Acute respiratory distress syndrome(ARDS)is a severe and life-threatening manifestation of acute lung injury,characterized by widespread pulmonary inflammation and edema,ultimately resulting in acute respiratory failu...Acute respiratory distress syndrome(ARDS)is a severe and life-threatening manifestation of acute lung injury,characterized by widespread pulmonary inflammation and edema,ultimately resulting in acute respiratory failure.Despite advancements in mechanical ventilation and lung-protective strategies,targeted therapies aimed at modulating dysregulated inflammation and promoting tissue repair remain elusive.Extracellular vesicles(EVs),critical mediators of intercellular communication,have emerged as a promising research focus due to their dual regulatory roles in ARDS pathogenesis.Pro-inflammatory EVs,derived from pathogens or injury-stressed cells,exacerbate alveolar macrophage activation and increase endothelial permeability,thereby aggravating pulmonary damage.In contrast,anti-inflammatory EVs originating from mesenchymal stem cells facilitate alveolar barrier restoration and tissue repair by delivering reparative molecular cargo.This review systematically evaluates the dualistic functions of EVs in ARDS from three key perspectives:Molecular mechanisms,clinical translation,and technical challenges.We further discuss the complexities associated with EV heterogeneity,pathogen interactions,and standardization in EV production.Additionally,we propose future directions that integrate engineered EV modifications and multi-omics approaches to address current therapeutic limitations and enhance ARDS management.展开更多
The organic-rich shale of the Chang 7 member is the most important source rock in the Ordos basin.The sedimentary environment and the controlling factors of organic matter enrichment,however,are still in contention.In...The organic-rich shale of the Chang 7 member is the most important source rock in the Ordos basin.The sedimentary environment and the controlling factors of organic matter enrichment,however,are still in contention.In this investigation,the Yishicun outcrop,located on the south margin of the Ordos basin,has been considered for the study.X-ray diffraction,polarizing microscopy,field emission scanning electron microscopy and cathodoluminescence(CL)were used to investigate the petrological features of the organic-rich shale.The content of volcanic ash and the diameter of pyrite framboid pseudocrystals were measured to illustrate the relationship between oxygen level,ash content and the enrichment of organic matter.It has been found that the diameter of pyrite framboid pseudocrystals has a strong correlation with the total organic carbon,demonstrating that the redox status degree of the water column has a positive impact on the enrichment of organic matter.Additionally,with an increase in the ash content,the content of organic matter increased at first and then decreased,and reached a maximum when the ash content was about 6%,illustrating that the ash input has a double effect on the enrichment of organic matter.展开更多
The influence of extrusion temperature on microstructure and mechanical properties of heterogeneous Mg−1Gd/Mg−13Gd laminate prepared by accumulated extrusion bonding was investigated.The results reveal that the Mg−1Gd...The influence of extrusion temperature on microstructure and mechanical properties of heterogeneous Mg−1Gd/Mg−13Gd laminate prepared by accumulated extrusion bonding was investigated.The results reveal that the Mg−1Gd/Mg−13Gd laminate forms a significant difference in grain size between the successive layers when extruded at 330℃,and this difference gradually disappears as the extrusion temperature increases from 380 to 430℃.Besides,the growth rate of recrystallized grains in fine-grained layers is faster than that in coarse-grained layers.Moreover,the diffusion ability of Gd element increases with elevating extrusion temperatures,promoting the increase and coarsening of precipitates in fine-grained layers.Tensile tests indicate that the sample extruded at 380℃has a superior combination of strength and ductility.This is mainly attributed to the synergy of the heterogeneous texture between coarse and fine-grained layers,hetero-deformation induced strengthening and hardening.The fine-grained layers facilitate the activation of prismaticáañslips,while coarse-grained layers make it easier to active basaláañand pyramidalác+añslips,especially for the sample extruded at 380℃.The activation of pyramidalác+añslips contributes to coordinating further plastic deformation.展开更多
Coal and coalbed methane(CBM)coordinated exploitation is a key technology for the safe exploitation of both resources.However,existing studies lack the quantification and evaluation of the degree of coordination betwe...Coal and coalbed methane(CBM)coordinated exploitation is a key technology for the safe exploitation of both resources.However,existing studies lack the quantification and evaluation of the degree of coordination between coal mining and coalbed methane extraction.In this study,the concept of coal and coalbed methane coupling coordinated exploitation was proposed,and the corresponding evaluation model was established using the Bayesian principle.On this basis,the objective function of coal and coalbed methane coordinated exploitation deployment was established,and the optimal deployment was determined through a cuckoo search.The results show that clarifying the coupling coordinated level of coal and coalbed methane resource exploitation in coal mines is conducive to adjusting the deployment plan in advance.The case study results show that the evaluation and intelligent deployment method proposed in this paper can effectively evaluate the coupling coordinated level of coal and coalbed methane resource exploitation and intelligently optimize the deployment of coal mine operations.The optimization results demonstrate that the safe and efficient exploitation of coal and CBM resources is promoted,and coal mining and coalbed methane extraction processes show greater cooperation.The observations and findings of this study provide a critical reference for coal mine resource exploitation in the future.展开更多
