Rockburst precursors are critical for disaster warning,yet the complexity of rockburst has hindered the identification of a unified precursor.Furthermore,the influence of loading rates(LRs)on acoustic emission(AE)prec...Rockburst precursors are critical for disaster warning,yet the complexity of rockburst has hindered the identification of a unified precursor.Furthermore,the influence of loading rates(LRs)on acoustic emission(AE)precursors in different rock types remains poorly understood.This study investigates the AE characteristics and early warning times of rockburst in slate and mica-schist under four LRs(0.05,0.15,0.25,and 0.5 MPa/s)using true triaxial unloading tests.The micro-crack state of the samples was evaluated using entropy,while critical slowing down(CSD)theory was applied to interpret AE precursors.The results reveal that as the LR increases,the rockburst stress of both rocks initially rises and then declines,with mica-schist exhibiting more severe damage and a higher dominance of tensile cracks.Notably,identifying rockburst precursors in mica-schist proved more challenging compared to slate.Among the methods tested,AE amplitude variance outperformed entropy in precursor identification.Additionally,the rockburst early warning time was found to be negatively correlated with the LR,with mica-schist consistently showing shorter warning times than slate.The CSD-derived precursor,due to its enhanced sensitivity,is recommended for early warning systems.These findings provide new insights into the role of LRs in rockburst dynamics and offer practical guidance for improving precursor identification and disaster mitigation strategies.展开更多
Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechani...Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechanical properties of carbon fibers, and therefore affect the overall performance of pultruded composites. This study systematically investigated the influence of PAN precursor properties on the degree of graphitization, surface morphology and mechanical properties of carbon fibers by regulating the molecular weight distribution, stretching ratio and impurity content of PAN precursor, and analyzed the mechanism of action of carbon fiber properties on the interfacial bonding strength and tensile/ bending properties of composites in combination with the pultrusion process. The results showed that when the filament stretchability was increased to 4.5 times, the axial orientation of carbon fibers increased by 18% and the tensile strength reached 520 MPa;Filaments with impurity content below 0.3% increase carbon fiber yield by 5.2% and interlaminar shear strength of composites by 23%. This study provides a theoretical basis for raw material screening and process optimization of high-performance carbon fibers and their composites.展开更多
The increasing sophistication of cyberattacks,coupled with the limitations of rule-based detection systems,underscores the urgent need for proactive and intelligent cybersecurity solutions.Traditional intrusion detect...The increasing sophistication of cyberattacks,coupled with the limitations of rule-based detection systems,underscores the urgent need for proactive and intelligent cybersecurity solutions.Traditional intrusion detection systems often struggle with detecting early-stage threats,particularly in dynamic environments such as IoT,SDNs,and cloud infrastructures.These systems are hindered by high false positive rates,poor adaptability to evolving threats,and reliance on large labeled datasets.To address these challenges,this paper introduces CyberGuard-X,an AI-driven framework designed to identify attack precursors—subtle indicators of malicious intent—before full-scale intrusions occur.CyberGuard-X integrates anomaly detection,time-series analysis,and multi-stage classification within a scalable architecture.The model leverages deep learning techniques such as autoencoders,LSTM networks,and Transformer layers,supported by semi-supervised learning to enhance detection of zero-day and rare threats.Extensive experiments on benchmark datasets(CICIDS2017,CSE-CIC-IDS2018,and UNSW-NB15)demonstrate strong results,including 96.1%accuracy,94.7%precision,and 95.3%recall,while achieving a zero-day detection rate of 84.5%.With an inference time of 12.8 ms and 34.5%latency reduction,the model supports real-time deployment in resource-constrained environments.CyberGuard-X not only surpasses baseline models like LSTM and Random Forest but also enhances proactive threat mitigation across diverse network settings.展开更多
