Roses are important horticultural plants with enormous diversity in flowers and flowering behavior.However,molecular regulation of flowering time variation in roses remains poorly characterized.Here,we report an expan...Roses are important horticultural plants with enormous diversity in flowers and flowering behavior.However,molecular regulation of flowering time variation in roses remains poorly characterized.Here,we report an expansion of the FAR1/FRS-like genes that correlates well with the switch to prostrate-toerect growth of shoots upon flowering in Rosa wichuraiana‘Basye's Thornless'(BT).With the availability of the high-quality chromosome-level genome assembly for BT that we developed recently,we identified 91 RwFAR1/FRS-like genes,a significant expansion in contrast to 52 in Rosa chinensis‘Old Blush’(OB),a founder genotype in modern rose domestication.Rose FAR1/FRS-like proteins feature distinct variation in protein domain structures.The dispersed expansion of RwFAR1/FRS-like genes occurred specifically in clade I and II and is significantly associated with transposon insertion in BT.Most of the RwFAR1/FRS-like genes showed relatively higher expression level than their corresponding orthologs in OB.FAR1/FRS-like genes regulate light-signaling processes,shade avoidance,and flowering time in Arabidopsis thaliana.Therefore,the expansion and duplication of RwFAR1/FRS-like genes,followed by diversification in gene expression,might offer a novel leverage point for further understanding the molecular regulation of the variation in shoot-growth behavior and flowering time in roses.展开更多
Oxygen ions(O;)were implanted into fused silica at a fixed fluence of 1×10^(17) ions/cm^(2) with different ion energies ranging from 10 ke V to 60 ke V.The surface roughness,optical properties,mechanical properti...Oxygen ions(O;)were implanted into fused silica at a fixed fluence of 1×10^(17) ions/cm^(2) with different ion energies ranging from 10 ke V to 60 ke V.The surface roughness,optical properties,mechanical properties and laser damage performance of fused silica were investigated to understand the effect of oxygen ion implantation on laser damage resistance of fused silica.The ion implantation accompanied with sputtering effect can passivate the sub-/surface defects to reduce the surface roughness and improve the surface quality slightly.The implanted oxygen ions can combine with the structural defects(ODCs and E′centers)to reduce the defect densities and compensate the loss of oxygen in fused silica surface under laser irradiation.Furthermore,oxygen ion implantation can reduce the Si-O-Si bond angle and densify the surface structure,thus introducing compressive stress in the surface to strengthen the surface of fused silica.Therefore,the laser induced damage threshold of fused silica increases and the damage growth coefficient decreases when ion energy up to30 ke V.However,at higher ion energy,the sputtering effect is weakened and implantation becomes dominant,which leads to the surface roughness increase slightly.In addition,excessive energy aggravates the breaking of Si-O bonds.At the same time,the density of structural defects increases and the compressive stress decreases.These will degrade the laser laser-damage resistance of fused silica.The results indicate that oxygen ion implantation with appropriate ion energy is helpful to improve the damage resistance capability of fused silica components.展开更多
Temporal information processing in the range of tens to hundreds of milliseconds is critical in many forms of sensory and motor tasks. However, little has been known about the neural mechanisms of temporal information...Temporal information processing in the range of tens to hundreds of milliseconds is critical in many forms of sensory and motor tasks. However, little has been known about the neural mechanisms of temporal information processing. Experimental observations indicate that sensory neurons of the nervous system do not show selective response to temporal properties of external stimuli. On the other hand, temporal selective neurons in the cortex have been reported in many species. Thus, processes which realize the temporal-to-spatial transformation of neuronal activities might be required for temporal information processing. In the present study, we propose a computational model to explore possible roles of electrical synapses in processing the duration of external stimuli. Firstly, we construct a small-scale network with neurons interconnected by electrical synapses in addition to chemical synapses. Basic properties of this small-scale neural network in processing duration information are analyzed. Secondly, a large-scale neural network which is more biologically realistic is further explored. Our results suggest that neural networks with electrical synapses functioning together with chemical synapses can effectively work for the temporal-to-spatial transformation of neuronal activities, and the spatially distributed sequential neural activities can potentially represent temporal information.展开更多
Brassicaceae represents an important plant family from both a scientific and economic perspective.However,genomic features related to the early diversification of this family have not been fully characterized,especial...Brassicaceae represents an important plant family from both a scientific and economic perspective.However,genomic features related to the early diversification of this family have not been fully characterized,especially upon the uplift of the Tibetan Plateau,which was followed by increasing aridity in the Asian interior,intensifying monsoons in Eastern Asia,and significantly fluctuating daily temperatures.Here,we reveal the genomic architecture that accompanied early Brassicaceae diversification by analyzing two high-quality chromosome-level genomes for Meniocus linifolius(Arabodae;clade D)and Tetracme quadricornis(Hesperodae;clade E),together with genomes representing all major