Mesoscale eddies have been suggested to have an impact on biological carbon fixation in the South China Sea （SCS）. However, their overall contribution to primary production during the spring inter-monsoon pe riod is...Mesoscale eddies have been suggested to have an impact on biological carbon fixation in the South China Sea （SCS）. However, their overall contribution to primary production during the spring inter-monsoon pe riod is still unknown. Based on large-scale biological and environmental in situ observations and synchro nous remote sensing data, the distribution patterns of phytoplankton biomass and the primary production, and the role of mesoscale eddies in regulating primary production in different eddy-controlled waters were investigated. The results suggested that the surface chlorophyll a concentrations and water column inte grated primary production （IPP） are significantly higher in cyclonic eddies and lower in the anticyclonic eddies as compared to that in non-eddy waters. Although eddies could affect various environmental factors, such as nutrients, temperature and light availability, nutrient supply is suggested to be the most important one through which mesoscale eddies regulated the distribution patterns of phytoplankton biomass and pri mary production. The estimated IPP in cyclonic and anticyclonic eddies are about 29.5% higher and 16.6% lower than the total average in the whole study area, respectively, indicating that the promotion effect of mesoscale cold eddies on the primary production was much stronger than the inhibition effect of the warm eddies per unit area. Overall, mesoscale eddies are crucial physical processes that affect the biological car bon fixation and the distribution pattern of primary production in the SCS open sea, especially during the spring inter-monsoon period.展开更多
The multitude of airborne point clouds limits the point cloud processing efficiency.Superpoints are grouped based on similar points,which can effectively alleviate the demand for computing resources and improve proces...The multitude of airborne point clouds limits the point cloud processing efficiency.Superpoints are grouped based on similar points,which can effectively alleviate the demand for computing resources and improve processing efficiency.However,existing superpoint segmentation methods focus only on local geometric structures,resulting in inconsistent spectral features of points within a superpoint.Such feature inconsistencies degrade the performance of subsequent tasks.Thus,this study proposes a novel Superpoint Segmentation method that jointly utilizes spatial Geometric and Spectral Information for multispectral point cloud superpoint segmentation(GSI-SS).Specifically,a similarity metric that combines spatial geometry and spectral information is proposed to facilitate the consistency of geometric structures and object attributes within segmented superpoints.Following the formation of the primary superpoints,an intersuperpoint pointexchange mechanism that maximizes feature consistency within the final superpoints is proposed.Experiments are conducted on two real multispectral point cloud datasets,and the proposed method achieved higher recall,precision,F score,and lower global consistency and feature classification errors.The experimental results demonstrate the superiority of the proposed GSI-SS over several state-of-the-art methods.展开更多
In traditional Chinese medicine theory, Panax ginseng and Veratrum nigrum L. is an important incompatible herb pair. Studies on the content variation of main components and the influences on the metabolism in rat inte...In traditional Chinese medicine theory, Panax ginseng and Veratrum nigrum L. is an important incompatible herb pair. Studies on the content variation of main components and the influences on the metabolism in rat intestinal bacteria are useful to understand the mechanism of incompatibility of this herb pairs. In this study, the content variation of ginsenosides and their metaboltic profiles in the extracts of P. ginseng and compatibility of P. ginseng with V. nigrum L. （G-V） were investigated using relative quantitative method of electrospray ionization mass spec- trometry （ESI-MS） and UPLC-MSn, respectively. The relative contents of most ginsenosides were reduced in the extract of G-V. Furthermore, ginsenosides Rbt, Rb2, Rc and Rd could be metabolized to Rd, F2 and C-K in rat in- testinal bacteria. The metabolic speeds ofRbl, Rb2 and Re in the G-V extracts at ratios of 10 ： 5, 10 ： 7 and 10 ： 10 and the metabolic rates of ginsenosides Rbb Rb2 and Rc to Rd, Rd to F2 in all compatibility extracts were lower than that in the P ginseng extract. In conclusion, this study illustrated the mechanism of effect-reducing by comparison of the relative contents and metabolic profiles of ginsenosides after compatibility of P ginseng and V. nigrum L.展开更多
