Metal-support spin orders: Crucial effect on electrocatalytic oxygen reduction.

Magnetic property (e.g. spin order) of support is of great importance in the rational design of heterogeneous catalysts. Herein, we have taken the Ni-supported ferromagnetic (FM) CrBr3 support (Nix/CrBr3) to thoroughly investigate the effect of spin-order on electrocatalytic oxygen reduction reaction (ORR) via spin-polarized density functional theory calculations. Specifically, Ni loading induces anti-FM coupling in Ni-Cr, leading to a transition from FM-to-ferrimagnetic (FIM) properties, while Ni-Ni metallic bonds create a robust FM direct exchange, benefiting the improvement of the phase transition temperature. Interestingly, with the increase in Ni loading, the easy magnetic axis changes from out-of-plane (2D-Heisenberg) to in-plane (2D-XY). The adsorption properties of Nix/CrBr3, involving O2 adsorption energy and configuration, are not governed by the d-band center but strongly correlate with magnetic anisotropy. It is noteworthy that the applied potential and electrolyte acidity triggers spin-order transition phenomena during the ORR and induces the catalytic pathway change from 4e- ORR to 2e- ORR with the excellent onset potential of 0.93 V/reversible hydrogen electrode, comparable to the existing most excellent noble-metal catalysts. Generally, these findings offer new avenues to understand and design heterogeneous catalysts with magnetic support.

Tuning Electrocatalytic Water Oxidation Activity: Insights from the Active-Site Distance in LnCu6 Clusters.

Atomically precise metal clusters serve as a unique model for unraveling the intricate mechanism of the catalytic reaction and exploring the complex relationship between structure and activity. Herein, three series of water-soluble heterometallic clusters LnCu6, abbreviated as LnCu6-AC (Ln = La, Nd, Gd, Er, Yb; HAC = acetic acid), LnCu6-IM (Ln = La and Nd; IM = Imidazole), and LnCu6-IDA (Ln = Nd; H2IDA = Iminodiacetic acid) are presented, each featuring a uniform metallic core stabilized by distinct protected ligands. Crystal structure analysis reveals a triangular prism topology formed by six Cu2+ ions around one Ln3+ ion in LnCu6, with variations in Cu···Cu distances attributed to different ligands. Electrocatalytic oxygen evolution reaction (OER) shows that these different LnCu6 clusters exhibit different OER activities with remarkable turnover frequency of 135 s-1 for NdCu6-AC, 79 s-1 for NdCu6-IM and 32 s-1 for NdCu6-IDA. Structural analysis and Density Functional Theory (DFT) calculations underscore the correlation between shorter Cu···Cu distances and improves OER catalytic activity, emphasizing the pivotal role of active-site distance in regulating electrocatalytic OER activities. These results provide valuable insights into the OER mechanism and contribute to the design of efficient homogeneous OER electrocatalysts.

Visible-Light Photocatalytic Overall Water Splitting on a B4C3/CxNy Z-Scheme Heterojunction: Role of Ultrafast Carrier Recombination-Transfer Kinetics.

Herein, combining density functional theory (DFT) calculations with nonadiabatic molecular dynamics (NAMD), we built a computational framework to rationally screen from a series of 2D conjugated carbon nitrides (CNs) to match with B4C3, resulting in the excellent direct Z-scheme photocatalyst (B4C3/C6N6) for overall water splitting (OWS). Studies on interface engineering and ultrafast dynamics of carrier recombination-transfer show that in the B4C3/C6N6 system, compared with the slower interlayer migration process of carriers, strong nonadiabatic coupling and longer quantum decoherence time accelerates weak carrier interlayer recombination on a subpicosecond time scale, enabling simultaneous triggering of hydrogen evolution reaction (HER) with ΔG = -0.23 eV and spontaneous oxygen evolution reaction (OER) in the absence of sacrificial or cocatalysts. In general, our work will promote the design of efficient direct Z-scheme photocatalysts from an ultrafast dynamics perspective.

