Leaf trait networks(LTNs)visualize the intricate linkages reflecting plant trait-functional coordination.Typical karst vegetation,developed from lithological dolomite and limestone,generally exhibits differential comm...Leaf trait networks(LTNs)visualize the intricate linkages reflecting plant trait-functional coordination.Typical karst vegetation,developed from lithological dolomite and limestone,generally exhibits differential communities,possibly due to habitat rock exposure,soil depth,and soil physicochemical properties variations,leading to a shift from plant trait variation to functional linkages.However,how soil and habitat quality affect the differentiation of leaf trait networks remains unclear.LTNs were constructed for typical dolomite and limestone habitats by analyzing twenty-one woody plant leaf traits across fifty-six forest subplots in karst mountains.The differences between dolomite and limestone LTNs were compared using network parameters.The network association of soil and habitat quality was analyzed using redundancy analysis(RDA),Mantle's test,and a random forest model.The limestone LTN exhibited significantly higher edge density with lower diameter and average path length when compared to the dolomite LTN.It indicates LTN differentiation,with the limestone network displaying a more compact architecture and higher connectivity than the dolomite network.The specific leaf phosphorus and leaf nitrogen contents of dolomite LTN,as well as the leaf mass and leaf carbon contents of limestone LTN,significantly contributed to network degree and closeness,serving as crucial node traits regulating LTN connectedness.Additionally,both habitat LTNs significantly correlated with soil nitrogen and phosphorus,stoichiometric ratios,pH,and organic carbon,as well as soil depth and rock exposure rates,with soil depth and rock exposure showing greater relative importance.Soil depth and rock exposure dominate trait network differentiation,with the limestone habitat exhibiting a more compact network architecture than the dolomite habitat.展开更多
Wearable triboelectric nanogenerators(TENGs)have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance.Herein,polyetherimide-Al_(2)O_(3)(PAl)and polyvinylide...Wearable triboelectric nanogenerators(TENGs)have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance.Herein,polyetherimide-Al_(2)O_(3)(PAl)and polyvinylidene fluoride-co-hexafluoropropylene(PVDF-HFP,PH)nanofiber membranes were used as tribo-positive and tribo-negative materials,respectively.Phytic acid-doped polyaniline(PANI)/cotton fabric(PPCF)and ethylenediamine(EDA)-crosslinked PAl(EPAl)nanofiber membranes were used as triboelectrode and triboencapsulation materials,respectively.The result showed that when the PAl-PH-based TENG was shaped as a circle with a radius of 1 cm,under the pressure of 50 N,and the frequency of 0.5 Hz,the open-circuit voltage(V_(oc))and short-circuit current(I_(sc))reached the highest value of 66.6 V and-93.4 to 110.1 nA,respectively.Moreover,the PH-based TENG could be used as a fabric sensor to detect fabric composition and as a sensor-inductive switch for light bulbs or beeping warning devices.When the PAl-PH-based TENG was shaped as a 5×5 cm^(2)rectangle,a 33 pF capacitor could be charged to 15 V in 28 s.Interestingly,compared to PAl nanofiber membranes,EPAl nanofiber membranes exhibited good dyeing properties and excellent solvent resistance.The PPCF exhibited<5%resistance change after washing,bending,and stretching.展开更多
Previous studies recognized three major lineages of the family Costaceae:a South American clade,an Asian clade and a Costus clade.However,the genus Hellenia within the Asian clade has been shown to be non-monophyletic...Previous studies recognized three major lineages of the family Costaceae:a South American clade,an Asian clade and a Costus clade.However,the genus Hellenia within the Asian clade has been shown to be non-monophyletic and its morphology has not been studied carefully.Therefore,the complete plastid genomes of Hellenia species were obtained and the monophyly of Hellenia was tested through four different datasets in this study.Plastid phylogenomic analyses of Costaceae revealed that Hellenia is strongly supported as paraphyletic.Two major clades are recovered,namely the Hellenia s.s.subclade and the Parahellenia subclade.Phylogenetic analyses based on an enlarged taxon sampling of the Asian clade using a two chloroplast markers dataset(trnK intron and trnL-F spacer)confirmed the paraphyly of Hellenia.Meanwhile,morphological analyses suggested that members of the Parahellenia subclade differ from the remaining Hellenia species in many characters including inflorescences,bracts,stigma,axillary buds,floral tubes and labellum.According to the present molecular and morphological evidence,the latter subclade is recognized as a new genus,Parahellenia.Two new species are described,four new combinations are made,and identification keys are also provided.展开更多
Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable d...Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable dendrite growth and serious oxygen corrosion issue on Li surface. Herein, a sulfur-modified Li surface can be successfully constructed via chemical reaction of guanylthiourea(GTU) molecule on Li,which can induce the selectively fast decomposition of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI) to form a smooth and stable inorganics-rich solid-electrolyte interphase(IR-SEI) during the subsequent electrochemical process. Such an IR-SEI cannot only offer a highly reversible and stable Li plating/stripping chemistry with dendrite-free property(10 mA cm^(-2)-10 mAh cm^(-2), > 0.5 years;3 mA cm^(-2)-3 m Ah cm^(-2), > 1 year) but also endows the Li metal an anti-oxygen corrosion function, thereby significantly improving the cycling stability of Li-Obatteries. This work provides a new idea for constructing functional solid-electrolyte interphase(SEI) to achieve highly stable Li metal anode.展开更多
The spectroscopic methods for the ultrafast electronic and structural dynamics of materials require fully coherent extreme ultraviolet and soft X-ray radiation with high-average brightness.Seeded free-electron lasers(...The spectroscopic methods for the ultrafast electronic and structural dynamics of materials require fully coherent extreme ultraviolet and soft X-ray radiation with high-average brightness.Seeded free-electron lasers(FELs)are ideal sources for delivering fully coherent soft X-ray pulses.However,due to state-of-theart laser system limitations,it is challenging to meet the ultraviolet seed laser’s requirements of sufficient energy modulation and high repetition rates simultaneously.The self-modulation scheme has been proposed and recently demonstrated in a seeded FEL to relax the seed laser requirements.Using numerical simulations,we show that the required seed laser intensity in the self-modulation is~3 orders of magnitude lower than that in the standard high-gain harmonic generation(HGHG).The harmonic self-modulation can launch a singlestage HGHG FEL lasing at the 30th harmonic of the seed laser.Moreover,the proof-of-principle experimental results confirm that the harmonic self-modulation can still amplify the laser-induced energy modulation.These achievements reveal that the self-modulation can not only remarkably reduce the requirements of the seed laser but also improve the harmonic upconversion efficiency,which paves the way for realizing high-repetitionrate and fully coherent soft X-ray FELs.展开更多
X-ray beams carrying orbital angular momentum(OAM)are an emerging tool for probing matter.Optical elements,such as spiral phase plates and zone plates,have been widely used to generate OAM light.However,due to the hig...X-ray beams carrying orbital angular momentum(OAM)are an emerging tool for probing matter.Optical elements,such as spiral phase plates and zone plates,have been widely used to generate OAM light.However,due to the high impinging intensities,these optics are challenging to use at X-ray free-electron lasers(XFELs).Here,we propose a self-seeded free-electron laser(FEL)method to produce intense X-ray vortices.Unlike passive filtering after amplification,an optical element will be used to introduce the helical phase to the radiation pulse in the linear regime,significantly reducing thermal load on the optical element.The generated OAM pulse is then used as a seed and significantly amplified.Theoretical analysis and numerical simulations demonstrate that the power of the OAM seed pulse can be amplified by more than two orders of magnitude,reaching peak powers of several tens of gigawatts.The proposed method paves the way for high-power and high-repetition-rate OAM pulses of XFEL light.展开更多
