Indenophenanthrene Derivatives for Highly Efficient Blue Organic Light-Emitting Diodes.

In this study, we designed and synthesized three fluorescent blue emitting materials based on indenophenanthrene derivatives. These derivatives were synthesized by Suzuki coupling reaction. Particularly, a device C using 9,10-bis(9,9-dimethyl-9H-indeno[2,1-l]phenanthren-11-yl)anthracene as blue emitter showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 7.58 cd/A, 5.87 lm/W, 4.20%, respectively.

Diphenylaminoarylvinyl-Substituted Diphenylanthracenes for Organic Light-Emitting Diodes.

Two blue fluorescent materials based on diphenylaminoarylvinyl-substituted diphenylanthracene have been synthesized. Multilayered organic light-emitting diodes (OLED) with the following sequence; ITO/NPB (50 nm)/Blue materials (30 nm)/Bphen (30 nm)/Liq (2 nm)/Al (100 nm) were fabricated using these materials as emitters. Two devices exhibited blue electroluminescence. Particularly, a device using 6-(4-(10-phenylanthracen-9-yl)styryl)-N,N-diphenylnaphthalen-2-amine (2) exhibited blue emission with a luminance efficiency, a power efficiency, an external quantum efficiency and CIE coordinates of 5.69 cd/A, 1.99 lm/W, 3.39% at 100 mA/cm² and (x = 0.19, y =0.31) at 8.0 V, respectively.

Highly Efficient Blue Organic Light-Emitting Diodes Based on Diarylamine-Substituted Pyrene Derivatives.

In this study, we designed and synthesized three blue fluorescence materials based on diarylamine-substituted pyrene derivatives. Organic Light Emitting-Diodes devices using these materials were fabricated in the following sequence; ITO/2-TNATA (300 Å)/NPB (200 Å)/α,ß-ADN: 10 wt% blue materials 1-3 (300 Å)/DNAB (300 Å)/Liq (20 Å)/Al (1000 Å). All devices showed highly efficient blue emissions. Particularly, a device using materials (3) shown highly efficient blue emission with luminous efficiency of 8.94 cd/A, power efficiency of 4.40 lm/W, external quantum efficiency of 6.62% at 20 mA/cm², respectively, and the CIE coordinates of (0.16, 0.23) at 6.0 V.

Highly Efficient Organic Light-Emitting Diodes Based on Naphthoanthracene Derivatives Containing Different Arylamines.

Herein, we designed and synthesized emitting materials based on naphthoanthracene with the different arylamino-substituents. Organic Light Emitting-Diodes (OLEDs) devices using these materials were fabricated in the following sequence; ITO/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'- diamine (NPB) (500 Å)/Emitters (400 Å)/Alumium quinolate (Alq3) (150 Å)/lithium quinolate (Liq) (20 Å)/Al (1000 Å). All devices showed efficient emissions. In particular, a device using 4-((5,5-dimethyl-9-phenyl-5H-naphtho[3,2,1-de]anthracen-3-yl)(phenyl)amino)benzonitrile as an emitter exhibited the luminous efficiency, power efficiency, and external quantum efficiency of 9.15 cd/A, 6.36 lm/W, 2.72% at 20 mA/cm², respectively, with the Commission Internationale d'Énclairage (CIE) coordinates of (0.30, 0.62) at 6.0 V.

Synthesis of Benzo[g]quinoline Derivatives and Their Electroluminescent Properties.

Two fluorescent benzo[g]quinoline derivatives were synthesized via Friedländer synthesis. Multilayered OLEDs using benzo[g]quinoline derivatives as the emitters showed unexpected emissions by electroplexes. Particularly, a device using 2-(naphthalen-3-yl)-4-phenylbenzo[g]quinoline as an emitting material exhibited efficient emission with a luminous efficiency, a power efficiency, an external quantum efficiency, and CIE coordinates of 3.58 cd/A, 1.11 lm/W, 1.08% at 20 mA/cm², and (0.36, 0.56) at 1,000 cd/m², respectively.

