A liquid Li divertor is a promising alternative for future fusion devices.In this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capil...A liquid Li divertor is a promising alternative for future fusion devices.In this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capillary structure.At a steady-state heat load of 10 MW m^(-2),the thermal stress of the tungsten target is within the bearing range of tungsten by finite-element simulation.In order to evaluate the wicking ability of the capillary structure,the wicking process at 600℃ was simulated by FLUENT.The result was identical to that of the corresponding experiments.Within 1 s,liquid lithium was wicked to the target surface by the capillary structure of the target and quickly spread on the target surface.During the wicking process,the average wicking mass rate of lithium should reach 0.062 g s^(-1),which could even supplement the evaporation requirement of liquid lithium under an environment>950℃.Irradiation experiments under different plasma discharge currents were carried out in a linear plasma device(SCU-PSI),and the evolution of the vapor cloud during plasma irradiation was analyzed.It was found that the target temperature tends to plateau despite the gradually increased input current,indicating that the vapor shielding effect is gradually enhanced.The irradiation experiment also confirmed that the 3D-printed tungsten structure has better heat consumption performance than a tungsten mesh structure or multichannel structure.These results reveal the application potential and feasibility of a 3D-printed porous capillary structure in plasma-facing components and provide a reference for further liquid-solid combined target designs.展开更多
Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue regeneration.In this study,we developed a poly(2-hydroxyethyl me...Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue regeneration.In this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHEMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PEDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)printing.The presence of the NPs was critical as they altered the rheological properties during printing.However,all samples exhibited suitable shear thinning properties,allowing for the development of an optimized processing window for 3D printing.Samples were 3D printed into pre-determined disk-shaped configurations of 2 and 10 mm in height and diameter,respectively.We observed that the NPs disrupted the gel crosslinking efficiencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 kPa.The conductivity of the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/cm.In vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHEMA-co-MAA NP hydrogels yielded high cellular viability and proliferation rates.Finally,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels affected bacterial growth.Taken together,these materials show promise for various TE strategies.展开更多
In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we dev...In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we developed an Mg-1Ca/polycaprolactone(Mg-1Ca/PCL)composite scaffolds to overcome these limitations.We used a melt blending method to prepare Mg-1Ca/PCL composites with Mg-1Ca alloy powder mass ratios of 5,10,and 20 wt%.Porous scaffolds with controlled macro-and microstructure were printed using the fused deposition modeling method.We explored the mechanical strength,biocompatibility,osteogenesis performance,and molecular mechanism of the Mg-1Ca/PCL composites.The 5 and 10 wt%Mg-1Ca/PCL composites were found to have good biocompatibility.Moreover,they promoted the mechanical strength,proliferation,adhesion,and osteogenic differentiation of human bone marrow stem cells(hBMSCs)of pure PCL.In vitro degradation experiments revealed that the composite material stably released Mg_(2)+ions for a long period;it formed an apatite layer on the surface of the scaffold that facilitated cell adhesion and growth.Microcomputed tomography and histological analysis showed that both 5 and 10 wt%Mg-1Ca/PCL composite scaffolds promoted bone regeneration bone defects.Our results indicated that the Wnt/β-catenin pathway was involved in the osteogenic effect.Therefore,Mg-1Ca/PCL composite scaffolds are expected to be a promising bone regeneration material for clinical application.Statement of significance:Bone tissue engineering scaffolds have promising applications in the regeneration of critical-sized bone defects.However,there remain many limitations in the materials and manufacturing methods used to fabricate scaffolds.This study shows that the developed Ma-1Ca/PCL composites provides scaffolds with suitable degradation rates and enhanced boneformation capabilities.Furthermore,the fused deposition modeling method allows precise control of the macroscopic morphology and microscopic porosity of the scaffold.The obtained porous scaffolds can significantly promote the regeneration of bone defects.展开更多
Metal-organic framework(MOF)and covalent organic framework(COF)are a huge group of advanced porous materials exhibiting attractive and tunable microstructural features,such as large surface area,tunable pore size,and ...Metal-organic framework(MOF)and covalent organic framework(COF)are a huge group of advanced porous materials exhibiting attractive and tunable microstructural features,such as large surface area,tunable pore size,and functional surfaces,which have significant values in various application areas.The emerging 3D printing technology further provides MOF and COFs(M/COFs)with higher designability of their macrostructure and demonstrates large achievements in their performance by shaping them into advanced 3D monoliths.However,the currently available 3D printing M/COFs strategy faces a major challenge of severe destruction of M/COFs’microstructural features,both during and after 3D printing.It is envisioned that preserving the microstructure of M/COFs in the 3D-printed monolith will bring a great improvement to the related applications.In this overview,the 3D-printed M/COFs are categorized into M/COF-mixed monoliths and M/COF-covered monoliths.Their differences in the properties,applications,and current research states are discussed.The up-to-date advancements in paste/scaffold composition and printing/covering methods to preserve the superior M/COF microstructure during 3D printing are further discussed for the two types of 3D-printed M/COF.Throughout the analysis of the current states of 3D-printed M/COFs,the expected future research direction to achieve a highly preserved microstructure in the 3D monolith is proposed.展开更多
Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of...Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue regeneration.We experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and differentiation.The resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)printing.Morphological studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural stability.The scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue engineering.The tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of gelatin.The enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue regeneration.In vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold surface.In addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its potential for use in bone-tissue engineering.展开更多
Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint prostheses.In this study,we created a polyether-ether-ketone(PEEK)joint prosthesis ...Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint prostheses.In this study,we created a polyether-ether-ketone(PEEK)joint prosthesis using fused filament fabrication and investigated the effects of printing orientation on its tribological properties using a pin-on-plate tribometer in 25% newborn calf serum.An ultrahigh molecular weight polyethylene transfer film is formed on the surface of PEEK due to the mechanical capture of wear debris by the 3D-printed groove morphology,which is significantly impacted by the printing orientation of PEEK.When the printing orientation was parallel to the sliding direction of friction,the number and size of the transfer film increased due to higher steady stress.This transfer film protected the matrix and reduced the friction coefficient and wear rate of friction pairs by 39.13%and 74.33%,respectively.Furthermore,our findings provide a novel perspective regarding the role of printing orientation in designing knee prostheses,facilitating its practical applications.展开更多
