A New Class of Proton Conductors with Dramatically Enhanced Stability and High Conductivity for Reversible Solid Oxide Cells.

Reversible solid oxide cells based on proton conductors (P-ReSOCs) have potential to be the most efficient and low-cost option for large-scale energy storage and power generation, holding promise as an enabler for the implementation of intermittent renewable energy technologies and the widespread utilization of hydrogen. Here, the rational design of a new class of hexavalent Mo/W-doped proton-conducting electrolytes with excellent durability while maintaining high conductivity is reported. Specifically, BaMo(W)0.03 Ce0.71 Yb0.26 O3-δ exhibits dramatically enhanced chemical stability against high concentrations of steam and carbon dioxide than the state-of-the-art electrolyte materials while retaining similar ionic conductivity. In addition, P-ReSOCs based on BaW0.03 Ce0.71 Yb0.26 O3-δ demonstrate high peak power densities of 1.54, 1.03, 0.72, and 0.48 W cm-2 at 650, 600, 550, and 500 °C, respectively, in the fuel cell mode. During steam electrolysis, a high current density of 2.28 A cm-2 is achieved at a cell voltage of 1.3 V at 600 °C, and the electrolysis cell can operate stably with no noticeable degradation when exposed to high humidity of 30% H2 O at -0.5 A cm-2 and 600 °C for over 300 h. Overall, this work demonstrates the promise of donor doping for obtaining proton conductors with both high conductivity and chemical stability for P-ReSOCs.

Tuning Proton Insertion Chemistry for Sustainable Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (ZIBs) have emerged as an alternative to lithium-ion batteries due to their affordability and high level of safety. However, their commercialization is hindered by the low mass loading and irreversible structural changes of the cathode materials during cycling. Here, a disordered phase of a manganese nickel cobalt dioxide cathode material derived from wastewater via a coprecipitation process is reported. When used as the cathode for aqueous ZIBs , the developed electrode delivers 98% capacity retention at a current density of 0.1 A g-1 and 72% capacity retention at 1 A g-1 while maintaining high mass loading (15 mg cm-2 ). The high performance is attributed to the structural stability of the Co and Ni codoped phase; the dopants effectively suppress Jahn-Teller distortion of the manganese dioxide during cycling, as revealed by operando X-ray absorption spectroscopy. Also, it is found that the Co and Ni co-doped phase effectively inhibits the dissolution of Mn2+ , resulting in enhanced durability without capacity decay at first 20 cycles. Further, it is found that the performance of the electrode is sensitive to the ratio of Ni to Co, providing important insight into rational design of more efficient cathode materials for low-cost, sustainable, rechargeable aqueous ZIBs.

Patella Denervation With Circumferential Electrocautery in Primary Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The aim of this study was to investigate the clinical effectiveness of patella rim electrocautery "denervation" versus no denervation in patients undergoing total knee arthroplasty (TKA). METHODS: We conducted a single-center, double-blind randomized controlled trial. Patients aged 40 years or older, due to undergo a TKA who did not have patella resurfacing (usual care) were randomized with or without circumferential patella electrocautery. This was undertaken according to a randomly generated sequence of treatment allocation that was placed into numbered, sealed opaque envelopes. Participants were blinded to treatment allocation. There was no crossover. The primary outcome was Oxford Knee Score at 1 year postoperatively. Secondary outcomes were Bartlett Patella Score, Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short Form Survey. Linear regression analyses were performed with adjustments by age, sex, and baseline (preoperative) scores. There were 142 participants recruited, of which 49 (35%) were allocated to the denervation intervention. Recruitment was stopped early when interim statistical analyses confirmed adequate numbers in both groups despite an imbalance in early treatment allocation rates due to the randomization method. The mean patient age was 71 years (range, 50 to 85) and 51% (n = 74) were women. RESULTS: No difference in Oxford Knee Score was detected at 1 year (mean difference [MD] 1.87; 95% confidence interval [CI] -1.28 to 5.03). No difference was detected in Bartlett Patella Score (MD 0.490; 95% CI -1.61 to 2.59) or 12-Item Short Form Survey (MD 0.196; 95% CI -2.54 to 2.93). A statistically significant difference in WOMAC was detected, but at a level less than the minimal clinically important difference for WOMAC (MD 4.79; 95% CI 1.05 to 8.52). CONCLUSION: No clinically relevant benefit was detected from patella rim electrocautery in patients undergoing TKA who did not have patella resurfacing (including no benefit in terms of anterior knee pain). This treatment is therefore not recommended for clinical practice. LEVEL OF EVIDENCE: Level 1.

