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
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
Due to the close physical interaction between human and machine in process of gait training, lower limb exoskeletons should be safe, comfortable and able to smoothly transfer desired driving force/moments to the patie...Due to the close physical interaction between human and machine in process of gait training, lower limb exoskeletons should be safe, comfortable and able to smoothly transfer desired driving force/moments to the patients. Correlatively, in kinematics the exoskeletons are required to be compatible with human lower limbs and thereby to avoid the uncontrollable interactional loads at the human-machine interfaces. Such requirement makes the structure design of exoskeletons very difficult because the human-machine closed chains are complicated. In addition, both the axis misalignments and the kinematic character difference between the exoskeleton and human joints should be taken into account. By analyzing the DOF（degree of freedom） of the whole human-machine closed chain, the human-machine kinematic incompatibility of lower limb exoskeletons is studied. An effective method for the structure design of lower limb exoskeletons, which are kinematically compatible with human lower limb, is proposed. Applying this method, the structure synthesis of the lower limb exoskeletons containing only one-DOF revolute and prismatic joints is investigated; the feasible basic structures of exoskeletons are developed and classified into three different categories. With the consideration of quasi-anthropopathic feature, structural simplicity and wearable comfort of lower limb exoskeletons, a joint replacement and structure comparison based approach to select the ideal structures of lower limb exoskeletons is proposed, by which three optimal exoskeleton structures are obtained. This paper indicates that the human-machine closed chain formed by the exoskeleton and human lower limb should be an even-constrained kinematic system in order to avoid the uncontrollable human-machine interactional loads. The presented method for the structure design of lower limb exoskeletons is universal and simple, and hence can be applied to other kinds of wearable exoskeletons.展开更多
The existing research of steering comfort mainly focuses on the subjective evaluation,aiming at designing and optimizing the steering system.In the development of steering system,especially the evaluation of steering ...The existing research of steering comfort mainly focuses on the subjective evaluation,aiming at designing and optimizing the steering system.In the development of steering system,especially the evaluation of steering comfort,the objective evaluation methods considered the kinematic characteristics of driver steering maneuver are not proposed,which means that the objective evaluation of steering cannot be conducted with the evaluation of kinematic characteristics of driver in steering maneuver.In order to propose the objective evaluation methods of steering comfort,the evaluation of steering movement quality of driver is developed on the basis of the study of the kinematic characteristics of steering maneuver.First,the steering motion trajectories of the driver in both comfortable and certain extreme uncomfortable operation conditions are detected using the Vicon motion capture system.The operation conditions are under the restrictions of the vertical height and horizontal distance between steering wheel center and the H-point of driver,and the steering resisting torque else.Next,the movement quality evaluation of driver steering maneuver is assessed using twelve kinds of evaluation indices based on the kinematic analyses of the steering motion trajectories to propose an objective evaluation method.Finally,an integrated discomfort index of steering maneuver is proposed on the basis of the regression analysis of subjective evaluation rating and the movement quality evaluation indices,including the Jerk,Discomfort and Joint Torque indices.The test results show that the proposed integrated discomfort index gives a good fitting with the subjective evaluation of discomfort,which means it can be used to evaluate or predict the discomfort level of steering maneuver.This paper proposes an objective evaluation method of steering comfort based on the movement quality evaluation of driver steering maneuver.展开更多
OSAHS(Obstructive Sleep Apnea Hypopnea Syndrome)is a respiratory disease mainly characterized by limited and repeated pauses of breathing in sleep.Currently,the optimal treatment is to apply CPAP(Continuous Positive A...OSAHS(Obstructive Sleep Apnea Hypopnea Syndrome)is a respiratory disease mainly characterized by limited and repeated pauses of breathing in sleep.Currently,the optimal treatment is to apply CPAP(Continuous Positive Airway Pressure)ventilation on the upper airway of the patient through a household respiratory machine.However,if the ventilator mask is designed improperly,it might cause the residue and repeated inhalation of CO2,which will exert an adverse impact on the therapeutic effect.Present research numerically analyzed the CO2 transportation inside a commercial ventilator mask(Mirage SoftGel,ResMed,Australia)based on the reconstructed 3D numerical model of a volunteer's face and performed the improved design of the ventilator mask in terms of the CO2 residual concentration below the nostrils.The fluid dynamic analyses showed that at the end time of expiratory,the CO2 residual concentration below the nostrils is close to 4%.To improve the therapeutic effect,we changed the position of the exhaust holes and found that by moving the exhaust holes to the bottom of the ventilator mask,the CO2 residual concentration below the nostrils would be reduced to no more than 1%.This study established a near physiological computational model and provided a new method for the individualized design of the commercial ventilator mask.展开更多
Two clinical ablation protocols, 2C3L and stepwise, have been routinely used in our group to treat atrial fibrillation （AF）, but with a less than 60% long-term arrhythmia-free outcome achieved in patients. The goal ...Two clinical ablation protocols, 2C3L and stepwise, have been routinely used in our group to treat atrial fibrillation （AF）, but with a less than 60% long-term arrhythmia-free outcome achieved in patients. The goal of this study was to examine the underlying mechanism of low success in clinical outcome. MRI images from one patient were used to reconstruct a human atrial anatomical model, and fibrotic tissue was manually added to represent the arrhythmia substrate. AF was induced with standard protocols used in clinical practice. 2C3L and stepwise were then used to test the efficacy of arrhythmia termination in our model. The results showed that re-entries induced in our model could not be terminated by using either 2C3L or the stepwise protocol. Although some of the induced re-entries were terminated, others emerged in new areas. Ablation using only the 2C3L or stepwise method was not sufficient to terminate all re-entries in our model, which may partially explain the poor long-term arrhythmiafree outcomes in clinical practice. Our findings also suggest that computational heart modelling is an important tool to assist in the establishment of optimal ablation strategies.展开更多
