Mesenchymal stem cells(MSCs)are stem/progenitor cells capable of self-renewal and differentiation into osteoblasts,chondrocytes and adipocytes.The transformation of multipotent MSCs to adipocytes mainly involves two s...Mesenchymal stem cells(MSCs)are stem/progenitor cells capable of self-renewal and differentiation into osteoblasts,chondrocytes and adipocytes.The transformation of multipotent MSCs to adipocytes mainly involves two subsequent steps from MSCs to preadipocytes and further preadipocytes into adipocytes,in which the process MSCs are precisely controlled to commit to the adipogenic lineage and then mature into adipocytes.Previous studies have shown that the master transcription factors C/enhancer-binding protein alpha and peroxisome proliferation activator receptor gamma play vital roles in adipogenesis.However,the mechanism underlying the adipogenic differentiation of MSCs is not fully understood.Here,the current knowledge of adipogenic differentiation in MSCs is reviewed,focusing on signaling pathways,noncoding RNAs and epigenetic effects on DNA methylation and acetylation during MSC differentiation.Finally,the relationship between maladipogenic differentiation and diseases is briefly discussed.We hope that this review can broaden and deepen our understanding of how MSCs turn into adipocytes.展开更多
Current electro spun membranes used for pulp capping still lack the sustained-release capability and long-term anti-inflammatory effects that are favorable for dental pulp regeneration.In this work,a single-layered po...Current electro spun membranes used for pulp capping still lack the sustained-release capability and long-term anti-inflammatory effects that are favorable for dental pulp regeneration.In this work,a single-layered poly(lac tic acid)(PLA)electro spun membrane loaded with amorphous calcium phosphate(ACP)and aspirin(PLA/ACP/Aspirin membrane,i.e.,PA A membrane)is sandwiched between two poly(lactic-co-glycolic acid)(PLGA)electro spun membranes as a novel sandwich-structured PLGA and PA A composite electro spun membrane(PLGA-PAA membrane)to resolve the need for sustained-release design and anti-inflammatory effects.Contact angle measurements indicate that the PLGA-PAA membrane is more hydrophilic than the PAA membrane.An in vitro release study reveals that PLGA membranes coated on PAA membrane could slightly slow down ion release,while signiificantly prolonging aspirin release.We also co-cultured membranes with dental pulp stem cells(DPSCs)and human monocytic THP-1 cells to evaluate their osteogenic ability and anti-inflammatory effects,respectively.Compared with the PAA membrane,the PLGA-PAA membrane promotes cell adhesion,proliferation,and osteogenic differentiation.A prolonged anti-inflammatory effect of up to 18 days is also observed in the PLGA-PAA group.The results suggest a promising strategy for fabricating an electro spun membrane system with controlled release capabilities and long-term anti-inflammatory effects for use as pulp-capping material for regeneration of the dentin-pulp complex.展开更多
This work presents a trajectory tracking control method for snake robots.This method eliminates the influence of time-varying interferences on the body and reduces the offset error of a robot with a predetermined traj...This work presents a trajectory tracking control method for snake robots.This method eliminates the influence of time-varying interferences on the body and reduces the offset error of a robot with a predetermined trajectory.The optimized line-of-sight(LOS)guidance strategy drives the robot’s steering angle to maintain its anti-sideslip ability by predicting position errors and interferences.Then,the predictions of system parameters and viscous friction coefficients can compensate for the joint torque control input.The compensation is adopted to enhance the compatibility of a robot within ever-changing environments.Simulation and experimental outcomes show that our work can decrease the fluctuation peak of the tracking errors,reduce adjustment time,and improve accuracy.展开更多
Bone tissue engineering is an exciting approach to directly repair bone defects or engineer bone tissue for transplantation.Biomaterials play a pivotal role in providing a template and extracellular environment to sup...Bone tissue engineering is an exciting approach to directly repair bone defects or engineer bone tissue for transplantation.Biomaterials play a pivotal role in providing a template and extracellular environment to support regenerative cells and promote tissue regeneration. A variety of signaling cues have been identified to regulate cellular activity, tissue development, and the healing process. Numerous studies and trials have shown the promise of tissue engineering, but successful translations of bone tissue engineering research into clinical applications have been limited, due in part to a lack of optimal delivery systems for these signals. Biomedical engineers are therefore highly motivated to develop biomimetic drug delivery systems, which benefit from mimicking signaling molecule release or presentation by the native extracellular matrix during development or the natural healing process. Engineered biomimetic drug delivery systems aim to provide control over the location, timing, and release kinetics of the signal molecules according to the drug's physiochemical properties and specific biological mechanisms. This article reviews biomimetic strategies in signaling delivery for bone tissue engineering, with a focus on delivery systems rather than specific molecules. Both fundamental considerations and specific design strategies are discussed with examples of recent research progress, demonstrating the significance and potential of biomimetic delivery systems for bone tissue engineering.展开更多
This study aims to investigate the regional variations of trabecular morphological parameters and mechanical parameters of the femoral head,as well as to determine the relationship between trabecular morphological and...This study aims to investigate the regional variations of trabecular morphological parameters and mechanical parameters of the femoral head,as well as to determine the relationship between trabecular morphological and mechanical parameters.Seven femoral heads from patients with fractured proximal femur were scanned using a micro-CT system.Each femoral head was divided into 12 sub-regions according to the trabecular orientation.One 125 mm^3 trabecular cubic model was reconstructed from each sub-region.A total of 81 trabecular models were reconstructed,except three destroyed sub-regions from two femoral heads during the surgery.Trabecular morphological parameters,i.e.trabecular separation(Tb.Sp),trabecular thickness(Tb.Th),specific bone surface(BS/B V),bone volume fraction(BV/TV),structural model index(SMI),and degree of anisotropy(DA) were measured.Micro-finite element analyses were performed for each cube to obtain the apparent Young's modulus and tissue level von Mises stress distribution under 1%compressive strain along three orthogonal directions,respectively.Results revealed significant regional variations in the morphological parameters(P〈0.05).Young's moduli along the trabecular orientation were significantly higher than those along the other two directions.In general,trabecular mechanical properties in the medial region were lower than those in the lateral region.Trabecular mechanical parameters along the trabecular orientation were significantly correlated with BS/BV,BV/TV,Tb.Th,and DA.In this study,regional variations of microstructural features and mechanical properties in the femoral head of patients with proximal femur fracture were thoroughly investigated at the tissue level.The results of this study will help to elucidate the mechanism of femoral head fracture for reducing fracture risk and developing treatment strategies for the elderly.展开更多
Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament(ACL)reconstruction.Interference screw,as a surgical implant in ACL reconstruction,may influence natural loading transmis...Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament(ACL)reconstruction.Interference screw,as a surgical implant in ACL reconstruction,may influence natural loading transmission and contribute to tunnel enlargement.The aims of this study are(1)to quantify the alteration of strain energy density(SED)distribution after the anatomic single-bundle ACL reconstruction;and(2)to characterize the influence of screw length and diameter on the degree of the SED alteration.A validated finite element model of human knee joint was used.The screw length ranging from 20 to 30 mm with screw diameter ranging from 7 to 9 mm were investigated.In the post-operative knee,the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings,whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture.Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel;whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel.Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw.In consideration of both graft stability and SED alteration,a biodegradable interference screw with a long length is recommended,which could provide a beneficial mechanical environment at the distal part of the tunnel,and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel.These findings together with the clinical and histological factors could help to improve surgical outcome,and serve as a preliminary knowledge for the following study of biodegradable interference screw.展开更多
Objective Mechanical stretch regulates mesenchymal stem cell(MSC)function,which much more emphasis has been placed its prolonged effect on lineage differentiation,especially osteogenic differentiation.In contrast,ther...Objective Mechanical stretch regulates mesenchymal stem cell(MSC)function,which much more emphasis has been placed its prolonged effect on lineage differentiation,especially osteogenic differentiation.In contrast,there are few reports about its short term effect on MSC proliferation.In the present study,effects of short-term mechanical stretch on the proliferation and osteogenic differentiation of mesenchymal stem cell proliferation were investigated.In addition,the stretchinfluenced expression of transient receptor potential cation channel,subfamily C,member 1(TRPC1)was also investigated due to its mechanosensitivity and positive correlation with MSC proliferation.Methods MSCs,harvested from rat bone marrow,were seeded on collagen l-coated silicone chamber and exposed to mechanical stretch with various magnitude(0%,5%,10%and 15%)or various duration(2 h,6 h,12 h and 24 h).Cell proliferation was examined by cell counting kit-8(CCK-8)assay and cell cycle analysis.The gene and protein expression of two makers for osteogenic differentiation,collagen I and Cbfα1,and TRPC1 were determined by RT-PCR and western blotting,respectively.BMSC were harvested,and total RNA was isolated with Trizol reagent.A 2μg portion of total RNA was synthesized to cDNA according to the manufacturer s instructions.cDNA was used as a template for each PCR amplification.BMSC were solubilized in RIPA lysis buffer on ice for 30 min.Phenylmethane sulfonyl fluoride(PMSF)was added to avoid proteolysis.Equal portions of the cell lysates were separated on 10%sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)and transferred to polyvinylidene fluoride(PVDF)membranes.The membranes were incubated with primary antibodies to TRPC1 and GAPDH at4℃overnight to identify the specific proteins.The PVDF membranes were washed with TBST three times and incubated with a horseradish peroxidase(HRP)-conjugated secondary antibody.Immunoreactive bands were visualized using an enhanced chemiluminescent(ECL)system.Results The OD value for the three stretch cases(5%-15%)was increased^1.4-fold compared with that for control(0%).There is no significantly difference among the three stretch cases.The percentage of cells for three stretch cases were more in the S phase but less in the G0/G1 phase compared to those for control.The cell cycle distribution still had no significant difference among the three stretch cases.In addition,the stretch application for 24 h didn’t affect the gene or protein level for collagen I and Cbfα1 compared with those of control.Application of 10%stretch for 2 h didn’t affect TRPC1 gene or protein expression,but that application for 6-24 h significantly up-regulated TRPCl gene and protein level.That increase exhibited a stretch duration-independent manner.Conclusions Short-term mechanical stretch promoted MSC proliferation in a magnitude-independent manner,whereas had no effect on its oesteogenic differentiation.Paralleled to which,TRPC1 was up-regulated by stretch,implying that TRPCl may be implicated in that proliferation courses.Future work is still needed to confirm whether TRPC1 participates in that stretch-induced MSC proliferation using RPC1 blockade or knockout.展开更多
Background:Mg alloys have attractive properties,including biocompatibility,biodegradability,and ideal mechanical properties.Moreover,Mg alloys are regarded as one of the promising candidates for manufacturing ureteral...Background:Mg alloys have attractive properties,including biocompatibility,biodegradability,and ideal mechanical properties.Moreover,Mg alloys are regarded as one of the promising candidates for manufacturing ureteral stents.This study proposed a multi-objective optimization method based on the Kriging surrogate model,NSGA-III,and finite element analysis to improve the degradation performance of Mg alloy ureteral stents.Methods:The finite element model for the degradation of Mg alloy ureteral stents has been established to compare the degradation performance of the stents under different parameters.Latin hypercube sampling was adopted to generate train sample points in the design space.Meanwhile,the Kriging surrogate model was constructed between strut parameters and stent degradation behavior.The NSGA-III was utilized to determine the optimal solution in the global design space.Results:The optimized stent achieved 5.52degradation uniformity(M),10degradation time(DT),and 4work time(FT).The errors between the Kriging surrogate model and the finite element calculation results were less than 6%.Conclusion:The optimized stent achieved better degradation performance.The degradation behavior of stents was dependent on the design parameters.The multi-objective optimization method based on the Kriging surrogate model and finite element analysis was effective in stent design optimization problems.展开更多
Accurately characterizing the liver's mechanical properties is of paramount importance for disease diagnosis,treatment,surgical prosthetic modeling,and impact injury dummies.However,due to its inherent biological ...Accurately characterizing the liver's mechanical properties is of paramount importance for disease diagnosis,treatment,surgical prosthetic modeling,and impact injury dummies.However,due to its inherent biological soft tissue nature,the characterization of mechanical behavior varies across testing methods and sample types.In this study,we employed transmission electron microscope and Micro CT to observe the morphology of the marginal and center of rat livers and conducted macroscopic mechanical tests to characterize their elasticity and viscoelasticity.The results revealed that the central region displayed higher metabolic levels,elongated mitochondria,and an abundance of rough endoplasmic reticulum at the microscale.At the mesoscale,larger diameter portal veins were mainly distributed in the central region,while smaller diameter arteries were predominantly located at the periphery.At the macroscale,under a strain rate of 0.0167 s^(-1),no significant differences were observed in the elastic properties between the two regions.However,as the strain rate increased up to 0.167 s^(-1),the central region displayed higher porosity,resulting in reduced liquid loss,increased hardness,and higher viscosity compared to the periphery.Consequently,the liver demonstrated overall heterogeneity,with isotropic models suitable for the peripheral region,while more intricate models may be required to capture the complexity of the central region with its intricate vasculature.展开更多
