Biodegradable suture anchors based on Mg-Nd-Zn-Zr alloy were developed for ligament-to-bone fixation in rotator cuff surgeries. The Mg alloy anchors were designed with structural features of narrow ...tooth and wide tooth, and simulated through finite element analysis (FEA). Meanwhile, the corrosion behaviors of the Mg alloy anchors were studied by immersion test and the mechanical properties were investigated by measuring the maximum torque and pull-out force. The simulation result showed that the wide-tooth anchor exhibited more a uniform stress distribution and lower shear stress in the torsion process, suggesting a satisfactory torsional resistance of this structure. Meanwhile, the wide-tooth anchor exhibited a lower Von-Mises stress after applying the same pull-out force in the simulation, indicating a higher resistance to pull-out failure of the anchor. The result of the immersion test indicated that the wide-tooth anchor exhibited a slightly slower corrosion rate in Hank’s solution after 14-day immersion, which was beneficial to enhance the structural and mechanical stability of the biodegradable suture anchor. Furthermore, the results of the mechanical properties test demonstrated that the wide-tooth anchor showed superior performance with higher maximum torques and axial pull-out forces before and after corrosion. More importantly, the axial pull-out force and maximum torque for the wide-tooth anchor decreased by 5.86% and 8.64% after corrosion, which were significantly less than those for the narrow-tooth anchor. Therefore, the wide-tooth suture anchor with lower corrosion rate, higher mechanical properties and structural stability is a promising candidate for ligament-bone fixation in the repair of rotator cuff injuries.
•Three-dimensional electrochemical process for environmental applications was reviewed.•The conception, advantages, reactor and mechanisms of 3D electrode system were presented.•The anode/cathode ...materials, particle electrode and catalysts utilized were summarized.•Its applications for wastewater treatment and adsorbents regeneration were demonstrated.•Main processes parameters were discussed and possible outlook was suggested.
Three-dimensional (3D) electrochemical process has been recognized as an effective method for wastewater treatment. In comparison to two-dimensional (2D) electrochemical process, the introduction of particle electrodes brings about higher specific surface area and shorter distance of mass transfer, which renders it more effective and promising for environmental applications. This paper presents a comprehensive review on the development and application of this process. The conception, advantages and basic mechanisms of 3D system is presented. Different kinds of electrode materials utilized in 3D reactor are systematically summarized, including anode and cathode materials, particle electrode materials and their catalysts. The structures of 3D reactor as well as the effect of important operating parameters are discussed, such as cell voltage, treatment time and pH values. Their applications in various wastewaters treatment and adsorbents regeneration are thoroughly reviewed. Finally the outlook of the process for future research is suggested.
•Chemically modified graphite felt was prepared using ethanol and hydrazine hydrate as reagents.•Carbon nanoparticles with functional groups were deposited on the surface after modification.•The ...electrochemical activity for ORR and H2O2 generation on the modified electrode was improved.•The cathode modification effictively improved the EF performance for pollutant degradation.
A simple method with low-cost chemical reagents ethanol and hydrazine hydrate was used to modify graphite felt as the cathode for electro-Fenton (EF) application, using p-nitrophenol (p-Np) as the model pollutant. Characterized by scanning electron microscope, contact angle, Raman spectrum and X-ray photoelectron spectroscopy, the morphology and surface physicochemical properties after modification were observed considerably changed. After modification, some nanoparticles and oxygen and nitrogen-containing functional groups appeared on the cathode surface, which greatly improved the surface hydrophilic property and the electrocatalytic activity for oxygen reduction reaction. The effects led to the hydrogen peroxide accumulation on the modified cathode markedly increased to 175.8mgL−1, while that on the unmodified one was only 67.5mgL−1. p-Np of initial 50mgL−1 could be completely removed by EF using the modified cathode, and the mineralization ratio reached 51.4%, more than 2 times of the pristine one. After 10 cycles, the mineralization ratio of the modified cathode was still above 45%, suggesting that the modification method can provide an effective approach to improve EF performance, and thus benefits to promote its environmental applications.
•Hydrazine hydrate was firstly used to modify graphite felt for H2O2 production.•The modified cathodes exhibited higher activities for oxygen reduction.•The optimum concentration of hydrazine hydrate ...for chemical modification was 10%.•The effect of cathodic potential, pH and O2 flow rate were investigated.•The modified cathode had better performance in p-Np degradation by electro-Fenton.
