Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit...Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit NLR family pyrin domain containing protein 3(NLRP3)inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer’s disease.However,little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke.To address this issue in the present study,we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models.First,we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis.We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation.Second,we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus.Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype.Finally,we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin,an NLRP3 agonist,restored the neurotoxic astrocyte phenotype.These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.展开更多
Carbon can change the phase components of low-density steels and influence the mechanical properties.In this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization tre...Carbon can change the phase components of low-density steels and influence the mechanical properties.In this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization treatment was proposed.The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined.Crussard-Jaoul(C-J)analysis was employed to examine the work hardening characteristics during the tensile test.During decarburization by heat treatments,the carbon content within the austenite phase decreased,while Mn and Al were almost unchanged;this made the steel with full austenite transform into the austenite and ferrite dual phase.Meanwhile,(Ti,V)C carbides existed in both matrix phase and the mole fraction almost the same.In addition,the formation of other carbides restrained.Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution.For the steel with the single austinite,the deformation mode of austenite was the dislocation planar glide,resulting in the formation of microbands.For the dual-phase steel,the deformation occurred by the dislocation planar glide of austenite first,with the increase in strain,the cross slip of ferrite took place,forming dislocation cells in ferrite.At the late stage of deformation,the work hardening of austinite increased rapidly,while that of ferrite increased slightly.展开更多
The low-density medium-Mn steel is widely studied and applied in the automobile and construction machinery due to the low costs and high strength-ductility.Adding lightweight elements,such as aluminum,is considered an...The low-density medium-Mn steel is widely studied and applied in the automobile and construction machinery due to the low costs and high strength-ductility.Adding lightweight elements,such as aluminum,is considered an efficient way to reduce the density of the steels.A novel 5Al-5Mn-1.5Si-0.3C(wt%)low-density and high-strengthδ-ferrite/martensite(δ-F/M)steel was designed in this study.The study indicated that the designed steel annealed at 1080℃was characterized by an excellent combination of tensile strength of 1246 MPa and density of 7.24 g/cm^(3).Microscopic characterization shows that the higher prior-austenite volume fraction(i.e.,martensite plus retained austenite)significantly increases the tensile strength,and the strip-like martensite and retained austenite(M&RA)mixture benefits elongation.High martensite fraction owns higher origin geometrically necessary dislocations,contributing to better work-hardening behaviors.Concurrently,the synergistic presence of M&RA mixtures’volume fraction and morphology enhances their capability to absorb stress and obstruct crack propagation,significantly improving mechanical performance.The extended strength formula,accounting for the contribution of the M&RA mixture,is consistent with the quantitative agreement observed in experimental results.These insights provide a valuable technological reference for the knowledge-based design and prediction of the mechanical properties of low-density and high-strength steel.展开更多
It has been widely recognized that the mixing process has significant impacts on the performance of low-density polyethylene(LDPE)reactors due to the rapid radical polymerization occurred in the reactors,but how the m...It has been widely recognized that the mixing process has significant impacts on the performance of low-density polyethylene(LDPE)reactors due to the rapid radical polymerization occurred in the reactors,but how the macro-and micro-mixing affect the reactor performance was still controversial in publications.In this work,a cold-flow LDPE autoclave with multi-feedings was scaled down(1/2)from an industrial reactor and built to systematically investigate the macro-and micro-mixing characteristics of fluid by experiments.Furthermore,the effects of macro-and micro-mixing on the polymerization were comprehensively analyzed.The results showed that according to the delay time t_(d) and macro-mixing times tM calculated from residence time distribution(RTD)curves,the macro-mixing states are significantly different at various axial positions(h/H),especially at lower agitation Reynolds number Re.But with the increase of Re,since the circulation flow in the reactor is strengthened,the t_(d) for each feed gradually decreases to 0,and the t_(M) at different axial positions tend to be identical.For micro-mixing,the qualities of micro-mixing at different axial positions are similar,and the average micro-mixing time t_(m) in the reactor decreases exponentially with the increase of Re.Moreover,a fitting model was established.Through the comparison of the characteristic times of macro-mixing(t_(d),t_(M)),micro-mixing(t_(m))and elementary reactions within the industrial range of Re,it can be concluded that the properties of LDPE products are dominated by the macro-mixing behavior,and the consumption of initiators is affected by both the macro-and micro-mixing behaviors.This conclusion is of great significance for the design,optimization and operation of LDPE reactors.展开更多
Fe-28Mn-(10-12)Al-(0.8-1.4)C(wt.%)steels were designed to investigate the influence of varying Al and C content on precipitation behavior ofκ-carbide and its contribution to the strength of high-Mn low-density steels...Fe-28Mn-(10-12)Al-(0.8-1.4)C(wt.%)steels were designed to investigate the influence of varying Al and C content on precipitation behavior ofκ-carbide and its contribution to the strength of high-Mn low-density steels.Results reveal that both Al and C elements promoteκ-carbide precipitation,with C having a more pronounced effect.In near-rapidly solidified 10Al steel strips,increasing C content from 0.8wt.%to 1.4wt.%raises theκ-carbide size from 9.6 nm to 38.2 nm,accompanied by volume fraction increase from 10.2vol.%to 29.8vol.%.In comparison,the average size and volume fraction ofκ-carbides in 12Al0.8C steel are only 11.4 nm and 17.8vol.%,respectively.Higher Al and C content reduces the lattice mismatch between austenite andκ-carbides,thus promoting nucleation ofκ-carbides.Notably,the increase in C content results in a greater reduction in the Gibbs free energy ofκ-carbide,leading to a stronger driving force forκ-carbide formation.Consequently,as the C content increases from 0.8wt.%to 1.4wt.%,the interaction betweenκ-carbides and dislocations transforms from particle cutting to bypassing,and the maximum precipitation strengthening ofκ-carbides reaches 583 MPa.The construction of the relationship between Al and C content andκ-carbide precipitation in this study would provide valuable insights for alloy design of high-Mn steels.展开更多
