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The investigation of suitable organic host materials is crucial for the development of high-efficiency triplet exciton-based organic light emitting diodes (OLEDs). In this study, two isomeric carbazole/1,3,5-triazine hybrid bipolar-transport host materials o-3CN-TRZ and o-4CN-TRZ are developed. The alteration of cyano substitution from the 3- to the 4-position of carbazole resulted in a slight reduction in the HOMO levels from −5.80 to −5.87 eV, accompanied by a gentle decline in the singlet/triplet energy levels. This was evidenced by a shift in the fluorescence emission peak from 450 to 474 nm and the observation of relatively high triplet energies of 2.79 and 2.77 eV for o-3CN-TRZ and o-4CN-TRZ, respectively. Notably, compared to the bare carbazole-based model compound o-Cz-TRZ, the introduction of a cyano group at either the 3- or the 4-position led to a notable enhancement in the electron-transport properties. However, the hole-transport behavior of o-3CN-TRZ was evidently inferior to that of o-4CN-TRZ. Therefore, when employed as host materials for both phosphorescence and thermally activated delayed fluorescence OLEDs, o-4CN-TRZ hosted devices all exhibited higher efficiencies than o-3CN-TRZ. Maximum external quantum efficiencies of 20.5, 16.8 and 16.9% versus 19.6, 12.5 and 13.8% were achieved for green phosphorescent (ppy)2Ir(acac), greenish-yellow TADF 4tCzDOXD and 4tCzCNPy-based devices, respectively. [ABSTRACT FROM AUTHOR]

Both DNA 5-methylcytosine (5mC) and RNA N6-methyladenosine (m6A) modifications are reported to participate in cellular stress responses including inflammation. Phosphoenolpyruvate carboxykinase 2 (PCK2) is upregulated in Kupffer cells (KCs) to facilitate the proinflammatory phosphorylation signaling cascades upon LPS stimulation, yet the role of 5mC and m6A in PCK2 upregulation remain elusive. Here, we report that the significantly augmented PCK2 mRNA and protein levels are associated with global 5mC demethylation coupled with m6A hypermethylation in LPS-activated KCs. The suppression of 5mC demethylation or m6A hypermethylation significantly alleviates the upregulation of PCK2 and proinflammatory cytokines in LPS-challenged KCs. Further reciprocal tests indicate 5mC demethylation is upstream of m6A hypermethylation. Specifically, CpG islands in the promoters of PCK2 and RNA methyltransferase (METTL3 and METTL14) genes are demethylated, while the 3′UTR of PCK2 mRNA is m6A hypermethylated, in LPS-stimulated KCs. These modifications contribute to the transactivation of the PCK2 gene as well as increased PCK2 mRNA stability and protein production via a m6A-mediated mechanism with IGF2BP1 as the reader protein. These results indicate that DNA 5mC and RNA m6A collaborate to upregulate PCK2 expression, respectively, at the transcriptional and post-transcriptional levels during KC activation. [ABSTRACT FROM AUTHOR]

Objective To explore the possible key pathways in the male reproductive toxicity induced by exposure to low-dose bisphenol A (BPA). Methods BPA-related genes were screened based on Comparative Toxicogenomics Database (CTD). Functional enrichment analysis was used for these genes to explore the possible pathways and identify the key genes in related pathways. Mouse spermatogonia cell line GC-2 cells were treated with BPA at a final concentration of 0 (DMSO control group), 20, 40 and 80 μmol/L for 72 h. Then the changes of cell morphology and apoptotic rate were observed. The mRNA and protein expression levels of the obtained key genes were detected by RT-qPCR and Western blotting, respectively. Results A total of 1 460 BPA-related genes were screened out from the CTD database. Gene Ontology (GO) enrichment analysis showed that these genes were significantly enriched in molecular biological processes, such as reproductive system development and reproductive structure development, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis found that they were significantly enriched in HIF-1 and PI3K-Akt signaling pathways (P < 0.01). Visual analysis showed that the key genes in the pathway were HIF-1α, PKC and P300/CBP, and PI3K, JAK, P53 and BCL-2. The apoptotic rate of GC-2 cells exposed to BPA was significantly increased in a dose-dependent manner (P < 0.05). Compared with the control cells, the mRNA expression levels of PI3K and JAK were significantly down-regulated, while those of P53 and BCL-2 were up-regulated (P < 0.05). The protein levels of PI3K and BCL-2 were obviously down-regulated, while that of P53 up-regulated (P < 0.05). Conclusion The PI3K-Akt signaling pathway may play an important role in the process of GC-2 cell apoptosis induced by low-dose BPA exposure.

It is easier and cheaper to prevent forest fires than to extinguish them, therefore, the development of long-lasting and environmentally friendly fire-retarding materials is highly desirable to prevent the spread of forest fires. In this study, soluble carboxymethyl starch replaced insoluble carboxymethyl cellulose to improve the compressive strength of inorganic gel and overcome the weakness of fragility. When the concentration of polymer carboxymethyl starch and crosslinking agent aluminum citrate were 0.5% and 0.3%, respectively, the inorganic/organic composite gel showed the best comprehensive performance (including gelation time, water retention, seepage velocity and strength). Additionally, the antioxidant tannin was introduced into the inorganic/organic gel, which effectively inhibited the oxidation of wood flour, making its inhibition rate reached 23.1%, about twice that of pure inorganic gel. This is mainly attributed to the ability of tannin to inhibit the oxidation process of active groups, including carbon-oxygen, hydroxyl, and methyl of the wood powder, thereby enhancing the flame resistance of the composite gel. Probable mechanism of forest fire suppression by the antioxidant composite gel is proposed, which involves oxygen isolation, evaporative cooling, and chain reaction inhibition. [ABSTRACT FROM AUTHOR]

This study addresses the challenges of time‐delay and low accuracy in online gas‐phase composition monitoring during olefin copolymerization processes. Three flowmeters based on different mechanisms are installed in series to measure the real‐time exhaust gas flow rate from the reactor. For the same gas flow, the three flowmeters display different readings, which vary with the properties and composition of the gas mixture. Consequently, the composition of the mixed gas can be determined by analyzing the reading of the three flowmeters. Fitting equations and three machine learning models, namely decision trees, random forests, and extreme gradient boosting, are employed to calculate the gas composition. The results from cold‐model experimental data demonstrate that the XGBoost model outperforms others in terms of accuracy and generalization capabilities. For the concentration of ethylene, propylene, and hydrogen, the determination coefficients (R2) were 0.9852, 0.9882, and 0.9518, respectively, with corresponding normalized root mean square error (NRMSE) values of 0.0352, 0.0312, and 0.0706. The effectiveness of the online monitoring device is further validated through gas phase copolymerization experiments involving ethylene and propylene. The yield and composition of the ethylene and propylene copolymers are successfully predicted using the online measurement data. [ABSTRACT FROM AUTHOR]