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In order to solve the corrosion problem of grounding materials in highly corrosive red soil environments, conductive concrete was proposed as a new type of grounding material. The corrosion resistance of conductive concrete was tested and compared to select a suitable preparation scheme with excellent corrosion resistance. A series of conductive concrete samples were made using different conductive materials such as graphite, stainless steel fiber (SSF), and ordinary silicate concrete. Common grounding metals include Q235 steel and galvanized steel, embedded in red soil, conventional concrete, and conductive concrete. The open circuit potential, dynamic potential polarization, and electrochemical impedance spectroscopy of these metals were measured and analyzed. The open-circuit potential of metal electrodes in red soil is lower than that in concrete, and the potential of specimens with conductive phase is higher than that of the ordinary concrete, show that the corrosion sensitivity of metals in conductive concrete is greatly reduced, the corrosion potential is the lowest and the corrosion current is the highest in red soil, the capacitance arc radius in red soil is very small, indicating poor corrosion resistance of grounding metals in a red soil environment. All these indexs indicate that using conductive concrete as grounding material can effectively slow down the corrosion of grounding materials in red soil. Compared with stainless steel based conductive concrete, graphite based conductive concrete provides better protection for the grounding metal wrapped around it. As the content of conductive phase materials increases, the corrosion tendency and corrosion rate of conductive concrete decrease. Compared with Q235 carbon steel, galvanized steel exhibits excellent corrosion resistance in conductive concrete. Therefore, it is recommended to use galvanized steel conductive concrete as the grounding material for power systems in red soil environments.

Welding fumes induce lung toxicity and are carcinogenic to humans but the molecular mechanisms have yet to be clarified. The aim of this study was to evaluate the toxicity of stainless and mild steel particles generated via gas–metal arc welding using primary human small airway epithelial cells (hSAEC) and ToxTracker reporter murine stem cells, which track activation of six cancer-related pathways. Metal content (Fe, Mn, Ni, Cr) of the particles was relatively homogenous across particle size. The particles were not cytotoxic in reporter stem cells but stainless steel particles activated the Nrf2-dependent oxidative stress pathway. In hSAEC, both particle types induced time- and dose-dependent cytotoxicity, and stainless steel particles also increased generation of reactive oxygen species. The cellular metal content was higher for hSAEC compared to the reporter stem cells exposed to the same nominal dose. This was, in part, related to differences in particle agglomeration/sedimentation in the different cell media. Overall, our study showed differences in cytotoxicity and activation of cancer-related pathways between stainless and mild steel welding particles. Moreover, our data emphasizes the need for careful assessment of the cellular dose when comparing studies using different in vitro models.

Background Restoring first permanent molars after endodontic treatment in children is challenging. Improved mechanical properties and adhesion of ceramic materials have led to the emergence of endocrown as a conservative and esthetic restorative option for endodontically treated molars in adults and offer dentists a restorative treatment for endodontically treated first permanent molars in children. The purpose of this study was clinical and radiographic evaluation of both endocrowns fabricated from 2 different materials and SSCs restoring endodontically treated first permenant molars in children over one year. Methods Thirty children were selected (18 girls and 12 boys) with an age range of 10–13 years old, with an endodontically treated first molar. Children were randomly divided into 3 groups: PMC group (restored with preformed SSCs), EMX group (restored with litium disilicate endocrown), and COP group (restored with indirect reinforced composite endocrown) ( n  = 10). Evaluation was done in terms of parent satisfaction, radiograph (base line and 12 months), the restoration survival after 12 months, plaque index (PI), and gingival index (GI) at base line, 6 months, and 12 months.The data were analyzed using the Kruskal-Wallis H-test, which was used to compare an ordinal variable, and Friedman’s test was used to compare an ordinal variable ( P  ≤.050). Results Parent satisfaction showed statistically significant differences between PMC (mean rank = 7.5) and both EMX and COP (mean rank = 19.5) ( P  <.001), but not between the EMX and COP groups ( P  = 1.00). At 6 and 12 months, the PMC group’s PI values were statistically significantly higher than those of the EMX and COP groups ( P  =.001 and P  <.001, respectively). The GI values of the EMX and COP groups did not change significantly through different intervals ( P  = 1.000 and P  =.135, respectively), whereas the GI values of the PMC group did ( P  =.050). At various intervals, it was found that there was no significant difference in the GI values between the three groups. Conclusions The survival rates of endorowns and SSCs were comparable. Compared to SSCs, endocrowns demonstrated a higher parental satisfaction, less plaque buildup, and improved gingival response. Trial registration The study protocol was retrospectively registered on Clinical Trials under No. (NCT06432049-29/05/2024).

