Metal halide perovskites are attracting a lot of attention as next-generation light-emitting materials owing to their excellent emission properties, with narrow band emission
. However, perovskite ...light-emitting diodes (PeLEDs), irrespective of their material type (polycrystals or nanocrystals), have not realized high luminance, high efficiency and long lifetime simultaneously, as they are influenced by intrinsic limitations related to the trade-off of properties between charge transport and confinement in each type of perovskite material
. Here, we report an ultra-bright, efficient and stable PeLED made of core/shell perovskite nanocrystals with a size of approximately 10 nm, obtained using a simple in situ reaction of benzylphosphonic acid (BPA) additive with three-dimensional (3D) polycrystalline perovskite films, without separate synthesis processes. During the reaction, large 3D crystals are split into nanocrystals and the BPA surrounds the nanocrystals, achieving strong carrier confinement. The BPA shell passivates the undercoordinated lead atoms by forming covalent bonds, and thereby greatly reduces the trap density while maintaining good charge-transport properties for the 3D perovskites. We demonstrate simultaneously efficient, bright and stable PeLEDs that have a maximum brightness of approximately 470,000 cd m
, maximum external quantum efficiency of 28.9% (average = 25.2 ± 1.6% over 40 devices), maximum current efficiency of 151 cd A
and half-lifetime of 520 h at 1,000 cd m
(estimated half-lifetime >30,000 h at 100 cd m
). Our work sheds light on the possibility that PeLEDs can be commercialized in the future display industry.
The small nanoparticle size and long-chain ligands in colloidal metal halide perovskite quantum dots (PeQDs) cause charge confinement, which impedes exciton dissociation and carrier extraction in ...PeQD solar cells, so they have low short-circuit current density J
, which impedes further increases in their power conversion efficiency (PCE). Here, a re-assembling process (RP) is developed for perovskite nanocrystalline (PeNC) films made of colloidal perovskite nanocrystals to increase J
in PeNC solar cells. The RP of PeNC films increases their crystallite size and eliminates long-chain ligands, and thereby overcomes the charge confinement in PeNC films. These changes facilitate exciton dissociation and increase carrier extraction in PeNC solar cells. By use of this method, the gradient-bandgap PeNC solar cells achieve a J
= 19.30 mA cm
without compromising the photovoltage, and yield a high PCE of 16.46% with negligible hysteresis and good stability. This work provides a new strategy to process PeNC films and pave the way for high performance PeNC optoelectronic devices.
Monolayer transition metal dichalcogenides (TMDs) have drawn significant attention for their potential in optoelectronic applications due to their direct band gap and exceptional quantum yield. ...However, TMD‐based light‐emitting devices have shown low external quantum efficiencies as imbalanced free carrier injection often leads to the formation of non‐radiative charged excitons, limiting practical applications. Here, electrically confined electroluminescence (EL) of neutral excitons in tungsten diselenide (WSe2) light‐emitting transistors (LETs) based on the van der Waals heterostructure is demonstrated. The WSe2 channel is locally doped to simultaneously inject electrons and holes to the 1D region by a local graphene gate. At balanced concentrations of injected electrons and holes, the WSe2 LETs exhibit strong EL with a high external quantum efficiency (EQE) of ≈8.2 % at room temperature. These experimental and theoretical results consistently show that the enhanced EQE could be attributed to dominant exciton emission confined at the 1D region while expelling charged excitons from the active area by precise control of external electric fields. This work shows a promising approach to enhancing the EQE of 2D light‐emitting transistors and modulating the recombination of exciton complexes for excitonic devices.
This work demonstrates electrically confined electroluminescence of neutral excitons in WSe2 light‐emitting transistors (LETs). By balancing injected electrons and holes, and electrically confining neutral excitons, WSe2 LETs exhibit strong electroluminescence with a high external quantum efficiency of ≈8.2 % at room temperature. This work shows a promising approach to enhancing efficiency and modulating the recombination of exciton complexes for 2D excitonic devices.
