Biofouling has been a persistent problem in marine riser system, resulting in energy waste and equipment damage. Inthis study, a kind of water wave-driven contact-mode flexible triboelectric nanogeneration has been pr...Biofouling has been a persistent problem in marine riser system, resulting in energy waste and equipment damage. Inthis study, a kind of water wave-driven contact-mode flexible triboelectric nanogeneration has been prepared byusing graphene-doped PDMS as dielectric friction material. When the graphene content is 2%, the average outputvoltage can reach 46 V under the contact frequency 10 Hz. The flexible triboelectric nanogeneration encapsulationmodule is impinged by water waves to generate alternating microelectric field on the riser surface and destroy theadhesion conditions of microorganisms during the biofilm stage. In the biofouling experiments at different stages, thebiofouling area of the platymonas subcordiformis has been reduced by 53%, 62% and 61%. It provides a new ideafor effective treatment of biofouling of mussels, oysters and barnacles attached to risers.展开更多
Direct Ink Writing(DIW)has demonstrated great potential as a versatile method to 3D print multifunctional structures.In this work,we report the implementation of hydrogel meta-structures using DIW at room temperature,...Direct Ink Writing(DIW)has demonstrated great potential as a versatile method to 3D print multifunctional structures.In this work,we report the implementation of hydrogel meta-structures using DIW at room temperature,which seamlessly integrate large specific surface areas,interconnected porous characteristics,mechanical toughness,biocompatibility,and water absorption and retention capabilities.Robust but hydrophobic polymers and weakly crosslinked nature-origin hydrogels form a balance in the self-supporting ink,allowing us to directly print complex meta-structures without sacrificial materials and heating extrusion.Mechanically,the mixed bending or stretching of symmetrical re-entrant cellular lattices and the unique curvature patterns are combined to provide little lateral expansion and large compressive energy absorbance when external forces are applied on the printed meta-structures.In addition,we have successfully demonstrated ear,aortic valve conduits and hierarchical architectures.We anticipate that the reported 3D meta-structured hydrogel would offer a new strategy to develop functional biomaterials for tissue engineering applications in the future.展开更多
As the essential technology of human-robotics interactive wearable devices,the robotic knee prosthesis can provide above-knee amputations with functional knee compensations to realize their physical and psychological ...As the essential technology of human-robotics interactive wearable devices,the robotic knee prosthesis can provide above-knee amputations with functional knee compensations to realize their physical and psychological social regression.With the development of mechanical and mechatronic science and technology,the fully active knee prosthesis that can provide subjects with actuating torques has demonstrated a better wearing performance in slope walking and stair ascent when compared with the passive and the semi-active ones.Additionally,with intelligent human-robotics control strategies and algorithms,the wearing effect of the knee prosthesis has been greatly enhanced in terms of stance stability and swing mobility.Therefore,to help readers to obtain an overview of recent progress in robotic knee prosthesis,this paper systematically categorized knee prostheses according to their integrated functions and introduced related research in the past ten years(2010−2020)regarding(1)mechanical design,including uniaxial,four-bar,and multi-bar knee structures,(2)actuating technology,including rigid and elastic actuation,and(3)control method,including mode identification,motion prediction,and automatic control.Quantitative and qualitative analysis and comparison of robotic knee prosthesis-related techniques are conducted.The development trends are concluded as follows:(1)bionic and lightweight structures with better mechanical performance,(2)bionic elastic actuation with energy-saving effect,(3)artificial intelligence-based bionic prosthetic control.Besides,challenges and innovative insights of customized lightweight bionic knee joint structure,highly efficient compact bionic actuation,and personalized daily multi-mode gait adaptation are also discussed in-depth to facilitate the future development of the robotic knee prosthesis.展开更多