This study investigates the instability characteristics of dynamic disasters resulting from disruption caused by extracting resources underground. Utilizing the split Hopkinson pressure bar (SHPB) system, the dynamic ...This study investigates the instability characteristics of dynamic disasters resulting from disruption caused by extracting resources underground. Utilizing the split Hopkinson pressure bar (SHPB) system, the dynamic response mechanism of coal energy evolution is examined, and the energy instability criterion is established. The validity of the instability criterion is explored from the standpoint of damage progression. The results demonstrate that the energy conversion mechanism undergoes a fundamental alternation under impact disturbance. Moreover, the energy release rate as well as the energy dissipation rate undergo comparable changes across distinct levels of impact disturbance. The distinction between the energy release rate and the energy dissipation rate (DRD) increases as coal mass deformation grows. Prior to coal facing instability and failure, the DRD experienced an inflection point followed by a sharp decrease. In conjunction with the discussion on the damage evolution, the physical and mechanical significance of DRD remains clear, which can essentially describe the whole impact loading process. The phenomenon that the inflection point appears and DRD subsequently suddenly decreases can be employed as the energy criterion prior to the failure of instability. Furthermore, this paper provides significant reference for the prediction of dynamic instability of coal under dynamic disturbance.展开更多
The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields(<40 wt.%)due to the challenges in integrating significant amounts of boron,which ha...The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields(<40 wt.%)due to the challenges in integrating significant amounts of boron,which hampers their conversion into boride-based ultrahigh temperature ceramics.To tackle these challenges,a serious of pioneering liquid multi-component hafnium-containing ceramic SiHfCB precursors(with different Hf/Si ratios)have been developed.These novel precursors are featured with stable molec-ular structure and high ceramic yield which were successfully created through a novel one-pot polymer-ization process.They present in liquid form and their structure is characterized by C-C bonds forming its main chain with branched chains of O-Si-O,Si-O-Hf,Si-O-B,and B-O-Hf which have untapped advantages including uniform component dispersion,and excellent fluidity.The ceramic yield of SiHfCB precursor with Hf/Si of 0.2 is remarkably up to 68.6 wt.%at 1500℃,and their Hf content exceeded 50 wt.%.Of particular interest,the pyrolyzed product HfB_(2)-SiC nanopowders derived from the SiHfCB precursor with Hf/Si of 0.2,consist of nanopowders in the 40-60 nm range with a density of 5.23 g cm^(−3).Remarkably,this material demonstrates exceptional performance in ultrahigh temperature oxygen-containing environ-ments at 2500℃,showing near-zero ablation with a linear ablation rate of just 2.5×10^(−4) mm s^(−1).Post-ablation analysis of the microstructure reveals that the formation of a lava-like HfO_(2) and HfO_(2)-SiO_(2) oxide layer effectively blocks oxygen penetration and provides excellent oxidation resistance.The inno-vative SiHfCB hafnium-containing ceramic precursor offers a groundbreaking solution for the preparation of lightweight ultrahigh-temperature ceramics.This development is poised to provide robust technical support for the use of ultrahigh temperature ceramics in non-ablative thermal protective systems,partic-ularly in the construction of hypersonic vehicles,where ultrahigh temperature resilience is crucial.展开更多
Metal composites produced through the liquid metal dealloying(LMD)process feature an advanced matrix-matrix composite structure,where two metallic materials form a continuous,three-dimensional interconnected network.T...Metal composites produced through the liquid metal dealloying(LMD)process feature an advanced matrix-matrix composite structure,where two metallic materials form a continuous,three-dimensional interconnected network.This study investigates the effects of Ti Cu precursor compositions on dealloying behavior and microstructural evolution in liquid Mg,using Ti_(50)Cu_(50)and Ti_(30)Cu_(70)precursors.The initial microstructure of the precursor significantly influences dealloying kinetics and phase transitions.The single-phase Ti_(50)Cu_(50)precursor exhibits a faster initial dealloying rate due to its homogeneous structure,yet complete dealloying requires 90 min.In contrast,the dualphase Ti_(30)Cu_(70)precursor achieves complete dealloying in 30 min,demonstrating the impact of a higher Cu concentration on accelerating the process kinetics.Additionally,the study explores the coarsening behavior and hardness variations during the LMD process,along with the microstructural characteristics of Mg-Ti composites fabricated from these two precursors.The findings highlight the critical role of precursor composition in tailoring the microstructure and properties of Mg-Ti composites produced through the LMD process,demonstrating its potential for advanced composite material manufacturing.展开更多