Large bone defect regeneration has always been recognized as a challenging clinical problem due to the difficulty of revascularization.Conventional treatments exhibit certain inherent disadvantages(e.g.,secondary inju...Large bone defect regeneration has always been recognized as a challenging clinical problem due to the difficulty of revascularization.Conventional treatments exhibit certain inherent disadvantages(e.g.,secondary injury,immunization,and potential infections).However,three-dimensional(3D)printing technology as an emerging field can serve as an effective approach to achieve satisfactory revascularization while making up for the above limitations.A wide variety of methods can be used to facilitate blood supply during the design of a 3D-printed scaffold.Importantly,the scaffold structure lays a foundation for the entire printing object;any method to promote angiogenesis can be effective only if it is based on well-designed scaffolds.In this review,different designs related to angiogenesis are summarized by collecting the literature from recent years.The 3D-printed scaffolds are classified into four major categories and discussed in detail,from elementary porous scaffolds to the most advanced bone-like scaffolds.Finally,structural design suggestions to achieve rapid angiogenesis are proposed by analyzing the above architectures.This review can provide a reference for organizations or individual academics to achieve improved bone defect repair and regeneration using 3D printing.展开更多
Three-dimensional(3D) printing provides a promising way to fabricate biodegradable scaffolds with designer architectures for the regeneration of various tissues.However,the existing3D-printed scaffolds commonly suffer...Three-dimensional(3D) printing provides a promising way to fabricate biodegradable scaffolds with designer architectures for the regeneration of various tissues.However,the existing3D-printed scaffolds commonly suffer from weak cell-scaffold interactions and insufficient cell organizations due to the limited resolution of the 3D-printed features.Here,composite scaffolds with mechanically-robust frameworks and aligned nanofibrous architectures are presented and hybrid manufactured by combining techniques of 3D printing,electrospinning,and unidirectional freeze-casting.It was found that the composite scaffolds provided volume-stable environments and enabled directed cellular infiltration for tissue regeneration.In particular,the nanofibrous architectures with aligned micropores served as artificial extracellular matrix materials and improved the attachment,proliferation,and infiltration of cells.The proposed scaffolds can also support the adipogenic maturation of adipose-derived stem cells(ADSCs)in vitro.Moreover,the composite scaffolds were found to guide directed tissue infiltration and promote nearby neovascularization when implanted into a subcutaneous model of rats,and the addition of ADSCs further enhanced their adipogenic potential.The presented hybrid manufacturing strategy might provide a promising way to produce additional topological cues within 3D-printed scaffolds for better tissue regeneration.展开更多
For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining techniq...For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining technique is undoubtedly the most suitable mining method.The downward filling mining technique may eliminate the troubles relating to poor ore deposit conditions,such as production safety,ore loss rate,and depletion rate.However,in this technique,the safety of the artificial roof of the next stratum is of paramount importance.Cementitious tailings backfilling(CTB)that is not sufficiently cemented and causes collapses could threaten ore production.This paper explores a diamond-shaped composite structure to mimic the stability of a glued false roof in an actual infill mine based on the recently emerged three-dimensional(3D)printing technology.Experimental means such as three-point bending and digital image correlation(DIC)techniques were used to explore the flexural characteristics of 3D construction specimens and CTB combinations with different cement/tailings weight ratios at diverse layer heights.The results show that the 3D structure with a 14-mm ply height and CTB has strong flexural characteristics,with a maximum deflection value of 30.1 mm,while the 3D-printed rhomboid polymer(3D-PRP)structure with a 26-mm ply height is slightly worse in terms of flexural strength characteristics,but it has a higher maximum flexural strength of 2.83 MPa.A combination of 3D structure and CTB has more unique mechanical properties than CTB itself.This research work offers practical knowledge on the artificial roof performance of the downward layered filling mining technique and builds a scientific knowledge base regarding the successful application of CTB material in mines.展开更多
There are various clinical treatments for traumatic brain injury,including surgery,drug therapy,and rehabilitation therapy;howeve r,the therapeutic effects are limited.Scaffolds combined with exosomes represent a prom...There are various clinical treatments for traumatic brain injury,including surgery,drug therapy,and rehabilitation therapy;howeve r,the therapeutic effects are limited.Scaffolds combined with exosomes represent a promising but challenging method for improving the repair of traumatic brain injury.In this study,we determined the ability of a novel 3D-printed collagen/chitosan scaffold loaded with exosomes derived from neural stem cells pretreated with insulin-like growth factor-1(3D-CC-INEXOS) to improve traumatic brain injury repair and functional recove ry after traumatic brain injury in rats.Composite scaffolds comprising collagen,chitosan,and exosomes derived from neural stem cells pretreated with insulin-like growth fa ctor-1(INEXOS) continuously released exosomes for 2weeks.Transplantation of 3D-CC-INExos scaffolds significantly improved motor and cognitive functions in a rat traumatic brain injury model,as assessed by the Morris water maze test and modified neurological seve rity scores.In addition,immunofluorescence staining and transmission electron microscopy showed that3D-CC-INExos implantation significantly improved the recove ry of damaged nerve tissue in the injured area.In conclusion,this study suggests that transplanted3D-CC-INExos scaffolds might provide a potential strategy for the treatment of traumatic brain injury and lay a solid foundation for clinical translation.展开更多
Nuclear safety is a global growing concern,where ionizing radiation(IR)is a major injury factor resulting in serious damage to organisms.The detection of IR is usually conducted with physical dosimeters;however,biolog...Nuclear safety is a global growing concern,where ionizing radiation(IR)is a major injury factor resulting in serious damage to organisms.The detection of IR is usually conducted with physical dosimeters;however,biological IR detection methods are deficient.Here,a living composite hydrogel consisting of engineered bacteria and gelatin/sodium alginate was 3D-printed for the biological detection of IR.Three strains of PrecA::egfp gene circuit-containing engineered Escherichia coli were constructed with IR-dependent fluorescence,and the DH5αstrain was finally selected due to its highest radiation response and fluorescence.Engineered bacteria were loaded in a series of gelatin/sodium alginate matrix hydrogels with different rheology,3D printability and bacterial applicability.A high-gelatin-content hydrogel containing 10%gelatin/1.25%sodium alginatewas optimal.The optimal living composite hydrogelwas 3D-printedwith the special bioink,which reported significant green fluorescence underγ-ray radiation.The living composite hydrogel provides a biological strategy for the detection of environmental ionizing radiation.展开更多