Ulcerative colitis(UC)is a common progressive inflammatory disease whose incidence has increased rapidly in recent years,and can develop into colorectal cancer in severe cases.There are currently no adequate or effect...Ulcerative colitis(UC)is a common progressive inflammatory disease whose incidence has increased rapidly in recent years,and can develop into colorectal cancer in severe cases.There are currently no adequate or effective treatments for UC due to the fact that some patients have found suboptimal results after repeated administration,while others have experienced adverse effects.With the rapid development of nanotechnology,developing innovative colon-targeting platforms is essential to improving efficacy,reducing side effects,and improving patient compliance.In this review,we summarize the pathophysiological characteristics of UC and the most recent status of numerous nanodrug delivery systems based on different targeting mechanisms in treating UC.Oral,intravenous,and rectal drug delivery nanoparticles targeting the colon are discussed,which can provide ideas for the design of colon-targeting nanoparticles for the treatment of colon diseases,especially for the treatment of UC.Last but not least,we provide a glimpse into the future of colon-targeted delivery systems,as well as future advancements in the field.展开更多
The migration mode transition of cancer cell enhances its invasive capability and the drug resistance,where physical confinement of cell microenvironment has been revealed to induce the mesenchymal-amoeboid transition...The migration mode transition of cancer cell enhances its invasive capability and the drug resistance,where physical confinement of cell microenvironment has been revealed to induce the mesenchymal-amoeboid transition(MAT).However,most existing studies are performed in PDMS microchannels,of which the stiffness is much higher than that of most mammalian tissues.Therefore,the amoeboid migration transition observed in these studies is actually induced by the synergistic effect of matrix stiffness and confinement.Since the stiffness of cell microenvironment has been reported to influence the cell migration in 2D substrate,the decoupling of stiffness and confinement effects is thus in need for elucidating the underlying mechanism of MAT.However,it is technically challenging to construct microchannels with physiologically relevant stiffness and channel size,where existing microchannel platforms with physiological relevance stiffness are all with>10μm channel width.Such size is too wide to mimic the physical confinement that migrating cancer cells confront in vivo,and also larger than the width of PDMS channel,in which the MAT of cancer cell was observed.Therefore,an in vitro cell migration platform,which could mimic both stiffness and confinement of the native physical microenvironment during cancer metastasis,could profoundly contribute to researches on cancer cell migration and cellular mechanotransduction.In this paper,we overcome the limitations of engineering soft materials in microscale by combining the collagen-alginate hydrogel with photolithography.This enables us to improve the accuracy of molded microchannel,and thus successfully construct a 3D microchannel platform,which matches the stiffness and width ranges of native environmental confinement that migrating cancer cells confront in vivo.The stiffness(0.3~20 kPa),confinement(channel width:3.5~14μm)and the adhesion ligand density of the microchannel can be tuned independently.Interestingly,using this platform,we observed that the migration speed of cancer cell is influenced by the synergistic effect of channel stiffness and width,and the increasing stiffness reverses the effect of channel width on the migration speed of cancer cells.In addition,MAT has a strong correlation with the channel stiffness.These findings make us reconsider the widely accepted hypothesis:physical confinement can induce MAT.Actually,this transition can only occur in stiff confined microenvironment not in soft one.For soft microchannels,the compliance of the channel walls could cause little cell/nucleus deformation,and the MAT could not be induced.To further investigate the mechanism of MAT,we developed a computational model to simulate the effect of nucleus deformation on MAT.With the model,we found that deforming the cell nuclear by decreasing the nucleus stiffness will reduce the cellmigration speed.This implies that nuclear stiffness plays an important role in the regulation of cancer migration speed and thus MAT in microchannels.The effect of channel stiffness on MAT and migration speed as observed in our experiment could partially explain previous findings reported in the literature,where the increasing matrix stiffness of tumor microenvironment promotes cancer metastasis.Our observations thus highlight the critical role of cell nuclear deformation not only in MAT,but also in regulating cellular mechanotransduction and cell-ECM interactions.This developed platform is capable of mimicking the native physical microenvironment during metastasis,providing a powerful tool for high-throughput screening applications and investigating the interaction between cancer migration and biophysical microenvironment.展开更多
