Isogeometric analysis(IGA),an approach that integrates CAE into conventional CAD design tools,has been used in structural optimization for 10 years,with plenty of excellent research results.This paper provides a compr...Isogeometric analysis(IGA),an approach that integrates CAE into conventional CAD design tools,has been used in structural optimization for 10 years,with plenty of excellent research results.This paper provides a comprehensive review on isogeometric shape and topology optimization,with a brief coverage of size optimization.For isogeometric shape optimization,attention is focused on the parametrization methods,mesh updating schemes and shape sensitivity analyses.Some interesting observations,e.g.the popularity of using direct(differential)method for shape sensitivity analysis and the possibility of developing a large scale,seamlessly integrated analysis-design platform,are discussed in the framework of isogeometric shape optimization.For isogeometric topology optimization(ITO),we discuss different types of ITOs,e.g.ITO using SIMP(Solid Isotropic Material with Penalization)method,ITO using level set method,ITO using moving morphable com-ponents(MMC),ITO with phase field model,etc.,their technical details and applications such as the spline filter,multi-resolution approach,multi-material problems and stress con-strained problems.In addition to the review in the last 10 years,the current developmental trend of isogeometric structural optimization is discussed.展开更多
Focusing on the structural optimization of auxetic materials using data-driven methods,a back-propagation neural network(BPNN)based design framework is developed for petal-shaped auxetics using isogeometric analysis.A...Focusing on the structural optimization of auxetic materials using data-driven methods,a back-propagation neural network(BPNN)based design framework is developed for petal-shaped auxetics using isogeometric analysis.Adopting a NURBSbased parametric modelling scheme with a small number of design variables,the highly nonlinear relation between the input geometry variables and the effective material properties is obtained using BPNN-based fitting method,and demonstrated in this work to give high accuracy and efficiency.Such BPNN-based fitting functions also enable an easy analytical sensitivity analysis,in contrast to the generally complex procedures of typical shape and size sensitivity approaches.展开更多
Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginner...Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginners,opensource codes are undoubtedly the best alternative to learning TO,which can elaborate the implementation of a method in detail and easily engage more people to employ and extend the method.In this paper,we present a summary of various open-source codes and related literature on TO methods,including solid isotropic material with penalization(SIMP),evolutionary method,level set method(LSM),moving morphable components/voids(MMC/MMV)methods,multiscale topology optimization method,etc.Simultaneously,we classify the codes into five levels,fromeasy to difficult,depending on their difficulty,so that beginners can get started and understand the form of code implementation more quickly.展开更多
Poly（ethylene glycol） methyl ether methacrylate（PEGMA） was grafted on fluorosilicone acrylate rigid gas permissible contact lens surface by means of argon plasma induced polymerization to improve surface hydrophil...Poly（ethylene glycol） methyl ether methacrylate（PEGMA） was grafted on fluorosilicone acrylate rigid gas permissible contact lens surface by means of argon plasma induced polymerization to improve surface hydrophilicity and reduce protein adsorption.The surface properties were characterized by contact angle measurement,x-ray photoelectron spectroscopy（XPS） and atomic force microscopy respectively.The surface protein adsorption was evaluated by lysozyme solution immersion and XPS analysis.The results indicated that a thin layer of PEGMA was successfully grafted.The surface hydrophilicity was bettered and surface free energy increased.The lysozyme adsorption on the lens surface was reduced greatly.展开更多
Strain hardening cement-based composites(SHCC)beam externally bonded with glass fiber-reinforced polymer(FRP)plate was examined under three-point flexural test.The effects of the type of substrate used(plain cement mo...Strain hardening cement-based composites(SHCC)beam externally bonded with glass fiber-reinforced polymer(FRP)plate was examined under three-point flexural test.The effects of the type of substrate used(plain cement mortar vs.SHCC),the use or not of a FRP plate to strengthen the SHCC beam,and the thickness of the FRP plate on the flexural performances were studied.Results show that the ultimate load of SHCC beams strengthened with FRP plate has improved greatly in comparison with plain SHCC beams.The deformation capacity of beams makes little change with an increase in the thickness of FRP plates.The formation of multiple flexural-shear cracks(MFSC)is the unique feature of SHCC beams bonded with FRP plates under three-point bending.The debonding of the FRP plate is initiated from MFSC.The initiated debonding area(IDA)is formed by the joint points of the flexural-shear cracks with the FRP plate.Then the debonding strain is represented using the average strain of FRP plate within IDA,which decreases with an increase of FRP plate thickness.The experimental values of the debonding strain of SHCC beam reinforced with FRP plate are close to those predicted by the JSCE’s equation.展开更多