Dear Editor,Mitochondria acts as a cellular organelle that produces ATP and buffers Ca2+,and plays an important role in neuronal growth,survival and function[1].Loss of mitochondria will make the ATP supply insufficie...Dear Editor,Mitochondria acts as a cellular organelle that produces ATP and buffers Ca2+,and plays an important role in neuronal growth,survival and function[1].Loss of mitochondria will make the ATP supply insufficient,resulting in synaptic transmission dysfunction[2].Further,presynaptic mitochondrial dysfunctions are often associated with severe neurological diseases[3].Abnormal mitochondrial function can also lead to neurodegenerative diseases because of the degeneration of synapse transmission,such as Alzheimer’s disease[4]and Parkinson’s disease[5].In neurons,mitochondria have a wide range of size,shape and number,which can be constantly changed through fission and fusion events to form a highly dynamic and organized network[6]and also a way of mitochondrial quality control.展开更多
The main chemical composition of pyrolysis carbon black of waste tires is C,O,Cu,Zn and so on.The content of ash and fine powder in pyrolysis carbon black is high,and the 300%elongation stress is high.The difference b...The main chemical composition of pyrolysis carbon black of waste tires is C,O,Cu,Zn and so on.The content of ash and fine powder in pyrolysis carbon black is high,and the 300%elongation stress is high.The difference between pyrolysis carbon black and furnace black N326,which is commonly used in rubber,is obvious compared with chemical property.The pyrolysis carbon black was used to replace furnace black N326 in the transition layer of all steel load Radial tire rubber through experimental study.It was found that the compression heat generation and dynamic loss(Tanδ)of the blend rubber before and after aging were obviously reduced,the elongation at break and resilience increased,while the tensile stress and tear strength decreased by 100%and 300%,but the hardness and tensile strength changed little before and after aging.According to the latest raw material price calculation,15 used tire pyrolysis carbon black instead of furnace carbon black N326 used in all steel Radial tire transition layer rubber application,excluding labor costs,electricity and equipment depreciation,a ton of blended rubber saves about$22.86 in production costs.展开更多
Introduction Primary cilium is a non-motile microstructure,protruding from cell surface of most mammalian cells.It was previously thought to be vestigial.However,recent studies indicate that it may serve as one of the...Introduction Primary cilium is a non-motile microstructure,protruding from cell surface of most mammalian cells.It was previously thought to be vestigial.However,recent studies indicate that it may serve as one of the most vital mechanosensors for many types of cells such as epithelial and endothelial cells and osteocytes.Protruding from the apical membrane,the primary cilium can directly sense subtle variation of mechanical forces exerted on the cell and then transduce the mechanical cues into biochemical signals into the cell,although the mechanism remain elusive.Vascular endothelial cells(ECs)lining the inner wall of our blood vessels are continuously exposed to the blood flow.In order to maintain proper functions for the cardiovascular system,ECs should have a variety of mechano-sensors and transducers to sense the blood flow change and adjust the vessel size and transport across the vessel wall accordingly.Among more than a dozen recognized EC mechano-sensors,the primary cilium has drawn more and more attention recently.Primary cilium on endothelial cells is essential for the homeostasis of vessels.It is reported to be prevalent in areas of disturbed flow where atherosclerosis and intracranial aneurysm usually occur.Deficiencies of primary cilia may promote atherosclerosis,endothelial-to-mesenchymal transition(EndoMT)and loss of direction orientation,to name a few.Therefore understanding why the primary cilia are necessary to maintain the homeostasis of blood vessels and how will help us develop better treatment strategies for the common cardiovascular diseases.Dimension and structure of primary cilium Primary cilium is reported to be shorter than 8 in length and about 0.2 in diameter.The length of primary cilium varies in different cell types and under different conditions.The major structural components of the primary cilium include basal body,ciliary axoneme(consisting of nine doublet microtubules),ciliary membrane,transition zone,basal feet,and striated rootlets.Each part of the primary cilium is essential and has specific function.Current methods investigating the EC primary cilium as a mechano-sensor:Immunostaining and imaging techniques have been used to investigate the molecular mechanisms by which EC primary cilium serves as a mechano-sensor and transducer.It has been found that various proteins locate on the primary cilium,working together to maintain the function of primary cilium.Some proteins function as ion-channels,mediating Ca2+entry into the primary cilium.Some are involved in the cascade signal pathway.Others are related to the assembly and maintenance of primary cilium.Briefly,the flow induces the deflection of the EC primary cilium,which triggers calcium increase via opening of the PC2 cation channel that is responsible for calcium ion influx.This PC2 cation channel is localized to the primary cilium and is assumed to be stretch-activated.The resulting change in the intracellular calcium concentration then regulates numerous molecular activities inside the cell that contribute to vessel homeostasis.In addition to triggering calcium release,another mechanism has also been found in blood-pressure maintenance in the vasculature,where the vessel diameter is regulated by endothelial primary cilia through adjusting nitric oxide production.So far,little is known about the mechanical mechanism behind this deflection-triggered o-pening of signaling pathways.For example,what is the flow induced bending behavior and force distribution? What is the threshold value of stretch/defection for activating a corresponding signaling pathway? These all remain to be answered.In combination of image data and experiments,several computational models have been established to answer these questions.However,the current models are not able to include the complex structure of primary cilium and the model predictions are limited.Future studies With the development of super high resolution optical microscopy,more detailed images for the structural(molecular)components of EC primary cilia will be revealed,especially when the ECs are alive and the forces are known.Combining these experimental observations with more sophisticated mathematical models will elucidate the mechano-sensing mechanism of EC primary cilia,as the force and stress distribution on cilium along with other mechanical properties are still beyond the capability of experimental approaches due to the scales of the quantities involved.By using numerical approaches,much more detailed dynamic information can be obtained.展开更多
