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Background: We systematically reviewed and analyzed the efficacy and safety of insulin degludec/insulin as-part (IDegAsp) versus biphasic insulin aspart 30 (BIAsp 30) in patients with type 2 diabetes (T2D). Methods: We used computers to search the Embase, PubMed, Clinical Trials, and the Cochrane Library database, and collected randomized controlled trials (RCTs) on the treatment of IDegAsp versus BIAsp 30 in T2D patients. The research period was from the establishment of the database to May 19, 2023. We used Review Manager 5.20 statistical software for systematic meta-analysis. Results: We included 8 RCTs with 2281 participants. IDegAsp was better to BIAsp30 in improving fasting plasma glucose (FPG) levels (P<0.001) and reducing the endpoint daily average insulin dose (P<0.01). Furthermore, compared with BIAsp30, IDegAsp significantly reduced the risk of nocturnal hypoglycemic events (P<0.001). However, there was no significant difference in the improvement of body weight change (P=0.99), glycosylated hemoglobin (P=0.50), the overall risk of hypoglycemic events (P=0.57) and adverse events (P=0.89) between the two groups. Conclusion: Compared with BIAsp30, IDegAsp could significantly reduce FPG levels, insulin dosage, and the risk of nocturnal hypoglycemic events in T2D patients, without increasing the overall risk of adverse events.
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Vanadium-based compounds are fantastic cathodes for aqueous zinc metal batteries due to the high specific capacity and excellent rate capability. Nevertheless, the practical application has been hampered by the dissolution of vanadium in traditional aqueous electrolytes owing to the strong polarity of water molecules. Herein, we propose a hybrid electrolyte made of Zn(ClO4)2 salt in tetraethylene glycol dimethyl ether (G4) and H2O solvents to upgrade the cycle life of Zn//K0.486V2O5 battery. The G4 jointly solvates with Zn2+ ions and replaces a portion of the H2O molecules in the Zn2+ solvation sheath. It forms a strong bond with H2O, reducing its activity, and significantly inhibiting vanadium dissolution and water-induced parasitic reaction. Consequently, the optimized electrolyte with H2O and G4 volume ratio of 5 : 5 enhances the cycling stability of Zn//K0.486V2O5 battery, enabling it to reach up to 600 cycles. In addition, the battery demonstrates a satisfactory reversible capacity of 475.7â mAh g-1 and excellent rate performance attributed to the moderate ionic conductivity (28.8â mS cm-1) of the hybrid electrolyte. Last but not least, in the optimized electrolyte, the symmetric Zn//Zn cells deliver a long cycling performance of 400â h, while the asymmetric Zn//Cu cells shows a high average coulombic efficiency of 97.4 %.
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Gestational diabetes mellitus (GDM) is a common metabolic condition during pregnancy, posing risks to both mother and fetus. CircRNAs have emerged as important players in various diseases, including GDM. We aimed to investigate the role of newly discovered circRNA, hsa_circ_0042260, in GDM pathogenesis. Using GSE194119 dataset, hsa_circ_0042260 was identified and its expression in plasma, placenta, and HG-stimulated HK-2 cells was examined. Silencing hsa_circ_0042260 in HK-2 cells assessed its impact on cell viability, apoptosis, and inflammation. Bioinformatics analysis revealed downstream targets of hsa_circ_0042260, namely miR-4782-3p and LAPTM4A. The interaction between hsa_circ_0042260, miR-4782-3p, and LAPTM4A was validated through various assays. hsa_circ_0042260 was upregulated in plasma from GDM patients and HG-stimulated HK-2 cells. Silencing hsa_circ_0042260 improved cell viability, suppressed apoptosis and inflammation. Hsa_circ_0042260 interacted with miR-4782-3p, which exhibited low expression in GDM patient plasma and HG-stimulated cells. MiR-4782-3p targeted LAPTM4A, confirmed by additional assays. LAPTM4A expression increased in GDM patient plasma and HG-induced HK-2 cells following hsa_circ_0042260 knockdown or miR-4782-3p overexpression. In rescue assays, inhibition of miR-4782-3p or overexpression of LAPTM4A counteracted the effects of hsa_circ_0042260 downregulation on cell viability, apoptosis, and inflammation. In conclusion, the hsa_circ_0042260/miR-4782-3p/LAPTM4A axis plays a role in regulating GDM progression in HG-stimulated HK-2 cells.