Additive manufacturing(AM),adding materials layer by layer,can be used to produce objects of almost any shape or geometry.However,AM techniques cannot accurately build parts with large overhangs,especially for the lar...Additive manufacturing(AM),adding materials layer by layer,can be used to produce objects of almost any shape or geometry.However,AM techniques cannot accurately build parts with large overhangs,especially for the large features close to horizontal,hanging over the void.The overhangs will make the manufactured model deviate from the design model,which will result in the performance of the manufactured model that cannot satisfy the design requirements.In this paper,we will propose a new finite element(FE)analysis model that includes the manufacturing errors by mimicking the AM layer by layer construction process.In such FE model,an overhang coefficient is introduced to each FE,which is defined by the support elements in the lower layer.By mimicking the AM process from the bottom layer to the top layer,all the FE properties are updated based on their overhang coefficients,which makes the computational model be able to predict the manufactured model with manufacturing errors.The proposed model can be used to predict the performance of the AM objects in the design stage,which will help the designers to improve their design by the simulation results.展开更多
Inspired by the constitution of things in the natural world,three-dimensional (3D)nanofiber scaffold/cells complex was constructed via the combination of electrospinning technology and origami techniques.The nanofiber...Inspired by the constitution of things in the natural world,three-dimensional (3D)nanofiber scaffold/cells complex was constructed via the combination of electrospinning technology and origami techniques.The nanofiber boxes prepared by origami provided a limited space for the layer-by-layer nanofiber films,and the human fetal osteoblasts (hFOBs)seeded on the both sides of the nanofiber films were expected to facilitate the bonding,of the adjacent nanofiber films through the secretion of extracellular matrix.Specifically,the hFOBs presented 3D distribution in the nanofiber scaffold,and they can stretch across the gaps between the adjacent nanofiber films,forming the cell layers and filling the whole 3D nanofiber scaffold.Eventually,a 3D block composed of electrospun nanofiber scaffold and cells was obtained',which possesses potential applications in bone tissue engineering.Interestingly,we also created 3D nanofiber structures that range from simple forms to intricate architectures via origami,indicating that the combination of electrospinning technology and origami techniques is a feasible method for the 3D construction of tissue engineering scaffolds.展开更多
A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solut...A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.展开更多
As a key technology in the advanced manufacturing field,additive manufacturing(AM)technology introduces a new design concept that is guided by function rather than by manufacturing,promoting the rapid development of t...As a key technology in the advanced manufacturing field,additive manufacturing(AM)technology introduces a new design concept that is guided by function rather than by manufacturing,promoting the rapid development of the high-tech industry.However,as-fabricated parts have an unstable performance in quality due to rapid heating and rapid cooling induced by energy source.Therefore,quality control of the manufacturing process,which is mainly studied by numerical simulation,is one of the most active research topics in the AM field.In the view of increasing attention in AM technology,this special issue contributes to highlighting recent challenges and developments of AM-based design and simulation,with focuses on microstructure stability and evolution,multi-physics problems and process enhancements.展开更多
Isogeometric analysis(IGA),which aims at integrating CAD and CAE models,is one of the most active research topics in both computational mechanics and computer-aided geometric design.The rapidly growing interests in IG...Isogeometric analysis(IGA),which aims at integrating CAD and CAE models,is one of the most active research topics in both computational mechanics and computer-aided geometric design.The rapidly growing interests in IGA has led to profound developments of relevant theories and applications,one of which being structural optimization.With the rapid growth of researches in IGA,this special issue contributes to highlight recent developments,challenges and opportunities of IGA and IGA-based structural design optimization,with focuses on theory development,numerical implementations and potential applications.展开更多
For enhancing the activity of Ni/TiO2-SAPO-11 catalyst, SAPO-11, the precursor was prepared by hydrothermal crystallization, and TiO2-SAPO-11 complex carrier was prepared by sol-gel method, then Ni/TiO2-SAPO-11 was pr...For enhancing the activity of Ni/TiO2-SAPO-11 catalyst, SAPO-11, the precursor was prepared by hydrothermal crystallization, and TiO2-SAPO-11 complex carrier was prepared by sol-gel method, then Ni/TiO2-SAPO-11 was produced by the final product. The catalytic performance of Ni/TiO2-SAPO-11 was studied in n-heptane isomerization, and the impact of catalyst preparation conditions on n-heptane isomerization was discussed in detail. The results showed that, with 20% of TiO2 composition, 2% of Ni capacity percentage and calcined temperature at 500°C, conversion of n-heptane and isomerization selectivity was up to 40.94% and 88.97% respectively.展开更多
Mercury(Hg),especially methylmercury(MeHg),accumulation in rice grain due to rice paddy possessing conditions conducive to Hg methylation has led to human Hg exposure through consumption of rice-based daily meals.In a...Mercury(Hg),especially methylmercury(MeHg),accumulation in rice grain due to rice paddy possessing conditions conducive to Hg methylation has led to human Hg exposure through consumption of rice-based daily meals.In addition to being a food staple,rice is widely used as a raw material to produce a vast variety of processed food products.Little is known about Hg levels in snacking rice-food products and potential Hg exposure from consumption of them,besides previous studies on infant rice cereals.Aiming to provide complementary information for a more complete assessment on Hg exposure risk originated from Hgcontaining rice,this study determined total Hg(THg)and MeHg levels in 195 rice-containing and rice-free processed food products covering all major types of snack foods marketed in China and the estimated daily intake(EDI)of dietary Hg from the consumption of these foods.The results clearly showed THg and MeHg contents in rice-containing foods were significantly higher than rice-free products,suggesting the transfer of Hg and MeHg from the rice to the end products,even after manufacturing processes.Moreover,significant positive correlations were observed between THg,MeHg,or MeHg/THg ratio and rice content for samples containing multiple grains as ingredients,further indicating the deciding role of rice for Hg levels in the end food products.Although the EDI of THg and MeHg via ricebased food products were relatively low compared to the reference dose,it should be considered these snacking food products would contribute additive Hg intake outside of the daily regular meals.展开更多