BACKGROUND Total hip arthroplasty is a common surgical treatment for elderly patients with osteoporosis,particularly in postmenopausal women.In such cases,highly porous acetabular components are a favorable option in ...BACKGROUND Total hip arthroplasty is a common surgical treatment for elderly patients with osteoporosis,particularly in postmenopausal women.In such cases,highly porous acetabular components are a favorable option in achieving osseointegration.However,further discussion is needed if use of such acetabular components is justified under the condition of normal bone mass.AIM To determine the features of osseointegration of two different types of titanium implants[3-dimensional(3D)-printed and plasma-coated titanium implants]in bone tissue of a distal metaphysis in a rat femur model.METHODS This study was performed on 20 white male laboratory rats weighing 300-350 g aged 6 mo.Rats were divided into two groups of 10 animals,which had two different types of implants were inserted into a hole defect(2×3 mm)in the distal metaphysis of the femur:GroupⅠ:3D-printed titanium implant(highly porous);GroupⅡ:Plasma-coated titanium implant.After 45 and 90 d following surgery,the rats were sacrificed,and their implanted femurs were extracted for histological examination.The relative perimeter(%)of bone trabeculae[bone-implant contact(BIC%)]and bone marrow surrounding the titanium implants was measured.RESULTS Trabecular bone tissue was formed on the 45th day after implantation around the implants regardless of their type.45 d after surgery,group I(3D-printed titanium implant)and groupⅡ(plasma-coated titanium implant)did not differ in BIC%(83.51±8.5 vs 84.12±1.73;P=0.838).After 90 d,the BIC%was higher in group I(87.04±6.99 vs 81.24±7.62;P=0.049),compared to groupⅡ.The relative perimeter of the bone marrow after 45 d did not differ between groups and was 16.49%±8.58%for groupⅠ,and 15.88%±1.73%for groupⅡ.Futhermore,after 90 d,in groupⅠthe relative perimeter of bone marrow was 1.4 times smaller(12.96±6.99 vs 18.76±7.62;P=0.049)compared to the relative perimeter of bone marrow in groupⅡ.CONCLUSION The use of a highly porous titanium implant,manufactured with 3D printing,for acetabular components provides increased osseointegration compared to a plasma-coated titanium implant.展开更多
To improve the strength of carbon fiber(CF) reinforced Polycaprolactam(PA6) composites, controlled amounts of carbon nanotubes(CNTs) were grafted onto the surface of CF to prepare the hybrid reinforcement(HR). We used...To improve the strength of carbon fiber(CF) reinforced Polycaprolactam(PA6) composites, controlled amounts of carbon nanotubes(CNTs) were grafted onto the surface of CF to prepare the hybrid reinforcement(HR). We used HR to fabricate laminate and H-sample to test the interfacial bonding strength(IBS) of the composites by means of a novel process called three-dimensional printed molding(3 D-PM). By using the melt drop printing method, we measured the contact angles between PA6 and CF(without sizing) and between PA6 and HR. The IBS and the mechanical properties of the composites were obtained by the tensile test. The experimental result indicated that CF grafted by 0.25% weight fraction of CNT or more could develop a special microstructure similar to the micro-pits on the surface of CF, which improved the wettability of CF and PA6 due to the increased surface area and the roughness of CF. When the weight fraction of CNT reached 0.25%, the IBS increased by 41.8%, the tensile strength by 130%, and the interfacial shear strength(IFSS) by 238%. The interfacial dimple fracture was observed by Scanning Electron Microscope(SEM), which revealed that the composites were able to absorb more deforming energy before fracture. The modified surface microstructure of CF would prevent crack propagation at the interface and increase the mechanical properties of thermoplastic composites(TPCs).展开更多
Living and/or non-living animal models are often used as stimuli to observe the behavioral responses of the target animals.In the past,parasites,predators,and harmless controls have been used to test host anti-parasit...Living and/or non-living animal models are often used as stimuli to observe the behavioral responses of the target animals.In the past,parasites,predators,and harmless controls have been used to test host anti-parasitism defense behavior,and their taxidermy specimens have been widely used as a set of standard methods for the study of avian brood parasitism.In recent years,with the rapid development of 3D-printing technology,3D-printed bird models are expected to be applied as a standard method in the study of avian brood parasitism.To evaluate the use of 3D-printed models,this study tests the reaction of Oriental Reed Warbler(Acrocephalus orientalis)towards predators,parasites,or controls,and compares the reaction among different nest intruders and between taxidermy specimens and 3D-printed animal models.It was found that the Oriental Reed Warbler responded most aggressively to the parasite,followed by predator,and finally the control;the results were consistent between the reaction to taxidermy specimens and 3D-printed animal models,indicating that 3D-printed models could serve as a substitute for taxidermy specimens.We propose a series of advantages of using 3D-printed models and suggest them to be a standard method for widespread use in future studies of avian brood parasitism.展开更多
In the current study poly(lactic acid)PLA composites with a 3 wt%and 5 wt%of nanofibrillated cellulose(NFC)were produced by 3D-printing method.An enzymatic pretreatment coupled with mechanical fibrillation in a twin s...In the current study poly(lactic acid)PLA composites with a 3 wt%and 5 wt%of nanofibrillated cellulose(NFC)were produced by 3D-printing method.An enzymatic pretreatment coupled with mechanical fibrillation in a twin screw extruder was used to produce high consistency NFC.Scanning electron microscopy(SEM)equipped with Fibermetric software,FASEP fiber length distribution analysis,Furrier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA),tensile tests,impact tests and differential scanning calorimetry were used to characterize NFC and PLA/NFC composites.The results of the fiber length and width measurements together with the results of the SEM analysis showed that enzymatic hydrolysis coupled with a twin screw extrusion could effectively reduce the diameter and length of cellulose fibers.The produced NFC consisted of microand nanosized fibers entangled in a characteristic 3D-network.Based on the FT-IR analysis,no new bonds were formed during the enzymatic hydrolysis or fibrillation process.The TGA analysis confirmed that produced NFC can be used in hightemperature extrusion processing without NFC degradation.During the PLA/NFC composites preparation the NFC agglomerates were formed,which negatively influenced PLA/NFC composites impact properties.The slightly improved tensile strength and elastic modulus were reported for all composites when compared to the neat PLA.The elongation at break was not affected by the NFC addition.No significant differences in thermal stability were detectable among composites nor in comparation with the neat PLA.However,the crystallinity degree of the composite containing 5 wt%NFC was increased in respect to the neat PLA.展开更多