An image encryption algorithm is proposed in this paper based on a new four-dimensional hyperchaotic system,a neural mechanism,a Galois field and an improved Feistel block structure,which improves the efficiency and e...An image encryption algorithm is proposed in this paper based on a new four-dimensional hyperchaotic system,a neural mechanism,a Galois field and an improved Feistel block structure,which improves the efficiency and enhances the security of the encryption algorithm.Firstly,a four-dimensional hyperchaotic system with a large key space and chaotic dynamics performance is proposed and combined with a cloud model,in which a more complex and random sequence is constructed as the key stream,and the problem of chaotic periodicity is solved.Then,the key stream is combined with the neural mechanism,Galois field and improved Feistel block structure to scramble and diffuse the image encryption.Finally,the experimental results and security analysis show that the encryption algorithm has a good encryption effect and high encryption efficiency,is secure,and can meet the requirements of practical applications.展开更多
During drought,plant functions at multi-levels(i.e.,tissue,.cellular and molecular)are adjustable with the change of water condition,which is known as drought resistance.Various biological,chemical and physical mechan...During drought,plant functions at multi-levels(i.e.,tissue,.cellular and molecular)are adjustable with the change of water condition,which is known as drought resistance.Various biological,chemical and physical mechanisms have been found in plant drought resistance,among which the role of physical cues(especially mechanics)has attracted significantly increasing attention.Recent studies have shown that mechanics is one of the fundamental factors that control the responses and self-adaptation from tissue to molecular levels in plant when the external conditions changes.In the review,we examine how the factor of mechanics acts on the multi-level plant functions under drought stress,including water transport,tissue deformation,cell growth,cell movements,molecules interaction and signal pathway.展开更多
N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating conditions on the dea...N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating conditions on the deacidification performance were investigated.The deacidification performance of traditional organic solvents was also investigated for comparison.The results indicated that the naphthenic acid could be completely removed from the model oil with a small mass ratio of ionic liquid to oil.The extracted naphthenic acid was regenerated with a recovery of up to 92%.In addition,imidazolium carbonate ionic liquids could be successfully regenerated and recycled.The mechanism of interaction between imidazole ionic liquids and the naphthenic acid molecules were explained by Gauss calculation.展开更多
The AZ31 and AM60 alloys were used for dissimilar friction stir welding(FSW)in this study.The microstructure characteristics of the joint and its three-point bending performance were investigated.The electron backscat...The AZ31 and AM60 alloys were used for dissimilar friction stir welding(FSW)in this study.The microstructure characteristics of the joint and its three-point bending performance were investigated.The electron backscattered diffraction results showed that the grains in the nugget zone(NZ)were more uniform and refined to a certain extent after FSW,but the grain size of AM60 in the NZ was larger than that of AZ31.The texture was strong locally in the NZ and presented a symmetric distribution characteristic from the advancing side to the retreating side.There were special texture features in the joint,resulting in the occurrence of severe strain localization during the bending process compared with the base materials,which can be well explained by the calculated Schmid factor in terms of the assumed stress state for bending.The bending tests revealed that the joint presented good bending properties compared with AZ31 BM.The bending fracture morphologies suggested that the fracture tended to the NZ interface on the AZ31 side,which was mainly due to the higher SF for basal slip and dislocation concentration degree in the region,and the relatively lower bending strength of AZ31 metal.展开更多
OBJECTIVE Based on the methods of microdialysis,HPLC-MS/MS and gene chip tech.nology,the mechanism of Baicalin and Geniposide(BC/GP) against excitatory amino acid toxicity in ce.rebral ischemia was studied.This will p...OBJECTIVE Based on the methods of microdialysis,HPLC-MS/MS and gene chip tech.nology,the mechanism of Baicalin and Geniposide(BC/GP) against excitatory amino acid toxicity in ce.rebral ischemia was studied.This will provide guidance for the clinical application of BC/GP and the study of excitatory amino acid toxicity in cerebral ischemia.METHODS(1) Microdialysis technique and HPLC-MS/MS was performed to study the pharmacodynamics of BC/GP against cerebral ischemia.(1)18 SD rats with body weight of(280±20) g were randomly divided into control group,treatment groups with BC/CP at low dose,medium dose and high dose(equal to the dosage of crude drugs for 30 mg·kg^(-1),45 mg·kg^(-1) and 60 mg·kg^(-1) respectively).Rats in each group were given intragastric administration for seven days to establish cerebral ischemia model.Then,microdialysis probe was applied to collect cerebrospinal fluid from hippocampus before and after cerebral ischemia.(2) First,we established the HPLC-MS/MS method for measuring drugs and excitatory amino acids.Then we detected the microdi.alysis samples and observed their changes in animals.(2) The mechanism of BC/GP against excitatory toxicity of cerebral ischemia were observed at gene level by chip technique.(1) 16 SD rats with body weight of 240±20 g were randomly divided into sham group,model group,treatment group of BC(60 mg·kg^(-1)),treatment group of GP(60 mg·kg^(-1)) and treatment group of BC/GP(7:3)(60 mg·kg^(-1)).Rats in eachgroup were given intragastric administration for seven days to establish cerebral ischemia model.Then the rats were sacrificed,and the hippocampus were rapidly harvested and stored at-80℃ for further detection.