The effects of austenite grain size on the deformed microstructure and mechanical properties of an Fe-20Mn-6Al-0.6C-0.15Si(wt.%)low-density steel were investigated.The microstructure of the experimental steel after so...The effects of austenite grain size on the deformed microstructure and mechanical properties of an Fe-20Mn-6Al-0.6C-0.15Si(wt.%)low-density steel were investigated.The microstructure of the experimental steel after solution treatment was single austenitic phase.The austenite grain size increased with solution temperature and time.A model was established to show the relationship between temperature,time and austenite grain size for the experimental steel.In addition,as the solution temperature increased,the strength decreased,while the elongation first increased and then decreased.This decrease in elongation after solution treatment at 1100℃ for 90 min is contributed to the over-coarse austenite grains.However,after solution treatment at 900℃ for 90 min,the strength-elongation product reached the highest value of 44.4 GPa%.As the austenite grain size increased,the intensity of<111>//tensile direction fiber decreased.This was accompanied by a decrease in dislocation density,resulting in a lower fraction of low-angle grain boundaries and a lower work hardening rate.Therefore,the austenite grain size has a critical influence on the mechanical properties of the low-density steels.Coarser grains lead to a lower yield strength due to the Hall-Petch effect and a lower tensile strength because of lower dislocation strengthening.展开更多
BACKGROUND Esophageal cancer(EC)is one of the most common malignancies worldwide,and lymph node(LN)metastasis remains one of the leading causes of EC recurrence.Metabolic disorders critically affect cancer progression...BACKGROUND Esophageal cancer(EC)is one of the most common malignancies worldwide,and lymph node(LN)metastasis remains one of the leading causes of EC recurrence.Metabolic disorders critically affect cancer progression,and lipid levels are closely associated with the occurrence of EC and several other tumor types.This study analyzed pretreatment lipid levels to determine their association with LN metastasis.AIM To dissect the possible mechanisms underlying LN metastasis and clarify the prognostic role of lipid profiles in EC.METHODS Serum lipid levels and clinicopathological information were retrospectively collected from 294 patients,and risk factors for LN metastasis were confirmed using a logistic regression model.Latent factors were explored using information from publicly accessible databases and immunofluorescence and immunohistochemical staining techniques.RESULTS High serum levels of low-density lipoprotein(LDL)cholesterol promote LN metastasis in EC,while high-density lipoprotein cholesterol has the opposite role.Information of a public database revealed that LDL receptors LRP5 and LRP6 are highly expressed in ECs,and LRP6 overexpression positively correlated with the infiltration of B lymphocytes and a poor prognosis.Immunofluorescence and immunohistochemical staining revealed that the expression of LRP6 and infiltrated B lymphocytes in patients with≥1 regional LN metastasis,containing N1-3(N+group)were significantly higher than those in the N0 group.LRP6 was also highly expressed in the B lymphocytes of the N+group.There was no difference in CXCL13 expression between the N+and N0 groups.However,CXCR5 expression was significantly higher in the N0 group than in the N+group.CONCLUSION High serum LDL levels can promote LN metastasis in EC,and the mechanisms may be related to LRP6 expression and the infiltration of B lymphocytes.展开更多
Precipitation strengthening is a pivotal mechanism for enhancing the mechanical properties of low-density alloys.A detailed analysis of microstructural evolution during thermal processing is imperative to thoroughly u...Precipitation strengthening is a pivotal mechanism for enhancing the mechanical properties of low-density alloys.A detailed analysis of microstructural evolution during thermal processing is imperative to thoroughly understand its strengthening behavior.This study employed the Bähr D805L quenching dilatometer system to study the formation,evolution,and impact on the contribution of nano-precipitates on the mechanical behavior of Fe-21Mn-10Al-5Ni-C(nominal composition)low-density alloy during continuous cooling.The study unveiled the precipitation mechanism of nano-particles within the austenite(γ)matrix at cooling rates in the range of 40-0.1℃·s^(-1).Moreover,the addition of Ni in Fe-21Mn-10Al-5Ni-C low-density alloy enhances the atomic size factor,promoting alloy spinodal decomposition and ordering.During slow cooling,B2 phases precipitate along grain boundaries,accompanied by the formation of a precipitation-free zone(PFZ)near the boundaries and the dissolution of some later nucleated small particles.These phenomena are a primary mechanism that suppresses the precipitation of B2 phases within theγmatrix.展开更多
Flexible polymer-based foam sensors have significant potential for application in wearable electronics and motion monitoring.However,these prospects are hindered by the complex and unenvironmentally friendly manufactu...Flexible polymer-based foam sensors have significant potential for application in wearable electronics and motion monitoring.However,these prospects are hindered by the complex and unenvironmentally friendly manufacturing processes.In this study,we employed melt blending and supercritical carbon dioxide foaming to fabricate an ethylene-vinyl acetate copolymer(EVA)/low-density polyethylene(LDPE)/carbon nanotube(CNT)piezoresistive foam sensor.The cross-linking agent bis(tert-butyldioxyisopropyl)benzene and the conductive filler CNT were incorporated into the EVA/LDPE composite,successfully achieving a chemically cross-linked and physically entangled composite structure that significantly enhanced the storage modulus and complex viscosity.Additionally,the compressive strength of EVA/LDPE/CNT foam with 10 parts per hundred rubber(phr)CNT reached 1.37 MPa at 50%compression,marking a 340%increase compared to the 0.31 MPa of the CNT-free sample.Furthermore,the EVA/LDPE/CNT composite foams,which incorporated 10 phr CNT,were prepared under specific foaming conditions,resulting in an ultra-low density of 0.11 g/cm^(3) and a higher sensitivity,with a gauge factor of–2.3.The piezoresistive foam sensors developed in this work could accurately detect human motion,thereby expanding their applications in the field of piezoresistive foam sensors and providing an effective strategy for the advancement of high-performance piezoresistive foam sensors.展开更多
α-Synuclein accumulation and transmission are vital to the pathogenesis of Parkinson's disease,although the mechanisms underlying misfoldedα-synuclein accumulation and propagation have not been conclusively dete...α-Synuclein accumulation and transmission are vital to the pathogenesis of Parkinson's disease,although the mechanisms underlying misfoldedα-synuclein accumulation and propagation have not been conclusively determined.The expression of low-density lipoprotein receptor–related protein 1,which is abundantly expressed in neurons and considered to be a multifunctional endocytic receptor,is elevated in the neurons of patients with Parkinson's disease.However,whether there is a direct link between low-density lipoprotein receptor–related protein 1 andα-synuclein aggregation and propagation in Parkinson's disease remains unclear.Here,we established animal models of Parkinson's disease by inoculating monkeys and mice withα-synuclein pre-formed fibrils and observed elevated low-density lipoprotein receptor–related protein 1 levels in the striatum and substantia nigra,accompanied by dopaminergic neuron loss and increasedα-synuclein levels.However,low-density lipoprotein receptor–related protein 1 knockdown efficiently rescued dopaminergic neurodegeneration and inhibited the increase inα-synuclein levels in the nigrostriatal system.In HEK293A cells overexpressingα-synuclein fragments,low-density lipoprotein receptor–related protein 1 levels were upregulated only when the N-terminus ofα-synuclein was present,whereas anα-synuclein fragment lacking the N-terminus did not lead to low-density lipoprotein receptor–related protein 1 upregulation.Furthermore,the N-terminus ofα-synuclein was found to be rich in lysine residues,and blocking lysine residues in PC12 cells treated withα-synuclein pre-formed fibrils effectively reduced the elevated low-density lipoprotein receptor–related protein 1 andα-synuclein levels.These findings indicate that low-density lipoprotein receptor–related protein 1 regulates pathological transmission ofα-synuclein from the striatum to the substantia nigra in the nigrostriatal system via lysine residues in theα-synuclein N-terminus.展开更多
