Morphological analyses are key outcome assessments for nerve regeneration studies but are historically limited to tissue sections.Novel optical tissue clearing techniques enabling three-dimensional imaging of entire o...Morphological analyses are key outcome assessments for nerve regeneration studies but are historically limited to tissue sections.Novel optical tissue clearing techniques enabling three-dimensional imaging of entire organs at a subcellular resolution have revolutionized morphological studies of the brain.To extend their applicability to experimental nerve repair studies we adapted these techniques to nerves and their motor and sensory targets in rats.The solvent-based protocols rendered harvested peripheral nerves and their target organs transparent within 24 hours while preserving tissue architecture and fluorescence.The optical clearing was compatible with conventional laboratory techniques,including retrograde labeling studies,and computational image segmentation,providing fast and precise cell quantitation.Further,optically cleared organs enabled three-dimensional morphometry at an unprecedented scale including dermatome-wide innervation studies,tracing of intramuscular nerve branches or mapping of neurovascular networks.Given their wide-ranging applicability,rapid processing times,and low costs,tissue clearing techniques are likely to be a key technology for next-generation nerve repair studies.All procedures were approved by the Hospital for Sick Children’s Laboratory Animal Services Committee(49871/9)on November 9,2019.展开更多
Anthropometry can analyze the size,weight,and proportion of the human body objectively and quantitatively to supplement the visual assessment.Various non-invasive three-dimensional(3D)anthropometric techniques have be...Anthropometry can analyze the size,weight,and proportion of the human body objectively and quantitatively to supplement the visual assessment.Various non-invasive three-dimensional(3D)anthropometric techniques have been applied to assess soft tissues’3D morphology in the clinical practice.Among them,non-invasive stereophotogrammetry and laser scanning techniques are becoming increasingly popular in craniofacial surgery and plastic surgery.They have been applied for craniofacial growth estimation and morphometric investigation,genetic and acquired malformation diagnosis,as well as orthodontic or surgical treatment arrangement and outcome evaluation.However,few studies have been published for assessing the 3D morphology of soft tissues in the periorbital region.This paper reviews the studies involving the application and evaluation of the increasingly popular 3D photogrammetry in the periorbital region.These studies proposed detailed and standardized protocols for three-dimensionally assessing linear,curvilinear,angular,as well as volumetric measurements,and verified its high reliability in the periorbital region(even higher than caliper-derived direct measurements).In the future,reliable and accurate 3D imaging techniques,as well as standardized analyzing protocols,may find applications in following up morphological growth,preoperatively diagnosing and assessing patient periorbital conditions,planning surgical procedures,postoperatively evaluating treatment outcomes of a specific procedure,and comparing the differences in surgical results between various procedures,studies,as well as populations.展开更多
In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images ...In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS), three-dimensional models of upper airway cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed threedimensional models precisely preserve the original configuration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosingdiseases related to anatomical structure and function of the upper airway.展开更多
A new kind of tunnel support was put forward on the basis of the anchor spraysupport principle. The mechanics of the new three-dimensional steel bar shotcrete liningsupport was studied and the structure's internal...A new kind of tunnel support was put forward on the basis of the anchor spraysupport principle. The mechanics of the new three-dimensional steel bar shotcrete liningsupport was studied and the structure's internal forces were analyzed. The model experiment was done relying on the industrial test. The conclusion of numerical calculationsproved that the ANSYS program is reasonable and creditable. It was compared to otherkinds of support that are commonly used in soft rock tunnels. The technique and economiccontrasts of the typical tunnel with support three-dimensional steel bar were completed.展开更多
The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuato...The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.展开更多
