The objective of this work is to develop a novel methodology for determining real resistivity of conductive asphalt concrete based on two-electrode method.Due to an influence of contact resistance,the measured resisti...The objective of this work is to develop a novel methodology for determining real resistivity of conductive asphalt concrete based on two-electrode method.Due to an influence of contact resistance,the measured resistivity is always not equal to the real resistivity.To determine the real resistivity,a linear relationship of the measured resistivity,contact resistance and the real resistivity was established.Then experiments for six specimens with varying graphite contents were designed and performed to validate the formulation.Results of experiments demonstrate that the slope of the line represents contact resistance,and the intercept indicates the real resistivity.The effects of graphite content on contact resistance and real resistivity are also revealed.Finally,results show that the influence of contact resistance on accuracy of resisitvity measurement becomes more serious if graphite content is beyond 3%.Hence,it is the time to choose this novel methodology to determine the real resistivity of asphalt concrete by taking account of contact resistance.展开更多
The improvement of question soils with cement shows great technical, economic and environmental advantages. And interest in introducing electrical resistivity measurement to assess the quality of cement treated soils ...The improvement of question soils with cement shows great technical, economic and environmental advantages. And interest in introducing electrical resistivity measurement to assess the quality of cement treated soils has increased markedly recently due to its economical, non-destructive, and relatively non-invasive advantages. This work aims to quantify the effect of cement content （aw）, porosity （nt）, and curing time（T） on the electrical resistivity （p） and unconfined compression strength （UCS） of cement treated soil. A series of electrical resistivity tests and UCS tests of cement treated soil specimen after various curing periods were carried out. A modified Archie empirical law was proposed taking into account the effect of cement content and curing period on the electrical resistivity of cement treated soil. The results show that nt/（aw·T） and nt/（aw·T^1/2） ratio are appropriate parameters to assess electrical resistivity and UCS of cement treated soil, respectively. Finally, the relationship between UCS and electrical resistivity was also established.展开更多
The stability of cemented backfill mass is important to keep miners and equipment safe in underground backfill miming.The stress-strain behavior, resistivity and thermal infrared(TIR) characteristics of backfill mass ...The stability of cemented backfill mass is important to keep miners and equipment safe in underground backfill miming.The stress-strain behavior, resistivity and thermal infrared(TIR) characteristics of backfill mass under uniaxial compression were investigated. The monitoring system consisted of a TIR observation system, a stress-strain monitoring system and a resistivity measurement system. Precursory information for impending failure of cemented backfill mass was collected, including TIR, strain and resistivity precursors. The sensitivity and difference of different monitoring information to the same failure event were compared.The results show that the time-space evolution process of the resistivity and TIR is basically the same as the whole process from compression deformation to failure of backfill mass, and the time variation of resistivity and TIR is obviously characterized by stage.The resistivity precursor turns out earlier than the TIR and the strain. The resistivity relation with loading compression is anti-symmetry, decreasing as the compression stress increases before the peak strength of backfill mass. However, when the backfill mass enters into the phase of failure, the resistivity starts to increase as the stress increases. The change of the resistivity growth direction can be regarded as the resistivity-caution-point for the failure of backfill mass under uniaxial compression. It is also indicated that the TIR information mainly represents the surface temperature evolution in the process of compression before the backfill enters into the plastic-yield state. It can be a valuable tool to obtain the precursors for failure of cemented backfill mass for backfill mines.展开更多
Nonlinear resistivity inversion requires efficient artificial neural network(ANN)model for better inversion results.An evolutionary BP neural network(BPNN)approach based on differential evolution(DE)algorithm was pres...Nonlinear resistivity inversion requires efficient artificial neural network(ANN)model for better inversion results.An evolutionary BP neural network(BPNN)approach based on differential evolution(DE)algorithm was presented,which was able to improve global search ability for resistivity tomography 2-D nonlinear inversion.In the proposed method,Tent equation was applied to obtain automatic parameter settings in DE and the restricted parameter Fcrit was used to enhance the ability of converging to global optimum.An implementation of proposed DE-BPNN was given,the network had one hidden layer with 52 nodes and it was trained on 36 datasets and tested on another 4 synthetic datasets.Two abnormity models were used to verify the feasibility and effectiveness of the proposed method,the results show that the proposed DE-BP algorithm has better performance than BP,conventional DE-BP and other chaotic DE-BP methods in stability and accuracy,and higher imaging quality than least square inversion.展开更多
The electrical resistivity of TiB2/C cathode composite coating at different temperatures was measured with the electrical conductivity test device; the effects of TiB2 content and kinds of carbonaceous fillers as well...The electrical resistivity of TiB2/C cathode composite coating at different temperatures was measured with the electrical conductivity test device; the effects of TiB2 content and kinds of carbonaceous fillers as well as their mean particle size on their electrical resistivities were investigated. The results show that electrical resistivity of the coating decreases with the increase of TiB2 content and the decrease of its mean particle size. When the mass fraction of TiB2 increases from 30% to 60%, the electrical resistivity of the coating at room temperature decreases from 31.2μΩ·m to 23.8μΩ·m. The electrical resistivity of the coating at 960℃ lowers from 76.1μΩ· m to 38.4μΩ·m with the decrease of TiB2 mean particle size from 12μm to 1μm. The kinds of carbonaceous fillers have great influence on the electrical resistivity of TiB2/C composite coating at 960℃, when the graphite, petroleum coke and anthracite are used as fillers, the electrical resistivities of the coating are 20.3μΩ·m, 53.7μΩ·m and 87.2μΩ·m, respectively. For the coating with petroleum coke filler, its electrical resistivity decreases with the increase of the mean particle size of petroleum coke filler. The electrical resistivity at 960℃ decreases from 56.2μΩ·m to 48.2μΩ·m with the mean particle size of petroleum coke increasing from 44μm to 1200μm. However, too big carbonaceous particle size has adverse influence on the abrasion resistance of coating. Its proper mean particle size is 420μm.展开更多