Formation of graded biomaterials to render shape-morphing scaffolds for 4D biofabrication holds great promise in fabrication of complex structures and the recapitulation of critical dynamics for tissue/organ regenerat...Formation of graded biomaterials to render shape-morphing scaffolds for 4D biofabrication holds great promise in fabrication of complex structures and the recapitulation of critical dynamics for tissue/organ regeneration.Here we describe a facile generation of an adjustable and robust gradient using a single-or multi-material one-step fabrication strategy for 4D biofabrication.By simply photocrosslinking a mixed solution of a photocrosslinkable polymer macromer,photoinitiator(PI),UV absorber and live cells,a cell-laden gradient hydrogel with pre-programmable deformation can be generated.Gradient formation was demonstrated in various polymers including poly(ethylene glycol)(PEG),alginate,and gelatin derivatives using various UV absorbers that present overlap in UV spectrum with that of the PI UV absorbance spectrum.Moreover,this simple and effective method was used as a universal platform to integrate with other hydrogel-engineering techniques such as photomask-aided microfabrication,photo-patterning,ion-transfer printing,and 3D bioprinting to fabricate more advanced cell-laden scaffold structures.Lastly,proof-of-concept 4D tissue engineering was demonstrated in a study of 4D bone-like tissue formation.The strategy’s simplicity along with its versatility paves a new way in solving the hurdle of achieving temporal shape changes in cell-laden single-component hydrogel scaffolds and may expedite the development of 4D biofabricated constructs for biological applications.展开更多
We present the first fabrication of sub-10 nm nanopores in freestanding polymer membranes via a simple,costeffective,high-throughput but deterministic fabrication method.Nanopores in the range of 10 nm were initially ...We present the first fabrication of sub-10 nm nanopores in freestanding polymer membranes via a simple,costeffective,high-throughput but deterministic fabrication method.Nanopores in the range of 10 nm were initially produced via a single-step nanoimprinting process,which was further reduced to sub-10 nm pores via a post-NIL polymer reflow process.The low shrinkage rate of 2.7 nm/min obtained under the conditions used for the reflow process was the key to achieving sub-10 nm pores with a controllable pore size.The fabricated SU-8 nanopore membranes were successfully employed for transient current measurements during the translocation of DNA molecules through the nanopores.展开更多
In this study,energetic,economic,and environmental analysis of solid oxide fuel cell-based combined cooling,heating,and power(SOFC-CCHP)system is proposed for a cancer care hospital building.The energy required for th...In this study,energetic,economic,and environmental analysis of solid oxide fuel cell-based combined cooling,heating,and power(SOFC-CCHP)system is proposed for a cancer care hospital building.The energy required for the hospital power,cooling,and heating demands was obtained based on real and detailed field data,which could serve as a reference for future works in the field.These data with a 3D model for the hospital building are constructed and created in eQUEST software to precisely calculate the energy demands of the existing system(baseline case).Then,energetic,economic,and environmental models were developed to compare and assess the performance of the proposed SOFC-CCHP system.The results show that the proposed system can cover about 49% to 77% of the power demand of the hospital with an overall efficiency of 78.3%.Also,the results show that the levelized cost of electricity of the system and its payback period at the designed capacity of the SOFC is 0.087S/kWh and 10 years,respectively.Furthermore,compared to the baseline system of the hospital,the SOFC-CCHP reduces the CO_(2) emission by 89% over the year.The sensitivity analysis showed that a maximum SOFC efficiency of 52%and overall efficiency of 80%are achieved at cell operating temperature of 1027℃ and fuel utilization factor of 0.85.展开更多
Micro/nano-porous polymeric material is considered a unique industrial material due to its extremelylow thermal conductivity, low density, and high surface area. Therefore, it is necessary to establishan accurate ther...Micro/nano-porous polymeric material is considered a unique industrial material due to its extremelylow thermal conductivity, low density, and high surface area. Therefore, it is necessary to establishan accurate thermal conductivity prediction model suiting their applicable conditions and provide atheoretical basis for expanding their applications. In this work, the development of the calculationmodel of equivalent thermal conductivity of micro/nano-porous polymeric materials in recent yearsis summarized. Firstly, it reviews the process of establishing the overall equivalent thermal conductivity calculation model for micro/nanoporous polymers. Then, the predicted calculation models ofthermal conductivity are introduced separately according to the conductive and radiative thermalconductivity models. In addition, the thermal conduction part is divided into the gaseous thermalconductivity model, solid thermal conductivity model and gas-solid coupling model. Finally, it isconcluded that, compared with other porous materials, there are few studies on heat transfer of micro/nanoporous polymers, especially on the particular heat transfer mechanisms such as scale effectsat the micro/nanoscale. In particular, the following aspects of porous polymers still need to be furtherstudied: micro scaled thermal radiation, heat transfer characteristics of particular morphologies at thenanoscales, heat transfer mechanism and impact factors of micro/nanoporous polymers. Such studieswould provide a more accurate prediction of thermal conductivity and a broader application in energyconversion and storage systems.展开更多