Loss-of-function variants of low-density lipoprotein receptor-related protein 5(LRP5)can lead to reduced bone formation,culminating in diminished bone mass.Our previous study reported transcription factor osterix(SP7)...Loss-of-function variants of low-density lipoprotein receptor-related protein 5(LRP5)can lead to reduced bone formation,culminating in diminished bone mass.Our previous study reported transcription factor osterix(SP7)-binding sites on the LRP5 promoter and its pivotal role in upregulating LRP5 expression during implant osseointegration.However,the potential role of SP7 in ameliorating LRP5-dependent osteoporosis remained unknown.In this study,we used mice with a conditional knockout(c KO)of LRP5 in mature osteoblasts,which presented decreased osteogenesis.The in vitro experimental results showed that SP7 could promote LRP5 expression,thereby upregulating the osteogenic markers such as alkaline phosphatase(ALP),Runt-related transcription factor 2(Runx2),andβ-catenin(P<0.05).For the in vivo experiment,the SP7 overexpression virus was injected into a bone defect model of LRP5 c KO mice,resulting in increased bone mineral density(BMD)(P<0.001)and volumetric density(bone volume(BV)/total volume(TV))(P<0.001),and decreased trabecular separation(Tb.Sp)(P<0.05).These data suggested that SP7 could ameliorate bone defect healing in LRP5 c KO mice.Our study provides new insights into potential therapeutic opportunities for ameliorating LRP5-dependent osteoporosis.展开更多
In low-density steel,κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains.However,their precipitation within ferrite matrix grains has not been comprehensively explored,and the ...In low-density steel,κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains.However,their precipitation within ferrite matrix grains has not been comprehensively explored,and the second-phase evolution mechanism during aging remains unclear.In this study,the crystallographic characteristics and morphological evolution ofκ-carbides in Fe-28Mn-10Al-0.8C(wt%)low-density steel at different aging temperatures and times and the impacts of these changes on the steels’microhardness and properties were comprehensively analyzed.Under different heat treatment conditions,intragranularκ-carbides exhibited various morpho-logical and crystallographic characteristics,such as acicular,spherical,and short rod-like shapes.At the initial stage of aging,acicularκ-carbides primarily precipitated,accompanied by a few spherical carbides.κ-Carbides grew and coarsened with aging time,the spherical carbides were considerably reduced,and rod-like carbides coarsened.Vickers hardness testing demonstrated that the material’s hardness was affected by the volume fraction,morphology,and size ofκ-carbides.Extended aging at higher temperatures led to an increase in carbide size and volume fraction,resulting in a gradual rise in hardness.During deformation,the primary mechanisms for strengthening were dislocation strengthening and second-phase strengthening.Based on these findings,potential strategies for improving material strength are proposed.展开更多
Low-density lipoprotein receptor-related protein 2(LRP2)is a multifunctional endocytic receptor expressed in epithelial cells.In mammals,it acts as an endocytic receptor that mediates the cellular uptake of cholestero...Low-density lipoprotein receptor-related protein 2(LRP2)is a multifunctional endocytic receptor expressed in epithelial cells.In mammals,it acts as an endocytic receptor that mediates the cellular uptake of cholesterol-containing apolipoproteins to maintain lipid homeostasis.However,little is known about the role of LRP2 in lipid homeostasis in insects.In the present study,we investigated the function of LRP2 in the migratory locust Locusta migratoria(LmLRP2).The mRNA of LmLRP2 is widely distributed in various tissues,including integument,wing pads,foregut,midgut,hindgut,Malpighian tubules and fat body,and the amounts of LmLRP2 transcripts decreased gradually in the early stages and then increased in the late stages before ecdysis during the nymphal developmental stage.Fluorescence immunohistochemistry revealed that the LmLRP2 protein is mainly located in cellular membranes of the midgut and hindgut.Using RNAi to silence LmLRP2 caused molting defects in nymphs(more than 60%),and the neutral lipid was found to accumulate in the midgut and surface of the integument,but not in the fat body,of dsLmLRP2-treated nymphs.The results of a lipidomics analysis showed that the main components of lipids(diglyceride and triglyceride)were significantly increased in the midgut,but decreased in the fat body and hemolymph.Furthermore,the content of total triglyceride was significantly increased in the midgut,but markedly decreased in the fat body and hemolymph in dsLmLRP2-injected nymphs.Our results indicate that LmLRP2 is located in the cellular membranes of midgut cells,and is required for lipid export from the midgut to the hemolymphand fat body in locusts.展开更多
This paper focuses on the relationship between the microstructure and tensile properties of Fe-Mn-Al-C low-density high-strength steel processes by hot-rolling and air-cooling process. The microstructure analysis reve...This paper focuses on the relationship between the microstructure and tensile properties of Fe-Mn-Al-C low-density high-strength steel processes by hot-rolling and air-cooling process. The microstructure analysis reveals that the combination of hot-rolling and air-cooling results in the formation of heterogeneous structures comprising different-sized γ and B_(2) phases in the low-density steel with the addition of nickel (Ni). The addition of Ni promotes the formation of the B_(2) phase and induces the pinning of B_(2) phase particles at the γ grain boundaries. This pinning effect effectively hinders the growth of the γ grains, leading to grain refinement. The tensile test results demonstrate that LDS-5Ni (low-density steel, LDS) exhibits excellent high strength and ductility combination, e.g., a tensile strength of 1535 MPa, yield strength of 1482 MPa, and elongation of 23.3%. These remarkable mechanical properties are primarily attributed to the combined strengthening contributions of grain refinement and duplex nano-sized second-phase precipitation hardening.展开更多
The elemental distribution and microstructure near the surface of high-Mn/Al austenitic low-density steel were investigated after isothermal holding at temperatures of 900-1200℃ in different atmospheres,including air...The elemental distribution and microstructure near the surface of high-Mn/Al austenitic low-density steel were investigated after isothermal holding at temperatures of 900-1200℃ in different atmospheres,including air,N_(2),and N_(2)+CO_(2).No ferrite was formed near the surface of the experimental steel during isothermal holding at 900 and 1000℃ in air,while ferrite was formed near the steel sur-face at holding temperatures of 1100 and 1200℃.The ferrite fraction was larger at 1200℃ because more C and Mn diffused to the sur-face,exuded from the steel,and then reacted with N and O to form oxidation products.The thickness of the compound scale increased owing to the higher diffusion rate at higher temperatures.In addition,after isothermal holding at 1100℃ in N_(2),the Al content near the surface slightly decreased,while the C and Mn contents did not change.Therefore,no ferrite was formed near the surface.However,the near-surface C and Al contents decreased after holding at 1100℃in the N_(2)+CO_(2)mixed atmosphere,resulting in the formation of a small amount of ferrite.The compound scale was thickest in N_(2),followed by the N_(2)+CO_(2)mixed atmosphere,and thinnest in air.Overall,the element loss and ferrite fraction were largest after holding in air at the same temperature.The differences in element loss and ferrite frac-tion between in N_(2) and N_(2)+CO_(2)atmospheres were small,but the compound scale formed in N_(2) was significantly thicker.According to these results,N_(2)+CO_(2)is the ideal heating atmosphere for the industrial production of high-Mn/Al austenitic low-density steel.展开更多