AIM To evaluate a 3 D-printed coplanar template for iodine-125 seed implantation therapy in patients with pancreatic cancer. METHODS A retrospective analysis of our database was performed, and a total of 25 patients w...AIM To evaluate a 3 D-printed coplanar template for iodine-125 seed implantation therapy in patients with pancreatic cancer. METHODS A retrospective analysis of our database was performed, and a total of 25 patients with pancreatic cancer who underwent iodine-125 seed implantation between January 2014 and November 2017 were analyzed. Of these, 12 implantations were assisted by a 3 D-printed coplanar template(group A), and 13 implantations performed freehand were selected as a control group(group B). A 3 D coplanar template was designed and printed according to a preoperative CT scan and treatment planning system. The iodine-125 seeds were then implanted using the template as a guide. Dosimetric verification was performed after implantation. Pre-and postoperative D90, V100, and V150 were calculated. The success rate of iodine-125 seed implantation, dosimetric parameters, and complications were analyzed and compared between the two groups.RESULTS Iodine-125 seed implantation was successfully performed in both groups. In group A, the median pre-and postoperative D90 values were 155.32 ± 8.05 Gy and 154.82 ± 16.43 Gy, respectively; the difference between these values was minimal and not statistically significant(P > 0.05). Postoperative V100 and V150 were 91.05% ± 4.06% and 64.54% ± 13.40%, respectively, which met the treatment requirement. A better dosimetric parameter was observed in group A than in group B, and the difference was statistically significant(V100: 91.05% ± 4.06% vs 72.91% ± 13.78%, P < 0.05). No major procedure-related complications were observed in either group. For group A, mild hemorrhage was observed in 1 patient with a peritoneal local hematoma due to mesenteric vein damage from the iodine-125 seed implantation needle. The hematoma resolved spontaneously without treatment. Postoperative blood amylase levels remained within the normal range for all patients.CONCLUSION A 3 D-printed coplanar template appears to be a safe and effective iodine-125 seed implantation guidance tool to improve implantation accuracy and optimize dosimetric distribution.展开更多
Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such a...Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such as "fistula patch" and vacuumassisted closure therapy have been applied to prevent contamination of open abdominal wounds by intestinal fistula drainage. However, failures are encountered due to high-output fistula and anatomical complexity. Here, we report 3 D-printed patient-personalized fistula stent for ECF treatment based on 3 D reconstruction of the fistula image. Subsequent follow-up demonstrated that this stent was well-implanted and effective to reduce the volume of enteric fistula effluent.展开更多
With the rapid development of integrated and miniaturized electronics,the planar energy storage devices with high capacitance and energy density are in enormous demand.Hence,the advanced manufacture and fast fabricati...With the rapid development of integrated and miniaturized electronics,the planar energy storage devices with high capacitance and energy density are in enormous demand.Hence,the advanced manufacture and fast fabrication of microscale planar energy units are of great significance.Herein,we develop aqueous planar micro-supercapacitors(MSCs) with ultrahigh areal capacitance and energy density via an efficient all-3 D-printing strategy,which can directly extrude the active material ink and gel electrolyte onto the substrate to prepare electrochemical energy storage devices.Both the printed active carbon/exfoliated graphene(AC/EG) electrode ink and electrolyte gel are highly processable with outstanding conductivity(~97 S cm^(-1) of electrode;-34.8 mS cm^(-1) of electrolyte),thus benefiting the corresponding shaping and electrochemical performances.Furthermore,the 3 D-printed symmetric MSCs can be operated stably at a high voltage up to 2.0 V in water-in-salt gel electrolyte,displaying ultrahigh areal capacitance of2381 mF cm^(-2) and exceptional energy density of 331 μWh cm^(-2),superior to previous printed micro energy units.In addition,we can further tailor the integrated 3 D-printed MSCs in parallel and series with various voltage and current outputs,enabling metal-free interconnection.Therefore,our all-3 D-printed MSCs place a great potential in developing high-power micro-electronics fabrication and integration.展开更多
Three-dimensional(3D)-printed magnetic soft architectures have attracted extensive attention and research from the engineering and material fields.The force-driven shape deformation of such architectures causes a chan...Three-dimensional(3D)-printed magnetic soft architectures have attracted extensive attention and research from the engineering and material fields.The force-driven shape deformation of such architectures causes a change in the magnetic field distribution,indicating the capability to convert mechanical energy to electricity.Herein,we fabricate a flexible superhydrophobic and magnetic device by integrating two kinds of 3D printing approaches.The 3D-printed magnetic device(3DMD)exhibits a long-term stable mechanoelectrical conversion capacity under consecutive water droplet dripping.The output current of the 3DMD is higher than that of records in the existing literature.Combined with Maxwell numerical simulation,the mechanoelectrical conversion mechanism of the 3DMD is investigated,further guiding regulation of the diverse parameters.Moreover,three 3DMDs are integrated to light up a commercial light-emitting diode(LED)by a stream of collected rainwater.Such a combined design incorporating energy conversion is believed to promisingly motive advances in the 3D printing field.展开更多
Combining 3D printing with precursor-derived ceramic for fabricating electromagnetic(EM) wave-absorbing metamaterials has attracted great attention. This study presents a novel ultraviolet-curable polysiloxane precurs...Combining 3D printing with precursor-derived ceramic for fabricating electromagnetic(EM) wave-absorbing metamaterials has attracted great attention. This study presents a novel ultraviolet-curable polysiloxane precursor for digital light processing(DLP) 3D printing to fabricate ceramic parts with complex geometry, no cracks and linear shrinkage. Guiding with the principles of impedance matching, attenuation, and effective-medium theory, we design a crosshelix-array metamaterial model based on the complex permittivity constant of precursor-derived ceramics. The corresponding ceramic metamaterials can be successfully prepared by DLP printing and subsequent pyrolysis process, achieving a low reflection coefficient and a wide effective absorption bandwidth in the X-band even under high temperature. This is a general method that can be extended to other bands, which can be realized by merely adjusting the unit structure of meta-materials. This strategy provides a novel and effective avenue to achieve “target-design-fabricating” ceramic metamaterials, and it exposes the downstream applications of highly efficient and broad EM wave-absorbing materials and structures with great potential applications.展开更多
基金funded by the China Postdoctoral Science Foundation(No.2019M663487)the National Key Research and Development Program of China(No.2022YFE03130000)。
文摘A liquid Li divertor is a promising alternative for future fusion devices.In this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capillary structure.At a steady-state heat load of 10 MW m^(-2),the thermal stress of the tungsten target is within the bearing range of tungsten by finite-element simulation.In order to evaluate the wicking ability of the capillary structure,the wicking process at 600℃ was simulated by FLUENT.The result was identical to that of the corresponding experiments.Within 1 s,liquid lithium was wicked to the target surface by the capillary structure of the target and quickly spread on the target surface.During the wicking process,the average wicking mass rate of lithium should reach 0.062 g s^(-1),which could even supplement the evaporation requirement of liquid lithium under an environment>950℃.Irradiation experiments under different plasma discharge currents were carried out in a linear plasma device(SCU-PSI),and the evolution of the vapor cloud during plasma irradiation was analyzed.It was found that the target temperature tends to plateau despite the gradually increased input current,indicating that the vapor shielding effect is gradually enhanced.The irradiation experiment also confirmed that the 3D-printed tungsten structure has better heat consumption performance than a tungsten mesh structure or multichannel structure.These results reveal the application potential and feasibility of a 3D-printed porous capillary structure in plasma-facing components and provide a reference for further liquid-solid combined target designs.