In large loop transient electromagnetic method(TEM),the late time apparent resistivity formula cannot truly reflect the geoelectric model,thus it needs to define the all-time apparent resistivity with the position inf...In large loop transient electromagnetic method(TEM),the late time apparent resistivity formula cannot truly reflect the geoelectric model,thus it needs to define the all-time apparent resistivity with the position information of measuring point.Utilizing very fast simulated annealing(VFSA) to fit the theoretical electromagnetic force(EMF) and measured EMF could obtain the all-time apparent resistivity of the measuring points in rectangular transmitting loop.The selective cope of initial model of VFSA could be confirmed by taking the late time apparent resistivity of transient electromagnetic method as the prior information.For verifying the correctness,the all-time apparent resistivities of the geoelectric models were calculated by VFSA and dichotomy,respectively.The results indicate that the relative differences of apparent resistivities calculated by these two methods are within 3%.The change of measuring point position has little influence on the tracing pattern of all-time apparent resistivity.The first branch of the curve of all-time apparent resistivity is close to the resistivity of the first layer medium and the last branch is close to the resistivity of the last layer medium,which proves the correctness of the arithmetics proposed.展开更多
The strategies that minimize the overall solution time of multiple linear systems in 3D finite element method (FEM) modeling of direct current (DC) resistivity were discussed. A global stiff matrix is assembled and st...The strategies that minimize the overall solution time of multiple linear systems in 3D finite element method (FEM) modeling of direct current (DC) resistivity were discussed. A global stiff matrix is assembled and stored in two parts separately. One part is associated with the volume integral and the other is associated with the subsurface boundary integral. The equivalent multiple linear systems with closer right-hand sides than the original systems were constructed. A recycling Krylov subspace technique was employed to solve the multiple linear systems. The solution of the seed system was used as an initial guess for the subsequent systems. The results of two numerical experiments show that the improved algorithm reduces the iterations and CPU time by almost 50%, compared with the classical preconditioned conjugate gradient method.展开更多
To improve the global search ability and imaging quality of electrical resistivity imaging(ERI) inversion, a two-stage learning ICPSO algorithm of radial basis function neural network(RBFNN) based on information crite...To improve the global search ability and imaging quality of electrical resistivity imaging(ERI) inversion, a two-stage learning ICPSO algorithm of radial basis function neural network(RBFNN) based on information criterion(IC) and particle swarm optimization(PSO) is presented. In the proposed method, IC is applied to obtain the hidden layer structure by calculating the optimal IC value automatically and PSO algorithm is used to optimize the centers and widths of the radial basis functions in the hidden layer. Meanwhile, impacts of different information criteria to the inversion results are compared, and an implementation of the proposed ICPSO algorithm is given. The optimized neural network has one hidden layer with 261 nodes selected by AKAIKE's information criterion(AIC) and it is trained on 32 data sets and tested on another 8 synthetic data sets. Two complex synthetic examples are used to verify the feasibility and effectiveness of the proposed method with two learning stages. The results show that the proposed method has better performance and higher imaging quality than three-layer and four-layer back propagation neural networks(BPNNs) and traditional least square(LS) inversion.展开更多
DC Resistivity Tomography is a non-linear inversion problem. So far there are mainly two kinds of inversion methods, based on the finite-element method and alpha centers method. In this paper, the disadvantages of the...DC Resistivity Tomography is a non-linear inversion problem. So far there are mainly two kinds of inversion methods, based on the finite-element method and alpha centers method. In this paper, the disadvantages of these two kinds of methods were analysed,and a new method of forward modeling and inversion (Tomography) based on boundary integral equations was proposed. This scheme successfuly overcomes the difficulties of the two formarly methods. It isn’t necessary to use the linearization approximation and calculate the Jacobi matrix. Numerical modeling results given in this paper showed that the computation speed of our method is fast, and there is not any special requirement for initial model, and satisfying results of tomography can be obtained in the case of great contrast of conductivity. So it has wide applications.展开更多
Using resistivity as index and referring to the law about effect of slope to resistivity,the apparent resistivities of geophysical model concerned with unsteady rock type slope failure were calculated systematically b...Using resistivity as index and referring to the law about effect of slope to resistivity,the apparent resistivities of geophysical model concerned with unsteady rock type slope failure were calculated systematically by using the boundary integral equation method.After studying the feature of resistivity response of slope failure,the variety of resistivity during evolution of slope from steady to unsteady was found and the characteristics of resistivity response about slope failure was concluded.These make electrical exploring method for detecting the slip plane or structural plane of slope failure,evaluating the stability of the slope,and forecasting slope failure become true.展开更多
Abstract： PAN （Polyacrylonitrile）-based carbonaceous fibers were prepared at the heat treatment temperature （HTT） range of 650 to 900 ℃. The relationships among HTT, carbon content and volume resistivity of the ...Abstract： PAN （Polyacrylonitrile）-based carbonaceous fibers were prepared at the heat treatment temperature （HTT） range of 650 to 900 ℃. The relationships among HTT, carbon content and volume resistivity of the carbonaceous fibers were investigated. The carbonaceous fibers/PTFE （Polytetrafluoroethylene） antistatic coatings were prepared by the spraying technology and the effects of carbonaceous fibers and pigments on surface resistivity of the coatings were systematically discussed. Micrographs provide insight into the antistatic mechanism of the coating. The results show that carbon content of the carbonaceous fibers increases from 68.8% to 74.8% （mass fraction） and the volume resistivity decreases drastically from 1.94× 10^-3 to 8.27× 10 ^-2.cm. The surface resistivity of the antistatic coating is adjustable between 10^5 and 10^8Ω2 to fit the different antistatic materials. Static is dissipated by a conductive network of short fibers and the tunneling effect between the neighboring fibers and conductive pigments. Conductive pigments make the conductive network more perfect and improve the antistatic ability, but insulating pigments acting as barriers for the formation of conductive channel increases the surface resistivity of the coatings. The influence of pigments on the surface resistivity drops gradually with the decrease of the carbonaceous fibers volume resistivity.展开更多
Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization ...Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.展开更多
The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combi...The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.展开更多