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Apoptose , Diabetes Gestacional , MicroRNAs , RNA Circular , Adulto , Feminino , Humanos , Gravidez , Apoptose/genética , Linhagem Celular , Sobrevivência Celular/genética , Diabetes Gestacional/metabolismo , Diabetes Gestacional/genética , Diabetes Gestacional/patologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Placenta/metabolismo , Placenta/patologia , RNA Circular/genéticaRESUMO
Designing bifunctional electrocatalysts with outstanding reactivity and durability towards the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has remained a long-term aim for metal-air batteries. Achieving the high level of fusion between two distinct metal components to form bifunctional catalysts with optimized heterointerfaces and well-defined morphology holds noteworthy implications in the enhancement of electrocatalytic activity yet challenging. Herein, the fabrication of numerous heterointerfaces of CoN/MnO is successfully realized within ultrathin carbon nanosheets via a feasible self-templating synthesis strategy. Experimental results and theoretic calculations verify that the interfacial electron transfer from CoN to MnO at the heterointerface engenders an ameliorated charge transfer velocity, finely tuned energy barriers concerning reaction intermediates and ultimately accelerated reaction kinetics. The as-prepared CoN/MnO@NC demonstrates exceptional bifunctional catalytic performance, excelling in both OER and ORR showcasing a low reversible overpotential of 0.69 V. Furthermore, rechargeable liquid and quasi-solid-state flexible Zn-air batteries employing CoN/MnO@NC as the air-cathode deliver remarkable endurance and elevated power density, registering values of 153 and 116 mW cm-2 respectively and exceeding Pt/C + RuO2 counterparts and those reported in literature. Deeply exploring the effect of electron-accumulated heterointerfaces on catalytic activity would contribute wisdom to the development of bifunctional electrocatalysts for rechargeable metal-air batteries.
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Pseudouridine is one of the well-known chemical modifications in various RNA species. Current advances to detect pseudouridine show that the pseudouridine landscape is dynamic and affects multiple cellular processes. Although our understanding of this post-transcriptional modification mainly depends on yeast and human models, the recent findings provide strong evidence for the critical role of pseudouridine in plants. Here, we review the current knowledge of pseudouridine in plant RNAs, including its synthesis, degradation, regulatory mechanisms, and functions. Moreover, we propose future areas of research on pseudouridine modification in plants.
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Pseudouridina , RNA , Humanos , Pseudouridina/metabolismo , RNA/genética , RNA/metabolismo , Processamento Pós-Transcricional do RNA , RNA de Plantas/genética , RNA de Plantas/metabolismo , Saccharomyces cerevisiae/genética , RNA Ribossômico/metabolismoRESUMO
The unique dumbbell-shape of grass guard cells (GCs) is controlled by their cell walls which enable their rapid responses to the environment. The molecular mechanisms regulating the synthesis and assembly of GC walls are as yet unknown. Here we have identified BZU3, a maize gene encoding UDP-glucose 4-epimerase that regulates the supply of UDP-glucose during GC wall synthesis. The BZU3 mutation leads to significant decreases in cellular UDP-glucose levels. Immunofluorescence intensities reporting levels of cellulose and mixed-linkage glucans are reduced in the GCs, resulting in impaired local wall thickening. BZU3 also catalyzes the epimerization of UDP-N-acetylgalactosamine to UDP-N-acetylglucosamine, and the BZU3 mutation affects N-glycosylation of proteins that may be involved in cell wall synthesis and signaling. Our results suggest that the spatiotemporal modulation of BZU3 plays a dual role in controlling cell wall synthesis and glycosylation via controlling UDP-glucose/N-acetylglucosamine homeostasis during stomatal morphogenesis. These findings provide insights into the mechanisms controlling formation of the unique morphology of grass stomata.