Microbial biodegradation is a primary pesticide remediation pathway. Despite diazinon is one of the most frequently used organophosphate insecticides worldwide, its effect on soil microbial community ...remains obscure. We hypothesize that diazinon exposure reshapes microbial community, among them increased microbes may play a crucial role in diazinon degradation. To investigate this, we collected soil from an organic farming environment, introduced diazinon, cultivated it in a greenhouse, and then assessed its effects on soil microbiomes at three distinct time points: 20, 40, and 270 days after treatment (DAT). Results from HPLC showed that the level of diazinon was gradually degraded by 98.8% at 270 DAT when compared with day zero, whereas 16S rRNA gene analysis exhibited a significant reduction in the bacterial diversity, especially at the early two time points, indicating that diazinon may exert selection pressure to the bacteria community. Here, the relative abundance of phylum Actinomycetota increased at 20 and 40 DATs. In addition, the bacterial functional gene profile employing PICRUSt2 prediction also revealed that diazinon exposure induced the genomic function related to xenobiotics biodegradation and metabolism in soil, such as CYB5B, hpaC, acrR, and ppkA. To validate if bacterial function is caused by increased relative abundance in diazinon enriched soil, further bacteria isolation resulted in obtaining 25 diazinon degradation strains out of 103 isolates. Notably, more than 70% (18 out of 25) isolates are identified as phylum Actinomycetota, which empirically confirms and correlates microbiome and PICRUSt2 results. In conclusion, this study provides comprehensive information from microbiome analysis to obtaining several bacteria isolates responsible for diazinon degradation, revealing that the phylum Actinomycetota is as a key taxon that facilitates microbial biodegradation in diazinon spoiled soil. This finding may assist in developing a strategy for microbial detoxification of diazinon, such as using an Actinomycetota rich synthetic community (SynCom).
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•Microbial composition in diazinon-exposed microcosm soil were analyzed.•Selection pressure by diazinon orchestrated the flourishing of the phylum Actinomycetota.•Network analysis revealed that the phylum Actinomycetota pose a central role within the microbial community.•Among diazinon-biodegradable-bacteria isolates, the largest proportion (70%) were affiliated with the phylum Actinomycetota.•Microbiome study at the site of pesticides exposure is a promising strategy in finding elite pesticide-biodegrading microbes.
Emerging evidence suggests that oxidative/nitrosative stress, as occurs during aging, contributes to the pathogenesis of Parkinson's disease (PD). In contrast, detoxification of reactive oxygen ...species and reactive nitrogen species can protect neurons. DJ-1 has been identified as one of several recessively inherited genes whose mutation can cause familial PD, and inactivation of DJ-1 renders neurons more susceptible to oxidative stress and cell death. DJ-1 is also known to regulate the activity of the phosphatase and tensin homolog (PTEN), which plays a critical role in neuronal cell death in response to various insults. However, mechanistic details delineating how DJ-1 regulates PTEN activity remain unknown. Here, we report that PTEN phosphatase activity is inhibited via a transnitrosylation reaction i.e., transfer of a nitric oxide (NO) group from the cysteine residue of one protein to another. Specifically, we show that DJ-1 is S-nitrosylated (forming SNO-DJ-1); subsequently, the NO group is transferred from DJ-1 to PTEN by transnitrosylation. Moreover, we detect SNO-PTEN in human brains with sporadic PD. Using x-ray crystallography and site-directed mutagenesis, we find that Cys106 is the site of S-nitrosylation on DJ-1 and that mutation of this site inhibits transnitrosylation to PTEN. Importantly, S-nitrosylation of PTEN decreases its phosphatase activity, thus promoting cell survival. These findings provide mechanistic insight into the neuroprotective role of SNO-DJ-1 by elucidating how DJ-1 detoxifies NO via transnitrosylation to PTEN. Dysfunctional DJ-1, which lacks this transnitrosylation activity due to mutation or prior oxidation (e.g., sulfonation) of the critical cysteine thiol, could thus contribute to neurodegenerative disorders like PD.
Abstract
The gearbox has the advantage of being able to change the torque and rotational speed according to the gear ratio and has high power transmission efficiency by transmitting power through the ...contact of the gear pair. When evaluating the strength and fatigue life of a gearbox using a design load or an equivalent load, there is a possibility that the results will be very different from the actual ones. Therefore, in this study, the load duration distribution (LDD) constructed based on the actual workload was used to evaluate the strength and fatigue life of the gearbox reliably. As a result of evaluating the strength and fatigue life of the gearbox using LDD, it was confirmed that the existing gearbox did not satisfy the target lifespan in the operating environment. Therefore, the reasons for these results were analyzed, and design modification was performed based on the analyzed results. As a result of design modification, shaft deflection decreased by rearrangement of the bearings, from an overhung type to a straddle type, thereby improving the fatigue life of gears and bearings. Finally, the load distribution acting on the gear tooth surface was improved through micro-geometry modification of the gears.
