Amniotic Fluid Proteomics Analysis and In Vitro Validation to Identify Potential Biomarkers of Preterm Birth.

This study aimed to investigate the regulation of amniotic fibroblast (AFC) function by vitamin K-dependent protein Z (PROZ) during preterm birth (PTB) and its potential role in adverse pregnancy outcomes. Proteomic samples were collected from amniotic fluid in the second trimester, and AFC were isolated from the amniotic membrane and cultured in vitro. The expression of extracellular and intracellular PROZ in AFC was modulated, and their biological properties and functions were evaluated. Clinical analysis revealed a significant upregulation of PROZ expression in amniotic fluid from preterm pregnant women. In vitro experiments demonstrated that PROZ stimulated AFC migration, enhanced their proliferative capacity, and reduced collagen secretion. Overexpression of PROZ further enhanced cell migration and proliferation, while knockdown of PROZ had the opposite effect. PROZ plays a crucial role in promoting the proliferation and migration of amniotic membrane fibroblasts. Increased PROZ expression in amniotic fluid is associated with the occurrence of PTB. These findings shed light on the potential involvement of PROZ in adverse pregnancy outcomes and provide a basis for further research on its regulatory mechanisms during PTB.

Locking the lattice oxygen in RuO2 to stabilize highly active Ru sites in acidic water oxidation.

Ruthenium dioxide is presently the most active catalyst for the oxygen evolution reaction (OER) in acidic media but suffers from severe Ru dissolution resulting from the high covalency of Ru-O bonds triggering lattice oxygen oxidation. Here, we report an interstitial silicon-doping strategy to stabilize the highly active Ru sites of RuO2 while suppressing lattice oxygen oxidation. The representative Si-RuO2-0.1 catalyst exhibits high activity and stability in acid with a negligible degradation rate of ~52 µV h-1 in an 800 h test and an overpotential of 226 mV at 10 mA cm-2. Differential electrochemical mass spectrometry (DEMS) results demonstrate that the lattice oxygen oxidation pathway of the Si-RuO2-0.1 was suppressed by ∼95% compared to that of commercial RuO2, which is highly responsible for the extraordinary stability. This work supplied a unique mentality to guide future developments on Ru-based oxide catalysts' stability in an acidic environment.

Plasma-induced nitrogen vacancy-mediated ammonia synthesis over a VN catalyst.

Plasma catalysis has recently been recognized as a promising route for artificial N2 reduction under mild conditions. Here we report a highly active VN catalyst for plasma-catalytic NH3 synthesis via the typical Mars-van Krevelen (MvK) mechanism. Our results indicate that NH3 synthesis occurs through the continuous regeneration and elimination of nitrogen vacancies on the VN surface. With this strategy, the VN catalyst achieves a superhigh NH3 yield of 143.2 mg h-1 gcat.-1 and a competitive energy efficiency of 1.43 gNH3 kW h-1.

The role of nitrogen sources and hydrogen adsorption on the dynamic stability of Fe-N-C catalysts in oxygen reduction reaction.

Fe-N-C catalysts are promising alternatives to Pt-based electrocatalysts for the oxygen reduction reaction (ORR) in various electrochemical applications. However, their practical implementation is impeded by their instability during prolonged operation. Various degradation mechanisms have been proposed, yet the real origin of the intrinsic instability of Fe-N-C structures under ORR operations is still disputed. Herein, we observed a new type of protonation mechanism based on advanced first-principles simulations and experimental characterizations. The results revealed strong evidence of pyrrolic-N protonation in pyrrolic-type FeN4, which plays a vital role for the low kinetic barrier of Fe leaching. Conversely, the pyridinic-type FeN4 prefers protonation at the Fe site, contributing to the higher barrier of Fe leaching and relatively higher stability. The facile pyrrolic-N protonation is verified by various spectroscopy characterizations in the Nafion-treated FePc molecule. Crucially, the presence of oxygen-containing intermediates at the Fe site can further work synergistically with N protonation to promote conversion of iron atoms (Fe-N4) into ferric oxide under working potentials, and the more positive the electrode potential, the lower the kinetic barrier of Fe leaching. These findings serve as a foundation for future research endeavors on the stability issues of Fe-N-C catalysts and advancing their application in sustainable energy conversion technologies.

A phosphate tolerant Pt-based oxygen reduction catalyst enabled by synergistic modulation of alloying and surface modification.