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Racemases e Epimerases , Zea mays , Zea mays/genética , Zea mays/metabolismo , Racemases e Epimerases/metabolismo , Glicosilação , Acetilglucosamina/metabolismo , Poaceae/metabolismo , Parede Celular/metabolismo , Difosfato de Uridina/metabolismoRESUMO
Purpose: The purpose of this study was to evaluate the ability of metagenomic next-generation sequencing (mNGS) diagnosing prosthetic joint infection (PJI) using tissue from hip/knee rapidly and precisely, especially in patients who had received antibiotic treatment within the preceding two weeks. Methods: From May 2020 to March 2022, 52 cases with suspected PJI were enrolled. mNGS was performed on surgical tissue samples. The sensitivity and specificity of mNGS in diagnosis was evaluated using culture in conjunction with MSIS criteria. This study also looked at how antibiotic use affected culture and mNGS efficacy. Results: According to MSIS criteria, 31 of the 44 cases had PJI, and 13 were classified in the aseptic loosening group. Sensitivity, specificity, positive/negative predictive value (PPV/NPV), positive/negative likelihood ratio (PLR/NLR), and area under the curve (AUC) of mNGS assay were 80.6% (71.9-91.8%), 84.6 (73.7-97.9%), 92.6 (84.2-98.7%), 64.7 (58.6-74.7%), 5.241 (4.081-6.693), 0.229 (0.108-0.482) and 0.826 (0.786-0.967), respectively, with MSIS as a reference. When MSIS was used as a reference, the results of culture assay were 45.2% (40.8-51.5%), 100 (100.0-100.0%), 100 (100.0-100.0%), 43.3 (39.1-49.5%), +∞, 0.548 (0.396-0.617) and 0.726 (0.621-0.864), respectively. The AUC values for mNGS and culture were 0.826 and 0.731, respectively, and the differences were insignificant. mNGS demonstrated higher sensitivity than culture in PJI subjects who had previously received antibiotic treatment within 2 weeks (69.5% vs 23.1%, P = 0.03). Conclusion: In our series, mNGS yield a higher sensitivity for diagnosis and pathogen detection of PJI compared to microbiological culture. Additionally, mNGS is less affected by prior antibiotic exposure.
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Background: Intracystic hemorrhage from lymphangiomas is a common phenomenon in lymphatic malformations (LMs); however, little is known about the associated compositional changes in the lymphatic fluid. Materials and Methods: We prospectively collected lymphatic fluid from children with LMs. Lymphatic fluid was divided depending on the bleeding status into the bleeding and nonbleeding groups. The fluid was subjected to cytological and biochemical analyses to determine protein and cytokine levels. The Mann-Whitney U test was used to compare the two groups. Results: There were significant differences in the levels of interleukin (IL)-6, IL-10, and glucose, and the percentage of white blood cells between the bleeding and nonbleeding groups. There was no significant difference in chlorine and protein content; white blood cell count; and IL-2, IL-4, tumor necrosis factor α, and interferon γ levels between the two groups. Conclusion: Lymphatic fluid is less stable in bleeding LMs than in non-bleeding LMs and is prone to inflammatory reactions. The inflammatory reaction in lymphatic fluid does not stimulate the cytokine storm in blood. The inflammatory reaction due to LMs does not affect the contents of protein and chlorine in lymphatic cyst fluid.
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Anormalidades Linfáticas , Vasos Linfáticos , Criança , Humanos , Cloro , Citocinas/metabolismo , Vasos Linfáticos/metabolismo , Interleucina-6/metabolismo , Anormalidades Linfáticas/diagnóstico , InflamaçãoRESUMO
Photoreduction of CO2 is a promising strategy to synthesize value-added fuels or chemicals and realize carbon neutralization. Noncopper catalysts are seldom reported to generate C2 products, and the selectivity over these catalysts is low. Here, we design rich-interface, heterostructured In2O3/InP (r-In2O3/InP) for highly competitive photocatalytic CO2-to-CH3COOH conversion with a productivity of 96.7 µmol g-1 and selectivity > 96% along with water oxidation to O2 in pure water (no sacrificial agent) under visible light irradiation. The hard X-ray absorption near-edge structure (XANES) shows that the formation of r-In2O3/InP with the isogenesis cation adjusts the coordination environment via interface engineering and forms O-In-P polarized sites at the interface. In situ FT-IR and Raman spectra identify the key intermediates of OCCO* for acetate production with high selectivity. Density functional theory (DFT) calculations reveal that r-In2O3/InP with rich O-In-P polarized sites promotes C-C coupling to form C2 products because of the imbalanced adsorption energies of two carbon atoms. This work reports an interesting indium-based photocatalyst for selective CO2 photoreduction to acetate under strict solution and irradiation conditions and provides significant insights into fabricating interfacial polarization sites to promote the process.