ZBTB7A, a member of the POZ/BTB and Krüppel （POK） family of transcription factors, has been shown to have a context-dependent role in cancer development and progression. The role of ZBTB7A in estrogen receptor ...ZBTB7A, a member of the POZ/BTB and Krüppel （POK） family of transcription factors, has been shown to have a context-dependent role in cancer development and progression. The role of ZBTB7A in estrogen receptor alpha （ERα）-positive breast cancer is largely unknown. Approximately 70% of breast cancers are classified as ERα-positive. ERα carries out the biological effects of estrogen and its expression level dictates response to endocrine therapies and prognosis for breast cancer patients. In this study, we find that ZBTB7A transcriptionally regulates ERα expression in ERα-positive breast cancer cell lines by binding to the ESR1 promoter leading to increased transcription of ERα. Inhibition of ZBTB7A in ERα-positive cells results in decreased estrogen responsiveness as demonstrated by diminished estrogen-response element-driven luciferase reporter activity, induction of estrogen target genes, and estrogen-stimulated growth. We also report that ERα potentiates ZBTB7A expression via a post-translational mechanism, suggesting the presence of a positive feedback loop between ZBTB7A and ERα, conferring sensitivity to estrogen in breast cancer. Clinically, we find that ZBTB7A and ERα are often co-expressed in breast cancers and that high ZBTB7A expression correlates with improved overall and relapse-free survival for breast cancer patients. Importantly, high ZBTB7A expression predicts a more favorable outcome for patients treated with endocrine therapies. Together, these findings demonstrate that ZBTB7A contributes to the transcriptional program maintaining ERα expression and potentially an endocrine therapy-responsive phenotype in breast cancer.展开更多
As a new-generation light source,free-electron lasers(FELs)provide high-brightness x-ray pulses at the angstrom-femtosecond space and time scales.The fundamental physics behind the FEL is the interaction between an el...As a new-generation light source,free-electron lasers(FELs)provide high-brightness x-ray pulses at the angstrom-femtosecond space and time scales.The fundamental physics behind the FEL is the interaction between an electromagnetic wave and a relativistic electron beam in an undulator,which consists of hundreds or thousands of dipole magnets with an alternating magnetic field.We report the first observation of the laser–beam interaction in a pure dipole magnet in which the electron beam energy modulation with a 40-ke V amplitude and a 266-nm period is measured.We demonstrate that such an energy modulation can be used to launch a seeded FEL,that is,lasing at the sixth harmonic of the seed laser in a high-gain harmonic generation scheme.The results reveal the most basic process of the FEL lasing and open up a new direction for the study and exploitation of laser–beam interactions.展开更多
Accurate wheat spike detection is crucial in wheat field phenotyping for precision farming.Advances in artificial intelligence have enabled deep learning models to improve the accuracy of detecting wheat spikes.Howeve...Accurate wheat spike detection is crucial in wheat field phenotyping for precision farming.Advances in artificial intelligence have enabled deep learning models to improve the accuracy of detecting wheat spikes.However,wheat growth is a dynamic process characterized by important changes in the color feature of wheat spikes and the background.Existing models for wheat spike detection are typically designed for a specific growth stage.Their adaptability to other growth stages or field scenes is limited.Such models cannot detect wheat spikes accurately caused by the difference in color,size,and morphological features between growth stages.This paper proposes WheatNet to detect small and oriented wheat spikes from the filling to the maturity stage.WheatNet constructs a Transform Network to reduce the effect of differences in the color features of spikes at the filling and maturity stages on detection accuracy.Moreover,a Detection Network is designed to improve wheat spike detection capability.A Circle Smooth Label is proposed to classify wheat spike angles in drone imagery.A new micro-scale detection layer is added to the network to extract the features of small spikes.Localization loss is improved by Complete Intersection over Union to reduce the impact of the background.The results show that WheatNet can achieve greater accuracy than classical detection methods.The detection accuracy with average precision of spike detection at the filling stage is 90.1%,while it is 88.6%at the maturity stage.It suggests that WheatNet is a promising tool for detection of wheat spikes.展开更多
