Cryptic species are commonly misidentified because of high morphological similarities to other species.One group of plants that may harbor large numbers of cryptic species is the quillworts(Isoetes spp.),an ancient aq...Cryptic species are commonly misidentified because of high morphological similarities to other species.One group of plants that may harbor large numbers of cryptic species is the quillworts(Isoetes spp.),an ancient aquatic plant lineage.Although over 350 species of Isoetes have been reported globally,only ten species have been recorded in China.The aim of this study is to better understand Isoetes species diversity in China.For this purpose,we systematically explored the phylogeny and evolution of Isoetes using complete chloroplast genome(plastome)data,spore morphology,chromosome number,genetic structure,and haplotypes of almost all Chinese Isoetes populations.We identified three ploidy levels of Isoetes in Chinaddiploid(2n=22),tetraploid(2n=44),and hexaploid(2n=66).We also found four megaspore and microspore ornamentation types in diploids,six in tetraploids,and three in hexaploids.Phylogenetic analyses confirmed that I.hypsophila as the ancestral group of the genus and revealed that Isoetes diploids,tetraploids,and hexaploids do not form monophyletic clades.Most individual species possess a single genetic structure;however,several samples have conflicting positions on the phylogenetic tree based on SNPs and the tree based on plastome data.All 36 samples shared 22 haplotypes.Divergence time analysis showed that I.hypsophila diverged in the early Eocene(~48.05 Ma),and most other Isoetes species diverged 3-20 Ma.Additionally,different species of Isoetes were found to inhabit different water systems and environments along the Yangtze River.These findings provide new insights into the relationships among Isoetes species in China,where highly similar morphologic populations may harbor many cryptic species.展开更多
The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of tolerance.It directly affects the dimensional accuracy,the grade of carburized an...The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of tolerance.It directly affects the dimensional accuracy,the grade of carburized and hardened gears,and the post-quenching manufacturing costs.In this study,three dimensional numerical models were developed to simulate the carburizing-quenching process of gear based on the multi-field coupling theory using DEFORM software.The results indicated that the ununiform cooling rate of the gear caused by the asymmetry of the web structure would result in the ununiform distribution of martensite,leading to the large runout value at the end face of the gear.Therefore,a novel method was proposed to minimize the heat treatment induced runout value.It was found that the heat treatment induced runout value could be effectively controlled by the addition of a compensation ring and the support of a rod structure.Further experiments showed that the average runout value of the gear end face before and after the proposed heat treatment method were about 0.023 mm and 0.059 mm respectively,which was in good agreement with the simulated results.The novel approach proposed in this study led to a reduction of the gear runout value by 70.0%‒76.9%compared to that of the original heat treatment process,which may serve as a practical and economical way to predict and minimize the heat treatment induced distortion in drive gear.展开更多
BACKGROUND Azathioprine(AZA)and its close analog 6-mercaptopurine are thiopurines widely used in the treatment of patients with cancer,organ transplantation,and autoimmune or inflammatory diseases,including systemic l...BACKGROUND Azathioprine(AZA)and its close analog 6-mercaptopurine are thiopurines widely used in the treatment of patients with cancer,organ transplantation,and autoimmune or inflammatory diseases,including systemic lupus erythematosus.Bone marrow inhibition is a common side effect of AZA,and severe bone marrow inhibition is related to decreased thiopurine S-methyltransferase(TPMT)activity.CASE SUMMARY We herein report a patient with proliferative lupus nephritis who was using AZA for maintenance therapy,had no common TPMT pathogenic site mutations,and exhibited severe bone marrow inhibition on the 15th day after oral administration.CONCLUSION This report alerts physicians to the fact that even though the TPMT gene has no common pathogenic site mutation,severe myelosuppression may also occur.展开更多
Radiation cross-calibration is an effective method to check and verify theaccuracy and stability of sensor measurements. Satellites with high radiation accuracy areused to calibrate satellites with low radiation accur...Radiation cross-calibration is an effective method to check and verify theaccuracy and stability of sensor measurements. Satellites with high radiation accuracy areused to calibrate satellites with low radiation accuracy. In order to ensure the reliability ofthe radiation cross-calibration method, we propose to obtain the gain and offset of theGaoFen-1 satellite by linear regression after the radiation cross-calibration of the satellitewith low precision and compare with the official coefficient. Finally, we get therelationship between the error in radiation cross-calibration results and side swing angle.The linear correction coefficients of each band are: 0.618, 0.625, 0.512 and 0.474. Theresults show that after the method is corrected by the linear correction coefficient, theerror caused by the side swing angle during the cross-calibration of the orbital radiation isreduced. The accuracy of radiation cross-calibration is improved, the frequency ofcalibration is improved and the requirements of remote sensing applications in the newera are adapted.展开更多
