针对复合材料电池包下箱体的树脂传递模塑(Resin Transfer Molding,RTM)成型进行了方案设计,基于PAM-RTM软件对其充模过程进行仿真分析及孔隙缺陷预测。首先,对比了两种方案在三种出胶口状态下充模时间,分析了注胶压力及树脂黏度对RTM...针对复合材料电池包下箱体的树脂传递模塑(Resin Transfer Molding,RTM)成型进行了方案设计,基于PAM-RTM软件对其充模过程进行仿真分析及孔隙缺陷预测。首先,对比了两种方案在三种出胶口状态下充模时间,分析了注胶压力及树脂黏度对RTM成型时间的影响规律;其次,分析了充模过程中注胶口附近位置的压力变化情况;最后,预测了宏观/微观两种尺度孔隙缺陷在构件中分布及注胶压力对孔隙含量的影响规律,并结合流速优化理论控制树脂前沿流速以降低孔隙含量。结果表明,模腔内注胶与出胶口压力差越大,成型用时越少,且受到注胶位置影响。注胶压力与充模时间呈线性关系,压力越低,充模时间缩短效果越明显,且黏度越大,充模时间越长。孔隙含量与前沿流速有关,注胶压力越大导致流速越快,宏观孔隙随之减少,微观孔隙相应增多;且流速优化方式注胶能够显著降低总体孔隙率水平,但会延长成型周期。展开更多
树脂传递模塑成型(Resin transfer molding,RTM)工艺仿真对于提高成型质量,降低RTM工艺成本至关重要。将人工智能方法引入RTM工艺仿真中,可以不必求解复杂的多尺度渗流模型就能够获得对RTM模具设计的指导性意见。本文综述了以遗传算法...树脂传递模塑成型(Resin transfer molding,RTM)工艺仿真对于提高成型质量,降低RTM工艺成本至关重要。将人工智能方法引入RTM工艺仿真中,可以不必求解复杂的多尺度渗流模型就能够获得对RTM模具设计的指导性意见。本文综述了以遗传算法和机器学习方法为主的人工智能方法在RTM工艺仿真中的研究现状,并讨论了该领域存在的问题及发展方向。遗传算法主要被应用于注胶口及流道配置优化方面,但在复杂问题中收敛性较差,与其他局部搜索算法结合的方法展现出解决复杂问题的潜力;机器学习方法的应用研究处于起步阶段,目前主要被应用于注射压力、浸渍质量、渗透率预测等方面,只对简单二维充模问题进行了研究;其他人工智能方法通常计算成本低,但难以验证最优性。人工智能方法的问题集中在迭代/训练所需的数据集的获取成本方面。其在三维复杂几何结构及非均匀渗透率制件方面的应用是未来的重要发展方向。展开更多
Breast cancer(BRCA)is characterized by high heterogeneity,with aggressive subtypes frequently showing poor prognosis and resistance to conventional therapies,making the discovery of new therapeutic targets and strateg...Breast cancer(BRCA)is characterized by high heterogeneity,with aggressive subtypes frequently showing poor prognosis and resistance to conventional therapies,making the discovery of new therapeutic targets and strategies imperative.Although elevated expression of discs large homolog 3(DLG3)has been reported in BRCA,its functional role in disease progression remains unclear.We performed bioinformatic analyses of clinical datasets to evaluate the prognostic significance of DLG3 expression in BRCA patients.In vitro gain-and loss-of-function experiments were conducted to assess the impact of DLG3 on BRCA cell proliferation,migration,and colony formation.Transcriptomic profiling,coupled with pharmacological inhibition,was employed to identify and validate downstream signaling pathways.Additionally,we extended our validation to an in vivo model to assess the role of DLG3 in tumor progression.We found that elevated DLG3 levels correlated with poor prognosis in breast cancer patients.Functionally,DLG3 overexpression significantly promoted cell proliferation and migration in estrogen receptor-positive MCF7 and triple-negative MDA-MB-231 breast cancer cells,whereas its knockdown suppressed these effects.Transcriptomic analyses revealed that DLG3 activates signal transducer and activator of transcription 3(STAT3)signaling,a finding further corroborated by Western blot.Critically,treatment with the STAT3 inhibitor Stattic attenuated DLG3-driven proliferation and migration,supporting a DLG3-STAT3 oncogenic axis.Furthermore,in vivo studies validated the role of DLG3 in promoting tumor growth and its correlation with elevated STAT3 signaling,consistent with our in vitro findings.Our findings establish DLG3 as a novel driver of breast cancer progression that directly activates STAT3 signaling.DLG3 thus represents both a potential prognostic biomarker and a promising therapeutic target for aggressive breast cancer subtypes,including triple-negative breast cancer.展开更多
The radical addition/functional group migration strategy has emerged as a powerful tool for the difunctionalization of unsaturated hydrocarbons,yet the heteroatom-mediated functional group migration remains largely un...The radical addition/functional group migration strategy has emerged as a powerful tool for the difunctionalization of unsaturated hydrocarbons,yet the heteroatom-mediated functional group migration remains largely unexplored.Herein,we report an unprecedented radical difunctionalization of alkynes employing oxime esters as bifunctional reagents through a novel C-centered radical addition/N-centered radical translocation sequence.This innovative transformation paradigm enables efficient alkylamination of alkynes under mild photocatalytic redox conditions.Mechanistic investigations reveal a cascade sequence initiated by single-electron transfer from oxime derivatives,proceeding through radical addition,6-exo-trig cyclization,and subsequent imino group migration.展开更多
