Highly efficient and bright blue organic light-emitting devices based on solvent engineered, solution-processed thermally activated delayed fluorescent emission layer

In this work, we use an efficient blue TADF emitter, bis [4-(9,9-dimethyl-9,10-dihydroacridine) phenyl]solfone (DMAC-DPS), as EML and propose a solvent engineering strategy to achieve high efficiency and brightness. The strategy employs synergetic solvents to improve the film morphology of the solution-processed DMAC-DPS EML. The improved film quality enhances the carrier injectionwhile reduces the surface trap charges, as revealed by the hole-/ electron-only device performance and the transient electroluminescence measurements

High efficient all-solution OLEDs and their transient electroluminescence

Solution-processed OLEDs have always been the hot topic in the research of OLEDs. The electron-hole evolution in all solution processed OLEDs involves the carrier transportation, the exciton recombination and dissociation.The dynamic of excitons plays a crucial role in governing the ultimate device performance

B1 SINE-binding ZFP266 impedes mouse iPSC generation through suppression of chromatin opening mediated by reprogramming factors

Induced pluripotent stem cell (iPSC) reprogramming is inefficient and understanding the molecular mechanisms underlying this inefficiency holds the key to successfully control cellular identity. Here, we report 24 reprogramming roadblock genes identified by CRISPR/Cas9-mediated genome-wide knockout (KO) screening. Of these, depletion of the predicted KRAB zinc finger protein (KRAB-ZFP) Zfp266 strongly and consistently enhances murine iPSC generation in several reprogramming settings, emerging as the most robust roadblock. We show that ZFP266 binds Short Interspersed Nuclear Elements (SINEs) adjacent to binding sites of pioneering factors, OCT4 (POU5F1), SOX2, and KLF4, and impedes chromatin opening. Replacing the KRAB co-suppressor with co-activator domains converts ZFP266 from an inhibitor to a potent facilitator of iPSC reprogramming. We propose that the SINE-KRAB-ZFP interaction is a critical regulator of chromatin accessibility at regulatory elements required for efficient cellular identity changes. In addition, this work serves as a resource to further illuminate molecular mechanisms hindering reprogramming.Induced pluripotent stem cell (iPSC) reprogramming is inherently inefficient. Here the authors identify 24 reprogramming roadblock genes through a CRISPR/Cas9-mediated genome-wide knockout screen including a KRAB-ZFP Zfp266, knockout of which consistently enhances murine iPSC generation.Peer reviewe

Regulation of energy band and luminescence properties in blue quasi-2D lead bromide perovskite via lattice strain

Development of blue quasi-2D lead halide perovskite LEDs is key to the perovskite based full-color displays and white-light illumination. It is still quite challenging to accurately enlarge the bandgap to achieve high performance and stable blue Quasi-2D perovskite LEDs. The lattice strain due to the deformation of lead-bromide octahedra is a critical factor leading to the energy band adjustment and stability optimization. In this Letter, the lattice strain is adjusted via three cations with different sizes, Cs+, CH3CH2NH2+(EA+), and Rb+, for sophisticatedly micro-tuning of the lattice strain to achieve overall lattice expansion and lattice contraction. A ternary quasi-2D blue bromide perovskite material PEA 2 (Cs xEAyRb1-x-yPbBr)2 PbBr 4 is specially designed. The crystal structure and energy band are studied by the first principles calculations using the Density Functional Theory method. The luminescence properties of blue quasi-2D lead bromide perovskite materials are analyzed with spectra regulation from 508 to 464 nm for photoluminescence and from 510 to 470 nm for electroluminescence. The thermal treatment is used to accelerate the release of residual strain due to mismatch and disorder in the lattice, leading to defects and degradation. The lattice strain is strongly correlated with the energy band, luminescence performance, and thermal stability of blue quasi-2D lead bromide perovskite. The study of lattice strain relaxation in blue quasi-2D lead bromide perovskite could open avenues for high-performance and stable blue quasi-2D perovskite LEDs

Analysis of <i>Runx1</i> Using Induced Gene Ablation Reveals Its Essential Role in Pre-liver HSC Development and Limitations of an <i>In Vivo</i> Approach

Summary: Hematopoietic stem cells (HSCs) develop in the embryonic aorta-gonad-mesonephros (AGM) region and subsequently relocate to fetal liver. Runx1 transcription factor is essential for HSC development, but is largely dispensable for adult HSCs. Here, we studied tamoxifen-inducible Runx1 inactivation in vivo. Induction at pre-liver stages (up to embryonic day 10.5) reduced erythromyeloid progenitor numbers, but surprisingly did not block the appearance of Runx1-null HSCs in liver. By contrast, ex vivo analysis showed an absolute Runx1 dependency of HSC development in the AGM region. We found that, contrary to current beliefs, significant Cre-inducing tamoxifen activity persists in mouse blood for at least 72 hr after injection. This deferred recombination can hit healthy HSCs, which escaped early Runx1 ablation and result in appearance of Runx1-null HSCs in liver. Such extended recombination activity in vivo is a potential source of misinterpretation, particularly in analysis of dynamic developmental processes during embryogenesis. : The authors found that Cre-mediated Runx1 ablation induced in vivo at pre-liver stages resulted in appearance of Runx1-null HSCs in the fetal liver. By contrast, deletion of Runx1 in cultured AGM region fully blocked HSC development. Appearance of Runx1-null HSCs in the liver is explained by presence of uncontrolled long-lasting (at least 3 days) Cre-inducing tamoxifen activity in vivo. Keywords: Runx1, hematopoietic stem cells, AGM, development, hematopoiesis, conditional knockout, tamoxife

