MFN2 Prevents Neointimal Hyperplasia in Vein Grafts via Destabilizing PFK1.

BACKGROUND: Mechanical forces play crucial roles in neointimal hyperplasia after vein grafting; yet, our understanding of their influences on vascular smooth muscle cell (VSMC) activation remains rudimentary. METHODS: A cuff mouse model was used to study vein graft hyperplasia. Fifteen percent to 1 Hz uniaxial cyclic stretch (arterial strain), 5% to 1 Hz uniaxial cyclic stretch or a static condition (venous strain) were applied to the cultured VSMCs. Metabolomics analysis, cell proliferation and migration assays, immunoblotting, co-immunoprecipitation, mutagenesis, pull-down and surface plasmon resonance assays were employed to elucidate the potential molecular mechanisms. RESULTS: RNA-sequencing in vein grafts and the controls identified changes in metabolic pathways and downregulation of mitochondrial protein MFN2 (mitofusin 2) in the vein grafts. Exposure of VSMCs to 15% stretch resulted in MFN2 downregulation, mitochondrial fragmentation, metabolic shift from mitochondrial oxidative phosphorylation to glycolysis, and cell proliferation and migration, as compared with that to a static condition or 5% stretch. Metabolomics analysis indicated an increased generation of fructose 1,6-bisphosphate, an intermediate in the glycolytic pathway converted by PFK1 (phosphofructokinase 1) from fructose-6-phosphate, in cells exposed to 15% stretch. Mechanistic study revealed that MFN2 physically interacts through its C-terminus with PFK1. MFN2 knockdown or exposure of cells to 15% stretch promoted stabilization of PFK1, likely through interfering the association between PFK1 and the E3 ubiquitin ligase TRIM21 (E3 ubiquitin ligase tripartite motif [TRIM]-containing protein 21), thus, decreasing the ubiquitin-protease-dependent PFK1 degradation. In addition, study of mechanotransduction utilizing pharmaceutical inhibition indicated that the MFN2 downregulation by 15% stretch was dependent on inactivation of the SP1 (specificity protein 1) and activation of the JNK (c-Jun N-terminal kinase) and ROCK (Rho-associated protein kinase). Adenovirus-mediated MFN2 overexpression or pharmaceutical inhibition of PFK1 suppressed the 15% stretch-induced VSMC proliferation and migration and alleviated neointimal hyperplasia in vein grafts. CONCLUSIONS: MFN2 is a mechanoresponsive protein that interacts with PFK1 to mediate PFK1 degradation and therefore suppresses glycolysis in VSMCs.

Understanding the complexity in bridging thermal and electrocatalytic methanation of CO2.

The selective methanation of CO2 is an important research area to meet the net-zero emission targets. Furthermore, it is crucial to develop solutions to achieve carbon neutrality, hydrogen utilization, carbon circularity, and chemical-energy storage. This conversion can be realized via the thermocatalytic multistep power-to-X route or by direct electro- (or photoelectro)-catalytic technologies. Herein, we discuss the need to accelerate direct technologies. Improving these technologies requires a better understanding of the catalytic chemistry and the complexity of the aspects to consider in bridging catalytic and electrocatalytic CO2 methanation. In this tutorial review, initially we analyze the fundamental question of the competitive adsorption of key reactants and regulation strategies to promote the overall reaction. Then, this approach is used to guide the reader in understanding the differences between thermocatalysis and electrocatalysis. Finally, the complexity of the aspects necessary to include in modelling and designing next-generation electrocatalysts for CO2 methanation is analyzed.

Transfer-Imprinting-Assisted Growth of 2D/3D Perovskite Heterojunction for Efficient and Stable Flexible Inverted Perovskite Solar Cells.

