A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints ...A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints from Xinjiang Province in northwestern China. More than 150 tridactyl theropod dinosaur footprints are preserved as positive hyporeliefs on the lower bedding plane of a fine-grained sandstone body. Most of the footprints are isolated and appear to be randomly distributed. Some show well defined phalangeal pads, heels and rarely indistinct impressions of the distal part of the metatarsus. Two distinct morphotypes are present: a larger type with relatively broad pads shows similarities to Changpeipus and Megalosauripus, and a slightly smaller, slender and gracile type which is similar to Grallator, Eubrontes and Anchisauripus. In both morphotypes, digit III is the longest with a length between 11.4 and 33.6 cm. A single imprint shows prominent scratches, probably formed during slipping of the track maker.展开更多
Bridge deformation monitoring usually adopts contact sensors,and the implementation process is often limited by the environment and observation conditions,resulting in unsatisfactory monitoring accuracy and effect.Gro...Bridge deformation monitoring usually adopts contact sensors,and the implementation process is often limited by the environment and observation conditions,resulting in unsatisfactory monitoring accuracy and effect.Ground-Based Synthetic Aperture Radar(GBSAR)combined with corner reflectors was used to perform static load-loaded deformation destruction experiments on solid model bridges in a non-contact manner.The semi parametric spline filtering and its optimization method were used to obtain the monitoring results of the GBSAR radar’s line of sight deformation,and the relative position of the corner reflector and the millimeter level deformation signals under different loading conditions were successfully extracted.The deformation transformation model from the radar line of sight direction to the vertical vibration direction was deduced.The transformation results of deformation monitoring and the measurement data such as the dial indicator were compared and analyzed.The occurrence and development process of bridge deformation and failure were successfully monitored,and the deformation characteristics of the bridge from continuous loading to eccentric loading until bridge failure were obtained.The experimental results show that GBSAR combined with corner reflector can be used for deformation feature acquisition,damage identification and health monitoring of bridges and other structures,and can provide a useful reference for design,construction and safety evaluation.展开更多
Neural interfaces based on surface Electromyography(EMG)decomposition have been widely used in upper limb prosthetic systems.In the current EMG decomposition framework,most Blind Source Separation(BSS)algorithms requi...Neural interfaces based on surface Electromyography(EMG)decomposition have been widely used in upper limb prosthetic systems.In the current EMG decomposition framework,most Blind Source Separation(BSS)algorithms require EMG with a large number of channels(generally larger than 64)as input,while users of prosthetic limbs can generally only provide less skin surface for electrode placement than healthy people.We performed decomposition tests to demonstrate the performance of the new framework with the simulated EMG signal.The results show that the new framework identified more Motor Units(MUs)compared to the control group and it is suitable for decomposing EMG signals with low channel numbers.In order to verify the application value of the new framework in the upper limb prosthesis system,we tested its performance in decomposing experimental EMG signals in force fitting experiments as well as pattern recognition experiments.The average Pearson coefficient between the fitted finger forces and the ground truth forces is 0.9079 and the average accuracy of gesture classification is 95.11%.The results show that the decomposition results obtained by the new framework can be used in the control of the upper limb prosthesis while only requiring EMG signals with fewer channels.展开更多
An aquatic fern leaf,Flabellariopteris mii Sun gen.et sp.nov.from the Late Triassic of Western Liaoning,China,is described and proposed as the type species of the new morphortaxon of the Marsileaceae.The fossil leaves...An aquatic fern leaf,Flabellariopteris mii Sun gen.et sp.nov.from the Late Triassic of Western Liaoning,China,is described and proposed as the type species of the new morphortaxon of the Marsileaceae.The fossil leaves are preserved as impression.No fertile and rhizomatic materials are found.The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement.The petiole is slender.The leaflet is fan-shaped or semi-circular,and commonly divided into four wedge-shaped lobes.Terminal margin of lobes is usually incised,incisions shallow or deep,with bluntly rounded or notched apex.The veins are conspicuously dichotomous,but anastomoses and marginal vein are absent.The unique morphological features,including twoparted thin leaflets,size,shape,veins and slender petiole,indicate that the present specimen represents an aquatic fern,which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras.展开更多