Bearings are key components of cone bit,thus its rapid failure is a major cause of leading to lower life of the bit.To improve the bearing performance and prolong working life,contact mechanics of hollow cylindrical r...Bearings are key components of cone bit,thus its rapid failure is a major cause of leading to lower life of the bit.To improve the bearing performance and prolong working life,contact mechanics of hollow cylindrical roller bearing of cone bit was simulated.Effects of hollow size,drilling pressure,friction coefficient and fitting clearance on mechanics performance of the bearing were studied.The results show that the maximum equivalent stress of the hollow cylindrical roller bearing appears on the claw journal,and the maximum contact stress appears on the contact pair of the hollow roller.Besides,hollow sizes have a greater impact on the equivalent stress and contact stress of the cylindrical roller,while the influence on the stress of the cone and claw journal is relatively small.With the increasing of the drilling pressure and fitting clearance,equivalent stress and contact stress of bearing parts increase.The friction coefficient has little impact on mechanical performance of the bearing.As the 121/4SWPI517 type hollow cylindrical roller bearing of cone bit an example,the optimal hollow size is 55%,the drilling pressure is 140 kN and the fitting clearance is 0e0.02 mm.展开更多
A role of tumor-suppressive activity of p53 in the tumor microenvironment(TME)has been implicated but remains fairly understudied.To address this knowledge gap,we leveraged our MdmxS314A mice as recipients to investig...A role of tumor-suppressive activity of p53 in the tumor microenvironment(TME)has been implicated but remains fairly understudied.To address this knowledge gap,we leveraged our MdmxS314A mice as recipients to investigate how implanted tumor cells incapacitate host p53 creating a conducive TME for tumor progression.We found that tumor cell-associated stress induced p53 downregulation in peritumor cells via an MDMX-Ser314 phosphorylation-dependent manner.As a result,an immunosuppressive TME was developed,as reflected by diminished immune cell infiltration into tumors and compromised macrophage M1 polarization.Remarkably,ablation of MDMX-Ser314 phosphorylation attenuated p53 decline in peritumor cells,which was associated with mitigation of immunosuppression and significant tumor growth delay.Our data collectively uncover a novel role of p53 in regulating the tumor immune microenvironment,suggesting that p53 restoration in the TME can be exploited as a potential strategy of anticancer therapy.展开更多
基金supported by the National Natural Science Foundation of China(NSFC:32260268)the Science and Technology Project of Guizhou Province[(2021)General-455]the Guizhou Hundred-level Innovative Talents Project[Qian-ke-he platform talents(2020)6004-2].
文摘Leaf trait networks(LTNs)visualize the intricate linkages reflecting plant trait-functional coordination.Typical karst vegetation,developed from lithological dolomite and limestone,generally exhibits differential communities,possibly due to habitat rock exposure,soil depth,and soil physicochemical properties variations,leading to a shift from plant trait variation to functional linkages.However,how soil and habitat quality affect the differentiation of leaf trait networks remains unclear.LTNs were constructed for typical dolomite and limestone habitats by analyzing twenty-one woody plant leaf traits across fifty-six forest subplots in karst mountains.The differences between dolomite and limestone LTNs were compared using network parameters.The network association of soil and habitat quality was analyzed using redundancy analysis(RDA),Mantle's test,and a random forest model.The limestone LTN exhibited significantly higher edge density with lower diameter and average path length when compared to the dolomite LTN.It indicates LTN differentiation,with the limestone network displaying a more compact architecture and higher connectivity than the dolomite network.The specific leaf phosphorus and leaf nitrogen contents of dolomite LTN,as well as the leaf mass and leaf carbon contents of limestone LTN,significantly contributed to network degree and closeness,serving as crucial node traits regulating LTN connectedness.Additionally,both habitat LTNs significantly correlated with soil nitrogen and phosphorus,stoichiometric ratios,pH,and organic carbon,as well as soil depth and rock exposure rates,with soil depth and rock exposure showing greater relative importance.Soil depth and rock exposure dominate trait network differentiation,with the limestone habitat exhibiting a more compact network architecture than the dolomite habitat.