2D/3D perovskite heterostructures show great potential to boost efficiency and stability of perovskite solar cells (PSCs). Here, a solvent-free transfer-imprinting-assisted growth (TIAG) method is employed to in situ grow 2D/3D perovskite heterojunctions. The solid-state transfer of spacer cation by the TIAG process enables a spatially confined growth of the 2D perovskite interlayer with uniform morphology between the 3D perovskites and charge transport layer. Meanwhile, the pressure associated with the TIAG process promotes the crystalline orientation, which is beneficial to carrier transport. As a result, the inverted PSC achieved a PCE of 23.09% (with certified 22.93%) and maintained 90% of their initial PCE after aging at 85 °C for 1200 h or operating for 1100 h under continuous AM 1.5 illumination. Flexible inverted PSCs achieved a PCE of 21.14% with mechanical robustness by maintaining above 80% of their initial PCE after 10000 bending cycles under a 3 mm bending radius.

High-Resolution Patterning of Perovskite Quantum Dots via Femtosecond Laser-Induced Forward Transfer.

High-resolution patterning of perovskite quantum dots (PQDs) is of significant importance for satisfying various practical applications, including high-resolution displays and image sensing. However, due to the limitation of the instability of PQDs, the existing patterning strategy always involves chemical reagent treatment or mask contact that is not suitable for PQDs. Therefore, it is still a challenge to fabricate high-resolution full-color PQD arrays. Here, we present a femtosecond laser-induced forward transfer (FsLIFT) technology, which enables the programmable fabrication of high-resolution full-color PQD arrays and arbitrary micropatterns. The FsLIFT process integrates transfer, deposition, patterning, and alignment in one step without involving a mask and chemical reagent treatment, guaranteeing the preservation of the photophysical properties of PQDs. A full-color PQD array with a high resolution of 2 µm has been successfully achieved. We anticipate that our facile and flexible FsLIFT technology can facilitate the development of diverse practical applications based on patterned PQDs.

In Situ Visualization and Mechanistic Understandings on Facet-Dependent Atomic Redispersion of Platinum on CeO2.

Redispersion is an effective method for regeneration of sintered metal-supported catalysts. However, the ambiguous mechanistic understanding hinders the delicate controlling of active metals at the atomic level. Herein, the redispersion mechanism of atomically dispersed Pt on CeO2 is revealed and manipulated by in situ techniques combining well-designed model catalysts. Pt nanoparticles (NPs) sintered on CeO2 nano-octahedra under reduction and oxidation conditions, while redispersed on CeO2 nanocubes above ∼500 °C in an oxidizing atmosphere. The dynamic shrinkage and disappearance of Pt NPs on CeO2 (100) facets was directly visualized by in situ TEM. The generated atomically dispersed Pt with the square-planar [PtO4]2+ structure on CeO2 (100) facets was also confirmed by combining Cs-corrected STEM and spectroscopy techniques. The redispersion and atomic control were ascribed to the high mobility of PtO2 at high temperatures and its strong binding with square-planar O4 sites over CeO2 (100). These understandings are important for the regulation of atomically dispersed platinum catalysts.

Partial Sulphidation to Regulate Coordination Structure of Single Nickel Atoms on Graphitic Carbon Nitride for Efficient Solar H2 Evolution.

To develop a non-precious highly efficient cocatalyst to replace Pt on graphitic carbon nitride (g-C3 N4 ) for solar H2 production is great significant, but still remains a huge challenge. The emerging single-atom catalyst presents a promising strategy for developing highly efficient non-precious cocatalyst owing to its unique adjustability of local coordination environment and electronic structure. Herein, this work presents a facile approach to achieve single Ni sites (Ni1 -N2 S) with unique local coordination structure featuring one Ni atom coordinated with two nitrogen atoms and one sulfur atom, confirmed by high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, and density functional theory calculation. Thanks to the unique electron structure of Ni1 -N2 S sites, the 1095 µmol g-1 h-1 of high H2 evolution rate with 4.1% of apparent quantum yield at 420 nm are achieved. This work paves a pathway for designing a highly efficient non-precious transition metal cocatalyst for photocatalytic H2 evolution.

Nanoscale control of non-reciprocal ripple writing.