Objective: The aim of this study was to improve the Chinese Daoyin technique (physical and breathing exercises), which is an ancient rehabilitation method, to elevate its effect and to standardize its operational proc...Objective: The aim of this study was to improve the Chinese Daoyin technique (physical and breathing exercises), which is an ancient rehabilitation method, to elevate its effect and to standardize its operational procedure. Methods: Based on the ancient Chinese Daoyin technique, a six-step method was developed including: 1) motion imagination and imitation;2) mental and breathing regulation;3) target point determination;4) motion percussion;5) motion persistence;6) relaxation. Sixty drop-foot patients who suffered from hemiparesis after a stroke were randomly divided into the experimental group and the control group. Functional evaluation including Fugl-Meyer assessment score, Lovett manual muscle test (MMT), active range of motion of the ankle joint and electromyography were performed before and after the training course. The data were analyzed using the statistical software SPSS 12.0. Results: The differences between the two groups were significant. The effectiveness of the six-step group was significantly better than the effectiveness of the control group. Conclusion: The six-step method of the Chinese Daoyin technique is an effective rehabilitation training method for drop-foot in stroke patients with hemiparesis.展开更多
Magnesium alloys have gained great attention as biodegradable materials for stent applications.Cardiovascular stents are continuously exposed to different types of mechanical loadings simultaneously during service,inc...Magnesium alloys have gained great attention as biodegradable materials for stent applications.Cardiovascular stents are continuously exposed to different types of mechanical loadings simultaneously during service,including tensile,compressive and fluid shear stress.In this study,the in vitro degradation of WE43 wires was investigated under combined effect of tensile loading and fluid shear stress and compared with that experienced an individual loading condition.For the individual mechanical loading treatment,the degradation of magnesium wires was more severely affected by tensile loading than fluid shear stress.Under tensile loading,magnesium wires showed faster increment of corrosion rates,loss of mechanical properties and localized corrosion morphology with the increasing tensile loadings.With the combined stress,smaller variation of the corrosion rates as well as the slower strength degeneration was shown with increasing stress levels,in comparison with the individual treatment of tensile loading.This study could help to understand the effect of complex stress condition on the corrosion of magnesium for the optimization of biodegradable magnesium stents.展开更多
Functional near-infrared spectroscopy(fNIRS)has gained great interest as a noninvasive modality to study the changes in cerebral hemodynamics related to brain activity.The unique and beneficial characteristics of fNIR...Functional near-infrared spectroscopy(fNIRS)has gained great interest as a noninvasive modality to study the changes in cerebral hemodynamics related to brain activity.The unique and beneficial characteristics of fNIRS allow ecologically effective investigations of all ages and conditions in more realistic and clinical environments.In this review,we provide a comprehensive description of fNIRS basics,analytical method developments and applications in stroke rehabilitation.We first review various new methods for the time-series processing and functional analysis of fNIRS data.Then,we review the fNIRS-based application in clinical research for stroke rehabilitation and highlight the exciting developments based on fNIRS.Finally,we discuss the possible technical limitations of the implementation of fNIRS and provide suggestions from different aspects for practical application.展开更多
Development of viable cell estimation method without sacrificing proliferation and functions of cells cultured on regenerative biomaterials is essential for regenerative engineering.Cytotoxicity and depletion of resaz...Development of viable cell estimation method without sacrificing proliferation and functions of cells cultured on regenerative biomaterials is essential for regenerative engineering.Cytotoxicity and depletion of resazurin are critical but often overlooked limitations that hindered applications of resazurin in viable cell estimation.The present work found that cytotoxicity and depletion of resazurin depended on cell concentration,resazurin concentration and resazurin incubation time.A simple strategy which only allowed cells to incubate with resazurin during each measurement was developed to eliminate negative effects of resazurin.This strategy was verified by monitoring proliferation of MC3T3-E1 preosteoblasts on poly(D,L-lactic acid)scaffold during a continuous 3D culture process for up to 21 days,comparing the accuracy with MTT assay which is a destructive assay with high sensitivity and accuracy and commonly used in regenerative engineering and comparing viability,proliferation and differentiation functions of MC3T3-E1,which were treated with/without this strategy for nondestructive evaluation.This method showed comparable linearity of standard curve and characteristics of growth curve to MTT assay.No major negative effects of this method on MC3T3-E1 viability and functions were found.Our work highlighted the importance of the concentration and incubation time of resazurin in designing application-specific nondestructive viability assay and would be helpful in improving the implanted medical devices as well as in regenerative engineering.展开更多
Traditional Chinese Medicine(TCM)has played crucial roles in treating COVID-19 in China.But its effectiveness has not yet been widely realized/recognized over the world.We performed a systematic review and meta-analys...Traditional Chinese Medicine(TCM)has played crucial roles in treating COVID-19 in China.But its effectiveness has not yet been widely realized/recognized over the world.We performed a systematic review and meta-analysis to investigate the clinical efficacy of TCM medicine in the treatment for COVID-19.We obtained the data of COVID-19 and traditional Chinese medicine from PubMed,MEDLINE,Web of Science and other databases,and searched from January 1,2020 to January 26,2022 to determine the randomized controlled trials(RCTs)without language restrictions.The review includes 26 randomized clinical trials including 2981 patients.The treatment of COVID-19 by TCM combined with conventional treatment is more effective than by pure conventional treatment in many aspects,including increasing of the effective rate[OR=2.47,95%CI(1.85,3.30),P<0.00001],fever disappearance rate[OR=3.68,95%CI(1.95,6.96),P<0.0001],fatigue disappearance rate[OR=3.15,95%CI(1.60,6.21),P=0.0009],cough disappearance rate[OR=2.89,95%CI(1.84,4.54),P<0.00001],expectoration disappearance rate[OR=5.94,95%CI(1.98,17.84),P=0.001],disappearance rate of shortness of breath[OR=2.57,95%CI(1.13,5.80),P=0.02],improvement rate of CT image[OR=2.43,95%CI(1.86,3.16),P<0.00001],and reduction of the hospitalization time[MD=3.16,95%CI(3.75,2.56),P<0.00001],and deterioration rate[OR=0.49,95%CI(0.29,0.83),P=0.007].The findings of this meta-analysis suggest that TCM can effectively relieve symptoms,boosted patients' recovery,cut the rate of patients developing into severe conditions,and reduce the deterioration rate.展开更多
