Combining practical engineering projects, this article analyzes the design strategies for the reconstruction and expansion of insufficient clearance sections in highway interchanges. This includes an overview of the p...Combining practical engineering projects, this article analyzes the design strategies for the reconstruction and expansion of insufficient clearance sections in highway interchanges. This includes an overview of the project, a comparison of design options for insufficient clearance in interchanges, and the main design strategies for reconstruction and expansion. It is hoped that this analysis can provide a reference for the design of such road reconstruction and expansion projects.展开更多
This article analyzes the differential settlement of new and old roadbeds after widening and its characteristics based on a highway reconstruction and expansion project case study.The research proposes a subgrade sett...This article analyzes the differential settlement of new and old roadbeds after widening and its characteristics based on a highway reconstruction and expansion project case study.The research proposes a subgrade settlement control standard that states that the maximum differential settlement value should be less than 5 cm when the embankment fill height exceeds 20 m.Similarly,the maximum differential settlement value should be less than 10 cm when the embankment fill height does not exceed 20 m.The findings of the study can provide a useful reference for the design of roadbed widening in highway reconstruction and expansion projects.展开更多
Urban traffic and urban environmental pollution are important issues that must be taken into account in the process of urbanization,especially in China.Modernization has enabled many developed countries in the west to...Urban traffic and urban environmental pollution are important issues that must be taken into account in the process of urbanization,especially in China.Modernization has enabled many developed countries in the west to carry out rational city traffic planning.At the same time,the concept of green transportation has also emerged,integrating low-energy consumption,low pollution,comfort,and safety into urban traffic to effectively solve issues pertaining to traffic and pollution.The concept of green transportation has been widely adopted in China and made popular in many cities,thereby promoting the sustainable development of cities.展开更多
This paper focuses on the route and roadbed pavement design in highway reconstruction and upgrading projects.It discusses the importance of project design for highway reconstruction and upgrading,highlighting key aspe...This paper focuses on the route and roadbed pavement design in highway reconstruction and upgrading projects.It discusses the importance of project design for highway reconstruction and upgrading,highlighting key aspects of route design and roadbed pavement design.The analysis reveals that the main design considerations in these projects include controlling factors of route reconstruction,expansion,and upgrading,as well as route plan design and longitudinal section design combined with roadbed pavement.In roadbed pavement design,it is crucial for designers to thoroughly collect existing data and make reasonable use of the current roadbed and pavement to develop a comprehensive design scheme.This analysis aims to provide a reference for the reasonable design of such projects.展开更多
As an important transportation hub in China,the traffic volume and driving speed are important aspects of expressways.Therefore,the protection requirements for roadbed side slopes are higher,and it is necessary to res...As an important transportation hub in China,the traffic volume and driving speed are important aspects of expressways.Therefore,the protection requirements for roadbed side slopes are higher,and it is necessary to resist rainwater erosion and other damages by protecting the side slopes.Therefore,it is necessary to adopt effective technical means of subgrade protection and support.This paper mainly summarizes the characteristics of highway subgrade slope protection construction and slope protection and support technologies.展开更多
In order to improve the safety of the exit of expressway interchanges,the main problems and influencing factors of interchange exits are analyzed according to the number of traffic accidents at expressway interchange ...In order to improve the safety of the exit of expressway interchanges,the main problems and influencing factors of interchange exits are analyzed according to the number of traffic accidents at expressway interchange exits in China.Some suggestions and countermeasures are then put forward from the aspect of safety technology for future reference.展开更多
Flowering time(heading date)is a critical agronomic trait that determines the yield and regional adaptability of crops.Heading date 1(Hd1)is a central regulator of photoperiodic flowering in rice(Oryza sativa).However...Flowering time(heading date)is a critical agronomic trait that determines the yield and regional adaptability of crops.Heading date 1(Hd1)is a central regulator of photoperiodic flowering in rice(Oryza sativa).However,how the homeostasis of Hd1 protein is achieved is poorly understood.Here,we report that the nuclear autophagy pathway mediates Hd1 degradation in the dark to regulate flowering.Loss of autophagy function results in an accumulation of Hd1 and delays flowering under both short-day and long-day conditions.In the dark,nucleus-localized Hd1 is recognized as a substrate for autophagy and is subjected to vacuolar degradation via the autophagy protein OsATG8.The Hd1-0sATG8 interaction is required for autophagic degradation of Hd1 in the dark.Our study reveals a new mechanism by which Hd1 protein homeostasis is regulated by autophagy to control rice flowering.Our study also indicates that the regulation of flowering by autophagic degradation of Hd1 orthologs may have arisen over the course of mesangiosperm evolution,which would have increased their flexibility and adaptability to the environment by modulating flowering time.展开更多