Diffuse intrinsic pontine glioma(DIPG) is the main cause of brain tumor-related death among children.Until now, there is still a lack of effective therapy with prolonged overall survival for this disease. A typical st...Diffuse intrinsic pontine glioma(DIPG) is the main cause of brain tumor-related death among children.Until now, there is still a lack of effective therapy with prolonged overall survival for this disease. A typical strategy for preclinical cancer research is to find out the molecular differences between tumor tissue and para-tumor normal tissue, in order to identify potential therapeutic targets. Unfortunately, it is impossible to obtain normal tissue for DIPG because of the vital functions of the pons.Here we report the human fetal hindbrain-derived neural progenitor cells(pontine progenitor cells, PPCs) as normal control cells for DIPG. The PPCs not only harbored similar cell biological and molecular signatures as DIPG glioma stem cells, but also had the potential to be immortalized by the DIPG-specific mutation H3 K27 M in vitro. These findings provide researchers with a candidate normal control and a potential medicine carrier for preclinical research on DIPG.展开更多
The nonlinear sorption of hydrophobic organic contaminants(HOCs)could be changed to linear sorption by the suppression of coexisting solutes in natural system,resulting in the enhancement of mobility,bioavailability a...The nonlinear sorption of hydrophobic organic contaminants(HOCs)could be changed to linear sorption by the suppression of coexisting solutes in natural system,resulting in the enhancement of mobility,bioavailability and risks of HOCs in the environment.In previous study,inspired from the competitive adsorption on activated carbon(AC),the displaceable fraction of HOCs sorption to soot by competitor was attributed to the adsorption on elemental carbon fraction of soot(EC-Soot),while the linear and nondisplaceable fraction was attributed to the partition in authigenic organic matter of soot(OM-Soot).In this study,however,we observed that the linear and nondisplaceable fraction of HOC(naphthalene)to a diesel soot(D-Soot)by competitor(phenanthrene or p-nitrophenol)should be attributed to not only the linear partition in OM-Soot,but also the residual linear adsorption on EC-Soot.We also observed that the competition on the surface of soot dominated by external surface was different from that of AC dominated by micropore surface,i.e.,complete displacement of HOCs by p-nitrophenol could occur for the micropore surface of AC,but not for the external surface of soot.These observations were obtained through the separation of EC-Soot and OM-Soot from D-Soot with organic-solvent extraction and the sorption comparisons of D-Soot with an AC(ACF300)and a multiwalled carbon nanotube(MWCNT30).The obtained results would give new insights to the sorption mechanisms of HOCs by soot and help to assess their environmental risks.展开更多
Nonradical oxidation based on peroxydisulfate(PDS)activation has attracted increasing attention for selective degradation of organic pollutants.Herein,topological defects were introduced into biochar(BC)via removing N...Nonradical oxidation based on peroxydisulfate(PDS)activation has attracted increasing attention for selective degradation of organic pollutants.Herein,topological defects were introduced into biochar(BC)via removing N atoms in N-doped BC(NBC)in an attempt to improve the nonradical catalytic performance.Compared to the pristine BC and NBC,the introduction of topological defects could achieve up to 36.6-and 8.7-times catalytic activity enhancement,respectively.More importantly,it was found that the catalytic activity was dominated by topological defects,which was verified by the significant positive correlation between the pseudo-first-order rate constants and the content of topological defects.Theoretical calculations suggested that topological defects enhanced the electrondonating ability of BC by reducing the energy gap,which made the electrons transfer to PDS molecules more easily.As a result,holes were generated after the carbon defects lost electrons,and induced a nonradical oxidation process.Benefiting from the merits of nonradical oxidation,the developed BC/PDS system showed superior performance in removing electron-rich contaminants in the presence of inorganic anions and in the actual environments.This study not only provides a potential avenue for designing efficient biochar-based catalysts,but also advances the mechanism understanding of nonradical oxidation process induced by carbon defects.展开更多
文摘A new dinosaur tracksite was discovered in a steeply inclined sandstone layer of the Middle Jurassic Sanjianfang Formation in the Shanshan area of the Turpan Basin. The site is the first record of dinosaur footprints from Xinjiang Province in northwestern China. More than 150 tridactyl theropod dinosaur footprints are preserved as positive hyporeliefs on the lower bedding plane of a fine-grained sandstone body. Most of the footprints are isolated and appear to be randomly distributed. Some show well defined phalangeal pads, heels and rarely indistinct impressions of the distal part of the metatarsus. Two distinct morphotypes are present: a larger type with relatively broad pads shows similarities to Changpeipus and Megalosauripus, and a slightly smaller, slender and gracile type which is similar to Grallator, Eubrontes and Anchisauripus. In both morphotypes, digit III is the longest with a length between 11.4 and 33.6 cm. A single imprint shows prominent scratches, probably formed during slipping of the track maker.