Brassicaceae clades and the basal Aethionemeae.We reconstructed an ancestral core Brassicaceae karyotype(CBK)containing 9 pseudochromosomes with 65 conserved syntenic genomic blocks and identified 9702 conserved genes in Brassicaceae.We detected pervasive conflicting phylogenomic signals accompanied by widespread ancient hybridization events,which correlate well with the early divergence of core Brassicaceae.We identified a successive Brassicaceae-specific expansion of the class I TREHALOSE-6-PHOSPHATE SYNTHASE 1(TPS1)gene family,which encodes enzymes with essential regulatory roles in flowering time and embryo development.The TPS1s were mainly randomly amplified,followed by expression divergence.Our results provide fresh insights into historical genomic features coupled with Brassicaceae evolution and offer a potential model for broad-scale studies of adaptive radiation under an ever-changing environment.展开更多
Carbazole-based bi-functional photorefractive polyacrylates were prepared via free radical polymerization and post-azo-coupling reaction. The structure of polymers was characterized by Fourier transform infrared spect...Carbazole-based bi-functional photorefractive polyacrylates were prepared via free radical polymerization and post-azo-coupling reaction. The structure of polymers was characterized by Fourier transform infrared spectroscopy （FTIR） and proton nuclear magnetic resonance （^1H-NMR） spectroscopy. The differential scanning calorimetry （DSC） and the thermal gravimetric analysis （TGA） were used to characterize the thermal property of polymers. The results indicate that though the glass transition temperature （Tg） of polymers increases with increasing the ratio of NLO groups, the polymers with different ratios of NLO groups still all show low glass transition temperatures around 60 ℃, and good thermal stability, which are favorable to the practical application of these polymers. The gel permeation chromatographic （GPC） result indicates that these polymers all have high-molecular-weight which is favorable to the long term stability of the material. Further, these polymers have good solubility in chloroform solvent, and the solutions can easily be fabricated into optically transparent films. Gain coefficients of 75 cm^-1, 185 cm^-1 and 66 cm^-1 can be observed at zero external electric field without any addition agent or pre-poling for polymers P-2, P-3 and P-4 respectively. The different contents of NLO groups result in the different properties of polymers P-2, P-3 and P-4.展开更多
基金This work was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences to J-Y H(XDB31000000)the CAS Pioneer Hundred Talents Program to J-Y H(292015312D11035)and Yunnan Recruitment Program of Experts in Science to J-Y H.
文摘Roses are important horticultural plants with enormous diversity in flowers and flowering behavior.However,molecular regulation of flowering time variation in roses remains poorly characterized.Here,we report an expansion of the FAR1/FRS-like genes that correlates well with the switch to prostrate-toerect growth of shoots upon flowering in Rosa wichuraiana‘Basye's Thornless'(BT).With the availability of the high-quality chromosome-level genome assembly for BT that we developed recently,we identified 91 RwFAR1/FRS-like genes,a significant expansion in contrast to 52 in Rosa chinensis‘Old Blush’(OB),a founder genotype in modern rose domestication.Rose FAR1/FRS-like proteins feature distinct variation in protein domain structures.The dispersed expansion of RwFAR1/FRS-like genes occurred specifically in clade I and II and is significantly associated with transposon insertion in BT.Most of the RwFAR1/FRS-like genes showed relatively higher expression level than their corresponding orthologs in OB.FAR1/FRS-like genes regulate light-signaling processes,shade avoidance,and flowering time in Arabidopsis thaliana.Therefore,the expansion and duplication of RwFAR1/FRS-like genes,followed by diversification in gene expression,might offer a novel leverage point for further understanding the molecular regulation of the variation in shoot-growth behavior and flowering time in roses.
基金Project supported by the National Natural Science Foundation of China(Grant No.12105037)the Key Project of National Natural Science Foundation of China-China Academy of Engineering Physics Joint Foundation(Grant No.U1830204)。
文摘Oxygen ions(O;)were implanted into fused silica at a fixed fluence of 1×10^(17) ions/cm^(2) with different ion energies ranging from 10 ke V to 60 ke V.The surface roughness,optical properties,mechanical properties and laser damage performance of fused silica were investigated to understand the effect of oxygen ion implantation on laser damage resistance of fused silica.The ion implantation accompanied with sputtering effect can passivate the sub-/surface defects to reduce the surface roughness and improve the surface quality slightly.The implanted oxygen ions can combine with the structural defects(ODCs and E′centers)to reduce the defect densities and compensate the loss of oxygen in fused silica surface under laser irradiation.Furthermore,oxygen ion implantation can reduce the Si-O-Si bond angle and densify the surface structure,thus introducing compressive stress in the surface to strengthen the surface of fused silica.Therefore,the laser induced damage threshold of fused silica increases and the damage growth coefficient decreases when ion energy up to30 ke V.However,at higher ion energy,the sputtering effect is weakened and implantation becomes dominant,which leads to the surface roughness increase slightly.In addition,excessive energy aggravates the breaking of Si-O bonds.At the same time,the density of structural defects increases and the compressive stress decreases.These will degrade the laser laser-damage resistance of fused silica.The results indicate that oxygen ion implantation with appropriate ion energy is helpful to improve the damage resistance capability of fused silica components.
