Background&Objective Knee osteoarthritis(OA)is a degenerative disease,which not only induces superficial cartilage defects and full-thickness cartilage defects,but also exacerbates the microenvironment of the knee...Background&Objective Knee osteoarthritis(OA)is a degenerative disease,which not only induces superficial cartilage defects and full-thickness cartilage defects,but also exacerbates the microenvironment of the knee joint and affects the mechano-chemical responses of the organ.As a growth/repair factor,mechanical growth factor(MGF)has the function of preventing OA,promoting cartilage regeneration and repairing damaged ligaments.activating transcription factor 2(ATF-2),a transcription factor,has the property of binding to cytokines,which makes it involved in the transcriptional regulation of various pathways in response to cellular stress,inflammatory cytokine and growth factors.At present,little is known about the effect of MGF on human osteoarthritis ligament fibroblasts(OA-LFs),and whether the approach can promote OA-LFs timely response to the mechanical injury and initiate signaling pathway for cell survival.Therefore,the purpose of this study is to investigate whether MGF promotes mechanical response to ligament fibroblasts in osteoarthritis knee cavity via ATF-2.Methods OA-LFs were seeded onto six-cell BioFlex plates and suffered from 12%static mechanical stretch[60 cycles/minute(1 Hz)]for 12 hours to mimic mechanical force mediated ligament injury.Meanwhile,OA-LFs were treated with MGF before and during mechanical stretch.Intracellular reactive oxygen species(ROS)and GRP78 mRNA expression were investigated to detect the cellular stress response of OA-LFs.The scratch test was performed to detect the migration ability of cells,gelatin zymography was used to examine the effect of MGF on the activity of matrix metalloproteinase 2(MMP-2)in OA-LFs,and cell deformation was detected by phalloidin-FITC staining after stretching.Quantitative real-time polymerase chain reaction(qRT-PCR)was used to screen the messenger RNA(mRNA)expression of ATF family members after OALFs treatment with MGF.Western blotting further proved that MGF is capable to activate the p-ATF-2.Results OA delays LFs response to mechanical injury,while MGF pretreatment can promote cells timely feedback the mechanically stimuli by inducing cellular stress.MGF treatment can alleviate the decline in cell migration ability caused by mechanical injury and further promote cell migration.In addition,MGF can reduce the activity of MM P-5 and alleviate the stretch-induced deformation of OA-LFs.Furthermore,the mRNA expression of ATF-2 up-regulated in a dose-dependent manner upon MGF treatment compared with control,while the expression of ATF-5 gene was down-regulated in a dose-dependent.Protein levels showed that the expression of p-ATF-2 increased with increasing MGF concentration.Conclusions Our study shows that MGF pretreatment of OA-LFs can respond quickly to mechanical damage and accelerate the ligament injury repair by promoting cell migration,decreasing the MMP-2 activity,and remitting the cell deformation.Therefore,MGF has potential as a therapeutic for OA patients.展开更多
The presence of excessive reactive oxygen species(ROS)after injuries to the enthesis could lead to cellular oxidative damage,high inflammatory response,chronic inflammation,and limited fibrochondral inductivity,making...The presence of excessive reactive oxygen species(ROS)after injuries to the enthesis could lead to cellular oxidative damage,high inflammatory response,chronic inflammation,and limited fibrochondral inductivity,making tissue repair and functional recovery difficult.Here,a multifunctional silk fibroin nanofiber modified with polydopamine and kartogenin was designed and fabricated to not only effectively reduce inflammation by scavenging ROS in the early stage of the enthesis healing but also enhance fibrocartilage formation with fibrochondrogenic induction in the later stages.The in vitro results confirmed the antioxidant capability and the fibrochondral inductivity of the functionalized nanofibers.In vivo studies showed that the multifunctional nanofiber can significantly improve the integration of tendon-bone and accelerate the regeneration of interface tissue,resulting in an excellent biomechanical property.Thus,the incorporation of antioxidant and bio-active molecules into extracellular matrix-like biomaterials in interface tissue engineering provides an integrative approach that facilitates damaged tissue regeneration and functional recovery,thereby improving the clinical outcome of the engineered tissue.展开更多
Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the...Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.展开更多