The growing environmental awareness,the search for alternatives to fossil resources,and the goal of achieving a circular economy have all contributed to the increasing valorization of biowaste to produce bio-based pol...The growing environmental awareness,the search for alternatives to fossil resources,and the goal of achieving a circular economy have all contributed to the increasing valorization of biowaste to produce bio-based polymers and other high-value products.Among the various biowaste materials,lignin has gained significant attention due to its high aromatic carbon content,low cost,and abundance.Lignin is predominantly sourced as a byproduct from the paper industry,available in large quantities from hardwood and softwood,with variations in chemical structure and susceptibility to hydrolysis.This study focuses on softwood lignin obtained through the LignoForce^(TM) technology,comparing the thermal and chemical characteristics,and stability,of a recently produced batch with that of a batch that has been stored for four years.Additionally,the development of lignin-based thermoplastic polymer mixtures using Polyethylene Terephthalate Glycol(PET-G)and a blend of Polycarbonate and Acrylonitrile-Butadiene-Styrene(PC/ABS)with high lignin content(50–60 wt%)is explored,as well as the production of filaments for carbon fiber production.For this purpose,following melt mixing,the lignin-based mixtures were spun into filaments,which were subsequently subjected to thermal stabilization in an oxidative atmosphere.The lignin phase was well distributed in the PET-Gmatrix and the twomaterials presented a good interface,which further improved after thermal treatment under an oxidative atmosphere.After thermal treatment an increase in tensile modulus,tensile strength,and elongation at break of approximately 160%,200%,and 100%,respectively,was observed,confirming the good interface established,and consistent with structural changes such as cross-linking.Conversely,the PC/ABS blend did not form a good interface with the lignin domains after melt mixing.Although the interactions improved after thermal treatment,the tensile strength and elongation at break decreased by approximately 30%,while themodulus increased by approximately 20%.Overall,the good processability of the lignin/polymer mixtures into filaments,and their physical,chemical,and mechanical characterization before and after thermal oxidation are good indicators of the potential as precursors for carbon fiber production.展开更多
Bone resorption by osteoclasts is a critical step in bone remodeling,a process important for maintaining bone homeostasis and repairing injured bone.We previously identified a bone marrow mesenchymal subpopulation,mar...Bone resorption by osteoclasts is a critical step in bone remodeling,a process important for maintaining bone homeostasis and repairing injured bone.We previously identified a bone marrow mesenchymal subpopulation,marrow adipogenic lineage precursors(MALPs),and showed that its production of RANKL stimulates bone resorption in young mice using Adipoq-Cre.To exclude developmental defects and to investigate the role of MALPs-derived RANKL in adult bone,we generated inducible reporter mice(Adipoq-CreER Tomato)and RANKL deficient mice(Adipoq-CreER RANKLflox/flox,iCKO).Single cell-RNA sequencing data analysis and lineage tracing revealed that Adipoq+cells contain not only MALPs but also some mesenchymal progenitors capable of osteogenic differentiation.In situ hybridization showed that RANKL mRNA is only detected in MALPs,but not in osteogenic cells.RANKL deficiency in MALPs induced at 3 months of age rapidly increased trabecular bone mass in long bones as well as vertebrae due to diminished bone resorption but had no effect on the cortical bone.Ovariectomy(OVX)induced trabecular bone loss at both sites.RANKL depletion either before OVX or at 6 weeks post OVX protected and restored trabecular bone mass.Furthermore,bone healing after drill-hole injury was delayed in iCKO mice.Together,our findings demonstrate that MALPs play a dominant role in controlling trabecular bone resorption and that RANKL from MALPs is essential for trabecular bone turnover in adult bone homeostasis,postmenopausal bone loss,and injury repair.展开更多
INTRODUCTION.On May 1st,2024,around 2:10 a.m.,a catastrophic collapse occurred along the Meilong Expressway near Meizhou City,Guangdong Province,China,at coordinates 24°29′24″N and 116°40′25″E.This colla...INTRODUCTION.On May 1st,2024,around 2:10 a.m.,a catastrophic collapse occurred along the Meilong Expressway near Meizhou City,Guangdong Province,China,at coordinates 24°29′24″N and 116°40′25″E.This collapse resulted in a pavement failure of approximately 17.9 m in length and covering an area of about 184.3 m^(2)(Chinanews,2024).展开更多
Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection...Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.展开更多
Objective To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A(SV2A)influences the distribution of amyloid precursor protein(APP)in the trans-Golgi network(TGN),endolysosomal system...Objective To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A(SV2A)influences the distribution of amyloid precursor protein(APP)in the trans-Golgi network(TGN),endolysosomal system,and cell membranes and to reveal the effects of SV2A on APP amyloid degradation.Methods Colocalization analysis of APP with specific tagged proteins in the TGN,ensolysosomal system,and cell membrane was performed to explore the effects of SV2A on the intracellular transport of APP.APP,β-site amyloid precursor protein cleaving enzyme 1(BACE1)expressions,and APP cleavage products levels were investigated to observe the effects of SV2A on APP amyloidogenic processing.Results APP localization was reduced in the TGN,early endosomes,late endosomes,and lysosomes,whereas it was increased in the recycling endosomes and cell membrane of SV2A-overexpressed neurons.Moreover,Arl5b(ADP-ribosylation factor 5b),a protein responsible for transporting APP from the TGN to early endosomes,was upregulated by SV2A.SV2A overexpression also decreased APP transport from the cell membrane to early endosomes by downregulating APP endocytosis.In addition,products of APP amyloid degradation,including sAPPβ,Aβ1-42,and Aβ1-40,were decreased in SV2A-overexpressed cells.Conclusion These results demonstrated that SV2A promotes APP transport from the TGN to early endosomes by upregulating Arl5b and promoting APP transport from early endosomes to recycling endosomes-cell membrane pathway,which slows APP amyloid degradation.展开更多
Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model,experimental autoimmune encephalomyelitis(EAE).This study investigates the...Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model,experimental autoimmune encephalomyelitis(EAE).This study investigates the role of high mobility group box 1(HMGB1)in oligodendrocyte precursor cells(OPCs)in modulating pathogenic T cells infiltrating the central nervous system through the blood-brain barrier(BBB)by using OPC-specific HMGB1 knockout(KO)mice.We found that HMGB1 released from OPCs promotes BBB disruption,subsequently allowing increased immune cell infiltration.The migration of CD4+T cells isolated from EAE-induced mice was enhanced when co-cultured with OPCs compared to oligodendrocytes(OLs).OPC-specific HMGB1 KO mice exhibited lower BBB permeability and reduced immune cell infiltration into the CNS,leading to less damage to the myelin sheath and mitigated EAE progression.CD4+T cell migration was also reduced when co-cultured with HMGB1 knock-out OPCs.Our findings reveal that HMGB1 secretion from OPCs is crucial for regulating immune cell infiltration and provides insights into the immunomodulatory function of OPCs in autoimmune diseases.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52374119,42477142 and 42277154)Natural Science Foundation of Jiangsu Province(No.BK20242059)+1 种基金the open fund of State Key Laboratory of Hydraulics and Mountain River Engineering(No.SKHL2306)the High-level Talent Introduction Project of Changzhou University(No.ZMF24020037)。
文摘Rockburst precursors are critical for disaster warning,yet the complexity of rockburst has hindered the identification of a unified precursor.Furthermore,the influence of loading rates(LRs)on acoustic emission(AE)precursors in different rock types remains poorly understood.This study investigates the AE characteristics and early warning times of rockburst in slate and mica-schist under four LRs(0.05,0.15,0.25,and 0.5 MPa/s)using true triaxial unloading tests.The micro-crack state of the samples was evaluated using entropy,while critical slowing down(CSD)theory was applied to interpret AE precursors.The results reveal that as the LR increases,the rockburst stress of both rocks initially rises and then declines,with mica-schist exhibiting more severe damage and a higher dominance of tensile cracks.Notably,identifying rockburst precursors in mica-schist proved more challenging compared to slate.Among the methods tested,AE amplitude variance outperformed entropy in precursor identification.Additionally,the rockburst early warning time was found to be negatively correlated with the LR,with mica-schist consistently showing shorter warning times than slate.The CSD-derived precursor,due to its enhanced sensitivity,is recommended for early warning systems.These findings provide new insights into the role of LRs in rockburst dynamics and offer practical guidance for improving precursor identification and disaster mitigation strategies.