Low-densityδ-quenching and partitioning(δ-QP)steels with excellent strength and ductility have been recently developed.However,there are still rare reports on the formability of δ-QP steels,which are critical for s...Low-densityδ-quenching and partitioning(δ-QP)steels with excellent strength and ductility have been recently developed.However,there are still rare reports on the formability of δ-QP steels,which are critical for satisfying the manufacture of structural parts during the application in automotive industry.In the present work,an 1180 MPa Fe–Mn–Al–C–Nbδ-QP steel with a high ductility was adopted for the stretch–flangeability study.Theδ-QP steel was developed by separated quenching and partitioning processes.A good hole expansion ratio(HER)of 34.9±0.9%was obtained in the quenched steel,but it has been further increased to 52.2%by the tempering treatment.The improved stretch–flangeability was attributed to the enhanced austenite stability and deformation uniformity.On the one hand,the stability of austenite was increased by carbon partitioning during tempering,which reduced crack possibility via the suppression of the fresh martensite formation.On the other hand,the tempering treatment released the internal stress caused by martensitic transformation and reduced the difference in strength among different phases,resulting in an increase in the resistance to crack initiation and propagation.展开更多
The understanding of the impact of high-velocity microparticles on human skin tissue is important for the ad-ministration of drugs during transdermal drug delivery.This paper aims to numerically investigate the dynami...The understanding of the impact of high-velocity microparticles on human skin tissue is important for the ad-ministration of drugs during transdermal drug delivery.This paper aims to numerically investigate the dynamic behavior of human skin tissue under micro-particle impact in transdermal drug delivery.The numerical model was developed based on a coupled smoothed particle hydrodynamics(SPH)and FEM method via commercial FE software RADIOSS.Analytical analysis was conducted applying the Poncelet model and was used as validation data.A hyperelastic one-term Ogden model with one pair of material parameters(μ,α)was implemented for the skin tissue.Sensitivity studies reveal that the effect of parameter α on the penetration process is much more significant than μ.Numerical results correlate well with the analytical curves with various particle diameters and impact velocities,its capability of predicting the penetration process of micro-particle impacts into skin tissues.This work can be further investigated to guide the design of transdermal drug delivery equipment.展开更多
The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation cond...The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation conditions, the shape and position of stirrers, and stirring rate etc., have important influence on the size and distribution of particles. The preparation conditions must be carefully designed and controlled in order to obtain high-quality PS beads. A bow-shaped stirrer is helpful to produce small-sized particles and narrow size distribution, and the upper edge of a stirrer should be set to the same level as the surface of mixture, and the stirring rate should be controlled in the range of 520-600 r/min.展开更多
Aim To study the effect of Isorhapontigenin (Iso) on copper-mediatedperoxidation of human low-density lipoprotein (LDL) and on the toxicity of oxidized LDL (ox-LDL) tomouse macrophages in vitro. Methods Human LDL from...Aim To study the effect of Isorhapontigenin (Iso) on copper-mediatedperoxidation of human low-density lipoprotein (LDL) and on the toxicity of oxidized LDL (ox-LDL) tomouse macrophages in vitro. Methods Human LDL from sera df normal lipidemic donors was separated bysequential ultracentrifugation. The separated human IDL 1 mg·mL^(-1) in phosphate buffer saline, pH7.4, was incubated with cupric sulfate (10 μmol·L^(-1) ) at 37℃ for 10 h in the presence orabsence of various concentrations of Iso. Malondialdehyde (MDA) formation, vitamin E consumption,electrophoretic mobility of LDL, mitochondria] membrane potential of mouse peritoneal macrophages,phagocytosis of neutral red, and release of nitric oxide (NO) from macrophages were determined byvarious methods. Results Iso 1 - 100 μmol·L^(-1) significantly inhibited the increase of MDAformation, vitamin E consumption and electrophoretic mobility of LDL induced by Cu^(2+) in aconcentration-dependent manner. The injury of the mitochondrial membrane potential of mouseperitoneal macrophages due to incubation with ox-LDL (0.1 mg·mL^(-1)) at 37℃ for 12 h was markedlyprotected by 10 μmol·L^(-1) Iso. After pretreat-ment of the macrophages with 10 μmol · L^(-1)of Iso and then exposure to ox-LDL for 4 h, the reduction of phagocytosis of neutral red and releaseof NO in response to lipopolysaccharide (IPS) stimulation were significantly prevented. ConclusionIso has protective action against Cu^(2+) - mediated LDL peroxidation and ox-LDL induced toxicity tomacrophages in vitro.展开更多
In this study, we examined the protective effects of Danshen both on endothelial progenitor cells （EPCs） in patients with hypercholesterolemia and on in-vitro EPCs of healthy volunteers. In the clinical study, we ra...In this study, we examined the protective effects of Danshen both on endothelial progenitor cells （EPCs） in patients with hypercholesterolemia and on in-vitro EPCs of healthy volunteers. In the clinical study, we randomly divided 24 subjects with hypercholesterolemia into two groups （the control group and the Danshen-treated group）. At the end of two weeks of treatment, the EPC cellular functions of both groups were tested. The results indicated that, compared to the control group, EPCs in the Danshen-treated group showed significantly better cellular functions, which was manifested in the cloning number, the proliferation capacity, the number of EPC adhesions, and cell migration. In the subsequent in-vitro experiments, EPCs were treated with vehicle, oxidized low-density lipoprotein （Ox-LDL, 100 pg/ml）, or Ox-LDL （100 pg/ml） plus different concentrations of Danshen （Danshensu 2, 10, or 50 pg/ml, respectively） for 24 h. The results showed that Danshen treatments can prevent the detrimental effects of Ox-LDL on EPC cellular functions measured by proliferation capacity （0.24±0.08, 0.37±0.11, 0.30±0.04 vs. 0.13±0.02, P〈0.05, P〈0.01, and P〈0.01, respectively）, and adhesion ability （63.00_±11.60, 70.00±10.80, 85.50±11.41 vs. 40.50±6.85, all P〈0.01）. Compared to the group treated with Ox-LDL alone, Danshen treatment significantly decreased the lipid peroxidation end product malondialdehyde （MDA） [（4.34±0.54）, （3.98±0.47）, （3.46±0.31） vs. （5.57-±0.64） nmol/ml, all P〈0.01], increased the production of superoxide dismutase （SOD） [（29.74±0.71）, （31.09±0.83）, （30.41±0.65） vs. （14.76±3.99） U/ml, all P〈0.01], and lowered the expression of interleukin-6 （IL-6） [（24.62±7.69）, （27.04±3.14）, （33.38±18.86） vs. （230.67±33.53） pg/ml, all P〈0.01] and tumor necrosis factor-α （TNF-α） [（41.72±6.10）, （17.02±6.82）, （3.73±2.26） vs. （228.71±41.53） pg/ml, all P〈0.01] in Ox-LDL treated EPCs. These results suggest that Danshen may exert a protective effect through its antioxidant and anti-inflammatory features.展开更多
基金supported by the National Natural Science Foundation of China,No.82201460(to YH)Nanjing Medical University Science and Technology Development Fund,No.NMUB20210202(to YH).
文摘Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit NLR family pyrin domain containing protein 3(NLRP3)inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer’s disease.However,little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke.To address this issue in the present study,we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models.First,we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis.We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation.Second,we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus.Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype.Finally,we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin,an NLRP3 agonist,restored the neurotoxic astrocyte phenotype.These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.
