Deep-Blue Thermally Activated Delayed Fluorescence Emitters Containing Diphenyl Sulfone Group for Organic Light Emitting Diodes.

Novel blue thermally activated delayed fluorescence (TADF) emitters, D1-DPS and D2-DPS, were designed and synthesized. Diphenyl sulfone (DPS) group functioned as a common acceptor, and it combined with each of two different spiro-acridine groups, D1 and D2. The calculated energy differences (ΔEST) of the singlet and triplet excited states of D1-DPS (0.062 eV) and D2-DPS (0.128 eV) had sufficiently small ΔEST values, which is favorable in the thermally activated reverse intersystem crossing (RISC) process from the T1 state to the S1 state. A device doped 10 wt% of D2-DPS with ADN host material, obtained 5.05% of external quantum efficiency with deep-blue emission having CIExy coordinates of (0.152, 0.065). The results showed that these molecules are promising host-free TADF deep-blue emitters by inhibiting concentration quenching.

Chorea due to diabetic hyperglycemia and uremia: distinct clinical and imaging features.

This study was undertaken to describe the clinical and imaging characteristics of patients with chorea associated with nonketotic hyperglycemia (C-NKH) in comparison with patients with chorea associated with uremia (C-URE). We retrospectively analyzed the clinical data of consecutive 10 C-NKH and five C-URE patients who were treated between January 1, 2001 and January 31, 2013. Women were more frequently affected by C-NKH (70% vs. 30%) and C-URE (80% vs. 20%) compared with men. The C-NKH patients demonstrated T1-hyperintense and inhomogeneous lesions in the basal ganglia, whereas C-URE patients demonstrated T2-hyperintense and homogeneous lesions in the basal ganglia. The mean time for chorea resolution after treatment was significantly shorter in C-NKH patients than in C-URE patients (4.4 ± 2.6 d vs. 73.8 ± 14.2 d, respectively; P = 0.005). The clinical and imaging features are remarkably different between C-NKH and C-URE patients, suggesting distinct pathogenic mechanisms.

Anthracene derivatives with strong spin-orbit coupling and efficient high-lying reverse intersystem crossing beyond the El-Sayed rule.

The attention to materials with hot exciton channel and triplet-triplet fusion (TTF) mediated high-lying reverse intersystem crossing (hRISC) has been raised for their ability to convert non-emissive 'dark' triplets into radiative singlet excitons. This spin conversion process results in high exciton utilization efficiency (EUE) that exceeds the theoretical limits. Notably, it is known that such spin conversion processes from the high-lying excited triplet to the singlet state are facilitated by the orthogonal orbital transition effect governed by the El-Sayed's rule. In this study, an anthracene derivative with indenoquinoline substituent 7,7-dimethyl-9-(10-(4-(naphthalen-1-yl)phenyl)anthracen-9-yl)-7H-indeno[1,2-f]quinoline (2MIQ-NPA) was synthesized and analyzed to investigate whether the hRISC process occurs in these molecules, even when the El-Sayed's rule is not followed. The hRISC channels of the emitter were fully unraveled through DFT calculations and experiments, which were quantitatively subdivided using transient electroluminescence measurements. The results showed that 2MIQ-NPA, which does not follow the El-Sayed's rule and has a relatively strong spin-orbit coupling matrix element of 0.116 cm-1 between the high-lying triplet state of T4 and the lowest singlet state of S1, effectively converted triplet excitons into singlet excitons with an EUE of 64.3%, contributed by a direct hot exciton channel of 19.2% and a TTF-mediated hot exciton channel of 15.1%. Despite the low outcoupling efficiency, the non-doped device with 2MIQ-NPA achieved an excellent device performance with an external quantum efficiency of 7.0%.

Hybridized local and charge transfer dendrimers with near-unity exciton utilization for enabling high-efficiency solution-processed hyperfluorescent OLEDs.

Achieving both high emission efficiency and exciton utilization efficiency (ηS) in hot exciton materials is still a formidable task. Herein, a proof-of-concept design for improving ηS in hot exciton materials is proposed via elaborate regulation of singlet-triplet energy difference, leading to an additional thermally activated delayed fluorescence (TADF) process. Two novel dendrimers, named D-TTT-H and D-TTT-tBu, were prepared and characterized, in which diphenylamine derivatives were used as a donor moiety and tri(triazolo)triazine (TTT) as an acceptor fragment. Compounds D-TTT-H and D-TTT-tBu showed an intense green color with an emission efficiency of approximately 80% in solution. Impressively, both dendrimers simultaneously exhibited a hot exciton process and TADF characteristic in the solid state, as was demonstrated via theoretical calculation, transient photoluminescence, magneto-electroluminescence and transient electroluminescence measurements, thus achieving almost unity ηS. A solution processable organic light-emitting diode (OLED) employing the dendrimer as a dopant represents the best performance with the highest luminance of 15090 cd m-2 and a maximum external quantum efficiency (EQEmax) of 11.96%. Moreover, using D-TTT-H as a sensitizer, an EQEmax of 30.88%, 24.08% and 14.33% were achieved for green, orange and red solution-processed OLEDs, respectively. This research paves a new avenue to construct a fluorescent molecule with high ηS for efficient and stable OLEDs.