基金research conducted with the financial support of Science Foundation Ireland under the SFI Research Infrastructure Programme (21/RI/9831)the funding provided by the Irish Research Council through the Irish Research Council Enterprise Partnership Scheme with Johnson and Johnson (EPSPG/2020/78)
文摘Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue regeneration.In this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHEMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PEDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)printing.The presence of the NPs was critical as they altered the rheological properties during printing.However,all samples exhibited suitable shear thinning properties,allowing for the development of an optimized processing window for 3D printing.Samples were 3D printed into pre-determined disk-shaped configurations of 2 and 10 mm in height and diameter,respectively.We observed that the NPs disrupted the gel crosslinking efficiencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 kPa.The conductivity of the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/cm.In vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHEMA-co-MAA NP hydrogels yielded high cellular viability and proliferation rates.Finally,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels affected bacterial growth.Taken together,these materials show promise for various TE strategies.
基金supported by the National Key R&D Program of China[grant number 2021YFC2400700]the National Natural Science Foundation of China[grant numbers 82170929,81970908 and 81771039].
文摘In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we developed an Mg-1Ca/polycaprolactone(Mg-1Ca/PCL)composite scaffolds to overcome these limitations.We used a melt blending method to prepare Mg-1Ca/PCL composites with Mg-1Ca alloy powder mass ratios of 5,10,and 20 wt%.Porous scaffolds with controlled macro-and microstructure were printed using the fused deposition modeling method.We explored the mechanical strength,biocompatibility,osteogenesis performance,and molecular mechanism of the Mg-1Ca/PCL composites.The 5 and 10 wt%Mg-1Ca/PCL composites were found to have good biocompatibility.Moreover,they promoted the mechanical strength,proliferation,adhesion,and osteogenic differentiation of human bone marrow stem cells(hBMSCs)of pure PCL.In vitro degradation experiments revealed that the composite material stably released Mg_(2)+ions for a long period;it formed an apatite layer on the surface of the scaffold that facilitated cell adhesion and growth.Microcomputed tomography and histological analysis showed that both 5 and 10 wt%Mg-1Ca/PCL composite scaffolds promoted bone regeneration bone defects.Our results indicated that the Wnt/β-catenin pathway was involved in the osteogenic effect.Therefore,Mg-1Ca/PCL composite scaffolds are expected to be a promising bone regeneration material for clinical application.Statement of significance:Bone tissue engineering scaffolds have promising applications in the regeneration of critical-sized bone defects.However,there remain many limitations in the materials and manufacturing methods used to fabricate scaffolds.This study shows that the developed Ma-1Ca/PCL composites provides scaffolds with suitable degradation rates and enhanced boneformation capabilities.Furthermore,the fused deposition modeling method allows precise control of the macroscopic morphology and microscopic porosity of the scaffold.The obtained porous scaffolds can significantly promote the regeneration of bone defects.
基金the support by National Research Foundation of Singapore(NRF,Project:NRF-CRP262021RS-0002),for research conducted at the National University of Singapore(NUS)。
文摘Metal-organic framework(MOF)and covalent organic framework(COF)are a huge group of advanced porous materials exhibiting attractive and tunable microstructural features,such as large surface area,tunable pore size,and functional surfaces,which have significant values in various application areas.The emerging 3D printing technology further provides MOF and COFs(M/COFs)with higher designability of their macrostructure and demonstrates large achievements in their performance by shaping them into advanced 3D monoliths.However,the currently available 3D printing M/COFs strategy faces a major challenge of severe destruction of M/COFs’microstructural features,both during and after 3D printing.It is envisioned that preserving the microstructure of M/COFs in the 3D-printed monolith will bring a great improvement to the related applications.In this overview,the 3D-printed M/COFs are categorized into M/COF-mixed monoliths and M/COF-covered monoliths.Their differences in the properties,applications,and current research states are discussed.The up-to-date advancements in paste/scaffold composition and printing/covering methods to preserve the superior M/COF microstructure during 3D printing are further discussed for the two types of 3D-printed M/COF.Throughout the analysis of the current states of 3D-printed M/COFs,the expected future research direction to achieve a highly preserved microstructure in the 3D monolith is proposed.
基金The authors are thankful to Ministry of Human Resource Development(presently Ministry of Education),Government of India,New Delhi,for providing research facility by sanctioning Center of Excellence(F.No.5-6/2013-TS VII)in Tissue Engineering and Center of Excellence in Orthopedic Tissue Engineering and Rehabilitation funded by World Bank under TEQIP-II.
文摘Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering application.The present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue regeneration.We experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and differentiation.The resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)printing.Morphological studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural stability.The scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue engineering.The tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of gelatin.The enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue regeneration.In vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold surface.In addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its potential for use in bone-tissue engineering.
基金This study was supported by the following funds:National Key R&D Program of China(No.2018YFE0207900)Program for Innovation Team of Shaanxi Province(No.2023-CXTD-17)+5 种基金Program of the National Natural Science Foundation of China(No.51835010)Key R&D Program of Guangdong Province(No.2018B090906001)Natural Science Basic Research Program of Shaanxi Province(No.2022JQ-378)China Postdoctoral Science Foundation(No.2020M683458)Fundamental Research Funds for the Central Universities(8)Youth Innovation Team of Shaanxi Universities.
文摘Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint prostheses.In this study,we created a polyether-ether-ketone(PEEK)joint prosthesis using fused filament fabrication and investigated the effects of printing orientation on its tribological properties using a pin-on-plate tribometer in 25% newborn calf serum.An ultrahigh molecular weight polyethylene transfer film is formed on the surface of PEEK due to the mechanical capture of wear debris by the 3D-printed groove morphology,which is significantly impacted by the printing orientation of PEEK.When the printing orientation was parallel to the sliding direction of friction,the number and size of the transfer film increased due to higher steady stress.This transfer film protected the matrix and reduced the friction coefficient and wear rate of friction pairs by 39.13%and 74.33%,respectively.Furthermore,our findings provide a novel perspective regarding the role of printing orientation in designing knee prostheses,facilitating its practical applications.