A simple chemical method using hydrazine hydrate as the main reagent was firstly used to modify graphite felt as cathode for efficient electro-Fenton process. The influences of the different concentration of hydrazine hydrate were comparatively studied on the yield and current efficiency of H2O2 production, confirming that the modified cathode had much higher electrocatalytic activity. The optimum concentration of the hydrazine hydrate was 10%, and the yield of H2O2 was as 2.6 times as that without modification under the same conditions. The cyclic voltammetry analysis indicated that the modified cathodes exhibited stronger current responses and more negative hydrogen evolution potentials than the unmodified one. The operational parameters such as cathodic potential, pH and O2 flow rate were optimized for the efficient H2O2 electrogeneration. The maximum accumulation of H2O2, up to 247.2mg/L, was obtained at −0.75V (vs. SCE) and O2 flow rate of 0.4L/min. The influence of pH on the yield of H2O2 was slight, but it was obvious on current efficiency. The modified cathode was confirmed to be more efficient in degradation of p-nitrophenol by electro-Fenton process at both acidic and neutral pH, indicating the positive effect of chemical modification onto the performance.
In this paper, we incorporate loss preference into an M/M/1 queueing with a threshold disclosure policy and analyze its impact on the customers’ queueing strategies and the queueing system’s idle ...stationary probability. In the queueing system, customers are strategic and divided into two groups: the informed and the uninformed. Informed customers are assumed to be fully rational, whereas uninformed customers are assumed to have loss preference. Uninformed customers with loss preference are categorized into two types according to their asymmetry perceptions, which anchor on the difference between gain and loss: loss neutrality and loss aversion. We firstly determine customers’ equilibrium decisions, and then derive the idle stationary probability at equilibrium. We find that loss preference reduces the customers’ joining probability, and results in a higher idle stationary probability. Furthermore, we find that for the uninformed customers with stronger loss aversion, the system manager should lower the threshold of disclosure to maintain a stable demand of uninformed customers. In addition, in the case of mixed-strategy at equilibrium, with the increase of the threshold of disclosure, the idle stationary probability increases for an underloaded queue. However, for an overloaded queue, the idle stationary probability decreases with increasing the threshold of disclosure.
•A novel Fe doped PbO2 electrode was prepared based on Ti/TiO2 nanotube arrays.•It has high OEP and excellent performance for p-nitrophenol degradation.•The effect of Fe doping on activity was ...investigated, and 0.02M Fe was the optimal.•After Fe doping, the p-NP degradation rate increased 4.3 times.•It is promising for treating wastewater containing biorefractory organic pollutants.
A novel Fe doped PbO2 electrode with a high oxygen evolution potential (OEP) and excellent electrochemical oxidation performance was prepared based on Ti/TiO2 nanotube arrays (TNTs) for p-nitrophenol (p-NP) degradation. Characterized by scanning electron microscope (SEM), linear sweep voltammetry (LSV) and chronoamporometric experiments, the effect of Fe doping amount on the electrode activity was investigated. Fe doping on PbO2 electrode improved the electrode morphology, OEP, step current and thus the degradation of p-NP. The optimal Fe doped concentration was 0.02M, and the electrode prepared under this condition possessed the highest OEP of 2.7V and p-NP degradation performance. After 90min treatment, the p-NP degradation efficiency reached 100% with similar energy consumption, and the reaction rate constant increased about 4.3 times compared with that of the unmodified one. This Fe doped Ti/TNTs/PbO2 anode has a more promising application potential in treatment of wastewater containing biorefractory organic pollutants.
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► The instead of Ti substrate with TiO2-NTs greatly improved phenol electrocatalytic degradation. ► Pore diameter and length of TiO2-NTs are crucial to the pollutant degradation ...efficiency. ► TiO2-NTs architecture affects on the electrode morphology and oxygen evolution potential. ► TiO2-NTs/SnO2-Sb with 85nm pore diameter and 5μm length TiO2-NTs performed the best.