文摘Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechanical properties of carbon fibers, and therefore affect the overall performance of pultruded composites. This study systematically investigated the influence of PAN precursor properties on the degree of graphitization, surface morphology and mechanical properties of carbon fibers by regulating the molecular weight distribution, stretching ratio and impurity content of PAN precursor, and analyzed the mechanism of action of carbon fiber properties on the interfacial bonding strength and tensile/ bending properties of composites in combination with the pultrusion process. The results showed that when the filament stretchability was increased to 4.5 times, the axial orientation of carbon fibers increased by 18% and the tensile strength reached 520 MPa;Filaments with impurity content below 0.3% increase carbon fiber yield by 5.2% and interlaminar shear strength of composites by 23%. This study provides a theoretical basis for raw material screening and process optimization of high-performance carbon fibers and their composites.
文摘The increasing sophistication of cyberattacks,coupled with the limitations of rule-based detection systems,underscores the urgent need for proactive and intelligent cybersecurity solutions.Traditional intrusion detection systems often struggle with detecting early-stage threats,particularly in dynamic environments such as IoT,SDNs,and cloud infrastructures.These systems are hindered by high false positive rates,poor adaptability to evolving threats,and reliance on large labeled datasets.To address these challenges,this paper introduces CyberGuard-X,an AI-driven framework designed to identify attack precursors—subtle indicators of malicious intent—before full-scale intrusions occur.CyberGuard-X integrates anomaly detection,time-series analysis,and multi-stage classification within a scalable architecture.The model leverages deep learning techniques such as autoencoders,LSTM networks,and Transformer layers,supported by semi-supervised learning to enhance detection of zero-day and rare threats.Extensive experiments on benchmark datasets(CICIDS2017,CSE-CIC-IDS2018,and UNSW-NB15)demonstrate strong results,including 96.1%accuracy,94.7%precision,and 95.3%recall,while achieving a zero-day detection rate of 84.5%.With an inference time of 12.8 ms and 34.5%latency reduction,the model supports real-time deployment in resource-constrained environments.CyberGuard-X not only surpasses baseline models like LSTM and Random Forest but also enhances proactive threat mitigation across diverse network settings.
基金Projects(51934007,12072363,52004268) supported by the National Natural Science Foundation of ChinaProject(22KJD440002) supported by the Natural Science Fund for Colleges and Universities in Jiangsu Province,China。
文摘This study investigates the instability characteristics of dynamic disasters resulting from disruption caused by extracting resources underground. Utilizing the split Hopkinson pressure bar (SHPB) system, the dynamic response mechanism of coal energy evolution is examined, and the energy instability criterion is established. The validity of the instability criterion is explored from the standpoint of damage progression. The results demonstrate that the energy conversion mechanism undergoes a fundamental alternation under impact disturbance. Moreover, the energy release rate as well as the energy dissipation rate undergo comparable changes across distinct levels of impact disturbance. The distinction between the energy release rate and the energy dissipation rate (DRD) increases as coal mass deformation grows. Prior to coal facing instability and failure, the DRD experienced an inflection point followed by a sharp decrease. In conjunction with the discussion on the damage evolution, the physical and mechanical significance of DRD remains clear, which can essentially describe the whole impact loading process. The phenomenon that the inflection point appears and DRD subsequently suddenly decreases can be employed as the energy criterion prior to the failure of instability. Furthermore, this paper provides significant reference for the prediction of dynamic instability of coal under dynamic disturbance.
基金supported by the Key Program of the National Natural Science Foundation of China(No.52032003)the Major Program of the National Natural Science Foundation of China(No.52293372)+2 种基金the National Natural Science Foundation of China(No.51972082)the National Natural Science Foundation of China(No.52102093)the National Natural Science Foundation of China(No.52172041)and the science foundation of national key laboratory of science and technology on advanced composites in special environments.