Fabrication of Blue Organic Light-Emitting Diodes Based on Indeno-Phenanthrene/Triphenylene Amine Derivatives.

Among the three primary colors, blue-emitting materials are limited by the wide energy band gap. In this study, we designed and synthesized emitting materials based on indeno-phenanthrene/ triphenylene derivatives. Organic light emitting-diodes (OLEDs) using these materials were fabricated in the following sequence; ITO/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (500 Å)/Blue materials (30 nm)/4,7-diphenyl-1,10-phenanthroline (BPhen) (30 nm)/lithium quinolate (Liq) (20 Å)/Al (1000 Å). All the devices showed efficient blue emission. Particularly, a device using 10,10-dimethyl-N,N-diphenyl-10H-indeno[1,2-b]triphenylen-12-amine as an emitter exhibited luminous efficiency, power efficiency, and external quantum efficiency of 3.62 cd/A, 1.83 lm/W, 2.82% at 20 mA/cm², respectively, with Commission Internationale d'Énclairage (CIE) coordinates of (0.16, 0.15) at 6.0 V.

Naphthalene Derivatives End-Capped with 2-(Diphenylamino)-9,9-Diethylfluorenes for Blue Organic Light-Emitting Diodes.

To investigate the electroluminescent (EL) properties of fluorescent materials based on fluorene-substituted naphthalene, multilayered OLEDs with the following sequence; indium- tin-oxide (ITO)/N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) (50 nm)/Blue emitting materials (30 nm)/4,7-diphenyl-1,10-phenanthroline (Bphen) (30 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm) were fabricated using these materials as emitters. These devices exhibited blue emissions. Particularly, a device using 7-(1-(1-(2-(diphenylamino)-9,9-diethyl-9H-fluoren-7- yl)naphthalen-4-yl)naphthalen-4-yl)-9,9-diethyl-N,N-diphenyl-9H-fluoren-2-amine as a blue emitting material exhibited blue emission with a luminous efficiency, a power efficiency, an external quantum efficiency, and CIE coordinates of 2.79 cd/A, 1.19 lm/W, 2.30% at 1,000 cd/m2, and (0.14, 0.12) at 8.0 V, respectively. This study demonstrates that 2-(Diphenylamino)-9,9-diethylfluorenes endcapped naphthalene derivatives have the excellent properties for blue emitting materials for OLEDs.

Synthesis and Electroluminescent Properties of Quinoline-Substituted Anthracene Derivatives for Organic Light-Emitting Diodes.

In this study, two anthracene derivatives with quinoline moieties were synthesized. To investigate their electroluminescent (EL) properties, multilayered OLEDs with the following sequence; indiumtin-oxide (ITO)/N, N'-di(1-naphthyl)-N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) (20 nm)/Blue emitting materials (30 nm)/bathophenanthroline (Bphen) (30 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm) were fabricated using these materials as emitters. Two devices exhibited EL in blue to sky-blue regions. Especially, a device using 2,3-diphenyl-6-(10-(naphthalen-7-yl)anthracen-9-yl)quinoline (1) as an emitting material exhibited blue emission with a luminous efficiency, a power efficiency, an external quantum efficiency, and Commission International de L'Eclairage (CIE) coordinates of 1.01 cd/A, 0.43 lm/W, 0.80% at 20 mA/cm2, and (0.17, 0.22) at 6.0 V, respectively.

Efficient Organic Light-Emitting Diodes Based on Naphthoanthracene Derivatives.

In this study, we designed and synthesized emitting materials based on naphthoanthracene derivatives. Organic Light Emitting-Diodes (OLEDs) devices using each four materials were fabricated. All devices showed efficient emissions. In particular, a device using 1-(5,5-Dimethyl-9-phenyl-[5H-naphth[3,2,1-de]anthracen-3-yl])-1H-indole as an emitter at 20 mA/cm2 exhibited luminous efficiency, power efficiency, and external quantum efficiency of 6.51 cd/A, 4.19 lm/W, and 2.48%, respectively, with Commission Internationale d'Énclairage (CIE) coordinates of (0.19, 0.49) at 7.0 V.