Magnesium alloys with integration of degradability and good mechanical performance are desired for orthopedic implants.In this paper,Mg-2Sr-Ca and Mg-2Sr-Zn alloys were prepared and the degradation as well as the bone...Magnesium alloys with integration of degradability and good mechanical performance are desired for orthopedic implants.In this paper,Mg-2Sr-Ca and Mg-2Sr-Zn alloys were prepared and the degradation as well as the bone response were investigated.Compared with the binary Mg-2Sr alloys,the addition of Ca and Zn improved the in vitro and in vivo corrosion resistance.Mg-2Sr-Ca and Mg-2Sr-Zn alloys exhibited more uniform corrosion and maintained the configuration of the implants 4 weeks post-implantation.The in vivo corrosion rates were 0.85 mm/yr for Mg-2Sr-Zn and 1.10 mm/yr for Mg-2Sr-Ca in comparison with 1.37 mm/yr for Mg-2Sr.The in vitro cell tests indicated that Mg-2Sr-Ca and Mg-2Sr-Zn alloys exhibited higher MG63 cell viability than Mg-2Sr alloy.Furthermore,these two alloys can promote the mineralization and new bone formation without inducing any significant adverse effects and this sound osteogenic properties suggest its attractive clinical potential.展开更多
Magnesium alloys have shown prospective applications as a new biodegradable metal within bone. To garantee the longterm biocompatibility, a Mg-Zn-Ca alloy,composing of essential elements for human, was prepared and it...Magnesium alloys have shown prospective applications as a new biodegradable metal within bone. To garantee the longterm biocompatibility, a Mg-Zn-Ca alloy,composing of essential elements for human, was prepared and its feasibility for orthopedic applications was investigated. The in vitro and in vivo corrosion of Mg-Zn-Ca alloy as well as the biocompatibility were studied. The in vitro corrosion tests in five kinds of physiological solutions showed that the corrosion rates and corrosion morphologies of the alloy were strongly influenced by the solution used. The addition of serum in Hank’s and MEM significantly slowed down the corrosion rate and improved the corrosion uniformity of the alloy. The corrosion rate decreased with increasing serum concentration.The alloy showed the slowest corrosion rate as well as homogeneous corrosion morphology in MEM＋10%FBS. Both the indirect and direct cell experiments indicated good cytocompatibility of the extruded Mg-Zn-Ca alloy. In vivo, we observed a gradual degradation process from the surface of extruded Mg-Zn-Ca alloy and only 40% in volume of implant was left after 4 weeks implantation in medullary cavities of mice. The micro-CT and histological analyses revealed its good biocompatibility with peri-implant new bone formation and increasing cortical bone thickness with increasing implantation period. This study showed that the extruded MgZn-Ca alloy provided sufficient biocompatibility for orthopedic application, though the in vivo corrosion rate should be further reduced for clinical use.展开更多
Electron beam melting(EBM) allows the fabrication of specific porous titanium implants, whereas their in vitro and in vivo biological performance should be further investigated. In this study, we examined the porous T...Electron beam melting(EBM) allows the fabrication of specific porous titanium implants, whereas their in vitro and in vivo biological performance should be further investigated. In this study, we examined the porous Ti6 Al4 V scaffolds(low, 334.1 μm pore size with 55.4% porosity;middle, 383.2 μm pore size with 65.2% porosity;and high, 401.6 μm pore size with 78.1%porosity) fabricated through EBM. The structural characterization and mechanical properties of porous Ti6 Al4 V scaffolds were measured through micro-computed tomography(micro-CT), scanning electron microscopy, and a material testing system.MC3 T3-E1 cells were used to assess the proliferation and differentiation of the cells on different scaffolds at day 7 and day 14 based on the expression levels of genes, including alkaline phosphatase, bone morphogenetic protein-2, osteopontin and runtrelated transcription factor-2. Rabbits with distal femoral defects were utilized to evaluate bone ingrowth in the porous titanium.All of the samples were subjected to micro-CT and histological analysis after 12 weeks. Results showed that compressive Young’s modulus of 0.3–1.1 GPa was similar to the trabecular bone. The three types of porous Ti6 Al4 V scaffolds were inclined to promote cell proliferation, whereas cell differentiation and bone ingrowth into the porous scaffolds were biased to the porous titanium with relatively large pores and porosity(middle and high). This study implied that the present porous implant design,which had the combined advantages of different pore sizes and porosity, might be meaningful and promising for trabecular bone defect restoration.展开更多
The present study aimed to investigate the effect of an auricular acupuncture intervention on the relationship between changes in oxyhemoglobin concentration(Δ[O2Hb])and arterial blood pressure(ABP).The cerebral oxyg...The present study aimed to investigate the effect of an auricular acupuncture intervention on the relationship between changes in oxyhemoglobin concentration(Δ[O2Hb])and arterial blood pressure(ABP).The cerebral oxygenation signals in the bilateral prefrontal cortex(PFC),sensorimotor cortex(SMC),and temporal lobe cortex(TLC)of 15 patients with hypertension were measured by a 24-channel functional near-infrared spectroscopy(fNIRS)device before(State_R)and after(State_AT)the auricular acupuncture intervention.Coupling strength was used to quantitatively evaluate the strength of the couplings between ABP andΔ[O2Hb]in low-frequency oscillations(LF,0.07–0.2 Hz)and very-low-frequency oscillations(VLF,0.02–0.07 Hz).Results showed that the changes in wavelet amplitudes in the LF and VLF intervals did not exhibit significant differences after auricular acupuncture.The coupling strength from ABP toΔ[O2Hb]was significantly lower in the LF range after auricular acupuncture in the bilateral PFC,SMC,and TLC(p<0.0083).Additionally,the coupling strength from ABP toΔ[O2Hb]in the VLF range was significantly lower in the bilateral PFC in State_AT than in State_R(p<0.0083).These results indicated that fNIRS together with ABP can effectively evaluate cerebral hemodynamic responses to interventions and is therefore capable of guiding more individualized acupuncture strategies.The auricular acupuncture intervention improved hemodynamic responses in patients suffering from hypertension.展开更多
Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury.In addition,mechanical stretch at high displacement rates of 10%tensile strain can cause marked nerve injury,it is im...Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury.In addition,mechanical stretch at high displacement rates of 10%tensile strain can cause marked nerve injury,it is important for finding a proper nano biomaterial to repair nerve injury.Nano-hydroxyapatite(n-HA)has excellent biocompatibility and high bioactivity,which is a good candidate for biomedical engineering applications.But the certain mechanism of n-HA on the injured nerve is seldom reported.In this study,we determined the role of n-HA on the mechanical stretch-induced nerve injury at adult rat spine.Mechanical stretch under strain 10%at displacement rates of 60 mm/min can cause marked broken vessels and edema in spinal cord and dorsal root ganglion tissue in haematoxylin-eosin(HE)staining.However,n-HA application can reverse hemorrhage and edema triggered by high rates of 60 mm/min stretch.Moreover,n-HA can promote positive staining of Netrin-1 increase significantly in spinal cord and dorsal root ganglion tested by immunohistochemistry(IHC)staining.In general,our study indicated that n-HA can repair mechanical stretch-induced nerve injury,it may provide a new approach to block injury and accelerate nerve regeneration in future.展开更多
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.
