Simultaneously achieving both a high efficiency and long lifetime in deep-blue organic light-emitting diodes is challenging. Here we report thermally activated delayed fluorescence (TADF) organic ...light-emitting diodes that aim to meet this goal by combining a new design of blue TADF materials with a triplet-exciton recycling protocol. Two TADF materials, one distributing and one emitting, were doped into a host to form triplet-exciton-distributed TADF devices. The singlet excitons were transferred from the host to the emitter via the distributing TADF material by cascade energy transfer, whereas the triplet excitons were transferred to the emitter as singlet excitons by a triplet-exciton recycling process between the low-triplet-energy host and the distributing TADF material. The resulting triplet-exciton-distributed TADF devices achieved a high external quantum efficiency of 33.5 ± 0.1, a colour coordinate corrected current efficiency over 400 cd A–1, a lifetime of >5,000 h and a y colour coordinate below 0.10.Exciton energy cascade transfer and recycling bring improvements in the efficiency and lifetime of deep-blue organic light-emitting diodes.
Illumina sequencing is a representative tool for understanding the massive diversity of microbial eukaryotes in natural ecosystems. Here, we investigated the eukaryotic community in a pond (salinity ...of 2-4) on Dokdo (island) in the East Sea, Korea, using Illumina sequencing with primer sets for the V4 and V9 regions of 18S rDNA from 2016 to 2018 for the first time. Totally, 1,413 operational taxonomic units (OTUs) and 915 OTUs were detected using the V9 and V4 primer sets, respectively. Taxonomic analyses of these OTUs revealed that although the V4 primer set failed to describe the extant diversity for some major sub-division groups, the V9 primer set represented their diversity. Moreover, the rare taxa with <1% of total reads were exclusively detected using V9 primer set. Hence, the diversity of the eukaryotic community can vary depending on the choice of primers. The Illumina sequencing data of the V9 region of 18S rDNA may be advantageous for estimating the richness of the eukaryotic community including a rare biosphere, whereas the simultaneous application of two biomarkers may be suitable for understanding the molecular phylogenetic relationships. We strongly recommend both biomarkers be used to assess the diversity and phylogenetic relationship within the eukaryotic community in natural samples.
The plasma jet has been proposed as a novel therapeutic method for cancer. Anticancer activity of plasma has been reported to involve mitochondrial dysfunction. However, what constituents generated ...by plasma is linked to this anticancer process and its mechanism of action remain unclear. Here, we report that the therapeutic effects of air plasma result from generation of reactive oxygen/nitrogen species (ROS/RNS) including H2O2, Ox, OH-, •O2, NOx, leading to depolarization of mitochondrial membrane potential and mitochondrial ROS accumulation. Simultaneously, ROS/RNS activate c-Jun NH2-terminal kinase (JNK) and p38 kinase. As a consequence, treatment with air plasma jets induces apoptotic death in human cervical cancer HeLa cells. Pretreatment of the cells with antioxidants, JNK and p38 inhibitors, or JNK and p38 siRNA abrogates the depolarization of mitochondrial membrane potential and impairs the air plasma-induced apoptotic cell death, suggesting that the ROS/RNS generated by plasma trigger signaling pathways involving JNK and p38 and promote mitochondrial perturbation, leading to apoptosis. Therefore, administration of air plasma may be a feasible strategy to eliminate cancer cells.
Although the amount of petroleum residues produced from oil refinery processes has increased, there has been limited research for the residues. In this work, we developed petroleum residue-activated ...carbon (PAC) by chemical modification with citric acid as a novel adsorbent The optimal concentration of citric acid for PAC was chosen as the 6 M (named PAC-CA6) and the adsorption behavior of Co(II) was investigated. The experimental data were analyzed using various isotherm and kinetic models. The maximum adsorption capacity of 12.50 mg/g was determined using the Langmuir model. The pseudo-second-order model was found to be the most suitable for describing the adsorption kinetics. PAC-CA6 was characterized by using various instrumental analyses including FE-SEM, FTIR, and XPS. The Boehm titration method indicated the presence of multiple oxygen groups in PAC-CA6. Conclusively, the mechanism of Co(II) adsorption onto PAC-CA6 involved electrostatic interactions between Co(II) ions and carboxylic groups present on the surface of PAC-CA6. From the result, the PAC-CA6 could be sufficiently used as a potential adsorbent for the removal of cobalt from aqueous solutions.