Stem cell transplantation is an appealing potential therapy for vascular diseases and an indispensable key step in vascular tissue engineering.Substantial effort has been made to differentiate stem cells toward vascul...Stem cell transplantation is an appealing potential therapy for vascular diseases and an indispensable key step in vascular tissue engineering.Substantial effort has been made to differentiate stem cells toward vascular cell phenotypes,including endothelial cells(ECs)and smooth muscle cells.The microenvironment of vascular cells not only contains biochemical factors that influence differentiation but also exerts hemodynamic forces,such as shear stress and cyclic strain.More recently,studies have shown that shear stress can influence the differentiation of stem cells toward ECs.A deep understanding of the responses and underlying mechanisms involved in this process is essential for clinical translation.This review highlights current data supporting the role of shear stress in stem cell differentiation into ECs.Potential mechanisms and signaling cascades for transducing shear stress into a biological signal are proposed.Further study of stem cell responses to shear stress will be necessary to apply stem cells for pharmacological applications and cardiovascular implants in the realm of regenerative medicine.展开更多
Objective The apoptosis of vascular smooth muscle cells(VSMCs)influenced by abnormal cyclic stretch is crucial for vascular remodeling during hypertension.We explored that the causes of mechano-responsive lamin A/C ch...Objective The apoptosis of vascular smooth muscle cells(VSMCs)influenced by abnormal cyclic stretch is crucial for vascular remodeling during hypertension.We explored that the causes of mechano-responsive lamin A/C changingin aonormai cyclic stretcn and its roles in VSMC apoptosis.Methods and results Our previous vascular proteomics study revealed that LaminA/C is mechano-sensitive molecule.When VSMCs are subjected to cyclic stretch,the expression of LaminA/C is significantly changed which participates dysfunctions of VSMCs during hypertension.However,the molecular mechanism involved in regulation of LaminA/C expression and the role of LaminA/C in the VSMC apoptosis during cyclic stretch application are still unclear.In the present study,VSMCs were subjected to different amplitudes of cyclic steetch in vitro:5%cyclic stretch(physiological strain)or 15%cyclic stretch(pathological strain).The expression of 2 different selective cleavage isomers of LaminA/C,i.e.LaminA and LaminC,and the apoptosis of VSMCs were detected.The results showed that compared with 5%group,15%cyclic stretch significantly decreased the expression of LaminA and LaminC,and promoted the apoptosis of VSMCs.Using specific small interfering RNA(siRNA)transfection which targets on LMNA the encoding gene of LaminA/C,the expression of LaminA and LaminC in VSMCs was significantly decreased,and the apoptosis was significantly increased.In order to study the molecular mechanism involved in cyclic stretch regulating the expression of LaminA/C,we focused on the microRNA(miR).Bioinformatics analysis showed that the 3’untranslated region(3’UTR)of LMNA has two potential binding sites to miR-124-3p.Double luciferase reported system revealed that both sites have binding abilities to miR-124-3p.Under static condition,miR-124-3p inhibitor significantly up-regulated the expression levels of LaminA and LaminC,while the miR-124-3p mimics significantly down-regulated them.RT-PCR results showed that 15%cyclic stretch significantly up-regulated the expression of miR-124-3p compared with 5%cyclic stretch.Furthermore,in order to study the role of changeed LaminA/C in VSMC apoptosis,LMNA-specific siRNA was transfected to repress the expression of LaminA/C in VSMCs,and Protein/DNA microarray was used to detecte the activity of transcription factors.The transcription factors whose activity were changed significantly(increase or decrease more than 2 times)were analyzed by cluster analysis and ingenurity pathway analysis(IPA).Six transcription factors associated with apoptosis were screened,in which TP53 was activated by the specific siRNA transfection and the other 5 were inavtived,including TP53,CREB1,MYC,STAT1/5/6 and JUN.Using abdominal aorta coarctation hypertensive model,the change of miR-124-3p in VSMCs was explored in vivo.A marked increase of miR-124-3p in thoracic aorta was revealed compared with the sham-operated controls,and in situ FISH revealed that this increase was mainly in the VSMCs.Conclusions The present study suggest that abnormally increased cyclic stretch(15%)up-regulates the expression of miR-124-3p in VSMCs,which subsequently targets on the 3’UTR of LMNA and decreases the expression of nuclear envelope protein LaminA/C;the repressed LaminA/C may play an important role in the apoptosis of VSMCs by regulating the activity of virious transcription factors,such as TP53,CREB1,MYC,STAT1/5/6 and JUN.The present study may provide a new insight into understanding the molecular mechanisms of vascular remodeling.展开更多
Osteocytes act as mechanosensors in bone, which can send mechanical signals directly to osteoblasts through gap junctions. However, under physiological conditions the number of gap junctions is limited because of the ...Osteocytes act as mechanosensors in bone, which can send mechanical signals directly to osteoblasts through gap junctions. However, under physiological conditions the number of gap junctions is limited because of the quantity variance of the two kinds of cells. In this study, the possibility of indirect interaction between these two cells was investigated. A new flow champer was designed in which osteocytes and osteoblasts were cocultured in two champers separately. 0steocytes were exposed to fluid flow and then the ALP activity, osteocalcin and osteopotin of osteoblasts were determined. The results showed that either ALP activity or production of osteocalcin and osteopotin in osteoblasts that were cocuhured with sheared osteocytes increased, which indicated that osteocytes could regulate osteoblasts indirectly through some soluble factors.展开更多
This research investigates the formation of chitosan/poly (L-lactide) (CS/PLLA) porous composite scaffold using a novel emulsion freeze-drying technique. First, an oil in-water (O/W) emulsification system was us...This research investigates the formation of chitosan/poly (L-lactide) (CS/PLLA) porous composite scaffold using a novel emulsion freeze-drying technique. First, an oil in-water (O/W) emulsification system was used in the presence of surfactant Tween-80, in which CS solution was used as the water phase and PLLA solution was used as the oil phase. The emulsion was observed by inverted microscope (× 200). The emulsion droplet was spherical and uniform in size. FT-IR analysis revealed that there were hydrogen bonding interactions between CS and PLLA components. The microstructure and physical properties of the scaffolds were also analyzed. The SEM results showed that composite scaffolds formed well interconnected pore structure and homogenous distribution of CS and PLLA. When the content of PLLA reached 50%, the porosity of CS/PLLA composite scaffolds were between 83 %-91% and density in the range of 0.047 to 0.11 g/era3. The porosity showed a slight decrease and the density increased with the increase of PLLA dose. The compressive strength increased from 0.32 to 0.43 MPa, while the compressive modulus increased from 1.99 to 3.91 MPa as the PLLA contents increased from 10% to 50%.展开更多
Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson...Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.展开更多
Postoperative adhesion(POA)widely occurs in soft tissues and usually leads to chronic pain,dysfunction of adjacent organs and some acute complications,seriously reducing patients’quality of life and even being life-t...Postoperative adhesion(POA)widely occurs in soft tissues and usually leads to chronic pain,dysfunction of adjacent organs and some acute complications,seriously reducing patients’quality of life and even being life-threatening.Except for adhesiolysis,there are few effective methods to release existing adhesion.However,it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence.Hence,preventing POA formation has been regarded as the most effective clinical strategy.Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers.Nevertheless,even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent,thoroughly preventing POA formation is still challenging.Meanwhile,most biomaterials for POA prevention were designed based on limited experiences,not a solid theoretical basis,showing blindness.Hence,we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development.We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues,and named them as“membranous adhesion”,“vascular adhesion”,“adhesive adhesion”and“scarred adhesion”,respectively.Then,the process of the occurrence and development of POA were analyzed,and the main influencing factors in different stages were clarified.Further,we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors.Meanwhile,the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.展开更多