文摘The current generation of ultrahigh temperature ceramic precursors typically encounters obstacles in achieving high ceramic yields(<40 wt.%)due to the challenges in integrating significant amounts of boron,which hampers their conversion into boride-based ultrahigh temperature ceramics.To tackle these challenges,a serious of pioneering liquid multi-component hafnium-containing ceramic SiHfCB precursors(with different Hf/Si ratios)have been developed.These novel precursors are featured with stable molec-ular structure and high ceramic yield which were successfully created through a novel one-pot polymer-ization process.They present in liquid form and their structure is characterized by C-C bonds forming its main chain with branched chains of O-Si-O,Si-O-Hf,Si-O-B,and B-O-Hf which have untapped advantages including uniform component dispersion,and excellent fluidity.The ceramic yield of SiHfCB precursor with Hf/Si of 0.2 is remarkably up to 68.6 wt.%at 1500℃,and their Hf content exceeded 50 wt.%.Of particular interest,the pyrolyzed product HfB_(2)-SiC nanopowders derived from the SiHfCB precursor with Hf/Si of 0.2,consist of nanopowders in the 40-60 nm range with a density of 5.23 g cm^(−3).Remarkably,this material demonstrates exceptional performance in ultrahigh temperature oxygen-containing environ-ments at 2500℃,showing near-zero ablation with a linear ablation rate of just 2.5×10^(−4) mm s^(−1).Post-ablation analysis of the microstructure reveals that the formation of a lava-like HfO_(2) and HfO_(2)-SiO_(2) oxide layer effectively blocks oxygen penetration and provides excellent oxidation resistance.The inno-vative SiHfCB hafnium-containing ceramic precursor offers a groundbreaking solution for the preparation of lightweight ultrahigh-temperature ceramics.This development is poised to provide robust technical support for the use of ultrahigh temperature ceramics in non-ablative thermal protective systems,partic-ularly in the construction of hypersonic vehicles,where ultrahigh temperature resilience is crucial.
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT)(Nos.RS-2024–00351052 and RS-2024–00450561)。
文摘Metal composites produced through the liquid metal dealloying(LMD)process feature an advanced matrix-matrix composite structure,where two metallic materials form a continuous,three-dimensional interconnected network.This study investigates the effects of Ti Cu precursor compositions on dealloying behavior and microstructural evolution in liquid Mg,using Ti_(50)Cu_(50)and Ti_(30)Cu_(70)precursors.The initial microstructure of the precursor significantly influences dealloying kinetics and phase transitions.The single-phase Ti_(50)Cu_(50)precursor exhibits a faster initial dealloying rate due to its homogeneous structure,yet complete dealloying requires 90 min.In contrast,the dualphase Ti_(30)Cu_(70)precursor achieves complete dealloying in 30 min,demonstrating the impact of a higher Cu concentration on accelerating the process kinetics.Additionally,the study explores the coarsening behavior and hardness variations during the LMD process,along with the microstructural characteristics of Mg-Ti composites fabricated from these two precursors.The findings highlight the critical role of precursor composition in tailoring the microstructure and properties of Mg-Ti composites produced through the LMD process,demonstrating its potential for advanced composite material manufacturing.
基金funded by Project Better Plastics—Plastics in a Circular Economy—PPS4(Circularity by Alternative Feedstocks)Grant agreement ID:POCI-01-0247-FEDER-046091RR was funded by FCT through the PhD grant with reference UI/BD/154446/2022.