The present work provides a facile and efficient method for producing ultrafine copper powders.Ultrafine copper powders were synthesized through a solvothermal method,utilizing ethanol both as a solvent and a reducing...The present work provides a facile and efficient method for producing ultrafine copper powders.Ultrafine copper powders were synthesized through a solvothermal method,utilizing ethanol both as a solvent and a reducing agent.Specifically,by exploiting the weak reducing property of ethanol,the copper precursor is first converted to copper oxide and then further reduced to cuprous oxide and pure copper.Such a method can effectively control the morphology and particle size of the copper powder,reduce particle aggregation,and enhance oxidation resistance.It is cost-effective and produces fewer toxic by-products.Spherical copper particles with an average particle size of about 180 nm were obtained.The initial oxidation temperature is approximately 150℃,and the resulting copper powders can be stored stably under ambient conditions for at least 5 months,demonstrating excellent oxidation resistance and thermal stability.展开更多
In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honey...In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honeycomb cells,was created by constructing arrangement matrices to achieve structural lightweight.The machine learning(ML)framework consisted of a neural network(NN)forward regression model for predicting impact resistance and a multi-objective optimization algorithm for generating high-performance designs.The surrogate of the local design space was initially realized by establishing the NN in the small sample dataset,and the active learning strategy was used to continuously extended the local optimal design until the model converged in the global space.The results indicated that the active learning strategy significantly improved the inference capability of the NN model in unknown design domains.By guiding the iteration direction of the optimization algorithm,lightweight designs with high impact resistance were identified.The energy absorption capacity of the optimal design reached 94.98%of the EARE honeycomb,while the initial peak stress and mass decreased by 28.85%and 19.91%,respectively.Furthermore,Shapley Additive Explanations(SHAP)for global explanation of the NN indicated a strong correlation between the arrangement mode of HCS and its impact resistance.By reducing the stiffness of the cells at the top boundary of the structure,the initial impact damage sustained by the structure can be significantly improved.Overall,this study proposed a general lightweight design method for array structures under impact loads,which is beneficial for the widespread application of honeycomb-based protective structures.展开更多
Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide...Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide fludioxonil is a key agent for FCR control.Previous studies indicated that resistance to fludioxonil in F.pseudograminearum is primarily associated with altered expression levels of the FpOS1 gene,which encodes a hybrid histidine kinase.However,the roles of mutations in other FpOS genes and the molecular interactions between FpOS proteins and fludioxonil remain elusive.To address these gaps,we generated 16 fludioxonil-resistant mutants with heritable resistance traits by in vitro selection of four sensitive F.pseudograminearum isolates.These mutants exhibited high resistance levels,with resistance factors(RF)ranging from 633.73 to 8617.07.Compared to their parental isolates,the resistant mutants showed significantly reduced mycelial growth rate,sporulation capacity,and pathogenicity.They were also more sensitive to ionic,osmotic,and oxidative stresses and displayed compromised cell wall and membrane integrity.Fludioxonil demonstrated no cross-resistance with tebuconazole or pydiflumetofen;however,it exhibited weak positive crossresistance to pyraclostrobin and moderate positive cross-resistance to iprodione.Fludioxonil treatment significantly promoted glycerol synthesis and inhibited deoxynivalenol(DON)production in parental isolates,whereas these regulatory effects were markedly attenuated in the resistant mutants.Mutation analysis identified mutation sites in FpOS1,FpOS4,and FpOS5 genes,with a lower mutation frequency in FpOS1 and no mutations detected in FpOS2.Molecular docking indicated that amino acid substitutions in FpOS4 and FpOS5 significantly reduced the binding affinity of fludioxonil to these target proteins.In conclusion,F.pseudograminearum poses a moderate risk of resistance to fludioxonil.Point mutations in FpOS4 and FpOS5 genes emerge as key molecular drivers of resistance,likely by diminishing the binding affinity between the fungicide and its proteins.This study clarifies the molecular basis of fludioxonil resistance in F.pseudograminearum and provides a scientific rationale for the judicious use of this fungicide in managing FCR.展开更多
Elastomers are extensively used in engineering,but their properties suffer when they are exposed to heat,ozone,UV radiation,and toxic chemicals.To improve their performance for specific industrial applications,they ar...Elastomers are extensively used in engineering,but their properties suffer when they are exposed to heat,ozone,UV radiation,and toxic chemicals.To improve their performance for specific industrial applications,they are often blended with other materials.We blended chloroprene rubber with brominated butyl rubber and reinforced it with Ketjenblack(KB)in concentrations up to 20%.KB has a porous and fluffy morphology and a high specific surface area of 1347 m^(2)/g.Tensile tests were conducted before and after exposure to UV,ozone,saline,petrol,and diesel environments,and their retention capacity was evaluated according to ASTM standards.Transmission electron microscopy revealed a uniform dispersion of KB filler.Tribological studies and barrier properties showed the best content of KB to be 10%because of its uniform dispersion.Thermal degradation kinetics were studied using Kissinger-Akahira-Sunose modelling to determine its activation energy.Dynamic mechanical analysis indicates a reduction of 5℃ in the glass transition for a 20%composite.These elastomeric blends can be considered cutting-edge materials with great potential for use in extremely harsh industrial applications.展开更多
Silica aerogel has broad applications in the field of high-temperature thermal insulation due to its low density,low thermal conductivity and high stability.However,its thermal insulation performance deteriorates sign...Silica aerogel has broad applications in the field of high-temperature thermal insulation due to its low density,low thermal conductivity and high stability.However,its thermal insulation performance deteriorates significantly at elevated temperatures exceeding 600℃,primarily due to the collapse of pore structure.Meanwhile,the shielding capacity of SiO_(2) aerogel to the infrared radiation at high temperature is rather low due to the intrinsic properties of SiO_(2).Herein,a strategy for improving the high-temperature stability and infrared shielding properties of SiO_(2) aerogel via Ca doping was explored.Calcium-doped silica aerogel(CSA)powders were prepared by Sol-Gel,hydrothermal,and ambient pressure drying(APD)techniques using water glass and anhydrous calcium chloride as precursors and trimethylchlorosilane as a hydrophobic modifier.The effects of Ca/Si molar ratio in the precursor and hydrothermal conditions(temperature and pH)on the crystalline properties,microscopic morphology and pore structure of CSAs were investigated.The results show that the Ca/Si molar ratio and hydrothermal treatment have significant effects on the microstructure and heat resistance of CSAs in the temperature range of 400-1000℃.The samples sintered at 1000℃have a high specific surface area of 100.1 m^(2)/g and a pore volume of 0.8705 cm^(3)/g,indicating that the CSA has good heat resistance.One-side insulation tests at temperatures up to 600℃show that the sample with a Ca/Si molar ratio of 1.0 has the best insulation performance,with a cold surface temperature of 450℃,which is 27℃lower than that of the pure silica aerogel.展开更多