Rheumatoid arthritis(RA)is a severe autoimmune disease with symptoms including synovial inflammation,cartilage erosion,and bone loss in RA lesions,which eventually lead to joint deformity and function loss.Most curren...Rheumatoid arthritis(RA)is a severe autoimmune disease with symptoms including synovial inflammation,cartilage erosion,and bone loss in RA lesions,which eventually lead to joint deformity and function loss.Most current treatments fail to achieve satisfying therapeutic outcomes with some adverse effects.Extracellular vesicles derived from apoptotic cells(apoEVs)have emerged as important mediators in intercellular communication regulating diverse physiological and pathological processes.In this study,we investigated the therapeutic efficacy of macrophage-derived and osteoclast-derived apoEVs(Mφ-apoEVs and OC-apoEVs)on RA.The in vitro results showed that both Mφ-apoEVs and OC-apoEVs induced macrophage repolarization toward the anti-inflammatory M2 phenotype,promoted chondrocyte functions and chondrogenesis,and inhibited osteoclast formation and maturation.In addition,OC-apoEVs promoted osteogenic differentiation.The in vivo study on the CIA mouse model further demonstrated that apoEVs could couple various functions and exert synergistic effects on the joint with RA,as evidenced by the regression of synovial inflammation,the reversal of cartilage damage and bone erosion,and the preservation of joint structure.These findings demonstrated that Mφ-apoEVs and OC-apoEVs contributed to restoring the homeostasis of the overall microenvironment in the RA joint and highlighted their potential application as a promising alternative to treat RA.展开更多
The migration mechanisms,sources,and environmental risks of 29 legacy and emerging perfluorinated and polyfluoroalkyl species present in an oxidation pond(Ya'Er Lake)were investigated for treating sewage based on ...The migration mechanisms,sources,and environmental risks of 29 legacy and emerging perfluorinated and polyfluoroalkyl species present in an oxidation pond(Ya'Er Lake)were investigated for treating sewage based on the analysis of their occurrence and distribution.The concentration of per-and polyfluoroalkyl substances(PFAS)in pond area was between0.30 and 63.2 ng/g dw(dry weight),with the overall average concentration of 8.00 ng/g dw.Notably,the PFAS concentrations in the surface sediments near the sewage outlet in Pond-1(50.2 ng/g dw)and Pond-5(average 15.1 ng/g dw)were 1–2 orders of magnitude higher than those in other areas.In general,the legacy PFAS,i.e.,perfluorooctane sulfonic acid was considered to be the major pollutant in the polluted area,on average,accounting for 73.0%of the total concentration of PFAS pollutants.By evaluating the regional distribution of different PFAS homologs,the short-chain PFAS pollutants with lower K_(ow)were found to migrate farther in both horizontal and vertical directions.The sewage outlets in Pond-1 and Pond-5are the main pollution sources in polluted area and the emerging PFAS pollutants in Pond-5have replaced the legacy PFAS pollutants as the main pollutants.Based on positive matrix factorization analysis,three main industrial sources of PFAS pollutants in the study area were identified:protective coating,fire-fighting,and food packaging sources.Moreover,the environmental risk assessment results showed that most study areas exhibited medium environmental risk(0.01≤Risk quotient(RQ)<1),indicating that the ecological environment risks in this area need further attention.展开更多
The classical 3D-printed scaffolds have attracted enormous interests in bone regeneration due to the customized structural and mechanical adaptability to bone defects.However,the pristine scaffolds still suffer from t...The classical 3D-printed scaffolds have attracted enormous interests in bone regeneration due to the customized structural and mechanical adaptability to bone defects.However,the pristine scaffolds still suffer from the absence of dynamic and bioactive microenvironment that is analogous to natural extracellular matrix(ECM)to regulate cell behaviour and promote tissue regeneration.To address this challenge,we develop a black phosphorus nanosheets-enabled dynamic DNA hydrogel to integrate with 3D-printed scaffold to build a bioactive gel-scaffold construct to achieve enhanced angiogenesis and bone regeneration.The black phosphorus nanosheets reinforce the mechanical strength of dynamic self-healable hydrogel and endow the gel-scaffold construct with preserved protein binding to achieve sustainable delivery of growth factor.We further explore the effects of this activated construct on both human umbilical vein endothelial cells(HUVECs)and mesenchymal stem cells(MSCs)as well as in a critical-sized rat cranial defect model.The results confirm that the gel-scaffold construct is able to promote the growth of mature blood vessels as well as induce osteogenesis to promote new bone formation,indicating that the strategy of nano-enabled dynamic hydrogel integrated with 3D-printed scaffold holds great promise for bone tissue engineering.展开更多