Caenorhabditis elegans(C.elegans)has been a popular model organism for several decades since its first discovery of the huge research potential for modeling human diseases and genetics.Sorting is an important means of...Caenorhabditis elegans(C.elegans)has been a popular model organism for several decades since its first discovery of the huge research potential for modeling human diseases and genetics.Sorting is an important means of providing stage-or age-synchronized worm populations for many worm-based bioassays.However,conventional manual techniques for C.elegans sorting are tedious and inefficient,and commercial complex object parametric analyzer and sorter is too expensive and bulky for most laboratories.Recently,the development of lab-on-a-chip(microfluidics)technology has greatly facilitated C.elegans studies where large numbers of synchronized worm populations are required and advances of new designs,mechanisms,and automation algorithms.Most previous reviews have focused on the development of microfluidic devices but lacked the summaries and discussion of the biological research demands of C.elegans,and are hard to read for worm researchers.We aim to comprehensively review the up-to-date microfluidic-assisted C.elegans sorting developments from several angles to suit different background researchers,i.e.,biologists and engineers.First,we highlighted the microfluidic C.elegans sorting devices'advantages and limitations compared to the conventional commercialized worm sorting tools.Second,to benefit the engineers,we reviewed the current devices from the perspectives of active or passive sorting,sorting strategies,target populations,and sorting criteria.Third,to benefit the biologists,we reviewed the contributions of sorting to biological research.We expect,by providing this comprehensive review,that each researcher from this multidisciplinary community can effectively find the needed information and,in turn,facilitate future research.展开更多
Chip-to-chip and world-to-chip fluidic interconnections are paramount to enable the passage of liquids between component chips and to/from microfluidic systems.Unfortunately,most interconnect designs add additional ph...Chip-to-chip and world-to-chip fluidic interconnections are paramount to enable the passage of liquids between component chips and to/from microfluidic systems.Unfortunately,most interconnect designs add additional physical constraints to chips with each additional interconnect leading to over-constrained microfluidic systems.The competing constraints provided by multiple interconnects induce strain in the chips,creating indeterminate dead volumes and misalignment between chips that comprise the microfluidic system.A novel,gasketless superhydrophobic fluidic interconnect(GSFI)that uses capillary forces to form a liquid bridge suspended between concentric through-holes and acting as a fluid passage was investigated.The GSFI decouples the alignment between component chips from the interconnect function and the attachment of the meniscus of the liquid bridge to the edges of the holes produces negligible dead volume.This passive seal was created by patterning parallel superhydrophobic surfaces(water contact angle>150°)around concentric microfluidic ports separated by a gap.The relative position of the two polymer chips was determined by passive kinematic constraints,three spherical ball bearings seated in v-grooves.A leakage pressure model derived from the Young-Laplace equation was used to estimate the leakage pressure at failure for the liquid bridge.Injection-molded,Cyclic Olefin Copolymer(COC)chip assemblies with assembly gaps from 3 to 240μm were used to experimentally validate the model.The maximum leakage pressure measured for the GSFI was 21.4 kPa(3.1 psig),which corresponded to a measured mean assembly gap of 3μm,and decreased to 0.5 kPa(0.073 psig)at a mean assembly gap of 240μm.The effect of radial misalignment on the efficacy of the gasketless seals was tested and no significant effect was observed.This may be a function of how the liquid bridges are formed during the priming of the chip,but additional research is required to test that hypothesis.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3401400)。
文摘Biofouling has been a persistent problem in marine riser system, resulting in energy waste and equipment damage. Inthis study, a kind of water wave-driven contact-mode flexible triboelectric nanogeneration has been prepared byusing graphene-doped PDMS as dielectric friction material. When the graphene content is 2%, the average outputvoltage can reach 46 V under the contact frequency 10 Hz. The flexible triboelectric nanogeneration encapsulationmodule is impinged by water waves to generate alternating microelectric field on the riser surface and destroy theadhesion conditions of microorganisms during the biofilm stage. In the biofouling experiments at different stages, thebiofouling area of the platymonas subcordiformis has been reduced by 53%, 62% and 61%. It provides a new ideafor effective treatment of biofouling of mussels, oysters and barnacles attached to risers.