It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,...It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,and FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbents were prepared by coupling fly ash-based Si-Al carriers.The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD,TG,XRF,BET and XPS,respectively.The effects of temperature,Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated.Results show that the SO_(2) promotes the arsenic removal of Fe_(2)O_(3),CeLaO and FeCeLaO.At 400℃,the arsenic removal efficiencies of the three oxides increase from 45.3%,72.5% and 81.3% without SO_(2) to 62.6%,80.5%and 91.0%,respectively.The SO_(2) inhibits the arsenic removal of La_(2)O_(2)CO_(3) and FeLaO,and the inhibition effect is pronounced at high temperatures.The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio.When the Si/Al ratio is increased to 9.74,the arsenic removal efficiency in the SO_(2) environment is 13.9% higher than that in the absence of SO_(2).Introducing FeCeLaO active components is beneficial for enhancing the SO_(2) poisoning resistance of Si-Al carriers.The strong sulfur resistance of the FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbent results from multiple factors:protective effects of Ce on Fe,La and Al;sulfation-induced generation of Ce^(3+)and surface-adsorbed oxygen;and strong surface acidity of SiO_(2).展开更多
Cancer stem cells(CSCs)represent a distinct subpopulation of cells characterized by self-renewal capacity,differentiation potential,and critical roles in driving tumor progression,therapeutic resistance,recurrence,and...Cancer stem cells(CSCs)represent a distinct subpopulation of cells characterized by self-renewal capacity,differentiation potential,and critical roles in driving tumor progression,therapeutic resistance,recurrence,and maintenance of the tumor microenvironment.Targeting CSCs has emerged as a pivotal direction in cancer research,offering novel strategies to overcome drug resistance and prevent metastasis and relapse.Lysosomes,traditionally recognized as central organelles for intracellular degradation and recycling,are indispensable for cellular homeostasis.Dysregulation of lysosomal function is intimately linked to various diseases,including cancer.In tumors,aberrant lysosomal activity can promote malignant progression through mechanisms such as altering metabolic pathways,enhancing lysosomal exocytosis,modulating drug resistance,and interfering with autophagy-lysosomal pathways.Recent studies have underscored the involvement of lysosomes in regulating CSC properties.This review synthesizes findings on lysosomal regulation of CSCs through the following aspects.(1)Lysosomes exert complex and critical bidirectional control over CSC stemness maintenance through three degradation pathways that are dependent on their degradative function.(i)The lysophagy pathway.This pathway exhibits dual roles.Activation can sustain CSC functions;for instance,in glioblastoma,hypoxia upregulates Gal-8 via the STAT3/HIF1αsignaling axis to induce autophagy,supporting stem cell survival.In head and neck squamous cell carcinoma,degradation of GSK3βactivates the Wnt pathway,enhancing stemness.Conversely,this pathway can suppress stemness by degrading stemness-related proteins such as BMI-1 and OCT4A,thereby impairing CSC selfrenewal capacity.(ii)Mitophagy pathway.In non-small cell lung cancer stem cells,mitophagy-related mechanisms,such as the accumulation of mitochondrial DNA(mtDNA)activating the TLR9-Notch1-AMPK signaling axis,have been shown to promote CSC proliferation.(iii)Autophagosome-dependent lysosomal degradation pathway.This pathway directly regulates stemness-related proteins in a bidirectional manner.Enhanced degradative function can promote CSC properties,exemplified by the degradation of NUMB to activate Notch signaling.Conversely,attenuated degradative function can also enhance stemness by stabilizing oncoproteins(e.g.,protecting Frizzled-1 from degradation to sustain Wnt signaling)or preventing the degradation of tumor suppressors(e.g.,inhibiting Notch degradation).(2)Constituent proteins of lysosomes,including membrane proteins and luminal acid hydrolases,participate in regulating CSC stemness.Regarding membrane proteins,LAMP2A facilitates chaperone-mediated autophagy to maintain stemness in glioblastoma and ovarian cancer.V-ATPase,by maintaining an acidic luminal environment,promotes proliferation and drug resistance in glioma stem cells.Among hydrolases,cathepsins B and L are highly expressed in pancreatic and ovarian cancers and correlate with poor prognosis.Furthermore,targeting lysosomes to induce lysosomal membrane permeabilization(LMP)triggers lysosome-mediated cell death,presenting a potential therapeutic strategy for eradicating CSCs.(3)The acidic luminal environment,single-membrane structure,and the presence of transmembrane transporters(e.g.,ABCA3)enable lysosomes to passively trap or actively uptake and sequester chemotherapeutic drugs.Subsequent drug extrusion via exocytosis confers drug resistance.In CSCs,this lysosome-mediated drug sequestration,often cooperating with autophagy,establishes multimodal drug resistance.Therefore,targeting lysosomal function represents a potential strategy to overcome therapy resistance.The central role of lysosomes in regulating CSC stemness and resistance positions them as highly promising therapeutic targets.Strategies aimed at disrupting lysosomal function to selectively eliminate CSCs include:inhibiting the lysosome-autophagy system using agents like IITZ or lovastatin;inducing lysosomal membrane permeabilization(LMP)with compounds such as hexamethylene amiloride to compromise membrane stability;and disrupting the acidic luminal environment using drugs like siramesine or the K/H transport compound 2.In conclusion,lysosomes critically regulate CSC stemness maintenance and drug resistance through degradative pathways,membrane protein functions,luminal hydrolase activities,and drug sequestration mechanisms.This redefines the lysosome from a traditional“waste disposal unit”to a“signal integration center”in CSCs.The duality and context-dependency of lysosomal function in CSCs offer novel insights into the heterogeneity observed across different tumors.Targeting lysosomal vulnerabilities—such as inducing LMP,disrupting acidity,or blocking autophagic flux—provides a strategy to bypass canonical CSC resistance mechanisms and directly trigger cell death.This establishes the lysosome as a key target to overcome CSC-mediated therapy resistance,paving the way for developing diverse candidate drugs and innovative combination therapies in oncology.展开更多
基金Project(51178348)supported by the National Natural Science Foundation of China
文摘The objective of this work is to develop a novel methodology for determining real resistivity of conductive asphalt concrete based on two-electrode method.Due to an influence of contact resistance,the measured resistivity is always not equal to the real resistivity.To determine the real resistivity,a linear relationship of the measured resistivity,contact resistance and the real resistivity was established.Then experiments for six specimens with varying graphite contents were designed and performed to validate the formulation.Results of experiments demonstrate that the slope of the line represents contact resistance,and the intercept indicates the real resistivity.The effects of graphite content on contact resistance and real resistivity are also revealed.Finally,results show that the influence of contact resistance on accuracy of resisitvity measurement becomes more serious if graphite content is beyond 3%.Hence,it is the time to choose this novel methodology to determine the real resistivity of asphalt concrete by taking account of contact resistance.