Recovering the low-rank structure of data matrix from sparse errors arises in the principal component pursuit （PCP）. This paper exploits the higher-order generalization of matrix recovery, named higher-order princip...Recovering the low-rank structure of data matrix from sparse errors arises in the principal component pursuit （PCP）. This paper exploits the higher-order generalization of matrix recovery, named higher-order principal component pursuit （HOPCP）, since it is critical in multi-way data analysis. Unlike the convexification （nuclear norm） for matrix rank function, the tensorial nuclear norm is stil an open problem. While existing preliminary works on the tensor completion field provide a viable way to indicate the low complexity estimate of tensor, therefore, the paper focuses on the low multi-linear rank tensor and adopt its convex relaxation to formulate the convex optimization model of HOPCP. The paper further propose two algorithms for HOPCP based on alternative minimization scheme： the augmented Lagrangian alternating direction method （ALADM） and its truncated higher-order singular value decomposition （ALADM-THOSVD） version. The former can obtain a high accuracy solution while the latter is more efficient to handle the computationally intractable problems. Experimental results on both synthetic data and real magnetic resonance imaging data show the applicability of our algorithms in high-dimensional tensor data processing.展开更多
Erythrocyte membrane(EM)-camouflaged chemotherapeutic delivery nanovehicles hold promise for solid tumor therapy because of their excellent biostability and biocompatibility. However, it is accompanied with insufficie...Erythrocyte membrane(EM)-camouflaged chemotherapeutic delivery nanovehicles hold promise for solid tumor therapy because of their excellent biostability and biocompatibility. However, it is accompanied with insufficient targeting effect and deficient pharmacokinetic behavior due to the lack of a regulated biointerface to navigate and overcome biological transportation obstacles in solid tumor therapy.Herein, an anti-epidermal growth factor receptor(EGFR) aptamer(EApt) modified and EM-cloaked chemotherapeutic nanomissile delivery system was constructed. The anchored-EApt acting as a specific EGFR suppressor promotes to inhibit the overexpression of EGFR and initiate the cell apoptosis. Importantly, the resulting PLGA-DOX@EM-EApt orchestrated the bioactivity of each component and provided synergistic cell apoptosis and antitumor effects by precisely suppressing EGFR expression levels and delivering DOX. The in vitro and in vivo experimental results confirmed that the immune escape and active targeting behaviors of PLGA-DOX@EM-EApt could significantly promote its drug retention and tumor inhibition abilities. Our findings propose a novel strategy using the biointerface functionalization technique, demonstrating a promising therapeutic platform via a biomimetic drug delivery system for precise solid tumor recognition and synergistic therapy.展开更多
In this paper,modified membranes containingβ-cyclodextrin(β-CD)and heparin coatings were prepared on the surface of poly-4-methyl-1-pentene(PMP)hollow fibrous membrane using the high strength adhesion of polydopamin...In this paper,modified membranes containingβ-cyclodextrin(β-CD)and heparin coatings were prepared on the surface of poly-4-methyl-1-pentene(PMP)hollow fibrous membrane using the high strength adhesion of polydopamine(PDA).In this paper,β-CD was added to increase the hemocompatibility of the PMP hollow fibrous membranes and the stability of the heparin coating.The uniformity of the heparin coating withβ-CD addition was better than that of the groups withoutβ-CD.After seven days of saline rinsing,the surface of the modified membranes withβ-CD addition still had a large amount of heparin present,which was more stable compared to the control group.After surface modification,the modified membrane changed from hydrophobic to hydrophilic.Importantly,the protein adsorption,platelet adhesion,and hemolysis rates of the modified membranes were significantly reduced compared with the pristine membranes.The APTT values were also significantly increased.The results showed that the modified membranes with the addition ofβ-CD had better hydrophilicity,can maintain the stability of heparin coating for a long time,and finally showed good hemocompatibility.展开更多
Orthodontic forces can cause stress and strain concentration and microcracks on tooth root surfaces.This study aimed to analyze whether a lingual orthodontic appliance was more likely to cause root stress concentratio...Orthodontic forces can cause stress and strain concentration and microcracks on tooth root surfaces.This study aimed to analyze whether a lingual orthodontic appliance was more likely to cause root stress concentration and root resorption than the traditional buccal appliance.A finite element model of the root of the maxillary central incisor with straight,buccal,and lingual curvatures was established.A load perpendicular to the tooth surface on the buccal and lingual surfaces of the central incisor was applied,and the stress and strain concentration at the root apex was compared.The stress and strain at the root apex of the lingual cingulum group were lesser than those of the buccal group;little difference was observed between the lingual and buccal clinical crown central augmentation groups.The stress and strain at the root apex of the lingual direction movement group were greater than those of the buccal direction movement group.The direction of the root curvature also influenced the amount of stress and strain at the root apex.The difference in the risk of root resorption between lingual and buccal orthodontics is dependent on the height of the bracket placement.The loading direction of the orthodontic force and direction of the root curvature also affect the stress and strain at the root apex.展开更多