Glutathione reductase（GR） catalyzes the reduction of glutathione disulfide（GSSG） to reduced glutathione（GSH）and participates in the ascorbate-glutathione cycle, which scavenges H_2O_2. Here, we report that chlor...Glutathione reductase（GR） catalyzes the reduction of glutathione disulfide（GSSG） to reduced glutathione（GSH）and participates in the ascorbate-glutathione cycle, which scavenges H_2O_2. Here, we report that chloroplastic/mitochondrial GR2 is an important regulator of leaf senescence. Seed development of the homozygous gr2 knockout mutant was blocked at the globular stage. Therefore, to investigate the function of GR2 in leaf senescence, we generated transgenic Arabidopsis plants with decreased GR2 using RNAi. The GR2 RNAi plants displayed early onset of age-dependent and darkand H2O2-induced leaf senescence, which was accompanied by the induction of the senescence-related marker genes SAG12 and SAG13. Furthermore, transcriptome analysis revealed that genes related to leaf senescence, oxidative stress, and phytohormone pathways were upregulated directly before senescence in RNAi plants. In addition, H2O2 accumulated to higher levels in RNAi plants than in wild-type plants and the levels of H_2O_2 peaked in RNAi plants directly before the early onset of leaf senescence. RNAi plants showed a greater decrease in GSH/GSSG levels than wild-type plants during leaf development. Our results suggest that GR2 plays an important role in leaf senescence by modulating H_2O_2 and glutathione signaling in Arabidopsis.展开更多
Phytyl-diphosphate, which provides phytyl moieties as a common substrate in both tocopherol and phyllo- quinone biosynthesis, derives from de novo isoprenoid biosynthesis or a salvage pathway via phytol phos- phorylat...Phytyl-diphosphate, which provides phytyl moieties as a common substrate in both tocopherol and phyllo- quinone biosynthesis, derives from de novo isoprenoid biosynthesis or a salvage pathway via phytol phos- phorylation. However, very little is known about the role and origin of the phytyl moiety for phylloquinone biosynthesis. Since VTE6, a phytyl-phosphate kinase, is a key enzyme for phytol phosphorylation, we char- acterized Arabidopsis vte6 mutants to gain insight into the roles of phytyl moieties in phylloquinone biosyn- thesis and of phylloquinone in photosystem I （PSI） biogenesis. The VTE6 knockout mutants vte6-1 and vte6-2 lacked detectable phylloquinone, whereas the phylloquinone content in the VTE6 knockdown mutant vte6-3 was 90% lower than that in wild-type. In vte6 mutants, PSI function was impaired and accu- mulation of the PSI complex was defective. The PSI core subunits PsaA/B were efficiently synthesized and assembled into the PSI complex in vte6-3. However, the degradation rate of PSI subunits in the assembled PSI complex was more rapid in vte6-3 than in wild-type. In vte6-3, PSI was more susceptible to high-light damage than in wild-type. Our results provide the first genetic evidence that the phytol phosphorylation pathway is essential for phylloquinone biosynthesis, and that phylloquinone is required for PSI complex stability.展开更多
To gain a better understanding of the molec-ular mechanisms of photosystem!(PSI)biogenesis,wecharacterized the Arabidopsis thaliana photosystem l bio-genesis factor 2(pbf2)mutant,which lacks PSl complex.PBF2 encodes a...To gain a better understanding of the molec-ular mechanisms of photosystem!(PSI)biogenesis,wecharacterized the Arabidopsis thaliana photosystem l bio-genesis factor 2(pbf2)mutant,which lacks PSl complex.PBF2 encodes a P-class pentatricopeptide repeat(PPR)protein.In the pbf2 mutants,we observed a striking de-crease in the transcript level of only one gene,thechloroplast gene ycf3,which is essential for PSl assembly.Further analysis of ycf3 transcripts showed that PBF2 isspecifically required for the splicing of ycf3 intron 1.Computational prediction of binding sequences and elec-trophoretic mobility shift assays reveal that PBF2 specifi-cally binds to a sequence in ycf3 intron 1.Moreover,we found that PBF2 interacted with two general factors forgroup ll intron splicing CHLOROPLAST RNA SPLICING2-AsSOCIATED FACTOR1(CAF1)and CAF2,and facilitated theassociation of these two factors with ycf3 intron 1.Ourresults suggest that PBF2 is specifically required for thesplicing of ycf3 intron 1 through cooperating with CAF1and CAF2.Our results also suggest that additional proteinsare required to contribute to the specificity of CAF-dependent group ll intron splicing.展开更多
文摘Combining practical engineering projects, this article analyzes the design strategies for the reconstruction and expansion of insufficient clearance sections in highway interchanges. This includes an overview of the project, a comparison of design options for insufficient clearance in interchanges, and the main design strategies for reconstruction and expansion. It is hoped that this analysis can provide a reference for the design of such road reconstruction and expansion projects.
