Search

Lower muscular weakness and gait disturbance are typical lumbar spinal stenosis (LSS) symptoms. Gait initiation and standing balance function are dependent on hip muscle groups, particularly gluteus medius (GMed). However, alterations to GMed in LSS patients have not been studied. Therefore, we evaluated the impact of LSS on GMed in this study.This study included 96 participants divided into the LSS and non-LSS groups. A total of 48 patients with LSS and unilateral buttock pain underwent T2-weighted magnetic resonance imaging (MRI) of GMed, and 48 age- and sex-matched controls formed the control group. Differences between the cross-sectional area (CSA) on both sides of GMed were compared between the two groups. Additionally, correlations among patient characteristics, clinical evaluation, and radiological measurement data with a decrease in the CSA of GMed were assessed in the LSS group.A significant difference was observed in the bilateral discrepancy of the GMed CSA between the LSS and non-LSS groups. For LSS patients with unilateral buttock pain, 81% had reduced CSA of GMed. Regression analysis of the revealed that buttock pain was an independent factor related to GMed atrophy.The degree of GMed atrophy is related to symptoms of LSS. Spine surgeons should be aware of the risk of GMed atrophy in LSS patients with unilateral buttock pain.

To simplify the treatment of radioactive wastewater and reduce the secondary pollution, in this work, mesoporous ZrO2/SBA-15 was synthesized and employed for the first time as both the adsorbents and crystalline matrices for efficient enrichment and in-situ immobilization of U in radioactive wastewater. In general, U was efficiently enriched by using the mesoporous ZrO2/SBA-15 and then immobilized into ZrSiO4 ceramics by the followed sintering process. The U-adsorbed ZrO2/SBA-15 was changed to stable ZrSiO4–U ceramics by sintering at 1250–1450 °C for 6 h. The results also provided the evidence that both U(Ⅳ) and (Ⅵ) were incorporated into the crystal structure of ZrSiO4 by replacing Zr(Ⅳ). Furthermore, all the obtained ZrSiO4–U ceramics exhibited good aqueous durability. Given the high adsorption capacity and good aqueous durability, it is expected that the ZrO2/SBA-15 is attractive for actual applications in treatment of U containing radioactive wastewater.

pH-responsible self-healing core-shell electrospun nanofibers encapsulating oleic acid (OA) and benzotriazole (BTA) corrosion inhibitors were synthesized and added into a coating material for the corrosion protection of carbon steels. The shell of electrospun nanofibers were poly(vinyl alcohol) (PVA), and the healing agents OA and BTA were used as core materials to reseal a damaged region. The average nanofiber diameters was 350 nm, and the surface is smooth, without any bead structure. OA plays a critical role on corrosion inhibitor in 3.5% alkaline sodium chloride solution and the maximum inhibition efficiency was 86.0% after 10 days immersion. BTA works in 3.5% acidic sodium chloride solution and the maximum inhibition efficiency was 83.4% after 5 days immersion. The anti-corrosion and self-healing capability of core-shell coating were evaluated through scanning electron microscopy, transmission electron microscopy, confocal laser fluorescence microscopy, Fourier transform infrared spectroscopy, electrochemical measurement technology, thermo gravimetric analysis, and material test system rack. Results showed that core-shell spinning fibers with corrosion inhibitors at different concentrations were prepared successfully. The core-shell fibers released the inhibitors to form an OA protective film and a BTA passivation film on the exposed metal surface. Electrochemical measurement monitored specifically the self-healing properties of the coating. These result potentially have important value for the design and research of self-healing materials in the future.

A shape-memory polyurethane (SMPU) was designed and used in the field of self-healing coating due to the capability to recover to its permanent shape in a predefined way. This technique could be modified by two different kinds of microcapsules to improve the localized corrosion resistance of healed coating by induction heating. For this purpose, the SMPU was synthesized by solvent polymerization using isophorone diisocyanate (IPDI) as hard segments and polycaprolactone (PCL) as soft segments. The results obtained from dynamic mechanical thermal analysis (DMTA) displayed a phase-separation structure, which is consistent with the results of 1H NMR characterization. The repeatable shape-memory measurements further demonstrated that the shape recovery of SMPU is above 75%. Appending some microcapsules embedding Alodine 5200 and a heat-generating agent into SMPU, adhesion of aluminum substrate with healed coatings could be greatly improved, as well as corrosion resistance. In addition, the heat released from the exothermic reaction between the heat-generating agent and oxygen are supplied to the shape-memory recovery of polyurethane. It was clear that the corrosion resistance evaluations (by electrochemical impedance spectroscopy and scanning Kelvin probe measurements) confirm that the modified shape memory polyurethane have comparable healing efficiencies (η = 77.3%) and excellent self-healing performances.