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Background: Dexmedetomidine (Dex), as a new and highly selective α2 adrenergic receptor agonist, has been widely used in mechanically ventilated patients. In the present study, we used meta-analysis to study the effect of Dex on the prognosis of mechanically ventilated patients with sepsis. Methods: We searched PubMed, Cochrane clinical trial, EMBASE, Web of Science, and Chinese biomedical literature database to analyze relevant literature published from January 2000 to January 2021. We conducted the quality evaluation and data extraction for studies that met the inclusion criteria. RevMan 5.3 software was used to perform a meta-analysis of the 28-day mortality, hospital mortality, the length of ICU stay, and other adverse indicators. Results: Ten randomized controlled trials (RCTs) that met the inclusion criteria were finally included, including 9 RCTs in English and one in Chinese, with a total of 892 patients. Our meta-analysis results found that in mechanically ventilated patients with sepsis, Dex could significantly reduce the length of ICU stay (P=0.02), but did not reduce the patients' 28-day mortality (P=0.06), hospital mortality (P=0.17) and ventilator-free days (P=0.33). Furthermore, our meta-analysis results also found that Dex had no significant effect on the respiratory rate (P=0.53), heart rate (P=0.02), mean arterial pressure (P=0.63), the level of creatinine (P=0.82) and continuous renal replacement therapy (P=0.39) in mechanically ventilated patients with sepsis. Conclusion: In mechanically ventilated patients with sepsis, Dex can reduce the length of ICU stay, but which cannot reduce the 28-day mortality, hospital mortality, and ventilator-free days.
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Kaposiform hemangioendothelioma (KHE) is a rare vascular neoplasm associated with the Kasabach-Merritt phenomenon (KMP), which is a consumptive coagulopathy with associated potentially life-threatening thrombocytopenia. There are no standardized treatment protocols for the management of KHE with KMP. Moreover, there are limited reports regarding the treatment of cases of rebound. Herein, we describe a rare case of rebound of KHE/KMP, during systemic sirolimus treatment, successfully treated with embolization and vincristine infusion combined with microwave ablation.
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Purpose: The discrimination of prosthetic joint infection (PJI) from aseptic failure is regarded as a major clinical challenge. The key function of human neutrophil lipocalin (HNL) in regulating bacterial infection rationalizes its potential as a biomarker to diagnose PJI. This work evaluated the accuracy of serum human neutrophil lipocalin as a biomarker to diagnose PJI. Methods: This prospective cohort study enrolled altogether 58 patients suffering from miserable knee or hip arthroplasty and receiving revision surgery from 2018 to 2020. Related laboratory and clinical information of these patients were retrieved. Following the Musculoskeletal Infection Society (MSIS) criteria, the diagnosis of PJI was conducted. Collecting preoperative blood samples, we measured HNL by the standard assay. Thereafter, plotting the receiver-operating characteristic curve (ROC), the area under the curve (AUC) values were calculated to analyze the diagnosis accuracy. Results: According to the MSIS criteria, 38 cases (65.5%) were classified into the PJI group, while 20 (34.5%) into the aseptic loosening group, with age ranging from 38 to 87 (median, 66.9) years. The median serum HNL level of the PJI patients was 199.01 (range, 85.34-357.79) ng/mL, significantly higher as compared with that of 64.81 (range, 20.73-157.89) ng/mL of the aseptic loosening group. Using the Youden index, the optimal threshold value was 105.1ng/mL, while the specificity, sensitivity, and AUC were 85.0%, 81.6%, and 0.919, respectively. Conclusion: Serum HNL is the creditable test that can be employed as the laboratory biomarker to screen PJI. The threshold HNL level is 105.1 ng/mL, which may distinguish PJI from aseptic failure.
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As the most abundant RNA modification, pseudouridylation has been shown to play critical roles in Escherichia coli, yeast and humans. However, its function in plants is still unclear. Here, we characterized leaf curly and small 1 (FCS1), which encodes a pseudouridine synthase in Arabidopsis. fcs1 mutants exhibited severe defects in plant growth, such as delayed development and reduced fertility, and were significantly smaller than the wild type at different developmental stages. FCS1 protein is localized in the mitochondrion. The absence of FCS1 significantly reduces pseudouridylation of mitochondrial 26S ribosomal RNA (rRNA) at the U1692 site, which sits in the peptidyl transferase center. This affection of mitochondrial 26S rRNA may lead to the disruption of mitochondrial translation in the fcs1-1 mutant, causing high accumulation of transcripts but low production of proteins. Dysfunctional mitochondria with abnormal structures were also observed in the fcs1-1 mutant. Overall, our results suggest that FCS1-mediated pseudouridylation of mitochondrial 26S rRNA is required for mitochondrial translation, which is critical for maintaining mitochondrial function and plant development.
