heat managing in materials science which is crucial for device miniaturization and power density increase. Herein, we report the synthesis, structure and characterization of a new compound, Cs2Ge3Ga6Se14, with a unique anisotropic structure simultaneously containing Ge^3+ and Ge^2+ that adopt(Ge1)2^3+ Se6 dimer or(Ge2)^2+Se6 octahedron, respectively. The thermal conductivity was measured to be 0.57–0.48 W m^-1 K^-1 from 323 to 773 K, the lowest value among all the known Ge-containing compounds, approaching its glass limit according to the Cahill’s formulation. More importantly, we discover for the first time that the vibration uncoupling of Ge with different valence states hinders the effective thermal energy transport between the(Ge1)2^3+ Se6 dimer and(Ge2)^2+Se6 octahedron, and consequently lowers the thermal conductivity. In addition, we propose a structure factor f = sin(180) ×d/l(i =A, B)iGe Qi, with which a structure map of the Cs2 Ge3 M6 Q14 family is given.
基金supported by the Provincial Technology Innovation Program of Shandongan award from the Natural Science Foundation of Shandong Province(ZR2021ZD30)+2 种基金the Director’s Award from the Peking University Institute of Advanced Agricultural Sciences,the National Top Young Talents Program of Chinathe Boya Postdoctoral Program of Peking University,the National Key R&D Program of China(2019YFD1000200)the Youth Innovation Promotion Association CAS(2018376).
文摘Kiwifruit is a recently domesticated horticultural fruit crop with substantial economic and nutritional value,especially because of the high content of vitamin C in its fruit.In this study,we de novo assembled two telomere-to-telomere kiwifruit genomes from Actinidia chinensis var.‘Donghong’(DH)and Actinidia latifolia‘Kuoye’(KY),with total lengths of 608327852 and 640561626 bp for 29 chromosomes,respectively.With a burst of structural variants involving inversion,translocations,and duplications within 8.39 million years,the metabolite content of DH and KY exhibited differences in saccharides,lignans,and vitamins.A regulatory ERF098 transcription factor family has expanded in KY and Actinidia eriantha,both of which have ultra-high vitamin C content.With each assembly phased into two complete haplotypes,we identified allelic variations between two sets of haplotypes,leading to protein sequence variations in 26494 and 27773 gene loci and allele-specific expression of 4687 and 12238 homozygous gene pairs.Synchronized metabolome and transcriptome changes during DH fruit development revealed the same dynamic patterns in expression levels and metabolite contents;free fatty acids and flavonols accumulated in the early stages,but sugar substances and amino acids accumulated in the late stages.The AcSWEET9b gene that exhibits allelic dominance was further identified to positively correlate with high sucrose content in fruit.Compared with wild varieties and other Actinidia species,AcSWEET9b promoters were selected in red-flesh kiwifruits that have increased fruit sucrose content,providing a possible explanation on why red-flesh kiwifruits are sweeter.Collectively,these two gap-free kiwifruit genomes provide a valuable genetic resource for investigating domestication mechanisms and genome-based breeding of kiwifruit.
文摘To better understand waterlogging effect on leaf senescence in winter rapseed (Brassica napus L.) during flowering stage, experiments were designed to explore foliar K application influences on adverse effects of waterlogging stress. Winter rapeseed was sprayed with K after waterlogging at initial flowering stage. Results indicated that waterlogging significantly decreased leaf net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr). It also declined maximum quantum yield of PS II (Fv/Fm), quantum yield of electron transport (ΦPS II) and photochemical quenching (qP), but increased leaf non-photochemical quenching (NPQ) and minimal fluorescence (Fo). Interestingly, exogenous application of K significantly alleviated waterlogging-induced photosynthesis inhibition. Foliar K application increased RuBisCO activation, chlorophyll and soluble protein contents, while significantly decreased MDA content under waterlogging stress. Moreover, K supplementation improved accumulation of K+, Ca2+, Mg2+, N, Zn2+, Mn2+, Fe2+ in leaves. In general, foliar K application is effective inalleviating deleterious effects of waterlogging stress and delays leaf senescence of winter rapeseed.
基金the Natural Science Foundation of China(No.31771735,No.31971855)the Natural Science Foundation of Hubei Province(No.2019CFB273)Science and Technology Innovation Project from the Chinese Academy of Agricultural Sciences(CAASASTIP-2016-OCRI)。
文摘AM1(ABA-mimicking ligand)is a newly identified signaling molecule for plants during drought tolerance.To investigate the potential role of AM1 in response of rapeseed to drought stress,we conducted experiments by growing rapeseed plants under different levels of drought stress with or without applying AM1 or ABA in a rain shelter.The results indicated that drought significantly inhibited rapeseed growth by damaging the photosyn-thesis system,increasing active oxygen accumulation,destroying the oxidative system,and worsening membrane lipid peroxidation.Exogenously applied AM1 and ABA both relieved the damage to rapeseed that was induced by drought stress.Compared with the drought-treated rapeseed,the AM1 treatment significantly improved plant height,number of greelp leaves,root collar thickness,leaf area,dry matter weight,and root cap ratios of rapeseed.In addition,Pn,Gs,Ci,Tr were significantly increased by the AM1 treatment.The AM1 treatment also alleviated the drought induced reductions in Fv/Fm,ΦPSII,qN and ETR;induced an increase in NPQ;and resulted in decreased active oxygen accumulation and membrane lipid peroxidation.Although the ABA treatment relieved photosynthetic fluorescence and antioxidation system parameters to some extent,the effect was inferior to AM1 treatment.Yield under AM1 treatment was higher than that under ABA treatment but was still far lower than that of normal water supply control.In summary,AM1 is functionally similar to ABA in terms of drought relief and regulation,moreover has a better effect.