Bone is an important part of the human body structure and plays a vital role in human health.A microfluidic chip that can simulate the structure and function of bone will provide a platform for bone-related biomedical...Bone is an important part of the human body structure and plays a vital role in human health.A microfluidic chip that can simulate the structure and function of bone will provide a platform for bone-related biomedical research.Hydroxyapatite(HA),a bioactive ceramic material,has a similar structure and composition to bone mineralization products.In this study,we used HA as a microfluidic chip component to provide a highly bionic bone environment.HA substrates with different microchannel structures were printed by using ceramic stereolithography(SLA)technology,and the minimum trench width was 50μm.The HA substrate with microchannels was sealed by a thin polydimethylsiloxane(PDMS)layer to make a HA-PDMS microfluidic chip.Cell culture experiments demonstrated that compared with PDMS,HA was more conducive to the proliferation and osteogenic differentiation of the human foetal osteoblast cell line(hFOB).In addition,the concentration gradient of the model drug doxorubicin hydrochloride(DOX)was successfully generated on a Christmas tree structure HA-PDMS chip,and the half maximal inhibitory concentration(IC50)of DOX was determined.The findings of this study indicate that the HA-PDMS microfluidic chip has great potential in the field of high-throughput bonerelated drug screening and bone-related research.展开更多
Calcium phosphate bio-ceramics are osteo-conductive,but it remains a challenge to promote the induction of bone augmentation and capillary formation.The surface micro/nano-topography of materials can be recognized by ...Calcium phosphate bio-ceramics are osteo-conductive,but it remains a challenge to promote the induction of bone augmentation and capillary formation.The surface micro/nano-topography of materials can be recognized by cells and then the cell fate are mediated.Traditional regulation methods of carving surface structures on bio-ceramics employ mineral reagents and organic additives,which might introduce impurity phases and affect the biological results.In a previous study,a facile and novel method was utilized with ultrapure water as the unique reagent for hydrothermal treatment,and a uniform hydroxyapatite(HAp)surface layer was constructed on composite ceramics(β-TCP/CaSiO_(3))in situ.Further combined with 3D printing technology,biomimetic hierarchical structure scaffolds were fabricated with interconnected porous composite ceramic scaffolds as the architecture and micro/nano-rod hybrid HAp as the surface layer.The obtained HAp surface layer favoured cell adhesion,alleviated the cytotoxicity of precursor scaffolds,and upregulated the cellular differentiation of mBMSCs and gene expression of HUVECs in vitro.In vivo studies showed that capillary formation,bone augmentation and new bone matrix formation were upregulated after the HAp surface layer was obtained,and the results confirmed that the fabricated biomimetic hierarchical structure scaffold could be an effective candidate for bone regeneration.展开更多
Bone bionics and structural engineering have sparked a broad interest in optimizing artificial scaffolds for better bone regeneration.However,the mechanism behind scaffold pore morphology-regulated bone regeneration r...Bone bionics and structural engineering have sparked a broad interest in optimizing artificial scaffolds for better bone regeneration.However,the mechanism behind scaffold pore morphology-regulated bone regeneration remains unclear,making the structure design of scaffolds for bone repair challenging.To address this issue,we have carefully assessed diverse cell behaviors of bone mesenchymal stem cells(BMSCs)on theβ-tricalcium phosphate(β-TCP)scaffolds with three representative pore morphologies(i.e.,cross column,diamond,and gyroid pore unit,respectively).Among the scaffolds,BMSCs on theβ-TCP scaffold with diamond pore unit(designated as D-scaffold)demonstrated enhanced cytoskeletal forces,elongated nucleus,faster cell mobility,and better osteogenic differentiation potential(for example,the alkaline phosphatase expression level in D-scaffold were 1.5-2 times higher than other groups).RNA-sequencing analysis and signaling pathway intervention revealed that Ras homolog gene family A(RhoA)/Rho-associated kinase-2(ROCK2)has in-depth participated in the pore morphology-mediated BMSCs behaviors,indicating an important role of mechanical signaling transduction in scaffold-cell interactions.Finally,femoral condyle defect repair results showed that D-scaffold could effectively promote endogenous bone regeneration,of which the osteogenesis rate was 1.2-1.8 times higher than the other groups.Overall,this work provides insights into pore morphology-mediated bone regeneration mechanisms for developing novel bioadaptive scaffold designs.展开更多
基金This work was supported by National Natural Science Foundation of China(51705158)the Fundamental Research Funds for the Central Universities(2018MS45)Open Funds of National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials(2018005).
文摘Isogeometric analysis(IGA),an approach that integrates CAE into conventional CAD design tools,has been used in structural optimization for 10 years,with plenty of excellent research results.This paper provides a comprehensive review on isogeometric shape and topology optimization,with a brief coverage of size optimization.For isogeometric shape optimization,attention is focused on the parametrization methods,mesh updating schemes and shape sensitivity analyses.Some interesting observations,e.g.the popularity of using direct(differential)method for shape sensitivity analysis and the possibility of developing a large scale,seamlessly integrated analysis-design platform,are discussed in the framework of isogeometric shape optimization.For isogeometric topology optimization(ITO),we discuss different types of ITOs,e.g.ITO using SIMP(Solid Isotropic Material with Penalization)method,ITO using level set method,ITO using moving morphable com-ponents(MMC),ITO with phase field model,etc.,their technical details and applications such as the spline filter,multi-resolution approach,multi-material problems and stress con-strained problems.In addition to the review in the last 10 years,the current developmental trend of isogeometric structural optimization is discussed.