Addressing phosphoric acid poisoning of platinum-based catalysts in high-temperature fuel cells still remains a strategic and synthetic problem. Here, we synthesized a Pt3Co@MoOx-NC catalyst with a Pt3Co active core and MoOx modification on the surface, which simultaneously exhibits high ORR activity and phosphate tolerance.

Correction: Strengthening Pt/WOx interfacial interactions to increase the CO tolerance of Pt for hydrogen oxidation reaction.

Correction for 'Strengthening Pt/WOx interfacial interactions to increase the CO tolerance of Pt for hydrogen oxidation reaction' by Daojun Long et al., Chem. Commun., 2023, https://doi.org/10.1039/d3cc03990k.

Strengthening Pt/WOx interfacial interactions to increase the CO tolerance of Pt for hydrogen oxidation reaction.

Here, the modulation of the Pt electronic structure by the formation of an amorphous WOx overlayer on Pt nanoparticles is proposed. The resulting Pt/WOx@NC electrode shows exceptional CO oxidation potential (0.24 V vs. RHE) in aqueous test, and the corresponding membrane electrode assembly (MEA) steadily generates power in fuel cells fed with H2 gas containing 1000 ppm CO.

Maximizing metal utilization by coupling cross-linked PtRu multi-atom on an atomically dispersed ZnFeNC support.

Minimizing noble-metal (NM) usage by exposing all metal atoms on surfaces for catalysis has been a longstanding goal in the development of highly efficient NM catalysts. Here, we realized the full utilization of Pt and Ru atoms by anchoring the cross-linked PtRu multi-atom on the surface of atomically dispersed Zn, Fe and N tri-doped carbon nanomaterials through Pt-N and Ru-N bonds. This supported bimetallic PtRu multi-atom catalyst has extremely high atom efficiency and shows excellent stability and high activity towards the methanol oxidation reaction (MOR). Density functional theory (DFT) calculations reveal that the strongly coupled Pt-N and Ru-N bonds are critical for stabilizing multi-atom PtRu.

Precisely tuning the electronic structure of a structurally ordered PtCoFe alloy via a dual-component promoter strategy for oxygen reduction.

Optimizing the electronic structure of Pt-based alloys has emerged as an effective strategy to further improve their catalytic oxygen reduction reaction (ORR) performance, yet this remains challenging. Here, we have successfully tuned the electronic structure of ordered PtCoFe nanoparticles by incorporating the third component (Fe) into a bimetallic ordered PtCo alloy and manipulating its content. With the merits of the optimum electronic structure and the favorable composition, as well as the robust ordered structure, the as-prepared ordered PtCoFe-1-0.6 alloy (1 and 0.6 represent the feeding molar ratio of Co to Pt and Fe to Pt, respectively) exhibits enhanced catalytic performance for ORR. The L10-PtCoFe-1-0.6 alloy delivers higher specific activity (2.23 mA cm-2) than bimetallic L10-PtCo-1 (1.34 mA cm-2) and the commercial Pt/C (0.23 mA cm-2) catalyst. Indeed, this dual-catalytic-component promoter strategy gives a significant insight into developing high-performance homogeneous catalysts.

Manipulating the surface composition of Pt-Ru bimetallic nanoparticles to control the methanol oxidation reaction pathway.

The rational manipulation of reaction intermediates is crucial for achieving high-performance heterogeneous catalysis. Herein, using in situ Fourier transform infrared-diffuse reflection (FTIR) analysis, we report that the methanol oxidation reaction (MOR) intermediates can be controlled by precisely tuning the location and content of Ru on the Pt-Ru alloy surface.

Leaching- and sintering-resistant hollow or structurally ordered intermetallic PtFe alloy catalysts for oxygen reduction reactions.

Carbon supported Pt-based alloy materials that have been developed for proton exchange membrane fuel cells (PEMFCs) are vulnerable to deactivation due to the loss of non-noble metal components (leaching) or detachment, migration and aggregation of active nanoparticles (sintering). Until now some methods have been developed to inhibit leaching or sintering individually. However, a route able to avoid leaching and sintering simultaneously is still lacking. Herein, we develop a thermally driven interfacial diffusion alloying route that allows for the direct evolution of solid Pt nanoparticles (NPs) supported on carbon (Pt/C) into a Pt-skin-like hollow PtFe alloy or a structurally ordered intermetallic PtFe alloy, together with in situ encapsulation of PtFe alloy NPs with a thin layer porous nitrogen-doped carbon (NC) shell. The robust NC shells not only effectively prevent Pt-based NPs from detachment, migration, and aggregation during accelerated durability tests but also allow smoother access of electrolyte to the Pt surface, thus allowing the catalysts to well preserve their high catalytic activity. The well-defined shape and atomic arrangement of PtFe alloy NPs exhibit over 600% increase in mass activity and specific activity when compared with that of the pristine Pt/C catalyst. Stability tests confirm that the ordered PtFe alloy is more electrochemically stable than the disordered hollow PtFe alloy and Pt/C catalysts due to its ordered atomic arrangement and the robust NC shell.