The published article titled“MicroRNA-133b Inhibits Proliferation,Cellular Migration,and Invasion via Targeting LASP1 in Hepatocarcinoma Cells”has been retracted from Oncology Research,Vol.25,No.8,2017,pp.1269–1282.
Adult neurogenesis continuously produces new neurons critical for cognitive plasticity in adult rodents.While it is known transforming growth factor-βsignaling is important in embryonic neurogenesis,its role in postn...Adult neurogenesis continuously produces new neurons critical for cognitive plasticity in adult rodents.While it is known transforming growth factor-βsignaling is important in embryonic neurogenesis,its role in postnatal neurogenesis remains unclear.In this study,to define the precise role of transforming growth factor-βsignaling in postnatal neurogenesis at distinct stages of the neurogenic cascade both in vitro and in vivo,we developed two novel inducible and cell type-specific mouse models to specifically silence transforming growth factor-βsignaling in neural stem cells in(mGFAPcre-ALK5fl/fl-Ai9)or immature neuroblasts in(DCXcreERT2-ALK5fl/fl-Ai9).Our data showed that exogenous transforming growth factor-βtreatment led to inhibition of the proliferation of primary neural stem cells while stimulating their migration.These effects were abolished in activin-like kinase 5(ALK5)knockout primary neural stem cells.Consistent with this,inhibition of transforming growth factor-βsignaling with SB-431542 in wild-type neural stem cells stimulated proliferation while inhibited the migration of neural stem cells.Interestingly,deletion of transforming growth factor-βreceptor in neural stem cells in vivo inhibited the migration of postnatal born neurons in mGFAPcre-ALK5fl/fl-Ai9 mice,while abolishment of transforming growth factor-βsignaling in immature neuroblasts in DCXcreERT2-ALK5fl/fl-Ai9 mice did not affect the migration of these cells in the hippocampus.In summary,our data supports a dual role of transforming growth factor-βsignaling in the proliferation and migration of neural stem cells in vitro.Moreover,our data provides novel insights on cell type-specific-dependent requirements of transforming growth factor-βsignaling on neural stem cell proliferation and migration in vivo.展开更多
In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly...In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration.展开更多
As the primary functional component of a fusion reactor,the fusion blanket pebble bed,composed of numerous particles,is crucial for tritium breeding,neutron multiplication,and radiation shielding.Particles within trit...As the primary functional component of a fusion reactor,the fusion blanket pebble bed,composed of numerous particles,is crucial for tritium breeding,neutron multiplication,and radiation shielding.Particles within tritium-breeding pebble beds are subjected to prolonged neutron irradiation,high thermal loads,and strong magnetic fields in fusion environments.Such conditions render them susceptible to pulverization and fragmentation.The resulting fragments and powders migrate and are deposited into the gas channel,driven by the purge gas.The reduction in the effective flow area of the gas increases the flow resistance,resulting in tritium retention,degraded heat transfer,and other adverse effects.These conditions impair the thermodynamic properties of the pebble beds and hinder the self-maintenance of tritium.Limited information exists on powder