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Supported by National Natural Science Foundation of China(Grant No.61273342)Beijing Municipal Natural Science Foundation of China(Grant Nos.3113026,3132005)
文摘Due to the close physical interaction between human and machine in process of gait training, lower limb exoskeletons should be safe, comfortable and able to smoothly transfer desired driving force/moments to the patients. Correlatively, in kinematics the exoskeletons are required to be compatible with human lower limbs and thereby to avoid the uncontrollable interactional loads at the human-machine interfaces. Such requirement makes the structure design of exoskeletons very difficult because the human-machine closed chains are complicated. In addition, both the axis misalignments and the kinematic character difference between the exoskeleton and human joints should be taken into account. By analyzing the DOF（degree of freedom） of the whole human-machine closed chain, the human-machine kinematic incompatibility of lower limb exoskeletons is studied. An effective method for the structure design of lower limb exoskeletons, which are kinematically compatible with human lower limb, is proposed. Applying this method, the structure synthesis of the lower limb exoskeletons containing only one-DOF revolute and prismatic joints is investigated; the feasible basic structures of exoskeletons are developed and classified into three different categories. With the consideration of quasi-anthropopathic feature, structural simplicity and wearable comfort of lower limb exoskeletons, a joint replacement and structure comparison based approach to select the ideal structures of lower limb exoskeletons is proposed, by which three optimal exoskeleton structures are obtained. This paper indicates that the human-machine closed chain formed by the exoskeleton and human lower limb should be an even-constrained kinematic system in order to avoid the uncontrollable human-machine interactional loads. The presented method for the structure design of lower limb exoskeletons is universal and simple, and hence can be applied to other kinds of wearable exoskeletons.
基金Supported by National Natural Science Foundation of China(Grant Nos.51005133,51375009)National Hi-tech Research and Development Program of China(863 Program,Grant No.2011AA11A244)
文摘The existing research of steering comfort mainly focuses on the subjective evaluation,aiming at designing and optimizing the steering system.In the development of steering system,especially the evaluation of steering comfort,the objective evaluation methods considered the kinematic characteristics of driver steering maneuver are not proposed,which means that the objective evaluation of steering cannot be conducted with the evaluation of kinematic characteristics of driver in steering maneuver.In order to propose the objective evaluation methods of steering comfort,the evaluation of steering movement quality of driver is developed on the basis of the study of the kinematic characteristics of steering maneuver.First,the steering motion trajectories of the driver in both comfortable and certain extreme uncomfortable operation conditions are detected using the Vicon motion capture system.The operation conditions are under the restrictions of the vertical height and horizontal distance between steering wheel center and the H-point of driver,and the steering resisting torque else.Next,the movement quality evaluation of driver steering maneuver is assessed using twelve kinds of evaluation indices based on the kinematic analyses of the steering motion trajectories to propose an objective evaluation method.Finally,an integrated discomfort index of steering maneuver is proposed on the basis of the regression analysis of subjective evaluation rating and the movement quality evaluation indices,including the Jerk,Discomfort and Joint Torque indices.The test results show that the proposed integrated discomfort index gives a good fitting with the subjective evaluation of discomfort,which means it can be used to evaluate or predict the discomfort level of steering maneuver.This paper proposes an objective evaluation method of steering comfort based on the movement quality evaluation of driver steering maneuver.
基金We acknowledge the National Natural Science Foundation of China for supporting the project via the grant number 11472062 and 11002034.
文摘OSAHS(Obstructive Sleep Apnea Hypopnea Syndrome)is a respiratory disease mainly characterized by limited and repeated pauses of breathing in sleep.Currently,the optimal treatment is to apply CPAP(Continuous Positive Airway Pressure)ventilation on the upper airway of the patient through a household respiratory machine.However,if the ventilator mask is designed improperly,it might cause the residue and repeated inhalation of CO2,which will exert an adverse impact on the therapeutic effect.Present research numerically analyzed the CO2 transportation inside a commercial ventilator mask(Mirage SoftGel,ResMed,Australia)based on the reconstructed 3D numerical model of a volunteer's face and performed the improved design of the ventilator mask in terms of the CO2 residual concentration below the nostrils.The fluid dynamic analyses showed that at the end time of expiratory,the CO2 residual concentration below the nostrils is close to 4%.To improve the therapeutic effect,we changed the position of the exhaust holes and found that by moving the exhaust holes to the bottom of the ventilator mask,the CO2 residual concentration below the nostrils would be reduced to no more than 1%.This study established a near physiological computational model and provided a new method for the individualized design of the commercial ventilator mask.
基金The work was supported by the CAMS Fund of the Nonprofit Central Research Institutes （No. 2016ZX330015）, National Natural Science Foundation of China （No. 11421202） and the 111 Project （No. B13003）.
文摘Two clinical ablation protocols, 2C3L and stepwise, have been routinely used in our group to treat atrial fibrillation （AF）, but with a less than 60% long-term arrhythmia-free outcome achieved in patients. The goal of this study was to examine the underlying mechanism of low success in clinical outcome. MRI images from one patient were used to reconstruct a human atrial anatomical model, and fibrotic tissue was manually added to represent the arrhythmia substrate. AF was induced with standard protocols used in clinical practice. 2C3L and stepwise were then used to test the efficacy of arrhythmia termination in our model. The results showed that re-entries induced in our model could not be terminated by using either 2C3L or the stepwise protocol. Although some of the induced re-entries were terminated, others emerged in new areas. Ablation using only the 2C3L or stepwise method was not sufficient to terminate all re-entries in our model, which may partially explain the poor long-term arrhythmiafree outcomes in clinical practice. Our findings also suggest that computational heart modelling is an important tool to assist in the establishment of optimal ablation strategies.
基金the National Key Research and Development Program of China(2017YFA0504700)The National Natural Science Foundation of China(32027901).
文摘Dear Editor,Mitochondria acts as a cellular organelle that produces ATP and buffers Ca2+,and plays an important role in neuronal growth,survival and function[1].Loss of mitochondria will make the ATP supply insufficient,resulting in synaptic transmission dysfunction[2].Further,presynaptic mitochondrial dysfunctions are often associated with severe neurological diseases[3].Abnormal mitochondrial function can also lead to neurodegenerative diseases because of the degeneration of synapse transmission,such as Alzheimer’s disease[4]and Parkinson’s disease[5].In neurons,mitochondria have a wide range of size,shape and number,which can be constantly changed through fission and fusion events to form a highly dynamic and organized network[6]and also a way of mitochondrial quality control.