Optimum thickness of epsilon negative tri-metal layer electrodes for maximizing OLED outcoupling efficiency.

A transparent electrode is an essential component that has a strong influence on the extraction of light from organic light-emitting diodes (OLEDs) due to its effect on both electrical and optical performance. In this work, we present theoretical studies, full wave simulations, and experimental results to evaluate the influence of the thickness of epsilon negative tri-metal layer (TML) electrodes on the performance of red phosphorescent OLEDs (PHOLEDs) via an optical microcavity effect. The results show that the external quantum efficiency of the optimized TML-based red PHOLED of 17.6% is significantly improved, and it is approximately 40% higher than that of the conventional indium tin oxide (ITO)-based red PHOLED of 12.5%.

Blue organic light-emitting diodes based on fluorene-bridged quinazoline and quinoxaline derivatives.

Two blue emitters based on fluorene-bridged quinazoline and quinoxaline derivatives were prepared via the Suzuki reaction. Their photoluminescent properties were investigated. Furthermore, theoretical studies on these materials using the density functional theory calculation were conducted. To explore their electroluminescent properties, multilayered organic light-emitting diodes were fabricated with the following device structure: indium-tin-oxide (180 nm)/4,4'-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (50 nm)/blue emitting materials (1 and 2) (30 nm)/bathophenanthroline (35 nm)/8-hydroxy-quinolinato lithium (2 nm)/Al (100 nm). Two devices showed efficient blue emission with the external quantum efficiencies of 1.58% and 1.30%, respectively, at 20 mA/cm2 , and Commission Internationale dÉclairage coordinates of (0.18, 0.24) and (0.19, 0.27) at 6.0 V. These results suggest that the self-aggregation properties of emitters would have considerable effects on their photoluminescent and electroluminescent properties.

Runx1 and p21 synergistically limit the extent of hair follicle stem cell quiescence in vivo.

Mechanisms of tissue stem cell (SC) quiescence control are important for normal homeostasis and for preventing cancer. Cyclin-dependent kinase inhibitors (CDKis) are known inhibitors of cell cycle progression. We document CDKis expression in vivo during hair follicle stem cell (HFSC) homeostasis and find p21 (cyclin-dependent kinase inhibitor 1a, Cdkn1a), p57, and p15 up-regulated at quiescence onset. p21 appears important for HFSC timely onset of quiescence. Conversely, we find that Runx1 (runt related transcription factor 1), which is known for promoting HFSC proliferation, represses p21, p27, p57, and p15 transcription in HFSC in vivo. Intriguingly, in cell culture, tumors, and normal homeostasis, Runx1 and p21 interplay modulates proliferation in opposing directions under the different conditions. Unexpectedly, Runx1 and p21 synergistically limit the extent of HFSC quiescence in vivo, which antagonizes the role of p21 as a cell cycle inhibitor. Importantly, we find in cultured keratinocytes that Runx1 and p21 bind to the p15 promoter and synergistically repress p15 mRNA transcription, thereby restraining cell cycle arrest. This documents a surprising ability of a CDKi (p21) to act as a direct transcriptional repressor of another CDKi (p15). We unveil a robust in vivo mechanism that enforces quiescence of HFSCs, and a context-dependent role of a CDKi (p21) to limit quiescence of SCs, potentially by directly down-regulating mRNA levels of (an)other CDKi(s).

Efficient blue organic light-emitting diodes using N(2) ,N(2) ,N(11) ,N(11) ,5,6,7,8-octaphenyltriphenylene-2,11-diamine derivatives.