基金financially supported by the National Natural Science Foundation of China(Nos.U2141207,52171111,and 52001083)the Youth Talent Project of China National Nuclear Corporation(No.CNNC2021Y-TEPHEU01)+3 种基金the China Postdoctoral Science Foundation(No.2020M681077)the Natural Science Foundation of Heilongjiang,China(No.LH2019E030)the Heilongjiang Postdoctoral Science Foundation,China(No.LBH-Z19125)he Heilongjiang Touyan Innovation Team Program,China,and the Natural Science Foundation of Heilongjiang(No.LH2020E060)。
文摘Carbon can change the phase components of low-density steels and influence the mechanical properties.In this study,a new method to control the carbon content and avoid the formation ofδ-ferrite by decarburization treatment was proposed.The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined.Crussard-Jaoul(C-J)analysis was employed to examine the work hardening characteristics during the tensile test.During decarburization by heat treatments,the carbon content within the austenite phase decreased,while Mn and Al were almost unchanged;this made the steel with full austenite transform into the austenite and ferrite dual phase.Meanwhile,(Ti,V)C carbides existed in both matrix phase and the mole fraction almost the same.In addition,the formation of other carbides restrained.Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution.For the steel with the single austinite,the deformation mode of austenite was the dislocation planar glide,resulting in the formation of microbands.For the dual-phase steel,the deformation occurred by the dislocation planar glide of austenite first,with the increase in strain,the cross slip of ferrite took place,forming dislocation cells in ferrite.At the late stage of deformation,the work hardening of austinite increased rapidly,while that of ferrite increased slightly.
基金supported by the Key Research and Development Program of Hubei Province(No.2021BAA057)the National Natural Science Foundation of China(Nos.U20A20279,12174296 and 12102310)+5 种基金the Major Program(JD)of Hubei Province(No.2023BAA019-5)the Natural Science Foundation of Hubei Province(No.2022CFB474)the Science and Technology Program of Guangxi Province(No.AA22068080)the Taishan Industry Leading Talent Project(No.2020007)the Leading Innovation and Pioneering Team of Zhejiang Province(2021R01020)the 111 Project(No.D18018).
文摘The low-density medium-Mn steel is widely studied and applied in the automobile and construction machinery due to the low costs and high strength-ductility.Adding lightweight elements,such as aluminum,is considered an efficient way to reduce the density of the steels.A novel 5Al-5Mn-1.5Si-0.3C(wt%)low-density and high-strengthδ-ferrite/martensite(δ-F/M)steel was designed in this study.The study indicated that the designed steel annealed at 1080℃was characterized by an excellent combination of tensile strength of 1246 MPa and density of 7.24 g/cm^(3).Microscopic characterization shows that the higher prior-austenite volume fraction(i.e.,martensite plus retained austenite)significantly increases the tensile strength,and the strip-like martensite and retained austenite(M&RA)mixture benefits elongation.High martensite fraction owns higher origin geometrically necessary dislocations,contributing to better work-hardening behaviors.Concurrently,the synergistic presence of M&RA mixtures’volume fraction and morphology enhances their capability to absorb stress and obstruct crack propagation,significantly improving mechanical performance.The extended strength formula,accounting for the contribution of the M&RA mixture,is consistent with the quantitative agreement observed in experimental results.These insights provide a valuable technological reference for the knowledge-based design and prediction of the mechanical properties of low-density and high-strength steel.
基金the support and encouragement of the Key Projects of the Ministry of Industry and Information Technology of China(TC220A04W-3,188)。
文摘It has been widely recognized that the mixing process has significant impacts on the performance of low-density polyethylene(LDPE)reactors due to the rapid radical polymerization occurred in the reactors,but how the macro-and micro-mixing affect the reactor performance was still controversial in publications.In this work,a cold-flow LDPE autoclave with multi-feedings was scaled down(1/2)from an industrial reactor and built to systematically investigate the macro-and micro-mixing characteristics of fluid by experiments.Furthermore,the effects of macro-and micro-mixing on the polymerization were comprehensively analyzed.The results showed that according to the delay time t_(d) and macro-mixing times tM calculated from residence time distribution(RTD)curves,the macro-mixing states are significantly different at various axial positions(h/H),especially at lower agitation Reynolds number Re.But with the increase of Re,since the circulation flow in the reactor is strengthened,the t_(d) for each feed gradually decreases to 0,and the t_(M) at different axial positions tend to be identical.For micro-mixing,the qualities of micro-mixing at different axial positions are similar,and the average micro-mixing time t_(m) in the reactor decreases exponentially with the increase of Re.Moreover,a fitting model was established.Through the comparison of the characteristic times of macro-mixing(t_(d),t_(M)),micro-mixing(t_(m))and elementary reactions within the industrial range of Re,it can be concluded that the properties of LDPE products are dominated by the macro-mixing behavior,and the consumption of initiators is affected by both the macro-and micro-mixing behaviors.This conclusion is of great significance for the design,optimization and operation of LDPE reactors.
基金supported by the National Natural Science Foundation of China(Nos.52301058 and 52271034)the China Postdoctoral Science Foundation(No.2023M732183)+3 种基金the Postdoctoral Fellowship Program of CPSF(No.GZB20230399)the Key scientific and technological project in Ningbo City(No.2022Z056)supported by the Independent Research Project of State Key Laboratory of the Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2023-Z12)the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200).
文摘Fe-28Mn-(10-12)Al-(0.8-1.4)C(wt.%)steels were designed to investigate the influence of varying Al and C content on precipitation behavior ofκ-carbide and its contribution to the strength of high-Mn low-density steels.Results reveal that both Al and C elements promoteκ-carbide precipitation,with C having a more pronounced effect.In near-rapidly solidified 10Al steel strips,increasing C content from 0.8wt.%to 1.4wt.%raises theκ-carbide size from 9.6 nm to 38.2 nm,accompanied by volume fraction increase from 10.2vol.%to 29.8vol.%.In comparison,the average size and volume fraction ofκ-carbides in 12Al0.8C steel are only 11.4 nm and 17.8vol.%,respectively.Higher Al and C content reduces the lattice mismatch between austenite andκ-carbides,thus promoting nucleation ofκ-carbides.Notably,the increase in C content results in a greater reduction in the Gibbs free energy ofκ-carbide,leading to a stronger driving force forκ-carbide formation.Consequently,as the C content increases from 0.8wt.%to 1.4wt.%,the interaction betweenκ-carbides and dislocations transforms from particle cutting to bypassing,and the maximum precipitation strengthening ofκ-carbides reaches 583 MPa.The construction of the relationship between Al and C content andκ-carbide precipitation in this study would provide valuable insights for alloy design of high-Mn steels.
基金supports from National Natural Science Foundation of China(No.U20A20270)China Postdoctoral Science Foundation(No.2022M722486).