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Arabidopsis , Transferases Intramoleculares , Mitocôndrias , Desenvolvimento Vegetal , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Transferases Intramoleculares/metabolismo , Mitocôndrias/enzimologia , Pseudouridina/química , Pseudouridina/metabolismo , RNA Mitocondrial/genética , RNA Mitocondrial/metabolismo , RNA Ribossômico/química , RNA Ribossômico/genética , RNA Ribossômico/metabolismoRESUMO
Exploring bifunctional oxygen electrocatalysts with low cost and high performance is critical to the development of rechargeable zinc-air batteries, but it still remains a huge challenge. In this work, a "coordination construction-pyrolysis/self-catalyzed growth" approach was employed to fabricate branches@trunks-like, N-doped carbon nanotubes@nanowires superstructure with uniformly incorporated CoFe alloy nanoparticles (CoFe@CNTs-NWs). The rational design of such hierarchical architecture could effectively enlarge the exposure of active sites, modulate their electronic structure, and assist the electron transfer and mass diffusion, thus benefiting both ORR and OER. The resultant CoFe@CNTs-NWs displayed prominent bifunctional electrocatalytic activity and stability with a minimized oxygen overpotential of 0.71â V. When used as a cathode for zinc-air batteries, it provided a high peak power density of 131â mW cm-2 and remarkable charge-discharge stability for at least 400â cycles (130â h). This study presents a successful demonstration for optimizing the electrocatalytic performance by elaborate nanostructure and carbon matrix hybridization with simultaneous modulation of electronic structure, thus providing a new avenue to the rational design of transition metal-based oxygen electrocatalysts.
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Aim: To evaluate the correlation of long noncoding RNAs (lncRNAs) expression in circulating exosomes and the cancerous and noncancerous tissues in patients with non-small-cell lung carcinoma. Methods: The relative expression of the four lncRNAs including LUADT1, MALAT1, NEAT1 and MIAT between tumor tissue, adjacent noncancerous tissues and circulating exosomes were evaluated by quantitative reverse transcription PCR. Results & conclusion: The relative expression of the lncRNAs, including LUADT1, MALAT1 and NEAT1, was upregulated and MIAT was downregulated in tumor tissue compared with noncancerous tissue samples. The expression of lncRNAs in circulating exosomes was not significantly different from cancerous tissue. Our results indicate that the studied exosomal lncRNAs have a good potential to be further evaluated as prognostic/diagnostic biomarkers in patients with non-small-cell lung cancer.
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Carcinoma Pulmonar de Células não Pequenas , Exossomos , Neoplasias Pulmonares , RNA Longo não Codificante , Carcinogênese , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Exossomos/metabolismo , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Prognóstico , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
The transcription factor ABSCISIC ACID INSENSITIVE5 (ABI5) plays a crucial role in abscisic acid (ABA) signaling during seed germination. However, how ABI5 is regulated during this process is poorly understood. Here, we report that the ubiquitin E3 ligase MIEL1 and its target transcription factor MYB30 modulate ABA responses in Arabidopsis thaliana during seed germination and seedling establishment via the precise regulation of ABI5. MIEL1 interacts with and ubiquitinates ABI5 to facilitate its degradation during germination. The transcription factor MYB30, whose turnover is mediated by MIEL1 during seed germination, also interacts with ABI5 to interfere with its transcriptional activity. MYB30 functions downstream of MIEL1 in the ABA response, and both are epistatic to ABI5 in ABA-mediated inhibition of seed germination and postgerminative growth. ABA treatment induces the degradation of MIEL1 and represses the interaction between MIEL1 and ABI5/MYB30, thus releasing both ABI5 and MYB30. Our results demonstrate that MIEL1 directly mediates the proteasomal degradation of ABI5 and inhibits its activity via the release of its target protein MYB30, thus ensuring precise ABA signaling during seed germination and seedling establishment.
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Proteínas de Arabidopsis , Arabidopsis , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Sementes/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
The unique morphology of grass stomata enables rapid responses to environmental changes. Deciphering the basis for these responses is critical for improving food security. We have developed a planta platform of single-nucleus RNA-sequencing by combined fluorescence-activated nuclei flow sorting, and used it to identify cell types in mature and developing stomata from 33,098 nuclei of the maize epidermis-enriched tissues. Guard cells (GCs) and subsidiary cells (SCs) displayed differential expression of genes, besides those encoding transporters, involved in the abscisic acid, CO2, Ca2+, starch metabolism, and blue light signaling pathways, implicating coordinated signal integration in speedy stomatal responses, and of genes affecting cell wall plasticity, implying a more sophisticated relationship between GCs and SCs in stomatal development and dumbbell-shaped guard cell formation. The trajectory of stomatal development identified in young tissues, and by comparison to the bulk RNA-seq data of the MUTE defective mutant in stomatal development, confirmed known features, and shed light on key participants in stomatal development. Our study provides a valuable, comprehensive, and fundamental foundation for further insights into grass stomatal function.