In this study, we have synthesized phenyl-substituted triphenylene derivatives, using the Diels-Alder reaction and the Buchwald-Hartwig reaction. To investigate electroluminescence properties of these materials, multilayer organic light-emitting diode (OLED) devices were fabricated with a structure of indium-tin-oxide (ITO) (180 nm)/4,4'-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) (50 nm)/blue-emitting materials (1-3) (30 nm)/bathophenanthroline (Bphen) (35 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). A device using N(2) ,N(2) ,N(11) ,N(11) ,5,6,7-heptaphenyltriphenylene-2,11-diamine (2) exhibited efficient blue emission with luminous, power, and external quantum efficiencies of 0.92 cd/A, 0.67 lm/W, and 1.17% at 20 mA/cm(2) , respectively. The Commission International de L'Éclairage coordinates of this device were (x = 0.15, y = 0.09) at 6.0 V. Copyright © 2015 John Wiley & Sons, Ltd.

Effect of Stepwise Doping on Lifetime and Efficiency of Blue and White Phosphorescent Organic Light Emitting Diodes.

We investigated a light emission mechanism of blue phosphorescent organic light emitting diodes (PHOLEDs), using a stepwise doping profile of 2, 8, and 14 wt.% within the emitting layer (EML). We fabricated several blue PHOLEDs with phosphorescent blue emitter iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C2]picolinate doped in N,N'-dicarbazolyl-3,5-benzene as a p-type host material. A blue PHOLED with the highest doping concentration as part of the EML close to an electron transporting layer showed a maximum luminous efficiency of 20.74 cd/A, and a maximum external quantum efficiency of 10.52%. This can be explained by effective electron injection through a highly doped EML side. Additionally, a white OLED based on the doping profile was fabricated with two thin red EMLs within a blue EML maintaining a thickness of 30 nm for the entire EML. Keywords: Blue Phosphorescent Organic Light Emitting Diodes, Stepwise Doping Structure, Charge Trapping Effect.

Klebsiella pneumoniae K1 liver abscess and septic endophthalmitis in a U.S. resident.

Klebsiella pneumoniae K1 is a major agent of hepatic abscess with metastatic disease in East Asia, with sporadic reports originating elsewhere. We report a case of abscess complicated by septic endophthalmitis caused by a wzyAKpK1-positive Klebsiella strain in a U.S. resident, raising concern for global emergence.

Efficient green phosphorescent organic light-emitting diodes depending on concentration of lithium quinolate in electron transport layer.

Systematic studies on carrier injection and transport are very important for achieving high efficiency in OLEDs. We demonstrate excellent green phosphorescent organic light-emitting diodes (OLED) with lithium quinolate (Liq) doped in 1,3,5-tris(N-phenylbenzimidazole-2-yl) benzene (TPBi) as the electron transport layer (ETL). The doping concentration of Liq was varied from 0% to 10%. The optimized green phosphorescent OLED with 5% Liq in the ETL showed the best efficiencies, which were maximum luminous efficiency, power efficiency, and quantum efficiency of 65.76 cd/A, 57.39 Im/W, and 20.03%, respectively. Moreover, high triplet energy states of TCTA and TPBi as a triplet exciton-blocking layer (TEBL) played a role in efficient exciton confinement.

Regulation of mouse steroidogenesis by WHISTLE and JMJD1C through histone methylation balance.

The dynamic exchange of histone lysine methylation status by histone methyltransferases and demethylases has been previously implicated as an important factor in chromatin structure and transcriptional regulation. Using immunoaffinity TAP analysis, we purified the WHISTLE-interacting protein complexes, which include the heat shock protein HSP90α and the jumonji C-domain harboring the histone demethylase JMJD1C. In this study, we demonstrate that JMJD1C specifically demethylates histone H3K9 mono- and di-methylation, and mediates transcriptional activation. We also provide evidence suggesting that both WHISTLE and JMJD1C performs functions in the development of mouse testes by regulating the expression of the steroidogenesis marker, p450c17, via SF-1-mediated transcription. Furthermore, we demonstrate that WHISTLE is recruited to the p450c17 promoter via SF-1 and represses the transcription of prepubertal stages of steroidogenesis, after which JMJD1C replaces WHISTLE and activates the expression of target genes via SF-1-mediated interactions. Our results demonstrate that the histone methylation balance mediated by HMTase WHISTLE and demethylase JMJD1C perform a transcriptional regulatory function in mouse testis development.