migration and clogging mechanisms in fusion blanket pebble beds,particularly under diverse physical conditions.The aim of this study was to use a computational fluid dynamics model coupled with the discrete element method(CFD-DEM)to numerically explore powder migration and clogging in pebble beds.The model considers factors such as breeder orientation,purge velocity,powder size distribution,and friction coefficient.We propose two migration and clogging mechanisms.One involves powder with a large particle size,and the other does not.The results indicate that the powder migration velocity progresses through three stages:rapid decay,linear decay,and stability.Pebble-bed clogging manifests in two forms:extensive superficial clogging and uniform internal clogging.Two fitted curves were used to depict the migration and clogging tendencies.The powder size distribution significantly influenced the powder migration.The breeder orientation,powder size,and friction coefficient affected the distribution of the clogging powders.However,the impact of the purge velocity on powder migration and clogging in pebble beds was limited,and this effect varied significantly with different particle size ratios.Based on the analysis,a formula is proposed to characterize the behavior of the powder in the pebble beds.The results of this study can aid in analyzing and predicting powder dynamics in pebble beds.展开更多
本文公开了一种适用于HP-RTM(High Pressure Resin Transfer Molding)工艺的高强度阻燃环氧树脂组合物,包含A、B两个组分,其中A组分包含基体树脂、阻燃剂、稀释剂和助剂,B组分包含胺类固化剂和促进剂,阻燃剂为磷酸酯类化合物和四溴双酚...本文公开了一种适用于HP-RTM(High Pressure Resin Transfer Molding)工艺的高强度阻燃环氧树脂组合物,包含A、B两个组分,其中A组分包含基体树脂、阻燃剂、稀释剂和助剂,B组分包含胺类固化剂和促进剂,阻燃剂为磷酸酯类化合物和四溴双酚A环氧树脂的组合物。研究了基体树脂、阻燃剂、稀释剂的种类和含量对HP-RTM环氧树脂强度和阻燃性的影响,以及胺类固化剂的种类和含量对HP-RTM环氧树脂凝胶时间的影响。结果表明,基体树脂、反应型阻燃剂、稀释剂对力学强度共同影响,阻燃剂对阻燃性能起主要影响作用,固化剂对凝胶时间起主要影响作用。展开更多
Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment...Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment,the firstproblem to be solved is how to introduce and retain the bacterial cells in the soil,which involves the migration and retention of bacterial cells during the biogrouting process.Soil particle size,a key factor in determining pore throat size,can have a significanteffect on the migration and retention of bacterial cells in the soil and therefore on biomineralization.To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization,two sets of tests were carried out in this study,including percolation tests and sand column treatment tests.Soil urease activity(definedas urease activity per unit mass of soil)and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand.The results indicate that sands with a particle size smaller than 0.25 mmwould inhibit the migration of bacteria in the sand,resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization.On the other hand,sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand,resulting in low calcium conversion efficiency.Meanwhile,particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size,and thus biomineralization.展开更多
Peripheral nerve defect repair is a complex process that involves multiple cell types;perineurial cells play a pivotal role.Hair follicle neural crest stem cells promote perineurial cell proliferation and migration vi...Peripheral nerve defect repair is a complex process that involves multiple cell types;perineurial cells play a pivotal role.Hair follicle neural crest stem cells promote perineurial cell proliferation and migration via paracrine signaling;however,their clinical applications are limited by potential risks such as tumorigenesis and xenogeneic immune rejection,which are similar to the risks associated with other stem cell transplantations.The present study therefore focuses on small extracellular vesicles derived from hair follicle neural crest stem cells,which preserve the bioactive