Axial compression behavior of carbon fiber reinforced polymer confined partially encased recycled concrete columns.

Partially encased concrete (PEC) has better mechanical properties as a structure where steel and concrete work together. Due to the increasing amount of construction waste, recycled aggregate concrete (RAC) is being considered by more people. However, although RAC has more points, the performance is inferior to natural aggregate concrete (NAC). To narrow or address this gap, lightweight, high-strength and corrosion-resistant CFRP can be used, also protecting the steel flange of the PEC structure. Therefore, carbon fiber reinforced polymer (CFRP) confined partially encased recycled coarse aggregate concrete columns were studied in this paper. With respect to different slenderness ratios, recycled coarse aggregate(RCA) replacement ratios, and number of CFRP layers, the performance of the proposed CFRP restrained columns are reported. The RCA replacement ratio is analyzed to be limited negative impact on the bearing capacity, generally within 6%. As for the slenderness ratio, the bearing capacity increased with it. However, wrapping CFRP significantly increased the bearing capacity. Considering the arch factor, a simple formula for calculating the ultimate strength of CFRP-confined partially encased RAC columns is developed based on EC4 and GB50017-2017. By comparison with the experimental values, the error is within 10%.

Dental implant and abutment in PEEK: stress assessment in single crown retainers on anterior region.

OBJECTIVE: Stress distribution assessment by finite elements analysis in poly(etheretherketone) (PEEK) implant and abutment as retainers of single crowns in the anterior region. MATERIALS AND METHODS: Five 3D models were created, varying implant/abutment manufacturing materials: titanium (Ti), zirconia (Zr), pure PEEK (PEEKp), carbon fiber-reinforced PEEK (PEEKc), glass fiber-reinforced PEEK (PEEKg). A 50 N load was applied 30o off-axis at the incisal edge of the upper central incisor. The Von Mises stress (σvM) was evaluated on abutment, implant/screw, and minimum principal stress (σmin) and maximum shear stress (τmax) for cortical and cancellous bone. RESULTS: The abutment σvM lowest stress was observed in PEEKp group, being 70% lower than Ti and 74% than Zr. On the implant, PEEKp reduced 68% compared to Ti and a 71% to Zr. In the abutment screws, an increase of at least 33% was found in PEEKc compared to Ti, and of at least 81% to Zr. For cortical bone, the highest τmax values were in the PEEKp group, and a slight increase in stress was observed compared to all PEEK groups with Ti and Zr. For σmin, the highest stress was found in the PEEKc. Stress increased at least 7% in cancellous bone for all PEEK groups. CONCLUSION: Abutments and implants made by PEEKc concentrate less σvM stress, transmitting greater stress to the cortical and medullary bone. CLINICAL RELEVANCE: The best stress distribution in PEEKc components may contribute to decreased stress shielding; in vitro and in vivo research is recommended to investigate this.

Self-powered biosensing sutures for real-time wound monitoring.

Effective wound management has the potential to reduce both the duration and cost of wound healing. However, traditional methods often rely on direct observation or complex and expensive biological testing to monitor and evaluate the invasive damage caused by wound healing, which can be time-consuming. Biosensors offer the advantage of precise and real-time monitoring, but existing devices are not suitable for integration with sensitive wound tissue due to their external dimensions. Here, we have designed a self-powered biosensing suture (SPBS) based on biofuel cells to accurately monitor glucose concentration at the wound site and promote wound healing. The anode of the SPBS consists of carbon nanotubes-modified carbon fibers, tetrathiafulvalene (TTF), and glucose oxidase (GOx), while the cathode is composed of Ag2O and carbon nanotubes modified nanotubes modified carbon fibers. It was observed that SPBS exhibited excellent physical and chemical stability in vitro. Regardless of different bending degrees or pH values, the maximum power density of SPBS remained above 92%, which is conducive to long-term dynamic evaluation. Furthermore, the voltage generated by SPBS reflects blood glucose concentration, and measurements at wound sites are consistent with those obtained using a commercially available blood glucose meter. SPBS achieves the healing effect of traditional medical sutures after complete healing within 14 days. It offers valuable insights for intelligent devices dedicated to real-time wound monitoring.

Biotribological properties of 3D printed high-oriented short carbon fiber reinforced polymer composites for artificial joints.