Glycoprotein 90K, downregulated in advanced colorectal cancer tissues, interacts with CD9/CD82 and suppresses the Wnt/beta-catenin signal via ISGylation of beta-catenin.

BACKGROUND AND AIMS: 90K, a tumour-associated glycoprotein, interacts with galectins and has roles in host defence by augmenting the immune response, but the serum 90K level was suggested to indicate poor prognosis in several cancers. The cellular mechanisms of 90K action on colorectal cancer (CRC) cell motility and its effect on CRC progression were investigated. METHODS: The impact of 90K was analysed by combining cell cultures, in vitro assays, and immunohistochemistry. RESULTS: Secreted 90K suppresses CRC cell invasion, but this action of 90K is masked through binding with extracellular galectins. A novel pathway is identified comprising a secretory 90K and a CD9/CD82 tetraspanin web; in this pathway, 90K interacts with CD9/CD82, suppresses the Wnt/beta-catenin signal via a novel proteasomal-ubiquitination mechanism of beta-catenin that is dependent on ISG15 (interferon-stimulated gene-15) modification (ISGylation) but not on glycogen synthase kinase 3beta (GSK-3beta) and Siah/Adenomatous polyposis coli (APC). In a syngeneic mouse colon tumour model, tumour growth and lung metastasis were increased with 90K knockdown. In colon tissues from stage IV human CRC and invading cancer cells of corresponding metastatic liver tissues, in which beta-catenin and galectin expression was higher, immunostained 90K and CD9/CD82 were lower than in adjacent hepatic tissues or colon tissues from stage I. CONCLUSIONS: 90K itself has antitumour activity in CRC cells via suppression of Wnt signalling with a novel mechanism of ISGylation-dependent ubiquitination of beta-catenin when it interacts with CD9/CD82, but is downregulated in advanced CRC tissues. The data suggest a strategy of strengthening this novel pathway with concomitant knockdown of galectins as a potential therapeutic approach to CRC progression.

Ultrastructural features of retinal capillary basement membrane thickening in diabetic swine.

PURPOSE: To assess retinal capillary basement membrane thickening (BMT) in a swine model of type 1 diabetes. MATERIALS AND METHODS: Yorkshire pigs were rendered diabetic with streptozotocin and dyslipidemic with a high fat and cholesterol diet. At 18, 26, and 32 weeks of diabetes, the retina sections within 3 disc diameters from the optic disc were examined under transmission electron microscopy to evaluate the ultrastructural features of the capillary BM. Digital morphometric analysis was performed to measure BMT. RESULTS: Diabetic swine had significantly thicker retinal capillary BMs compared to controls. Pigs that sustained diabetes for longer periods or experienced severe diabetes tended to have more BMT. Those pigs that did not sustain glucose levels above 200 mg/dL did not demonstrate thicker retinal capillary BMs. Characteristic ultrastructural features of diabetic vasculopathy observed included rarefaction as an early stage of Swiss cheese cavitation, lamellation with multiplication of electron dense layers, and fibrillar materials within capillary BM. CONCLUSIONS: Diabetic Yorkshire pigs develop characteristic features of an early retinal microvasculopathy fairly rapidly and may serve as a higher-order animal model for studies of type 1 diabetes.

Studies on Organic Light Emitting Diodes Using Phenanthroline Derivatives as Emitters.

In this study, we designed and synthesized blue emitting materials based on 1, 10-phenanthroline derivatives. OLED devices using these materials were fabricated in the following sequence; indium-tin-oxide (ITO) (180 nm)/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (50 nm)/Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) (10 nm)/Blue materials (20 nm)/2,2',2″-(1,3, 5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) (30 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). Particularly, a device using 2-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-1-phenyl-1Himidazo[ 4,5-f][1,10] phenanthroline as a blue emitter showed the maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 1.45 cd/A, 1.52 lm/W, 0.99%, respectively with the Commission Internationale d'Énclairage (CIE) (x,y) coordinates of (0.16, 0.14) at 8.0 V.