Femtosecond laser-induced deep-subwavelength structures have attracted much attention as a nanoscale surface texturization technique. A better understanding of the formation conditions and period control is required. Herein, we report a method of non-reciprocal writing via a tailored optical far-field exposure, where the period of ripples varies along different scanning directions, and achieve a continuous manipulation of the period from 47 to 112 nm (±4 nm) for a 100-nm-thick indium tin oxide (ITO) on glass. A full electromagnetic model was developed to demonstrate the redistributed localized near-field at different stages of ablation with nanoscale precision. It explains the formation of ripples and the asymmetry of the focal spot determines the non-reciprocity of ripple writing. Combined with beam shaping techniques, we achieved non-reciprocal writing (regarding scanning direction) using an aperture-shaped beam. The non-reciprocal writing is expected to open new paths for precise and controllable nanoscale surface texturing.

Optical near fields for ablation of periodic structures.

The formation mechanism of laser-induced periodic surface structures (LIPSS) has been a key to high-resolution sub-diffraction lithography or high-efficiency large-area nanotexturing. We show the evolution of LIPSS formation from a nanohole seed structure to high-spatial-frequency LIPSS by using a tightly focused and rectangular-shaped laser beam with different shape-polarization orientations. Formation of LIPSS based on light intensity distribution without invoking any long-range electromagnetic modes achieved quantitative match between modeling and experiment. Our results clearly show the entire step-like and deterministic process of LIPSS evolution based on experimental data and numerical simulations, revealing the dominant structural near-field enhancement on the ripple formation. A rectangular-shaped beam with an aspect ratio of 7:3 was used to break the symmetry of a circularly shaped focus. By azimuthally rotating the orientation of the focal spot and the polarization, it is possible to visualize the far-field effect for the initial seed structure formation and the competition between the far and near fields in the subsequent structure evolution.

Metal-Free Electrocatalysts for the Selective 2 e- Oxygen Reduction Reaction: A Never-Ending Story?

Hydrogen peroxide (H2 O2 ) electrosynthesis via the 2e- Oxygen Reduction Reaction (ORR) represents a highly challenging, environmentally friendly and cost-effective alternative to the current anthraquinone-based technology. Various lightweight element hetero-doped carbon nanostructures are promising and cheap metal-free electrocatalysts for H2 O2 synthesis, particularly those containing O-functionalities. The exact role of O-containing functional groups as electroactive sites for the process remains debated if not highly controversial. Herein, we have reported on the covalent exohedral functionalization of the outer surface of extra-pure multi-walled carbon nanotubes (MWCNTs) with discrete O-functional groups as a unique approach to prepare selective electrocatalysts for the process. This kind of decoration has added fundamental tiles to the puzzling structure/reactivity relationship of O-containing carbon-based catalysts for ORR, clearing doubts on the controversial role of hydroxyl/phenol groups as key functionalities for the design of more performing 2e- ORR electrocatalysts.

Overexpression of SH2D1A promotes cancer progression and is associated with immune cell infiltration in hepatocellular carcinoma via bioinformatics and in vitro study.

BACKGROUND: SH2 domain containing 1A (SH2D1A) expression has been linked to cancer progression. However, the functions of SH2D1A in hepatocellular carcinoma (HCC) have not been reported. METHODS: The effects of SH2D1A on the proliferation, migration, and invasion of HCC cells and the related pathways were re-explored in cell models with SH2D1A overexpression using the CCK-8, migration and invasion assays and western blotting. The functions and mechanisms of genes co-expressed with SH2D1A were analyzed using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The relationship between SH2D1A expression and immune microenvironment features in HCC was explored. RESULTS: Elevated SH2D1A expression promoted cell proliferation, migration, and invasion, which was related to the overexpression of p-Nf-κB and BCL2A1 protein levels in HCC. SH2D1A expression was related to the immune, stromal, and ESTIMATE scores, and the abundance of immune cells, such as B cells, CD8+ T cells, and T cells. SH2D1A expression was significantly related to the expression of immune cell markers, such as PDCD1, CD8A, and CTLA4 in HCC. CONCLUSION: SH2D1A overexpression was found to promote cell growth and metastasis via the Nf-κB signaling pathway and may be related to the immune microenvironment in HCC. The findings indicate that SH2D1A can function as a biomarker in HCC.

Improved Performance of All-Inorganic Perovskite Light-emitting Diodes via Nanostructured Stamp Imprinting.