文摘This article analyzes the differential settlement of new and old roadbeds after widening and its characteristics based on a highway reconstruction and expansion project case study.The research proposes a subgrade settlement control standard that states that the maximum differential settlement value should be less than 5 cm when the embankment fill height exceeds 20 m.Similarly,the maximum differential settlement value should be less than 10 cm when the embankment fill height does not exceed 20 m.The findings of the study can provide a useful reference for the design of roadbed widening in highway reconstruction and expansion projects.
文摘Urban traffic and urban environmental pollution are important issues that must be taken into account in the process of urbanization,especially in China.Modernization has enabled many developed countries in the west to carry out rational city traffic planning.At the same time,the concept of green transportation has also emerged,integrating low-energy consumption,low pollution,comfort,and safety into urban traffic to effectively solve issues pertaining to traffic and pollution.The concept of green transportation has been widely adopted in China and made popular in many cities,thereby promoting the sustainable development of cities.
文摘This paper focuses on the route and roadbed pavement design in highway reconstruction and upgrading projects.It discusses the importance of project design for highway reconstruction and upgrading,highlighting key aspects of route design and roadbed pavement design.The analysis reveals that the main design considerations in these projects include controlling factors of route reconstruction,expansion,and upgrading,as well as route plan design and longitudinal section design combined with roadbed pavement.In roadbed pavement design,it is crucial for designers to thoroughly collect existing data and make reasonable use of the current roadbed and pavement to develop a comprehensive design scheme.This analysis aims to provide a reference for the reasonable design of such projects.
文摘As an important transportation hub in China,the traffic volume and driving speed are important aspects of expressways.Therefore,the protection requirements for roadbed side slopes are higher,and it is necessary to resist rainwater erosion and other damages by protecting the side slopes.Therefore,it is necessary to adopt effective technical means of subgrade protection and support.This paper mainly summarizes the characteristics of highway subgrade slope protection construction and slope protection and support technologies.
文摘In order to improve the safety of the exit of expressway interchanges,the main problems and influencing factors of interchange exits are analyzed according to the number of traffic accidents at expressway interchange exits in China.Some suggestions and countermeasures are then put forward from the aspect of safety technology for future reference.
基金supported by the National Key Research and Development Program of China(2020YFA0907602)the National Natural Science Foundation of China(31730102).
文摘Flowering time(heading date)is a critical agronomic trait that determines the yield and regional adaptability of crops.Heading date 1(Hd1)is a central regulator of photoperiodic flowering in rice(Oryza sativa).However,how the homeostasis of Hd1 protein is achieved is poorly understood.Here,we report that the nuclear autophagy pathway mediates Hd1 degradation in the dark to regulate flowering.Loss of autophagy function results in an accumulation of Hd1 and delays flowering under both short-day and long-day conditions.In the dark,nucleus-localized Hd1 is recognized as a substrate for autophagy and is subjected to vacuolar degradation via the autophagy protein OsATG8.The Hd1-0sATG8 interaction is required for autophagic degradation of Hd1 in the dark.Our study reveals a new mechanism by which Hd1 protein homeostasis is regulated by autophagy to control rice flowering.Our study also indicates that the regulation of flowering by autophagic degradation of Hd1 orthologs may have arisen over the course of mesangiosperm evolution,which would have increased their flexibility and adaptability to the environment by modulating flowering time.