基金Science and Technology Innovation Program of Hunan Province(No.2021RC4037)National Natural Science Foundation of China:Deformation Monitoring Key Technology and Damage Mechanism Research on Data Fusion among GB-SAR and Multi-sensors(No.41877283)Scientific Research Project of Hunan Provincial Department of Natural Resources(No.2021-18)
文摘Bridge deformation monitoring usually adopts contact sensors,and the implementation process is often limited by the environment and observation conditions,resulting in unsatisfactory monitoring accuracy and effect.Ground-Based Synthetic Aperture Radar(GBSAR)combined with corner reflectors was used to perform static load-loaded deformation destruction experiments on solid model bridges in a non-contact manner.The semi parametric spline filtering and its optimization method were used to obtain the monitoring results of the GBSAR radar’s line of sight deformation,and the relative position of the corner reflector and the millimeter level deformation signals under different loading conditions were successfully extracted.The deformation transformation model from the radar line of sight direction to the vertical vibration direction was deduced.The transformation results of deformation monitoring and the measurement data such as the dial indicator were compared and analyzed.The occurrence and development process of bridge deformation and failure were successfully monitored,and the deformation characteristics of the bridge from continuous loading to eccentric loading until bridge failure were obtained.The experimental results show that GBSAR combined with corner reflector can be used for deformation feature acquisition,damage identification and health monitoring of bridges and other structures,and can provide a useful reference for design,construction and safety evaluation.
基金This study was funded by the National Natural Science Foundation of China(Grant NO.91948302,U1813209,NO.51875120).
文摘Neural interfaces based on surface Electromyography(EMG)decomposition have been widely used in upper limb prosthetic systems.In the current EMG decomposition framework,most Blind Source Separation(BSS)algorithms require EMG with a large number of channels(generally larger than 64)as input,while users of prosthetic limbs can generally only provide less skin surface for electrode placement than healthy people.We performed decomposition tests to demonstrate the performance of the new framework with the simulated EMG signal.The results show that the new framework identified more Motor Units(MUs)compared to the control group and it is suitable for decomposing EMG signals with low channel numbers.In order to verify the application value of the new framework in the upper limb prosthesis system,we tested its performance in decomposing experimental EMG signals in force fitting experiments as well as pattern recognition experiments.The average Pearson coefficient between the fitted finger forces and the ground truth forces is 0.9079 and the average accuracy of gesture classification is 95.11%.The results show that the decomposition results obtained by the new framework can be used in the control of the upper limb prosthesis while only requiring EMG signals with fewer channels.
基金supported by China Geological Survey Grant(1212011120149)the National Natural Science Foundation of China (41172009)+1 种基金Doctoral Fund of Ministry of Education of China (2010006110034)the National Project of China’Higher Education and Program for Introducing Talents of Discipline of Universities of China (Jilin University)
文摘An aquatic fern leaf,Flabellariopteris mii Sun gen.et sp.nov.from the Late Triassic of Western Liaoning,China,is described and proposed as the type species of the new morphortaxon of the Marsileaceae.The fossil leaves are preserved as impression.No fertile and rhizomatic materials are found.The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement.The petiole is slender.The leaflet is fan-shaped or semi-circular,and commonly divided into four wedge-shaped lobes.Terminal margin of lobes is usually incised,incisions shallow or deep,with bluntly rounded or notched apex.The veins are conspicuously dichotomous,but anastomoses and marginal vein are absent.The unique morphological features,including twoparted thin leaflets,size,shape,veins and slender petiole,indicate that the present specimen represents an aquatic fern,which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras.