properties of the parent cells while avoiding the transplantation-associated risks.In vitro,small extracellular vesicles derived from hair follicle neural crest stem cells significantly enhanced the proliferation,migration,tube formation,and barrier function of perineurial cells,and subsequently upregulated the expression of tight junction proteins.Furthermore,in a rat model of sciatic nerve defects bridged with silicon tubes,treatment with small extracellular vesicles derived from hair follicle neural crest stem cells resulted in higher tight junction protein expression in perineurial cells,thus facilitating neural tissue regeneration.At 10 weeks post-surgery,rats treated with small extracellular vesicles derived from hair follicle neural crest stem cells exhibited improved nerve function recovery and reduced muscle atrophy.Transcriptomic and micro RNA analyses revealed that small extracellular vesicles derived from hair follicle neural crest stem cells deliver mi R-21-5p,which inhibits mothers against decapentaplegic homolog 7 expression,thereby activating the transforming growth factor-β/mothers against decapentaplegic homolog signaling pathway and upregulating hyaluronan synthase 2 expression,and further enhancing tight junction protein expression.Together,our findings indicate that small extracellular vesicles derived from hair follicle neural crest stem cells promote the proliferation,migration,and tight junction protein formation of perineurial cells.These results provide new insights into peripheral nerve regeneration from the perspective of perineurial cells,and present a novel approach for the clinical treatment of peripheral nerve defects.展开更多
Severe fever with thrombocytopenia syndrome virus(SFTSV),the causative agent of a febrile human disease,was first identified from central and eastern provinces in China,and later in Japan and South Korea.Hubei Provinc...Severe fever with thrombocytopenia syndrome virus(SFTSV),the causative agent of a febrile human disease,was first identified from central and eastern provinces in China,and later in Japan and South Korea.Hubei Province is one of the major SFTS epidemic areas in the central part of China.This study reported the isolation of 11 new SFTSV strains from patients in Hubei Province collected in 2017.Extensive phylogenetic analyses were conducted based on the complete coding sequences of SFTSV segments including the new strains.It was suggested that five different SFTSV genotypes were circulating in Hubei,and 15 reassortment patterns and migration pathways correlated with each genotype were identified,which was more than previously recognized.Hubei Province was more involved in the evolutionary events of SFTSV than that previously thought in which the evolutionary events of SFTSV were reported to be independent from those in other epidemic regions.Further divergence of SFTSV strains was suggested by pairwise comparison of SFTSV sequences from each genotype and sequence identity normalized to representative strain in genotype C1.Subsequently,amino acid variations specific for genotype(s),strain(s),or cluster(s)were inspected,which may be related to differential biological activity of SFTSV strains/genotypes.In conclusion,we analyzed the current status of SFTSV phylogeny in Hubei Province and discussed the possible events correlated to SFTSV evolution.It provided an in-depth insight into SFTSV evolution,raising concerns for the use of proper SFTSV strains in future studies.展开更多
文摘针对复合材料电池包下箱体的树脂传递模塑(Resin Transfer Molding,RTM)成型进行了方案设计,基于PAM-RTM软件对其充模过程进行仿真分析及孔隙缺陷预测。首先,对比了两种方案在三种出胶口状态下充模时间,分析了注胶压力及树脂黏度对RTM成型时间的影响规律;其次,分析了充模过程中注胶口附近位置的压力变化情况;最后,预测了宏观/微观两种尺度孔隙缺陷在构件中分布及注胶压力对孔隙含量的影响规律,并结合流速优化理论控制树脂前沿流速以降低孔隙含量。结果表明,模腔内注胶与出胶口压力差越大,成型用时越少,且受到注胶位置影响。注胶压力与充模时间呈线性关系,压力越低,充模时间缩短效果越明显,且黏度越大,充模时间越长。孔隙含量与前沿流速有关,注胶压力越大导致流速越快,宏观孔隙随之减少,微观孔隙相应增多;且流速优化方式注胶能够显著降低总体孔隙率水平,但会延长成型周期。
