The design and synthesis of organic materials with a narrow emission band in the longer wavelength region beyond 510 nm remain a great challenge. For constructing narrowband green emitters, we propose a unique molecular design strategy based on frontier molecular orbital engineering (FMOE), which can integrate the advantages of a twisted donor–acceptor (D‐A) structure and a multiple resonance (MR) delayed fluorescence skeleton. Attaching an auxiliary donor to a MR skeleton leads to a novel molecule with twisted D‐A and MR structure characteristics. Importantly, a remarkable red‐shift of the emission maximum and a narrowband spectrum are achieved simultaneously. The target molecule has been employed as an emitter to fabricate green organic light‐emitting diodes (OLEDs) with Commission Internationale de L'Eclairage (CIE) coordinates of (0.23, 0.69) and a maximum external quantum efficiency (EQE) of 27.0 %.

Abstract. The stability of Boolean networks and the stabilization of Boolean control networks are investigated. Using semi-tensor product of matrices and the matrix expression of logic, the dynamics of a Boolean (control) network can be converted to a discrete time linear (bilinear) dynamics, called the algebraic form of the Boolean (control) network. Then the stability can be revealed by analyzing the transition matrix of the corresponding discrete time system. Main results consist of two parts: (i) Using logic coordinate transformation, the known sufficient condition based on incidence matrix has been improved. It can also be used in stabilizer design. (ii) Based on algebraic form, necessary and sufficient conditions for stability and stabilization respectively are obtained.

Multiple‐resonance (MR) organic emitters bearing small full‐width at half‐maximum (FWHMs) are of general interest in organic light‐emitting diodes. Indolo[3,2,1‐jk]carbazole (ICz) embedded MR‐fluorophors have demonstrated extremely small FWHMs, yet in the violet region with low electroluminescence efficiency. Herein, a strategic implementation of ICz subunits into MR fluorophors is proposed by taking advantage of the synergetic effect of para‐positioned nitrogen atoms to enhance electronic coupling to decrease emitting energy gap. Deep blue emitters peaking at 441 and 447 nm with FWHMs of only 18 and 21 nm are thereof obtained, respectively, accompanied by ≈90 % photo‐luminance quantum yields. With the assistance of a thermally activated delayed fluorescence sensitizer to recycle excitons, the corresponding narrowband electroluminescent devices show unprecedent high maximum external quantum efficiencies of 32.0 % and 34.7 % with CIEy of 0.10 and 0.085, respectively.

BackgroundBreeding of rice cultivars with long-lasting resistance to the rice blast fungus Magnaporthe oryzae is difficult, and identification of new resistance genes is essential. Most of the loci associated with blast resistance against M. oryzae in rice have been identified in controlled environments and with single isolates, and such loci may confer resistance to only a small faction of the M. oryzae strains. In the field, however, rice is commonly attacked by multiple strains. Research is therefore needed to identify loci that confer resistance in the field, i.e., “field blast resistance”. To identify loci associated with field blast resistance (LAFBRs), we conducted a genome-wide association study (GWAS) using the rice diversity panel 1 (RDP1) cultivars. These cultivars were evaluated in the field in three major rice production areas of China.ResultsGWAS identified 16 LAFBRs. Among them, 13 are novel and the other three are co-localized with known blast resistance regions. Seventy-four candidate genes are identified in the 16 LAFBR regions, which encode receptor-like protein kinases, transcription factors, and other defense-related proteins. Using the rice transcriptome data, compared with the rice-rice blast compatible interaction, we identified seven candidate genes that are significantly up-regulated and five genes that are significantly down-regulated in the incompatible interaction among the candidate genes.ConclusionsWe identified 16 LAFBRs involved in field resistance to M. oryzae and 20 cultivars that exhibit high levels of resistance in both the field and growth chamber. The resistant cultivars and the SNP markers identified in this study should be useful for marker-assisted selection of new rice cultivars that confer high levels of resistance against M. oryzae field populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-016-0116-3) contains supplementary material, which is available to authorized users.