The performance of Aquatic Unmanned Aerial Vehicle(AquaUAV)has always been limited so far and far from practical applications,due to insufficient propulsion,large-resistance structure etc.Aerial-aquatic amphibians in ...The performance of Aquatic Unmanned Aerial Vehicle(AquaUAV)has always been limited so far and far from practical applications,due to insufficient propulsion,large-resistance structure etc.Aerial-aquatic amphibians in nature may facilitate the development of AquaUAV since their excellent amphibious locomotion capabilities evolved under long-term natural selection.This article will take four typical aerial-aquatic amphibians as representatives,i.e.,gannet,cormorant,flying fish and flying squid.We summarized the multi-mode locomotion process of common aerial-aquatic amphibians and the evolutionary trade-offs they have made to adapt to amphibious environments.The four typical propulsion mechanisms were investigated,which may further inspire the propulsion design of the AquaUAV.And their morphological models could guide the layout optimization.Finally,we reviewed the state of art in AquaUAV to validate the potential value of our bioinspiration,and discussed the futureprospects.展开更多
Irisin,a myokine mainly secreted from contracted skeleton muscle,plays a profound role in bone formation and remodeling.Although irisin has been revealed to elevate bone mass in vivo,details whether there is a dosedep...Irisin,a myokine mainly secreted from contracted skeleton muscle,plays a profound role in bone formation and remodeling.Although irisin has been revealed to elevate bone mass in vivo,details whether there is a dosedependent relationship between irisin and bone formation remain unclear.In this study,we explored the dosedependent effects of irisin on osteoblast proliferation and differentiation.Our results first demonstrated a remarkable increase in cell proliferation rate and viability in response to elevated concentrations of r-irisin,which was further enhanced over time.Notably,this increase was subject to complex dose-response relationships as the proliferation-enhancing effects of r-irisin may have a saturation point between 10 ng/ml and 100 ng/ml.Furthermore,we determined that 1,10,and 100 ng/ml r-irisin were able to upregulate the expression of osteogenic transcription factors(Runx2,Osx,and Atf4),as well as osteogenic markers(Alp,Col1a1 and Spp1),albeit without significant difference among these 3 concentrations.Interestingly,nutrient-depleted osteoblasts and those with standard culture showed distinct responses to higher doses of irisin regarding osteogenic differentiation.Further investigation is required to uncover the molecular mechanisms underlying the observed tandem effects of irisin on osteogenesis.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
More than half of stroke patients live with different levels of motor dysfunction after receiving routine rehabilitation treatments.Therefore,new rehabilitation technologies are urgently needed as auxiliary treatments...More than half of stroke patients live with different levels of motor dysfunction after receiving routine rehabilitation treatments.Therefore,new rehabilitation technologies are urgently needed as auxiliary treatments for motor rehabilitation.Based on routine rehabilitation treatments,a new intelligent rehabilitation platform has been developed for accurate evaluation of function and rehabilitation training.The emerging intelligent rehabilitation techniques can promote the development of motor function rehabilitation in terms of informatization,standardization,and intelligence.Traditional assessment methods are mostly subjective,depending on the experience and expertise of clinicians,and lack standardization and precision.It is therefore difficult to track functional changes during the rehabilitation process.Emerging intelligent rehabilitation techniques provide objective and accurate functional assessment for stroke patients that can promote improvement of clinical guidance for treatment.Artificial intelligence and neural networks play a critical role in intelligent rehabilitation.Multiple novel techniques,such as braincomputer interfaces,virtual reality,neural circuit-magnetic stimulation,and robot-assisted therapy,have been widely used in the clinic.This review summarizes the emerging intelligent rehabilitation techniques for the evaluation and treatment of motor dysfunction caused by nervous system diseases.展开更多
It has been well recognized that the development and use of artificial materials with high osteogenic ability is one of the most promising means to replace bone grafting that has exhibited various negative effects.The...It has been well recognized that the development and use of artificial materials with high osteogenic ability is one of the most promising means to replace bone grafting that has exhibited various negative effects.The biomimetic features and unique physiochemical properties of nanomaterials play important roles in stimulating cellular functions and guiding tissue regeneration.But efficacy degree of some nanomaterials to promote specific tissue formation is still not clear.We hereby comparatively studied the osteogenic ability of our treated multiwalled carbon nanotubes(MCNTs)and the main inorganic mineral component of natural bone,nano-hydroxyapatite(nHA)in the same system,and tried to tell the related mechanism.In vitro culture of human adiposederived mesenchymal stem cells(HASCs)on the MCNTs and nHA demonstrated that although there was no significant difference in the cell adhesion amount between on the MCNTs and nHA,the cell attachment strength and proliferation on the MCNTs were better.Most importantly,the MCNTs could induce osteogenic differentiation of the HASCs better than the nHA,the possible mechanism of which was found to be that the MCNTs could activate Notch involved signaling pathways by concentrating more proteins,including specific bone-inducing ones.Moreover,the MCNTs could induce ectopic bone formation in vivo while the nHA could not,which might be because MCNTs could stimulate inducible cells in tissues to form inductive bone better than nHA by concentrating more proteins including specific bone-inducing ones secreted from M2 macrophages.Therefore,MCNTs might be more effective materials for accelerating bone formation even than nHA.展开更多
基金Supported by the National Natural Science Foundation of China,No.82271843 and 31700779the Key Project supported by Medical Science and Technology Development Foundation,Nanjing Department of Health,No.ZKX20019the Natural Science Foundation of Jiangsu Province,No.BK20200137.
文摘Mesenchymal stem cells(MSCs)are stem/progenitor cells capable of self-renewal and differentiation into osteoblasts,chondrocytes and adipocytes.The transformation of multipotent MSCs to adipocytes mainly involves two subsequent steps from MSCs to preadipocytes and further preadipocytes into adipocytes,in which the process MSCs are precisely controlled to commit to the adipogenic lineage and then mature into adipocytes.Previous studies have shown that the master transcription factors C/enhancer-binding protein alpha and peroxisome proliferation activator receptor gamma play vital roles in adipogenesis.However,the mechanism underlying the adipogenic differentiation of MSCs is not fully understood.Here,the current knowledge of adipogenic differentiation in MSCs is reviewed,focusing on signaling pathways,noncoding RNAs and epigenetic effects on DNA methylation and acetylation during MSC differentiation.Finally,the relationship between maladipogenic differentiation and diseases is briefly discussed.We hope that this review can broaden and deepen our understanding of how MSCs turn into adipocytes.