基金supported by the Zhejiang Province Key Research and Development Program(No.2021C03059)。
文摘Large bone defect regeneration has always been recognized as a challenging clinical problem due to the difficulty of revascularization.Conventional treatments exhibit certain inherent disadvantages(e.g.,secondary injury,immunization,and potential infections).However,three-dimensional(3D)printing technology as an emerging field can serve as an effective approach to achieve satisfactory revascularization while making up for the above limitations.A wide variety of methods can be used to facilitate blood supply during the design of a 3D-printed scaffold.Importantly,the scaffold structure lays a foundation for the entire printing object;any method to promote angiogenesis can be effective only if it is based on well-designed scaffolds.In this review,different designs related to angiogenesis are summarized by collecting the literature from recent years.The 3D-printed scaffolds are classified into four major categories and discussed in detail,from elementary porous scaffolds to the most advanced bone-like scaffolds.Finally,structural design suggestions to achieve rapid angiogenesis are proposed by analyzing the above architectures.This review can provide a reference for organizations or individual academics to achieve improved bone defect repair and regeneration using 3D printing.
基金financially supported by the National Key Research and Development Program of China(2018YFA0703003)the National Natural Science Foundation of China (52125501)+2 种基金the Key Research Project of Shaanxi Province (2021LLRH-08,2021GXLH-Z-028)the Program for Innovation Team of Shaanxi Province (2023-CX-TD-17)the Fundamental Research Funds for the Central Universities。
文摘Three-dimensional(3D) printing provides a promising way to fabricate biodegradable scaffolds with designer architectures for the regeneration of various tissues.However,the existing3D-printed scaffolds commonly suffer from weak cell-scaffold interactions and insufficient cell organizations due to the limited resolution of the 3D-printed features.Here,composite scaffolds with mechanically-robust frameworks and aligned nanofibrous architectures are presented and hybrid manufactured by combining techniques of 3D printing,electrospinning,and unidirectional freeze-casting.It was found that the composite scaffolds provided volume-stable environments and enabled directed cellular infiltration for tissue regeneration.In particular,the nanofibrous architectures with aligned micropores served as artificial extracellular matrix materials and improved the attachment,proliferation,and infiltration of cells.The proposed scaffolds can also support the adipogenic maturation of adipose-derived stem cells(ADSCs)in vitro.Moreover,the composite scaffolds were found to guide directed tissue infiltration and promote nearby neovascularization when implanted into a subcutaneous model of rats,and the addition of ADSCs further enhanced their adipogenic potential.The presented hybrid manufacturing strategy might provide a promising way to produce additional topological cues within 3D-printed scaffolds for better tissue regeneration.
基金financially supported by the National Key Research and Development Program of China(No.2022YFC2905004)the National Natural Science Foundation of China(No.51804017)。
文摘For mines with poor ore bodies and surrounding rocks,the general mining method does not allow the ore to be extracted from underground safely and efficiently.For these mines,the downward layered filling mining technique is undoubtedly the most suitable mining method.The downward filling mining technique may eliminate the troubles relating to poor ore deposit conditions,such as production safety,ore loss rate,and depletion rate.However,in this technique,the safety of the artificial roof of the next stratum is of paramount importance.Cementitious tailings backfilling(CTB)that is not sufficiently cemented and causes collapses could threaten ore production.This paper explores a diamond-shaped composite structure to mimic the stability of a glued false roof in an actual infill mine based on the recently emerged three-dimensional(3D)printing technology.Experimental means such as three-point bending and digital image correlation(DIC)techniques were used to explore the flexural characteristics of 3D construction specimens and CTB combinations with different cement/tailings weight ratios at diverse layer heights.The results show that the 3D structure with a 14-mm ply height and CTB has strong flexural characteristics,with a maximum deflection value of 30.1 mm,while the 3D-printed rhomboid polymer(3D-PRP)structure with a 26-mm ply height is slightly worse in terms of flexural strength characteristics,but it has a higher maximum flexural strength of 2.83 MPa.A combination of 3D structure and CTB has more unique mechanical properties than CTB itself.This research work offers practical knowledge on the artificial roof performance of the downward layered filling mining technique and builds a scientific knowledge base regarding the successful application of CTB material in mines.
基金supported by the National Major Scientific and Technological Special Project for Significant New Drugs Development,No.2019ZX09301-147 (to LXZ)。
文摘There are various clinical treatments for traumatic brain injury,including surgery,drug therapy,and rehabilitation therapy;howeve r,the therapeutic effects are limited.Scaffolds combined with exosomes represent a promising but challenging method for improving the repair of traumatic brain injury.In this study,we determined the ability of a novel 3D-printed collagen/chitosan scaffold loaded with exosomes derived from neural stem cells pretreated with insulin-like growth factor-1(3D-CC-INEXOS) to improve traumatic brain injury repair and functional recove ry after traumatic brain injury in rats.Composite scaffolds comprising collagen,chitosan,and exosomes derived from neural stem cells pretreated with insulin-like growth fa ctor-1(INEXOS) continuously released exosomes for 2weeks.Transplantation of 3D-CC-INExos scaffolds significantly improved motor and cognitive functions in a rat traumatic brain injury model,as assessed by the Morris water maze test and modified neurological seve rity scores.In addition,immunofluorescence staining and transmission electron microscopy showed that3D-CC-INExos implantation significantly improved the recove ry of damaged nerve tissue in the injured area.In conclusion,this study suggests that transplanted3D-CC-INExos scaffolds might provide a potential strategy for the treatment of traumatic brain injury and lay a solid foundation for clinical translation.
基金supported by the Special Program for Capability Promotion
文摘Nuclear safety is a global growing concern,where ionizing radiation(IR)is a major injury factor resulting in serious damage to organisms.The detection of IR is usually conducted with physical dosimeters;however,biological IR detection methods are deficient.Here,a living composite hydrogel consisting of engineered bacteria and gelatin/sodium alginate was 3D-printed for the biological detection of IR.Three strains of PrecA::egfp gene circuit-containing engineered Escherichia coli were constructed with IR-dependent fluorescence,and the DH5αstrain was finally selected due to its highest radiation response and fluorescence.Engineered bacteria were loaded in a series of gelatin/sodium alginate matrix hydrogels with different rheology,3D printability and bacterial applicability.A high-gelatin-content hydrogel containing 10%gelatin/1.25%sodium alginatewas optimal.The optimal living composite hydrogelwas 3D-printedwith the special bioink,which reported significant green fluorescence underγ-ray radiation.The living composite hydrogel provides a biological strategy for the detection of environmental ionizing radiation.