基金Project(BK2011618) supported by the Natural Science Foundation of Jiangsu Province, ChinaProject(51108288) supported by the National Natural Science Foundation of China
文摘The improvement of question soils with cement shows great technical, economic and environmental advantages. And interest in introducing electrical resistivity measurement to assess the quality of cement treated soils has increased markedly recently due to its economical, non-destructive, and relatively non-invasive advantages. This work aims to quantify the effect of cement content （aw）, porosity （nt）, and curing time（T） on the electrical resistivity （p） and unconfined compression strength （UCS） of cement treated soil. A series of electrical resistivity tests and UCS tests of cement treated soil specimen after various curing periods were carried out. A modified Archie empirical law was proposed taking into account the effect of cement content and curing period on the electrical resistivity of cement treated soil. The results show that nt/（aw·T） and nt/（aw·T^1/2） ratio are appropriate parameters to assess electrical resistivity and UCS of cement treated soil, respectively. Finally, the relationship between UCS and electrical resistivity was also established.
基金Projects(51504256,51004109)supported by the National Natural Science Foundation of ChinaProject(zdsys006)supported by State Key Laboratory of Safety and Health for Metal Mines,ChinaProject(2013BAB02B04)supported by the National Science and Technology Support Plan,China
文摘The stability of cemented backfill mass is important to keep miners and equipment safe in underground backfill miming.The stress-strain behavior, resistivity and thermal infrared(TIR) characteristics of backfill mass under uniaxial compression were investigated. The monitoring system consisted of a TIR observation system, a stress-strain monitoring system and a resistivity measurement system. Precursory information for impending failure of cemented backfill mass was collected, including TIR, strain and resistivity precursors. The sensitivity and difference of different monitoring information to the same failure event were compared.The results show that the time-space evolution process of the resistivity and TIR is basically the same as the whole process from compression deformation to failure of backfill mass, and the time variation of resistivity and TIR is obviously characterized by stage.The resistivity precursor turns out earlier than the TIR and the strain. The resistivity relation with loading compression is anti-symmetry, decreasing as the compression stress increases before the peak strength of backfill mass. However, when the backfill mass enters into the phase of failure, the resistivity starts to increase as the stress increases. The change of the resistivity growth direction can be regarded as the resistivity-caution-point for the failure of backfill mass under uniaxial compression. It is also indicated that the TIR information mainly represents the surface temperature evolution in the process of compression before the backfill enters into the plastic-yield state. It can be a valuable tool to obtain the precursors for failure of cemented backfill mass for backfill mines.
基金Project(20120162110015)supported by the Research Fund for the Doctoral Program of Higher Education,ChinaProject(41004053)supported by the National Natural Science Foundation of ChinaProject(12c0241)supported by Scientific Research Fund of Hunan Provincial Education Department,China
文摘Nonlinear resistivity inversion requires efficient artificial neural network(ANN)model for better inversion results.An evolutionary BP neural network(BPNN)approach based on differential evolution(DE)algorithm was presented,which was able to improve global search ability for resistivity tomography 2-D nonlinear inversion.In the proposed method,Tent equation was applied to obtain automatic parameter settings in DE and the restricted parameter Fcrit was used to enhance the ability of converging to global optimum.An implementation of proposed DE-BPNN was given,the network had one hidden layer with 52 nodes and it was trained on 36 datasets and tested on another 4 synthetic datasets.Two abnormity models were used to verify the feasibility and effectiveness of the proposed method,the results show that the proposed DE-BP algorithm has better performance than BP,conventional DE-BP and other chaotic DE-BP methods in stability and accuracy,and higher imaging quality than least square inversion.
基金Project(2005CB623703) supported by the State Key Fundamental Research and Development Programof China project(5JJ30103) supported by the Natural Science Foundation of Hunan Province
文摘The electrical resistivity of TiB2/C cathode composite coating at different temperatures was measured with the electrical conductivity test device; the effects of TiB2 content and kinds of carbonaceous fillers as well as their mean particle size on their electrical resistivities were investigated. The results show that electrical resistivity of the coating decreases with the increase of TiB2 content and the decrease of its mean particle size. When the mass fraction of TiB2 increases from 30% to 60%, the electrical resistivity of the coating at room temperature decreases from 31.2μΩ·m to 23.8μΩ·m. The electrical resistivity of the coating at 960℃ lowers from 76.1μΩ· m to 38.4μΩ·m with the decrease of TiB2 mean particle size from 12μm to 1μm. The kinds of carbonaceous fillers have great influence on the electrical resistivity of TiB2/C composite coating at 960℃, when the graphite, petroleum coke and anthracite are used as fillers, the electrical resistivities of the coating are 20.3μΩ·m, 53.7μΩ·m and 87.2μΩ·m, respectively. For the coating with petroleum coke filler, its electrical resistivity decreases with the increase of the mean particle size of petroleum coke filler. The electrical resistivity at 960℃ decreases from 56.2μΩ·m to 48.2μΩ·m with the mean particle size of petroleum coke increasing from 44μm to 1200μm. However, too big carbonaceous particle size has adverse influence on the abrasion resistance of coating. Its proper mean particle size is 420μm.
基金Projects(40804027,41074085) supported by the National Natural Science Foundation of ChinaProject(09JJ3048) supported by the Natural Science Foundation of Hunan Province,ChinaProject(200805331082) supported by the Research Fund for the Doctoral Program of Higher Education,China
文摘In large loop transient electromagnetic method(TEM),the late time apparent resistivity formula cannot truly reflect the geoelectric model,thus it needs to define the all-time apparent resistivity with the position information of measuring point.Utilizing very fast simulated annealing(VFSA) to fit the theoretical electromagnetic force(EMF) and measured EMF could obtain the all-time apparent resistivity of the measuring points in rectangular transmitting loop.The selective cope of initial model of VFSA could be confirmed by taking the late time apparent resistivity of transient electromagnetic method as the prior information.For verifying the correctness,the all-time apparent resistivities of the geoelectric models were calculated by VFSA and dichotomy,respectively.The results indicate that the relative differences of apparent resistivities calculated by these two methods are within 3%.The change of measuring point position has little influence on the tracing pattern of all-time apparent resistivity.The first branch of the curve of all-time apparent resistivity is close to the resistivity of the first layer medium and the last branch is close to the resistivity of the last layer medium,which proves the correctness of the arithmetics proposed.