Halide perovskites are emerging emitters with excellent optoelectronic properties. Contrary to the large grain fabrication goal in perovskite solar cells, perovskite light-emitting diodes (PeLEDs) based on small grain enable efficient radiative recombination because of relatively higher charge carrier densities due to spatial confinement. However, achieving small-sized grain growth with superior crystal quality and film morphology remains a challenge. In this work, we demonstrated a nanostructured stamp thermal imprinting strategy to boost the surface coverage and improve the crystalline quality of CsPbBr3 film, particularly confine the grain size, leading to the improvement of luminance and efficiency of PeLEDs. We improved the thermal imprinting process utilizing the nanostructured stamp to selectively manipulate the nucleation and growth in the nanoscale region and acquire small-sized grain accompanied by improved crystal quality and surface morphology of the film. By optimizing the imprinting pressure and the period of the nanostructures, appropriate grain size, high surface coverage, small surface roughness and improved crystallization could be achieved synchronously. Finally, the maximum luminance and efficiency of PeLEDs achieved by nanostructured stamp imprinting with a period of 320 nm are 67600 cd/m2 and 16.36 cd/A, respectively. This corresponds to improvements of 123 % in luminance and 100 % in efficiency, compared to that of PeLEDs without the imprinting.

Porous Silicon Carbide (SiC): A Chance for Improving Catalysts or Just Another Active-Phase Carrier?

There is an obvious gap between efforts dedicated to the control of chemicophysical and morphological properties of catalyst active phases and the attention paid to the search of new materials to be employed as functional carriers in the upgrading of heterogeneous catalysts. Economic constraints and common habits in preparing heterogeneous catalysts have narrowed the selection of active-phase carriers to a handful of materials: oxide-based ceramics (e.g. Al2O3, SiO2, TiO2, and aluminosilicates-zeolites) and carbon. However, these carriers occasionally face chemicophysical constraints that limit their application in catalysis. For instance, oxides are easily corroded by acids or bases, and carbon is not resistant to oxidation. Therefore, these carriers cannot be recycled. Moreover, the poor thermal conductivity of metal oxide carriers often translates into permanent alterations of the catalyst active sites (i.e. metal active-phase sintering) that compromise the catalyst performance and its lifetime on run. Therefore, the development of new carriers for the design and synthesis of advanced functional catalytic materials and processes is an urgent priority for the heterogeneous catalysis of the future. Silicon carbide (SiC) is a non-oxide semiconductor with unique chemicophysical properties that make it highly attractive in several branches of catalysis. Accordingly, the past decade has witnessed a large increase of reports dedicated to the design of SiC-based catalysts, also in light of a steadily growing portfolio of porous SiC materials covering a wide range of well-controlled pore structure and surface properties. This review article provides a comprehensive overview on the synthesis and use of macro/mesoporous SiC materials in catalysis, stressing their unique features for the design of efficient, cost-effective, and easy to scale-up heterogeneous catalysts, outlining their success where other and more classical oxide-based supports failed. All applications of SiC in catalysis will be reviewed from the perspective of a given chemical reaction, highlighting all improvements rising from the use of SiC in terms of activity, selectivity, and process sustainability. We feel that the experienced viewpoint of SiC-based catalyst producers and end users (these authors) and their critical presentation of a comprehensive overview on the applications of SiC in catalysis will help the readership to create its own opinion on the central role of SiC for the future of heterogeneous catalysis.

In Situ Investigations on Structural Evolutions during the Facile Synthesis of Cubic α-MoC1-x Catalysts.

Cubic α-phase molybdenum carbides (α-MoC1-x) exhibit great potential in hydrogen production at low temperatures due to their excellent activity in water dissociation. However, the design strategies of α-MoC1-x are severely restricted by the harsh synthesis conditions, which involve multistep ammonification and carburization or the utilization of a significant amount of noble metals. Herein, high-purity α-MoC1-x synthesis in a one-step carburization process was achieved with the assistance of a trace amount of Rh (0.02%). The structural evolution of Mo species during phase transition was monitored via qualitative and quantitative analysis by in situ X-ray diffraction (XRD) and in situ X-ray absorption spectroscopy (XAS), respectively. Environmental transmission electron microscopy (ETEM) was used to follow the visual changes. We reveal that the reduction of monoclinic MoO3 to cubic oxygen-deficient Mo oxide (MoOx) at low temperatures owing to the promoted H2 activation on Rh sites is vital to the following carbon atom insertion and transformation to α-MoC1-x, making the carburization follow the topological route. The systematic analysis of the relationship between the reduction behavior and the structural evolution supplies a feasible strategy for the α-MoC1-x synthesis, and in situ characterizations shed light on controlling the phase transformation during carburization.