Moving target detection is one of the most basic tasks in computer vision.In conventional wisdom,the problem is solved by iterative optimization under either Matrix Decomposition(MD)or Matrix Factorization(MF)framewor...Moving target detection is one of the most basic tasks in computer vision.In conventional wisdom,the problem is solved by iterative optimization under either Matrix Decomposition(MD)or Matrix Factorization(MF)framework.MD utilizes foreground information to facilitate background recovery.MF uses noise-based weights to fine-tune the background.So both noise and foreground information contribute to the recovery of the background.To jointly exploit their advantages,inspired by two framework complementary characteristics,we propose to simultaneously exploit the advantages of these two optimizing approaches in a unified framework called Joint Matrix Decomposition and Factorization(JMDF).To improve background extraction,a fuzzy factorization is designed.The fuzzy membership of the background/foreground association is calculated during the factorization process to distinguish their contributions of both to background estimation.To describe the spatio-temporal continuity of foreground more accurately,we propose to incorporate the first order temporal difference into the group sparsity constraint adaptively.The temporal constraint is adjusted adaptively.Both foreground and the background are jointly estimated through an effective alternate optimization process,and the noise can be modeled with the specific probability distribution.The experimental results of vast real videos illustrate the effectiveness of our method.Compared with the current state-of-the-art technology,our method can usually form the clearer background and extract the more accurate foreground.Anti-noise experiments show the noise robustness of our method.展开更多
The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enh...The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enhance the in vivo circulation and retention time of micro/nanodrug carriers,provide targeted drug delivery effects,and neutralize bacterial toxins.Notably,recent studies have successfully coated various types of cell membranes onto the surfaces of macroscopic materials,such as electrospun fiber scaffolds and decellularized matrices,to promote tissue repair,modulate host responses to foreign materials,and alleviate inflammation.This review comprehensively summarizes the latest research progress in the modification of macroscopic biomaterials with cell membranes.The insights provided aim to serve as a valuable reference for the preparation of cell membrane biomimetic coatings and their applications in the field of tissue repair.展开更多
The implantation of synthetic polymeric scaffolds induced foreign-body reaction(FBR)seriously influence the wound healing and impair functionality recovery.A novel short peptide,mechano-growth factor(MGF),was introduc...The implantation of synthetic polymeric scaffolds induced foreign-body reaction(FBR)seriously influence the wound healing and impair functionality recovery.A novel short peptide,mechano-growth factor(MGF),was introduced in this study to modify an electrospun polycaprolactone(PCL)fibrous scaffold to direct the macrophage phenotype transition and mitigate the FBR.In vitro studies discovered the cell signal transduction mechanism of MGF regulates the macrophage polarization via the expression of related genes and proteins.We found that macrophages response the MGF stimuli via endocytosis,then MGF promotes the histone acetylation and upregulates the STAT6 expression to direct an anti-inflammatory phenotype transition.Subsequently,an immunoregulatory electrospun PCL fibrous scaffold was modified by silk fibroin(SF)single-component layer-by-layer assembly,and the SF was decorated with MGF via click chemistry.Macrophages seeded on scaffold to identify the function of MGF modified scaffold in directing macrophage polarization in vitro.Parallelly,rat subcutaneous implantation model and rat tendon adhesion model were performed to detect the immunomodulatory ability of the MGF-modified scaffold in vivo.The results demonstrate that MGF-modified scaffold is beneficial to the transformation of macrophages to M2 phenotype in vitro.More importantly,MGF-functionalized scaffold can inhibit the FBR at the subcutaneous tissue and prevent tissue adhesion.展开更多