(2) After the quality inspection of the hippocampal,the qualified samples were subjected to detect the levels of neurotransmitter receptor gene in the ischemic of rats by gene chip technology.Finally,the results were analyzed by the method of ΔΔCt.RESULTS(1) Only three compounds includ.ed GP,glutamic acid and aspartic acid were detected in microdialysis samples by HPLC-MS/MS.The concentration of GP increased and lasted for 120 min with a significant dose-dependent after cerebral ischemia.Compared with low dose group,the AUC(0-t),MRT(0-∞),Cmax and t1/2 z in high-dose group showed significant difference(P<0.01).Compared with the model group,the levels of glutamic acid and aspartic acid in the treatment groups decreased significantly,especially in the middle and high dose groups.(2)89 genes in the neurotransmitter receptor gene signaling pathway were detected by gene chip technol.ogy.There were 22 genes with |Fold Regulation| >1.5 in the model group,compared with the sham group.Five of the 22 genes showed statistically significant differences,including Grin2 c(2.9026),Chrna7(-1.5877),and Tacr2(-1.7695).Htr3 a(-1.8172) and Grm6(-2.3527).There were 5 genes with |Fold Regulation|>1.5 in the BC group,compared with the model group,Two of them exhibited statistically significant differences,including Brs3(1.797)and Grin2 c(-1.7979).There were 14 genes with |Fold Reg.ulation| >1.5 in the GP group,compared with the model group.Three of them displayed statistically significant differences,including Hcrtr2(-1.6584),Sctr(-3.8524) and Grin2 c(-4.8408).Compared with model group,the genes of |Fold Regulation| >1.5 in BC/GP(7:3) group are 5,and only one of them showed a significant differences.CONCLUSION(1) After administration of BC and GP,GP can cross the blood-brain barrier and reduce the release of excitatory amino acids in the hippocampus.(2) BC/GP can inhibit the interaction between excitatory amino acids and excitatory amino acid receptors and attenuate the toxicity of excitatory amino acids by down-regulating the expression of glutamic acid receptor Grin2 c gene.(3) BC/GP may exert their brain protection effect by reducing the release of excit.atory amino acids and inhibiting the expression of excitatory amino acid receptors.展开更多
We developed novel hybrid ligands to passivate Pb S colloidal quantum dots(CQDs),and two kinds of solar cells based on as-synthesized CQDs were fabricated to verify the passivation effects of the ligands.It was found ...We developed novel hybrid ligands to passivate Pb S colloidal quantum dots(CQDs),and two kinds of solar cells based on as-synthesized CQDs were fabricated to verify the passivation effects of the ligands.It was found that the ligands strongly affected the optical and electrical properties of CQDs,and the performances of solar cells were enhanced strongly.The optimized hybrid ligands,oleic amine/octyl-phosphine acid/Cd Cl2improved power conversion efficiency(PCE)to much higher of 3.72%for Schottky diode cell and 5.04%for p–n junction cell.These results may be beneficial to design passivation strategy for low-cost and high-performance CQDs solar cells.展开更多
Gallium arsenide(GaAs),a typical covalent semiconductor,is widely used in the electronic industry,owing to its superior electron transport properties.However,its brittle nature is a drawback that has so far significan...Gallium arsenide(GaAs),a typical covalent semiconductor,is widely used in the electronic industry,owing to its superior electron transport properties.However,its brittle nature is a drawback that has so far significantly limited its application.An exploration of the structural deformation modes of GaAs under large strain at the atomic level,and the formulation of strategies to enhance its mechanical properties is highly desirable.The stressstrain relations and deformation modes of single-crystal and nanotwinned GaAs under various loading conditions are systematically investigated,using first-principles calculations.Our results show that the ideal strengths of nanotwinned GaAs are 14% and 15% higher than that of single-crystal GaAs under pure and indentation shear strains,respectively,without producing a significantly negative effect in terms of its electronic performance.The enhancement in strength stems from the rearrangement of directional covalent bonds at the twin boundary.Our results offer a fundamental understanding of the mechanical properties of single crystal GaAs,and provide insights into the strengthening mechanism of nanotwinned GaAs,which could prove highly beneficial in terms of developing reliable electronic devices.展开更多
基金Supported by National Natural Science Foundation of China,No.82374400Heilongjiang Province“Double First-Class”New Round of Construction Disciplines Collaborative Innovation Achievements Construction Project,No.LJGXCG2022-097.
文摘Acute respiratory distress syndrome(ARDS)is a severe and life-threatening manifestation of acute lung injury,characterized by widespread pulmonary inflammation and edema,ultimately resulting in acute respiratory failure.Despite advancements in mechanical ventilation and lung-protective strategies,targeted therapies aimed at modulating dysregulated inflammation and promoting tissue repair remain elusive.Extracellular vesicles(EVs),critical mediators of intercellular communication,have emerged as a promising research focus due to their dual regulatory roles in ARDS pathogenesis.Pro-inflammatory EVs,derived from pathogens or injury-stressed cells,exacerbate alveolar macrophage activation and increase endothelial permeability,thereby aggravating pulmonary damage.In contrast,anti-inflammatory EVs originating from mesenchymal stem cells facilitate alveolar barrier restoration and tissue repair by delivering reparative molecular cargo.This review systematically evaluates the dualistic functions of EVs in ARDS from three key perspectives:Molecular mechanisms,clinical translation,and technical challenges.We further discuss the complexities associated with EV heterogeneity,pathogen interactions,and standardization in EV production.Additionally,we propose future directions that integrate engineered EV modifications and multi-omics approaches to address current therapeutic limitations and enhance ARDS management.