Magnetic nanoparticles(MNPs) are widely used for the immobilization of enzyme owing to the unique properties such as good biocompatibility and rapid separation. Herein, we used Fe_3O_4 magnetic nanoparticles(Fe_3O_4 M...Magnetic nanoparticles(MNPs) are widely used for the immobilization of enzyme owing to the unique properties such as good biocompatibility and rapid separation. Herein, we used Fe_3O_4 magnetic nanoparticles(Fe_3O_4 MNPs) as the carrier core with(3-aminopropyl)triethoxysilane(APTES)modification by our approach, in which a-glucosidase was stereoscopically immobilized on the surface of Fe_3O_4 MNPs via covalent binding. The result of immobilization was characterized by scanning electron microscope(SEM) and fourier transform-infrared spectroscopy(FT-IR). Then we optimized some key parameters of the immobilization reaction, including the ratio of MNPs to enzyme, GA concentration,crosslinking time and immobilization time. Moreover, under the optimal conditions, pH tolerance,thermo stability and reusability of the immobilized enzyme were investigated and compared with the free one. In order to evaluate the change of the affinity of the enzyme to its specific substrate after immobilization, the Michaelis-Menten constant(K_m) was also studied. Finally, the immobilized α-glucosidase combining with high performance liquid chromatography-tandem mass spectrometry technique(HPLC-MS/MS) was applied to screen and identify eight inhibitors from Polygonum cuspidatum extract. These results indicated that the established method had the broad prospects for biotechnological applications.展开更多
Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging.This study presented a one-pot synthesis of magnetic polydopamine nanoparticles(Fe3O4@-SiO2@PDA NPs)with multip...Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging.This study presented a one-pot synthesis of magnetic polydopamine nanoparticles(Fe3O4@-SiO2@PDA NPs)with multiple recognition sites for the magnetic dispersive solid-phase extraction(MDSPE)of ginsenosides from rat plasma treated with white ginseng.The extracted ginsenosides were characterized by combining an ultra-high-performance liquid chromatography coupled to a highresolution mass spectrometry with supplemental UNIFI libraries.Response surface methodology was statistically used to optimize the extraction procedure of the ginsenosides.The reusability of Fe3O4@-SiO2@PDA NPs was also examined and the results showed that the recovery rate exceeded 80%after recycling 6 times.Furthermore,the proposed method showed greater enrichment efficiency and could rapidly determine and characterize 23 ginsenoside prototypes and metabolites from plasma.In comparison,conventional methanol method can only detect 8 ginsenosides from the same plasma samples.The proposed approach can provide methodological reference for the trace determination and characterization of different bioactive ingredients and metabolites of traditional Chinese medicines and food.展开更多
In this work,the gas-Cherenkov detector with an off-axis parabolic reflector(Opr GCD)is designed using the Geant4 Monte Carlo simulation toolkit,which is helpful to improve the collection efficiency of Cherenkov photo...In this work,the gas-Cherenkov detector with an off-axis parabolic reflector(Opr GCD)is designed using the Geant4 Monte Carlo simulation toolkit,which is helpful to improve the collection efficiency of Cherenkov photons.The method to study the performance of Opr GCD based on femtosecond laser-wakefield-accelerated electron beams is presented.Cherenkov signals with high signal-to-noise ratio were obtained,and the measured Cherenkov signals changing with the CO2 pressure were consistent well with the simulation results.The design and study of this Opr GCD system lay the foundation for the application of fusion gamma diagnostics system in large laser facilities of China.展开更多