Product quantization is now considered as an effective approach to solve the approximate nearest neighbor(ANN)search.A collection of derivative algorithms have been developed.However,the current techniques ignore the ...Product quantization is now considered as an effective approach to solve the approximate nearest neighbor(ANN)search.A collection of derivative algorithms have been developed.However,the current techniques ignore the intrinsic high order structures of data,which usually contain helpful information for improving the computational precision.In this paper,aiming at the complex structure of high order data,we design an optimized technique,called optimized high order product quantization(O-HOPQ)for ANN search.In O-HOPQ,we incorporate the high order structures of the data into the process of designing a more effective subspace decomposition way.As a result,spatial adjacent elements in the high order data space are grouped into the same subspace.Then,O-HOPQ generates its spatial structured codebook,by optimizing the quantization distortion.Starting from the structured codebook,the global optimum quantizers can be obtained effectively and efficiently.Experimental results show that appropriate utilization of the potential information that exists in the complex structure of high order data will result in significant improvements to the performance of the product quantizers.Besides,the high order structure based approaches are effective to the scenario where the data have intrinsic complex structures.展开更多
The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the bra...The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the braiding of scaffolds can offer a tunable platform for fabricating vascular grafts,the effects of braided silk fiber skeletons on the porosity,remodeling,and patency in vivo have not been thoroughly investigated.展开更多
基金supported by the National Natural Science Foundation of China ( 11532004,31270990, 31600762)Innovation and Attracting Talents Program for College and University( “111”Project) ( B06023)
文摘Background&Objective Knee osteoarthritis(OA)is a degenerative disease,which not only induces superficial cartilage defects and full-thickness cartilage defects,but also exacerbates the microenvironment of the knee joint and affects the mechano-chemical responses of the organ.As a growth/repair factor,mechanical growth factor(MGF)has the function of preventing OA,promoting cartilage regeneration and repairing damaged ligaments.activating transcription factor 2(ATF-2),a transcription factor,has the property of binding to cytokines,which makes it involved in the transcriptional regulation of various pathways in response to cellular stress,inflammatory cytokine and growth factors.At present,little is known about the effect of MGF on human osteoarthritis ligament fibroblasts(OA-LFs),and whether the approach can promote OA-LFs timely response to the mechanical injury and initiate signaling pathway for cell survival.Therefore,the purpose of this study is to investigate whether MGF promotes mechanical response to ligament fibroblasts in osteoarthritis knee cavity via ATF-2.Methods OA-LFs were seeded onto six-cell BioFlex plates and suffered from 12%static mechanical stretch[60 cycles/minute(1 Hz)]for 12 hours to mimic mechanical force mediated ligament injury.Meanwhile,OA-LFs were treated with MGF before and during mechanical stretch.Intracellular reactive oxygen species(ROS)and GRP78 mRNA expression were investigated to detect the cellular stress response of OA-LFs.The scratch test was performed to detect the migration ability of cells,gelatin zymography was used to examine the effect of MGF on the activity of matrix metalloproteinase 2(MMP-2)in OA-LFs,and cell deformation was detected by phalloidin-FITC staining after stretching.Quantitative real-time polymerase chain reaction(qRT-PCR)was used to screen the messenger RNA(mRNA)expression of ATF family members after OALFs treatment with MGF.Western blotting further proved that MGF is capable to activate the p-ATF-2.Results OA delays LFs response to mechanical injury,while MGF pretreatment can promote cells timely feedback the mechanically stimuli by inducing cellular stress.MGF treatment can alleviate the decline in cell migration ability caused by mechanical injury and further promote cell migration.In addition,MGF can reduce the activity of MM P-5 and alleviate the stretch-induced deformation of OA-LFs.Furthermore,the mRNA expression of ATF-2 up-regulated in a dose-dependent manner upon MGF treatment compared with control,while the expression of ATF-5 gene was down-regulated in a dose-dependent.Protein levels showed that the expression of p-ATF-2 increased with increasing MGF concentration.Conclusions Our study shows that MGF pretreatment of OA-LFs can respond quickly to mechanical damage and accelerate the ligament injury repair by promoting cell migration,decreasing the MMP-2 activity,and remitting the cell deformation.Therefore,MGF has potential as a therapeutic for OA patients.