Short carbon fiber (SCF) reinforced polymer composites are expected to possess outstanding biotribological and mechanical properties in certain direction, while the non-oriented SCF weakens its reinforcing effect in the matrix. In this work, high-oriented SCF was achieved during nozzle extrusion, and then SCF reinforced polyether-ether-ketone (PEEK) composites were fabricated by fused deposition modeling (FDM). The concrete orientation process of SCF was theoretically simulated, and significant shear stress difference was generated at both ends of SCF. As a result, the SCF was distributed in the matrix in a hierarchical structure, containing surface layer I, II and core layer. Moreover, the SCF was oriented highly along the printing direction and demonstrated a more competitive orientation distribution compared to other studies. The SCF/PEEK composites showed a considerable improvement in wear resistance by 44 % due to self-lubricating and load-bearing capability of SCF. Besides, it demonstrated enhancements in Brinell hardness, compressive and impact strength by 48.52 %, 16.42 % and 53.64 %, respectively. In addition, SCF/PEEK composites also showed good cytocompatibility. The findings gained herein are useful for developing the high-oriented SCF reinforced polymer composites with superior biotribological and mechanical properties for artificial joints.

Foot offloading associated with carbon fiber orthosis use: A pilot study.

BACKGROUND: Traumatic lower limb injuries can result in chronic pain. Orthotic interventions are a leading conservative approach to reduce pain, manage loading, and protect the foot. Robust carbon fiber custom dynamic orthoses (CDOs) designed for military service members have been shown to reduce foot loading. However, the effect of carbon fiber orthosis design, including designs widely used in the civilian sector, on foot loading is unknown. RESEARCH QUESTION: Determine if carbon fiber orthoses alter foot loading during gait. METHODS: Loadsol insoles were used to measure peak forces and force impulse acting on the forefoot, midfoot, hindfoot, and total foot. Nine healthy, able-bodied individuals participated. Force impulse was quantified as cumulative loading throughout stance phase. Participants walked without an orthosis and with three carbon fiber orthoses of differing designs: a Firm stiffness CDO, a Moderate stiffness CDO, and a medial and lateral strut orthosis (MLSO). RESULTS: There were significant main effects of orthosis condition on peak forefoot forces as well as forefoot and hindfoot force impulse. Peak forefoot forces were significantly lower in the Moderate and Firm CDOs compared to no orthosis and MLSO. Compared to walking without an orthosis, forefoot force impulse was significantly lower and hindfoot force impulse was significantly greater in all carbon fiber orthoses. Additionally, hindfoot force impulse in the Firm CDO was significantly higher than in the MLSO and Moderate CDO. SIGNIFICANCE: The three carbon fiber orthosis designs differed regarding foot loading, with more robust orthoses providing greater forefoot offloading. Orthosis-related changes in forefoot loading suggest that carbon fiber orthoses could reduce loading-associated pain during gait. However, increased hindfoot force impulse suggests caution should be used when considering carbon fiber orthoses for individuals at risk of skin breakdown with repetitive loading.

Optimized Fabrication of Carbon-Fiber Microbiosensors for Codetection of Glucose and Dopamine in Brain Tissue.

Dopamine (DA) signaling is critically important in striatal function, and this metabolically demanding process is fueled largely by glucose. However, DA and glucose are typically studied independently and, as such, the precise relationship between DA release and glucose availability remains unclear. Fast-scan cyclic voltammetry (FSCV) is commonly coupled with carbon-fiber microelectrodes to study DA transients. These microelectrodes can be modified with glucose oxidase (GOx) to generate microbiosensors capable of simultaneously quantifying real-time and physiologically relevant fluctuations of glucose, a nonelectrochemically active substrate, and DA, which is readily oxidized and reduced at the electrode surface. A chitosan hydrogel can be electrodeposited to entrap the oxidase enzyme on the sensor surface for stable, sensitive, and selective codetection of glucose and DA using FSCV. This strategy can also be used to entrap lactate oxidase on the carbon-fiber surface for codetection of lactate and DA. However, these custom probes are individually fabricated by hand, and performance is variable. This study characterizes the physical nature of the hydrogel and its effects on the acquired electrochemical data in the detection of glucose (2.6 mM) and DA (1 µM). The results demonstrate that the electrodeposition of the hydrogel membrane is improved using a linear potential sweep rather than a direct step to the target potential. Electrochemical impedance spectroscopy data relate information on the physical nature of the electrode/solution interface to the electrochemical performance of bare and enzyme-modified carbon-fiber microelectrodes. The electrodeposition waveform and scan rate were characterized for optimal membrane formation and performance. Finally, codetection of both DA/glucose and DA/lactate was demonstrated in intact rat striatum using probes fabricated according to the optimized protocol. Overall, this work improves the reliable fabrication of carbon-fiber microbiosensors for codetection of DA and important energetic substrates that are locally delivered to the recording site to meet metabolic demand.