A highly site-selective intermolecular trifluoromethylimination of activated and unactivated olefins was reported under transition-metal-and photosensitizer-free conditions.This newly developed strategy provides strai...A highly site-selective intermolecular trifluoromethylimination of activated and unactivated olefins was reported under transition-metal-and photosensitizer-free conditions.This newly developed strategy provides straightforward and efficient access to diverse value-added vicinal trifluoromethyl amines without resorting to the pre-functionalized reagents.Mechanistic experiments demonstrate that the approach proceeded through CF_(3)and iminyl two-radicals process,which were generated directly from commercially available benzophenone imine in a novel electron-donor mode via a SET process activated by the bifunctional hypervalent iodine reagents.The synthetic potential of the protocols was further showcased via the condensation/amination sequential cascade,and transformations to accessβ-CF_(3)primary amines.展开更多
A strategy for the synthesis ofα-carboline derivatives from indole-3-carboxaldehydes and 3-aminocyclohex-2-enones under metal-free conditions has been developed.The combination use of phenyliodine(Ⅲ)diacetate(PIDA)a...A strategy for the synthesis ofα-carboline derivatives from indole-3-carboxaldehydes and 3-aminocyclohex-2-enones under metal-free conditions has been developed.The combination use of phenyliodine(Ⅲ)diacetate(PIDA)and benzoic acid could significantly facilitate the corresponding[3+3]annulation process.This newly developed strategy featured unextraordinary chemoselectivity,good functional group tolerance and the preservation of the carbonyl group of the ketone substrates,which offers the possibility for further transformation of the products.展开更多
Dual-comb spectroscopy(DCS) is a powerful tool in molecular spectroscopy benefiting from the advantages of high resolution and short measurement time. The recently developed soliton microcomb(SMC) can potentially tran...Dual-comb spectroscopy(DCS) is a powerful tool in molecular spectroscopy benefiting from the advantages of high resolution and short measurement time. The recently developed soliton microcomb(SMC) can potentially transfer the dual-comb method to an on-chip platform. In this paper, we demonstrate DCS using two frequency scanning SMCs, termed scanning dual-microcomb spectroscopy(SDMCS). The two SMCs are generated by an auxiliary-assisted thermal balance scheme, and the pump laser frequency sweeps over one free spectral range of the microresonator(~49 GHz) using a feedback control system. The proposed SDMCS has a spectral resolution of 12.5 MHz, which is determined by the minimum sweeping step of the pump laser. Using this SDMCS system, we perform three types of gas molecule absorption spectroscopy recognition and gas concentration detection.This study paves the way for integrated DCS with a high signal-to-noise ratio, high spectral resolution, and fast acquisition rate.展开更多
Free-space optical(FSO)communication technology is a promising approach to establish a secure wireless link,which has the advantages of excellent directionality,large bandwidth,multiple services,low mass and less powe...Free-space optical(FSO)communication technology is a promising approach to establish a secure wireless link,which has the advantages of excellent directionality,large bandwidth,multiple services,low mass and less power requirements,and easy and fast deployments.Increasing the communication capacity is the perennial goal in both scientific and engineer communities.In this paper,we experimentally demonstrate a Tbit/s parallel FSO communication system using a soliton microcomb as a multiple wavelength laser source.Two communication terminals are installed in two buildings with a straight-line distance of~1 km.102 comb lines are modulated by10 Gbit/s differential phase-shift keying signals and demodulated using a delay-line interferometer.When the transmitted optical power is amplified to 19.8 dBm,42 optical channels have optical signal-to-noise ratios higher than 27 dB and bit error rates less than 1×10^(-9).Our experiment shows the feasibility of a wavelength-division multiplexing FSO communication system which suits the ultra-high-speed wireless transmission application scenarios in future satellite-based communications,disaster recovery,defense,last mile problems in networks and remote sensing,and so on.展开更多
基金This study was supported by the Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization(grant number OC202103)the Harbin Normal University Postgraduate Innovation Project(grant number HSDBSCX2021-01)+1 种基金the National Natural Science Foundation of China General Projects(grant number 32170216)the Hangzhou Science and Technology Development Project(grant number 20201203B113).
