Search

Objectives: The main objective of this study was to establish a mouse model of spinal ligament ossification to simulate the chronic spinal cord compression observed in patients with ossification of the posterior longitudinal ligament (OPLL). The study also aimed to examine the mice's neurobiological, radiological, and pathological changes. Methods: In the previous study, a genetically modified mouse strain was created using Crispr‐Cas9 technology, namely, Enpp1flox/flox/EIIa‐Cre (C57/B6 background), to establish the OPLL model. Wild‐type (WT) mice without compression were used as controls. Functional deficits were evaluated through motor score assessment, inclined plate testing, and gait analysis. The extent of compression was determined using CT imaging. Hematoxylin and eosin staining, luxol fast blue staining, TUNEL assay, immunofluorescence staining, qPCR, and Western blotting were performed to evaluate levels of apoptosis, inflammation, vascularization, and demyelination in the study. Results: The results demonstrated a gradual deterioration of compression in the Enpp1flox/flox/EIIa‐Cre mice group as they aged. The progression rate was more rapid between 12 and 20 weeks, followed by a gradual stabilization between 20 and 28 weeks. The scores for spinal cord function and strength, assessed using the Basso Mouse Scale and inclined plate test, showed a significant decline. Gait analysis revealed a noticeable reduction in fore and hind stride lengths, stride width, and toe spread. Chronic spinal cord compression resulted in neuronal damage and activated astrocytes and microglia in the gray matter and anterior horn. Progressive posterior cervical compression impeded blood supply, leading to inflammation and Fas‐mediated neuronal apoptosis. The activation of Bcl2 and Caspase 3 was associated with the development of progressive neurological deficits (p < 0.05). Conclusions: The study presents a validated model of chronic spinal cord compression, enabling researchers to explore clinically relevant therapeutic approaches for OPLL. [ABSTRACT FROM AUTHOR]

Recently, the application of two–dimensional (2D) piezoelectric materials has been seriously hindered because most of them possess only in–plane piezoelectricity but lack out–of–plane piezoelectricity. In this work, using first–principles calculation, by atomic substitution of penta–graphene (PG) with tiny out–of–plane piezoelectricity, we design and predict stable 2D X–PG (X = Si or Ge) semiconductors with excellent in–plane and out–of–plane piezoelectricity and extremely high in–plane hole mobility. Among them, Ge–PG exhibits better performance in all aspects with an in–plane strain piezoelectric coefficient d11 = 8.43 pm/V, an out–of–plane strain piezoelectric coefficient d33 = −3.63 pm/V, and in–plane hole mobility μh = 57.33 × 103 cm2 V−1 s−1. By doping Si and Ge atoms, the negative Poisson's ratio of PG approaches zero and reaches a positive value, which is due to the gradual weakening of the structure's mechanical strength. The bandgaps of Si–PG (0.78 eV) and Ge–PG (0.89 eV) are much smaller than that of PG (2.20 eV), by 2.82 and 2.47 times, respectively. This indicates that the substitution of X atoms can regulate the bandgap of PG. Importantly, the physical mechanism of the out–of–plane piezoelectricity of these monolayers is revealed. The super–dipole–moment effect proposed in the previous work is proved to exist in PG and X–PG, i.e., it is proved that their out–of–plane piezoelectric stress coefficient e33 increases with the super–dipole–moment. The e33–induced polarization direction is also consistent with the super–dipole–moment direction. X–PG is predicted to have prominent potential for nanodevices applied as electromechanical coupling systems: wearable, ultra–thin devices; high–speed electronic transmission devices; and so on. [ABSTRACT FROM AUTHOR]

Hybrid tin halides with formamidinium cations become a promising candidate for eco‐friendly solar cells, which achieves the best photovoltaic performance among various lead‐free perovskite solar cells (PSCs). Unfortunately, the low quality of perovskite layers and the oxidation of Sn2+ ions degrade the performance of devices, leading to an obviously lower power conversion efficiency (PCE) compare to hybrid lead halides. Additive engineering is a facile strategy for improving the quality of perovskite layers. In this work, the 2‐aminopyrazine (APZ) additive is investigated for depositing FA0.8PEA0.2SnI2.8Br0.2 layers, and corresponding PSCs are examined. It is found that the melting point of APZ additives drops below the annealing temperature of perovskite layers by the intermolecular interaction with formamidinium iodide (FAI). The melt phase at the grain boundaries encourages the diffusion of ions in the annealing process, leading to an improved quality of perovskite layers. And the formation of APZ‐SnI2 complex also inhibits the oxidation of Sn2+ ions. Consequently, the defect density and the recombination are significantly reduced in PSCs, resulting in an increase of PCEs from 11.4% to 13.0% and a simultaneous improvement of device stability. This work demonstrates a strategy for improving tin‐based PSCs based on melt assisted annealing and coordination interaction. [ABSTRACT FROM AUTHOR]

The hole transport layers are critical for collecting holes and suppressing recombination in perovskite solar cells, and metal oxides are superior due to their green synthesis and good ambient stability. Although gallium oxide is rarely applied as the hole transport layers of devices for the mismatch of valence bands with perovskite materials, copper dopants can provide an additional transport channel via their impurity levels. Herein, InxGa2−xO3 nanocrystals with copper dopants are synthesized as the hole transport material of perovskite solar cells by the hydrothermal method, and uniform hole transport layers can be deposited by spin‐coating at a low temperature of 100 °C. The energy position of impurity levels and the hole transport ability of hole transport layers can be regulated by incorporating indium ions. In the optimized condition, the efficiencies of devices increase from 19.6% to 21.4%, which is related to the improvement of the charge extraction process and carrier recombination process. And the photostability of devices can be improved simultaneously. This work provides an efficient hole transport material for inverted perovskite solar cells and demonstrates the regulation of transport channels via impurity levels. [ABSTRACT FROM AUTHOR]