Simultaneous Dopamine and Serotonin Monitoring in Freely Moving Crayfish Using a Wireless Electrochemical Sensing System.

Dopamine (DA) and serotonin (5-HT) are neurotransmitters that regulate a wide range of physiological and behavioral processes. Monitoring of both neurotransmitters with real-time analysis offers important insight into the mechanisms that shape animal behavior. However, bioelectronic tools to simultaneously monitor DA and 5-HT interactive dynamics in freely moving animals are underdeveloped. This is mainly due to the limited sensor sensitivity with miniaturized electronics. Here, we present a semi-implantable electrochemical device achieved by integrating a multi-surface-modified carbon fiber microelectrode with a miniaturized potentiostat module to detect DA and 5-HT in vivo with high sensitivity and selectivity. Specifically, carbon fiber microelectrodes were modified through electrochemical treatment and surface coatings to improve sensitivity, selectivity, and antifouling properties. A customized, lightweight potentiostat module was developed for untethered electrochemical measurements. Integrated with the microelectrode, the microsystem is compact (2.8 × 2.3 × 2.1 cm) to minimize its impacts on animal behavior and achieved simultaneous detection of DA and 5-HT with sensitivities of 48.4 and 133.0 nA/µM, respectively, within submicromolar ranges. The system was attached to the crayfish dorsal carapace, allowing electrode implantation into the heart of a crayfish to monitor DA and 5-HT dynamics, followed by drug injections. The semi-implantable biosensor system displayed a significant increase in oxidation peak currents after DA and 5-HT injections. The device successfully demonstrated the application for in vivo simultaneous monitoring of DA and 5-HT in the hemolymph (i.e., blood) of freely behaving crayfish underwater, yielding a valuable experimental tool to expand our understanding of the comodulation of DA and 5-HT.

Controlling the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers via the design of condensed structures.

Obtaining lignin-based graphite-like microcrystallites at a relatively low carbonization temperature is still very challenging. In this work, we report a new method based on condensed structures, for regulating graphite-like microcrystalline structures via the incorporation of 4,4'-diphenylmethane diisocyanate (MDI) into the main structure of lignin. The effects of MDI on the thermal properties of lignin and the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers were extensively studied and investigated. The incorporation of MDI decreased the thermal stability of lignin, increased the carbon yield and enhanced the formation of graphite-like microcrystallites, which are beneficial for reducing energy consumption during the preparation of lignin-based carbon fibers. The modified lignin-based ultrafine carbon fibers (M-LCFs) demonstrated satisfactory electrochemical performance, including high specific capacitance, low charge transfer resistance, and good cycle performance. The M-LCFs-3/2 electrode had a specific capacitance of 241.3 F g-1 at a current density of 0.5 A g-1, and a residual ratio of 90.2 % after 2000 charge and discharge cycles. This study provides a new approach to control the graphite-like microcrystalline structure and electrochemical performance while also optimizing the temperature.

Cytotoxicity of novel hybrid composite materials for making bone fracture plates.

Bone fracture plates are usually made from steel or titanium, which are much stiffer than cortical bone. This may cause bone 'stress shielding' (i.e. bone resorption leading to plate loosening) and delayed fracture healing (i.e. fracture motion is less than needed to stimulate callus formation at the fracture). Thus, the authors previously designed, fabricated, and mechanically tested novel 'hybrid' composites made from inorganic and organic materials as potential bone fracture plates that are more flexible to reduce these negative effects. This is the first study to measure the cytotoxicity of these composites via the survival of rat cells. Cubes of carbon fiber/flax fiber/epoxy and glass fiber/flax fiber/epoxy had better cell survival vs. Kevlar fiber/flax fiber/epoxy (57% and 58% vs. 50%). Layers and powders made of carbon fiber/epoxy and glass fiber/epoxy had higher cell survival than Kevlar fiber/epoxy (96%-100% and 100% vs. 39%-90%). The presence of flax fibers usually decreased cell survival. Thus, carbon and glass fiber composites (with or without flax fibers), but not Kevlar fiber composites (with or without flax fibers), may potentially be used for bone fracture plates.