基金the financial support of the National Science Foundation(ECCS-1916839 and CBET-1931777)the support of the National Institute of Health under grant number R21 HD090680-01support by the U.S.Army Research Office through the Institute for Soldier Nanotechnologies at MIT,under Contract Number W911NF-13-D-0001.
文摘Direct Ink Writing(DIW)has demonstrated great potential as a versatile method to 3D print multifunctional structures.In this work,we report the implementation of hydrogel meta-structures using DIW at room temperature,which seamlessly integrate large specific surface areas,interconnected porous characteristics,mechanical toughness,biocompatibility,and water absorption and retention capabilities.Robust but hydrophobic polymers and weakly crosslinked nature-origin hydrogels form a balance in the self-supporting ink,allowing us to directly print complex meta-structures without sacrificial materials and heating extrusion.Mechanically,the mixed bending or stretching of symmetrical re-entrant cellular lattices and the unique curvature patterns are combined to provide little lateral expansion and large compressive energy absorbance when external forces are applied on the printed meta-structures.In addition,we have successfully demonstrated ear,aortic valve conduits and hierarchical architectures.We anticipate that the reported 3D meta-structured hydrogel would offer a new strategy to develop functional biomaterials for tissue engineering applications in the future.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.62003060,51975070 and 62033001)the National Key Research and Development Program of China under Grant 2020YFB1313000.
文摘As the essential technology of human-robotics interactive wearable devices,the robotic knee prosthesis can provide above-knee amputations with functional knee compensations to realize their physical and psychological social regression.With the development of mechanical and mechatronic science and technology,the fully active knee prosthesis that can provide subjects with actuating torques has demonstrated a better wearing performance in slope walking and stair ascent when compared with the passive and the semi-active ones.Additionally,with intelligent human-robotics control strategies and algorithms,the wearing effect of the knee prosthesis has been greatly enhanced in terms of stance stability and swing mobility.Therefore,to help readers to obtain an overview of recent progress in robotic knee prosthesis,this paper systematically categorized knee prostheses according to their integrated functions and introduced related research in the past ten years(2010−2020)regarding(1)mechanical design,including uniaxial,four-bar,and multi-bar knee structures,(2)actuating technology,including rigid and elastic actuation,and(3)control method,including mode identification,motion prediction,and automatic control.Quantitative and qualitative analysis and comparison of robotic knee prosthesis-related techniques are conducted.The development trends are concluded as follows:(1)bionic and lightweight structures with better mechanical performance,(2)bionic elastic actuation with energy-saving effect,(3)artificial intelligence-based bionic prosthetic control.Besides,challenges and innovative insights of customized lightweight bionic knee joint structure,highly efficient compact bionic actuation,and personalized daily multi-mode gait adaptation are also discussed in-depth to facilitate the future development of the robotic knee prosthesis.
基金The authors gratefully acknowledge funding from the National Institutes of Health’s National Institute of Arthritis and Musculoskeletal and Skin Diseases(R01AR069564,and R01AR066193E.A.)+4 种基金National Institute of Biomedical Imaging and Bioengineering(R01EB023907E.A.)and National Heart,Lung,and Blood Institute(T32HL007829R.T.)The contents of this publication are solely the responsibility of the authors and do not necessarily represent the official views of the National Institutes of Health.The authors also thank Susan R.Ross at University of Illinois at Chicago for generously providing the NIH3T3 cells.