In order to study the damage of ambient fine particulate matter(PM2.5) to organism in the environment,the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabo...In order to study the damage of ambient fine particulate matter(PM2.5) to organism in the environment,the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabolic pathways to clarify the toxicity mechanisms. Particles of PM2.5 collected from the fibrous membrane were extracted ultrasonically and dissolved in physiological saline to prepare PM2.5 suspension. The solution of saline and fine particular matter was injected into the trachea of rats respectively. The rats were injected two times a week for four weeks. Samples of 24-h urine were collected at the 14 th day after the end of exposure, and the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used for the metabolomics detection. Principal component analysis(PCA) was used to investigate the global metabolomic alterations and a clear separation in the scatter diagram were observed. 17 potential endogenous metablites were identified from urinary samples in rats by UPLC-Q-TOF-MS. The primary metabolism pathways involved pentose and glucuronate interconversions, starch and sucrose metabolism, tryptophan metabolism, tyrosine metabolism, phenylalanine metabolism, purine metabolism, acetaminophen metabolism pathway, retinol metabolism and valproic acid metabolism pathway.The results are helpful to understand the toxicological mechanisms of PM2.5 and screened out potential biomarkers of rats which exposure to PM2.5.展开更多
Low density and low convergence implosion occurs in the exploding-pusher target experiment, and generates neutrons isotropically to develop a high yield platform.In order to validate the performance of ShenGuang(SG) l...Low density and low convergence implosion occurs in the exploding-pusher target experiment, and generates neutrons isotropically to develop a high yield platform.In order to validate the performance of ShenGuang(SG) laser facility and test nuclear diagnostics, all 48-beam lasers with an on-target energy of 48 kJ were firstly used to drive room-temperature, DT gas-filled glass targets.The optimization has been carried out and optimal drive uniformity was obtained by the combination of beam repointing and target.The final irradiation uniformity of less than 5% on polar direct-drive capsules of 540 μm in diameter was achieved, and the highest thermonuclear yield of the polar direct-drive DT fuel implosion at the SG was 1.04 × 10^(13).The experiment results show neutron yields severely depend on the irradiation uniformity and laser timing,and decrease with the increase of the diameter and fuel pressure of the target.The thin CH ablator does not impact the implosion performance, but the laser drive uniformity is important.The simulated results validate that the cos γ distribution laser design is reasonable and can achieve a symmetric pressure distribution.Further optimization will focus on measuring the symmetry of the hot spot by self-emission imaging, increasing the diameter, and decreasing the fuel pressure.展开更多
基金The CAS Strategic Pilot Science and Technology of China under contract Nos XDA11020205 and XDA05030403the National Project of Basic Sciences and Technology of China under contract Nos 2012FY112400 and 2013FY111200+1 种基金the National Natural Science Foundation of China under contract Nos 41276162,41130855,41276161 and 40906057the Natural Science Foundation of Guangdong Province of China under contract No.S2011040000151
文摘Mesoscale eddies have been suggested to have an impact on biological carbon fixation in the South China Sea （SCS）. However, their overall contribution to primary production during the spring inter-monsoon pe riod is still unknown. Based on large-scale biological and environmental in situ observations and synchro nous remote sensing data, the distribution patterns of phytoplankton biomass and the primary production, and the role of mesoscale eddies in regulating primary production in different eddy-controlled waters were investigated. The results suggested that the surface chlorophyll a concentrations and water column inte grated primary production （IPP） are significantly higher in cyclonic eddies and lower in the anticyclonic eddies as compared to that in non-eddy waters. Although eddies could affect various environmental factors, such as nutrients, temperature and light availability, nutrient supply is suggested to be the most important one through which mesoscale eddies regulated the distribution patterns of phytoplankton biomass and pri mary production. The estimated IPP in cyclonic and anticyclonic eddies are about 29.5% higher and 16.6% lower than the total average in the whole study area, respectively, indicating that the promotion effect of mesoscale cold eddies on the primary production was much stronger than the inhibition effect of the warm eddies per unit area. Overall, mesoscale eddies are crucial physical processes that affect the biological car bon fixation and the distribution pattern of primary production in the SCS open sea, especially during the spring inter-monsoon period.