文摘树脂传递模塑成型(Resin transfer molding,RTM)工艺仿真对于提高成型质量,降低RTM工艺成本至关重要。将人工智能方法引入RTM工艺仿真中,可以不必求解复杂的多尺度渗流模型就能够获得对RTM模具设计的指导性意见。本文综述了以遗传算法和机器学习方法为主的人工智能方法在RTM工艺仿真中的研究现状,并讨论了该领域存在的问题及发展方向。遗传算法主要被应用于注胶口及流道配置优化方面,但在复杂问题中收敛性较差,与其他局部搜索算法结合的方法展现出解决复杂问题的潜力;机器学习方法的应用研究处于起步阶段,目前主要被应用于注射压力、浸渍质量、渗透率预测等方面,只对简单二维充模问题进行了研究;其他人工智能方法通常计算成本低,但难以验证最优性。人工智能方法的问题集中在迭代/训练所需的数据集的获取成本方面。其在三维复杂几何结构及非均匀渗透率制件方面的应用是未来的重要发展方向。
文摘Breast cancer(BRCA)is characterized by high heterogeneity,with aggressive subtypes frequently showing poor prognosis and resistance to conventional therapies,making the discovery of new therapeutic targets and strategies imperative.Although elevated expression of discs large homolog 3(DLG3)has been reported in BRCA,its functional role in disease progression remains unclear.We performed bioinformatic analyses of clinical datasets to evaluate the prognostic significance of DLG3 expression in BRCA patients.In vitro gain-and loss-of-function experiments were conducted to assess the impact of DLG3 on BRCA cell proliferation,migration,and colony formation.Transcriptomic profiling,coupled with pharmacological inhibition,was employed to identify and validate downstream signaling pathways.Additionally,we extended our validation to an in vivo model to assess the role of DLG3 in tumor progression.We found that elevated DLG3 levels correlated with poor prognosis in breast cancer patients.Functionally,DLG3 overexpression significantly promoted cell proliferation and migration in estrogen receptor-positive MCF7 and triple-negative MDA-MB-231 breast cancer cells,whereas its knockdown suppressed these effects.Transcriptomic analyses revealed that DLG3 activates signal transducer and activator of transcription 3(STAT3)signaling,a finding further corroborated by Western blot.Critically,treatment with the STAT3 inhibitor Stattic attenuated DLG3-driven proliferation and migration,supporting a DLG3-STAT3 oncogenic axis.Furthermore,in vivo studies validated the role of DLG3 in promoting tumor growth and its correlation with elevated STAT3 signaling,consistent with our in vitro findings.Our findings establish DLG3 as a novel driver of breast cancer progression that directly activates STAT3 signaling.DLG3 thus represents both a potential prognostic biomarker and a promising therapeutic target for aggressive breast cancer subtypes,including triple-negative breast cancer.
基金supported by the Shaanxi Provincial Natural Science Basic Research Plan(2025JC-YBMS-114)the National Key Research and Development Program of China(2024YFB3212500)+1 种基金the Xi’an Jiaotong University(7121192002)the Fundamental Research Funds for the Central Universities(xzy022024023)。
文摘The radical addition/functional group migration strategy has emerged as a powerful tool for the difunctionalization of unsaturated hydrocarbons,yet the heteroatom-mediated functional group migration remains largely unexplored.Herein,we report an unprecedented radical difunctionalization of alkynes employing oxime esters as bifunctional reagents through a novel C-centered radical addition/N-centered radical translocation sequence.This innovative transformation paradigm enables efficient alkylamination of alkynes under mild photocatalytic redox conditions.Mechanistic investigations reveal a cascade sequence initiated by single-electron transfer from oxime derivatives,proceeding through radical addition,6-exo-trig cyclization,and subsequent imino group migration.
文摘The published article titled“MicroRNA-133b Inhibits Proliferation,Cellular Migration,and Invasion via Targeting LASP1 in Hepatocarcinoma Cells”has been retracted from Oncology Research,Vol.25,No.8,2017,pp.1269–1282.
基金supported by NIH grants,Nos.R01NS125074,R01AG083164,R01NS107365,and R21NS127177(to YL),1F31NS129204-01A1(to KW)and Albert Ryan Fellowship(to KW).