基金supported by the JSPS KAKENHI(Grant numbers JP20H00288 and JP22K02136)
文摘Wearable triboelectric nanogenerators(TENGs)have attracted attention owing to their ability to harvest energy from the surrounding environment without maintenance.Herein,polyetherimide-Al_(2)O_(3)(PAl)and polyvinylidene fluoride-co-hexafluoropropylene(PVDF-HFP,PH)nanofiber membranes were used as tribo-positive and tribo-negative materials,respectively.Phytic acid-doped polyaniline(PANI)/cotton fabric(PPCF)and ethylenediamine(EDA)-crosslinked PAl(EPAl)nanofiber membranes were used as triboelectrode and triboencapsulation materials,respectively.The result showed that when the PAl-PH-based TENG was shaped as a circle with a radius of 1 cm,under the pressure of 50 N,and the frequency of 0.5 Hz,the open-circuit voltage(V_(oc))and short-circuit current(I_(sc))reached the highest value of 66.6 V and-93.4 to 110.1 nA,respectively.Moreover,the PH-based TENG could be used as a fabric sensor to detect fabric composition and as a sensor-inductive switch for light bulbs or beeping warning devices.When the PAl-PH-based TENG was shaped as a 5×5 cm^(2)rectangle,a 33 pF capacitor could be charged to 15 V in 28 s.Interestingly,compared to PAl nanofiber membranes,EPAl nanofiber membranes exhibited good dyeing properties and excellent solvent resistance.The PPCF exhibited<5%resistance change after washing,bending,and stretching.
基金funded by the National Natural Science Foundation of China (Grant no.32070223)the Biological Resources Programme,Chinese Academy of Sciences (Grant no.KFJ-BRP-017-19)
文摘Previous studies recognized three major lineages of the family Costaceae:a South American clade,an Asian clade and a Costus clade.However,the genus Hellenia within the Asian clade has been shown to be non-monophyletic and its morphology has not been studied carefully.Therefore,the complete plastid genomes of Hellenia species were obtained and the monophyly of Hellenia was tested through four different datasets in this study.Plastid phylogenomic analyses of Costaceae revealed that Hellenia is strongly supported as paraphyletic.Two major clades are recovered,namely the Hellenia s.s.subclade and the Parahellenia subclade.Phylogenetic analyses based on an enlarged taxon sampling of the Asian clade using a two chloroplast markers dataset(trnK intron and trnL-F spacer)confirmed the paraphyly of Hellenia.Meanwhile,morphological analyses suggested that members of the Parahellenia subclade differ from the remaining Hellenia species in many characters including inflorescences,bracts,stigma,axillary buds,floral tubes and labellum.According to the present molecular and morphological evidence,the latter subclade is recognized as a new genus,Parahellenia.Two new species are described,four new combinations are made,and identification keys are also provided.
基金the financial support from the National Natural Science Foundation of China(U1805254,21773192,22072117,22179112)。
文摘Lithium-oxygen(Li-O) battery is considered as one of the most promising alternatives because of its ultrahigh theoretical energy density. However, their cycling stability is severely restricted by the uncontrollable dendrite growth and serious oxygen corrosion issue on Li surface. Herein, a sulfur-modified Li surface can be successfully constructed via chemical reaction of guanylthiourea(GTU) molecule on Li,which can induce the selectively fast decomposition of lithium bis(trifluoromethanesulfonyl)imide(LiTFSI) to form a smooth and stable inorganics-rich solid-electrolyte interphase(IR-SEI) during the subsequent electrochemical process. Such an IR-SEI cannot only offer a highly reversible and stable Li plating/stripping chemistry with dendrite-free property(10 mA cm^(-2)-10 mAh cm^(-2), > 0.5 years;3 mA cm^(-2)-3 m Ah cm^(-2), > 1 year) but also endows the Li metal an anti-oxygen corrosion function, thereby significantly improving the cycling stability of Li-Obatteries. This work provides a new idea for constructing functional solid-electrolyte interphase(SEI) to achieve highly stable Li metal anode.
基金financially supported by the National Key Research and Development Program/Key Scientific Issues of Transformative Technology (2020YFA0710303)the National Natural Science Foundation of China (U1905215 and 52072076)+1 种基金Fujian Science Foundation Grant (2022J01554)the Key Project of Science and Technology Innovation of Fujian Provincial Department of Education (2022G02002)。
基金supported by the CAS Project for Young Scientists in Basic Research(Grant No.YSBR042)the National Natural Science Foundation of China(Grant Nos.12125508 and 11935020)+1 种基金the Program of Shanghai Academic/Technology Research Leader(Grant No.21XD1404100)the Shanghai Pilot Program for Basic Research of the Chinese Academy of Sciences,Shanghai Branch(Grant No.JCYJ-SHFY-2021-010).