基金supported by Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (ZYLX201608)the Beijing Municipal Natural Science Foundation (7161004)
文摘Diffuse intrinsic pontine glioma(DIPG) is the main cause of brain tumor-related death among children.Until now, there is still a lack of effective therapy with prolonged overall survival for this disease. A typical strategy for preclinical cancer research is to find out the molecular differences between tumor tissue and para-tumor normal tissue, in order to identify potential therapeutic targets. Unfortunately, it is impossible to obtain normal tissue for DIPG because of the vital functions of the pons.Here we report the human fetal hindbrain-derived neural progenitor cells(pontine progenitor cells, PPCs) as normal control cells for DIPG. The PPCs not only harbored similar cell biological and molecular signatures as DIPG glioma stem cells, but also had the potential to be immortalized by the DIPG-specific mutation H3 K27 M in vitro. These findings provide researchers with a candidate normal control and a potential medicine carrier for preclinical research on DIPG.
基金supported partly by the National Natural Science Foundation of China(Nos.21777138 and 21621005)the National Key Research and Development Program of China(No.2017YFA0207001)+1 种基金the Key Research and Development Program of Zhejiang Province(No.2019C03105)。
文摘The nonlinear sorption of hydrophobic organic contaminants(HOCs)could be changed to linear sorption by the suppression of coexisting solutes in natural system,resulting in the enhancement of mobility,bioavailability and risks of HOCs in the environment.In previous study,inspired from the competitive adsorption on activated carbon(AC),the displaceable fraction of HOCs sorption to soot by competitor was attributed to the adsorption on elemental carbon fraction of soot(EC-Soot),while the linear and nondisplaceable fraction was attributed to the partition in authigenic organic matter of soot(OM-Soot).In this study,however,we observed that the linear and nondisplaceable fraction of HOC(naphthalene)to a diesel soot(D-Soot)by competitor(phenanthrene or p-nitrophenol)should be attributed to not only the linear partition in OM-Soot,but also the residual linear adsorption on EC-Soot.We also observed that the competition on the surface of soot dominated by external surface was different from that of AC dominated by micropore surface,i.e.,complete displacement of HOCs by p-nitrophenol could occur for the micropore surface of AC,but not for the external surface of soot.These observations were obtained through the separation of EC-Soot and OM-Soot from D-Soot with organic-solvent extraction and the sorption comparisons of D-Soot with an AC(ACF300)and a multiwalled carbon nanotube(MWCNT30).The obtained results would give new insights to the sorption mechanisms of HOCs by soot and help to assess their environmental risks.
基金National Key Research and Development Program of China(2021YFC1809204)National Natural Science Foundation of China(42192573,21621005,and U21A20163)+1 种基金Research and Development Program of Zhejiang Province,China(2021C0167)Fundamental Research Funds for the Central Universities(226-2022-00212).
文摘Nonradical oxidation based on peroxydisulfate(PDS)activation has attracted increasing attention for selective degradation of organic pollutants.Herein,topological defects were introduced into biochar(BC)via removing N atoms in N-doped BC(NBC)in an attempt to improve the nonradical catalytic performance.Compared to the pristine BC and NBC,the introduction of topological defects could achieve up to 36.6-and 8.7-times catalytic activity enhancement,respectively.More importantly,it was found that the catalytic activity was dominated by topological defects,which was verified by the significant positive correlation between the pseudo-first-order rate constants and the content of topological defects.Theoretical calculations suggested that topological defects enhanced the electrondonating ability of BC by reducing the energy gap,which made the electrons transfer to PDS molecules more easily.As a result,holes were generated after the carbon defects lost electrons,and induced a nonradical oxidation process.Benefiting from the merits of nonradical oxidation,the developed BC/PDS system showed superior performance in removing electron-rich contaminants in the presence of inorganic anions and in the actual environments.This study not only provides a potential avenue for designing efficient biochar-based catalysts,but also advances the mechanism understanding of nonradical oxidation process induced by carbon defects.