The aim of this study was threefold. Firstly, it aimed to introduce and detail a novel method for chemically etching the bases of stainless-steel orthodontic brackets. Secondly, the study sought to investigate the structural alterations within the brackets' microstructure following chemical etching compared to those with sandblasted bases, using electron microscopy analysis. Lastly, the study aimed to evaluate and compare the long-term durability and survivability of orthodontic brackets with chemically etched bases those with sandblasted bases, both bonded using the conventional acid etch technique with Transbond XT adhesive, over an 18-month follow-up period. The study was a randomized clinical control trial with triple blinding and split-mouth study design and consisted of two groups. The brackets in the sandblasted group were prepared by sandblasting the intaglio surface of the base of the bracket with 50 µm SiO particles. Hydrofluoric acid was used to roughen the base in the acid-etched group. The bases of the brackets were viewed under an electron microscope to analyze the topographical changes. A total of 5,803 brackets (3,006 acid-etch, 2,797 sandblasted) in 310 patients were bonded, in a split-mouth design by the same operator. The patients were followed for 18 months. The failure rate of 2.59% and 2.7% was noted in an acid-etched and sandblasted group, respectively. There was a close approximation of curves in the Kaplan-Meier plot, and the survival distribution of the two groups in the log-rank (Mantel-Cox) test was insignificant; x2 = 0.062 ( value = 0.804). Acid etching if the bases of the brackets can be used as an alternative to sandblasting furthermore acid etching can be performed on the chair side.

Background Anterior open bite (AOB) malocclusion usually represents a complicated and advanced orthodontic problem. The skeletal variant of AOB used to be treated with a combined orthodontic and surgical approach, until the posterior segments’ intrusion has been validated as an alternative, effective and conservative treatment modality for such cases with comparable outcomes to the surgical approach. The objective of this two-arm parallel randomized clinical trial was to compare the effects of mini-screw supported maxillary versus bi-maxillary buccal segments’ intrusion on the amount of anterior open bite closure. Methods Twenty-two adult patients aged 17–25 years, with skeletal open bite and anterior dental separation of 3–8 mm were randomized to either the comparator (Maxillary Intrusion with Consolidation of mandibular buccal segments-MIC) or intervention (Bimaxillary buccal segments’ intrusion-BMI) groups. Miniscrew-assisted buccal segments’ intrusion was instituted using fixed appliances on rigid stainless steel archwires (19 × 25 stainless steel) via nickel-titanium coil springs in the maxilla and memory chains in the mandible. The intrusion force was 200 g per maxillary buccal segment in both groups, and it was 150 g for each mandibular posterior segment in the BMI group. Duration of intrusion was 6 months. Results Anterior open bite was significantly closed in both groups with means of 3.8 ± 0.84 (95% confidence interval [CI] 3.2–4.4) and 3.84 ± 1.47 mm (CI;2.8–4.9) for the MIC and BMI groups, respectively with no significant difference between them (p-value < 0.05). Maxillary posterior teeth experienced significant intrusion in both groups, with a mean of 2.89 ± 1.13 mm (CI;2.63–3.14) in the MIC group and 2.26 ± 1.62 mm (CI;1.89–2.62) in the BMI group. Statistically significant mandibular posterior teeth intrusion occurred in both groups with means of 0.86 ± 0.91 (CI;0.65–1.06) and 0.33 ± 0.84 mm (CI;0.14–0.52) in the BMI and MIC groups, respectively, with a statistically significant difference of 0.53 ± 0.14 (CI;0.25–0.8) mm. However, such difference was considered clinically insignificant. Conclusions Anterior open bite closure could be successfully achieved with maxillary buccal segments intrusion without the need for active intrusion of the mandibular posterior segments, as long as the latter are efficiently consolidated. Trial registration The trial was prospectively registered at clinicaltrials.gov with an identifier number of NCT04713280.