Shear stress regulates the SNAP23-mediated endothelial secretion of VWF through the GPR68/PKA/vimentin mechanotransduction pathway.

Von Willebrand Factor (VWF) can promote platelet adhesion to the post-atherosclerotic regions to initiate thrombosis. The synthesis and secretion of VWF are important functions of endothelial cells (ECs). However, the mechanism through which blood flow regulates endothelial secretion of VWF remains unclear. We utilized a parallel-plate flow apparatus to apply fluid shear stress to human umbilical vein endothelial cells (HUVECs). Compared with pulsatile shear stress that mimics laminar flow in the straight parts of arteries or upstream of atherosclerotic stenosis sites, short-term exposure to oscillatory shear stress (OS) that mimics disturbed flow increased VWF secretion independent of affecting synaptosomal-associated protein 23 (SNAP23) expression and promoted the translocation of SNAP23 to the cell membrane. Vimentin associated with SNAP23, and this association was enhanced by OS or histamine. Acrylamide, a reagent that disrupts vimentin intermediate filaments, prevented histamine/OS-induced SNAP23 translocation, as well as VWF secretion. Immunofluorescence analysis revealed that the polarity of the vimentin intermediate filament network decreased after stimulation with histamine or OS. In addition, inhibition of protein kinase A (PKA) or G protein coupled receptor 68 (GPR68) eliminated the histamine/OS-induced phosphorylation of vimentin at Ser38 and secretion of VWF. Furthermore, syntaxin 7 might assist with the translocation of SNAP23 to the cell membrane, thus playing a role in promoting VWF secretion. The GPR68/PKA/vimentin signaling pathway may represent a novel mechanism for the regulation of SNAP23-mediated VWF secretion by ECs under OS and provide strategies for the prevention of atherosclerosis-related thrombosis.

Efficient all-inorganic red perovskite light-emitting diodes with dual-interface-modified perovskites by vapor deposition.

Interface engineering has been extensively used in perovskite light-emitting diodes (PeLEDs), which proves to be an effective and intelligent approach for surface defect passivation. However, the existing passivation strategy is restricted to the solution process, which results in poor compatibility with vapor-deposited PeLEDs and moderate controllability. Here, we propose a dual-interface modification strategy to facilitate the performance improvement of vapor-deposited all-inorganic red PeLEDs. An ultrathin phenylethanamine bromide (PEABr) layer is introduced to both the upper and lower interfaces of the vapor-deposited perovskite emission layer by vapor deposition. The vapor deposition of the PEABr with fine-controlled film thickness is a reliable and simple process and compatible with vapor-deposited all-inorganic PeLEDs. The dual-interface modification plays an observable role in manipulating the crystallization and surface morphology of the CsPbBrI2 film, which is of significance for the improvement of the PeLEDs' performance. As a result, the red PeLEDs achieve a maximum luminance and external quantum efficiency of 2338 cd/m2 and 1.75%, corresponding to enhancements of 2.75 and 5.25 times compared with those of PeLEDs without PEABr. This approach paves the way to high-efficiency all-evaporated all-inorganic PeLEDs.

Integratable photodetectors based on photopolymerized conductive polymer via femtosecond laser direct writing.

Conductive polymers have attracted a great deal of attention due to their remarkable electrical conductivity. However, the low solubility and inability to meet the limit for the flexible patterning fabrication ability of conductive polymers hinders their applications in miniaturized and integrated electronic devices. Here, femtosecond laser direct writing (FsLDW) is employed to achieve the in situ fabrication of polypyrrole (PPy) with flexibility. Notably, high-precision flexible patterning with a minimum feature size of 5.2 µm and spatial control over the polymerization of PPy is achieved. Moreover, PPy microwires are constructed into a photodetector that exhibits a responsivity of 644 A/W at 0.1-V bias under ultraviolet (UV) irradiation. Ultimately, an image sensor is fabricated by integrating multiple photodetectors, demonstrating the application potential of FsLDW technology for developing miniaturized and integrated electronic devices based on conductive polymers.