基金National Natural Science Foundation of China(Grant Nos.51705158 and 51805174)the Fundamental Research Funds for the Central Universities(Grant Nos.2018MS45 and 2019MS059)。
文摘Focusing on the structural optimization of auxetic materials using data-driven methods,a back-propagation neural network(BPNN)based design framework is developed for petal-shaped auxetics using isogeometric analysis.Adopting a NURBSbased parametric modelling scheme with a small number of design variables,the highly nonlinear relation between the input geometry variables and the effective material properties is obtained using BPNN-based fitting method,and demonstrated in this work to give high accuracy and efficiency.Such BPNN-based fitting functions also enable an easy analytical sensitivity analysis,in contrast to the generally complex procedures of typical shape and size sensitivity approaches.
基金supported by the National Key R&D Program of China[Grant Number 2020YFB1708300]the National Natural Science Foundation of China[Grant Number 52075184].
文摘Topology optimization(TO),a numerical technique to find the optimalmaterial layoutwith a given design domain,has attracted interest from researchers in the field of structural optimization in recent years.For beginners,opensource codes are undoubtedly the best alternative to learning TO,which can elaborate the implementation of a method in detail and easily engage more people to employ and extend the method.In this paper,we present a summary of various open-source codes and related literature on TO methods,including solid isotropic material with penalization(SIMP),evolutionary method,level set method(LSM),moving morphable components/voids(MMC/MMV)methods,multiscale topology optimization method,etc.Simultaneously,we classify the codes into five levels,fromeasy to difficult,depending on their difficulty,so that beginners can get started and understand the form of code implementation more quickly.
基金supported by National Natural Science Foundation of China(No.51273072)
文摘Poly（ethylene glycol） methyl ether methacrylate（PEGMA） was grafted on fluorosilicone acrylate rigid gas permissible contact lens surface by means of argon plasma induced polymerization to improve surface hydrophilicity and reduce protein adsorption.The surface properties were characterized by contact angle measurement,x-ray photoelectron spectroscopy（XPS） and atomic force microscopy respectively.The surface protein adsorption was evaluated by lysozyme solution immersion and XPS analysis.The results indicated that a thin layer of PEGMA was successfully grafted.The surface hydrophilicity was bettered and surface free energy increased.The lysozyme adsorption on the lens surface was reduced greatly.
基金the National Key Research and Development Programof China(2020YFB1708300)NationalNatural Science Foundation of China(52075184)+1 种基金Natural Science Foundation of Hubei Province(2019CFA059)Tencent XPLORER PRIZE.
基金This work is supported by National Natural Science Foundation of China(51608406)the Fundamental Research Funds for the Central Universities(201114013).
文摘Strain hardening cement-based composites(SHCC)beam externally bonded with glass fiber-reinforced polymer(FRP)plate was examined under three-point flexural test.The effects of the type of substrate used(plain cement mortar vs.SHCC),the use or not of a FRP plate to strengthen the SHCC beam,and the thickness of the FRP plate on the flexural performances were studied.Results show that the ultimate load of SHCC beams strengthened with FRP plate has improved greatly in comparison with plain SHCC beams.The deformation capacity of beams makes little change with an increase in the thickness of FRP plates.The formation of multiple flexural-shear cracks(MFSC)is the unique feature of SHCC beams bonded with FRP plates under three-point bending.The debonding of the FRP plate is initiated from MFSC.The initiated debonding area(IDA)is formed by the joint points of the flexural-shear cracks with the FRP plate.Then the debonding strain is represented using the average strain of FRP plate within IDA,which decreases with an increase of FRP plate thickness.The experimental values of the debonding strain of SHCC beam reinforced with FRP plate are close to those predicted by the JSCE’s equation.
基金This work has been supported by National Natural Science Foundation of China(51705158)Guangdong Basic and Applied Basic Research Foundation(2019A1515011783)the Fundamental Research Funds for the Central Universities(2018MS45).
文摘Additive manufacturing(AM),adding materials layer by layer,can be used to produce objects of almost any shape or geometry.However,AM techniques cannot accurately build parts with large overhangs,especially for the large features close to horizontal,hanging over the void.The overhangs will make the manufactured model deviate from the design model,which will result in the performance of the manufactured model that cannot satisfy the design requirements.In this paper,we will propose a new finite element(FE)analysis model that includes the manufacturing errors by mimicking the AM layer by layer construction process.In such FE model,an overhang coefficient is introduced to each FE,which is defined by the support elements in the lower layer.By mimicking the AM process from the bottom layer to the top layer,all the FE properties are updated based on their overhang coefficients,which makes the computational model be able to predict the manufactured model with manufacturing errors.The proposed model can be used to predict the performance of the AM objects in the design stage,which will help the designers to improve their design by the simulation results.