基金Projects(40974077,41164004)supported by the National Natural Science Foundation of ChinaProject(2007AA06Z134)supported by the National High Technology Research and Development Program of China+2 种基金Projects(2011GXNSFA018003,0832263)supported by the Natural Science Foundation of Guangxi Province,ChinaProject supported by Program for Excellent Talents in Guangxi Higher Education Institution,ChinaProject supported by the Foundation of Guilin University of Technology,China
文摘The strategies that minimize the overall solution time of multiple linear systems in 3D finite element method (FEM) modeling of direct current (DC) resistivity were discussed. A global stiff matrix is assembled and stored in two parts separately. One part is associated with the volume integral and the other is associated with the subsurface boundary integral. The equivalent multiple linear systems with closer right-hand sides than the original systems were constructed. A recycling Krylov subspace technique was employed to solve the multiple linear systems. The solution of the seed system was used as an initial guess for the subsequent systems. The results of two numerical experiments show that the improved algorithm reduces the iterations and CPU time by almost 50%, compared with the classical preconditioned conjugate gradient method.
基金Project(41374118)supported by the National Natural Science Foundation,ChinaProject(20120162110015)supported by Research Fund for the Doctoral Program of Higher Education,China+3 种基金Project(2015M580700)supported by the China Postdoctoral Science Foundation,ChinaProject(2016JJ3086)supported by the Hunan Provincial Natural Science Foundation,ChinaProject(2015JC3067)supported by the Hunan Provincial Science and Technology Program,ChinaProject(15B138)supported by the Scientific Research Fund of Hunan Provincial Education Department,China
文摘To improve the global search ability and imaging quality of electrical resistivity imaging(ERI) inversion, a two-stage learning ICPSO algorithm of radial basis function neural network(RBFNN) based on information criterion(IC) and particle swarm optimization(PSO) is presented. In the proposed method, IC is applied to obtain the hidden layer structure by calculating the optimal IC value automatically and PSO algorithm is used to optimize the centers and widths of the radial basis functions in the hidden layer. Meanwhile, impacts of different information criteria to the inversion results are compared, and an implementation of the proposed ICPSO algorithm is given. The optimized neural network has one hidden layer with 261 nodes selected by AKAIKE's information criterion(AIC) and it is trained on 32 data sets and tested on another 8 synthetic data sets. Two complex synthetic examples are used to verify the feasibility and effectiveness of the proposed method with two learning stages. The results show that the proposed method has better performance and higher imaging quality than three-layer and four-layer back propagation neural networks(BPNNs) and traditional least square(LS) inversion.
文摘DC Resistivity Tomography is a non-linear inversion problem. So far there are mainly two kinds of inversion methods, based on the finite-element method and alpha centers method. In this paper, the disadvantages of these two kinds of methods were analysed,and a new method of forward modeling and inversion (Tomography) based on boundary integral equations was proposed. This scheme successfuly overcomes the difficulties of the two formarly methods. It isn’t necessary to use the linearization approximation and calculate the Jacobi matrix. Numerical modeling results given in this paper showed that the computation speed of our method is fast, and there is not any special requirement for initial model, and satisfying results of tomography can be obtained in the case of great contrast of conductivity. So it has wide applications.
基金Project(07JJ6072) supported by the Natural Science Foundation of Hunan Province,China
文摘Using resistivity as index and referring to the law about effect of slope to resistivity,the apparent resistivities of geophysical model concerned with unsteady rock type slope failure were calculated systematically by using the boundary integral equation method.After studying the feature of resistivity response of slope failure,the variety of resistivity during evolution of slope from steady to unsteady was found and the characteristics of resistivity response about slope failure was concluded.These make electrical exploring method for detecting the slip plane or structural plane of slope failure,evaluating the stability of the slope,and forecasting slope failure become true.
基金Project(2011CB605601)supported by the National Basic Research Program(973 Program)of ChinaProject(50902088)supported by the National Natural Science Foundation of China+1 种基金Project(ZR2011EMM002)supported by the Natural Science Foundation in Shandong Province,ChinaProject(2009AA035301)supported by the National High Technology Research and Development Program(863 Program)of China
文摘Abstract： PAN （Polyacrylonitrile）-based carbonaceous fibers were prepared at the heat treatment temperature （HTT） range of 650 to 900 ℃. The relationships among HTT, carbon content and volume resistivity of the carbonaceous fibers were investigated. The carbonaceous fibers/PTFE （Polytetrafluoroethylene） antistatic coatings were prepared by the spraying technology and the effects of carbonaceous fibers and pigments on surface resistivity of the coatings were systematically discussed. Micrographs provide insight into the antistatic mechanism of the coating. The results show that carbon content of the carbonaceous fibers increases from 68.8% to 74.8% （mass fraction） and the volume resistivity decreases drastically from 1.94× 10^-3 to 8.27× 10 ^-2.cm. The surface resistivity of the antistatic coating is adjustable between 10^5 and 10^8Ω2 to fit the different antistatic materials. Static is dissipated by a conductive network of short fibers and the tunneling effect between the neighboring fibers and conductive pigments. Conductive pigments make the conductive network more perfect and improve the antistatic ability, but insulating pigments acting as barriers for the formation of conductive channel increases the surface resistivity of the coatings. The influence of pigments on the surface resistivity drops gradually with the decrease of the carbonaceous fibers volume resistivity.
基金National Natural Science Foundation of China(Grant No.11872013)for supporting this project.
文摘Al/Ni reactive multilayer foil(RMF)possesses excellent comprehensive properties as a promising substitute for traditional Cu bridge.A theoretical resistivity model of Al/Ni RMF was developed to guide the optimization of EFIs.Al/Ni RMF with different bilayer thicknesses and bridge dimensions were prepared by MEMS technology and electrical explosion tests were carried out.According to physical and chemical reactions in bridge,the electrical explosion process was divided into 5 stages:heating of condensed bridge,vaporization and diffusion of Al layers,intermetallic combination reaction,intrinsic explosion,ionization of metal gases,which are obviously shown in measured voltage curve.Effects of interface and grain boundary scattering on the resistivity of film metal were considered.Focusing on variations of substance and state,the resistivity was developed as a function of temperature at each stage.Electrical explosion curves were calculated by this model at different bilayer thicknesses,bridge dimensions and capacitor voltages,which showed an excellent agreement with experimental ones.
基金Guangzhou Metro Scientific Research Project(No.JT204-100111-23001)Chongqing Municipal Special Project for Technological Innovation and Application Development(No.CSTB2022TIAD-KPX0101)Science and Technology Research and Development Program of China State Railway Group Co.,Ltd.(No.N2023G045)。
文摘The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.