文摘The growing environmental awareness,the search for alternatives to fossil resources,and the goal of achieving a circular economy have all contributed to the increasing valorization of biowaste to produce bio-based polymers and other high-value products.Among the various biowaste materials,lignin has gained significant attention due to its high aromatic carbon content,low cost,and abundance.Lignin is predominantly sourced as a byproduct from the paper industry,available in large quantities from hardwood and softwood,with variations in chemical structure and susceptibility to hydrolysis.This study focuses on softwood lignin obtained through the LignoForce^(TM) technology,comparing the thermal and chemical characteristics,and stability,of a recently produced batch with that of a batch that has been stored for four years.Additionally,the development of lignin-based thermoplastic polymer mixtures using Polyethylene Terephthalate Glycol(PET-G)and a blend of Polycarbonate and Acrylonitrile-Butadiene-Styrene(PC/ABS)with high lignin content(50–60 wt%)is explored,as well as the production of filaments for carbon fiber production.For this purpose,following melt mixing,the lignin-based mixtures were spun into filaments,which were subsequently subjected to thermal stabilization in an oxidative atmosphere.The lignin phase was well distributed in the PET-Gmatrix and the twomaterials presented a good interface,which further improved after thermal treatment under an oxidative atmosphere.After thermal treatment an increase in tensile modulus,tensile strength,and elongation at break of approximately 160%,200%,and 100%,respectively,was observed,confirming the good interface established,and consistent with structural changes such as cross-linking.Conversely,the PC/ABS blend did not form a good interface with the lignin domains after melt mixing.Although the interactions improved after thermal treatment,the tensile strength and elongation at break decreased by approximately 30%,while themodulus increased by approximately 20%.Overall,the good processability of the lignin/polymer mixtures into filaments,and their physical,chemical,and mechanical characterization before and after thermal oxidation are good indicators of the potential as precursors for carbon fiber production.
基金supported by NIH grants NIH/NIA R01AG069401(to L.Q.)NIH/NHLBI U54HL165442(to K.T.)P30AR069619(to Penn Center for Musculoskeletal Disorders).
文摘Bone resorption by osteoclasts is a critical step in bone remodeling,a process important for maintaining bone homeostasis and repairing injured bone.We previously identified a bone marrow mesenchymal subpopulation,marrow adipogenic lineage precursors(MALPs),and showed that its production of RANKL stimulates bone resorption in young mice using Adipoq-Cre.To exclude developmental defects and to investigate the role of MALPs-derived RANKL in adult bone,we generated inducible reporter mice(Adipoq-CreER Tomato)and RANKL deficient mice(Adipoq-CreER RANKLflox/flox,iCKO).Single cell-RNA sequencing data analysis and lineage tracing revealed that Adipoq+cells contain not only MALPs but also some mesenchymal progenitors capable of osteogenic differentiation.In situ hybridization showed that RANKL mRNA is only detected in MALPs,but not in osteogenic cells.RANKL deficiency in MALPs induced at 3 months of age rapidly increased trabecular bone mass in long bones as well as vertebrae due to diminished bone resorption but had no effect on the cortical bone.Ovariectomy(OVX)induced trabecular bone loss at both sites.RANKL depletion either before OVX or at 6 weeks post OVX protected and restored trabecular bone mass.Furthermore,bone healing after drill-hole injury was delayed in iCKO mice.Together,our findings demonstrate that MALPs play a dominant role in controlling trabecular bone resorption and that RANKL from MALPs is essential for trabecular bone turnover in adult bone homeostasis,postmenopausal bone loss,and injury repair.
基金supported by the National Natural Science Foundation of China(Nos.42371094,41907253)partially supported by the Interdisciplinary Cultivation Program of Xidian University(No.21103240005)the Postdoctoral Fellowship Program of CPSF(No.GZB20240589)。
文摘INTRODUCTION.On May 1st,2024,around 2:10 a.m.,a catastrophic collapse occurred along the Meilong Expressway near Meizhou City,Guangdong Province,China,at coordinates 24°29′24″N and 116°40′25″E.This collapse resulted in a pavement failure of approximately 17.9 m in length and covering an area of about 184.3 m^(2)(Chinanews,2024).
基金supported by the National Natural Science Foundation of China(No.52202090)the Fundamental Research Funds for the Central Universities(No.2082019014).