The recently developed hard-magnetic soft(HMS)materials manufactured by embedding high-coercivity micro-particles into soft matrices have received considerable attention from researchers in diverse fields,e.g.,soft ro...The recently developed hard-magnetic soft(HMS)materials manufactured by embedding high-coercivity micro-particles into soft matrices have received considerable attention from researchers in diverse fields,e.g.,soft robotics,flexible electronics,and biomedicine.Theoretical investigations on large deformations of HMS structures are significant foundations of their applications.This work is devoted to developing a powerful theoretical tool for modeling and computing the complicated nonplanar deformations of flexible beams.A so-called quaternion beam model is proposed to break the singularity limitation of the existing geometrically exact(GE)beam model.The singularity-free governing equations for the three-dimensional(3D)large deformations of an HMS beam are first derived,and then solved with the Galerkin discretization method and the trustregion-dogleg iterative algorithm.The correctness of this new model and the utilized algorithms is verified by comparing the present results with the previous ones.The superiority of a quaternion beam model in calculating the complicated large deformations of a flexible beam is shown through several benchmark examples.It is found that the purpose of the HMS beam deformation is to eliminate the direction deviation between the residual magnetization and the applied magnetic field.The proposed new model and the revealed mechanism are supposed to be useful for guiding the engineering applications of flexible structures.展开更多
A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport...A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.展开更多
In vitro culture of spermatogonial stem cells (SSCs) has generally been performed using two-dimensional (2D) culture systems; however, such cultures have not led to the development of complete spermatogenesis. It ...In vitro culture of spermatogonial stem cells (SSCs) has generally been performed using two-dimensional (2D) culture systems; however, such cultures have not led to the development of complete spermatogenesis. It seems that 2D systems do not replicate optimal conditions of the seminiferous tubules (including those generated by the SSC niche) and necessary for spermatogenesis. Recently, one of our laboratories has been able to induce proliferation and differentiation of mouse testicular germ cells to meiotic and postmeiotic stages including generation of sperm in a 3D soft agar culture system (SACS) and a 3D methylcellulose culture system (MCS). It was suggested that SACS and MCS form a special 3D microenvironment that mimics germ cell niche formation in the seminiferous tubules, and thus permits mouse spermatogenesis in vitro. In this review, we (1) provide a brief overview of the differences in spermatogenesis in rodents and primates, (2) summarize data related to attempts to generate sperm in vitro, (3) report for the first time formation of colonies/clusters of cells and differentiation of meiotic (expression of CREM-1) and postmeiotic (expression of acrosin) germ cells from undifferentiated spermatogonia isolated from the testis of prepubertal rhesus monkeys and cultured in SACS and MCS, and (4) indicate research needed to optimize 3D systems for in vitro primate spermatogenesis and for possible future application to man.展开更多
We present a kirigami-inspired design scheme for a robotic hand by 3D printable folds and cuts.The unique contribution is the printable flexible hand,which provides flexibility and maneuverability that is unavailable ...We present a kirigami-inspired design scheme for a robotic hand by 3D printable folds and cuts.The unique contribution is the printable flexible hand,which provides flexibility and maneuverability that is unavailable in rigid robotic systems.The integration of sensors in the robotic system enables force adjustment for robotic systems applicable in the future.The experimental results have shown that this design can perform everyday tasks through grasping and pinching different items.The fingers can bend from 40 to 100 degrees.Furthermore,the direct printable kirigami cuts and folds from soft elastic printable materials have significant potential for prosthetic devices.The printable kirigami design framework opens the possibility for future developments and modifications in numerous robotic applications.展开更多
Magnetic materials are of increasing importance for many essential applications due to their unique magnetic properties.However,due to the limited fabrication ability,magnetic materials are restricted by simple geomet...Magnetic materials are of increasing importance for many essential applications due to their unique magnetic properties.However,due to the limited fabrication ability,magnetic materials are restricted by simple geometric shapes.Three-dimensional(3D)printing is a highly versatile technique that can be utilized for constructing magnetic materials.The shape flexibility of magnets unleashes opportunities for magnetic composites with reducing post-manufacturing costs,motivating the review on 3D printing of magnetic materials.This paper focuses on recent achievements of magnetic materials using 3D printing technologies,followed by the characterization of their magnetic properties,which are further enhanced by modification.Interestingly,the corresponding properties depend on the intrinsic nature of starting materials,3D printing processing parameters,and the optimized structural design.More emphasis is placed on the functional applications of 3D-printed magnetic materials in different fields.Lastly,the current challenges and future opportunities are also addressed.展开更多
基金the German Research Foundation(DA 2255/1-1,to SCD).