文摘The effects of austenite grain size on the deformed microstructure and mechanical properties of an Fe-20Mn-6Al-0.6C-0.15Si(wt.%)low-density steel were investigated.The microstructure of the experimental steel after solution treatment was single austenitic phase.The austenite grain size increased with solution temperature and time.A model was established to show the relationship between temperature,time and austenite grain size for the experimental steel.In addition,as the solution temperature increased,the strength decreased,while the elongation first increased and then decreased.This decrease in elongation after solution treatment at 1100℃ for 90 min is contributed to the over-coarse austenite grains.However,after solution treatment at 900℃ for 90 min,the strength-elongation product reached the highest value of 44.4 GPa%.As the austenite grain size increased,the intensity of<111>//tensile direction fiber decreased.This was accompanied by a decrease in dislocation density,resulting in a lower fraction of low-angle grain boundaries and a lower work hardening rate.Therefore,the austenite grain size has a critical influence on the mechanical properties of the low-density steels.Coarser grains lead to a lower yield strength due to the Hall-Petch effect and a lower tensile strength because of lower dislocation strengthening.
文摘BACKGROUND Esophageal cancer(EC)is one of the most common malignancies worldwide,and lymph node(LN)metastasis remains one of the leading causes of EC recurrence.Metabolic disorders critically affect cancer progression,and lipid levels are closely associated with the occurrence of EC and several other tumor types.This study analyzed pretreatment lipid levels to determine their association with LN metastasis.AIM To dissect the possible mechanisms underlying LN metastasis and clarify the prognostic role of lipid profiles in EC.METHODS Serum lipid levels and clinicopathological information were retrospectively collected from 294 patients,and risk factors for LN metastasis were confirmed using a logistic regression model.Latent factors were explored using information from publicly accessible databases and immunofluorescence and immunohistochemical staining techniques.RESULTS High serum levels of low-density lipoprotein(LDL)cholesterol promote LN metastasis in EC,while high-density lipoprotein cholesterol has the opposite role.Information of a public database revealed that LDL receptors LRP5 and LRP6 are highly expressed in ECs,and LRP6 overexpression positively correlated with the infiltration of B lymphocytes and a poor prognosis.Immunofluorescence and immunohistochemical staining revealed that the expression of LRP6 and infiltrated B lymphocytes in patients with≥1 regional LN metastasis,containing N1-3(N+group)were significantly higher than those in the N0 group.LRP6 was also highly expressed in the B lymphocytes of the N+group.There was no difference in CXCL13 expression between the N+and N0 groups.However,CXCR5 expression was significantly higher in the N0 group than in the N+group.CONCLUSION High serum LDL levels can promote LN metastasis in EC,and the mechanisms may be related to LRP6 expression and the infiltration of B lymphocytes.
基金supported by the CNPC Scientific Research and Technology Development Project(Nos.2021ZZ03,2023ZZ11,2022DQ03-02 and 2020B-4020).
文摘Precipitation strengthening is a pivotal mechanism for enhancing the mechanical properties of low-density alloys.A detailed analysis of microstructural evolution during thermal processing is imperative to thoroughly understand its strengthening behavior.This study employed the Bähr D805L quenching dilatometer system to study the formation,evolution,and impact on the contribution of nano-precipitates on the mechanical behavior of Fe-21Mn-10Al-5Ni-C(nominal composition)low-density alloy during continuous cooling.The study unveiled the precipitation mechanism of nano-particles within the austenite(γ)matrix at cooling rates in the range of 40-0.1℃·s^(-1).Moreover,the addition of Ni in Fe-21Mn-10Al-5Ni-C low-density alloy enhances the atomic size factor,promoting alloy spinodal decomposition and ordering.During slow cooling,B2 phases precipitate along grain boundaries,accompanied by the formation of a precipitation-free zone(PFZ)near the boundaries and the dissolution of some later nucleated small particles.These phenomena are a primary mechanism that suppresses the precipitation of B2 phases within theγmatrix.
基金supported by the National Natural Science Foundation of China(No.52473026)。
文摘Flexible polymer-based foam sensors have significant potential for application in wearable electronics and motion monitoring.However,these prospects are hindered by the complex and unenvironmentally friendly manufacturing processes.In this study,we employed melt blending and supercritical carbon dioxide foaming to fabricate an ethylene-vinyl acetate copolymer(EVA)/low-density polyethylene(LDPE)/carbon nanotube(CNT)piezoresistive foam sensor.The cross-linking agent bis(tert-butyldioxyisopropyl)benzene and the conductive filler CNT were incorporated into the EVA/LDPE composite,successfully achieving a chemically cross-linked and physically entangled composite structure that significantly enhanced the storage modulus and complex viscosity.Additionally,the compressive strength of EVA/LDPE/CNT foam with 10 parts per hundred rubber(phr)CNT reached 1.37 MPa at 50%compression,marking a 340%increase compared to the 0.31 MPa of the CNT-free sample.Furthermore,the EVA/LDPE/CNT composite foams,which incorporated 10 phr CNT,were prepared under specific foaming conditions,resulting in an ultra-low density of 0.11 g/cm^(3) and a higher sensitivity,with a gauge factor of–2.3.The piezoresistive foam sensors developed in this work could accurately detect human motion,thereby expanding their applications in the field of piezoresistive foam sensors and providing an effective strategy for the advancement of high-performance piezoresistive foam sensors.
基金supported by the Natural Science Foundation of Guangxi Zhuang Automomous Region,Nos.2019GXNSFDA245015(to MC),2022GXNSFBA035654(to HL)the National Natural Science Foundation of China,Nos.82360241(to MC),82304876(to HL)+1 种基金Scientific Research and Technology Development Project of Guilin City,Nos.20220139-3(to MC),20210218-5(to HL)Guangxi Medical and Health Key Discipline Construction Project(to QL)。
文摘α-Synuclein accumulation and transmission are vital to the pathogenesis of Parkinson's disease,although the mechanisms underlying misfoldedα-synuclein accumulation and propagation have not been conclusively determined.The expression of low-density lipoprotein receptor–related protein 1,which is abundantly expressed in neurons and considered to be a multifunctional endocytic receptor,is elevated in the neurons of patients with Parkinson's disease.However,whether there is a direct link between low-density lipoprotein receptor–related protein 1 andα-synuclein aggregation and propagation in Parkinson's disease remains unclear.Here,we established animal models of Parkinson's disease by inoculating monkeys and mice withα-synuclein pre-formed fibrils and observed elevated low-density lipoprotein receptor–related protein 1 levels in the striatum and substantia nigra,accompanied by dopaminergic neuron loss and increasedα-synuclein levels.However,low-density lipoprotein receptor–related protein 1 knockdown efficiently rescued dopaminergic neurodegeneration and inhibited the increase inα-synuclein levels in the nigrostriatal system.In HEK293A cells overexpressingα-synuclein fragments,low-density lipoprotein receptor–related protein 1 levels were upregulated only when the N-terminus ofα-synuclein was present,whereas anα-synuclein fragment lacking the N-terminus did not lead to low-density lipoprotein receptor–related protein 1 upregulation.Furthermore,the N-terminus ofα-synuclein was found to be rich in lysine residues,and blocking lysine residues in PC12 cells treated withα-synuclein pre-formed fibrils effectively reduced the elevated low-density lipoprotein receptor–related protein 1 andα-synuclein levels.These findings indicate that low-density lipoprotein receptor–related protein 1 regulates pathological transmission ofα-synuclein from the striatum to the substantia nigra in the nigrostriatal system via lysine residues in theα-synuclein N-terminus.