文摘The organic-rich shale of the Chang 7 member is the most important source rock in the Ordos basin.The sedimentary environment and the controlling factors of organic matter enrichment,however,are still in contention.In this investigation,the Yishicun outcrop,located on the south margin of the Ordos basin,has been considered for the study.X-ray diffraction,polarizing microscopy,field emission scanning electron microscopy and cathodoluminescence(CL)were used to investigate the petrological features of the organic-rich shale.The content of volcanic ash and the diameter of pyrite framboid pseudocrystals were measured to illustrate the relationship between oxygen level,ash content and the enrichment of organic matter.It has been found that the diameter of pyrite framboid pseudocrystals has a strong correlation with the total organic carbon,demonstrating that the redox status degree of the water column has a positive impact on the enrichment of organic matter.Additionally,with an increase in the ash content,the content of organic matter increased at first and then decreased,and reached a maximum when the ash content was about 6%,illustrating that the ash input has a double effect on the enrichment of organic matter.
基金financially supported by the National Natural Science Foundation of China(Nos.52071035,U1764253)。
文摘The influence of extrusion temperature on microstructure and mechanical properties of heterogeneous Mg−1Gd/Mg−13Gd laminate prepared by accumulated extrusion bonding was investigated.The results reveal that the Mg−1Gd/Mg−13Gd laminate forms a significant difference in grain size between the successive layers when extruded at 330℃,and this difference gradually disappears as the extrusion temperature increases from 380 to 430℃.Besides,the growth rate of recrystallized grains in fine-grained layers is faster than that in coarse-grained layers.Moreover,the diffusion ability of Gd element increases with elevating extrusion temperatures,promoting the increase and coarsening of precipitates in fine-grained layers.Tensile tests indicate that the sample extruded at 380℃has a superior combination of strength and ductility.This is mainly attributed to the synergy of the heterogeneous texture between coarse and fine-grained layers,hetero-deformation induced strengthening and hardening.The fine-grained layers facilitate the activation of prismaticáañslips,while coarse-grained layers make it easier to active basaláañand pyramidalác+añslips,especially for the sample extruded at 380℃.The activation of pyramidalác+añslips contributes to coordinating further plastic deformation.
基金supported by the Natural Science Foundation of Chongqing,China(No.cstc2020jcyj-msxmX0836)the Fundamental Research Funds for the Central Universities(No.2020CDJ-LHZZ-002)the National Natural Science Foundation of China(No.52074041).
文摘Coal and coalbed methane(CBM)coordinated exploitation is a key technology for the safe exploitation of both resources.However,existing studies lack the quantification and evaluation of the degree of coordination between coal mining and coalbed methane extraction.In this study,the concept of coal and coalbed methane coupling coordinated exploitation was proposed,and the corresponding evaluation model was established using the Bayesian principle.On this basis,the objective function of coal and coalbed methane coordinated exploitation deployment was established,and the optimal deployment was determined through a cuckoo search.The results show that clarifying the coupling coordinated level of coal and coalbed methane resource exploitation in coal mines is conducive to adjusting the deployment plan in advance.The case study results show that the evaluation and intelligent deployment method proposed in this paper can effectively evaluate the coupling coordinated level of coal and coalbed methane resource exploitation and intelligently optimize the deployment of coal mine operations.The optimization results demonstrate that the safe and efficient exploitation of coal and CBM resources is promoted,and coal mining and coalbed methane extraction processes show greater cooperation.The observations and findings of this study provide a critical reference for coal mine resource exploitation in the future.
基金financially supported by Beijing Nova Program(Nos.Z211100002121127 and 20220484219)Beijing Natural Science Foundation(No.L212059)+1 种基金Fundamental Research Funds for the Central Universities(No.3332021101)CAMS Innovation Fund for Medical Sciences(CIFMS,Nos.2021-I2M-1-026 and 2021-I2M-1-028).
文摘Ulcerative colitis(UC)is a common progressive inflammatory disease whose incidence has increased rapidly in recent years,and can develop into colorectal cancer in severe cases.There are currently no adequate or effective treatments for UC due to the fact that some patients have found suboptimal results after repeated administration,while others have experienced adverse effects.With the rapid development of nanotechnology,developing innovative colon-targeting platforms is essential to improving efficacy,reducing side effects,and improving patient compliance.In this review,we summarize the pathophysiological characteristics of UC and the most recent status of numerous nanodrug delivery systems based on different targeting mechanisms in treating UC.Oral,intravenous,and rectal drug delivery nanoparticles targeting the colon are discussed,which can provide ideas for the design of colon-targeting nanoparticles for the treatment of colon diseases,especially for the treatment of UC.Last but not least,we provide a glimpse into the future of colon-targeted delivery systems,as well as future advancements in the field.