Nucleation in situ of perylene crystal by femtosecond laser induced cavitation.

Organic semiconductor single crystal materials have broad application prospects in the field of high-performance optoelectronic devices because of their highly ordered structure, few defects, and high carrier mobility. However, it is difficult to control the nucleation location of crystal formation in the current commonly used crystal growth methods including physical vapor transport and solution processing, which makes it difficult to manufacture organic crystal devices. Laser-induced crystallization technology is expected to solve this problem. In this study, we demonstrated nucleation in situ of a perylene crystal by femtosecond laser induced cavitation. The results show that the crystallization of perylene crystals induced by the femtosecond laser is mainly due to the aggregation effect by laser cavitation bubbles caused by multiphoton absorption. This strategy facilitates the application of organic single crystals to optoelectronic devices.

Spatially modulated light harvesting with plasmonic crescent metasurface.

Harvesting light by metallic structures with sharp corners, or the so-called photonic singularities, has exhibit their potential in nanophotonics, sensing, and bio-medical applications. The high-quality light confinement of the light energy mainly relies on the precise preparation of nanoscale photonic singularities. However, the realization of massive photonic singularities still meets the challenges on integration and low-cost mask multiplexing. Here, we show an angle-dependent elevated nanosphere lithography to achieve massive photonic singularities for spatially modulated light harvesting at the near-infrared regime. The photonic geometrical singularity is constructed by the gold crescent array of plasmonic materials. The numerical simulation shows that the light can be localized at the spatially distributed singularities. This phenomenon is verified experimentally through the infrared spectral measurement. Our work provides the possibility to produce integrated light-harvesting devices for numerous optical applications in illumination, display, and enhanced nonlinear excitation.

Efficient and stretchable organic light-emitting devices based on spontaneously formed disordered wrinkles.

We propose a facile, scalable strategy to introduce spontaneously formed disordered wrinkles into organic light-emitting devices (OLEDs) to enhance light extraction and realize stretchability of the devices. The luminance and current efficiency of the wrinkled OLEDs are improved by 37% and 18%, respectively, compared to the planar device. Meanwhile, broadband light scattering induced by the disordered wrinkles results in angle-stable electroluminescent spectra at wide viewing angles for the wrinkled OLEDs. The disordered wrinkles enable the OLEDs to be stretchable and withstand hundreds of stretching-releasing cycles at strain between 0% and 5%. This study provides a simple method to realize stretchable OLEDs with high efficiency.

Dynamic Behavior of Single-Atom Catalysts in Electrocatalysis: Identification of Cu-N3 as an Active Site for the Oxygen Reduction Reaction.

Atomically dispersed M-N-C (M refers to transition metals) materials represent the most promising catalyst alternatives to the precious metal Pt for the electrochemical reduction of oxygen (ORR), yet the genuine active sites in M-N-C remain elusive. Here, we develop a two-step approach to fabricate Cu-N-C single-atom catalysts with a uniform and well-defined Cu2+-N4 structure that exhibits comparable activity and superior durability in comparison to Pt/C. By combining operando X-ray absorption spectroscopy with theoretical calculations, we unambiguously identify the dynamic evolution of Cu-N4 to Cu-N3 and further to HO-Cu-N2 under ORR working conditions, which concurrently occurs with reduction of Cu2+ to Cu+ and is driven by the applied potential. The increase in the Cu+/Cu2+ ratio with the reduced potential indicates that the low-coordinated Cu+-N3 is the real active site, which is further supported by DFT calculations showing the lower free energy in each elemental step of the ORR on Cu+-N3 than on Cu2+-N4. These findings provide a new understanding of the dynamic electrochemistry on M-N-C catalysts and may guide the design of more efficient low-cost catalysts.