Understanding the different effects of fouling mechanisms on working and reference electrodes in fast-scan cyclic voltammetry for neurotransmitter detection.

Fast-scan cyclic voltammetry (FSCV) is a widely used technique for detecting neurotransmitters. However, electrode fouling can negatively impact its accuracy and sensitivity. Fouling refers to the accumulation of unwanted materials on the electrode surface, which can alter its electrochemical properties and reduce its sensitivity and selectivity. Fouling mechanisms can be broad and may include biofouling, the accumulation of biomolecules on the electrode surface, and chemical fouling, the deposition of unwanted chemical species. Despite individual studies discussing fouling effects on either the working electrode or the reference electrode, no comprehensive study has been conducted to compare the overall fouling effects on both electrodes in the context of FSCV. Here, we examined the effects of biofouling and chemical fouling on the carbon fiber micro-electrode (CFME) as the working electrode and the Ag/AgCl reference electrode with FSCV. Both fouling mechanisms significantly decreased the sensitivity and caused peak voltage shifts in the FSCV signal with the CFME, but not with the Ag/AgCl reference electrode. Interestingly, previous studies have reported peak voltage shifts in FSCV signals due to the fouling of Ag/AgCl electrodes after implantation in the brain. We noticed in a previous study that energy-dispersive spectroscopy (EDS) spectra showed increased sulfide ion concentration after implantation. We hypothesized that sulfide ions may be responsible for the peak voltage shift. To test this hypothesis, we added sulfide ions to the buffer solution, which decreased the open circuit potential of the Ag/AgCl electrode and caused a peak voltage shift in the FSCV voltammograms. Also, EDS analysis showed that sulfide ion concentration increased on the surface of the Ag/AgCl electrodes after 3 weeks of chronic implantation, necessitating consideration of sulfide ions as the fouling agent for the reference electrodes. Overall, our study provides important insights into the mechanisms of electrode fouling and its impact on FSCV measurements. These findings could inform the design of FSCV experiments, with the development of new strategies for improving the accuracy and reliability of FSCV measurements in vivo.

Inflammatory tissue response in human soft tissue is caused by a higher particle load near carbon fiber-reinforced PEEK compared to titanium plates.

Titanium as the leading implant material in locked plating is challenged by polymers such as carbon fiber-reinforced polyetheretherketone (CFR-PEEK), which became the focus of interest of researchers and manufacturers in recent years. However, data on human tissue response to these new implant materials are rare. Osteosynthesis plates and peri­implant soft tissue samples of 16 healed proximal humerus fractures were examined (n = 8 CFR-PEEK, n = 8 titanium). Soft tissue was analyzed by immunohistochemistry and µCT. The entrapped foreign bodies were further examined for their material composition by FTIR. To gain insight into their origin and formation mechanism, explanted and new plates were evaluated by SEM, EDX, profilometry and HR-CT. In the peri­implant soft tissue of the CFR-PEEK plates, an inflammatory tissue reaction was detected. Tissues contained foreign bodies, which could be identified as tantalum wires, carbon fiber fragments and PEEK particles. Titanium particles were also found in the peri­implant soft tissue of the titanium plates but showed a less intense surrounding tissue inflammation in immunohistochemistry. The surface of explanted CFR-PEEK plates was rougher and showed exposed and broken carbon fibers as well as protruding and deformed tantalum wires, especially in used screw holes, whereas scratches were identified on the titanium plate surfaces. Particles were present in the peri­implant soft tissue neighboring both implant materials and could be clearly assigned to the plate material. Particles from both plate materials caused detectable tissue inflammation, with more inflammatory cells found in soft tissue over CFR-PEEK plates than over titanium plates. STATEMENT OF SIGNIFICANCE: Osteosynthesis plates are ubiquitously used in various medical specialties for the reconstruction of bone fractures and defects and are therefore indispensable for trauma surgeons, ENT specialists and many others. The leading implant material are metals such as titanium, but recently implants made of polymers such as carbon fiber-reinforced polyetheretherketone (CFR-PEEK) have become increasingly popular. However, little is known about human tissue reaction and particle generation related to these new implant types. To clarify this question, 16 osteosynthesis plates (n = 8 titanium and n = 8 CFR-PEEK) and the overlying soft tissue were analyzed regarding particle occurrence and tissue inflammation. Tissue inflammation is clinically relevant for the development of scar tissue, which is discussed to cause movement restrictions and thus contributes significantly to patient outcome.