基金financial support from the National Natural Science Foundation of China(Nos.11872097,82074463,11827803,and U20A20390)the National Key R&D Program of China(No.2020YFC0122204)+1 种基金the 111 Project(No.B13003)the International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of China。
文摘Current electro spun membranes used for pulp capping still lack the sustained-release capability and long-term anti-inflammatory effects that are favorable for dental pulp regeneration.In this work,a single-layered poly(lac tic acid)(PLA)electro spun membrane loaded with amorphous calcium phosphate(ACP)and aspirin(PLA/ACP/Aspirin membrane,i.e.,PA A membrane)is sandwiched between two poly(lactic-co-glycolic acid)(PLGA)electro spun membranes as a novel sandwich-structured PLGA and PA A composite electro spun membrane(PLGA-PAA membrane)to resolve the need for sustained-release design and anti-inflammatory effects.Contact angle measurements indicate that the PLGA-PAA membrane is more hydrophilic than the PAA membrane.An in vitro release study reveals that PLGA membranes coated on PAA membrane could slightly slow down ion release,while signiificantly prolonging aspirin release.We also co-cultured membranes with dental pulp stem cells(DPSCs)and human monocytic THP-1 cells to evaluate their osteogenic ability and anti-inflammatory effects,respectively.Compared with the PAA membrane,the PLGA-PAA membrane promotes cell adhesion,proliferation,and osteogenic differentiation.A prolonged anti-inflammatory effect of up to 18 days is also observed in the PLGA-PAA group.The results suggest a promising strategy for fabricating an electro spun membrane system with controlled release capabilities and long-term anti-inflammatory effects for use as pulp-capping material for regeneration of the dentin-pulp complex.
基金supported in part by the National Natural Science Foundation of China(U2241228,62273019,61825305,U1933125,72192820,72192824,62171274)the China Postdoctoral Science Foundation(2022M710093)the Open Project Program of the Key Laboratory for Agricultural Machinery Intelligent Control and Manufacturing of Fujian Education Institutions(AMICM202102)。
文摘This work presents a trajectory tracking control method for snake robots.This method eliminates the influence of time-varying interferences on the body and reduces the offset error of a robot with a predetermined trajectory.The optimized line-of-sight(LOS)guidance strategy drives the robot’s steering angle to maintain its anti-sideslip ability by predicting position errors and interferences.Then,the predictions of system parameters and viscous friction coefficients can compensate for the joint torque control input.The compensation is adopted to enhance the compatibility of a robot within ever-changing environments.Simulation and experimental outcomes show that our work can decrease the fluctuation peak of the tracking errors,reduce adjustment time,and improve accuracy.
基金supported by the US DOD(W81XWH-12-2-0008)the National Institutes of Health(DE022327,HL136231,TR001711)the National Natural Science Foundation of China(Grant No.31470915)
文摘Bone tissue engineering is an exciting approach to directly repair bone defects or engineer bone tissue for transplantation.Biomaterials play a pivotal role in providing a template and extracellular environment to support regenerative cells and promote tissue regeneration. A variety of signaling cues have been identified to regulate cellular activity, tissue development, and the healing process. Numerous studies and trials have shown the promise of tissue engineering, but successful translations of bone tissue engineering research into clinical applications have been limited, due in part to a lack of optimal delivery systems for these signals. Biomedical engineers are therefore highly motivated to develop biomimetic drug delivery systems, which benefit from mimicking signaling molecule release or presentation by the native extracellular matrix during development or the natural healing process. Engineered biomimetic drug delivery systems aim to provide control over the location, timing, and release kinetics of the signal molecules according to the drug's physiochemical properties and specific biological mechanisms. This article reviews biomimetic strategies in signaling delivery for bone tissue engineering, with a focus on delivery systems rather than specific molecules. Both fundamental considerations and specific design strategies are discussed with examples of recent research progress, demonstrating the significance and potential of biomimetic delivery systems for bone tissue engineering.
基金supported by the National Natural Science Foundation of China(Nos.11322223,11432016,81471753 and 11272134)the 973 Program(No.2012CB821202)
文摘This study aims to investigate the regional variations of trabecular morphological parameters and mechanical parameters of the femoral head,as well as to determine the relationship between trabecular morphological and mechanical parameters.Seven femoral heads from patients with fractured proximal femur were scanned using a micro-CT system.Each femoral head was divided into 12 sub-regions according to the trabecular orientation.One 125 mm^3 trabecular cubic model was reconstructed from each sub-region.A total of 81 trabecular models were reconstructed,except three destroyed sub-regions from two femoral heads during the surgery.Trabecular morphological parameters,i.e.trabecular separation(Tb.Sp),trabecular thickness(Tb.Th),specific bone surface(BS/B V),bone volume fraction(BV/TV),structural model index(SMI),and degree of anisotropy(DA) were measured.Micro-finite element analyses were performed for each cube to obtain the apparent Young's modulus and tissue level von Mises stress distribution under 1%compressive strain along three orthogonal directions,respectively.Results revealed significant regional variations in the morphological parameters(P〈0.05).Young's moduli along the trabecular orientation were significantly higher than those along the other two directions.In general,trabecular mechanical properties in the medial region were lower than those in the lateral region.Trabecular mechanical parameters along the trabecular orientation were significantly correlated with BS/BV,BV/TV,Tb.Th,and DA.In this study,regional variations of microstructural features and mechanical properties in the femoral head of patients with proximal femur fracture were thoroughly investigated at the tissue level.The results of this study will help to elucidate the mechanism of femoral head fracture for reducing fracture risk and developing treatment strategies for the elderly.
基金supported by the National Science & Technology Pillar Program of China(2012BAI18B07 and 2012BAI22B02)the National Natural Science Foundation of China(10925208 and 11120101001)the National Key Lab of Virtual Reality Technology
文摘Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament(ACL)reconstruction.Interference screw,as a surgical implant in ACL reconstruction,may influence natural loading transmission and contribute to tunnel enlargement.The aims of this study are(1)to quantify the alteration of strain energy density(SED)distribution after the anatomic single-bundle ACL reconstruction;and(2)to characterize the influence of screw length and diameter on the degree of the SED alteration.A validated finite element model of human knee joint was used.The screw length ranging from 20 to 30 mm with screw diameter ranging from 7 to 9 mm were investigated.In the post-operative knee,the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings,whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture.Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel;whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel.Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw.In consideration of both graft stability and SED alteration,a biodegradable interference screw with a long length is recommended,which could provide a beneficial mechanical environment at the distal part of the tunnel,and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel.These findings together with the clinical and histological factors could help to improve surgical outcome,and serve as a preliminary knowledge for the following study of biodegradable interference screw.