文摘The main chemical composition of pyrolysis carbon black of waste tires is C,O,Cu,Zn and so on.The content of ash and fine powder in pyrolysis carbon black is high,and the 300%elongation stress is high.The difference between pyrolysis carbon black and furnace black N326,which is commonly used in rubber,is obvious compared with chemical property.The pyrolysis carbon black was used to replace furnace black N326 in the transition layer of all steel load Radial tire rubber through experimental study.It was found that the compression heat generation and dynamic loss(Tanδ)of the blend rubber before and after aging were obviously reduced,the elongation at break and resilience increased,while the tensile stress and tear strength decreased by 100%and 300%,but the hardness and tensile strength changed little before and after aging.According to the latest raw material price calculation,15 used tire pyrolysis carbon black instead of furnace carbon black N326 used in all steel Radial tire transition layer rubber application,excluding labor costs,electricity and equipment depreciation,a ton of blended rubber saves about$22.86 in production costs.
基金supported by grants ( 11421202,11572029) from National Natural Science Foundation of China
文摘Introduction Primary cilium is a non-motile microstructure,protruding from cell surface of most mammalian cells.It was previously thought to be vestigial.However,recent studies indicate that it may serve as one of the most vital mechanosensors for many types of cells such as epithelial and endothelial cells and osteocytes.Protruding from the apical membrane,the primary cilium can directly sense subtle variation of mechanical forces exerted on the cell and then transduce the mechanical cues into biochemical signals into the cell,although the mechanism remain elusive.Vascular endothelial cells(ECs)lining the inner wall of our blood vessels are continuously exposed to the blood flow.In order to maintain proper functions for the cardiovascular system,ECs should have a variety of mechano-sensors and transducers to sense the blood flow change and adjust the vessel size and transport across the vessel wall accordingly.Among more than a dozen recognized EC mechano-sensors,the primary cilium has drawn more and more attention recently.Primary cilium on endothelial cells is essential for the homeostasis of vessels.It is reported to be prevalent in areas of disturbed flow where atherosclerosis and intracranial aneurysm usually occur.Deficiencies of primary cilia may promote atherosclerosis,endothelial-to-mesenchymal transition(EndoMT)and loss of direction orientation,to name a few.Therefore understanding why the primary cilia are necessary to maintain the homeostasis of blood vessels and how will help us develop better treatment strategies for the common cardiovascular diseases.Dimension and structure of primary cilium Primary cilium is reported to be shorter than 8 in length and about 0.2 in diameter.The length of primary cilium varies in different cell types and under different conditions.The major structural components of the primary cilium include basal body,ciliary axoneme(consisting of nine doublet microtubules),ciliary membrane,transition zone,basal feet,and striated rootlets.Each part of the primary cilium is essential and has specific function.Current methods investigating the EC primary cilium as a mechano-sensor:Immunostaining and imaging techniques have been used to investigate the molecular mechanisms by which EC primary cilium serves as a mechano-sensor and transducer.It has been found that various proteins locate on the primary cilium,working together to maintain the function of primary cilium.Some proteins function as ion-channels,mediating Ca2+entry into the primary cilium.Some are involved in the cascade signal pathway.Others are related to the assembly and maintenance of primary cilium.Briefly,the flow induces the deflection of the EC primary cilium,which triggers calcium increase via opening of the PC2 cation channel that is responsible for calcium ion influx.This PC2 cation channel is localized to the primary cilium and is assumed to be stretch-activated.The resulting change in the intracellular calcium concentration then regulates numerous molecular activities inside the cell that contribute to vessel homeostasis.In addition to triggering calcium release,another mechanism has also been found in blood-pressure maintenance in the vasculature,where the vessel diameter is regulated by endothelial primary cilia through adjusting nitric oxide production.So far,little is known about the mechanical mechanism behind this deflection-triggered o-pening of signaling pathways.For example,what is the flow induced bending behavior and force distribution? What is the threshold value of stretch/defection for activating a corresponding signaling pathway? These all remain to be answered.In combination of image data and experiments,several computational models have been established to answer these questions.However,the current models are not able to include the complex structure of primary cilium and the model predictions are limited.Future studies With the development of super high resolution optical microscopy,more detailed images for the structural(molecular)components of EC primary cilia will be revealed,especially when the ECs are alive and the forces are known.Combining these experimental observations with more sophisticated mathematical models will elucidate the mechano-sensing mechanism of EC primary cilia,as the force and stress distribution on cilium along with other mechanical properties are still beyond the capability of experimental approaches due to the scales of the quantities involved.By using numerical approaches,much more detailed dynamic information can be obtained.
文摘Objective: The aim of this study was to improve the Chinese Daoyin technique (physical and breathing exercises), which is an ancient rehabilitation method, to elevate its effect and to standardize its operational procedure. Methods: Based on the ancient Chinese Daoyin technique, a six-step method was developed including: 1) motion imagination and imitation;2) mental and breathing regulation;3) target point determination;4) motion percussion;5) motion persistence;6) relaxation. Sixty drop-foot patients who suffered from hemiparesis after a stroke were randomly divided into the experimental group and the control group. Functional evaluation including Fugl-Meyer assessment score, Lovett manual muscle test (MMT), active range of motion of the ankle joint and electromyography were performed before and after the training course. The data were analyzed using the statistical software SPSS 12.0. Results: The differences between the two groups were significant. The effectiveness of the six-step group was significantly better than the effectiveness of the control group. Conclusion: The six-step method of the Chinese Daoyin technique is an effective rehabilitation training method for drop-foot in stroke patients with hemiparesis.
基金This work was supported by National Natural Science Foundation of China(NSFC,51401007,11472032)A Foundation for the Author of National Excellent Doctoral Dissertation of PR China(201463)+1 种基金Young Elite Scientists Sponsorship Program By CAST(2017QNRC001)The National Key Research and Development Plan(2016YFC1102203,2016YFC1101100,2018YFC1106600).