In situ detection of dopamine in single living cells by molecularly imprinted polymer-functionalized nanoelectrodes.

In situ detection of dopamine (DA) at single-cell level is critical for exploring neurotransmitter-related biological processes and diseases. However, the low content of DA and a variety of distractors with similar oxidation potentials as DA in cells brought great challenges. Here, a sensitive and specific electrochemical nanosensor was proposed for in situ detection of DA in single living cells based on nanodiamond (ND) and molecularly imprinted polymer (MIP)-functionalized carbon fiber nanoelectrode (ND/MIP/CFNE). Due to its excellent electrocatalytic property, ND was modified to the surface of CFNE based on amide bonding. Compared with bare CFNE, ND-modified CFNE can enhance oxidation currents of DA by about 4-fold, improving signal-to-noise ratio and detection sensitivity. MIP was further electropolymerized on the surface of nanoelectrodes to achieve specific capture and recognition of DA, which could avoid the interference of complex matrix and analogs in cells. Taking advantage of the precise positioning capability of a single-cell analyzer and micromanipulator, ND/MIP/CFNE could be precisely inserted into different locations of single cells and monitor oxidation signal of DA. The concentration of DA in the cytoplasm of single pheochromocytoma (PC12) cell was measured to be about 0.4 µM, providing a sensitive and powerful method for single-cell detection. Furthermore, the nanoelectrodes can monitor the fluctuation of intracellular DA under drug stimulation, providing new ideas and methods for new drug development and efficacy evaluation.

Carbon fiber-sampling combined flame ionization mass spectrometry for direct analysis of drugs in oral fluid.

Drug-impaired driving poses a significant risk of collisions and other hazardous accidents, emphasizing the urgent need for simple and rapid roadside detection methods. Oral fluid, as an easily collectible and non-invasive test material, has gained widespread use in detecting drug-impaired driving. In this study, we have devised a method for direct sampling using a carbon fiber bundle combined with flame ionization mass spectrometry. The essence of this method lies in the synergy between the adsorption properties of carbon fiber and the plasma characteristics of the flame. Leveraging the strong adsorption capabilities of the carbon fiber bundle allows for the use of a minimal sample size (<100 µL) during sampling, presenting a distinct advantage in the roadside inspection and sampling process. Throughout the flame ionization process, proteins and salts within the oral fluid matrix adhere well to the carbon fiber bundle, while small molecule targets can be efficiently desorbed and react with charged species in the flame, leading to ionization. The results demonstrate the successful development of carbon fiber-sampling combined flame ionization mass spectrometry, capable of qualitative and quantitative analysis of drugs in oral fluid without the need for sample pre-treatment. Its quantitative capabilities are sufficient for real sample detection, providing an effective analytical method for the roadside detection of drugs in oral fluids.

Comparative evaluation on wear resistance of metal sleeve, sleeve-free resin, and reinforced sleeve-free resin implant guide: An in vitro study.

BACKGROUND: In-office three-dimensional (3D) printers and metal sleeveless surgical guides are becoming a major trend recently. However, metal sleeve-free designs are reported to be more prone to distortion which might lead to variation in the inner diameter of the drill hole and cause deviation and inaccuracy in the placement of the implant. Carbon fiber nanoparticles are reported to improve the properties of 3D printing resin material in industrial application. AIM: The purpose of the study is to evaluate and compare the wear resistance of 3D-printed implant guides with metal sleeve, sleeve-free, and reinforced sleeve-free resin to the guide drill. MATERIALS AND METHODS: A total of 66 samples with 22 samples in each group. Three groups including 3D-printed surgical guide with metal sleeve (Group A), without metal sleeve (Group B), an carbon fiber reinforced without metal sleeve (Group C) were included in the study. All samples were evaluated before sequential drilling and after sequential drilling using Vision Measuring Machine. The data were tabulated and statistically evaluated. RESULTS: The data obtained were statistically analyzed with one-way analysis of variance and posthoc test. The data obtained for wear observed in the samples showed that the wear was highest in Group B with a mean of 0.5036 ± 0.1118 and the least was observed in Group A with a mean of 0.0228 ± 0.0154 and Group C was almost similar to Group A with mean of 0.0710 ± 0.0381. The results showed there was a significant difference between Group B with Group A and C, respectively (P < 0.05). The results showed that there was no significant difference regarding the wear observed between Groups A and C (P > 0.05). CONCLUSION: The wear observed in the guide with a metal sleeve and carbon fiber reinforced without a metal sleeve was almost similar. The carbon fiber-reinforced guide showed better tolerance to guide drill equivalent to metal sleeve. Thus, carbon fiber nanoparticles reinforced in 3D printing resin have shown improved strength and can be used as a good replacement for a metal sleeve for an accurate placement of the implant.