基金supported by the National Natural Science Foundation of China ( 11872010)
文摘Objective Mechanical stretch regulates mesenchymal stem cell(MSC)function,which much more emphasis has been placed its prolonged effect on lineage differentiation,especially osteogenic differentiation.In contrast,there are few reports about its short term effect on MSC proliferation.In the present study,effects of short-term mechanical stretch on the proliferation and osteogenic differentiation of mesenchymal stem cell proliferation were investigated.In addition,the stretchinfluenced expression of transient receptor potential cation channel,subfamily C,member 1(TRPC1)was also investigated due to its mechanosensitivity and positive correlation with MSC proliferation.Methods MSCs,harvested from rat bone marrow,were seeded on collagen l-coated silicone chamber and exposed to mechanical stretch with various magnitude(0%,5%,10%and 15%)or various duration(2 h,6 h,12 h and 24 h).Cell proliferation was examined by cell counting kit-8(CCK-8)assay and cell cycle analysis.The gene and protein expression of two makers for osteogenic differentiation,collagen I and Cbfα1,and TRPC1 were determined by RT-PCR and western blotting,respectively.BMSC were harvested,and total RNA was isolated with Trizol reagent.A 2μg portion of total RNA was synthesized to cDNA according to the manufacturer s instructions.cDNA was used as a template for each PCR amplification.BMSC were solubilized in RIPA lysis buffer on ice for 30 min.Phenylmethane sulfonyl fluoride(PMSF)was added to avoid proteolysis.Equal portions of the cell lysates were separated on 10%sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)and transferred to polyvinylidene fluoride(PVDF)membranes.The membranes were incubated with primary antibodies to TRPC1 and GAPDH at4℃overnight to identify the specific proteins.The PVDF membranes were washed with TBST three times and incubated with a horseradish peroxidase(HRP)-conjugated secondary antibody.Immunoreactive bands were visualized using an enhanced chemiluminescent(ECL)system.Results The OD value for the three stretch cases(5%-15%)was increased^1.4-fold compared with that for control(0%).There is no significantly difference among the three stretch cases.The percentage of cells for three stretch cases were more in the S phase but less in the G0/G1 phase compared to those for control.The cell cycle distribution still had no significant difference among the three stretch cases.In addition,the stretch application for 24 h didn’t affect the gene or protein level for collagen I and Cbfα1 compared with those of control.Application of 10%stretch for 2 h didn’t affect TRPC1 gene or protein expression,but that application for 6-24 h significantly up-regulated TRPCl gene and protein level.That increase exhibited a stretch duration-independent manner.Conclusions Short-term mechanical stretch promoted MSC proliferation in a magnitude-independent manner,whereas had no effect on its oesteogenic differentiation.Paralleled to which,TRPC1 was up-regulated by stretch,implying that TRPCl may be implicated in that proliferation courses.Future work is still needed to confirm whether TRPC1 participates in that stretch-induced MSC proliferation using RPC1 blockade or knockout.
基金supported by the National Natural Science Foundation of China(12172034,U20A20390,and 11827803)Beijing Municipal Natural Science Foundation(7212205)+1 种基金the 111 project(B13003)the Fundamental Research Funds for the Central Universities.
文摘Background:Mg alloys have attractive properties,including biocompatibility,biodegradability,and ideal mechanical properties.Moreover,Mg alloys are regarded as one of the promising candidates for manufacturing ureteral stents.This study proposed a multi-objective optimization method based on the Kriging surrogate model,NSGA-III,and finite element analysis to improve the degradation performance of Mg alloy ureteral stents.Methods:The finite element model for the degradation of Mg alloy ureteral stents has been established to compare the degradation performance of the stents under different parameters.Latin hypercube sampling was adopted to generate train sample points in the design space.Meanwhile,the Kriging surrogate model was constructed between strut parameters and stent degradation behavior.The NSGA-III was utilized to determine the optimal solution in the global design space.Results:The optimized stent achieved 5.52degradation uniformity(M),10degradation time(DT),and 4work time(FT).The errors between the Kriging surrogate model and the finite element calculation results were less than 6%.Conclusion:The optimized stent achieved better degradation performance.The degradation behavior of stents was dependent on the design parameters.The multi-objective optimization method based on the Kriging surrogate model and finite element analysis was effective in stent design optimization problems.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2241273,12172034,U20A20390,and 11827803)the Beijing Municipal Natural Science Foundation(Grant No.7212205)+1 种基金the 111 project(Grant No.B13003)the Fundamental Research Funds for the Central Universities.
文摘Accurately characterizing the liver's mechanical properties is of paramount importance for disease diagnosis,treatment,surgical prosthetic modeling,and impact injury dummies.However,due to its inherent biological soft tissue nature,the characterization of mechanical behavior varies across testing methods and sample types.In this study,we employed transmission electron microscope and Micro CT to observe the morphology of the marginal and center of rat livers and conducted macroscopic mechanical tests to characterize their elasticity and viscoelasticity.The results revealed that the central region displayed higher metabolic levels,elongated mitochondria,and an abundance of rough endoplasmic reticulum at the microscale.At the mesoscale,larger diameter portal veins were mainly distributed in the central region,while smaller diameter arteries were predominantly located at the periphery.At the macroscale,under a strain rate of 0.0167 s^(-1),no significant differences were observed in the elastic properties between the two regions.However,as the strain rate increased up to 0.167 s^(-1),the central region displayed higher porosity,resulting in reduced liquid loss,increased hardness,and higher viscosity compared to the periphery.Consequently,the liver demonstrated overall heterogeneity,with isotropic models suitable for the peripheral region,while more intricate models may be required to capture the complexity of the central region with its intricate vasculature.
基金Supported by National Key R&D Program of China,No.2017YFC1104703National Natural Science Foundation of China,No.31771042 and No.11302020.
文摘Stem cell transplantation is an appealing potential therapy for vascular diseases and an indispensable key step in vascular tissue engineering.Substantial effort has been made to differentiate stem cells toward vascular cell phenotypes,including endothelial cells(ECs)and smooth muscle cells.The microenvironment of vascular cells not only contains biochemical factors that influence differentiation but also exerts hemodynamic forces,such as shear stress and cyclic strain.More recently,studies have shown that shear stress can influence the differentiation of stem cells toward ECs.A deep understanding of the responses and underlying mechanisms involved in this process is essential for clinical translation.This review highlights current data supporting the role of shear stress in stem cell differentiation into ECs.Potential mechanisms and signaling cascades for transducing shear stress into a biological signal are proposed.Further study of stem cell responses to shear stress will be necessary to apply stem cells for pharmacological applications and cardiovascular implants in the realm of regenerative medicine.
