RESUMO
Designing a reasonable heterojunction is an efficient path to improve the separation of photogenerated charges and enhance photocatalytic activity. In this study, Cu2-xS@NiFe-LDH hollow nanoboxes with core-shell structure are successfully prepared. The results show that Cu2-xS@NiFe-LDH with broad-spectrum response has good photothermal and photocatalytic activity, and the photocatalytic activity and stability of the catalyst are enhanced by the establishment of unique hollow structure and core-shell heterojunction structure. Transient PL spectra (TRPL) indicates that constructing Cu2-xS@NiFe-LDH heterojunction can prolong carrier lifetime obviously. Cu2-xS@NiFe-LDH shows a high photocatalytic hydrogen production efficiency (5176.93 µmol h-1 g-1), and tetracycline degradation efficiency (98.3%), and its hydrogen production rate is ≈10-12 times that of pure Cu2-xS and NiFe-LDH. In situ X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) provide proofs of the S-scheme electron transfer path. The S-scheme heterojunction achieves high spatial charge separation and exhibits strong photoredox ability, thus improving the photocatalytic performance.
RESUMO
Laser-induced breakdown spectroscopy (LIBS), as an elemental composition analysis technique, has many unique advantages and great potential for applications in water detection. However, the quality of LIBS spectral signals, such as signal-to-noise ratio and stability, is often poor due to the matrix effects of water, limiting its practical performance. To effectively remove the inherent weak radiation in experimental spectral data that can be easily mistaken for noise, this paper proposes a denoising algorithm for processing spectral data using a self-built blank sample spectral database of deionized water samples, and designs a complete data processing workflow. It includes steps such as blank sample data screening, internal standard correction, blank sample correction, and spectral smoothing. Against the backdrop of marine applications, experimental spectral data for target elements Na, Mg, Ca, K, Sr, and Li were processed with this algorithm. The results show that after algorithm processing, the spectral quality was significantly improved, with the signal-to-noise ratio and detection limits of various elements improved by at least one order of magnitude. The signal-for Li increased by up to 36 times, and the detection limit for K decreased by up to 25.2 times. Additionally, tiny spectral peaks that could not be observable in the original spectral data could be effectively extracted after processing. From a technical implementation perspective, the database establishment and data process are simple and practical, with universal applicability. Therefore, this method has good potential and wide foregrounds in many other water sample LIBS detection technologies.
RESUMO
AIMS: Elucidating the impacts of long-term spaceflight on cardiovascular health is urgently needed in face of the rapid development of human space exploration. Recent reports including the NASA Twins Study on vascular deconditioning and aging of astronauts in spaceflight are controversial. The aims of this study were to elucidate whether long-term microgravity promotes vascular aging and the underlying mechanisms. METHODS AND RESULTS: Hindlimb unloading (HU) by tail suspension was used to simulate microgravity in rats and mice. The dynamic changes of carotid stiffness in rats during 8 weeks of HU were determined. Simulated microgravity led to carotid artery aging-like changes as evidenced by increased stiffness, thickness, fibrosis, and elevated senescence biomarkers in the HU rats. Specific deletion of the mechanotransducer Piezo1 in vascular smooth muscles significantly blunted these aging-like changes in mice. Mechanistically, mechanical stretch-induced activation of Piezo1 elevated microRNA-582-5p in vascular smooth muscle cells, with resultant enhanced synthetic cell phenotype and increased collagen deposition via PTEN/PI3K/Akt signalling. Importantly, inhibition of miRNA-582-5p alleviated carotid fibrosis and stiffness not only in HU rats but also in aged rats. CONCLUSIONS: Long-term simulated microgravity induces carotid aging-like changes via the mechanotransducer Piezo1-initiated and miRNA-mediated mechanism.
Assuntos
Artérias Carótidas , Canais Iônicos , Mecanotransdução Celular , MicroRNAs , Músculo Liso Vascular , Miócitos de Músculo Liso , Rigidez Vascular , Simulação de Ausência de Peso , Animais , Envelhecimento/metabolismo , Envelhecimento/patologia , Artérias Carótidas/metabolismo , Artérias Carótidas/patologia , Artérias Carótidas/fisiopatologia , Células Cultivadas , Modelos Animais de Doenças , Fibrose , Elevação dos Membros Posteriores , Canais Iônicos/metabolismo , Canais Iônicos/genética , Mecanotransdução Celular/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/metabolismo , MicroRNAs/genética , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Músculo Liso Vascular/fisiopatologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Fenótipo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , PTEN Fosfo-Hidrolase/genética , Ratos Sprague-Dawley , Transdução de Sinais , Fatores de Tempo , Remodelação VascularRESUMO
Cyclosporine A (CsA) is a secondary cyclopeptide metabolite produced by Tolypocladium inflatum that is widely used clinically as an immunosuppressant. CsA production and mycelial growth differed when T. inflatum was cultured in different carbon source media. During early fermentation, CsA was preferred to be produced in fructose medium, while the mycelium preferred to accumulate in sucrose medium. On the sixth day, the difference was most pronounced. In this study, high-throughput comparative proteomics methods were applied to analyze differences in protein expression of mycelial samples on day 6, revealing the proteins and mechanisms that positively regulate CsA production related to carbon metabolism. The differences included small molecule acid metabolism, lipid metabolism, organic catabolism, exocrine secretion, CsA substrate Bmt synthesis, and transcriptional regulation processes. The proteins involved in the regulation of mycelial growth related to carbon metabolism were also revealed and were associated with waste reoxidation processes or coenzyme metabolism, small molecule synthesis or metabolism, the stress response, genetic information or epigenetic changes, cell component assembly, cell wall integrity, membrane metabolism, vesicle transport, intramembrane localization, and the regulation of filamentous growth. This study provides a reliable reference for CsA production from high-efficiency fermentation. This study provides key information for obtaining more CsA high-yielding strains through metabolic engineering strategies.