Co-Dissolved Isostructural Polyoxovanadates to Construct Single-Atom-Site Catalysts for Efficient CO2 Photoreduction.

We explored a co-dissolved strategy to embed mono-dispersed Pt center into V2 O5 support via dissolving [PtV9 O28 ]7- into [V10 O28 ]6- aqueous solution. The uniform dispersion of [PtV9 O28 ]7- in [V10 O28 ]6- solution allows [PtV9 O28 ]7- to be surrounded by [V10 O28 ]6- clusters via a freeze-drying process. The V centers in both [PtV9 O28 ]7- and [V10 O28 ]6- were converted into V2 O5 via a calcination process to stabilize Pt center. These double separations can effectively prevent the Pt center agglomeration during the high-temperature conversion process, and achieve 100 % utilization of Pt in [PtV9 O28 ]7- . The resulting Pt-V2 O5 single-atom-site catalysts exhibit a CH4 yield of 247.6 µmol g-1 h-1 , 25 times higher than that of Pt nanoparticle on the V2 O5 support, which was accompanied by the lactic acid photooxidation to form pyruvic acid. Systematical investigations on this unambiguous structure demonstrate an important role of Pt-O atomic pair synergy for highly efficient CO2 photoreduction.

Cooperatively interface role of surface atoms and aqueous media on single atom catalytic property for H2O2 synthesis.

Direct electrosynthesis of hydrogen peroxide (H2O2) from H2 and O2 is a promising alternative to currently industrial Riedl-Pfleiderer route. Utilizing a combination of density functional theory (DFT) and ab-initio-molecular dynamic simulation (AIMD), we presented an effective computational framework to identify the cooperative role of surface atoms(e.g. O, N and S) and aqueous media on catalytic performance of single-atom catalysts (SACs) supported Nb2C MXenes. Computational results shown that both Ni/Nb2CN2 and Co/Nb2CS2 have low overpotentials of 0.17 V and 0.20 V, and the barrier of 0.89 eV and 0.67 eV for 2e- ORR under gas phase, respectively, while in aqueous phase, hydrogen bond framework on the surface promotes the transfer of proton, resulting in the lower 2e- ORR overpotential (0.05 V) in Co/Nb2CS2 and lower barrier (almost 0.01 eV) for rate-determining step (RDS) in Ni/Nb2CN2. Electronically, we found that the less-electronegativity N and S relative to O more benefit to mediate the activation degree of O2 on SACs and thereby improve catalytic selectivity. Thus, it is concluded that both surface atom and aqueous medium synergistically promote catalytic property for H2O2 synthesis.

Causes of misdiagnosis in assessing tubal patency by transvaginal real-time three-dimensional hysterosalpingo-contrast sonography.

OBJECTIVE: This study aims to investigate the causes of misdiagnosis in assessing tubal patency by transvaginal real-time three-dimensional hysterosalpingo-contrast sonography (TVS RT-3D-HyCoSy), in order to improve the diagnostic efficiency of TVS RT-3D-HyCoSy. METHODS: A total of 162 oviducts of 83 infertility patients were examined by TVS RT-3D-HyCoSy. These results were compared with the gold standard for laparoscopic dye studies, and the misdiagnosed cases were analyzed. RESULTS: TVS RT-3D-HyCoSy revealed that 68 oviducts were unobstructed and 94 obstructed. The results for the 144 oviducts were in line with the gold standard, while those for 18 oviducts were not. The accuracy rate of the TVS RT-3D-HyCoSy was 88.9%, and the misdiagnosis rate was 11.1%. The main causes of misdiagnosis included contrast medium countercurrent and diffusion, oviduct spasm, abnormal shape or position of the oviduct, pelvic adhesion, and poor imaging operation. CONCLUSION: TVS RT-3D-HyCoSy can well-evaluate tubal patency, and understand and improve the cause of misdiagnosis. Furthermore, the diagnostic efficiency of TVS RT-3D-HyCoSy can still be further improved.