Periprosthetic joint infection of the hip.

Aims: The number of revision arthroplasties being performed in the elderly is expected to rise, including revision for infection. The primary aim of this study was to measure the treatment success rate for octogenarians undergoing revision total hip arthroplasty (THA) for periprosthetic joint infection (PJI) compared to a younger cohort. Secondary outcomes were complications and mortality. Methods: Patients undergoing one- or two-stage revision of a primary THA for PJI between January 2008 and January 2021 were identified. Age, sex, BMI, American Society of Anesthesiologists grade, Charlson Comorbidity Index (CCI), McPherson systemic host grade, and causative organism were collated for all patients. PJI was classified as 'confirmed', 'likely', or 'unlikely' according to the 2021 European Bone and Joint Infection Society criteria. Primary outcomes were complications, reoperation, re-revision, and successful treatment of PJI. A total of 37 patients aged 80 years or older and 120 patients aged under 80 years were identified. The octogenarian group had a significantly lower BMI and significantly higher CCI and McPherson systemic host grades compared to the younger cohort. Results: The majority of patients were planned to undergo two-stage revision, although a significantly higher proportion of the octogenarians did not proceed with the second stage (38.7% (n = 12) vs 14.8% (n = 16); p = 0.003). Although there was some evidence of a lower complication rate in the younger cohort, this did not reach statistical significance (p = 0.065). No significant difference in reoperation (21.6% (n = 8) vs 25.0% (n = 30); p = 0.675) or re-revision rate (8.1% (n = 3) vs 16.7% (n = 20); p = 0.288) was identified between the groups. There was no difference in treatment success between groups (octogenarian 89.2% (n = 33) vs control 82.5% (n = 99); p = 0.444). Conclusion: When compared to a younger cohort, octogenarians did not show a significant difference in complication, re-revision, or treatment success rates. However, given they are less likely to be eligible to proceed with second stage revision, consideration should be given to either single-stage revision or use of an articulated spacer to maximize functional outcomes.

Durable and High-Performance Thin-Film BHYb-Coated BZCYYb Bilayer Electrolytes for Proton-Conducting Reversible Solid Oxide Cells.

Proton-conducting reversible solid oxide cells are a promising technology for efficient conversion between electricity and chemical fuels, making them well-suited for the deployment of renewable energies and load leveling. However, state-of-the-art proton conductors are limited by an inherent trade-off between conductivity and stability. The bilayer electrolyte design bypasses this limitation by combining a highly conductive electrolyte backbone (e.g., BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb1711)) with a highly stable protection layer (e.g., BaHf0.8Yb0.2O3-δ (BHYb82)). Here, a BHYb82-BZCYYb1711 bilayer electrolyte is developed, which dramatically enhances the chemical stability while maintaining high electrochemical performance. The dense and epitaxial BHYb82 protection layer effectively protects the BZCYYb1711 from degradation in contaminating atmospheres such as high concentrations of steam and CO2. When exposed to CO2 (3% H2O), the bilayer cell degrades at a rate of 0.4 to 1.1%/1000 h, which is much lower than the unmodified cells at 5.1 to 7.0%. The optimized BHYb82 thin-film coating adds negligible resistance to the BZCYYb1711 electrolyte while providing a greatly enhanced chemical stability. Bilayer-based single cells demonstrated state-of-the-art electrochemical performance, with a high peak power density of 1.22 W cm-2 in the fuel cell mode and -1.86 A cm-2 at 1.3 V in the electrolysis mode at 600 °C, while demonstrating excellent long-term stability.

A Synergistic Three-Phase, Triple-Conducting Air Electrode for Reversible Proton-Conducting Solid Oxide Cells.

Reversible proton-conducting solid oxide cells (R-PSOCs) have the potential to be the most efficient and cost-effective electrochemical device for energy storage and conversion. A breakthrough in air electrode material development is vital to minimizing the energy loss and degradation of R-PSOCs. Here we report a class of triple-conducting air electrode materials by judiciously doping transition- and rare-earth metal ions into a proton-conducting electrolyte material, which demonstrate outstanding activity and durability for R-PSOC applications. The optimized composition Ba0.9Pr0.1Hf0.1Y0.1Co0.8O3-δ (BPHYC) consists of three phases, which have a synergistic effect on enhancing the performance, as revealed from electrochemical analysis and theoretical calculations. When applied to R-PSOCs operated at 600 °C, a peak power density of 1.37 W cm-2 is demonstrated in the fuel cell mode, and a current density of 2.40 A cm-2 is achieved at a cell voltage of 1.3 V in the water electrolysis mode under stable operation for hundreds of hours.