基金supported financially by the National Natural Science Foundation of China[No.11532004,11832008]Innovation and Attracting Talents Program for College and University(“111”Project)[No.B06023]。
文摘The presence of excessive reactive oxygen species(ROS)after injuries to the enthesis could lead to cellular oxidative damage,high inflammatory response,chronic inflammation,and limited fibrochondral inductivity,making tissue repair and functional recovery difficult.Here,a multifunctional silk fibroin nanofiber modified with polydopamine and kartogenin was designed and fabricated to not only effectively reduce inflammation by scavenging ROS in the early stage of the enthesis healing but also enhance fibrocartilage formation with fibrochondrogenic induction in the later stages.The in vitro results confirmed the antioxidant capability and the fibrochondral inductivity of the functionalized nanofibers.In vivo studies showed that the multifunctional nanofiber can significantly improve the integration of tendon-bone and accelerate the regeneration of interface tissue,resulting in an excellent biomechanical property.Thus,the incorporation of antioxidant and bio-active molecules into extracellular matrix-like biomaterials in interface tissue engineering provides an integrative approach that facilitates damaged tissue regeneration and functional recovery,thereby improving the clinical outcome of the engineered tissue.
基金This work was financially supported by Innovation Capability Support Program of Shaanxi(2020KJXX082)the Foundation(202005)of Tianjin Key Laboratory of Pulp&Paper(Tianjin University of Science&Technology).
文摘Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.
基金supported by the National Natural Science Foundationof China(51275348)
文摘Recovering the low-rank structure of data matrix from sparse errors arises in the principal component pursuit （PCP）. This paper exploits the higher-order generalization of matrix recovery, named higher-order principal component pursuit （HOPCP）, since it is critical in multi-way data analysis. Unlike the convexification （nuclear norm） for matrix rank function, the tensorial nuclear norm is stil an open problem. While existing preliminary works on the tensor completion field provide a viable way to indicate the low complexity estimate of tensor, therefore, the paper focuses on the low multi-linear rank tensor and adopt its convex relaxation to formulate the convex optimization model of HOPCP. The paper further propose two algorithms for HOPCP based on alternative minimization scheme： the augmented Lagrangian alternating direction method （ALADM） and its truncated higher-order singular value decomposition （ALADM-THOSVD） version. The former can obtain a high accuracy solution while the latter is more efficient to handle the computationally intractable problems. Experimental results on both synthetic data and real magnetic resonance imaging data show the applicability of our algorithms in high-dimensional tensor data processing.
基金supported by the National Natural Science Foundation of China (Nos. 82073807 and 81973277)the WorldClass Universities (Disciplines)the Characteristic Development Guidance Funds for the Central Universities,China (No. PY3A012)。
文摘Erythrocyte membrane(EM)-camouflaged chemotherapeutic delivery nanovehicles hold promise for solid tumor therapy because of their excellent biostability and biocompatibility. However, it is accompanied with insufficient targeting effect and deficient pharmacokinetic behavior due to the lack of a regulated biointerface to navigate and overcome biological transportation obstacles in solid tumor therapy.Herein, an anti-epidermal growth factor receptor(EGFR) aptamer(EApt) modified and EM-cloaked chemotherapeutic nanomissile delivery system was constructed. The anchored-EApt acting as a specific EGFR suppressor promotes to inhibit the overexpression of EGFR and initiate the cell apoptosis. Importantly, the resulting PLGA-DOX@EM-EApt orchestrated the bioactivity of each component and provided synergistic cell apoptosis and antitumor effects by precisely suppressing EGFR expression levels and delivering DOX. The in vitro and in vivo experimental results confirmed that the immune escape and active targeting behaviors of PLGA-DOX@EM-EApt could significantly promote its drug retention and tumor inhibition abilities. Our findings propose a novel strategy using the biointerface functionalization technique, demonstrating a promising therapeutic platform via a biomimetic drug delivery system for precise solid tumor recognition and synergistic therapy.