基金supported by the Youth Project of the National Natural Science Foundation of China(Grant No.62201237)the Yunnan Fundamental Research Projects(Grant Nos.202101BE070001-008 and202301AV070003)+1 种基金the Youth Project of the Xingdian Talent Support Plan of Yunnan Province(Grant No.KKRD202203068)the Major Science and Technology Projects in Yunnan Province(Grant No.202202AD080013)。
文摘The multitude of airborne point clouds limits the point cloud processing efficiency.Superpoints are grouped based on similar points,which can effectively alleviate the demand for computing resources and improve processing efficiency.However,existing superpoint segmentation methods focus only on local geometric structures,resulting in inconsistent spectral features of points within a superpoint.Such feature inconsistencies degrade the performance of subsequent tasks.Thus,this study proposes a novel Superpoint Segmentation method that jointly utilizes spatial Geometric and Spectral Information for multispectral point cloud superpoint segmentation(GSI-SS).Specifically,a similarity metric that combines spatial geometry and spectral information is proposed to facilitate the consistency of geometric structures and object attributes within segmented superpoints.Following the formation of the primary superpoints,an intersuperpoint pointexchange mechanism that maximizes feature consistency within the final superpoints is proposed.Experiments are conducted on two real multispectral point cloud datasets,and the proposed method achieved higher recall,precision,F score,and lower global consistency and feature classification errors.The experimental results demonstrate the superiority of the proposed GSI-SS over several state-of-the-art methods.
文摘In traditional Chinese medicine theory, Panax ginseng and Veratrum nigrum L. is an important incompatible herb pair. Studies on the content variation of main components and the influences on the metabolism in rat intestinal bacteria are useful to understand the mechanism of incompatibility of this herb pairs. In this study, the content variation of ginsenosides and their metaboltic profiles in the extracts of P. ginseng and compatibility of P. ginseng with V. nigrum L. （G-V） were investigated using relative quantitative method of electrospray ionization mass spec- trometry （ESI-MS） and UPLC-MSn, respectively. The relative contents of most ginsenosides were reduced in the extract of G-V. Furthermore, ginsenosides Rbt, Rb2, Rc and Rd could be metabolized to Rd, F2 and C-K in rat in- testinal bacteria. The metabolic speeds ofRbl, Rb2 and Re in the G-V extracts at ratios of 10 ： 5, 10 ： 7 and 10 ： 10 and the metabolic rates of ginsenosides Rbb Rb2 and Rc to Rd, Rd to F2 in all compatibility extracts were lower than that in the P ginseng extract. In conclusion, this study illustrated the mechanism of effect-reducing by comparison of the relative contents and metabolic profiles of ginsenosides after compatibility of P ginseng and V. nigrum L.
基金funded by the National Natural Science Foundation of China(Nos.81473537,81773690,21673219)
文摘Magnetic nanoparticles(MNPs) are widely used for the immobilization of enzyme owing to the unique properties such as good biocompatibility and rapid separation. Herein, we used Fe_3O_4 magnetic nanoparticles(Fe_3O_4 MNPs) as the carrier core with(3-aminopropyl)triethoxysilane(APTES)modification by our approach, in which a-glucosidase was stereoscopically immobilized on the surface of Fe_3O_4 MNPs via covalent binding. The result of immobilization was characterized by scanning electron microscope(SEM) and fourier transform-infrared spectroscopy(FT-IR). Then we optimized some key parameters of the immobilization reaction, including the ratio of MNPs to enzyme, GA concentration,crosslinking time and immobilization time. Moreover, under the optimal conditions, pH tolerance,thermo stability and reusability of the immobilized enzyme were investigated and compared with the free one. In order to evaluate the change of the affinity of the enzyme to its specific substrate after immobilization, the Michaelis-Menten constant(K_m) was also studied. Finally, the immobilized α-glucosidase combining with high performance liquid chromatography-tandem mass spectrometry technique(HPLC-MS/MS) was applied to screen and identify eight inhibitors from Polygonum cuspidatum extract. These results indicated that the established method had the broad prospects for biotechnological applications.
基金This work was supported by grants from the National Natural Science Foundation of China Key Program(NO.81530094)General Program(NO.81573574,81873193)the Science and Technology Development Project of Jilin Province(20190201283JC).