文摘The present work provides a facile and efficient method for producing ultrafine copper powders.Ultrafine copper powders were synthesized through a solvothermal method,utilizing ethanol both as a solvent and a reducing agent.Specifically,by exploiting the weak reducing property of ethanol,the copper precursor is first converted to copper oxide and then further reduced to cuprous oxide and pure copper.Such a method can effectively control the morphology and particle size of the copper powder,reduce particle aggregation,and enhance oxidation resistance.It is cost-effective and produces fewer toxic by-products.Spherical copper particles with an average particle size of about 180 nm were obtained.The initial oxidation temperature is approximately 150℃,and the resulting copper powders can be stored stably under ambient conditions for at least 5 months,demonstrating excellent oxidation resistance and thermal stability.
基金the financial supports from National Key R&D Program for Young Scientists of China(Grant No.2022YFC3080900)National Natural Science Foundation of China(Grant No.52374181)+1 种基金BIT Research and Innovation Promoting Project(Grant No.2024YCXZ017)supported by Science and Technology Innovation Program of Beijing institute of technology under Grant No.2022CX01025。
文摘In this study,an inverse design framework was established to find lightweight honeycomb structures(HCSs)with high impact resistance.The hybrid HCS,composed of re-entrant(RE)and elliptical annular re-entrant(EARE)honeycomb cells,was created by constructing arrangement matrices to achieve structural lightweight.The machine learning(ML)framework consisted of a neural network(NN)forward regression model for predicting impact resistance and a multi-objective optimization algorithm for generating high-performance designs.The surrogate of the local design space was initially realized by establishing the NN in the small sample dataset,and the active learning strategy was used to continuously extended the local optimal design until the model converged in the global space.The results indicated that the active learning strategy significantly improved the inference capability of the NN model in unknown design domains.By guiding the iteration direction of the optimization algorithm,lightweight designs with high impact resistance were identified.The energy absorption capacity of the optimal design reached 94.98%of the EARE honeycomb,while the initial peak stress and mass decreased by 28.85%and 19.91%,respectively.Furthermore,Shapley Additive Explanations(SHAP)for global explanation of the NN indicated a strong correlation between the arrangement mode of HCS and its impact resistance.By reducing the stiffness of the cells at the top boundary of the structure,the initial impact damage sustained by the structure can be significantly improved.Overall,this study proposed a general lightweight design method for array structures under impact loads,which is beneficial for the widespread application of honeycomb-based protective structures.
基金Supported by Funding from the Henan Provincial Scientific and Technological Breakthrough Project(No.242102111113).
文摘Fusarium crown rot(FCR),predominantly caused by Fusarium pseudograminearum,has been listed as a Category Ⅱ disease in six provinces of China,posing a significant threat to wheat production.The phenylpyrrole fungicide fludioxonil is a key agent for FCR control.Previous studies indicated that resistance to fludioxonil in F.pseudograminearum is primarily associated with altered expression levels of the FpOS1 gene,which encodes a hybrid histidine kinase.However,the roles of mutations in other FpOS genes and the molecular interactions between FpOS proteins and fludioxonil remain elusive.To address these gaps,we generated 16 fludioxonil-resistant mutants with heritable resistance traits by in vitro selection of four sensitive F.pseudograminearum isolates.These mutants exhibited high resistance levels,with resistance factors(RF)ranging from 633.73 to 8617.07.Compared to their parental isolates,the resistant mutants showed significantly reduced mycelial growth rate,sporulation capacity,and pathogenicity.They were also more sensitive to ionic,osmotic,and oxidative stresses and displayed compromised cell wall and membrane integrity.Fludioxonil demonstrated no cross-resistance with tebuconazole or pydiflumetofen;however,it exhibited weak positive crossresistance to pyraclostrobin and moderate positive cross-resistance to iprodione.Fludioxonil treatment significantly promoted glycerol synthesis and inhibited deoxynivalenol(DON)production in parental isolates,whereas these regulatory effects were markedly attenuated in the resistant mutants.Mutation analysis identified mutation sites in FpOS1,FpOS4,and FpOS5 genes,with a lower mutation frequency in FpOS1 and no mutations detected in FpOS2.Molecular docking indicated that amino acid substitutions in FpOS4 and FpOS5 significantly reduced the binding affinity of fludioxonil to these target proteins.In conclusion,F.pseudograminearum poses a moderate risk of resistance to fludioxonil.Point mutations in FpOS4 and FpOS5 genes emerge as key molecular drivers of resistance,likely by diminishing the binding affinity between the fungicide and its proteins.This study clarifies the molecular basis of fludioxonil resistance in F.pseudograminearum and provides a scientific rationale for the judicious use of this fungicide in managing FCR.
文摘Elastomers are extensively used in engineering,but their properties suffer when they are exposed to heat,ozone,UV radiation,and toxic chemicals.To improve their performance for specific industrial applications,they are often blended with other materials.We blended chloroprene rubber with brominated butyl rubber and reinforced it with Ketjenblack(KB)in concentrations up to 20%.KB has a porous and fluffy morphology and a high specific surface area of 1347 m^(2)/g.Tensile tests were conducted before and after exposure to UV,ozone,saline,petrol,and diesel environments,and their retention capacity was evaluated according to ASTM standards.Transmission electron microscopy revealed a uniform dispersion of KB filler.Tribological studies and barrier properties showed the best content of KB to be 10%because of its uniform dispersion.Thermal degradation kinetics were studied using Kissinger-Akahira-Sunose modelling to determine its activation energy.Dynamic mechanical analysis indicates a reduction of 5℃ in the glass transition for a 20%composite.These elastomeric blends can be considered cutting-edge materials with great potential for use in extremely harsh industrial applications.
文摘Silica aerogel has broad applications in the field of high-temperature thermal insulation due to its low density,low thermal conductivity and high stability.However,its thermal insulation performance deteriorates significantly at elevated temperatures exceeding 600℃,primarily due to the collapse of pore structure.Meanwhile,the shielding capacity of SiO_(2) aerogel to the infrared radiation at high temperature is rather low due to the intrinsic properties of SiO_(2).Herein,a strategy for improving the high-temperature stability and infrared shielding properties of SiO_(2) aerogel via Ca doping was explored.Calcium-doped silica aerogel(CSA)powders were prepared by Sol-Gel,hydrothermal,and ambient pressure drying(APD)techniques using water glass and anhydrous calcium chloride as precursors and trimethylchlorosilane as a hydrophobic modifier.The effects of Ca/Si molar ratio in the precursor and hydrothermal conditions(temperature and pH)on the crystalline properties,microscopic morphology and pore structure of CSAs were investigated.The results show that the Ca/Si molar ratio and hydrothermal treatment have significant effects on the microstructure and heat resistance of CSAs in the temperature range of 400-1000℃.The samples sintered at 1000℃have a high specific surface area of 100.1 m^(2)/g and a pore volume of 0.8705 cm^(3)/g,indicating that the CSA has good heat resistance.One-side insulation tests at temperatures up to 600℃show that the sample with a Ca/Si molar ratio of 1.0 has the best insulation performance,with a cold surface temperature of 450℃,which is 27℃lower than that of the pure silica aerogel.