基金This research was supported by National Key R&D Program of China(2020YFC0862903)the National Natural Science Foundation of China(22078146)+1 种基金the Key R&D program of Jiangsu Province(BE2021022)The Natural Science Foundation of Jiangsu Province(BK20200091).
文摘In this paper,modified membranes containingβ-cyclodextrin(β-CD)and heparin coatings were prepared on the surface of poly-4-methyl-1-pentene(PMP)hollow fibrous membrane using the high strength adhesion of polydopamine(PDA).In this paper,β-CD was added to increase the hemocompatibility of the PMP hollow fibrous membranes and the stability of the heparin coating.The uniformity of the heparin coating withβ-CD addition was better than that of the groups withoutβ-CD.After seven days of saline rinsing,the surface of the modified membranes withβ-CD addition still had a large amount of heparin present,which was more stable compared to the control group.After surface modification,the modified membrane changed from hydrophobic to hydrophilic.Importantly,the protein adsorption,platelet adhesion,and hemolysis rates of the modified membranes were significantly reduced compared with the pristine membranes.The APTT values were also significantly increased.The results showed that the modified membranes with the addition ofβ-CD had better hydrophilicity,can maintain the stability of heparin coating for a long time,and finally showed good hemocompatibility.
基金This work was supported by the National Natural Science Foundation of China(No.U20A20390 and 11827803).
文摘Orthodontic forces can cause stress and strain concentration and microcracks on tooth root surfaces.This study aimed to analyze whether a lingual orthodontic appliance was more likely to cause root stress concentration and root resorption than the traditional buccal appliance.A finite element model of the root of the maxillary central incisor with straight,buccal,and lingual curvatures was established.A load perpendicular to the tooth surface on the buccal and lingual surfaces of the central incisor was applied,and the stress and strain concentration at the root apex was compared.The stress and strain at the root apex of the lingual cingulum group were lesser than those of the buccal group;little difference was observed between the lingual and buccal clinical crown central augmentation groups.The stress and strain at the root apex of the lingual direction movement group were greater than those of the buccal direction movement group.The direction of the root curvature also influenced the amount of stress and strain at the root apex.The difference in the risk of root resorption between lingual and buccal orthodontics is dependent on the height of the bracket placement.The loading direction of the orthodontic force and direction of the root curvature also affect the stress and strain at the root apex.
基金supported in part by the National Natural Science Foundation of China (Grant No.61902106)in part by the Natural Science Foundation of Hebei Province (No.F2020202028).
文摘Moving target detection is one of the most basic tasks in computer vision.In conventional wisdom,the problem is solved by iterative optimization under either Matrix Decomposition(MD)or Matrix Factorization(MF)framework.MD utilizes foreground information to facilitate background recovery.MF uses noise-based weights to fine-tune the background.So both noise and foreground information contribute to the recovery of the background.To jointly exploit their advantages,inspired by two framework complementary characteristics,we propose to simultaneously exploit the advantages of these two optimizing approaches in a unified framework called Joint Matrix Decomposition and Factorization(JMDF).To improve background extraction,a fuzzy factorization is designed.The fuzzy membership of the background/foreground association is calculated during the factorization process to distinguish their contributions of both to background estimation.To describe the spatio-temporal continuity of foreground more accurately,we propose to incorporate the first order temporal difference into the group sparsity constraint adaptively.The temporal constraint is adjusted adaptively.Both foreground and the background are jointly estimated through an effective alternate optimization process,and the noise can be modeled with the specific probability distribution.The experimental results of vast real videos illustrate the effectiveness of our method.Compared with the current state-of-the-art technology,our method can usually form the clearer background and extract the more accurate foreground.Anti-noise experiments show the noise robustness of our method.
基金National Natural Science Foundation of China(grant number 31971258,32371405).