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Estômatos de Plantas , Zea mays , Humanos , Folhas de Planta/metabolismo , Estômatos de Plantas/metabolismo , Poaceae/genética , Transcriptoma/genética , Zea mays/genéticaRESUMO
Plants face a more volatile environment than other organisms because of their immobility, and they have developed highly efficient mechanisms to adapt to stress conditions. Transcription factors, as an important part of the adaptation process, are activated by different signals and are responsible for the expression of stress-responsive genes. MYB transcription factors, as one of the most widespread transcription factor families in plants, participate in plant development and responses to stresses by combining with MYB cis-elements in promoters of target genes. MYB transcription factors have been extensively studied and have proven to be critical in the biosynthesis of secondary metabolites in plants, including anthocyanins, flavonols, and lignin. Multiple studies have now shown that MYB proteins play diverse roles in the responses to abiotic stresses, such as drought, salt, and cold stresses. However, the regulatory mechanism of MYB proteins in abiotic stresses is still not well understood. In this review, we will focus mainly on the function of Arabidopsis MYB transcription factors in abiotic stresses, especially how MYB proteins participate in these stress responses. We also pay attention to how the MYB proteins are regulated in these processes at both the transcript and protein levels.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Secas , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico , Fatores de Transcrição/metabolismo , Proteínas de Arabidopsis/genética , Fatores de Transcrição/genéticaRESUMO
Metal-air batteries, like Zn-air batteries (ZABs) are usually suffered from low energy conversion efficiency and poor cyclability caused by the sluggish OER and ORR at the air cathode. Herein, a novel bimetallic Co/CoFe nanomaterial supported on nanoflower-like N-doped graphitic carbon (NC) was prepared through a strategy of coordination construction-cation exchange-pyrolysis and used as a highly efficient bifunctional oxygen electrocatalyst. Experimental characterizations and density functional theory calculations reveal the formation of Co/CoFe heterostructure and synergistic effect between metal layer and NC support, leading to improved electric conductivity, accelerated reaction kinetics, and optimized adsorption energy for intermediates of ORR and OER. The Co/CoFe@NC exhibits high bifunctional activities with a remarkably small potential gap of 0.70 V between the half-wave potential (E1/2) of ORR and the potential at 10 mA cmâ2 (Ej=10) of OER. The aqueous ZAB constructed using this air electrode exhibits a slight voltage loss of only 60 mV after 550-cycle test (360 h, 15 days). A sodium polyacrylate (PANa)-based hydrogel electrolyte was synthesized with strong water-retention capability and high ionic conductivity. The quasi-solid-state ZAB by integrating the Co/CoFe@NC air electrode and PANa hydrogel electrolyte demonstrates excellent mechanical stability and cyclability under different bending states.
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In this study, we have developed intriguing self-supporting caterpillar-like spinel NiCo2S4 arrays with a hierarchical structure of nanowires on a nanosheet skeleton, which can be used as a self-supporting trifunctional electrocatalyst for the oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and urea oxidation reaction (UOR). The caterpillar-like NiCo precursor arrays are first in situ grown on carbon cloth (NiCo2O4/CC) by a facile hydrothermal reaction, which is followed by an anion exchange process (or sulfuration treatment) with Na2S to form self-supporting spinel NiCo2S4 arrays (NiCo2S4/CC) with a roughened nanostructure. Taking advantage of the bimetallic synergistic effect, the unique hierarchical nanostructure, and the self-supporting nature, the resultant NiCo2S4/CC electrode exhibits high activities toward the OER, HER and UOR, which are highly superior to the monometallic counterparts of NiS nanosheets and Co9S8 nanowires on a carbon cloth substrate. The comparison of the three electrodes also indicates that the hierarchically structured bimetallic electrode combines the morphological and structural characteristics of monometallic Ni-based nanosheets and Co-based nanowires. When assembling a two-electrode electrolytic cell with NiCo2S4/CC as both the anode and cathode, an applied cell voltage of only 1.66 V is required to deliver a current density of 10 mA cm-2 in water electrolysis. By using the same two-electrode setup, the applied voltage for urea electrolysis is further reduced to 1.45 V that produces hydrogen at the cathode with the same current density. This study paves the way for exploring the feasibility of future less energy-intensive and large-scale hydrogen production.