Corrosion behavior of two different low alloy steels (specimen 1, specimen 2) coupling to titanium (Ti) alloy was studied in simulative deep-sea environment with 500 m depths. Immersion tests revealed that the corrosion rate of specimen 1 was higher than that of specimen 2. The micro morphology showed all specimens of specimen 1 steel was susceptible to both intergranular and pitting corrosion. Electrochemical results imply that the galvanic current of specimen 1 was bigger than specimen 2, then decreased and stabilized at a small range after 15 h correspond. Finite element method was constructed to explain the development of the galvanic current density distribution with distance to the electrodes. The corrosion resistance of the alloy steels followed the order: specimen 2 > specimen 1 when coupling to Ti alloy.

Nano-silica hydrogel modified by 1, 2, 4-triazole used as anti-corrosion additive was prepared, and the self-healing property as well as the anti-corrosion performance of the unmodified and modified hydrogels coatings on Q235 steel surfaces were investigated. In comparison to the anti-corrosion properties of the unmodified hydrogel, the migration of the corrosive media to the modified hydrogel coatings was significantly improved due to the addition of the 1, 2, 4-triazole and the increased compactness degree of the film. Electrochemical impedance spectroscopy results indicated that several stages did appear during the self-healing process. Finally, the self-healing as well as the anti-corrosion mechanism of the modified hydrogels was discussed.

Development of high efficient adsorbents to capture iodine is of great significance for the active development of nuclear power. Herein, Bi0-SBA-15 was firstly synthesized and applied for capture of iodine gas. Bi0-SBA-15 materials were prepared by an improved impregnation reduction method. The benefit of this method was that the Bi0 nanoparticles with flocculent and spherical morphologies were loaded on the surface of SBA-15, which provide abundant active sites for iodine and improve the utilization rate of active sites, so as to attain a record high capture capacity (up to 925 mg/g within 60 min) and high stablitiy (91.2%) at 200 °C. The results demonstrated that the loading of Bi0 on the surface showed a significant impact on the structure of Bi0-SBA-15 and did greatly enhance the iodine capture. Furthermore, the high iodine capture capacity mainly derived from the chemical adsorption in the stable form of BiI3. The obtained Bi0-SBA-15 materials exhibited excellent aqueous and irradiation stability. Thus, the results indicated that the new and highly efficient Bi0-SBA-15 was a potential radioactive iodine gas capture material.

Zircon (ZrSiO4) ceramics were widely used in the field of nuclear waste immobilization because of their excellent properties. However, the SiO2/ZrSiO4 ceramics were usually obtained in the preparation of ZrSiO4. The actinides immobilization behavior of SiO2/ZrSiO4 ceramics is unclear. Herein, Nd-doped 0.2SiO2/Zr1-xNdxSiO4-x/2 (0≤x ​≤ ​0.1) ceramics were fabricated and the effects of Nd-doping and sintering temperature on their phase and microstructure evolution were investigated. The obtained ceramics were characterized by XRD, SEM, BSE and EDS. Results show that 0.2SiO2/Zr1-xNdxSiO4-x/2 ceramics with 0≤x ​

In this study, we present the novel self-healing magnetic microcapsule preparation of poly(urea-formaldehyde) embedded with benzotriazole (BTA) and magnetic multi-wall carbon nanotubes (MWCNTs) to accelerate the self-healing efficiency of the coating significantly. The BTA played a role of the corrosion inhibitor, while the magnetic MWCNTs served as a target for the formation process of self-healing magnetic gradient (SMG) coating. The magnetic microcapsules could be easily as well as rapidly migrated in the coating solution via an external magnetic field. The SMG coating not only shortened the migration route of the released BTA, but also accelerated quickly the formation of a passivation film, and the corrosion of the copper was hindered, after the coating was damaged mechanically. It was further demonstrated that initial self-healing efficiency of SMG coating was approximately 6.4 times more than that of self-healing coating without magnetism. The present work successfully demonstrated the accelerated self-healing activity of magnetic MWCNTs microcapsules in protecting copper surfaces. The outcomes might help to magnetize the material and guide future design of self-healing coating.