文摘Adult neurogenesis continuously produces new neurons critical for cognitive plasticity in adult rodents.While it is known transforming growth factor-βsignaling is important in embryonic neurogenesis,its role in postnatal neurogenesis remains unclear.In this study,to define the precise role of transforming growth factor-βsignaling in postnatal neurogenesis at distinct stages of the neurogenic cascade both in vitro and in vivo,we developed two novel inducible and cell type-specific mouse models to specifically silence transforming growth factor-βsignaling in neural stem cells in(mGFAPcre-ALK5fl/fl-Ai9)or immature neuroblasts in(DCXcreERT2-ALK5fl/fl-Ai9).Our data showed that exogenous transforming growth factor-βtreatment led to inhibition of the proliferation of primary neural stem cells while stimulating their migration.These effects were abolished in activin-like kinase 5(ALK5)knockout primary neural stem cells.Consistent with this,inhibition of transforming growth factor-βsignaling with SB-431542 in wild-type neural stem cells stimulated proliferation while inhibited the migration of neural stem cells.Interestingly,deletion of transforming growth factor-βreceptor in neural stem cells in vivo inhibited the migration of postnatal born neurons in mGFAPcre-ALK5fl/fl-Ai9 mice,while abolishment of transforming growth factor-βsignaling in immature neuroblasts in DCXcreERT2-ALK5fl/fl-Ai9 mice did not affect the migration of these cells in the hippocampus.In summary,our data supports a dual role of transforming growth factor-βsignaling in the proliferation and migration of neural stem cells in vitro.Moreover,our data provides novel insights on cell type-specific-dependent requirements of transforming growth factor-βsignaling on neural stem cell proliferation and migration in vivo.
基金supported by the National Natural Science Foundation of China(42430303)Strategy Priority Research Program(Category B)of the Chinese Academy of Sciences(XDB0710000)+2 种基金National Natural Science Foundation of China(42288201)the National Key R&D Program of China(2023YFF0803203)the IGGCAS start-up funding(Grant No.E251510101).
文摘In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration.
文摘As the primary functional component of a fusion reactor,the fusion blanket pebble bed,composed of numerous particles,is crucial for tritium breeding,neutron multiplication,and radiation shielding.Particles within tritium-breeding pebble beds are subjected to prolonged neutron irradiation,high thermal loads,and strong magnetic fields in fusion environments.Such conditions render them susceptible to pulverization and fragmentation.The resulting fragments and powders migrate and are deposited into the gas channel,driven by the purge gas.The reduction in the effective flow area of the gas increases the flow resistance,resulting in tritium retention,degraded heat transfer,and other adverse effects.These conditions impair the thermodynamic properties of the pebble beds and hinder the self-maintenance of tritium.Limited information exists on powder migration and clogging mechanisms in fusion blanket pebble beds,particularly under diverse physical conditions.The aim of this study was to use a computational fluid dynamics model coupled with the discrete element method(CFD-DEM)to numerically explore powder migration and clogging in pebble beds.The model considers factors such as breeder orientation,purge velocity,powder size distribution,and friction coefficient.We propose two migration and clogging mechanisms.One involves powder with a large particle size,and the other does not.The results indicate that the powder migration velocity progresses through three stages:rapid decay,linear decay,and stability.Pebble-bed clogging manifests in two forms:extensive superficial clogging and uniform internal clogging.Two fitted curves were used to depict the migration and clogging tendencies.The powder size distribution significantly influenced the powder migration.The breeder orientation,powder size,and friction coefficient affected the distribution of the clogging powders.However,the impact of the purge velocity on powder migration and clogging in pebble beds was limited,and this effect varied significantly with different particle size ratios.Based on the analysis,a formula is proposed to characterize the behavior of the powder in the pebble beds.The results of this study can aid in analyzing and predicting powder dynamics in pebble beds.
文摘本文公开了一种适用于HP-RTM(High Pressure Resin Transfer Molding)工艺的高强度阻燃环氧树脂组合物,包含A、B两个组分,其中A组分包含基体树脂、阻燃剂、稀释剂和助剂,B组分包含胺类固化剂和促进剂,阻燃剂为磷酸酯类化合物和四溴双酚A环氧树脂的组合物。研究了基体树脂、阻燃剂、稀释剂的种类和含量对HP-RTM环氧树脂强度和阻燃性的影响,以及胺类固化剂的种类和含量对HP-RTM环氧树脂凝胶时间的影响。结果表明,基体树脂、反应型阻燃剂、稀释剂对力学强度共同影响,阻燃剂对阻燃性能起主要影响作用,固化剂对凝胶时间起主要影响作用。
基金support by the National Natural Science Foundation of China(NSFC)(Grant Nos.52178319,42477160,52338007).
