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Corner-sharing oxides usually suffer from structural reconstruction during the bottleneck oxygen-evolution reaction (OER) in water electrolysis. Therefore, introducing dynamically stable active sites in an alternative structure is urgent but challenging. Here, 1D 5H-polytype Ba 5 Bi 0.25 Co 3.75 FeO 14- δ oxide with face-sharing motifs is identified as a highly active and stable candidate for alkaline OER. Benefiting from the stable face-sharing motifs with three couples of combined bonds, Ba 5 Bi 0.25 Co 3.75 FeO 14- δ can maintain its local structures even under high OER potentials as evidenced by fast operando spectroscopy, contributing to a negligible performance degradation over 110 h. Besides, the higher Co valence and smaller orbital bandgap in Ba 5 Bi 0.25 Co 3.75 FeO 14- δ endow it with a much better electron transport ability than its corner-sharing counterpart, leading to a distinctly reduced overpotential of 308 mV at 10 mA cm -2 in 0.1 m KOH. Further mechanism studies show that the short distance between lattice-oxygen sites in face-sharing Ba 5 Bi 0.25 Co 3.75 FeO 14- δ can accelerate the deprotonation step (*OOH + OH -  = *OO + H 2 O + e - ) via a steric inductive effect to promote lattice-oxygen participation. In this work, not only is a new 1D face-sharing oxide with impressive OER performance discovered, but also a rational design of dynamic stable and active sites for sustainable energy systems is inaugurated., (© 2021 Wiley-VCH GmbH.)

Tip-enhanced Raman spectroscopy (TERS) is a nano-optical approach to extract spatially resolved chemical information with nanometer precision. However, in the case of direct-illumination TERS, which is often employed in commercial TERS instruments, strong fluorescence or far-field Raman signals from the illuminated areas may be excited as a background. They may overwhelm the near-field TERS signal and dramatically decrease the near-field to far-field signal contrast of TERS spectra. It is still challenging for TERS to study the surface of fluorescent materials or a bulk sample that cannot be placed on an Au/Ag substrate. In this study, we developed an indirect-illumination TERS probe that allows a laser to be focused on a flat interface of a thin-film waveguide located far away from the region generating the TERS signal. Surface plasmon polaritons are generated stably on the waveguide and eventually accumulated at the tip apex, thereby producing a spatially and energetically confined hotspot to ensure stable and high-resolution TERS measurements with a low background. With this thin-film waveguide probe, TERS spectra with obvious contrast from a diamond plate can be acquired. Furthermore, the TERS technique based on this probe exhibits excellent TERS signal stability, a long lifetime, and good spatial resolution. This technique is expected to have commercial potential and enable further popularization and development of TERS technology as a powerful analytical method.

Ion leaching from pure-phase oxygen-evolving electrocatalysts generally exists, leading to the collapse and loss of catalyst crystalline matrix. Here, different from previous design methodologies of pure-phase perovskites, we introduce soluble BaCl 2 and SrCl 2 into perovskites through a self-assembly process aimed at simultaneously tuning dual cation/anion leaching effects and optimizing ion match in perovskites to protect the crystalline matrix. As a proof-of-concept, self-assembled hybrid Ba 0.35 Sr 0.65 Co 0.8 Fe 0.2 O 3-δ (BSCF) nanocomposite (with BaCl 2 and SrCl 2 ) exhibits the low overpotential of 260 mV at 10 mA cm -2 in 0.1 M KOH. Multiple operando spectroscopic techniques reveal that the pre-leaching of soluble compounds lowers the difference of interfacial ion concentrations and thus endows the host phase in hybrid BSCF with abundant time and space to form stable edge/face-sharing surface structures. These self-optimized crystalline structures show stable lattice oxygen active sites and short reaction pathways between Co-Co/Fe metal active sites to trigger favorable adsorption of OH - species.

Background: The use of cemented and cementless fixations in primary total knee arthroplasty (TKA) in young patients is controversial. Previous reviews predominantly relied on data from retrospective studies. This systematic review and meta-analysis of randomized controlled trials (RCTs) evaluated the optimal fixation mode in TKA for young patients., Methods: The PubMed, Embase, Medline, Web of Science, and full Cochrane Library electronic databases were searched from inception to July 2018. The outcome measurements consisted of functional outcomes (Knee Society Score [KSS], range of motion [ROM]), radiolucent lines, aseptic loosening, total complications, and reoperation rate. Study data were pooled using a random-effects model., Results: Six RCTs were included in the systematic review and meta-analysis. The mean follow-up period was 12 years (range, 2-16.6 years). Cementless TKA was associated with higher KSS-function (P < .0001), higher KSS-pain (P = .005), better ROM recovery (P = .01), and fewer radiolucent lines (<1 mm) (P = .04) compared with cemented TKA. No significant intergroup differences were observed for KSS-knee, total complications, aseptic loosening, or reoperation rate. These results based on a random-effects model were unchanged by sensitivity analysis assumptions., Conclusion: Cementless TKA was substantially superior to cemented TKA in young patients. Although the complication and survival rates were similar between groups, better clinical outcomes were obtained with cementless fixation. Further well-designed studies with long follow-up durations are necessary to confirm our findings.