文摘Cryptic species are commonly misidentified because of high morphological similarities to other species.One group of plants that may harbor large numbers of cryptic species is the quillworts(Isoetes spp.),an ancient aquatic plant lineage.Although over 350 species of Isoetes have been reported globally,only ten species have been recorded in China.The aim of this study is to better understand Isoetes species diversity in China.For this purpose,we systematically explored the phylogeny and evolution of Isoetes using complete chloroplast genome(plastome)data,spore morphology,chromosome number,genetic structure,and haplotypes of almost all Chinese Isoetes populations.We identified three ploidy levels of Isoetes in Chinaddiploid(2n=22),tetraploid(2n=44),and hexaploid(2n=66).We also found four megaspore and microspore ornamentation types in diploids,six in tetraploids,and three in hexaploids.Phylogenetic analyses confirmed that I.hypsophila as the ancestral group of the genus and revealed that Isoetes diploids,tetraploids,and hexaploids do not form monophyletic clades.Most individual species possess a single genetic structure;however,several samples have conflicting positions on the phylogenetic tree based on SNPs and the tree based on plastome data.All 36 samples shared 22 haplotypes.Divergence time analysis showed that I.hypsophila diverged in the early Eocene(~48.05 Ma),and most other Isoetes species diverged 3-20 Ma.Additionally,different species of Isoetes were found to inhabit different water systems and environments along the Yangtze River.These findings provide new insights into the relationships among Isoetes species in China,where highly similar morphologic populations may harbor many cryptic species.
基金National Key R&D Program of China(Grant No.2019YFB2004700)State Key Laboratory of High Performance Complex Manufacturing of China(Grant No.ZZYJKT2019-08)China Postdoctoral International Exchange Program(Grant No.140050004).
文摘The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of tolerance.It directly affects the dimensional accuracy,the grade of carburized and hardened gears,and the post-quenching manufacturing costs.In this study,three dimensional numerical models were developed to simulate the carburizing-quenching process of gear based on the multi-field coupling theory using DEFORM software.The results indicated that the ununiform cooling rate of the gear caused by the asymmetry of the web structure would result in the ununiform distribution of martensite,leading to the large runout value at the end face of the gear.Therefore,a novel method was proposed to minimize the heat treatment induced runout value.It was found that the heat treatment induced runout value could be effectively controlled by the addition of a compensation ring and the support of a rod structure.Further experiments showed that the average runout value of the gear end face before and after the proposed heat treatment method were about 0.023 mm and 0.059 mm respectively,which was in good agreement with the simulated results.The novel approach proposed in this study led to a reduction of the gear runout value by 70.0%‒76.9%compared to that of the original heat treatment process,which may serve as a practical and economical way to predict and minimize the heat treatment induced distortion in drive gear.
文摘BACKGROUND Azathioprine(AZA)and its close analog 6-mercaptopurine are thiopurines widely used in the treatment of patients with cancer,organ transplantation,and autoimmune or inflammatory diseases,including systemic lupus erythematosus.Bone marrow inhibition is a common side effect of AZA,and severe bone marrow inhibition is related to decreased thiopurine S-methyltransferase(TPMT)activity.CASE SUMMARY We herein report a patient with proliferative lupus nephritis who was using AZA for maintenance therapy,had no common TPMT pathogenic site mutations,and exhibited severe bone marrow inhibition on the 15th day after oral administration.CONCLUSION This report alerts physicians to the fact that even though the TPMT gene has no common pathogenic site mutation,severe myelosuppression may also occur.
基金funded by the National Key Research Program ofChina (No. 2016YFB0502500)Guangxi innovative Development Grand Grant (GuiKeAA18118038)+2 种基金Land Observation Satellite Supporting Platform of National civilspace infrastructureNational Natural Science Foundation of China (No. 41671345)theNanjing University of Information Science and Technology Talent Start-up Fund.