There are growing interests in the TiO2 nanotubes (TiO2-NTs) based Sb-doped SnO2 anode (TiO2-NTs/SnO2-Sb) for organic pollutants degradation due to its high oxygen evolution potential and enhanced degradation performance. However, whether and how the TiO2-NTs substrate architecture of the electrodes affects the electrocatalytic capability for organic pollutant degradation has not been reported yet. This work addressed this issue, investigating the effect of the pore diameter and length of TiO2-NTs on the electrocatalytic capability of TiO2-NTs/SnO2-Sb electrode, which was fabricated by Sb-doped SnO2 coating electrodeposition on different TiO2-NTs architecture substrates by successfully adjusting the Ti substrate anodization time and voltage. The characterizations of morphology, crystal structures and composition as well as the electrochemical characteristics were comparably studied. It confirmed the modification of TiO2-NTs substrate greatly improved the electrocatalytic degradation of organic pollutant, using phenol as the target contaminant. The pore diameter and length of TiO2-NTs substrates of the TiO2-NTs/SnO2-Sb electrode were verified to be crucial to the pollutant degradation efficiency, and the one with TiO2-NTs of 85nm pore diameter and 5μm length performed the best.
An implantable electrode based on bioresorbable Mg-Nd-Zn-Zr alloy was developed for next-generation radiofrequency (RF) tissue welding application, aiming to reduce thermal damage and enhance ...anastomotic strength. The Mg alloy electrode was designed with different structural features of cylindrical surface (CS) and continuous long ring (LR) in the welding area, and the electrothermal simulations were studied by finite element analysis (FEA). Meanwhile, the temperature variation during tissue welding was monitored and the anastomotic strength of welded tissue was assessed by measuring the avulsion force and burst pressure. FEA results showed that the mean temperature in the welding area and the proportion of necrotic tissue were significantly reduced when applying an alternating current of 110 V for 10 s to the LR electrode. In the experiment of tissue welding ex vivo, the maximum and mean temperatures of tissues welded by the LR electrode were also significantly reduced and the anastomotic strength of welded tissue could be obviously improved. Overall, an ideal welding temperature and anastomotic strength which meet the clinical requirement can be obtained after applying the LR electrode, suggesting that Mg-Nd-Zn-Zr alloy with optimal structure design shows great potential to develop implantable electrode for next-generation RF tissue welding application.
For decades, radiofrequency (RF)-induced tissue fusion has garnered great attention due to its potential to replace sutures and staples for anastomosis of tissue reconstruction. However, the ...complexities of achieving high bonding strength and reducing excessive thermal damage present substantial limitations of existing fusion devices.
This study proposed a discrete linkage-type electrode to carry out
RF-induced intestinal anastomosis experiments. The anastomotic strength was examined by burst pressure and shear strength test. The degree of thermal damage was monitored through an infrared thermal imager. And the anastomotic stoma fused by the electrode was further investigated through histopathological and ultrastructural observation.
The burst pressure and shear strength of anastomotic tissue can reach 62.2 ± 3.08 mmHg and 8.73 ± 1.11N, respectively, when the pressure, power and duration are 995 kPa, 160 W and 13 s, and the thermal damage can be controlled within limits. Histopathological and ultrastructural observation indicate that an intact and fully fused stomas with collagenic crosslink can be formed.
The discrete linkage-type electrode presents favorable efficiency and security in RF-induced tissue fusion, and these results are informative to the design of electrosurgical medical devices with controllable pressure and energy delivery.
A series of lead dioxide electrodes developed on titania nanotube arrays with different matrix were fabricated by electrodeposition. Before the deposition of PbO
2
, the matrix of this anode was ...electrochemically reduced in (NH
4
)
2
SO
4
solution and/or pre-deposited with certain amounts of copper. To gain insight into these pretreatments, the PbO
2
electrodes were characterized by SEM, LSV, and XRD, and their electrocatalytic activities for pollutant degradation were compared using
p
-nitrophenol (
p
-NP) as a model. It was confirmed that the electrochemical reduction with (NH
4
)
2
SO
4
resulted in the partial conversion of TiO
2
into Ti
4
O
7
and Ti
5
O
9
, which increased the conductivity of PbO
2
anode, but decreased its electrochemical activity, while the Ti/TNTs*-Cu/PbO
2
electrode with both pretreatments possessed the highest oxygen evolution overpotential of 2.5 V (vs. SCE) and low substrate resistance. After a 180-min treatment on this electrode, the removal efficiency of
p
-NP reached 82.5 % and the COD removal achieved 42.5 % with the energy consumption of 9.45 kWh m
−3
, demonstrating the best performance among these electrodes with different matrices. Therefore, this titania nanotube array-based PbO
2
electrode has a promising application in the industrial wastewater treatment.
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