文摘BACKGROUND Total hip arthroplasty is a common surgical treatment for elderly patients with osteoporosis,particularly in postmenopausal women.In such cases,highly porous acetabular components are a favorable option in achieving osseointegration.However,further discussion is needed if use of such acetabular components is justified under the condition of normal bone mass.AIM To determine the features of osseointegration of two different types of titanium implants[3-dimensional(3D)-printed and plasma-coated titanium implants]in bone tissue of a distal metaphysis in a rat femur model.METHODS This study was performed on 20 white male laboratory rats weighing 300-350 g aged 6 mo.Rats were divided into two groups of 10 animals,which had two different types of implants were inserted into a hole defect(2×3 mm)in the distal metaphysis of the femur:GroupⅠ:3D-printed titanium implant(highly porous);GroupⅡ:Plasma-coated titanium implant.After 45 and 90 d following surgery,the rats were sacrificed,and their implanted femurs were extracted for histological examination.The relative perimeter(%)of bone trabeculae[bone-implant contact(BIC%)]and bone marrow surrounding the titanium implants was measured.RESULTS Trabecular bone tissue was formed on the 45th day after implantation around the implants regardless of their type.45 d after surgery,group I(3D-printed titanium implant)and groupⅡ(plasma-coated titanium implant)did not differ in BIC%(83.51±8.5 vs 84.12±1.73;P=0.838).After 90 d,the BIC%was higher in group I(87.04±6.99 vs 81.24±7.62;P=0.049),compared to groupⅡ.The relative perimeter of the bone marrow after 45 d did not differ between groups and was 16.49%±8.58%for groupⅠ,and 15.88%±1.73%for groupⅡ.Futhermore,after 90 d,in groupⅠthe relative perimeter of bone marrow was 1.4 times smaller(12.96±6.99 vs 18.76±7.62;P=0.049)compared to the relative perimeter of bone marrow in groupⅡ.CONCLUSION The use of a highly porous titanium implant,manufactured with 3D printing,for acetabular components provides increased osseointegration compared to a plasma-coated titanium implant.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51373048)the National Key Research and Development Program of China(Grant Nos.U1604253 and 2016YFB0101602)
文摘To improve the strength of carbon fiber(CF) reinforced Polycaprolactam(PA6) composites, controlled amounts of carbon nanotubes(CNTs) were grafted onto the surface of CF to prepare the hybrid reinforcement(HR). We used HR to fabricate laminate and H-sample to test the interfacial bonding strength(IBS) of the composites by means of a novel process called three-dimensional printed molding(3 D-PM). By using the melt drop printing method, we measured the contact angles between PA6 and CF(without sizing) and between PA6 and HR. The IBS and the mechanical properties of the composites were obtained by the tensile test. The experimental result indicated that CF grafted by 0.25% weight fraction of CNT or more could develop a special microstructure similar to the micro-pits on the surface of CF, which improved the wettability of CF and PA6 due to the increased surface area and the roughness of CF. When the weight fraction of CNT reached 0.25%, the IBS increased by 41.8%, the tensile strength by 130%, and the interfacial shear strength(IFSS) by 238%. The interfacial dimple fracture was observed by Scanning Electron Microscope(SEM), which revealed that the composites were able to absorb more deforming energy before fracture. The modified surface microstructure of CF would prevent crack propagation at the interface and increase the mechanical properties of thermoplastic composites(TPCs).
基金This study was supported by the Education Department of Hainan Province(HnjgY2022-12)Hainan Provincial Natural Science Foundation of China(320CXTD437 and 2019RC189)+1 种基金the National Natural Science Foundation of China(32260127 and 31672303)to CYthe Hainan Provincial Innovative Research Program for Graduates(Qhyb2021-55)to XC.
文摘Living and/or non-living animal models are often used as stimuli to observe the behavioral responses of the target animals.In the past,parasites,predators,and harmless controls have been used to test host anti-parasitism defense behavior,and their taxidermy specimens have been widely used as a set of standard methods for the study of avian brood parasitism.In recent years,with the rapid development of 3D-printing technology,3D-printed bird models are expected to be applied as a standard method in the study of avian brood parasitism.To evaluate the use of 3D-printed models,this study tests the reaction of Oriental Reed Warbler(Acrocephalus orientalis)towards predators,parasites,or controls,and compares the reaction among different nest intruders and between taxidermy specimens and 3D-printed animal models.It was found that the Oriental Reed Warbler responded most aggressively to the parasite,followed by predator,and finally the control;the results were consistent between the reaction to taxidermy specimens and 3D-printed animal models,indicating that 3D-printed models could serve as a substitute for taxidermy specimens.We propose a series of advantages of using 3D-printed models and suggest them to be a standard method for widespread use in future studies of avian brood parasitism.
文摘In the current study poly(lactic acid)PLA composites with a 3 wt%and 5 wt%of nanofibrillated cellulose(NFC)were produced by 3D-printing method.An enzymatic pretreatment coupled with mechanical fibrillation in a twin screw extruder was used to produce high consistency NFC.Scanning electron microscopy(SEM)equipped with Fibermetric software,FASEP fiber length distribution analysis,Furrier transform infrared spectroscopy(FT-IR),thermogravimetric analysis(TGA),tensile tests,impact tests and differential scanning calorimetry were used to characterize NFC and PLA/NFC composites.The results of the fiber length and width measurements together with the results of the SEM analysis showed that enzymatic hydrolysis coupled with a twin screw extrusion could effectively reduce the diameter and length of cellulose fibers.The produced NFC consisted of microand nanosized fibers entangled in a characteristic 3D-network.Based on the FT-IR analysis,no new bonds were formed during the enzymatic hydrolysis or fibrillation process.The TGA analysis confirmed that produced NFC can be used in hightemperature extrusion processing without NFC degradation.During the PLA/NFC composites preparation the NFC agglomerates were formed,which negatively influenced PLA/NFC composites impact properties.The slightly improved tensile strength and elastic modulus were reported for all composites when compared to the neat PLA.The elongation at break was not affected by the NFC addition.No significant differences in thermal stability were detectable among composites nor in comparation with the neat PLA.However,the crystallinity degree of the composite containing 5 wt%NFC was increased in respect to the neat PLA.