Ubiquitous conservative interaction patterns between post-spliced introns and their mRNAs revealed by genome-wide interspecies comparison

Introns, as important vectors of biological functions, can influence many stages of mRNA metabolism. However, in recent research, post-spliced introns are rarely considered. In this study, the optimal matched regions between introns and their mRNAs in nine model organism genomes were investigated with improved Smith–Waterman local alignment software. Our results showed that the distributions of mRNA optimal matched frequencies were highly consistent or universal. There are optimal matched frequency peaks in the UTR regions, which are obvious, especially in the 3′-UTR. The matched frequencies are relatively low in the CDS regions of the mRNA. The distributions of the optimal matched frequencies around the functional sites are also remarkably changed. The centers of the GC content distributions for different sequences are different. The matched rate distributions are highly consistent and are located mainly between 60% and 80%. The most probable value of the optimal matched segments is about 20 bp for lower eukaryotes and 30 bp for higher eukaryotes. These results show that there are abundant functional units in the introns, and these functional units are correlated structurally with all kinds of sequences of mRNA. The interaction between the post-spliced introns and their corresponding mRNAs may play a key role in gene expression

Modification of PEDOT: PSS to enhance device efficiency and stability of the Quasi-2D perovskite light-emitting diodes

Poly(3,4-ethylenedioxy thiophene): poly(styrene sulfonate) (PEDOT: PSS) is a hole transport layer (HTL) that is often employed in a diverse array of optoelectronic devices, such as perovskite solar cells and perovskite light-emitting diodes (PeLEDs). By simply doping lithium fluoride (LiF) into PEDOT: PSS, we demonstrate that the electrical characteristics of the HTL can be modified. Especially in quasi-2D perovskite LEDs, the crystallization process is regulated by LiF modification, leading to reduced phase impurity defects and improved carrier transport in the perovskite emission layer. Therefore, the luminance and efficiency of the quasi-2D PeLEDs are notably enhanced. The optimized PeLED with LiF modification exhibits a peak luminance of 21517 cd m−2 with 317% higher than the standard PeLED; and a high current efficiency of 39.8 cd A−1 with 237% higher than the standard PeLED. Moreover, the device stability is also improved with a nearly doubled half lifetime due to the reduced phase impurities. The work demonstrates a facile yet effective method for altering PEDOT: PSS hole transport layer, emphasizing the critical role of the underneath layer in the crystallization of quasi-2D perovskites

bSRWPSO-FKNN: A boosted PSO with fuzzy K-nearest neighbor classifier for predicting atopic dermatitis disease

IntroductionAtopic dermatitis (AD) is an allergic disease with extreme itching that bothers patients. However, diagnosing AD depends on clinicians’ subjective judgment, which may be missed or misdiagnosed sometimes.MethodsThis paper establishes a medical prediction model for the first time on the basis of the enhanced particle swarm optimization (SRWPSO) algorithm and the fuzzy K-nearest neighbor (FKNN), called bSRWPSO-FKNN, which is practiced on a dataset related to patients with AD. In SRWPSO, the Sobol sequence is introduced into particle swarm optimization (PSO) to make the particle distribution of the initial population more uniform, thus improving the population’s diversity and traversal. At the same time, this study also adds a random replacement strategy and adaptive weight strategy to the population updating process of PSO to overcome the shortcomings of poor convergence accuracy and easily fall into the local optimum of PSO. In bSRWPSO-FKNN, the core of which is to optimize the classification performance of FKNN through binary SRWPSO.ResultsTo prove that the study has scientific significance, this paper first successfully demonstrates the core advantages of SRWPSO in well-known algorithms through benchmark function validation experiments. Secondly, this article demonstrates that the bSRWPSO-FKNN has practical medical significance and effectiveness through nine public and medical datasets.DiscussionThe 10 times 10-fold cross-validation experiments demonstrate that bSRWPSO-FKNN can pick up the key features of AD, including the content of lymphocytes (LY), Cat dander, Milk, Dermatophagoides Pteronyssinus/Farinae, Ragweed, Cod, and Total IgE. Therefore, the established bSRWPSO-FKNN method practically aids in the diagnosis of AD

Hierarchical organization and early hematopoietic specification of the developing HSC lineage in the AGM region

A CD45-negative population of pre-HSCs develops into definitive HSCs in the AGM region of the embryo