文摘The spectroscopic methods for the ultrafast electronic and structural dynamics of materials require fully coherent extreme ultraviolet and soft X-ray radiation with high-average brightness.Seeded free-electron lasers(FELs)are ideal sources for delivering fully coherent soft X-ray pulses.However,due to state-of-theart laser system limitations,it is challenging to meet the ultraviolet seed laser’s requirements of sufficient energy modulation and high repetition rates simultaneously.The self-modulation scheme has been proposed and recently demonstrated in a seeded FEL to relax the seed laser requirements.Using numerical simulations,we show that the required seed laser intensity in the self-modulation is~3 orders of magnitude lower than that in the standard high-gain harmonic generation(HGHG).The harmonic self-modulation can launch a singlestage HGHG FEL lasing at the 30th harmonic of the seed laser.Moreover,the proof-of-principle experimental results confirm that the harmonic self-modulation can still amplify the laser-induced energy modulation.These achievements reveal that the self-modulation can not only remarkably reduce the requirements of the seed laser but also improve the harmonic upconversion efficiency,which paves the way for realizing high-repetitionrate and fully coherent soft X-ray FELs.
文摘X-ray beams carrying orbital angular momentum(OAM)are an emerging tool for probing matter.Optical elements,such as spiral phase plates and zone plates,have been widely used to generate OAM light.However,due to the high impinging intensities,these optics are challenging to use at X-ray free-electron lasers(XFELs).Here,we propose a self-seeded free-electron laser(FEL)method to produce intense X-ray vortices.Unlike passive filtering after amplification,an optical element will be used to introduce the helical phase to the radiation pulse in the linear regime,significantly reducing thermal load on the optical element.The generated OAM pulse is then used as a seed and significantly amplified.Theoretical analysis and numerical simulations demonstrate that the power of the OAM seed pulse can be amplified by more than two orders of magnitude,reaching peak powers of several tens of gigawatts.The proposed method paves the way for high-power and high-repetition-rate OAM pulses of XFEL light.
基金financially supported by the National Key Research and Development Program/Key Scientific Issues of Transformative Technology(2020YFA0710303)the National Natural Science Foundation of China(U1905215 and 52072076)+1 种基金Fujian Natural Science Foundation(2022J01554)the Key Project of Science and Technology Innovation of Fujian Provincial Department of Education(2022G02002)。
文摘ZBTB7A, a member of the POZ/BTB and Krüppel （POK） family of transcription factors, has been shown to have a context-dependent role in cancer development and progression. The role of ZBTB7A in estrogen receptor alpha （ERα）-positive breast cancer is largely unknown. Approximately 70% of breast cancers are classified as ERα-positive. ERα carries out the biological effects of estrogen and its expression level dictates response to endocrine therapies and prognosis for breast cancer patients. In this study, we find that ZBTB7A transcriptionally regulates ERα expression in ERα-positive breast cancer cell lines by binding to the ESR1 promoter leading to increased transcription of ERα. Inhibition of ZBTB7A in ERα-positive cells results in decreased estrogen responsiveness as demonstrated by diminished estrogen-response element-driven luciferase reporter activity, induction of estrogen target genes, and estrogen-stimulated growth. We also report that ERα potentiates ZBTB7A expression via a post-translational mechanism, suggesting the presence of a positive feedback loop between ZBTB7A and ERα, conferring sensitivity to estrogen in breast cancer. Clinically, we find that ZBTB7A and ERα are often co-expressed in breast cancers and that high ZBTB7A expression correlates with improved overall and relapse-free survival for breast cancer patients. Importantly, high ZBTB7A expression predicts a more favorable outcome for patients treated with endocrine therapies. Together, these findings demonstrate that ZBTB7A contributes to the transcriptional program maintaining ERα expression and potentially an endocrine therapy-responsive phenotype in breast cancer.