基金supported by grants from the National Natural Science Foundation of China( 11572199 and 11625209)
文摘Objective The apoptosis of vascular smooth muscle cells(VSMCs)influenced by abnormal cyclic stretch is crucial for vascular remodeling during hypertension.We explored that the causes of mechano-responsive lamin A/C changingin aonormai cyclic stretcn and its roles in VSMC apoptosis.Methods and results Our previous vascular proteomics study revealed that LaminA/C is mechano-sensitive molecule.When VSMCs are subjected to cyclic stretch,the expression of LaminA/C is significantly changed which participates dysfunctions of VSMCs during hypertension.However,the molecular mechanism involved in regulation of LaminA/C expression and the role of LaminA/C in the VSMC apoptosis during cyclic stretch application are still unclear.In the present study,VSMCs were subjected to different amplitudes of cyclic steetch in vitro:5%cyclic stretch(physiological strain)or 15%cyclic stretch(pathological strain).The expression of 2 different selective cleavage isomers of LaminA/C,i.e.LaminA and LaminC,and the apoptosis of VSMCs were detected.The results showed that compared with 5%group,15%cyclic stretch significantly decreased the expression of LaminA and LaminC,and promoted the apoptosis of VSMCs.Using specific small interfering RNA(siRNA)transfection which targets on LMNA the encoding gene of LaminA/C,the expression of LaminA and LaminC in VSMCs was significantly decreased,and the apoptosis was significantly increased.In order to study the molecular mechanism involved in cyclic stretch regulating the expression of LaminA/C,we focused on the microRNA(miR).Bioinformatics analysis showed that the 3’untranslated region(3’UTR)of LMNA has two potential binding sites to miR-124-3p.Double luciferase reported system revealed that both sites have binding abilities to miR-124-3p.Under static condition,miR-124-3p inhibitor significantly up-regulated the expression levels of LaminA and LaminC,while the miR-124-3p mimics significantly down-regulated them.RT-PCR results showed that 15%cyclic stretch significantly up-regulated the expression of miR-124-3p compared with 5%cyclic stretch.Furthermore,in order to study the role of changeed LaminA/C in VSMC apoptosis,LMNA-specific siRNA was transfected to repress the expression of LaminA/C in VSMCs,and Protein/DNA microarray was used to detecte the activity of transcription factors.The transcription factors whose activity were changed significantly(increase or decrease more than 2 times)were analyzed by cluster analysis and ingenurity pathway analysis(IPA).Six transcription factors associated with apoptosis were screened,in which TP53 was activated by the specific siRNA transfection and the other 5 were inavtived,including TP53,CREB1,MYC,STAT1/5/6 and JUN.Using abdominal aorta coarctation hypertensive model,the change of miR-124-3p in VSMCs was explored in vivo.A marked increase of miR-124-3p in thoracic aorta was revealed compared with the sham-operated controls,and in situ FISH revealed that this increase was mainly in the VSMCs.Conclusions The present study suggest that abnormally increased cyclic stretch(15%)up-regulates the expression of miR-124-3p in VSMCs,which subsequently targets on the 3’UTR of LMNA and decreases the expression of nuclear envelope protein LaminA/C;the repressed LaminA/C may play an important role in the apoptosis of VSMCs by regulating the activity of virious transcription factors,such as TP53,CREB1,MYC,STAT1/5/6 and JUN.The present study may provide a new insight into understanding the molecular mechanisms of vascular remodeling.
基金National Natural Science Foundation of China grant number: 10872024
文摘Osteocytes act as mechanosensors in bone, which can send mechanical signals directly to osteoblasts through gap junctions. However, under physiological conditions the number of gap junctions is limited because of the quantity variance of the two kinds of cells. In this study, the possibility of indirect interaction between these two cells was investigated. A new flow champer was designed in which osteocytes and osteoblasts were cocultured in two champers separately. 0steocytes were exposed to fluid flow and then the ALP activity, osteocalcin and osteopotin of osteoblasts were determined. The results showed that either ALP activity or production of osteocalcin and osteopotin in osteoblasts that were cocuhured with sheared osteocytes increased, which indicated that osteocytes could regulate osteoblasts indirectly through some soluble factors.
基金National Nature Science Foundation of China grant number: 50803032, 10925208, 11032012, 11002016 and 30800217Fundamental Research Funds for the Central Universities
文摘This research investigates the formation of chitosan/poly (L-lactide) (CS/PLLA) porous composite scaffold using a novel emulsion freeze-drying technique. First, an oil in-water (O/W) emulsification system was used in the presence of surfactant Tween-80, in which CS solution was used as the water phase and PLLA solution was used as the oil phase. The emulsion was observed by inverted microscope (× 200). The emulsion droplet was spherical and uniform in size. FT-IR analysis revealed that there were hydrogen bonding interactions between CS and PLLA components. The microstructure and physical properties of the scaffolds were also analyzed. The SEM results showed that composite scaffolds formed well interconnected pore structure and homogenous distribution of CS and PLLA. When the content of PLLA reached 50%, the porosity of CS/PLLA composite scaffolds were between 83 %-91% and density in the range of 0.047 to 0.11 g/era3. The porosity showed a slight decrease and the density increased with the increase of PLLA dose. The compressive strength increased from 0.32 to 0.43 MPa, while the compressive modulus increased from 1.99 to 3.91 MPa as the PLLA contents increased from 10% to 50%.
文摘Non-invasive cerebral neuromodulation technologies are essential for the reorganization of cerebral neural networks,which have been widely applied in the field of central neurological diseases,such as stroke,Parkinson’s disease,and mental disorders.Although significant advances have been made in neuromodulation technologies,the identification of optimal neurostimulation paramete rs including the co rtical target,duration,and inhibition or excitation pattern is still limited due to the lack of guidance for neural circuits.Moreove r,the neural mechanism unde rlying neuromodulation for improved behavioral performance remains poorly understood.Recently,advancements in neuroimaging have provided insight into neuromodulation techniques.Functional near-infrared spectroscopy,as a novel non-invasive optical brain imaging method,can detect brain activity by measuring cerebral hemodynamics with the advantages of portability,high motion tole rance,and anti-electromagnetic interference.Coupling functional near-infra red spectroscopy with neuromodulation technologies offe rs an opportunity to monitor the cortical response,provide realtime feedbac k,and establish a closed-loop strategy integrating evaluation,feedbac k,and intervention for neurostimulation,which provides a theoretical basis for development of individualized precise neuro rehabilitation.We aimed to summarize the advantages of functional near-infra red spectroscopy and provide an ove rview of the current research on functional near-infrared spectroscopy in transcranial magnetic stimulation,transcranial electrical stimulation,neurofeedback,and braincomputer interfaces.Furthermore,the future perspectives and directions for the application of functional near-infrared spectroscopy in neuromodulation are summarized.In conclusion,functional near-infrared spectroscopy combined with neuromodulation may promote the optimization of central pellral reorganization to achieve better functional recovery form central nervous system diseases.