基金the National Natural Science Foundation of China (51232002,51502095,31771027)the Guangdong Natural Science Funds for Distinguished Young Scholar (2016A030306018)the Guangdong Natural Science Funds (2017B090911008).
文摘Inspired by the constitution of things in the natural world,three-dimensional (3D)nanofiber scaffold/cells complex was constructed via the combination of electrospinning technology and origami techniques.The nanofiber boxes prepared by origami provided a limited space for the layer-by-layer nanofiber films,and the human fetal osteoblasts (hFOBs)seeded on the both sides of the nanofiber films were expected to facilitate the bonding,of the adjacent nanofiber films through the secretion of extracellular matrix.Specifically,the hFOBs presented 3D distribution in the nanofiber scaffold,and they can stretch across the gaps between the adjacent nanofiber films,forming the cell layers and filling the whole 3D nanofiber scaffold.Eventually,a 3D block composed of electrospun nanofiber scaffold and cells was obtained',which possesses potential applications in bone tissue engineering.Interestingly,we also created 3D nanofiber structures that range from simple forms to intricate architectures via origami,indicating that the combination of electrospinning technology and origami techniques is a feasible method for the 3D construction of tissue engineering scaffolds.
文摘A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.
基金supported by High-level Personnel Special Support Plan of Guangdong Province(2016TQ03X289).
文摘As a key technology in the advanced manufacturing field,additive manufacturing(AM)technology introduces a new design concept that is guided by function rather than by manufacturing,promoting the rapid development of the high-tech industry.However,as-fabricated parts have an unstable performance in quality due to rapid heating and rapid cooling induced by energy source.Therefore,quality control of the manufacturing process,which is mainly studied by numerical simulation,is one of the most active research topics in the AM field.In the view of increasing attention in AM technology,this special issue contributes to highlighting recent challenges and developments of AM-based design and simulation,with focuses on microstructure stability and evolution,multi-physics problems and process enhancements.
基金This work has been supported by National Natural Science Foundation of China(51705158),Guangdong Basic and Applied Basic Research Foundation(2019A1515011783)Guangdong Regular Institutions of Characteristic Innovation Project(2017KTSCX176)KEY Laboratory of Robotics and Intelligent Equipment of Guangdong Regular Institutions of Higher Education(2017KSYS009).These supports are gratefully acknowledged.
文摘Isogeometric analysis(IGA),which aims at integrating CAD and CAE models,is one of the most active research topics in both computational mechanics and computer-aided geometric design.The rapidly growing interests in IGA has led to profound developments of relevant theories and applications,one of which being structural optimization.With the rapid growth of researches in IGA,this special issue contributes to highlight recent developments,challenges and opportunities of IGA and IGA-based structural design optimization,with focuses on theory development,numerical implementations and potential applications.
文摘For enhancing the activity of Ni/TiO2-SAPO-11 catalyst, SAPO-11, the precursor was prepared by hydrothermal crystallization, and TiO2-SAPO-11 complex carrier was prepared by sol-gel method, then Ni/TiO2-SAPO-11 was produced by the final product. The catalytic performance of Ni/TiO2-SAPO-11 was studied in n-heptane isomerization, and the impact of catalyst preparation conditions on n-heptane isomerization was discussed in detail. The results showed that, with 20% of TiO2 composition, 2% of Ni capacity percentage and calcined temperature at 500°C, conversion of n-heptane and isomerization selectivity was up to 40.94% and 88.97% respectively.
基金supported by the Shandong Provincial Natural Science Foundation (No.ZR2022QB242)the National Natural Science Foundation of China (No.22306111 and 22306108)+1 种基金the Shandong Provincial Natural Science Foundation (No.ZR2020ZD20)the Chinese Postdoctoral Science Foundation (No.2023M732059).
文摘Mercury(Hg),especially methylmercury(MeHg),accumulation in rice grain due to rice paddy possessing conditions conducive to Hg methylation has led to human Hg exposure through consumption of rice-based daily meals.In addition to being a food staple,rice is widely used as a raw material to produce a vast variety of processed food products.Little is known about Hg levels in snacking rice-food products and potential Hg exposure from consumption of them,besides previous studies on infant rice cereals.Aiming to provide complementary information for a more complete assessment on Hg exposure risk originated from Hgcontaining rice,this study determined total Hg(THg)and MeHg levels in 195 rice-containing and rice-free processed food products covering all major types of snack foods marketed in China and the estimated daily intake(EDI)of dietary Hg from the consumption of these foods.The results clearly showed THg and MeHg contents in rice-containing foods were significantly higher than rice-free products,suggesting the transfer of Hg and MeHg from the rice to the end products,even after manufacturing processes.Moreover,significant positive correlations were observed between THg,MeHg,or MeHg/THg ratio and rice content for samples containing multiple grains as ingredients,further indicating the deciding role of rice for Hg levels in the end food products.Although the EDI of THg and MeHg via ricebased food products were relatively low compared to the reference dose,it should be considered these snacking food products would contribute additive Hg intake outside of the daily regular meals.