The development of efficient red thermally activated delayed fluorescence (TADF) emitters with an emission wavelength beyond 600 nm remains a great challenge for organic light-emitting diodes (OLEDs). Herein, two pairs of isomers are designed and synthesized by attaching electron-donor 9,9-diphenyl-9,10-dihydroacridine (DPAC) moiety to the different positions of two kinds of highly rigid planar acceptor cores (PDCN and PPDCN). Their TADF efficiencies and emission maxima (599-726 nm) are regulated by molecular isomer manipulation. Interestingly, the photoluminescence quantum yields (Φ PL s) of trans-isomers T-DA-1 and T-DA-2 (78% and 89%) are remarkably higher than those of their corresponding cis-isomers C-DA-1 and C-DA-2 (12% and 14%). Significantly increased Φ PL values can be explained by single crystal structures and theoretical simulation. As a result, a deep red TADF-OLED based on T-DA-2 displays a maximum external quantum efficiency (EQE) of 26.26% at 640 nm. Notably, at a brightness of 100 cd m −2 , the EQE value of T-DA-2-based device still remains at an extremely high level of 23.95%, representing the highest value for reported red TADF-OLEDs at the same brightness. These results provide a reasonable pathway to optimize optoelectronic properties and thereby construct efficient red TADF emitters through rational isomer engineering.

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Seismic vulnerability assessments play a significant role in comprehensive risk mitigation efforts and seismic emergency planning, especially for urban areas with a high population density and a complex construction environment. Traditional approaches such as in situ fieldwork are accurate for conducting seismic vulnerability assessments of buildings; however, they are too much time and cost-consuming, especially in moderate to low seismic hazard regions. To address this issue, an integrated approach for a macroseismic vulnerability assessment composed of data mining methods and GIScience technology was presented and applied to Urumqi, China. First, vulnerability proxies were established via in situ data of buildings in the Tianshan District with an EMS-98 vulnerability classification scheme and two data mining methods, namely, support vector machine and association rule learning methods. Then, vulnerability proxies were applied to the Urumqi database, and the accuracy was validated. Finally, seismic risk maps were constructed through data consisting of direct damage to buildings and human casualties. The results indicated that the two data mining methods could achieve desirable accuracies and stabilities when estimating the seismic vulnerability. The seismic risk of Urumqi was estimated as Slight with a predicted number of 61,380 homeless people for a seismic intensity scenario of VIII.

BackgroundUtilization of broad-spectrum resistance (R) genes is an effective and economical strategy to control the fungal pathogen Magnaporthe oryzae, the causal agent of the rice blast disease. Among the cloned blast resistance genes, Pi9, Pi2 and Piz-t confer broad-spectrum resistance to diverse M. oryzae isolates and were isolated from the Pi2/9 locus on chromosome 6. Identification and isolation of additional R genes with different resistance spectra from this locus will provide novel genetic resources for better control of this important rice disease.ResultsIn this study, we identified a dominant R gene, Pi2-2, at the Pi2/9 locus from Jefferson, an elite U.S. rice cultivar, through genetic and physical mapping. Inoculation tests showed that Jefferson has different resistant specificities to M. oryzae isolates compared rice lines with the Pi9, Pi2 and Piz-t genes. Fine mapping delimited Pi2-2 to a 270-kb interval between the markers AP5659-3 and RM19817, and this interval contains three nucleotide-binding site-leucine-rich repeat (NBS-LRR) genes in the Nipponbare genome. Five bacterial artificial chromosome (BAC) clones spanning the region were identified, and a BAC contig covering the Pi2-2 locus was constructed.ConclusionsWe identified a new allelic gene at the Pi2/9 locus and fine-mapped the gene within a 270-kb region. Our results provide essential information for the isolation of the Pi2-2 gene and tightly linked DNA markers for rice blast resistance breeding.Electronic supplementary materialThe online version of this article (doi:10.1186/1939-8433-5-29) contains supplementary material, which is available to authorized users.