文摘It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,and FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbents were prepared by coupling fly ash-based Si-Al carriers.The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD,TG,XRF,BET and XPS,respectively.The effects of temperature,Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated.Results show that the SO_(2) promotes the arsenic removal of Fe_(2)O_(3),CeLaO and FeCeLaO.At 400℃,the arsenic removal efficiencies of the three oxides increase from 45.3%,72.5% and 81.3% without SO_(2) to 62.6%,80.5%and 91.0%,respectively.The SO_(2) inhibits the arsenic removal of La_(2)O_(2)CO_(3) and FeLaO,and the inhibition effect is pronounced at high temperatures.The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio.When the Si/Al ratio is increased to 9.74,the arsenic removal efficiency in the SO_(2) environment is 13.9% higher than that in the absence of SO_(2).Introducing FeCeLaO active components is beneficial for enhancing the SO_(2) poisoning resistance of Si-Al carriers.The strong sulfur resistance of the FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbent results from multiple factors:protective effects of Ce on Fe,La and Al;sulfation-induced generation of Ce^(3+)and surface-adsorbed oxygen;and strong surface acidity of SiO_(2).
文摘Cancer stem cells(CSCs)represent a distinct subpopulation of cells characterized by self-renewal capacity,differentiation potential,and critical roles in driving tumor progression,therapeutic resistance,recurrence,and maintenance of the tumor microenvironment.Targeting CSCs has emerged as a pivotal direction in cancer research,offering novel strategies to overcome drug resistance and prevent metastasis and relapse.Lysosomes,traditionally recognized as central organelles for intracellular degradation and recycling,are indispensable for cellular homeostasis.Dysregulation of lysosomal function is intimately linked to various diseases,including cancer.In tumors,aberrant lysosomal activity can promote malignant progression through mechanisms such as altering metabolic pathways,enhancing lysosomal exocytosis,modulating drug resistance,and interfering with autophagy-lysosomal pathways.Recent studies have underscored the involvement of lysosomes in regulating CSC properties.This review synthesizes findings on lysosomal regulation of CSCs through the following aspects.(1)Lysosomes exert complex and critical bidirectional control over CSC stemness maintenance through three degradation pathways that are dependent on their degradative function.(i)The lysophagy pathway.This pathway exhibits dual roles.Activation can sustain CSC functions;for instance,in glioblastoma,hypoxia upregulates Gal-8 via the STAT3/HIF1αsignaling axis to induce autophagy,supporting stem cell survival.In head and neck squamous cell carcinoma,degradation of GSK3βactivates the Wnt pathway,enhancing stemness.Conversely,this pathway can suppress stemness by degrading stemness-related proteins such as BMI-1 and OCT4A,thereby impairing CSC selfrenewal capacity.(ii)Mitophagy pathway.In non-small cell lung cancer stem cells,mitophagy-related mechanisms,such as the accumulation of mitochondrial DNA(mtDNA)activating the TLR9-Notch1-AMPK signaling axis,have been shown to promote CSC proliferation.(iii)Autophagosome-dependent lysosomal degradation pathway.This pathway directly regulates stemness-related proteins in a bidirectional manner.Enhanced degradative function can promote CSC properties,exemplified by the degradation of NUMB to activate Notch signaling.Conversely,attenuated degradative function can also enhance stemness by stabilizing oncoproteins(e.g.,protecting Frizzled-1 from degradation to sustain Wnt signaling)or preventing the degradation of tumor suppressors(e.g.,inhibiting Notch degradation).(2)Constituent proteins of lysosomes,including membrane proteins and luminal acid hydrolases,participate in regulating CSC stemness.Regarding membrane proteins,LAMP2A facilitates chaperone-mediated autophagy to maintain stemness in glioblastoma and ovarian cancer.V-ATPase,by maintaining an acidic luminal environment,promotes proliferation and drug resistance in glioma stem cells.Among hydrolases,cathepsins B and L are highly expressed in pancreatic and ovarian cancers and correlate with poor prognosis.Furthermore,targeting lysosomes to induce lysosomal membrane permeabilization(LMP)triggers lysosome-mediated cell death,presenting a potential therapeutic strategy for eradicating CSCs.(3)The acidic luminal environment,single-membrane structure,and the presence of transmembrane transporters(e.g.,ABCA3)enable lysosomes to passively trap or actively uptake and sequester chemotherapeutic drugs.Subsequent drug extrusion via exocytosis confers drug resistance.In CSCs,this lysosome-mediated drug sequestration,often cooperating with autophagy,establishes multimodal drug resistance.Therefore,targeting lysosomal function represents a potential strategy to overcome therapy resistance.The central role of lysosomes in regulating CSC stemness and resistance positions them as highly promising therapeutic targets.Strategies aimed at disrupting lysosomal function to selectively eliminate CSCs include:inhibiting the lysosome-autophagy system using agents like IITZ or lovastatin;inducing lysosomal membrane permeabilization(LMP)with compounds such as hexamethylene amiloride to compromise membrane stability;and disrupting the acidic luminal environment using drugs like siramesine or the K/H transport compound 2.In conclusion,lysosomes critically regulate CSC stemness maintenance and drug resistance through degradative pathways,membrane protein functions,luminal hydrolase activities,and drug sequestration mechanisms.This redefines the lysosome from a traditional“waste disposal unit”to a“signal integration center”in CSCs.The duality and context-dependency of lysosomal function in CSCs offer novel insights into the heterogeneity observed across different tumors.Targeting lysosomal vulnerabilities—such as inducing LMP,disrupting acidity,or blocking autophagic flux—provides a strategy to bypass canonical CSC resistance mechanisms and directly trigger cell death.This establishes the lysosome as a key target to overcome CSC-mediated therapy resistance,paving the way for developing diverse candidate drugs and innovative combination therapies in oncology.