Evaluation of computed tomography artefacts of carbon-fiber and titanium implants in patients with spinal oligometastatic disease undergoing stereotactic ablative radiotherapy.

This study evaluated artefacts on computed tomography (CT) images using Hounsfield units (HU) in patients with spinal oligometastatic disease who received carbon-fiber (CF; n = 11) or titanium (n = 11) spine implants and underwent stereotactic ablative radiotherapy (SABR). Pre- and postoperative HU were measured at the vertebral body, pedicle, and spinal cord at three different levels: the lower instrumented vertebra, the level of metastatic spinal cord compression, and an uninvolved level. Areas measured at each level were delicately matched pre- and postoperatively. Significant differences in HU were observed at the vertebral body, the pedicle, and the spinal cord at the lowest instrumented vertebra level for both CF and titanium (average increase 1.54-fold and 5.11-fold respectively). At the metastatic spinal cord compression level, a trend towards a higher HU-increase was observed in titanium compared with CF treated patients (average increase 2.51-fold and 1.43-fold respectively). The relatively high postoperative HU-increase after insertion of titanium implants indicated CT artefacts, while the relatively low HU-increase of CF implants was not associated with artefacts. Less CT artefacts could facilitate an easier contouring phase in radiotherapy planning. In addition, we propose a CT artefact grading system based on postoperative HU-increase. This system could serve as a valuable tool in future research to assess if less CT artefacts lead to time savings during radiotherapy treatment planning and, potentially, to better tumoricidal effects and less adverse effects if particle therapy would be administered.

PDA-Fe3O4 decorated carbon felt anode enhancing electrochemical performance of microbial fuel cells: Effect of electrode materials on electroactive biofilm.

Anode modification is an effective strategy for enhancing the electrochemical performance of microbial fuel cell (MFC). However, the impacts of the modified materials on anode biofilm development during MFC operation have been less studied. We prepared a novel PDA-Fe3O4-CF composite anode by coating original carbon felt anode (CF) with polydopamine (PDA) and Fe3O4 nanoparticles. The composite anode material was characterized by excellent hydrophilicity and electrical conductivity, and the anodic biofilm exhibited fast start-up, higher biomass, and more uniform biofilm layer after MFC operation. The MFC reactor assembled with the composite anode achieved a maximum power density of 608 mW m-2 and an output voltage of 586 mV, which were 316.4% and 72.4% higher than the MFC with the original CF anode, respectively. Microbial community analysis indicated that the modified anode biofilm had a higher relative abundance of exoelectrogen species in comparison to the unmodified anode. The PICRUSt data revealed that the anodic materials may affect the bioelectrochemical performance of the biofilm by influencing the expression levels of key enzyme genes involved in biofilm extracellular polymer (EPS) secretion and extracellular electron transfer (EET). The growth of the anodic biofilm would exert positive or negative influences on the efficiency of electricity production and electron transfer of the MFCs at different operating stages. This work expands the knowledge of the role that anodic materials play in the development and electrochemical performance of anodic biofilm in MFCs.

Cotton-derived three-dimensional carbon fiber aerogel with hollow nanocapsules and ultrahigh adsorption efficiency in dynamic sewage treatment system.

An ultralight 3D carbon fiber aerogel with good flexibility is developed via soaking cotton in water and then calcinating at a high temperature. This cotton-derived carbon material is constituted by amorphous carbon and retains slight oxygen-containing groups. Besides, a lot of hollow carbon nanocapsules are yielded on the inside surface, resulting in abundant micropores and mesopores. Systemic investigations explore the molecular transformation from cotton to carbon fiber, and the formation of carbon nanocapsules. In the adsorption process for methyl orange (MO), this carbon fiber aerogel exhibits both a rapid adsorption rate and the ultrahigh adsorbability of 862.9 mg/g, outclassing most of carbon materials reported. Therefore, a dynamic sewage treatment system is built and consecutively removes hydrosoluble pollution for a long-term running time. For the cotton-derived carbon fiber aerogel, the good mechanical flexibility, excellent adsorption property, and high stability jointly provide a vast application prospect in future industrial wastewater remediation.