High temperature self-assembly one-step synthesis of a structurally ordered PtFe catalyst for the oxygen reduction reaction.

Herein, we present a high-temperature self-assembly strategy that directly allows the transformation of adsorbed Pt(NH3)42+ and Fe3+ sources into structurally ordered face-centered tetragonal (fct)-PtFe alloy NPs (2.6 ± 0.2 nm) by integrating reduction and phase transformation. The small-size and ordered atomic arrangement of the fct-PtFe alloy NPs, together with their robust NC protective shell, make these NPs exhibit excellent catalytic activity and stability for the oxygen reduction reaction.

NaCl protected synthesis of 3D hierarchical metal-free porous nitrogen-doped carbon catalysts for the oxygen reduction reaction in acidic electrolyte.

A high-performance 3D hierarchical porous metal-free N-doped carbon catalyst toward the oxygen reduction reaction (ORR) in acidic medium was successfully synthesized by employing ZnO as a mesoporous template and NaCl as both a macroporous template and a structure protective agent. The resultant improved active site density and diffusion efficiency lead to a superior ORR activity with a half-wave potential high up to 0.755 V in 0.1 M HClO4.

Ultrahigh-Loading Zinc Single-Atom Catalyst for Highly Efficient Oxygen Reduction in Both Acidic and Alkaline Media.

Atomically dispersed Zn-N-C nanomaterials are promising platinum-free catalysts for the oxygen reduction reaction (ORR). However, the fabrication of Zn-N-C catalysts with a high Zn loading remains a formidable challenge owing to the high volatility of the Zn precursor during high-temperature annealing. Herein, we report that an atomically dispersed Zn-N-C catalyst with an ultrahigh Zn loading of 9.33 wt % could be successfully prepared by simply adopting a very low annealing rate of 1° min-1 . The Zn-N-C catalyst exhibited comparable ORR activity to that of Fe-N-C catalysts, and significantly better ORR stability than Fe-N-C catalysts in both acidic and alkaline media. Further experiments and DFT calculations demonstrated that the Zn-N-C catalyst was less susceptible to protonation than the corresponding Fe-N-C catalyst in an acidic medium. DFT calculations revealed that the Zn-N4 structure is more electrochemically stable than the Fe-N4 structure during the ORR process.

Three-Dimensional Fe,N-Decorated Carbon-Supported NiFeP Nanoparticles as an Efficient Bifunctional Catalyst for Rechargeable Zinc-O2 Batteries.

The electro-catalyzed oxygen reduction and evolution reactions (ORR/OER) are the key elements of many energy conversion systems, such as fuel cells, water electrolyzers, and rechargeable metal-air batteries. Structural design of durable non-noble nanomaterials as bifunctional OER/ORR catalysts is a major drawback to commercial applications. Herein, we exposed a strongly coupled hybrid material comprising of NiFeP-cubes nanoparticles supported on three-dimensional interconnected Fe,N-decorated carbon (3D-FeNC) as a robust bifunctional ORR/OER catalyst. The strongly coupled NiFeP@3D-FeNC catalyst shows better electron and mass transfer capability, exposure of abundant ORR/OER active sites on the surface, and strongly coupled effects. Accordingly, the as-prepared NiFeP@3D-FeNC catalyst exhibits robust ORR activity (half-wave potential of 0.84 V vs reversible hydrogen electrode) and OER performance (over-potential 0.25 V@10 mA cm-2) in alkaline media. Significantly, the oxygen electrode prepared from the NiFeP@3D-FeNC catalyst further demonstrated superior charge/discharge behavior and long-lasting rechargeability than the benchmark Pt/C + IrO2 catalyst in rechargeable zinc-O2 batteries. This approach opens up a new avenue for the synthesis and advanced the hybrid nanomaterials for various applications.

Construction of a porous nitrogen-doped carbon nanotube with open-ended channels to effectively utilize the active sites for excellent oxygen reduction reaction activity.