Causes of misdiagnosis in assessing tubal patency by transvaginal real-time three-dimensional hysterosalpingo-contrast sonography

SUMMARY OBJECTIVE This study aims to investigate the causes of misdiagnosis in assessing tubal patency by transvaginal real-time three-dimensional hysterosalpingo-contrast sonography (TVS RT-3D-HyCoSy), in order to improve the diagnostic efficiency of TVS RT-3D-HyCoSy. METHODS A total of 162 oviducts of 83 infertility patients were examined by TVS RT-3D-HyCoSy. These results were compared with the gold standard for laparoscopic dye studies, and the misdiagnosed cases were analyzed. RESULTS TVS RT-3D-HyCoSy revealed that 68 oviducts were unobstructed and 94 obstructed. The results for the 144 oviducts were in line with the gold standard, while those for 18 oviducts were not. The accuracy rate of the TVS RT-3D-HyCoSy was 88.9%, and the misdiagnosis rate was 11.1%. The main causes of misdiagnosis included contrast medium countercurrent and diffusion, oviduct spasm, abnormal shape or position of the oviduct, pelvic adhesion, and poor imaging operation. CONCLUSION TVS RT-3D-HyCoSy can well-evaluate tubal patency, and understand and improve the cause of misdiagnosis. Furthermore, the diagnostic efficiency of TVS RT-3D-HyCoSy can still be further improved.

RESUMO OBJETIVO Este estudo tem como objetivo investigar as causas do diagnóstico equivocado na avaliação da patência tubária por meio da ultrassonografia de contraste histerosalpingo em tempo real transvaginal (TVS RT-3D-HyCoSy), a fim de melhorar a eficiência diagnóstica das TVS RT-3D-HyCoSy. MÉTODOS Um total de 162 ovidutos em 83 pacientes da infertilidade foi examinado por TVS RT-3D-HyCoSy. Esses resultados foram comparados com o padrão ouro para estudos de tintura laparoscópica, e os casos diagnosticados erroneamente foram analisados. RESULTADOS TVS RT-3D-HyCoSy revelaram que 68 ovidutos foram desobstruídos e 94 ovidutos foram obstruídos. Os resultados para os 144 ovidutos estavam em consonância com o padrão ouro, enquanto que aqueles para os 18 ovidutos, não. A taxa de acurácia do TVS RT-3D-HyCoSy foi de 88,9%, e a taxa de erro de diagnóstico foi de 11,1%. As principais causas de erro de diagnóstico incluíram contraponto e difusão do meio de contraste, espasmo do oviduto, forma ou posição anormal do oviduto, adesão pélvica e má operação de imagem. CONCLUSÃO TVS RT-3D-HyCoSy pode bem avaliar a patência tubária, e compreender e melhorar a causa do erro de diagnóstico. Além disso, a eficiência diagnóstica do TVS RT-3D-HyCoSy ainda pode ser melhorada.

SIRT1 acts as a potential tumor suppressor in oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most common malignant tumor in oral cancer, however, the mechanism underlying OSCC tumorigenesis is unknown. SIRT1, has been considered a prominent tumor-suppressing/promoting gene in various solid tumors, although the precise role of SIRT1 in OSCC progression remains unknown. METHODS: SIRT1 expression was assessed in surgically resected specimens from patients with OSCC for histopathologic factors. SIRT1 levels in OSCC were determined, SIRT1 overexpression was achieved on transfecting OSCC cells with a SIRT1-containing plasmid, followed by evaluation of proliferative ability and invasiveness of these cells. RESULTS: SIRT1 levels were significantly lower in patients with OSCC than in controls (p < 0.05). Moreover, SIRT1 levels in patients with OSCC were significantly associated with the lymphovascular permeation but not with the sex, age, stage and location. Furthermore, SIRT1 overexpression inhibited proliferation and invasion in OSCC cells. CONCLUSION: The present results suggest that SIRT1 is a potential tumor suppressor in OSCC.