文摘Temporal information processing in the range of tens to hundreds of milliseconds is critical in many forms of sensory and motor tasks. However, little has been known about the neural mechanisms of temporal information processing. Experimental observations indicate that sensory neurons of the nervous system do not show selective response to temporal properties of external stimuli. On the other hand, temporal selective neurons in the cortex have been reported in many species. Thus, processes which realize the temporal-to-spatial transformation of neuronal activities might be required for temporal information processing. In the present study, we propose a computational model to explore possible roles of electrical synapses in processing the duration of external stimuli. Firstly, we construct a small-scale network with neurons interconnected by electrical synapses in addition to chemical synapses. Basic properties of this small-scale neural network in processing duration information are analyzed. Secondly, a large-scale neural network which is more biologically realistic is further explored. Our results suggest that neural networks with electrical synapses functioning together with chemical synapses can effectively work for the temporal-to-spatial transformation of neuronal activities, and the spatially distributed sequential neural activities can potentially represent temporal information.
基金supported by the Priority Research Program of the Chinese Academy of Sciences(CAS)(Grant No.XDA0440000 and XDB31000000).
文摘Brassicaceae represents an important plant family from both a scientific and economic perspective.However,genomic features related to the early diversification of this family have not been fully characterized,especially upon the uplift of the Tibetan Plateau,which was followed by increasing aridity in the Asian interior,intensifying monsoons in Eastern Asia,and significantly fluctuating daily temperatures.Here,we reveal the genomic architecture that accompanied early Brassicaceae diversification by analyzing two high-quality chromosome-level genomes for Meniocus linifolius(Arabodae;clade D)and Tetracme quadricornis(Hesperodae;clade E),together with genomes representing all major Brassicaceae clades and the basal Aethionemeae.We reconstructed an ancestral core Brassicaceae karyotype(CBK)containing 9 pseudochromosomes with 65 conserved syntenic genomic blocks and identified 9702 conserved genes in Brassicaceae.We detected pervasive conflicting phylogenomic signals accompanied by widespread ancient hybridization events,which correlate well with the early divergence of core Brassicaceae.We identified a successive Brassicaceae-specific expansion of the class I TREHALOSE-6-PHOSPHATE SYNTHASE 1(TPS1)gene family,which encodes enzymes with essential regulatory roles in flowering time and embryo development.The TPS1s were mainly randomly amplified,followed by expression divergence.Our results provide fresh insights into historical genomic features coupled with Brassicaceae evolution and offer a potential model for broad-scale studies of adaptive radiation under an ever-changing environment.
基金financially supported by the Innovation Foundation of China Academy of Engineering Physics(No.CX08201205)the Development Foundation of China Academy of Engineering Physics(No.2013A0302016)
文摘Carbazole-based bi-functional photorefractive polyacrylates were prepared via free radical polymerization and post-azo-coupling reaction. The structure of polymers was characterized by Fourier transform infrared spectroscopy （FTIR） and proton nuclear magnetic resonance （^1H-NMR） spectroscopy. The differential scanning calorimetry （DSC） and the thermal gravimetric analysis （TGA） were used to characterize the thermal property of polymers. The results indicate that though the glass transition temperature （Tg） of polymers increases with increasing the ratio of NLO groups, the polymers with different ratios of NLO groups still all show low glass transition temperatures around 60 ℃, and good thermal stability, which are favorable to the practical application of these polymers. The gel permeation chromatographic （GPC） result indicates that these polymers all have high-molecular-weight which is favorable to the long term stability of the material. Further, these polymers have good solubility in chloroform solvent, and the solutions can easily be fabricated into optically transparent films. Gain coefficients of 75 cm^-1, 185 cm^-1 and 66 cm^-1 can be observed at zero external electric field without any addition agent or pre-poling for polymers P-2, P-3 and P-4 respectively. The different contents of NLO groups result in the different properties of polymers P-2, P-3 and P-4.