Steel bars in concrete structures can become severely corroded in chloride salt-containing environments, which can shorten the service life of the structure. Bidirectional electromigration rehabilitation (BIEM), a novel type of durability repair technology used on reinforced-concrete (RC) structures experiencing chloride corrosion, involves applying an electric field to discharge chloride ions from concrete and simultaneously applying a rust inhibitor to the steel surface. In this study, indoor experiments were performed to analyse the migration of chloride ions and the corrosion inhibitor in RC structures in the atmosphere and water-level-fluctuating areas. An electroosmotic device enhanced the efficiency of BIEM. The BIEM was particularly effective in wet–dry areas and inside the electroosmotic device. More than 90% of the chloride ions on the steel surface were removed within 15 mm of the electroosmotic device, and the chloride ion migration rate on the steel surface was 40%–60%. Scanning electron microscopy revealed that the surface of the steel bars was smooth after BIEM treatment, with no obvious pitting or corrosion products. The service life of concrete was calculated according to the prediction method of concrete. It can be expected that the concrete enters the early warning zone after 15 years and the rust zone after 30 years.

Fe-based heterogeneous Fenton-like catalysts has shown tremendous potential for wastewater treatment, but the investigation of adsorption, reduction and oxidation mechanism remains challenging. In this study, nanoscale zero-valent iron encapsulated in three-dimensional graphene network (3D-GN@nZVI) was synthesized and characterized as a heterogeneous Fenton-like catalyst via the activation of dissolved oxygen (DO) for adsorption and degradation of sulfadiazine (SDZ). 3D-GN@nZVI had the synergistic effect of catalytic reactivity for sulfadiazine removal, which was evaluated in view of the effects of operational factors. The role of adsorption, reduction and oxidation was determined; in 3D-GN@nZVI/DO system, sulfadiazine was removed mainly by the attack of hydroxyl radicals ( OH). The possible degradation pathway of sulfadiazine was inferred by identifying reactive oxidizing species and degradation intermediates. According to the X-ray photoelectron spectroscopy (XPS) analysis, Fourier Transform infrared spectroscopy (FTIR) analysis and density functional theory (DFT) calculations, the distribution and transfer of electrons on the surface of 3D-GN@nZVI were illustrated, and the adsorption and oxidation mechanisms of sulfadiazine through DO-driven and micro-electrolysis-enhanced heterogeneous Fenton-like reaction were proposed. The comprehensive mechanism was elucidated to provide new insights to advance the DO-driven Fenton-like process and to inspire the development of nZVI and relevant composites.

The Zanhuang domain in the hinterland of the North China Craton, consists of Archaean, Paleoproterozoic, Mesoproterozoic and Palaeozoic rocks, and was previously considered a Mesozoic metamorphic core complex. Our reappraisal of regional structural history and mineral 40 Ar/ 39 Ar geochronology shows that the domain was subjected to a number of deformation events and had a heterogeneous uplift-cooling history during the Paleoproterozoic. Four primary deformation events have been recognized in the domain. The first event reflects the earliest deformation in the region, however, only closed and rootless folds are preserved. D2 was dominated by WNW-ESE shortening and top-to-ESE thrusting in a collisional environment. D3 was a divergent extensional and ductile shearing event, driven by the post-collisional extensional collapse and exhumation of the thickened crust in the domain. D4 was characterized by localized ductile shearing with the development of three NNE-trending ductile shear zones. The 40 Ar/ 39 Ar plateau ages derived from the thermochronology analyses of the biotite concentrates from the metamorphic rocks are interpreted as cooling ages through biotite 40 Ar/ 39 Ar closure temperature (300 °C) and this allows us to constrain the timing of deformation events. In conjunction with the evidence from structural analyses and previous geochronological data, we conclude that 1870 and 1870–1826 Ma define the timing of D1 and D2 events, respectively, while 1826–1793 Ma represents the age of D3. The last event (D4) occurred at 1689–1633 Ma, as constrained by 40 Ar/ 39 Ar plateau ages of biotite concentrates from the mylonites within the ductile shear zones. These data, together with K-feldspar 40 Ar/ 39 Ar geochronology, allows us to depict the cooling history of the region during the Paleoproterozoic and Mesoproterozoic. It appears that the uplift-cooling rate varies temporally and spatially in the region.