文摘Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation(MICP)process.For MICP-based insitu biotreatment,the firstproblem to be solved is how to introduce and retain the bacterial cells in the soil,which involves the migration and retention of bacterial cells during the biogrouting process.Soil particle size,a key factor in determining pore throat size,can have a significanteffect on the migration and retention of bacterial cells in the soil and therefore on biomineralization.To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization,two sets of tests were carried out in this study,including percolation tests and sand column treatment tests.Soil urease activity(definedas urease activity per unit mass of soil)and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand.The results indicate that sands with a particle size smaller than 0.25 mmwould inhibit the migration of bacteria in the sand,resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization.On the other hand,sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand,resulting in low calcium conversion efficiency.Meanwhile,particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size,and thus biomineralization.
基金supported by the National Natural Science Foundation of China,No.81571211(to FL)the Natural Science Foundation of Shanghai,No.22ZR1476800(to CH)。
文摘Peripheral nerve defect repair is a complex process that involves multiple cell types;perineurial cells play a pivotal role.Hair follicle neural crest stem cells promote perineurial cell proliferation and migration via paracrine signaling;however,their clinical applications are limited by potential risks such as tumorigenesis and xenogeneic immune rejection,which are similar to the risks associated with other stem cell transplantations.The present study therefore focuses on small extracellular vesicles derived from hair follicle neural crest stem cells,which preserve the bioactive properties of the parent cells while avoiding the transplantation-associated risks.In vitro,small extracellular vesicles derived from hair follicle neural crest stem cells significantly enhanced the proliferation,migration,tube formation,and barrier function of perineurial cells,and subsequently upregulated the expression of tight junction proteins.Furthermore,in a rat model of sciatic nerve defects bridged with silicon tubes,treatment with small extracellular vesicles derived from hair follicle neural crest stem cells resulted in higher tight junction protein expression in perineurial cells,thus facilitating neural tissue regeneration.At 10 weeks post-surgery,rats treated with small extracellular vesicles derived from hair follicle neural crest stem cells exhibited improved nerve function recovery and reduced muscle atrophy.Transcriptomic and micro RNA analyses revealed that small extracellular vesicles derived from hair follicle neural crest stem cells deliver mi R-21-5p,which inhibits mothers against decapentaplegic homolog 7 expression,thereby activating the transforming growth factor-β/mothers against decapentaplegic homolog signaling pathway and upregulating hyaluronan synthase 2 expression,and further enhancing tight junction protein expression.Together,our findings indicate that small extracellular vesicles derived from hair follicle neural crest stem cells promote the proliferation,migration,and tight junction protein formation of perineurial cells.These results provide new insights into peripheral nerve regeneration from the perspective of perineurial cells,and present a novel approach for the clinical treatment of peripheral nerve defects.
基金supported by the National Key R&D Programme of China(2018ZX10734404-010)the Nature Science Foundation of Hubei Province(2019CFB790 and 2018CFB471)+2 种基金the Innovation Team Project of Hubei Provincial Health Commission(WJ2019C003)the Open Research Fund of State Key Laboratory of Virology(2018IOV004)the Special Project of Technical Conditions(2060503)。
文摘Severe fever with thrombocytopenia syndrome virus(SFTSV),the causative agent of a febrile human disease,was first identified from central and eastern provinces in China,and later in Japan and South Korea.Hubei Province is one of the major SFTS epidemic areas in the central part of China.This study reported the isolation of 11 new SFTSV strains from patients in Hubei Province collected in 2017.Extensive phylogenetic analyses were conducted based on the complete coding sequences of SFTSV segments including the new strains.It was suggested that five different SFTSV genotypes were circulating in Hubei,and 15 reassortment patterns and migration pathways correlated with each genotype were identified,which was more than previously recognized.Hubei Province was more involved in the evolutionary events of SFTSV than that previously thought in which the evolutionary events of SFTSV were reported to be independent from those in other epidemic regions.Further divergence of SFTSV strains was suggested by pairwise comparison of SFTSV sequences from each genotype and sequence identity normalized to representative strain in genotype C1.Subsequently,amino acid variations specific for genotype(s),strain(s),or cluster(s)were inspected,which may be related to differential biological activity of SFTSV strains/genotypes.In conclusion,we analyzed the current status of SFTSV phylogeny in Hubei Province and discussed the possible events correlated to SFTSV evolution.It provided an in-depth insight into SFTSV evolution,raising concerns for the use of proper SFTSV strains in future studies.