文摘Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging.This study presented a one-pot synthesis of magnetic polydopamine nanoparticles(Fe3O4@-SiO2@PDA NPs)with multiple recognition sites for the magnetic dispersive solid-phase extraction(MDSPE)of ginsenosides from rat plasma treated with white ginseng.The extracted ginsenosides were characterized by combining an ultra-high-performance liquid chromatography coupled to a highresolution mass spectrometry with supplemental UNIFI libraries.Response surface methodology was statistically used to optimize the extraction procedure of the ginsenosides.The reusability of Fe3O4@-SiO2@PDA NPs was also examined and the results showed that the recovery rate exceeded 80%after recycling 6 times.Furthermore,the proposed method showed greater enrichment efficiency and could rapidly determine and characterize 23 ginsenoside prototypes and metabolites from plasma.In comparison,conventional methanol method can only detect 8 ginsenosides from the same plasma samples.The proposed approach can provide methodological reference for the trace determination and characterization of different bioactive ingredients and metabolites of traditional Chinese medicines and food.
文摘In this work,the gas-Cherenkov detector with an off-axis parabolic reflector(Opr GCD)is designed using the Geant4 Monte Carlo simulation toolkit,which is helpful to improve the collection efficiency of Cherenkov photons.The method to study the performance of Opr GCD based on femtosecond laser-wakefield-accelerated electron beams is presented.Cherenkov signals with high signal-to-noise ratio were obtained,and the measured Cherenkov signals changing with the CO2 pressure were consistent well with the simulation results.The design and study of this Opr GCD system lay the foundation for the application of fusion gamma diagnostics system in large laser facilities of China.
基金supported by the National Natural Science Foundation of China (No. 31400453)
文摘In order to study the damage of ambient fine particulate matter(PM2.5) to organism in the environment,the method of urinary metabolomics was used to detect the potential endogenous metabolites and their related metabolic pathways to clarify the toxicity mechanisms. Particles of PM2.5 collected from the fibrous membrane were extracted ultrasonically and dissolved in physiological saline to prepare PM2.5 suspension. The solution of saline and fine particular matter was injected into the trachea of rats respectively. The rats were injected two times a week for four weeks. Samples of 24-h urine were collected at the 14 th day after the end of exposure, and the ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used for the metabolomics detection. Principal component analysis(PCA) was used to investigate the global metabolomic alterations and a clear separation in the scatter diagram were observed. 17 potential endogenous metablites were identified from urinary samples in rats by UPLC-Q-TOF-MS. The primary metabolism pathways involved pentose and glucuronate interconversions, starch and sucrose metabolism, tryptophan metabolism, tyrosine metabolism, phenylalanine metabolism, purine metabolism, acetaminophen metabolism pathway, retinol metabolism and valproic acid metabolism pathway.The results are helpful to understand the toxicological mechanisms of PM2.5 and screened out potential biomarkers of rats which exposure to PM2.5.
基金Project supported by the National Natural Science Foundation of China(Grant No.11605178)the Science Challenging Project,China(Grant Nos.JCKY2016212A505 and TZ2016001)
文摘Low density and low convergence implosion occurs in the exploding-pusher target experiment, and generates neutrons isotropically to develop a high yield platform.In order to validate the performance of ShenGuang(SG) laser facility and test nuclear diagnostics, all 48-beam lasers with an on-target energy of 48 kJ were firstly used to drive room-temperature, DT gas-filled glass targets.The optimization has been carried out and optimal drive uniformity was obtained by the combination of beam repointing and target.The final irradiation uniformity of less than 5% on polar direct-drive capsules of 540 μm in diameter was achieved, and the highest thermonuclear yield of the polar direct-drive DT fuel implosion at the SG was 1.04 × 10^(13).The experiment results show neutron yields severely depend on the irradiation uniformity and laser timing,and decrease with the increase of the diameter and fuel pressure of the target.The thin CH ablator does not impact the implosion performance, but the laser drive uniformity is important.The simulated results validate that the cos γ distribution laser design is reasonable and can achieve a symmetric pressure distribution.Further optimization will focus on measuring the symmetry of the hot spot by self-emission imaging, increasing the diameter, and decreasing the fuel pressure.