基金financially supported by the National Natural Science Foundation of China ( 11532009, 11602191,21775117)the General Financial Grant from the China Postdoctoral Science Foundation ( 2016M592773)the High Level Returned Overseas Students Foundation ( [2018]642)
文摘The migration mode transition of cancer cell enhances its invasive capability and the drug resistance,where physical confinement of cell microenvironment has been revealed to induce the mesenchymal-amoeboid transition(MAT).However,most existing studies are performed in PDMS microchannels,of which the stiffness is much higher than that of most mammalian tissues.Therefore,the amoeboid migration transition observed in these studies is actually induced by the synergistic effect of matrix stiffness and confinement.Since the stiffness of cell microenvironment has been reported to influence the cell migration in 2D substrate,the decoupling of stiffness and confinement effects is thus in need for elucidating the underlying mechanism of MAT.However,it is technically challenging to construct microchannels with physiologically relevant stiffness and channel size,where existing microchannel platforms with physiological relevance stiffness are all with>10μm channel width.Such size is too wide to mimic the physical confinement that migrating cancer cells confront in vivo,and also larger than the width of PDMS channel,in which the MAT of cancer cell was observed.Therefore,an in vitro cell migration platform,which could mimic both stiffness and confinement of the native physical microenvironment during cancer metastasis,could profoundly contribute to researches on cancer cell migration and cellular mechanotransduction.In this paper,we overcome the limitations of engineering soft materials in microscale by combining the collagen-alginate hydrogel with photolithography.This enables us to improve the accuracy of molded microchannel,and thus successfully construct a 3D microchannel platform,which matches the stiffness and width ranges of native environmental confinement that migrating cancer cells confront in vivo.The stiffness(0.3~20 kPa),confinement(channel width:3.5~14μm)and the adhesion ligand density of the microchannel can be tuned independently.Interestingly,using this platform,we observed that the migration speed of cancer cell is influenced by the synergistic effect of channel stiffness and width,and the increasing stiffness reverses the effect of channel width on the migration speed of cancer cells.In addition,MAT has a strong correlation with the channel stiffness.These findings make us reconsider the widely accepted hypothesis:physical confinement can induce MAT.Actually,this transition can only occur in stiff confined microenvironment not in soft one.For soft microchannels,the compliance of the channel walls could cause little cell/nucleus deformation,and the MAT could not be induced.To further investigate the mechanism of MAT,we developed a computational model to simulate the effect of nucleus deformation on MAT.With the model,we found that deforming the cell nuclear by decreasing the nucleus stiffness will reduce the cellmigration speed.This implies that nuclear stiffness plays an important role in the regulation of cancer migration speed and thus MAT in microchannels.The effect of channel stiffness on MAT and migration speed as observed in our experiment could partially explain previous findings reported in the literature,where the increasing matrix stiffness of tumor microenvironment promotes cancer metastasis.Our observations thus highlight the critical role of cell nuclear deformation not only in MAT,but also in regulating cellular mechanotransduction and cell-ECM interactions.This developed platform is capable of mimicking the native physical microenvironment during metastasis,providing a powerful tool for high-throughput screening applications and investigating the interaction between cancer migration and biophysical microenvironment.
基金Project supported by the National Natural Science Foundation of China(Grant No.61973248)the Key Project of the Shaanxi Key Research and Development Program,China(Grant No.2018ZDXM-GY-089)。
文摘An image encryption algorithm is proposed in this paper based on a new four-dimensional hyperchaotic system,a neural mechanism,a Galois field and an improved Feistel block structure,which improves the efficiency and enhances the security of the encryption algorithm.Firstly,a four-dimensional hyperchaotic system with a large key space and chaotic dynamics performance is proposed and combined with a cloud model,in which a more complex and random sequence is constructed as the key stream,and the problem of chaotic periodicity is solved.Then,the key stream is combined with the neural mechanism,Galois field and improved Feistel block structure to scramble and diffuse the image encryption.Finally,the experimental results and security analysis show that the encryption algorithm has a good encryption effect and high encryption efficiency,is secure,and can meet the requirements of practical applications.
基金the National Natural Science Foundation of China(Grants 11532009,11972280,11972185,11902155,and 11902245)the Natural Science Foundation of Jiangsu Province(Grant BK20190382)+3 种基金the foundation of"Jiangsu Provincial Key Laboratory of Bionic Functional Materials"the Foundation for the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Open Fund of the State Key Laboratory of MechanicsControl of Mechanical Structures of China(Grants MCMS-I-0219K01 and MCMS-E-0219K02).
文摘During drought,plant functions at multi-levels(i.e.,tissue,.cellular and molecular)are adjustable with the change of water condition,which is known as drought resistance.Various biological,chemical and physical mechanisms have been found in plant drought resistance,among which the role of physical cues(especially mechanics)has attracted significantly increasing attention.Recent studies have shown that mechanics is one of the fundamental factors that control the responses and self-adaptation from tissue to molecular levels in plant when the external conditions changes.In the review,we examine how the factor of mechanics acts on the multi-level plant functions under drought stress,including water transport,tissue deformation,cell growth,cell movements,molecules interaction and signal pathway.