Elective hip arthroplasty rates and related complications in people with diabetes mellitus.

BACKGROUND AND AIMS: Diabetes mellitus (DM), poor glycaemic control and raised body mass index (BMI) have been associated with postoperative complications in arthroplasty, although the relative importance of these factors is unclear. We describe the prevalence of DM in elective hip arthroplasty in a UK centre, and evaluate the impact of these factors. METHODS: We analysed retrospective data for DM patients undergoing arthroplasty over a 6-year period and compared with non-diabetic matched controls (1 DM patient: 5 controls). DM was present in 5.7% of hip arthroplasty patients (82/1443). RESULTS: Postoperative complications occurred in 12.2% of DM patients versus 12.9% of controls (p = 1.000); surgical complications were present in 6.1% of those with DM and 2.4% of controls (p = 0.087), while medical complications occurred in 8.5% of DM patients versus 10.7% of controls (p = 0.692). Complications developed in 23.1% of DM patients with poor glycaemic control (HbA1c > 53 mmol/mol) versus 9.8% with good control (p = 0.169). In DM patients and controls combined, complications occurred in 16.3% of obese patients versus 10.0% of non-obese patients (p = 0.043). In the DM cohort, 13.7% of overweight patients had complications versus 0% with a normal or low BMI (p = 0.587). CONCLUSIONS: DM rates were lower than expected, and glycaemic control was good. Overall complication rates were unrelated to the presence of DM or to glycaemic control, although surgical complications were observed more frequently in those with DM and poor glycaemic control was uncommon within our cohort. Complications were more frequent in those with a higher BMI. Whether some patients with DM but without an increased risk of complications are currently being excluded from surgery requires exploration.

Cement-in-cement femoral component revision : a comparison of two different taper-slip designs with medium-term follow up.

AIMS: Cement-in-cement revision of the femoral component represents a widely practised technique for a variety of indications in revision total hip arthroplasty. In this study, we compare the clinical and radiological outcomes of two polished tapered femoral components. METHODS: From our prospectively collated database, we identified all patients undergoing cement-in-cement revision from January 2005 to January 2013 who had a minimum of two years' follow-up. All cases were performed by the senior author using either an Exeter short revision stem or the C-Stem AMT high offset No. 1 prosthesis. Patients were followed-up annually with clinical and radiological assessment. RESULTS: A total of 97 patients matched the inclusion criteria (50 Exeter and 47 C-Stem AMT components). There were no significant differences between the patient demographic data in either group. Mean follow-up was 9.7 years. A significant improvement in Oxford Hip Score (OHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 12-item Short-Form Survey (SF-12) scores was observed in both cohorts. Leg lengths were significantly shorter in the Exeter group, with a mean of -4 mm in this cohort compared with 0 mm in the C-Stem AMT group. One patient in the Exeter group had early evidence of radiological loosening. In total, 16 patients (15%) underwent further revision of the femoral component (seven in the C-Stem AMT group and nine in the Exeter group). No femoral components were revised for aseptic loosening. There were two cases of femoral component fracture in the Exeter group. CONCLUSION: Our series shows promising mid-term outcomes for the cement-in-cement revision technique using either the Exeter or C-Stem AMT components. These results demonstrate that cement-in-cement revision using a double or triple taper-slip design is a safe and reliable technique when used for the correct indications. Cite this article: Bone Joint J 2021;103-B(7):1215-1221.

High-Performance, Thermal Cycling Stable, Coking-Tolerant Solid Oxide Fuel Cells with Nanostructured Electrodes.

Solid oxide fuel cells (SOFCs) are a promising solution to a sustainable energy future. However, cell performance and stability remain a challenge. Durable, nanostructured electrodes fabricated via a simple, cost-effective method are an effective way to address these problems. In this work, both the nanostructured PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) cathode and Ni-Ce0.8Sm0.2O1.9 (SDC) anode are fabricated on a porous yttria-stabilized zirconia (YSZ) backbone via solution infiltration. Symmetrical cells with a configuration of PBSCF|YSZ|PBSCF show a low interfacial polarization resistance of 0.03 Ω cm2 with minimal degradation at 700 °C for 600 h. Ni-SDC|YSZ|PBSCF single cells exhibit a peak power density of 0.62 W cm-2 at 650 °C operated on H2 with good thermal cycling stability for 110 h. Single cells also show excellent coking tolerance with stable operation on CH4 for over 120 h. This work offers a promising pathway toward the development of high-performance and durable SOFCs to be powered by natural gas.