文摘The cell membranes,derived from natural sources,possesses unique physicochemical properties of phospholipid bilayers and biological functionalities of membrane proteins.This makes it an ideal biomimetic coating to enhance the in vivo circulation and retention time of micro/nanodrug carriers,provide targeted drug delivery effects,and neutralize bacterial toxins.Notably,recent studies have successfully coated various types of cell membranes onto the surfaces of macroscopic materials,such as electrospun fiber scaffolds and decellularized matrices,to promote tissue repair,modulate host responses to foreign materials,and alleviate inflammation.This review comprehensively summarizes the latest research progress in the modification of macroscopic biomaterials with cell membranes.The insights provided aim to serve as a valuable reference for the preparation of cell membrane biomimetic coatings and their applications in the field of tissue repair.
基金We acknowledge the funding support from the National Natural Science Foundation of China(31971258,11532004)the 111 Project(B06023,B13003)Chongqing Postdoctoral Science Foundation(csts2019jcyj-bsh0068).
文摘The implantation of synthetic polymeric scaffolds induced foreign-body reaction(FBR)seriously influence the wound healing and impair functionality recovery.A novel short peptide,mechano-growth factor(MGF),was introduced in this study to modify an electrospun polycaprolactone(PCL)fibrous scaffold to direct the macrophage phenotype transition and mitigate the FBR.In vitro studies discovered the cell signal transduction mechanism of MGF regulates the macrophage polarization via the expression of related genes and proteins.We found that macrophages response the MGF stimuli via endocytosis,then MGF promotes the histone acetylation and upregulates the STAT6 expression to direct an anti-inflammatory phenotype transition.Subsequently,an immunoregulatory electrospun PCL fibrous scaffold was modified by silk fibroin(SF)single-component layer-by-layer assembly,and the SF was decorated with MGF via click chemistry.Macrophages seeded on scaffold to identify the function of MGF modified scaffold in directing macrophage polarization in vitro.Parallelly,rat subcutaneous implantation model and rat tendon adhesion model were performed to detect the immunomodulatory ability of the MGF-modified scaffold in vivo.The results demonstrate that MGF-modified scaffold is beneficial to the transformation of macrophages to M2 phenotype in vitro.More importantly,MGF-functionalized scaffold can inhibit the FBR at the subcutaneous tissue and prevent tissue adhesion.
基金the National Natural Science Foundation of China(Grant No.61732011)Applied Fundamental Research Program of Qinghai Province(2019-ZJ-7017).
文摘Product quantization is now considered as an effective approach to solve the approximate nearest neighbor(ANN)search.A collection of derivative algorithms have been developed.However,the current techniques ignore the intrinsic high order structures of data,which usually contain helpful information for improving the computational precision.In this paper,aiming at the complex structure of high order data,we design an optimized technique,called optimized high order product quantization(O-HOPQ)for ANN search.In O-HOPQ,we incorporate the high order structures of the data into the process of designing a more effective subspace decomposition way.As a result,spatial adjacent elements in the high order data space are grouped into the same subspace.Then,O-HOPQ generates its spatial structured codebook,by optimizing the quantization distortion.Starting from the structured codebook,the global optimum quantizers can be obtained effectively and efficiently.Experimental results show that appropriate utilization of the potential information that exists in the complex structure of high order data will result in significant improvements to the performance of the product quantizers.Besides,the high order structure based approaches are effective to the scenario where the data have intrinsic complex structures.
基金The authors graciously acknowledge professor Deling Kong's lab for their assistance with the animal experiments.This project was supported by the National Natural Science Foundation of China(T2288101,32000968,32071359,11827803,and U20A20390)Beijing Natural Science Foundation(M22026)Fundamental Research Funds for the Central Universities,and 111 Project(B13003).
文摘The development of small-diameter vascular grafts that can meet the long-term patency required for implementation in clinical practice presents a key challenge to the research field.Although techniques such as the braiding of scaffolds can offer a tunable platform for fabricating vascular grafts,the effects of braided silk fiber skeletons on the porosity,remodeling,and patency in vivo have not been thoroughly investigated.