基金supported by the National Natural Science Foundation of China(30970218)the State Key Basic Research and Development Plan of China(2015CB150105)
文摘Glutathione reductase（GR） catalyzes the reduction of glutathione disulfide（GSSG） to reduced glutathione（GSH）and participates in the ascorbate-glutathione cycle, which scavenges H_2O_2. Here, we report that chloroplastic/mitochondrial GR2 is an important regulator of leaf senescence. Seed development of the homozygous gr2 knockout mutant was blocked at the globular stage. Therefore, to investigate the function of GR2 in leaf senescence, we generated transgenic Arabidopsis plants with decreased GR2 using RNAi. The GR2 RNAi plants displayed early onset of age-dependent and darkand H2O2-induced leaf senescence, which was accompanied by the induction of the senescence-related marker genes SAG12 and SAG13. Furthermore, transcriptome analysis revealed that genes related to leaf senescence, oxidative stress, and phytohormone pathways were upregulated directly before senescence in RNAi plants. In addition, H2O2 accumulated to higher levels in RNAi plants than in wild-type plants and the levels of H_2O_2 peaked in RNAi plants directly before the early onset of leaf senescence. RNAi plants showed a greater decrease in GSH/GSSG levels than wild-type plants during leaf development. Our results suggest that GR2 plays an important role in leaf senescence by modulating H_2O_2 and glutathione signaling in Arabidopsis.
文摘Phytyl-diphosphate, which provides phytyl moieties as a common substrate in both tocopherol and phyllo- quinone biosynthesis, derives from de novo isoprenoid biosynthesis or a salvage pathway via phytol phos- phorylation. However, very little is known about the role and origin of the phytyl moiety for phylloquinone biosynthesis. Since VTE6, a phytyl-phosphate kinase, is a key enzyme for phytol phosphorylation, we char- acterized Arabidopsis vte6 mutants to gain insight into the roles of phytyl moieties in phylloquinone biosyn- thesis and of phylloquinone in photosystem I （PSI） biogenesis. The VTE6 knockout mutants vte6-1 and vte6-2 lacked detectable phylloquinone, whereas the phylloquinone content in the VTE6 knockdown mutant vte6-3 was 90% lower than that in wild-type. In vte6 mutants, PSI function was impaired and accu- mulation of the PSI complex was defective. The PSI core subunits PsaA/B were efficiently synthesized and assembled into the PSI complex in vte6-3. However, the degradation rate of PSI subunits in the assembled PSI complex was more rapid in vte6-3 than in wild-type. In vte6-3, PSI was more susceptible to high-light damage than in wild-type. Our results provide the first genetic evidence that the phytol phosphorylation pathway is essential for phylloquinone biosynthesis, and that phylloquinone is required for PSI complex stability.
基金This work was supported by the National Natural Science Foundation of China(reference numbers 31730102 and 31401035)the Key Research Plan of Frontier Sciences of the Chinese Academy of Sciences(reference number QYZDJ-SSW-SMC003)。
文摘To gain a better understanding of the molec-ular mechanisms of photosystem!(PSI)biogenesis,wecharacterized the Arabidopsis thaliana photosystem l bio-genesis factor 2(pbf2)mutant,which lacks PSl complex.PBF2 encodes a P-class pentatricopeptide repeat(PPR)protein.In the pbf2 mutants,we observed a striking de-crease in the transcript level of only one gene,thechloroplast gene ycf3,which is essential for PSl assembly.Further analysis of ycf3 transcripts showed that PBF2 isspecifically required for the splicing of ycf3 intron 1.Computational prediction of binding sequences and elec-trophoretic mobility shift assays reveal that PBF2 specifi-cally binds to a sequence in ycf3 intron 1.Moreover,we found that PBF2 interacted with two general factors forgroup ll intron splicing CHLOROPLAST RNA SPLICING2-AsSOCIATED FACTOR1(CAF1)and CAF2,and facilitated theassociation of these two factors with ycf3 intron 1.Ourresults suggest that PBF2 is specifically required for thesplicing of ycf3 intron 1 through cooperating with CAF1and CAF2.Our results also suggest that additional proteinsare required to contribute to the specificity of CAF-dependent group ll intron splicing.