Heavy metals contamination of water is one of the environmental issue globally. Thus prepared fly ash–based zeolite (FZA)–supported nano zerovalent iron and nickel (nZVI/Ni@FZA) bimetallic composite ...from low-cost fly ash waste for the potential treatment of anion (Cr(VI) and cation Cu(II)) heavy metals from industrial effluents at pH 3 and 5, respectively in this study. The systematic interaction between FZA and nZVI/Ni and the adsorptive removal mechanism was studied. The mean surface area of the nZVI/Ni@FZA (154.11 m2/g) was much greater than that of the FZA (46.6 m2/g) and nZVI (4.76 m2/g) independently, as determined by BET-N2 measurements. The effect of influence factors on the removal of Cr(VI) and Cu(II) by nZVI/Ni@FZA, such as pH effect, initial concentration effect, time effect, temperature effect, coexisting metals, and ionic strength, and cumulative loading ability, were discussed. The maximum adsorption capacity of nZVI/Ni@FZA was 48.31 mg/g and 147.06 mg/g towards Cr(VI) and Cu(II), respectively. These were higher than those of nZVI@FZA and FZA. It demonstrated that Ni could play an important role in enhancing the reduction ability of nZVI. Furthermore, isothermal and kinetic results revealed that both heavy metal adsorption processes were rate limiting monolayer Langmuir adsorption on homogeneous surfaces. Thermodynamic results suggested that the adsorptive removal of metal ions was endothermic with spontaneity. The applicability of nZVI/Ni@FZA on real industrial wastewater treatment results demonstrate that the concentration of heavy metals were removed under the acceptable standard levels. Further the adsorption capacity of nZVI/Ni@FZA was higher than the nZVI@FZA and FZA. The overall results demonstrated that nZVI/Ni@FZA was a promising, efficient, and economically feasible sorbent for potential wastewater treatment. Moreover this is first report on the preparation nZVI/Ni@FZA bimetallic composite.
•First report on the preparation and use of low-cost fly ash based zeolite-A-nZVI/Ni.•The prepared material well characterized using advanced techniques.•nZVI/Ni@FZA showed high removal efficiency for Cu(II) and Cr(VI) than zeolite.•The surface mechanism was well explained.•It was well applied for real industrial wastewater treatment.
High-entropy alloy (HEA) superconductors-a new class of functional materials-can be utilized stably under extreme conditions, such as in space environments, owing to their high mechanical hardness ...and excellent irradiation tolerance. However, the feasibility of practical applications of HEA superconductors has not yet been demonstrated because the critical current density (J
) for HEA superconductors has not yet been adequately characterized. Here, we report the fabrication of high-quality superconducting (SC) thin films of Ta-Nb-Hf-Zr-Ti HEAs via a pulsed laser deposition. The thin films exhibit a large J
of >1 MA cm
at 4.2 K and are therefore favorable for SC devices as well as large-scale applications. In addition, they show extremely robust superconductivity to irradiation-induced disorder controlled by the dose of Kr-ion irradiation. The superconductivity of the HEA films is more than 1000 times more resistant to displacement damage than that of other promising superconductors with technological applications, such as MgB
, Nb
Sn, Fe-based superconductors, and high-T
cuprate superconductors. These results demonstrate that HEA superconductors have considerable potential for use under extreme conditions, such as in aerospace applications, nuclear fusion reactors, and high-field SC magnets.
Background Recent evidence suggests that prenatal maternal distress increases the risk of allergic diseases in offspring. However, the effect of prenatal maternal depression and anxiety on atopic ...dermatitis (AD) risk remains poorly understood. Objective We investigated whether prenatal maternal distress is associated with AD risk in offspring and whether the mechanism is mediated by reactive oxygen species. Methods Two general population-based birth cohorts formed the study. One cohort (Cohort for Childhood Origin of Asthma and Allergic Diseases COCOA) consisted of 973 mother-baby dyads, and the other (Panel Study on Korean Children PSKC) consisted of 1531 mother-baby dyads. The association between prenatal distress and AD was assessed by using Cox proportional hazards and logistic regression models. In COCOA placental 11β-hydroxysteroid dehydrogenase type 2 and glutathione levels and serum IgE levels in 1-year-old children were measured. Results In COCOA and PSKC AD occurred in 30.6% (lifetime prevalence) and 11.6% (1 year prevalence) of offspring, respectively. Prenatal maternal distress increased the risk of AD in offspring, both in COCOA (hazard ratio for depression, 1.31 95% CI, 1.02-1.69; hazard ratio for anxiety, 1.41 95% CI, 1.06-1.89) and PSKC (odds ratio for distress, 1.85 95% CI, 1.06-3.25). In COCOA both prenatal maternal depression and anxiety scores were positively related to the predicted probability of AD ( P < .001 in both). Prenatal distress decreased placental glutathione to glutathione disulfide ratios ( P = .037) and, especially in those who later had AD, decreased placental 11β-hydroxysteroid dehydrogenase type 2 levels ( P = .010) and increased IgE levels at 1 year of age ( P = .005). Conclusion Prenatal maternal depression and anxiety promote risk of AD in offspring. Maternal distress increases the predicted probability of AD. The mechanism might involve chronic stress, abnormal steroid levels, and reactive oxygen species.
In this study, the antifungal effects of silver nano-particles (nano-Ag) and their mode of action were investigated. Nano-Ag showed antifungal effects on fungi tested with low hemolytic effects ...against human erythrocytes. To elucidate the antifungal mode of action of nano-Ag, flow cytometry analysis, a glucose-release test, transmission electron microscopy (TEM) and the change in membrane dynamics using 1,6-diphenyl-1,3,5-hexatriene (DPH), as a plasma membrane probe, were performed with Candida albicans. The results suggest nano-Ag may exert an antifungal activity by disrupting the structure of the cell membrane and inhibiting the normal budding process due to the destruction of the membrane integrity. The present study indicates nano-Ag has considerable antifungal activity, deserving further investigation for clinical applications.
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