文摘Formation of graded biomaterials to render shape-morphing scaffolds for 4D biofabrication holds great promise in fabrication of complex structures and the recapitulation of critical dynamics for tissue/organ regeneration.Here we describe a facile generation of an adjustable and robust gradient using a single-or multi-material one-step fabrication strategy for 4D biofabrication.By simply photocrosslinking a mixed solution of a photocrosslinkable polymer macromer,photoinitiator(PI),UV absorber and live cells,a cell-laden gradient hydrogel with pre-programmable deformation can be generated.Gradient formation was demonstrated in various polymers including poly(ethylene glycol)(PEG),alginate,and gelatin derivatives using various UV absorbers that present overlap in UV spectrum with that of the PI UV absorbance spectrum.Moreover,this simple and effective method was used as a universal platform to integrate with other hydrogel-engineering techniques such as photomask-aided microfabrication,photo-patterning,ion-transfer printing,and 3D bioprinting to fabricate more advanced cell-laden scaffold structures.Lastly,proof-of-concept 4D tissue engineering was demonstrated in a study of 4D bone-like tissue formation.The strategy’s simplicity along with its versatility paves a new way in solving the hurdle of achieving temporal shape changes in cell-laden single-component hydrogel scaffolds and may expedite the development of 4D biofabricated constructs for biological applications.
基金This research was supported by the P41 Center for BioModular Multiscale Systems for Precision Medicine(P41EB020594)from the National Institutes of Health。
文摘We present the first fabrication of sub-10 nm nanopores in freestanding polymer membranes via a simple,costeffective,high-throughput but deterministic fabrication method.Nanopores in the range of 10 nm were initially produced via a single-step nanoimprinting process,which was further reduced to sub-10 nm pores via a post-NIL polymer reflow process.The low shrinkage rate of 2.7 nm/min obtained under the conditions used for the reflow process was the key to achieving sub-10 nm pores with a controllable pore size.The fabricated SU-8 nanopore membranes were successfully employed for transient current measurements during the translocation of DNA molecules through the nanopores.
基金The work presented in this publication was made possible by NPRP-S grant#[11S-1231-170155]from the Qatar National Research Fund(a member of Qatar Foundation)。
文摘In this study,energetic,economic,and environmental analysis of solid oxide fuel cell-based combined cooling,heating,and power(SOFC-CCHP)system is proposed for a cancer care hospital building.The energy required for the hospital power,cooling,and heating demands was obtained based on real and detailed field data,which could serve as a reference for future works in the field.These data with a 3D model for the hospital building are constructed and created in eQUEST software to precisely calculate the energy demands of the existing system(baseline case).Then,energetic,economic,and environmental models were developed to compare and assess the performance of the proposed SOFC-CCHP system.The results show that the proposed system can cover about 49% to 77% of the power demand of the hospital with an overall efficiency of 78.3%.Also,the results show that the levelized cost of electricity of the system and its payback period at the designed capacity of the SOFC is 0.087S/kWh and 10 years,respectively.Furthermore,compared to the baseline system of the hospital,the SOFC-CCHP reduces the CO_(2) emission by 89% over the year.The sensitivity analysis showed that a maximum SOFC efficiency of 52%and overall efficiency of 80%are achieved at cell operating temperature of 1027℃ and fuel utilization factor of 0.85.
基金the National Natural Science Foundation of China(Nos.51776050 and 51536001).
文摘Micro/nano-porous polymeric material is considered a unique industrial material due to its extremelylow thermal conductivity, low density, and high surface area. Therefore, it is necessary to establishan accurate thermal conductivity prediction model suiting their applicable conditions and provide atheoretical basis for expanding their applications. In this work, the development of the calculationmodel of equivalent thermal conductivity of micro/nano-porous polymeric materials in recent yearsis summarized. Firstly, it reviews the process of establishing the overall equivalent thermal conductivity calculation model for micro/nanoporous polymers. Then, the predicted calculation models ofthermal conductivity are introduced separately according to the conductive and radiative thermalconductivity models. In addition, the thermal conduction part is divided into the gaseous thermalconductivity model, solid thermal conductivity model and gas-solid coupling model. Finally, it isconcluded that, compared with other porous materials, there are few studies on heat transfer of micro/nanoporous polymers, especially on the particular heat transfer mechanisms such as scale effectsat the micro/nanoscale. In particular, the following aspects of porous polymers still need to be furtherstudied: micro scaled thermal radiation, heat transfer characteristics of particular morphologies at thenanoscales, heat transfer mechanism and impact factors of micro/nanoporous polymers. Such studieswould provide a more accurate prediction of thermal conductivity and a broader application in energyconversion and storage systems.