Preparation of PANI-SA/CF anode to enhance the remediation and power generation capabilities of plant microbial fuel cells for chromium contaminated soil.

Plant microbial fuel cells (PMFCs) has important value for soil remediation and power generation. To improve the performance of PMFCs, a PMFC experimental system was established based on potted scindapsus aureus. Polyaniline (PANI) and sodium alginate (SA) were used as modifiers to prepare PANI-SA modified carbon felt anode. The soil remediation ability and electricity generation ability of PMFCs with four different anodes were compared and analyzed. The experimental results show that the steady-state voltage, the removal rate of hexavalent chromium, and the total chromium removal rate of PMFC using PANI-SA modified anode were 5.25 mV, 98%, and 90%, respectively, which are 253%, 10.4%, and 10% higher than those of PMFCs using unmodified carbon felt anode. PMFC is effective and feasible for removing soil chromium pollution and achieving efficient soil remediation, while modifying anodes with PANI-SA can further improve the soil remediation and electricity generation capabilities of PMFC.

Investigation on three-dimensional printed prosthetics leg sockets coated with different reinforcement materials: analysis on mechanical strength and microstructural.

Previous research has primarily focused on pre-processing parameters such as design, material selection, and printing techniques to improve the strength of 3D-printed prosthetic leg sockets. However, these methods fail to address the major challenges that arise post-printing, namely failures at the distal end of the socket and susceptibility to shear failure. Addressing this gap, the study aims to enhance the mechanical properties of 3D-printed prosthetic leg sockets through post-processing techniques. Fifteen PLA + prosthetic leg sockets are fabricated and reinforced with four materials: carbon fiber, carbon-Kevlar fiber, fiberglass, and cement. Mechanical and microstructural properties of the sockets are evaluated through axial compression testing and scanning electron microscopy (SEM). Results highlight superior attributes of cement-reinforced sockets, exhibiting significantly higher yield strength (up to 89.57% more than counterparts) and higher Young's modulus (up to 76.15% greater). SEM reveals correlations between microstructural properties and socket strength. These findings deepen the comprehension of 3D-printed prosthetic leg socket post-processing, presenting optimization prospects. Future research can focus on refining fabrication techniques, exploring alternative reinforcement materials, and investigating the long-term durability and functionality of post-processed 3D-printed prosthetic leg sockets.

BMSCs-driven graphite oxide-grafted-carbon fibers reinforced polyetheretherketone composites as functional implants: in vivo biosafety and osteogenesis.

Mesenchymal stem cells (MSCs) are increasingly becoming a potential treatment approach for bone injuries due to the multi-lineage differentiation potential, ability to recognize damaged tissue sites and secrete bioactive factors that can enhance tissue repair. The aim of this work was to improve osteogenesis of carbon fibers reinforced polyetheretherketone (CF/PEEK) implants through bone marrow mesenchymal stem cells (BMSCs)-based therapy. Moreover, bioactive graphene oxide (GO) was introduced into CF/PEEK by grafting GO onto CF to boost the osteogenic efficiency of BMSCs. Subsequently, CF/PEEK was implanted into the symmetrical skull defect models of SD rats. Then in vivo biosafety and osteogenesis were evaluated. The results indicated that surface wettability of CF/PEEK was effectively improved by GO, which was beneficial for the adhesion of BMSCs. The pathological tissue sections stained with H&E showed no significant pathological change in the main organs including heart, liver, spleen, lung and kidney, which indicated no acute systemic toxicity. Furthermore, bone mineralization deposition rate of CF/PEEK containing GO was 2.2 times that of pure CF/PEEK. The X-ray test showed that the surface of CF/PEEK containing GO was obviously covered by more newly formed bone tissue than pure CF/PEEK after 8 weeks of implantation. This work demonstrated that GO effectively enhanced surface bioactivity of CF/PEEK and assisted BMSCs in accelerating differentiation into bone tissue, providing a feasible strategy for improving osteogenesis of PEEK and CF/PEEK.