文摘Loss-of-function variants of low-density lipoprotein receptor-related protein 5(LRP5)can lead to reduced bone formation,culminating in diminished bone mass.Our previous study reported transcription factor osterix(SP7)-binding sites on the LRP5 promoter and its pivotal role in upregulating LRP5 expression during implant osseointegration.However,the potential role of SP7 in ameliorating LRP5-dependent osteoporosis remained unknown.In this study,we used mice with a conditional knockout(c KO)of LRP5 in mature osteoblasts,which presented decreased osteogenesis.The in vitro experimental results showed that SP7 could promote LRP5 expression,thereby upregulating the osteogenic markers such as alkaline phosphatase(ALP),Runt-related transcription factor 2(Runx2),andβ-catenin(P<0.05).For the in vivo experiment,the SP7 overexpression virus was injected into a bone defect model of LRP5 c KO mice,resulting in increased bone mineral density(BMD)(P<0.001)and volumetric density(bone volume(BV)/total volume(TV))(P<0.001),and decreased trabecular separation(Tb.Sp)(P<0.05).These data suggested that SP7 could ameliorate bone defect healing in LRP5 c KO mice.Our study provides new insights into potential therapeutic opportunities for ameliorating LRP5-dependent osteoporosis.
基金supported by the National Key Research and Development Program of China(No.2023YFB3711702).
文摘In low-density steel,κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains.However,their precipitation within ferrite matrix grains has not been comprehensively explored,and the second-phase evolution mechanism during aging remains unclear.In this study,the crystallographic characteristics and morphological evolution ofκ-carbides in Fe-28Mn-10Al-0.8C(wt%)low-density steel at different aging temperatures and times and the impacts of these changes on the steels’microhardness and properties were comprehensively analyzed.Under different heat treatment conditions,intragranularκ-carbides exhibited various morpho-logical and crystallographic characteristics,such as acicular,spherical,and short rod-like shapes.At the initial stage of aging,acicularκ-carbides primarily precipitated,accompanied by a few spherical carbides.κ-Carbides grew and coarsened with aging time,the spherical carbides were considerably reduced,and rod-like carbides coarsened.Vickers hardness testing demonstrated that the material’s hardness was affected by the volume fraction,morphology,and size ofκ-carbides.Extended aging at higher temperatures led to an increase in carbide size and volume fraction,resulting in a gradual rise in hardness.During deformation,the primary mechanisms for strengthening were dislocation strengthening and second-phase strengthening.Based on these findings,potential strategies for improving material strength are proposed.
基金supported by the National Key R&D Program of China (2022YFE0196200)the National Natural Science Foundation of China–Deutsche Forschungsgemeinschaft of Germany (31761133021)+3 种基金the National Natural Science Foundation of China (31970469 and 31701794)the earmarked fund for Modern Agro-industry Technology Research System, China (2023CYJSTX01-20)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi, China (2017104)the Fund for Shanxi “1331 Project”, China
文摘Low-density lipoprotein receptor-related protein 2(LRP2)is a multifunctional endocytic receptor expressed in epithelial cells.In mammals,it acts as an endocytic receptor that mediates the cellular uptake of cholesterol-containing apolipoproteins to maintain lipid homeostasis.However,little is known about the role of LRP2 in lipid homeostasis in insects.In the present study,we investigated the function of LRP2 in the migratory locust Locusta migratoria(LmLRP2).The mRNA of LmLRP2 is widely distributed in various tissues,including integument,wing pads,foregut,midgut,hindgut,Malpighian tubules and fat body,and the amounts of LmLRP2 transcripts decreased gradually in the early stages and then increased in the late stages before ecdysis during the nymphal developmental stage.Fluorescence immunohistochemistry revealed that the LmLRP2 protein is mainly located in cellular membranes of the midgut and hindgut.Using RNAi to silence LmLRP2 caused molting defects in nymphs(more than 60%),and the neutral lipid was found to accumulate in the midgut and surface of the integument,but not in the fat body,of dsLmLRP2-treated nymphs.The results of a lipidomics analysis showed that the main components of lipids(diglyceride and triglyceride)were significantly increased in the midgut,but decreased in the fat body and hemolymph.Furthermore,the content of total triglyceride was significantly increased in the midgut,but markedly decreased in the fat body and hemolymph in dsLmLRP2-injected nymphs.Our results indicate that LmLRP2 is located in the cellular membranes of midgut cells,and is required for lipid export from the midgut to the hemolymphand fat body in locusts.
基金funding from the National Key Technologies Research and Development Program of China(No.2021YFB3703500)the National Natural Science Foundation of China(No.51771014).
文摘This paper focuses on the relationship between the microstructure and tensile properties of Fe-Mn-Al-C low-density high-strength steel processes by hot-rolling and air-cooling process. The microstructure analysis reveals that the combination of hot-rolling and air-cooling results in the formation of heterogeneous structures comprising different-sized γ and B_(2) phases in the low-density steel with the addition of nickel (Ni). The addition of Ni promotes the formation of the B_(2) phase and induces the pinning of B_(2) phase particles at the γ grain boundaries. This pinning effect effectively hinders the growth of the γ grains, leading to grain refinement. The tensile test results demonstrate that LDS-5Ni (low-density steel, LDS) exhibits excellent high strength and ductility combination, e.g., a tensile strength of 1535 MPa, yield strength of 1482 MPa, and elongation of 23.3%. These remarkable mechanical properties are primarily attributed to the combined strengthening contributions of grain refinement and duplex nano-sized second-phase precipitation hardening.
基金gratefully acknowledge the financial support from the National Natural Science Foundation of China(No.U20A20270)China Postdoctoral Science Foundation(No.2022M722486).We would like to thank Dr.Wei Yuan at the Analytical&Testing Center of Wuhan University of Science and Technology for the help on EPMA analyses.
文摘The elemental distribution and microstructure near the surface of high-Mn/Al austenitic low-density steel were investigated after isothermal holding at temperatures of 900-1200℃ in different atmospheres,including air,N_(2),and N_(2)+CO_(2).No ferrite was formed near the surface of the experimental steel during isothermal holding at 900 and 1000℃ in air,while ferrite was formed near the steel sur-face at holding temperatures of 1100 and 1200℃.The ferrite fraction was larger at 1200℃ because more C and Mn diffused to the sur-face,exuded from the steel,and then reacted with N and O to form oxidation products.The thickness of the compound scale increased owing to the higher diffusion rate at higher temperatures.In addition,after isothermal holding at 1100℃ in N_(2),the Al content near the surface slightly decreased,while the C and Mn contents did not change.Therefore,no ferrite was formed near the surface.However,the near-surface C and Al contents decreased after holding at 1100℃in the N_(2)+CO_(2)mixed atmosphere,resulting in the formation of a small amount of ferrite.The compound scale was thickest in N_(2),followed by the N_(2)+CO_(2)mixed atmosphere,and thinnest in air.Overall,the element loss and ferrite fraction were largest after holding in air at the same temperature.The differences in element loss and ferrite frac-tion between in N_(2) and N_(2)+CO_(2)atmospheres were small,but the compound scale formed in N_(2) was significantly thicker.According to these results,N_(2)+CO_(2)is the ideal heating atmosphere for the industrial production of high-Mn/Al austenitic low-density steel.