Background: There remains a controversy regarding the risks in subsequent total joint arthroplasty (TJA) with and without previous bariatric surgery (BS). We performed a meta-analysis based on the current evidence-based study to determine the influences of prior BS on the short-term and long-term outcomes following TJA., Methods: From the inception to July 2018, the EMBASE, PubMed, Web of Science, and Cochrane Library electronic databases were searched for all relevant English language trials. The primary outcome measures were complications and revision, whereas the secondary outcomes included length of stay and operative time. Short-term follow-up was defined as that from hospital discharge to 90 days, and long-term follow-up was defined as more than 1 year., Results: A total of 9 studies with 38,728 patients were included. Overall, medical comorbidities were higher in the BS group compared with the control morbid obesity group before TJA. Our meta-analysis revealed that BS prior to TJA was associated with reduced short-term medical complications, length of stay, and operative time. However, BS did not reduce the short-term risks for superficial wound infection or venous thromboembolism, and the long-term risks for dislocation, periprosthetic infection, periprosthetic fracture, and revision. Subgroup analysis identified a significant reduction in the risk of short-term periprosthetic infection in the BS group after total knee arthroplasty, but not after total hip arthroplasty., Conclusion: BS prior to TJA was associated with partially improved short-term outcomes after TJA. However, BS did not improve the risks for long-term outcomes. Limited by relatively higher comorbidities burden, the short-term benefits of BS should be further revealed by high-quality, controlled study in the future., (Copyright © 2018 Elsevier Inc. All rights reserved.)

We developed a thin-film silicon waveguide with gradually changing thickness for generating a near-field optical spot. Theoretical studies show that the surface plasmons that are resonantly excited on the waveguide generate a hot spot with a wide spectral range. We experimentally confirmed generation of the near-field hot spot using continuous waves at 850 and 660 nm wavelengths. This waveguide, which can generate the enhanced electric field by normal incident of the excitation beam under situations of the practical use, is promising for broadband near-field optical technologies.

To investigate if and how the breech face mark and firing pin impression change over repeated firings, we used an automated ballistic identification system Evofinder ® to study cartridge cases fired from five Chinese Norinco QSZ-92 9×19mm pistols. Each pistol fired 3070 consecutive shots. The first 20 cartridge cases were all introduced into the system. From the 21st until the 3070th shot, every ten cartridge cases were collected and one random sample of each group was introduced as the 30th, 40th, …, 3070th round. Thus, we introduced 325 specimens for each pistol and established a database of 1625 specimens. We used the first and every 100th specimen of each firearm to start correlations in the database and analyzed the results, especially the results of specimen 0001, 1000, 2000, 3000. Consequently, specimens fired closer in sequence to the specimen under examination had higher similarity scores. In boxplots, the boxes of known match specimens were much higher than boxes of known non match specimens. The Evofinder ® ranked nearly all known match specimens in the first position of either firing pin impression list or breech face mark list. In conclusion, the two marks changed over 3070 consecutive shots and cartridge cases of nearer shot numbers were more similar. However, the variations of marks from the same firearm have not exceeded the differences between marks of different firearms and have not hindered the Evofinder ® to make nearly 100% correct correlations., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This paper focuses on the fabrication of as-forged Ti46.5Al2Cr1.8Nb-(W, B) alloy via pulse current auxiliary isothermal forging (PCIF). The starting material composed of near gamma (NG) microstructure was fabricated by adopting pre-alloyed powders via hot pressing sintering (HPS) at 1300 °C. Isothermal compression tests were conducted at a strain rate range of 0.001-0.1 s -1 and a temperature range of 1125-1275 °C to establish the constitutive model and processing map. The optimal hot deformation parameters were successfully determined (in a strain rate range of 10 -3 -2.5 × 10 -3 s -1 and temperature range of 1130-1180 °C) based on the hot processing map and microstructure observation. Accordingly, an as-forged TiAl based alloy without cracks was successfully fabricated by PCIF processing at 1175 °C with a nominal strain rate of 10 -3 s -1 . Microstructure observation indicated that complete dynamic recrystallization (DRX) and phase transformation of γ→α₂ occurred during the PCIF process. The elongation of as-forged alloy was 136%, possessing a good secondary hot workability, while the sintered alloy was only 66% when tested at 900 °C with a strain rate of 2 × 10 -4 s -1 ., Competing Interests: The authors declare no conflict of interest.

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecologic malignancies. Platinum-based chemotherapy is the first-line treatment for the advanced ovarian cancer, but resistance to cisplatin remains a major obstacle to successful treatment. MicroRNAs (miRNAs) are a class of non-coding RNAs that play important roles in disease processes, including the development of drug resistance. In this study, we found miR-449a were significantly downregulated in the cisplatin-resistant ovarian cell lines SKOV3/DDP and A2780/DDP, compared with their sensitive parent line SKOV3 and A2780, respectively. The overexpression of miR-449a increased cisplatin sensitivity of SKOV3/DDP and A2780/DDP cells by inhibiting proliferation and promoting apoptosis. The luciferase assay confirmed that miR-449a functioned through suppressing NOTCH1 directly. Concordantly, BALB/c nude mice that were injected intraperitoneally with SKOV3/DDP cells transfected with miR-449a mimics exhibited enhanced cisplatin sensitivity in vivo. Taken together, these results suggest that the ectopic expression of miR-449a may be a promising therapeutic strategy for the management of cisplatin resistance in ovarian cancer.