文摘Thorium dioxide(ThO_(2))fibers exhibit exceptional structural stability,low density and superior flexibility,coupled with a remarkably high melting point,positioning them as promising candidates for thermal protection applications.Additionally,their commendable secondary processing characteristics enable the development of diverse composite materials when integrated with other materials,significantly broadening the potential utilization of ThO_(2)materials and thorium resources in industrial fields.In this work,the ThO_(2)fiber was fabricated by the sol-gel precursor method,and the precursor with good spinnability and excellent stability was synthesized for the first time.The ThO_(2)fiber with a mean diameter of 868 nm is both highly flexible and strong(max.tensile strength 2.21 MPa),capable of bending freely across a wide temperature range from-196℃(in liquid nitrogen)to 1200℃.Meanwhile,it exhibits excellent temperature stability and heat insulation properties.The ThO_(2)nanofiber membranes with layered structure have low density(32-37 mg·cm^(-3)),low thermal conductivity(27.3-30.1 mW·m^(-1)·K^(-1)@25℃).The ThO_(2)nanofiber membranes with 15 mm thickness can reduce the temperature from 1200 to 282℃and maintain a high aspect ratio and bendability after 1200℃@90 min.The results show that the ThO_(2)fiber can be used as a new kind of high-temperature resistant material.
基金supported by grants from the State Key Program of the National Natural Science Foundation of China(grant number 82030064)Beijing Hospital Authority Youth Program(grant number QML20230812)+2 种基金Research and Development Foundation of Capital Medical University(grant number PYZ23052)National Natural Science Youth Cultivation Project of Xuanwu Hospital,Capital Medical University(grant number QNPY202317)Capital Medical University Research and Cultivation Fund(grant number PYZ23049).
文摘Objective To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A(SV2A)influences the distribution of amyloid precursor protein(APP)in the trans-Golgi network(TGN),endolysosomal system,and cell membranes and to reveal the effects of SV2A on APP amyloid degradation.Methods Colocalization analysis of APP with specific tagged proteins in the TGN,ensolysosomal system,and cell membrane was performed to explore the effects of SV2A on the intracellular transport of APP.APP,β-site amyloid precursor protein cleaving enzyme 1(BACE1)expressions,and APP cleavage products levels were investigated to observe the effects of SV2A on APP amyloidogenic processing.Results APP localization was reduced in the TGN,early endosomes,late endosomes,and lysosomes,whereas it was increased in the recycling endosomes and cell membrane of SV2A-overexpressed neurons.Moreover,Arl5b(ADP-ribosylation factor 5b),a protein responsible for transporting APP from the TGN to early endosomes,was upregulated by SV2A.SV2A overexpression also decreased APP transport from the cell membrane to early endosomes by downregulating APP endocytosis.In addition,products of APP amyloid degradation,including sAPPβ,Aβ1-42,and Aβ1-40,were decreased in SV2A-overexpressed cells.Conclusion These results demonstrated that SV2A promotes APP transport from the TGN to early endosomes by upregulating Arl5b and promoting APP transport from early endosomes to recycling endosomes-cell membrane pathway,which slows APP amyloid degradation.
基金supported by the National Research Foundation of Korea(NRF)funded by the government of the Republic of Korea[2023R1A2C1004955]the Technology Innovation Program funded by the Ministry of Trade,Industry&Energy(Korea)(20009707)+1 种基金the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1A6A3A01099056)the Korea Institute for Advancement of Technology funded by the Ministry of Trade,Industry and Energy(P0025489).
文摘Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model,experimental autoimmune encephalomyelitis(EAE).This study investigates the role of high mobility group box 1(HMGB1)in oligodendrocyte precursor cells(OPCs)in modulating pathogenic T cells infiltrating the central nervous system through the blood-brain barrier(BBB)by using OPC-specific HMGB1 knockout(KO)mice.We found that HMGB1 released from OPCs promotes BBB disruption,subsequently allowing increased immune cell infiltration.The migration of CD4+T cells isolated from EAE-induced mice was enhanced when co-cultured with OPCs compared to oligodendrocytes(OLs).OPC-specific HMGB1 KO mice exhibited lower BBB permeability and reduced immune cell infiltration into the CNS,leading to less damage to the myelin sheath and mitigated EAE progression.CD4+T cell migration was also reduced when co-cultured with HMGB1 knock-out OPCs.Our findings reveal that HMGB1 secretion from OPCs is crucial for regulating immune cell infiltration and provides insights into the immunomodulatory function of OPCs in autoimmune diseases.