基金supported by the National Natural Science Foundation of China(T2288101,31971266,82272152,U1801252)Guangdong Basic and Applied Basic Research Foundation(2022A1515011925)+1 种基金Science and Technology Program of Guangzhou(202206040001)the Key Research and Development Program of Guangzhou(202007020002).
文摘Rheumatoid arthritis(RA)is a severe autoimmune disease with symptoms including synovial inflammation,cartilage erosion,and bone loss in RA lesions,which eventually lead to joint deformity and function loss.Most current treatments fail to achieve satisfying therapeutic outcomes with some adverse effects.Extracellular vesicles derived from apoptotic cells(apoEVs)have emerged as important mediators in intercellular communication regulating diverse physiological and pathological processes.In this study,we investigated the therapeutic efficacy of macrophage-derived and osteoclast-derived apoEVs(Mφ-apoEVs and OC-apoEVs)on RA.The in vitro results showed that both Mφ-apoEVs and OC-apoEVs induced macrophage repolarization toward the anti-inflammatory M2 phenotype,promoted chondrocyte functions and chondrogenesis,and inhibited osteoclast formation and maturation.In addition,OC-apoEVs promoted osteogenic differentiation.The in vivo study on the CIA mouse model further demonstrated that apoEVs could couple various functions and exert synergistic effects on the joint with RA,as evidenced by the regression of synovial inflammation,the reversal of cartilage damage and bone erosion,and the preservation of joint structure.These findings demonstrated that Mφ-apoEVs and OC-apoEVs contributed to restoring the homeostasis of the overall microenvironment in the RA joint and highlighted their potential application as a promising alternative to treat RA.
基金supported by the National Natural Science Foundation of China (Nos.22136006 and 51972302)the K.C.Wong Education Foundation of China (No.GJTD-2020-03)。
文摘The migration mechanisms,sources,and environmental risks of 29 legacy and emerging perfluorinated and polyfluoroalkyl species present in an oxidation pond(Ya'Er Lake)were investigated for treating sewage based on the analysis of their occurrence and distribution.The concentration of per-and polyfluoroalkyl substances(PFAS)in pond area was between0.30 and 63.2 ng/g dw(dry weight),with the overall average concentration of 8.00 ng/g dw.Notably,the PFAS concentrations in the surface sediments near the sewage outlet in Pond-1(50.2 ng/g dw)and Pond-5(average 15.1 ng/g dw)were 1–2 orders of magnitude higher than those in other areas.In general,the legacy PFAS,i.e.,perfluorooctane sulfonic acid was considered to be the major pollutant in the polluted area,on average,accounting for 73.0%of the total concentration of PFAS pollutants.By evaluating the regional distribution of different PFAS homologs,the short-chain PFAS pollutants with lower K_(ow)were found to migrate farther in both horizontal and vertical directions.The sewage outlets in Pond-1 and Pond-5are the main pollution sources in polluted area and the emerging PFAS pollutants in Pond-5have replaced the legacy PFAS pollutants as the main pollutants.Based on positive matrix factorization analysis,three main industrial sources of PFAS pollutants in the study area were identified:protective coating,fire-fighting,and food packaging sources.Moreover,the environmental risk assessment results showed that most study areas exhibited medium environmental risk(0.01≤Risk quotient(RQ)<1),indicating that the ecological environment risks in this area need further attention.
基金National Key Research and Development Program of China(2018YFA0703000)National Natural Science Foundation of China(22072047,U1801252)Science and Technology Program of Guangzhou(202007020002).
文摘The classical 3D-printed scaffolds have attracted enormous interests in bone regeneration due to the customized structural and mechanical adaptability to bone defects.However,the pristine scaffolds still suffer from the absence of dynamic and bioactive microenvironment that is analogous to natural extracellular matrix(ECM)to regulate cell behaviour and promote tissue regeneration.To address this challenge,we develop a black phosphorus nanosheets-enabled dynamic DNA hydrogel to integrate with 3D-printed scaffold to build a bioactive gel-scaffold construct to achieve enhanced angiogenesis and bone regeneration.The black phosphorus nanosheets reinforce the mechanical strength of dynamic self-healable hydrogel and endow the gel-scaffold construct with preserved protein binding to achieve sustainable delivery of growth factor.We further explore the effects of this activated construct on both human umbilical vein endothelial cells(HUVECs)and mesenchymal stem cells(MSCs)as well as in a critical-sized rat cranial defect model.The results confirm that the gel-scaffold construct is able to promote the growth of mature blood vessels as well as induce osteogenesis to promote new bone formation,indicating that the strategy of nano-enabled dynamic hydrogel integrated with 3D-printed scaffold holds great promise for bone tissue engineering.