基金partially supported by the National Key Research and Development Program of China(Grant No.2018YFE0103100)the National Natural Science Foundation of China(Grant No.11935020)。
文摘As a new-generation light source,free-electron lasers(FELs)provide high-brightness x-ray pulses at the angstrom-femtosecond space and time scales.The fundamental physics behind the FEL is the interaction between an electromagnetic wave and a relativistic electron beam in an undulator,which consists of hundreds or thousands of dipole magnets with an alternating magnetic field.We report the first observation of the laser–beam interaction in a pure dipole magnet in which the electron beam energy modulation with a 40-ke V amplitude and a 266-nm period is measured.We demonstrate that such an energy modulation can be used to launch a seeded FEL,that is,lasing at the sixth harmonic of the seed laser in a high-gain harmonic generation scheme.The results reveal the most basic process of the FEL lasing and open up a new direction for the study and exploitation of laser–beam interactions.
基金supported by the National Natural Science Foundation of China(Grant No.32171892)
文摘Accurate wheat spike detection is crucial in wheat field phenotyping for precision farming.Advances in artificial intelligence have enabled deep learning models to improve the accuracy of detecting wheat spikes.However,wheat growth is a dynamic process characterized by important changes in the color feature of wheat spikes and the background.Existing models for wheat spike detection are typically designed for a specific growth stage.Their adaptability to other growth stages or field scenes is limited.Such models cannot detect wheat spikes accurately caused by the difference in color,size,and morphological features between growth stages.This paper proposes WheatNet to detect small and oriented wheat spikes from the filling to the maturity stage.WheatNet constructs a Transform Network to reduce the effect of differences in the color features of spikes at the filling and maturity stages on detection accuracy.Moreover,a Detection Network is designed to improve wheat spike detection capability.A Circle Smooth Label is proposed to classify wheat spike angles in drone imagery.A new micro-scale detection layer is added to the network to extract the features of small spikes.Localization loss is improved by Complete Intersection over Union to reduce the impact of the background.The results show that WheatNet can achieve greater accuracy than classical detection methods.The detection accuracy with average precision of spike detection at the filling stage is 90.1%,while it is 88.6%at the maturity stage.It suggests that WheatNet is a promising tool for detection of wheat spikes.
基金The authors gratefully acknowledge finance of this study that was supported by Science and Technology Innovation Talent Engineering Project of Sichuan Province(2014-025)Natural Science Foundation of China(51474180).
文摘Bearings are key components of cone bit,thus its rapid failure is a major cause of leading to lower life of the bit.To improve the bearing performance and prolong working life,contact mechanics of hollow cylindrical roller bearing of cone bit was simulated.Effects of hollow size,drilling pressure,friction coefficient and fitting clearance on mechanics performance of the bearing were studied.The results show that the maximum equivalent stress of the hollow cylindrical roller bearing appears on the claw journal,and the maximum contact stress appears on the contact pair of the hollow roller.Besides,hollow sizes have a greater impact on the equivalent stress and contact stress of the cylindrical roller,while the influence on the stress of the cone and claw journal is relatively small.With the increasing of the drilling pressure and fitting clearance,equivalent stress and contact stress of bearing parts increase.The friction coefficient has little impact on mechanical performance of the bearing.As the 121/4SWPI517 type hollow cylindrical roller bearing of cone bit an example,the optimal hollow size is 55%,the drilling pressure is 140 kN and the fitting clearance is 0e0.02 mm.
基金This work was supported in part by the Morningside Foundation,the Zhu Fund,and grants from the National Cancer Institute at the National Institutes of Health(RO1CA233558,R01CA167814,and R01CA125144)to Z.-M.Y.
文摘A role of tumor-suppressive activity of p53 in the tumor microenvironment(TME)has been implicated but remains fairly understudied.To address this knowledge gap,we leveraged our MdmxS314A mice as recipients to investigate how implanted tumor cells incapacitate host p53 creating a conducive TME for tumor progression.We found that tumor cell-associated stress induced p53 downregulation in peritumor cells via an MDMX-Ser314 phosphorylation-dependent manner.As a result,an immunosuppressive TME was developed,as reflected by diminished immune cell infiltration into tumors and compromised macrophage M1 polarization.Remarkably,ablation of MDMX-Ser314 phosphorylation attenuated p53 decline in peritumor cells,which was associated with mitigation of immunosuppression and significant tumor growth delay.Our data collectively uncover a novel role of p53 in regulating the tumor immune microenvironment,suggesting that p53 restoration in the TME can be exploited as a potential strategy of anticancer therapy.