文摘Radiation cross-calibration is an effective method to check and verify theaccuracy and stability of sensor measurements. Satellites with high radiation accuracy areused to calibrate satellites with low radiation accuracy. In order to ensure the reliability ofthe radiation cross-calibration method, we propose to obtain the gain and offset of theGaoFen-1 satellite by linear regression after the radiation cross-calibration of the satellitewith low precision and compare with the official coefficient. Finally, we get therelationship between the error in radiation cross-calibration results and side swing angle.The linear correction coefficients of each band are: 0.618, 0.625, 0.512 and 0.474. Theresults show that after the method is corrected by the linear correction coefficient, theerror caused by the side swing angle during the cross-calibration of the orbital radiation isreduced. The accuracy of radiation cross-calibration is improved, the frequency ofcalibration is improved and the requirements of remote sensing applications in the newera are adapted.
基金Financial support from the National Natural Science Foundation of China(Nos.22201239,22205192 and 22271244)the Hunan Provincial Natural Science Foundation of China(No.2022JJ40429)+2 种基金the Scientific Research Fund of Hunan Provincial Education Department(No.21B0130)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(No.2022C02)the Process Intensification&Green Chemical Engineering Innovation Team Project of Hunan Province。
文摘A highly site-selective intermolecular trifluoromethylimination of activated and unactivated olefins was reported under transition-metal-and photosensitizer-free conditions.This newly developed strategy provides straightforward and efficient access to diverse value-added vicinal trifluoromethyl amines without resorting to the pre-functionalized reagents.Mechanistic experiments demonstrate that the approach proceeded through CF_(3)and iminyl two-radicals process,which were generated directly from commercially available benzophenone imine in a novel electron-donor mode via a SET process activated by the bifunctional hypervalent iodine reagents.The synthetic potential of the protocols was further showcased via the condensation/amination sequential cascade,and transformations to accessβ-CF_(3)primary amines.
基金the National Natural Science Foundation of China(Nos.22271244 and 21871226)the Postgraduate Scientific Research Innovation Project of Hunan Province(Nos.XDCX2021B151 and CX20210638)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(No.2022C02)are gratefully acknowledged.
文摘A strategy for the synthesis ofα-carboline derivatives from indole-3-carboxaldehydes and 3-aminocyclohex-2-enones under metal-free conditions has been developed.The combination use of phenyliodine(Ⅲ)diacetate(PIDA)and benzoic acid could significantly facilitate the corresponding[3+3]annulation process.This newly developed strategy featured unextraordinary chemoselectivity,good functional group tolerance and the preservation of the carbonyl group of the ketone substrates,which offers the possibility for further transformation of the products.
基金supported by the National Key R&D Program of China(Grant No. 2021YFB2800600)National Natural Science Foundation of China (Grant No. 62075238)。
文摘Dual-comb spectroscopy(DCS) is a powerful tool in molecular spectroscopy benefiting from the advantages of high resolution and short measurement time. The recently developed soliton microcomb(SMC) can potentially transfer the dual-comb method to an on-chip platform. In this paper, we demonstrate DCS using two frequency scanning SMCs, termed scanning dual-microcomb spectroscopy(SDMCS). The two SMCs are generated by an auxiliary-assisted thermal balance scheme, and the pump laser frequency sweeps over one free spectral range of the microresonator(~49 GHz) using a feedback control system. The proposed SDMCS has a spectral resolution of 12.5 MHz, which is determined by the minimum sweeping step of the pump laser. Using this SDMCS system, we perform three types of gas molecule absorption spectroscopy recognition and gas concentration detection.This study paves the way for integrated DCS with a high signal-to-noise ratio, high spectral resolution, and fast acquisition rate.
基金National Natural Science Foundation of China(62075238,61875227)National Key Research and Development Program of China(2022YFB2803203)。
文摘Free-space optical(FSO)communication technology is a promising approach to establish a secure wireless link,which has the advantages of excellent directionality,large bandwidth,multiple services,low mass and less power requirements,and easy and fast deployments.Increasing the communication capacity is the perennial goal in both scientific and engineer communities.In this paper,we experimentally demonstrate a Tbit/s parallel FSO communication system using a soliton microcomb as a multiple wavelength laser source.Two communication terminals are installed in two buildings with a straight-line distance of~1 km.102 comb lines are modulated by10 Gbit/s differential phase-shift keying signals and demodulated using a delay-line interferometer.When the transmitted optical power is amplified to 19.8 dBm,42 optical channels have optical signal-to-noise ratios higher than 27 dB and bit error rates less than 1×10^(-9).Our experiment shows the feasibility of a wavelength-division multiplexing FSO communication system which suits the ultra-high-speed wireless transmission application scenarios in future satellite-based communications,disaster recovery,defense,last mile problems in networks and remote sensing,and so on.