Objectives: To evaluate and compare the parental satisfaction among resin composite strip crown, preveneered stainless steel crown (PVSSC) and the newly introduced pre-fabricated primary zirconia crown for restoring maxillary primary incisors. Study design: A prospective clinical study on 39 children with carious or traumatized primary maxillary incisors. They were randomly and equally distributed in three groups and received one of the full-coronal restorations. Children were recalled to evaluate and compare parental satisfaction about performance of crowns after one year through a questionnaire. Results: Parents were satisfied with all three tooth colored full-coronal restoration techniques. A significant relationship was found between colour of PVSSC (p=0.003) and durability of resin strip crowns (p=0.009) with the overall parental satisfaction levels. Parents who gave poor ratings in these two variables however rated their overall acceptance levels as being satisfied. Conclusion: Parental overall satisfaction was highest for zirconia primary crowns followed by resin composite strip crowns and lowest satisfaction was reported for pre-veneered SSCs. Parents were least satisfied with durability of resin composite strip crowns and colour of pre-veneered stainless steel crowns. However, this did not affect their overall satisfaction with these crowns.

A method of producing superstrong yet ductile steels using cheaper and lighter alloying elements is described, based on minimization of the lattice misfit to achieve a maximal dispersion of nanoprecipitates, leading to ultimate precipitation strengthening. Extreme precipitation makes superstrong steel Ultrastrong and yet ductile steels are important materials for the automotive and energy industries, among others. A key subgroup is the maraging steels, martensitic steels that have been aged by extended heat treatment. They acquire their strength from semi-coherent intermetallic precipitates. In this paper, maraging steels are described in which the expensive cobalt and titanium alloying elements are entirely replaced with lightweight and inexpensive aluminium. The resulting precipitates were produced in the steel at high density and with minimal lattice mismatch strain, leading to an impressive combination of very high strength (up to 2.2 gigapascals) and good ductility (about 8.2 per cent). The materials are characterized using a suite of high-resolution techniques, including atom probe tomography, HAADF STEM and synchrotron XRD. Next-generation high-performance structural materials are required for lightweight design strategies and advanced energy applications. Maraging steels, combining a martensite matrix with nanoprecipitates, are a class of high-strength materials with the potential for matching these demands 1 , 2 , 3 . Their outstanding strength originates from semi-coherent precipitates 4 , 5 , which unavoidably exhibit a heterogeneous distribution that creates large coherency strains, which in turn may promote crack initiation under load 6 , 7 , 8 . Here we report a counterintuitive strategy for the design of ultrastrong steel alloys by high-density nanoprecipitation with minimal lattice misfit. We found that these highly dispersed, fully coherent precipitates (that is, the crystal lattice of the precipitates is almost the same as that of the surrounding matrix), showing very low lattice misfit with the matrix and high anti-phase boundary energy, strengthen alloys without sacrificing ductility. Such low lattice misfit (0.03 ± 0.04 per cent) decreases the nucleation barrier for precipitation, thus enabling and stabilizing nanoprecipitates with an extremely high number density (more than 10 24 per cubic metre) and small size (about 2.7 ± 0.2 nanometres). The minimized elastic misfit strain around the particles does not contribute much to the dislocation interaction, which is typically needed for strength increase. Instead, our strengthening mechanism exploits the chemical ordering effect that creates backstresses (the forces opposing deformation) when precipitates are cut by dislocations. We create a class of steels, strengthened by Ni(Al,Fe) precipitates, with a strength of up to 2.2 gigapascals and good ductility (about 8.2 per cent). The chemical composition of the precipitates enables a substantial reduction in cost compared to conventional maraging steels owing to the replacement of the essential but high-cost alloying elements cobalt and titanium with inexpensive and lightweight aluminium. Strengthening of this class of steel alloy is based on minimal lattice misfit to achieve maximal precipitate dispersion and high cutting stress (the stress required for dislocations to cut through coherent precipitates and thus produce plastic deformation), and we envisage that this lattice misfit design concept may be applied to many other metallic alloys.