基金support of the National Natural Science Foundation of China(22078359,21276275).
文摘N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating conditions on the deacidification performance were investigated.The deacidification performance of traditional organic solvents was also investigated for comparison.The results indicated that the naphthenic acid could be completely removed from the model oil with a small mass ratio of ionic liquid to oil.The extracted naphthenic acid was regenerated with a recovery of up to 92%.In addition,imidazolium carbonate ionic liquids could be successfully regenerated and recycled.The mechanism of interaction between imidazole ionic liquids and the naphthenic acid molecules were explained by Gauss calculation.
基金financially supported by the National Natural Science Foundation of China(No.52071035,U1764253)。
文摘The AZ31 and AM60 alloys were used for dissimilar friction stir welding(FSW)in this study.The microstructure characteristics of the joint and its three-point bending performance were investigated.The electron backscattered diffraction results showed that the grains in the nugget zone(NZ)were more uniform and refined to a certain extent after FSW,but the grain size of AM60 in the NZ was larger than that of AZ31.The texture was strong locally in the NZ and presented a symmetric distribution characteristic from the advancing side to the retreating side.There were special texture features in the joint,resulting in the occurrence of severe strain localization during the bending process compared with the base materials,which can be well explained by the calculated Schmid factor in terms of the assumed stress state for bending.The bending tests revealed that the joint presented good bending properties compared with AZ31 BM.The bending fracture morphologies suggested that the fracture tended to the NZ interface on the AZ31 side,which was mainly due to the higher SF for basal slip and dislocation concentration degree in the region,and the relatively lower bending strength of AZ31 metal.
基金supported by National Natural Science Foundation of China(81473385) Shaanxi provincial Natural Science Foundation of China(2017JZ027) Shaanxi Provincial Administration of Traditional Chinese Medicine(13-ZY016)
文摘OBJECTIVE Based on the methods of microdialysis,HPLC-MS/MS and gene chip tech.nology,the mechanism of Baicalin and Geniposide(BC/GP) against excitatory amino acid toxicity in ce.rebral ischemia was studied.This will provide guidance for the clinical application of BC/GP and the study of excitatory amino acid toxicity in cerebral ischemia.METHODS(1) Microdialysis technique and HPLC-MS/MS was performed to study the pharmacodynamics of BC/GP against cerebral ischemia.(1)18 SD rats with body weight of(280±20) g were randomly divided into control group,treatment groups with BC/CP at low dose,medium dose and high dose(equal to the dosage of crude drugs for 30 mg·kg^(-1),45 mg·kg^(-1) and 60 mg·kg^(-1) respectively).Rats in each group were given intragastric administration for seven days to establish cerebral ischemia model.Then,microdialysis probe was applied to collect cerebrospinal fluid from hippocampus before and after cerebral ischemia.(2) First,we established the HPLC-MS/MS method for measuring drugs and excitatory amino acids.Then we detected the microdi.alysis samples and observed their changes in animals.(2) The mechanism of BC/GP against excitatory toxicity of cerebral ischemia were observed at gene level by chip technique.(1) 16 SD rats with body weight of 240±20 g were randomly divided into sham group,model group,treatment group of BC(60 mg·kg^(-1)),treatment group of GP(60 mg·kg^(-1)) and treatment group of BC/GP(7:3)(60 mg·kg^(-1)).Rats in eachgroup were given intragastric administration for seven days to establish cerebral ischemia model.Then the rats were sacrificed,and the hippocampus were rapidly harvested and stored at-80℃ for further detection.(2) After the quality inspection of the hippocampal,the qualified samples were subjected to detect the levels of neurotransmitter receptor gene in the ischemic of rats by gene chip technology.Finally,the results were analyzed by the method of ΔΔCt.RESULTS(1) Only three compounds includ.ed GP,glutamic acid and aspartic acid were detected in microdialysis samples by HPLC-MS/MS.The concentration of GP increased and lasted for 120 min with a significant dose-dependent after cerebral ischemia.Compared with low dose group,the AUC(0-t),MRT(0-∞),Cmax and t1/2 z in high-dose group showed significant difference(P<0.01).Compared with the model group,the levels of glutamic acid and aspartic acid in the treatment groups decreased significantly,especially in the middle and high dose groups.(2)89 genes in the neurotransmitter receptor gene signaling pathway were detected by gene chip technol.ogy.There were 22 genes with |Fold Regulation| >1.5 in the model group,compared with the sham group.Five of the 22 genes showed statistically significant differences,including Grin2 c(2.9026),Chrna7(-1.5877),and Tacr2(-1.7695).Htr3 a(-1.8172) and Grm6(-2.3527).There were 5 genes with |Fold Regulation|>1.5 in the BC group,compared with the model group,Two of them exhibited statistically significant differences,including Brs3(1.797)and Grin2 c(-1.7979).There were 14 genes with |Fold Reg.ulation| >1.5 in the GP group,compared with the model group.Three of them displayed statistically significant differences,including Hcrtr2(-1.6584),Sctr(-3.8524) and Grin2 c(-4.8408).Compared with model group,the genes of |Fold Regulation| >1.5 in BC/GP(7:3) group are 5,and only one of them showed a significant differences.CONCLUSION(1) After administration of BC and GP,GP can cross the blood-brain barrier and reduce the release of excitatory amino acids in the hippocampus.(2) BC/GP can inhibit the interaction between excitatory amino acids and excitatory amino acid receptors and attenuate the toxicity of excitatory amino acids by down-regulating the expression of glutamic acid receptor Grin2 c gene.(3) BC/GP may exert their brain protection effect by reducing the release of excit.atory amino acids and inhibiting the expression of excitatory amino acid receptors.