文摘Morphological analyses are key outcome assessments for nerve regeneration studies but are historically limited to tissue sections.Novel optical tissue clearing techniques enabling three-dimensional imaging of entire organs at a subcellular resolution have revolutionized morphological studies of the brain.To extend their applicability to experimental nerve repair studies we adapted these techniques to nerves and their motor and sensory targets in rats.The solvent-based protocols rendered harvested peripheral nerves and their target organs transparent within 24 hours while preserving tissue architecture and fluorescence.The optical clearing was compatible with conventional laboratory techniques,including retrograde labeling studies,and computational image segmentation,providing fast and precise cell quantitation.Further,optically cleared organs enabled three-dimensional morphometry at an unprecedented scale including dermatome-wide innervation studies,tracing of intramuscular nerve branches or mapping of neurovascular networks.Given their wide-ranging applicability,rapid processing times,and low costs,tissue clearing techniques are likely to be a key technology for next-generation nerve repair studies.All procedures were approved by the Hospital for Sick Children’s Laboratory Animal Services Committee(49871/9)on November 9,2019.
基金This study was supported by the Koeln Fortune Program/Faculty of Medicine,University of Cologne,Germany(No.2680148101)the State Scholarship Fund from China Scholarship Council,China(No.201708080141).
文摘Anthropometry can analyze the size,weight,and proportion of the human body objectively and quantitatively to supplement the visual assessment.Various non-invasive three-dimensional(3D)anthropometric techniques have been applied to assess soft tissues’3D morphology in the clinical practice.Among them,non-invasive stereophotogrammetry and laser scanning techniques are becoming increasingly popular in craniofacial surgery and plastic surgery.They have been applied for craniofacial growth estimation and morphometric investigation,genetic and acquired malformation diagnosis,as well as orthodontic or surgical treatment arrangement and outcome evaluation.However,few studies have been published for assessing the 3D morphology of soft tissues in the periorbital region.This paper reviews the studies involving the application and evaluation of the increasingly popular 3D photogrammetry in the periorbital region.These studies proposed detailed and standardized protocols for three-dimensionally assessing linear,curvilinear,angular,as well as volumetric measurements,and verified its high reliability in the periorbital region(even higher than caliper-derived direct measurements).In the future,reliable and accurate 3D imaging techniques,as well as standardized analyzing protocols,may find applications in following up morphological growth,preoperatively diagnosing and assessing patient periorbital conditions,planning surgical procedures,postoperatively evaluating treatment outcomes of a specific procedure,and comparing the differences in surgical results between various procedures,studies,as well as populations.
基金The project supported by the National Natural Science Foundation of China(10672036,10472025 and 10421002)the Natural Science Foundation of Liaoning Province(20032109)
文摘In this paper, the authors present airflow field characteristics of human upper airway and soft palate movement attitude during breathing. On the basis of the data taken from the spiral computerized tomography images of a healthy person and a patient with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS), three-dimensional models of upper airway cavity and soft palate are reconstructed by the method of surface rendering. Numerical simulation is performed for airflow in the upper airway and displacement of soft palate by fluid-structure interaction analysis. The reconstructed threedimensional models precisely preserve the original configuration of upper airways and soft palate. The results of the pressure and velocity distributions in the airflow field are quantitatively determined, and the displacement of soft palate is presented. Pressure gradients of airway are lower for the healthy person and the airflow distribution is quite uniform in the case of free breathing. However, the OSAHS patient remarkably escalates both the pressure and velocity in the upper airway, and causes higher displacement of the soft palate. The present study is useful in revealing pathogenesis and quantitative mutual relationship between configuration and function of the upper airway as well as in diagnosingdiseases related to anatomical structure and function of the upper airway.
文摘A new kind of tunnel support was put forward on the basis of the anchor spraysupport principle. The mechanics of the new three-dimensional steel bar shotcrete liningsupport was studied and the structure's internal forces were analyzed. The model experiment was done relying on the industrial test. The conclusion of numerical calculationsproved that the ANSYS program is reasonable and creditable. It was compared to otherkinds of support that are commonly used in soft rock tunnels. The technique and economiccontrasts of the typical tunnel with support three-dimensional steel bar were completed.
基金the National Natural Science Foundation of China(Nos.11572002 and 12002032)the China Postdoctoral Science Foundation(Nos.BX20200056 and 2020M670149)。
文摘The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile objects.As one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input source.In this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different functionalities.To enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing speed.By carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting motions.In addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.