基金financial support from the National Natural Science Foundation of China(Nos.32171345,T2288101,U20A20390,and 11827803)Fok Ying Tung Education Foundation(No.141039)+1 种基金International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of China,the 111 Project(No.B13003)the Academic Excellence Foundation of BUAA for PhD Students.
文摘Postoperative adhesion(POA)widely occurs in soft tissues and usually leads to chronic pain,dysfunction of adjacent organs and some acute complications,seriously reducing patients’quality of life and even being life-threatening.Except for adhesiolysis,there are few effective methods to release existing adhesion.However,it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence.Hence,preventing POA formation has been regarded as the most effective clinical strategy.Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers.Nevertheless,even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent,thoroughly preventing POA formation is still challenging.Meanwhile,most biomaterials for POA prevention were designed based on limited experiences,not a solid theoretical basis,showing blindness.Hence,we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development.We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues,and named them as“membranous adhesion”,“vascular adhesion”,“adhesive adhesion”and“scarred adhesion”,respectively.Then,the process of the occurrence and development of POA were analyzed,and the main influencing factors in different stages were clarified.Further,we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors.Meanwhile,the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.
基金supported by the National Science Foundation of China(62103035)Beijing Natural Science Foundation(3222016)+1 种基金the China Postdoctoral Science Foundation(2021M690337)the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)。
文摘The performance of Aquatic Unmanned Aerial Vehicle(AquaUAV)has always been limited so far and far from practical applications,due to insufficient propulsion,large-resistance structure etc.Aerial-aquatic amphibians in nature may facilitate the development of AquaUAV since their excellent amphibious locomotion capabilities evolved under long-term natural selection.This article will take four typical aerial-aquatic amphibians as representatives,i.e.,gannet,cormorant,flying fish and flying squid.We summarized the multi-mode locomotion process of common aerial-aquatic amphibians and the evolutionary trade-offs they have made to adapt to amphibious environments.The four typical propulsion mechanisms were investigated,which may further inspire the propulsion design of the AquaUAV.And their morphological models could guide the layout optimization.Finally,we reviewed the state of art in AquaUAV to validate the potential value of our bioinspiration,and discussed the futureprospects.
基金The study was supported by National Natural Science Foundation of China(No.12172034,U2241273,11827803,U20A20390)Beijing Municipal Natural Science Foundation(7212205)+1 种基金the 111 project(B13003)the Fundamental Research Funds for the Central Universities.
文摘Irisin,a myokine mainly secreted from contracted skeleton muscle,plays a profound role in bone formation and remodeling.Although irisin has been revealed to elevate bone mass in vivo,details whether there is a dosedependent relationship between irisin and bone formation remain unclear.In this study,we explored the dosedependent effects of irisin on osteoblast proliferation and differentiation.Our results first demonstrated a remarkable increase in cell proliferation rate and viability in response to elevated concentrations of r-irisin,which was further enhanced over time.Notably,this increase was subject to complex dose-response relationships as the proliferation-enhancing effects of r-irisin may have a saturation point between 10 ng/ml and 100 ng/ml.Furthermore,we determined that 1,10,and 100 ng/ml r-irisin were able to upregulate the expression of osteogenic transcription factors(Runx2,Osx,and Atf4),as well as osteogenic markers(Alp,Col1a1 and Spp1),albeit without significant difference among these 3 concentrations.Interestingly,nutrient-depleted osteoblasts and those with standard culture showed distinct responses to higher doses of irisin regarding osteogenic differentiation.Further investigation is required to uncover the molecular mechanisms underlying the observed tandem effects of irisin on osteogenesis.
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the National Key Research and Development Project of China,No.2020YFC2004200(to ZYL)the National Natural Science Foundation of China,Nos.61761166007(to ZYL),81772453(to DSX),81974358(to DSX),31771071(to ZYL)Fundamental Research Funds for Central Public Welfare Research Institutes,No.118009001000160001(to ZYL)。
文摘More than half of stroke patients live with different levels of motor dysfunction after receiving routine rehabilitation treatments.Therefore,new rehabilitation technologies are urgently needed as auxiliary treatments for motor rehabilitation.Based on routine rehabilitation treatments,a new intelligent rehabilitation platform has been developed for accurate evaluation of function and rehabilitation training.The emerging intelligent rehabilitation techniques can promote the development of motor function rehabilitation in terms of informatization,standardization,and intelligence.Traditional assessment methods are mostly subjective,depending on the experience and expertise of clinicians,and lack standardization and precision.It is therefore difficult to track functional changes during the rehabilitation process.Emerging intelligent rehabilitation techniques provide objective and accurate functional assessment for stroke patients that can promote improvement of clinical guidance for treatment.Artificial intelligence and neural networks play a critical role in intelligent rehabilitation.Multiple novel techniques,such as braincomputer interfaces,virtual reality,neural circuit-magnetic stimulation,and robot-assisted therapy,have been widely used in the clinic.This review summarizes the emerging intelligent rehabilitation techniques for the evaluation and treatment of motor dysfunction caused by nervous system diseases.
基金The authors acknowledge the financial supports from the National Natural Science Foundation of China(No.31771042)Fok Ying Tung Education Foundation(No.141039)+1 种基金State Key Laboratory of New Ceramic and Fine Processing Tsinghua University,Fund of Key Laboratory of Advanced Materials of Ministry of Education(No.2020AML10)International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of China,and the 111 Project(No.B13003).
文摘It has been well recognized that the development and use of artificial materials with high osteogenic ability is one of the most promising means to replace bone grafting that has exhibited various negative effects.The biomimetic features and unique physiochemical properties of nanomaterials play important roles in stimulating cellular functions and guiding tissue regeneration.But efficacy degree of some nanomaterials to promote specific tissue formation is still not clear.We hereby comparatively studied the osteogenic ability of our treated multiwalled carbon nanotubes(MCNTs)and the main inorganic mineral component of natural bone,nano-hydroxyapatite(nHA)in the same system,and tried to tell the related mechanism.In vitro culture of human adiposederived mesenchymal stem cells(HASCs)on the MCNTs and nHA demonstrated that although there was no significant difference in the cell adhesion amount between on the MCNTs and nHA,the cell attachment strength and proliferation on the MCNTs were better.Most importantly,the MCNTs could induce osteogenic differentiation of the HASCs better than the nHA,the possible mechanism of which was found to be that the MCNTs could activate Notch involved signaling pathways by concentrating more proteins,including specific bone-inducing ones.Moreover,the MCNTs could induce ectopic bone formation in vivo while the nHA could not,which might be because MCNTs could stimulate inducible cells in tissues to form inductive bone better than nHA by concentrating more proteins including specific bone-inducing ones secreted from M2 macrophages.Therefore,MCNTs might be more effective materials for accelerating bone formation even than nHA.