基金financial support of the National Natural Science Foundation of China(No.9133320661274062+2 种基金and11204106)National Science Foundation for Distinguished Young Scholars of China(Grant No.51225301)Guangdong Province Natural Science Fund(No.2014A030313257)
文摘We developed novel hybrid ligands to passivate Pb S colloidal quantum dots(CQDs),and two kinds of solar cells based on as-synthesized CQDs were fabricated to verify the passivation effects of the ligands.It was found that the ligands strongly affected the optical and electrical properties of CQDs,and the performances of solar cells were enhanced strongly.The optimized hybrid ligands,oleic amine/octyl-phosphine acid/Cd Cl2improved power conversion efficiency(PCE)to much higher of 3.72%for Schottky diode cell and 5.04%for p–n junction cell.These results may be beneficial to design passivation strategy for low-cost and high-performance CQDs solar cells.
基金the National Key Research and Development Program of China(Grant No.2018YFA0703400)the National Natural Science Foundation of China(Grant Nos.11704044 and 11974134)+1 种基金the Jilin Province Outstanding Young Talents Project(Grant No.20190103040JH)the China Postdoctoral Science Foundation(Grant No.2018M631870)。
文摘Gallium arsenide(GaAs),a typical covalent semiconductor,is widely used in the electronic industry,owing to its superior electron transport properties.However,its brittle nature is a drawback that has so far significantly limited its application.An exploration of the structural deformation modes of GaAs under large strain at the atomic level,and the formulation of strategies to enhance its mechanical properties is highly desirable.The stressstrain relations and deformation modes of single-crystal and nanotwinned GaAs under various loading conditions are systematically investigated,using first-principles calculations.Our results show that the ideal strengths of nanotwinned GaAs are 14% and 15% higher than that of single-crystal GaAs under pure and indentation shear strains,respectively,without producing a significantly negative effect in terms of its electronic performance.The enhancement in strength stems from the rearrangement of directional covalent bonds at the twin boundary.Our results offer a fundamental understanding of the mechanical properties of single crystal GaAs,and provide insights into the strengthening mechanism of nanotwinned GaAs,which could prove highly beneficial in terms of developing reliable electronic devices.
文摘目的观察超声引导下星状神经节阻滞(SGB)对乳腺癌患者乳腺癌相关淋巴水肿及术后恢复质量的影响。方法选择2022年10月至2023年10月择期全麻下行乳腺癌改良根治术的女性患者80例,年龄18~64岁,BMI 18.5~25.0 kg/m^(2),ASAⅠ或Ⅱ级。采用随机数字表法将患者随机分为两组:SGB组(S组)和对照组(C组),每组40例。S组术前行超声引导下单次右侧SGB;C组术前仅接受右侧星状神经节超声扫描不进行神经阻滞。记录术后3 d内乳腺癌相关淋巴水肿的发生情况。记录术前1 d和术后1、3 d睡眠时间,术后1、3 d 15项恢复质量评分(QoR-15)及Christensen疲劳评分。记录术后2、8、24 h VAS疼痛评分以及术后24 h内舒芬太尼用量、镇痛泵总按压次数及有效按压次数和补救镇痛例数。记录手术时间、拔管时间、PACU停留时间、术后住院时间、术后腹胀和恶心呕吐的发生情况以及术后神经阻滞相关并发症的发生情况。结果与C组比较,S组术后3 d内乳腺癌相关淋巴水肿发生率明显降低,术后1、3 d睡眠时间明显延长,术后1、3 d QoR-15评分明显升高,Christensen疲劳评分明显降低,术后24 h内舒芬太尼用量、镇疼泵总按压次数及有效按压次数明显减少,术后2、8、24 h VAS疼痛评分明显降低,拔管时间、PACU停留时间和术后住院时间明显缩短,术后腹胀和术后恶心呕吐发生率明显降低(P<0.05)。两组术后24 h内补救镇痛率差异无统计学意义。SGB组无一例发生神经阻滞相关并发症。结论在接受乳腺癌改良根治术的女性患者中术前行超声引导下单次SGB,可以降低乳腺癌相关淋巴水肿的发生率,提高术后恢复质量。