Electrically Confined Electroluminescence
In article number 2310498, Gwan‐Hyoung Lee and co‐workers demonstrate electrically confined electroluminescence of neutral excitons in WSe2 light‐emitting ...transistors (LETs). By achieving balanced concentrations of injected electrons and holes, and confining neutral exciton within the 1D region, the WSe2 LETs exhibit strong electroluminescence with a high external quantum efficiency (EQE) of ≈8.2% at room temperature, which will be a promising approach to enhancing the EQE and modulating exciton complexes for 2D excitonic devices.
Tractor cab interior noise is a risk factor that degrades operators' work performance and threatens their health; therefore, the noise must be reduced to ensure farmworkers' safety and efficiency. ...Cab interior noise can be classified as structure-borne noise and air-borne noise. Structure-borne noise has been extensively studied. However, although air-borne noise greatly contributes to cab interior noise, detailed frequency-domain analyses have not been performed. In this study, the components of cab interior noise were identified in the frequency domain through an order analysis, which helped improve the sound insulation of the cab and reduce the effects of air-borne noise. A test was performed while driving a tractor on a chassis dynamometer in a semi-anechoic chamber for reproducible measurement and evaluation. The A-weighted sound pressure was transformed by a fast Fourier transform algorithm, and its order was tracked by the engine speed signal. In addition, a direct path was identified by acoustic images using a sound camera. The contributions of major noise sources were identified through an order analysis. We proved that air-borne noise significantly contributes to the interior noise of tractor cabs and that improvement of the cab sound insulation is an effective noise-reduction technique.
Our aim was to verify the potential ability of succinylacetone (SA) to inhibit mitochondrial function, thereby suppressing cancer cell proliferation. SA treatment caused apoptosis in HCT116 and HT29 ...cells, but not in SW480 cells, with mitochondria playing a key role. We checked for dysfunctional mitochondria after SA treatment. Mitochondria of HT29 cells were swollen, indicating damage, whereas in HCT116 cells, several mitochondria had a diminished size. Damaged mitochondria decreased ATP production and induced reactive oxygen species (ROS) in the cells. To understand SA-induced reduction in ATP production, we investigated the electron transfer chains (ETC) and pyruvate dehydrogenase kinase (PDK) activity, which prevents the transfer of acetyl-CoA to the TCA (tricarboxylic acid) cycle by inhibiting PDH (pyruvate dehydrogenase) activity. In each cell line, the inhibitory mechanism of ATP by SA was different. The activity of complex III consisting of the mitochondrial ETCs in HT29 cells was decreased. In contrast, PDH activity in HCT116 cells was reduced. Nicotinamide nucleotide transhydrogenase (NNT)-removing reactive oxygen species (ROS) was upregulated in HT29 cells, but not in HCT116 cells, indicating that in HT29 cells, a defense mechanism was activated against ROS. Collectively, our study showed a differential mechanism occurs in response to SA in colon cancer cells.
•Defatted sesame meal is a good source to isolate and purify sesamin and sesamolin.•Consecutive sample injection into CPC was developed to purify sesamin and sesamolin from defatted sesame meal ...extract.•Scale-up of CPC with 1000mL rotor was carried out according to 100mL rotor results.•The antioxidant response element (ARE) activating effects of sesamin and sesamolin were evaluated by luciferase assays in HepG2 cells.
A preparative separation method using consecutive sample injection centrifugal partition chromatography (CPC) was developed to obtain sesamin and sesamolin from defatted sesame meal extracts. A two-phase solvent system consisting of n-hexane–ethyl acetate–methanol–water (8:2:8:2, v/v) was applied in reversed-phase mode (descending mode). Preliminary experiments with an SCPC-100 (column volume: 100mL) were performed to select the appropriate two-phase solvent system and sample injection times; these parameters were then used with an SCPC-1000 (column volume: 1000mL) in a 10-fold scale-up preparative run. A sample containing 3g of crude extract was consecutively injected four times onto the SCPC-1000, which yielded 328mg of sesamin and 168mg of sesamolin. These compounds were analyzed by high-performance liquid chromatography and determined to have purities of 95.6% and 93.9%, respectively. Sesamin and sesamolin (30μM) increased antioxidant response element (ARE) luciferase activity 2.6-fold and 1.9-fold, respectively.
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