基金Project supported by the National Key Research and Development Program of China(No.2018YFA0703200)the National Natural Science Foundation of China(Nos.52205594 and51820105008)+1 种基金the China National Postdoctoral Program for Innovative Talents(No.BX20220118)the China Postdoctoral Science Foundation(No.2021M701306)。
文摘The recently developed hard-magnetic soft(HMS)materials manufactured by embedding high-coercivity micro-particles into soft matrices have received considerable attention from researchers in diverse fields,e.g.,soft robotics,flexible electronics,and biomedicine.Theoretical investigations on large deformations of HMS structures are significant foundations of their applications.This work is devoted to developing a powerful theoretical tool for modeling and computing the complicated nonplanar deformations of flexible beams.A so-called quaternion beam model is proposed to break the singularity limitation of the existing geometrically exact(GE)beam model.The singularity-free governing equations for the three-dimensional(3D)large deformations of an HMS beam are first derived,and then solved with the Galerkin discretization method and the trustregion-dogleg iterative algorithm.The correctness of this new model and the utilized algorithms is verified by comparing the present results with the previous ones.The superiority of a quaternion beam model in calculating the complicated large deformations of a flexible beam is shown through several benchmark examples.It is found that the purpose of the HMS beam deformation is to eliminate the direction deviation between the residual magnetization and the applied magnetic field.The proposed new model and the revealed mechanism are supposed to be useful for guiding the engineering applications of flexible structures.
基金funded by the National Natural Science Foundation of China(No.21776051)the Natural Science Foundations of Guangdong(No.2018A030313423)。
文摘A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.
文摘In vitro culture of spermatogonial stem cells (SSCs) has generally been performed using two-dimensional (2D) culture systems; however, such cultures have not led to the development of complete spermatogenesis. It seems that 2D systems do not replicate optimal conditions of the seminiferous tubules (including those generated by the SSC niche) and necessary for spermatogenesis. Recently, one of our laboratories has been able to induce proliferation and differentiation of mouse testicular germ cells to meiotic and postmeiotic stages including generation of sperm in a 3D soft agar culture system (SACS) and a 3D methylcellulose culture system (MCS). It was suggested that SACS and MCS form a special 3D microenvironment that mimics germ cell niche formation in the seminiferous tubules, and thus permits mouse spermatogenesis in vitro. In this review, we (1) provide a brief overview of the differences in spermatogenesis in rodents and primates, (2) summarize data related to attempts to generate sperm in vitro, (3) report for the first time formation of colonies/clusters of cells and differentiation of meiotic (expression of CREM-1) and postmeiotic (expression of acrosin) germ cells from undifferentiated spermatogonia isolated from the testis of prepubertal rhesus monkeys and cultured in SACS and MCS, and (4) indicate research needed to optimize 3D systems for in vitro primate spermatogenesis and for possible future application to man.
基金This work was supported by Singapore Academic Research Fund under Grant R397000353114.
文摘We present a kirigami-inspired design scheme for a robotic hand by 3D printable folds and cuts.The unique contribution is the printable flexible hand,which provides flexibility and maneuverability that is unavailable in rigid robotic systems.The integration of sensors in the robotic system enables force adjustment for robotic systems applicable in the future.The experimental results have shown that this design can perform everyday tasks through grasping and pinching different items.The fingers can bend from 40 to 100 degrees.Furthermore,the direct printable kirigami cuts and folds from soft elastic printable materials have significant potential for prosthetic devices.The printable kirigami design framework opens the possibility for future developments and modifications in numerous robotic applications.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2020QE040)the financial support by the Young Taishan Scholars Program of Shandong Province(No.201909099)。
文摘Magnetic materials are of increasing importance for many essential applications due to their unique magnetic properties.However,due to the limited fabrication ability,magnetic materials are restricted by simple geometric shapes.Three-dimensional(3D)printing is a highly versatile technique that can be utilized for constructing magnetic materials.The shape flexibility of magnets unleashes opportunities for magnetic composites with reducing post-manufacturing costs,motivating the review on 3D printing of magnetic materials.This paper focuses on recent achievements of magnetic materials using 3D printing technologies,followed by the characterization of their magnetic properties,which are further enhanced by modification.Interestingly,the corresponding properties depend on the intrinsic nature of starting materials,3D printing processing parameters,and the optimized structural design.More emphasis is placed on the functional applications of 3D-printed magnetic materials in different fields.Lastly,the current challenges and future opportunities are also addressed.