基金supported by the National Natural Science Foundation of China(Grant Nos.52171108 and 51804072)the Fundamental Research Funds for the Central University(Grant Nos.N2202007 and N2202011)Special thanks are also due to the instrumental or data analysis from Analytical and Testing Center,Northeastern University,China.
文摘Low-densityδ-quenching and partitioning(δ-QP)steels with excellent strength and ductility have been recently developed.However,there are still rare reports on the formability of δ-QP steels,which are critical for satisfying the manufacture of structural parts during the application in automotive industry.In the present work,an 1180 MPa Fe–Mn–Al–C–Nbδ-QP steel with a high ductility was adopted for the stretch–flangeability study.Theδ-QP steel was developed by separated quenching and partitioning processes.A good hole expansion ratio(HER)of 34.9±0.9%was obtained in the quenched steel,but it has been further increased to 52.2%by the tempering treatment.The improved stretch–flangeability was attributed to the enhanced austenite stability and deformation uniformity.On the one hand,the stability of austenite was increased by carbon partitioning during tempering,which reduced crack possibility via the suppression of the fresh martensite formation.On the other hand,the tempering treatment released the internal stress caused by martensitic transformation and reduced the difference in strength among different phases,resulting in an increase in the resistance to crack initiation and propagation.
基金supported by the Nanjing Institute of Technology(Grant No.YKJ202301).
文摘The understanding of the impact of high-velocity microparticles on human skin tissue is important for the ad-ministration of drugs during transdermal drug delivery.This paper aims to numerically investigate the dynamic behavior of human skin tissue under micro-particle impact in transdermal drug delivery.The numerical model was developed based on a coupled smoothed particle hydrodynamics(SPH)and FEM method via commercial FE software RADIOSS.Analytical analysis was conducted applying the Poncelet model and was used as validation data.A hyperelastic one-term Ogden model with one pair of material parameters(μ,α)was implemented for the skin tissue.Sensitivity studies reveal that the effect of parameter α on the penetration process is much more significant than μ.Numerical results correlate well with the analytical curves with various particle diameters and impact velocities,its capability of predicting the penetration process of micro-particle impacts into skin tissues.This work can be further investigated to guide the design of transdermal drug delivery equipment.
文摘The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation conditions, the shape and position of stirrers, and stirring rate etc., have important influence on the size and distribution of particles. The preparation conditions must be carefully designed and controlled in order to obtain high-quality PS beads. A bow-shaped stirrer is helpful to produce small-sized particles and narrow size distribution, and the upper edge of a stirrer should be set to the same level as the surface of mixture, and the stirring rate should be controlled in the range of 520-600 r/min.
文摘Aim To study the effect of Isorhapontigenin (Iso) on copper-mediatedperoxidation of human low-density lipoprotein (LDL) and on the toxicity of oxidized LDL (ox-LDL) tomouse macrophages in vitro. Methods Human LDL from sera df normal lipidemic donors was separated bysequential ultracentrifugation. The separated human IDL 1 mg·mL^(-1) in phosphate buffer saline, pH7.4, was incubated with cupric sulfate (10 μmol·L^(-1) ) at 37℃ for 10 h in the presence orabsence of various concentrations of Iso. Malondialdehyde (MDA) formation, vitamin E consumption,electrophoretic mobility of LDL, mitochondria] membrane potential of mouse peritoneal macrophages,phagocytosis of neutral red, and release of nitric oxide (NO) from macrophages were determined byvarious methods. Results Iso 1 - 100 μmol·L^(-1) significantly inhibited the increase of MDAformation, vitamin E consumption and electrophoretic mobility of LDL induced by Cu^(2+) in aconcentration-dependent manner. The injury of the mitochondrial membrane potential of mouseperitoneal macrophages due to incubation with ox-LDL (0.1 mg·mL^(-1)) at 37℃ for 12 h was markedlyprotected by 10 μmol·L^(-1) Iso. After pretreat-ment of the macrophages with 10 μmol · L^(-1)of Iso and then exposure to ox-LDL for 4 h, the reduction of phagocytosis of neutral red and releaseof NO in response to lipopolysaccharide (IPS) stimulation were significantly prevented. ConclusionIso has protective action against Cu^(2+) - mediated LDL peroxidation and ox-LDL induced toxicity tomacrophages in vitro.
基金Project (No.2007A142) supported by the Health Department of Zhejiang Province,China
文摘In this study, we examined the protective effects of Danshen both on endothelial progenitor cells （EPCs） in patients with hypercholesterolemia and on in-vitro EPCs of healthy volunteers. In the clinical study, we randomly divided 24 subjects with hypercholesterolemia into two groups （the control group and the Danshen-treated group）. At the end of two weeks of treatment, the EPC cellular functions of both groups were tested. The results indicated that, compared to the control group, EPCs in the Danshen-treated group showed significantly better cellular functions, which was manifested in the cloning number, the proliferation capacity, the number of EPC adhesions, and cell migration. In the subsequent in-vitro experiments, EPCs were treated with vehicle, oxidized low-density lipoprotein （Ox-LDL, 100 pg/ml）, or Ox-LDL （100 pg/ml） plus different concentrations of Danshen （Danshensu 2, 10, or 50 pg/ml, respectively） for 24 h. The results showed that Danshen treatments can prevent the detrimental effects of Ox-LDL on EPC cellular functions measured by proliferation capacity （0.24±0.08, 0.37±0.11, 0.30±0.04 vs. 0.13±0.02, P〈0.05, P〈0.01, and P〈0.01, respectively）, and adhesion ability （63.00_±11.60, 70.00±10.80, 85.50±11.41 vs. 40.50±6.85, all P〈0.01）. Compared to the group treated with Ox-LDL alone, Danshen treatment significantly decreased the lipid peroxidation end product malondialdehyde （MDA） [（4.34±0.54）, （3.98±0.47）, （3.46±0.31） vs. （5.57-±0.64） nmol/ml, all P〈0.01], increased the production of superoxide dismutase （SOD） [（29.74±0.71）, （31.09±0.83）, （30.41±0.65） vs. （14.76±3.99） U/ml, all P〈0.01], and lowered the expression of interleukin-6 （IL-6） [（24.62±7.69）, （27.04±3.14）, （33.38±18.86） vs. （230.67±33.53） pg/ml, all P〈0.01] and tumor necrosis factor-α （TNF-α） [（41.72±6.10）, （17.02±6.82）, （3.73±2.26） vs. （228.71±41.53） pg/ml, all P〈0.01] in Ox-LDL treated EPCs. These results suggest that Danshen may exert a protective effect through its antioxidant and anti-inflammatory features.