The antagonism between strength and resistance to hydrogen embrittlement in metallic materials is an intrinsic obstacle to the design of lightweight yet reliable structural components operated in hydrogen-containing environments. Economical and scalable microstructural solutions to this challenge must be found. Here, we introduce a counterintuitive strategy to exploit the typically undesired chemical heterogeneity within the material’s microstructure that enables local enhancement of crack resistance and local hydrogen trapping. We use this approach in a manganese-containing high-strength steel and produce a high dispersion of manganese-rich zones within the microstructure. These solute-rich buffer regions allow for local micro-tuning of the phase stability, arresting hydrogen-induced microcracks and thus interrupting the percolation of hydrogen-assisted damage. This results in a superior hydrogen embrittlement resistance (better by a factor of two) without sacrificing the material’s strength and ductility. The strategy of exploiting chemical heterogeneities, rather than avoiding them, broadens the horizon for microstructure engineering via advanced thermomechanical processing. Typically undesired chemically heterogeneous microstructures are shown to enhance the resistance of high-strength steel against hydrogen embrittlement, with no loss in strength or ductility.

Background The aim of this clinical investigation was to compare the level of discomfort reported by patients during the removal of orthodontic metallic brackets performed with four different debonding instruments. Methods The sample examined in this split-mouth study comprised a total of 70 patients (840 teeth). Four different methods of bracket removal were used: lift-off debonding instrument (LODI), straight cutter plier (SC), how plier (HP), and bracket removal plier (BRP). Prior to debonding with all experimental methods, the archwire was removed. Before appliance removal, each patient was instructed about the study objectives. It was explained that at the end of debonding in each quadrant, it would be necessary to assess the discomfort of the procedure using a visual analog scale (VAS). This scale was composed of a millimeter ruler scoring from 0 to 10, in which 0 = a lot of pain, 5 = moderate pain, and 10 = painless. The level of significance was predetermined at 5 % ( p  = 0.05), and the data were analyzed using the BioEstat 5.0 software (BioEstat, Belém, Brazil). Results The pain scores with SC were significantly higher than in all other methods. There were no significant differences between HP and BRP pain scores, and the LODI group showed the lowest pain scores. Statistically, significant differences were observed in the ARI between the four debonding methods. Limitations The biggest limitation of this study is that each tooth was not assessed individually. Conclusions Patients reported lower levels of pain and discomfort when metallic brackets were removed with the LODI. The use of a straight cutter plier caused the highest pain and discomfort scores during debonding.

In recent years, the anti-corrosive properties of natural extracts as environmentally friendly inhibitors have gained considerable interest. This study evaluates the potential of ( L.) essential oil ( ), collected from Salé, Morocco, as a corrosion inhibitor for mild steel in 1 M HCl medium. The protection performance of was assessed using various electrochemical techniques, including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), as well as the weight loss method. The influence of concentration and temperature on the inhibition performance were investigated. demonstrated pronounced inhibitory benefits via increasing the corrosion resistance of mild steel in the corrosive HCl solution, thus reducing the corrosion rate to 0.11 mg cm h and increasing the inhibition efficiency to 87.1% at an inhibitor concentration of 500 ppm. PDP confirmed that the inhibitor works as a mixed-type inhibitor with cathodic supremacy. EIS revealed that the charge transfer mechanism is the main controlling factor for the corrosion process. The thermodynamic parameters suggested a key role of physisorption in inhibition, following the Langmuir isotherm. Importantly, SEM and EDX analyses suggested the formation of a protective layer of the extract onto the steel surface, which shields the surface from corrosive species. This is owed to the functional group-rich phytochemicals of . Therefore, the development of bio-based corrosion inhibitors is not only a step towards more eco-friendly industrial practices, but also meets the growing demand for sustainable materials in a world with constrained resources.