文摘Magnesium alloys have gained great attention as biodegradable materials for stent applications.Cardiovascular stents are continuously exposed to different types of mechanical loadings simultaneously during service,including tensile,compressive and fluid shear stress.In this study,the in vitro degradation of WE43 wires was investigated under combined effect of tensile loading and fluid shear stress and compared with that experienced an individual loading condition.For the individual mechanical loading treatment,the degradation of magnesium wires was more severely affected by tensile loading than fluid shear stress.Under tensile loading,magnesium wires showed faster increment of corrosion rates,loss of mechanical properties and localized corrosion morphology with the increasing tensile loadings.With the combined stress,smaller variation of the corrosion rates as well as the slower strength degeneration was shown with increasing stress levels,in comparison with the individual treatment of tensile loading.This study could help to understand the effect of complex stress condition on the corrosion of magnesium for the optimization of biodegradable magnesium stents.
基金This work was supported by the National Key Research and Development Project Nos.(Grant No.2020YFC2004200)National Natural Science Foundation of China(Grant No.31771071,61761166007)the Fundamental Research Funds for Central Public Welfare Research Institutes(118009001000160001).
文摘Functional near-infrared spectroscopy(fNIRS)has gained great interest as a noninvasive modality to study the changes in cerebral hemodynamics related to brain activity.The unique and beneficial characteristics of fNIRS allow ecologically effective investigations of all ages and conditions in more realistic and clinical environments.In this review,we provide a comprehensive description of fNIRS basics,analytical method developments and applications in stroke rehabilitation.We first review various new methods for the time-series processing and functional analysis of fNIRS data.Then,we review the fNIRS-based application in clinical research for stroke rehabilitation and highlight the exciting developments based on fNIRS.Finally,we discuss the possible technical limitations of the implementation of fNIRS and provide suggestions from different aspects for practical application.
基金supported by the National Natural Science Foundation of China(31771019,11172031,11827803,and 31470901)The National Key Research and Development Plan(2016YFC1101101)International Joint Research Center of Aerospace Biotechnology and 344 Medical Engineering from Ministry of Science and Technology of China,111 Project 345(B13003).
文摘Development of viable cell estimation method without sacrificing proliferation and functions of cells cultured on regenerative biomaterials is essential for regenerative engineering.Cytotoxicity and depletion of resazurin are critical but often overlooked limitations that hindered applications of resazurin in viable cell estimation.The present work found that cytotoxicity and depletion of resazurin depended on cell concentration,resazurin concentration and resazurin incubation time.A simple strategy which only allowed cells to incubate with resazurin during each measurement was developed to eliminate negative effects of resazurin.This strategy was verified by monitoring proliferation of MC3T3-E1 preosteoblasts on poly(D,L-lactic acid)scaffold during a continuous 3D culture process for up to 21 days,comparing the accuracy with MTT assay which is a destructive assay with high sensitivity and accuracy and commonly used in regenerative engineering and comparing viability,proliferation and differentiation functions of MC3T3-E1,which were treated with/without this strategy for nondestructive evaluation.This method showed comparable linearity of standard curve and characteristics of growth curve to MTT assay.No major negative effects of this method on MC3T3-E1 viability and functions were found.Our work highlighted the importance of the concentration and incubation time of resazurin in designing application-specific nondestructive viability assay and would be helpful in improving the implanted medical devices as well as in regenerative engineering.
基金the National Natural Science Foundation of China(Grant No.11932017,11772055,11532009,and 11521062).
文摘Traditional Chinese Medicine(TCM)has played crucial roles in treating COVID-19 in China.But its effectiveness has not yet been widely realized/recognized over the world.We performed a systematic review and meta-analysis to investigate the clinical efficacy of TCM medicine in the treatment for COVID-19.We obtained the data of COVID-19 and traditional Chinese medicine from PubMed,MEDLINE,Web of Science and other databases,and searched from January 1,2020 to January 26,2022 to determine the randomized controlled trials(RCTs)without language restrictions.The review includes 26 randomized clinical trials including 2981 patients.The treatment of COVID-19 by TCM combined with conventional treatment is more effective than by pure conventional treatment in many aspects,including increasing of the effective rate[OR=2.47,95%CI(1.85,3.30),P<0.00001],fever disappearance rate[OR=3.68,95%CI(1.95,6.96),P<0.0001],fatigue disappearance rate[OR=3.15,95%CI(1.60,6.21),P=0.0009],cough disappearance rate[OR=2.89,95%CI(1.84,4.54),P<0.00001],expectoration disappearance rate[OR=5.94,95%CI(1.98,17.84),P=0.001],disappearance rate of shortness of breath[OR=2.57,95%CI(1.13,5.80),P=0.02],improvement rate of CT image[OR=2.43,95%CI(1.86,3.16),P<0.00001],and reduction of the hospitalization time[MD=3.16,95%CI(3.75,2.56),P<0.00001],and deterioration rate[OR=0.49,95%CI(0.29,0.83),P=0.007].The findings of this meta-analysis suggest that TCM can effectively relieve symptoms,boosted patients' recovery,cut the rate of patients developing into severe conditions,and reduce the deterioration rate.
基金supported by the National Key R&D Program of China(2018YFC1106600)A Foundation for the Author of National Excellent Doctoral Dissertation of PR China(201463)+2 种基金Young Elite Scientists Sponsorship Program By CAST(2017QNRC001)Beijing Natural Science Foundation(2192027)the National Natural Science Foundation of China(81572109).
文摘Magnesium alloys with integration of degradability and good mechanical performance are desired for orthopedic implants.In this paper,Mg-2Sr-Ca and Mg-2Sr-Zn alloys were prepared and the degradation as well as the bone response were investigated.Compared with the binary Mg-2Sr alloys,the addition of Ca and Zn improved the in vitro and in vivo corrosion resistance.Mg-2Sr-Ca and Mg-2Sr-Zn alloys exhibited more uniform corrosion and maintained the configuration of the implants 4 weeks post-implantation.The in vivo corrosion rates were 0.85 mm/yr for Mg-2Sr-Zn and 1.10 mm/yr for Mg-2Sr-Ca in comparison with 1.37 mm/yr for Mg-2Sr.The in vitro cell tests indicated that Mg-2Sr-Ca and Mg-2Sr-Zn alloys exhibited higher MG63 cell viability than Mg-2Sr alloy.Furthermore,these two alloys can promote the mineralization and new bone formation without inducing any significant adverse effects and this sound osteogenic properties suggest its attractive clinical potential.