基金support from the programs of the Natural Science Foundation of the Jiangsu Higher Education(20KJB460024 and 22KJB460033)Jiangsu Science and Technology Programme-Young Scholar(BK20200251)+4 种基金Jiangsu Province High-level Innovation and Entrepreneurship Talent Plan(2020-30803)XJTLU Key Programme Special Fund-Exploratory Research Programme(KSF-E-39)XJTLU Research Development Fund(RDF-18-02-20)support from Xi'an Jiaotong-Liverpool University to W.Y.(PGRS1906040)and S.D.(PGRS1912019)supported by the XJTLU AI University Research Centre and Jiangsu Province Engineering Research Centre of Data Science and Cognitive Computation at XJTLU.
文摘Caenorhabditis elegans(C.elegans)has been a popular model organism for several decades since its first discovery of the huge research potential for modeling human diseases and genetics.Sorting is an important means of providing stage-or age-synchronized worm populations for many worm-based bioassays.However,conventional manual techniques for C.elegans sorting are tedious and inefficient,and commercial complex object parametric analyzer and sorter is too expensive and bulky for most laboratories.Recently,the development of lab-on-a-chip(microfluidics)technology has greatly facilitated C.elegans studies where large numbers of synchronized worm populations are required and advances of new designs,mechanisms,and automation algorithms.Most previous reviews have focused on the development of microfluidic devices but lacked the summaries and discussion of the biological research demands of C.elegans,and are hard to read for worm researchers.We aim to comprehensively review the up-to-date microfluidic-assisted C.elegans sorting developments from several angles to suit different background researchers,i.e.,biologists and engineers.First,we highlighted the microfluidic C.elegans sorting devices'advantages and limitations compared to the conventional commercialized worm sorting tools.Second,to benefit the engineers,we reviewed the current devices from the perspectives of active or passive sorting,sorting strategies,target populations,and sorting criteria.Third,to benefit the biologists,we reviewed the contributions of sorting to biological research.We expect,by providing this comprehensive review,that each researcher from this multidisciplinary community can effectively find the needed information and,in turn,facilitate future research.
基金the LSU Department of Mechanical&Industrial Engineering,the Roy O.Martin Jr.Lumber Co.Professorship of Mechanical Engineering,the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health through a research grant R01-EB-010087a Biotechnology Resource Center Grant P41-EB-020594+1 种基金d the State of Louisiana Board of Regents Enhancement Program(LEQSF(2006-07)-ENH-TR-20)the Louisiana Governor's Biotechnology Initiative.
文摘Chip-to-chip and world-to-chip fluidic interconnections are paramount to enable the passage of liquids between component chips and to/from microfluidic systems.Unfortunately,most interconnect designs add additional physical constraints to chips with each additional interconnect leading to over-constrained microfluidic systems.The competing constraints provided by multiple interconnects induce strain in the chips,creating indeterminate dead volumes and misalignment between chips that comprise the microfluidic system.A novel,gasketless superhydrophobic fluidic interconnect(GSFI)that uses capillary forces to form a liquid bridge suspended between concentric through-holes and acting as a fluid passage was investigated.The GSFI decouples the alignment between component chips from the interconnect function and the attachment of the meniscus of the liquid bridge to the edges of the holes produces negligible dead volume.This passive seal was created by patterning parallel superhydrophobic surfaces(water contact angle>150°)around concentric microfluidic ports separated by a gap.The relative position of the two polymer chips was determined by passive kinematic constraints,three spherical ball bearings seated in v-grooves.A leakage pressure model derived from the Young-Laplace equation was used to estimate the leakage pressure at failure for the liquid bridge.Injection-molded,Cyclic Olefin Copolymer(COC)chip assemblies with assembly gaps from 3 to 240μm were used to experimentally validate the model.The maximum leakage pressure measured for the GSFI was 21.4 kPa(3.1 psig),which corresponded to a measured mean assembly gap of 3μm,and decreased to 0.5 kPa(0.073 psig)at a mean assembly gap of 240μm.The effect of radial misalignment on the efficacy of the gasketless seals was tested and no significant effect was observed.This may be a function of how the liquid bridges are formed during the priming of the chip,but additional research is required to test that hypothesis.