We rationally designed and controllably fabricated a well-defined porous nitrogen-doped carbon nanotube with open-ended channels as a catalyst for the ORR by a twice pseudomorphic transformation of MnO2 nanotubes. The as-prepared O-NCNT catalysts exhibit an expectably remarkable performance, indicating the potential for replacing Pt-based catalysts in fuel cells and metal-air batteries.

Structural Evolution of Solid Pt Nanoparticles to a Hollow PtFe Alloy with a Pt-Skin Surface via Space-Confined Pyrolysis and the Nanoscale Kirkendall Effect.

A space-confined interfacial conversion approach is developed to directly transform 3 nm solid Pt nanoparticles into a 5 nm hollow PtFe alloy featuring a Pt-skin surface. The approach presented for the structural evolution from solid Pt NPs to hollow PtFe alloy with controlled size, structure, and composition can be applied to other multimetallic electrocatalysts.

A Strategy to Promote the Electrocatalytic Activity of Spinels for Oxygen Reduction by Structure Reversal.

The electrocatalytic performance of a spinel for the oxygen reduction reaction (ORR) can be significantly promoted by reversing its crystalline structure from the normal to the inverse. As the spinel structure reversed, the activation and cleavage of O-O bonds are accelerated owing to a dissimilarity effect of the distinct metal atoms co-occupying octahedral sites. The Co(II)Fe(III)Co(III)O4 spinel with the Fe and Co co-occupying inverse structure exhibits an excellent ORR activity, which even exceeds that of the state-of-the-art commercial Pt/C by 42 mV in alkaline medium.

SIRT1 and FOXO Mediate Contractile Differentiation of Vascular Smooth Muscle Cells under Cyclic Stretch.

BACKGROUND/AIMS: Physiological mechanical stretch in vivo helps to maintain the quiescent contractile differentiation of vascular smooth muscle cells (VSMCs), but the underlying mechanisms are still unclear. Here, we investigated the effects of SIRT1 in VSMC differentiation in response to mechanical cyclic stretch. METHODS AND RESULTS: Rat VSMCs were subjected to 10%-1.25Hz-cyclic stretch in vitro using a FX-4000T system. The data indicated that the expression of contractile markers, including α-actin, calponin and SM22α, was significantly enhanced in VSMCs that were subjected to cyclic stretch compared to the static controls. The expression of SIRT1 and FOXO3a was increased by the stretch, but the expression of FOXO4 was decreased. Decreasing SIRT1 by siRNA transfection attenuated the stretch-induced expression of contractile VSMC markers and FOXO3a. Furthermore, increasing SIRT1 by either treatment with activator resveratrol or transfection with a plasmid to induce overexpression increased the expression of FOXO3a and contractile markers, and decreased the expression of FOXO4 in VSMCs. Similar trends were observed in VSMCs of SIRT1 (+/-) knockout mice. The overexpression of FOXO3a promoted the expression of contractile markers in VSMCs, while the overexpression of FOXO4 demonstrated the opposite effect. CONCLUSION: Our results indicated that physiological cyclic stretch promotes the contractile differentiation of VSMCs via the SIRT1/FOXO pathways and thus contributes to maintaining vascular homeostasis.

Shape Fixing via Salt Recrystallization: A Morphology-Controlled Approach To Convert Nanostructured Polymer to Carbon Nanomaterial as a Highly Active Catalyst for Oxygen Reduction Reaction.

Herein, we report a "shape fixing via salt recrystallization" method to efficiently synthesize nitrogen-doped carbon material with a large number of active sites exposed to the three-phase zones, for use as an ORR catalyst. Self-assembled polyaniline with a 3D network structure was fixed and fully sealed inside NaCl via recrystallization of NaCl solution. During pyrolysis, the NaCl crystal functions as a fully sealed nanoreactor, which facilitates nitrogen incorporation and graphitization. The gasification in such a closed nanoreactor creates a large number of pores in the resultant samples. The 3D network structure, which is conducive to mass transport and high utilization of active sites, was found to have been accurately transferred to the final N-doped carbon materials, after dissolution of the NaCl. Use of the invented cathode catalyst in a proton exchange membrane fuel cell produces a peak power of 600 mW cm(-2), making this among the best nonprecious metal catalysts for the ORR reported so far. Furthermore, N-doped carbon materials with a nanotube or nanoshell morphology can be realized by the invented method.