基金supported by the National Natural Science Foundation of China(51401007,11472032,11120101001 and 11421202)a foundation for the author of the National Excellent Doctoral Dissertation of China(201463)+1 种基金Young Elite Scientists Sponsorship Program By CAST(2017QNRC001)the National Key Research and Development Plan(2016YFC1102203 and 2016YFC1101100)
文摘Magnesium alloys have shown prospective applications as a new biodegradable metal within bone. To garantee the longterm biocompatibility, a Mg-Zn-Ca alloy,composing of essential elements for human, was prepared and its feasibility for orthopedic applications was investigated. The in vitro and in vivo corrosion of Mg-Zn-Ca alloy as well as the biocompatibility were studied. The in vitro corrosion tests in five kinds of physiological solutions showed that the corrosion rates and corrosion morphologies of the alloy were strongly influenced by the solution used. The addition of serum in Hank’s and MEM significantly slowed down the corrosion rate and improved the corrosion uniformity of the alloy. The corrosion rate decreased with increasing serum concentration.The alloy showed the slowest corrosion rate as well as homogeneous corrosion morphology in MEM＋10%FBS. Both the indirect and direct cell experiments indicated good cytocompatibility of the extruded Mg-Zn-Ca alloy. In vivo, we observed a gradual degradation process from the surface of extruded Mg-Zn-Ca alloy and only 40% in volume of implant was left after 4 weeks implantation in medullary cavities of mice. The micro-CT and histological analyses revealed its good biocompatibility with peri-implant new bone formation and increasing cortical bone thickness with increasing implantation period. This study showed that the extruded MgZn-Ca alloy provided sufficient biocompatibility for orthopedic application, though the in vivo corrosion rate should be further reduced for clinical use.
基金supported by the China National Key Research and Development Plan Project (Grant No. 2016YFB1101102)Fundamental Research Funds for Central Public Welfare Research Institutes (Grant No. 118009001000160001)
文摘Electron beam melting(EBM) allows the fabrication of specific porous titanium implants, whereas their in vitro and in vivo biological performance should be further investigated. In this study, we examined the porous Ti6 Al4 V scaffolds(low, 334.1 μm pore size with 55.4% porosity;middle, 383.2 μm pore size with 65.2% porosity;and high, 401.6 μm pore size with 78.1%porosity) fabricated through EBM. The structural characterization and mechanical properties of porous Ti6 Al4 V scaffolds were measured through micro-computed tomography(micro-CT), scanning electron microscopy, and a material testing system.MC3 T3-E1 cells were used to assess the proliferation and differentiation of the cells on different scaffolds at day 7 and day 14 based on the expression levels of genes, including alkaline phosphatase, bone morphogenetic protein-2, osteopontin and runtrelated transcription factor-2. Rabbits with distal femoral defects were utilized to evaluate bone ingrowth in the porous titanium.All of the samples were subjected to micro-CT and histological analysis after 12 weeks. Results showed that compressive Young’s modulus of 0.3–1.1 GPa was similar to the trabecular bone. The three types of porous Ti6 Al4 V scaffolds were inclined to promote cell proliferation, whereas cell differentiation and bone ingrowth into the porous scaffolds were biased to the porous titanium with relatively large pores and porosity(middle and high). This study implied that the present porous implant design,which had the combined advantages of different pore sizes and porosity, might be meaningful and promising for trabecular bone defect restoration.
基金This work was supported by the National Key Research and Development Project[grant number 2020YFC2004200]the National Natural Science Foundation of China[grant numbers 31771071,11732015,61675013]+1 种基金the Fundamental Research Funds for Central Public Welfare Research Institutes[grant number 118009001000160001]the Key Research and Development Project of Jiangxi Province[grant number 20202BBGL73057].
文摘The present study aimed to investigate the effect of an auricular acupuncture intervention on the relationship between changes in oxyhemoglobin concentration(Δ[O2Hb])and arterial blood pressure(ABP).The cerebral oxygenation signals in the bilateral prefrontal cortex(PFC),sensorimotor cortex(SMC),and temporal lobe cortex(TLC)of 15 patients with hypertension were measured by a 24-channel functional near-infrared spectroscopy(fNIRS)device before(State_R)and after(State_AT)the auricular acupuncture intervention.Coupling strength was used to quantitatively evaluate the strength of the couplings between ABP andΔ[O2Hb]in low-frequency oscillations(LF,0.07–0.2 Hz)and very-low-frequency oscillations(VLF,0.02–0.07 Hz).Results showed that the changes in wavelet amplitudes in the LF and VLF intervals did not exhibit significant differences after auricular acupuncture.The coupling strength from ABP toΔ[O2Hb]was significantly lower in the LF range after auricular acupuncture in the bilateral PFC,SMC,and TLC(p<0.0083).Additionally,the coupling strength from ABP toΔ[O2Hb]in the VLF range was significantly lower in the bilateral PFC in State_AT than in State_R(p<0.0083).These results indicated that fNIRS together with ABP can effectively evaluate cerebral hemodynamic responses to interventions and is therefore capable of guiding more individualized acupuncture strategies.The auricular acupuncture intervention improved hemodynamic responses in patients suffering from hypertension.
基金supported by funds from the National Natural Science Foundation of China(NSFC)Research Grant(31971238,51574246,61871014,11827803,31771019)National Key Research and Development Program(2016YFC1100704,2016YFC1102203)+1 种基金also supported by 111 Project(B13003)International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology,China.
文摘Damage of axon and glial scars formation both inhibit nerve regenerative growth during nerve injury.In addition,mechanical stretch at high displacement rates of 10%tensile strain can cause marked nerve injury,it is important for finding a proper nano biomaterial to repair nerve injury.Nano-hydroxyapatite(n-HA)has excellent biocompatibility and high bioactivity,which is a good candidate for biomedical engineering applications.But the certain mechanism of n-HA on the injured nerve is seldom reported.In this study,we determined the role of n-HA on the mechanical stretch-induced nerve injury at adult rat spine.Mechanical stretch under strain 10%at displacement rates of 60 mm/min can cause marked broken vessels and edema in spinal cord and dorsal root ganglion tissue in haematoxylin-eosin(HE)staining.However,n-HA application can reverse hemorrhage and edema triggered by high rates of 60 mm/min stretch.Moreover,n-HA can promote positive staining of Netrin-1 increase significantly in spinal cord and dorsal root ganglion tested by immunohistochemistry(IHC)staining.In general,our study indicated that n-HA can repair mechanical stretch-induced nerve injury,it may provide a new approach to block injury and accelerate nerve regeneration in future.