基金The authors gratefully acknowledge funding from the Shenzhen Science and Technology Program(JCYJ20170815153105076,GJHZ20180411143347603)National Natural Science Foundation of China(31770107 and 21874116)+3 种基金Science and Technology Program of Guangdong Province(2019B010941002,2017B090911008)Guangdong Natural Science Funds for Distinguished Young Scholars(2016A030306018)Science and Technology Program of Guangzhou(201804020060,202007020002)Outstanding Scholar Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory(2018GZR110102001)。
文摘Bone is an important part of the human body structure and plays a vital role in human health.A microfluidic chip that can simulate the structure and function of bone will provide a platform for bone-related biomedical research.Hydroxyapatite(HA),a bioactive ceramic material,has a similar structure and composition to bone mineralization products.In this study,we used HA as a microfluidic chip component to provide a highly bionic bone environment.HA substrates with different microchannel structures were printed by using ceramic stereolithography(SLA)technology,and the minimum trench width was 50μm.The HA substrate with microchannels was sealed by a thin polydimethylsiloxane(PDMS)layer to make a HA-PDMS microfluidic chip.Cell culture experiments demonstrated that compared with PDMS,HA was more conducive to the proliferation and osteogenic differentiation of the human foetal osteoblast cell line(hFOB).In addition,the concentration gradient of the model drug doxorubicin hydrochloride(DOX)was successfully generated on a Christmas tree structure HA-PDMS chip,and the half maximal inhibitory concentration(IC50)of DOX was determined.The findings of this study indicate that the HA-PDMS microfluidic chip has great potential in the field of high-throughput bonerelated drug screening and bone-related research.
基金financially supported by the National key research and development plan(Grant No.2017YFC1105000,Grant No.2017YFA0205600)Outstanding Scholar Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory(2018GZR110102001)+4 种基金the Science and Technology Program of Guangdong Province(Grant No.2019B010941002)the Science and Technology Program of Guangzhou(Grant No.201804020060,Grant No.202007020002)Natural Science Foundation of Guangdong Province(Grant No.2021A1515011741,2020A1515011354)the National Nature Science Foundation of China(Grants U1801252),National Natural Science Foundation of China(31700823)Guangzhou Science and Technology Planning Project(202102020005).
文摘Calcium phosphate bio-ceramics are osteo-conductive,but it remains a challenge to promote the induction of bone augmentation and capillary formation.The surface micro/nano-topography of materials can be recognized by cells and then the cell fate are mediated.Traditional regulation methods of carving surface structures on bio-ceramics employ mineral reagents and organic additives,which might introduce impurity phases and affect the biological results.In a previous study,a facile and novel method was utilized with ultrapure water as the unique reagent for hydrothermal treatment,and a uniform hydroxyapatite(HAp)surface layer was constructed on composite ceramics(β-TCP/CaSiO_(3))in situ.Further combined with 3D printing technology,biomimetic hierarchical structure scaffolds were fabricated with interconnected porous composite ceramic scaffolds as the architecture and micro/nano-rod hybrid HAp as the surface layer.The obtained HAp surface layer favoured cell adhesion,alleviated the cytotoxicity of precursor scaffolds,and upregulated the cellular differentiation of mBMSCs and gene expression of HUVECs in vitro.In vivo studies showed that capillary formation,bone augmentation and new bone matrix formation were upregulated after the HAp surface layer was obtained,and the results confirmed that the fabricated biomimetic hierarchical structure scaffold could be an effective candidate for bone regeneration.
基金support from the National key research and development plan(Grant No.2021YFB3800800)the National Natural Science Foundation of China(52172281)+7 种基金Natural Science Foundation of Guangdong Province(Grant No.2021A1515011741&No.2020A1515011354)the Science and Technology Program of Guangdong Province(Grant No.2019B010941002)the Science and Technology Program of Guangzhou(Grant No.202007020002&No.202206040001)the financial support from the National Natural Science Foundation of China(Grant No.52002132)China Postdoctoral Science Foundation(2019M662925)J.D.acknowledges the financial support from Guangzhou Science and Technology Planning Project(202102020005)National Natural Science Foundation of China(Grant No.32201089)Guangdong Science and Technology Planning Project(2022A1515010608).
文摘Bone bionics and structural engineering have sparked a broad interest in optimizing artificial scaffolds for better bone regeneration.However,the mechanism behind scaffold pore morphology-regulated bone regeneration remains unclear,making the structure design of scaffolds for bone repair challenging.To address this issue,we have carefully assessed diverse cell behaviors of bone mesenchymal stem cells(BMSCs)on theβ-tricalcium phosphate(β-TCP)scaffolds with three representative pore morphologies(i.e.,cross column,diamond,and gyroid pore unit,respectively).Among the scaffolds,BMSCs on theβ-TCP scaffold with diamond pore unit(designated as D-scaffold)demonstrated enhanced cytoskeletal forces,elongated nucleus,faster cell mobility,and better osteogenic differentiation potential(for example,the alkaline phosphatase expression level in D-scaffold were 1.5-2 times higher than other groups).RNA-sequencing analysis and signaling pathway intervention revealed that Ras homolog gene family A(RhoA)/Rho-associated kinase-2(ROCK2)has in-depth participated in the pore morphology-mediated BMSCs behaviors,indicating an important role of mechanical signaling transduction in scaffold-cell interactions.Finally,femoral condyle defect repair results showed that D-scaffold could effectively promote endogenous bone regeneration,of which the osteogenesis rate was 1.2-1.8 times higher than the other groups.Overall,this work provides insights into pore morphology-mediated bone regeneration mechanisms for developing novel bioadaptive scaffold designs.