基金Supported by the National Natural Science Foundation of China,No.81771949 and No.81471808the Project of Medical Key Specialty of Shanghai Municipality,No.ZK2015A22the Science and Technology Commission of Shanghai Municipality,No.18411968600
文摘AIM To evaluate a 3 D-printed coplanar template for iodine-125 seed implantation therapy in patients with pancreatic cancer. METHODS A retrospective analysis of our database was performed, and a total of 25 patients with pancreatic cancer who underwent iodine-125 seed implantation between January 2014 and November 2017 were analyzed. Of these, 12 implantations were assisted by a 3 D-printed coplanar template(group A), and 13 implantations performed freehand were selected as a control group(group B). A 3 D coplanar template was designed and printed according to a preoperative CT scan and treatment planning system. The iodine-125 seeds were then implanted using the template as a guide. Dosimetric verification was performed after implantation. Pre-and postoperative D90, V100, and V150 were calculated. The success rate of iodine-125 seed implantation, dosimetric parameters, and complications were analyzed and compared between the two groups.RESULTS Iodine-125 seed implantation was successfully performed in both groups. In group A, the median pre-and postoperative D90 values were 155.32 ± 8.05 Gy and 154.82 ± 16.43 Gy, respectively; the difference between these values was minimal and not statistically significant(P > 0.05). Postoperative V100 and V150 were 91.05% ± 4.06% and 64.54% ± 13.40%, respectively, which met the treatment requirement. A better dosimetric parameter was observed in group A than in group B, and the difference was statistically significant(V100: 91.05% ± 4.06% vs 72.91% ± 13.78%, P < 0.05). No major procedure-related complications were observed in either group. For group A, mild hemorrhage was observed in 1 patient with a peritoneal local hematoma due to mesenteric vein damage from the iodine-125 seed implantation needle. The hematoma resolved spontaneously without treatment. Postoperative blood amylase levels remained within the normal range for all patients.CONCLUSION A 3 D-printed coplanar template appears to be a safe and effective iodine-125 seed implantation guidance tool to improve implantation accuracy and optimize dosimetric distribution.
基金Supported by the National Natural Science Foundation of China,No.81571881
文摘Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such as "fistula patch" and vacuumassisted closure therapy have been applied to prevent contamination of open abdominal wounds by intestinal fistula drainage. However, failures are encountered due to high-output fistula and anatomical complexity. Here, we report 3 D-printed patient-personalized fistula stent for ECF treatment based on 3 D reconstruction of the fistula image. Subsequent follow-up demonstrated that this stent was well-implanted and effective to reduce the volume of enteric fistula effluent.
基金financially supported by the National Key R@D Program of China (2016YFB0100100, 2016YFA0200200)the National Natural Science Foundation of China (51872283,22075279, 21805273, 22005297, 22005298)+7 种基金the Liao Ning Revitalization Talents Program (XLYC1807153)the Central Government of Liaoning Province Guides The Funds for Local Science and Technology Development (2021JH6/10500112)the Dalian Innovation Support Plan for High Level Talents (2019RT09)the Dalian National Laboratory For Clean Energy (DNL),CASDNL Cooperation Fund,CAS (DNL201912, DNL201915, DNL202016, DNL202019)DICP (DICP ZZBS201708, DICP ZZBS201802, DICP I2020032)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy (YLU-DNL Fund 2021002)the China Postdoctoral Science Foundation (2019 M661141, 2020 M680995)。
文摘With the rapid development of integrated and miniaturized electronics,the planar energy storage devices with high capacitance and energy density are in enormous demand.Hence,the advanced manufacture and fast fabrication of microscale planar energy units are of great significance.Herein,we develop aqueous planar micro-supercapacitors(MSCs) with ultrahigh areal capacitance and energy density via an efficient all-3 D-printing strategy,which can directly extrude the active material ink and gel electrolyte onto the substrate to prepare electrochemical energy storage devices.Both the printed active carbon/exfoliated graphene(AC/EG) electrode ink and electrolyte gel are highly processable with outstanding conductivity(~97 S cm^(-1) of electrode;-34.8 mS cm^(-1) of electrolyte),thus benefiting the corresponding shaping and electrochemical performances.Furthermore,the 3 D-printed symmetric MSCs can be operated stably at a high voltage up to 2.0 V in water-in-salt gel electrolyte,displaying ultrahigh areal capacitance of2381 mF cm^(-2) and exceptional energy density of 331 μWh cm^(-2),superior to previous printed micro energy units.In addition,we can further tailor the integrated 3 D-printed MSCs in parallel and series with various voltage and current outputs,enabling metal-free interconnection.Therefore,our all-3 D-printed MSCs place a great potential in developing high-power micro-electronics fabrication and integration.
基金supported by initiatory financial support from Huazhong University of Science and Technology(HUST)the Monash University Postgraduate Publications Award。
文摘Three-dimensional(3D)-printed magnetic soft architectures have attracted extensive attention and research from the engineering and material fields.The force-driven shape deformation of such architectures causes a change in the magnetic field distribution,indicating the capability to convert mechanical energy to electricity.Herein,we fabricate a flexible superhydrophobic and magnetic device by integrating two kinds of 3D printing approaches.The 3D-printed magnetic device(3DMD)exhibits a long-term stable mechanoelectrical conversion capacity under consecutive water droplet dripping.The output current of the 3DMD is higher than that of records in the existing literature.Combined with Maxwell numerical simulation,the mechanoelectrical conversion mechanism of the 3DMD is investigated,further guiding regulation of the diverse parameters.Moreover,three 3DMDs are integrated to light up a commercial light-emitting diode(LED)by a stream of collected rainwater.Such a combined design incorporating energy conversion is believed to promisingly motive advances in the 3D printing field.
基金supported by the National Science Fund for Distinguished Young Scholars(52025034)National Natural Science Foundation of China(21975204)Innovation Team of Shaanxi Sanqin Scholars。
文摘Combining 3D printing with precursor-derived ceramic for fabricating electromagnetic(EM) wave-absorbing metamaterials has attracted great attention. This study presents a novel ultraviolet-curable polysiloxane precursor for digital light processing(DLP) 3D printing to fabricate ceramic parts with complex geometry, no cracks and linear shrinkage. Guiding with the principles of impedance matching, attenuation, and effective-medium theory, we design a crosshelix-array metamaterial model based on the complex permittivity constant of precursor-derived ceramics. The corresponding ceramic metamaterials can be successfully prepared by DLP printing and subsequent pyrolysis process, achieving a low reflection coefficient and a wide effective absorption bandwidth in the X-band even under high temperature. This is a general method that can be extended to other bands, which can be realized by merely adjusting the unit structure of meta-materials. This strategy provides a novel and effective avenue to achieve “target-design-fabricating” ceramic metamaterials, and it exposes the downstream applications of highly efficient and broad EM wave-absorbing materials and structures with great potential applications.