High Efficiency of over 25% and Long Device Lifetime of over 500 h at 1000 nit in Blue Fluorescent Organic Light-Emitting Diodes.

In this study, a multiple resonance (MR) type blue emitter is synthesized, characterized, and evaluated for highly efficient and stable blue fluorescent organic light-emitting diodes (OLEDs). The MR blue fluorescent emitter has a di-tert-butyl benzene substituent in the MR core structure to minimize quenching mechanisms by intermolecular interaction. The emitter shows a high photoluminescence quantum yield and small full width at half maximum of 22 nm, which realize high external quantum efficiency (EQE) of 11.4% in the single unit OLED and device lifetime up to 95% of the initial luminance (LT95 ) of 208 h at 1000 cd m-2 and over 10 000 h at 100 cd m-2 . The optimized tandem device of the new blue emitter achieves high EQE over 25% and extremely long LT95 of over 500 h at 1000 cd m-2 and 30 000 h at 100 cd m-2 . The lifetime of this work is one of the best data of blue OLED lifetime reported in the literature.

7,7-Dimethyl-9-(10-phenylanthracen-9-yl)-7H-Benzo[b] Fluoreno[3,4-d]Thiophene Derivatives for Blue Fluorescent Organic Light-Emitting Diodes.

In this study, we designed and synthesized two blue fluorescence materials using 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-benzo[b]fluoreno[3,4-d]thiophene substituted anthracene derivatives. To characterize their electroluminescent properties, we fabricated the OLED devices using these two emitting materials. Particularly, a device using 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7Hbenzo[ b]fluoreno[3,4-d]thiophene showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 2.42 cd/A, 1.48 lm/W, 3.08% at 20 mA/cm2, respectively with CIE (x, y) coordinates of (0.15, 0.09) at 8.0 V.

Highly Efficient 7,7-Dimethyl-9-(10-phenylanthracen-9-yl)-7H-Benzo[6,7]Indeno[1,2-f]Quinoline Derivatives for Blue Fluorescent Organic Light-Emitting Diodes.

Highly efficient blue fluorescent 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7H-benzo[6,7]indeno[1,2- f]quinoline derivatives, based on benzo-indeno-quinoline and phenylanthracene were designed and synthesized. To test their electroluminescent properties, organic light-emitting diodes (OLEDs) were fabricated with the configuration of indium-tin-oxide (ITO) (150 nm)/4,4',4″-Tris[2- naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/N,N'-di(1-naphthyl)-N,N'-diphenyl-1,1'- biphenyl)4,4'-diamine (NPB) (20 nm)/blue emitting materials (20 nm)/bathophenanthroline (Bphen) (30 nm)/Liq (2 nm)/Al (100 nm). The devices using these blue materials as emitters showed efficient blue emission. Particularly, a device employing 7,7-dimethyl-9-(10-phenylanthracen-9-yl)-7Hbenzo[ 6,7]indeno[1,2-f]quinoline as an emitting layer yielded the best performance with a luminous efficiency (LE), power efficiency (PE), and external quantum efficiency (EQE) and the Commission International de L'Eclairge (CIE) coordinates of 4.60 cd/A, 3.07 lm/W, 4.32% at 20 mA/cm², and (0.16, 0.12) at 8.0 V, respectively.

The dependence of enhanced lysosomal activity on the cellular aging of bovine aortic endothelial cells.

Lysosomes are a cell organelle type processing antimicrobial activity. Here, we investigate the lysosomal activity in a primary cell line, bovine aortic endothelial cells (BAECs), during cellular aging, based on the antimicrobial activity of lysosomes isolated from BAECs at cell passages 4, 6, 8, and 10. Cytochemical analysis of lysosomes with LysoTracker reagent revealed the number of lysosome-like organelles surrounding the nucleus initially increased drastically in the BAECs and continued increasing gradually until passage 10. The lysosomes isolated from each successive passage of BAECs exhibited increased antimicrobial activity against Escherichia coli, and, in addition, an age-dependent increase in lysosome intensity coincided with increased lysosomal antimicrobial activity.

Carbon nanotube (CNT)-polymethyl methacrylate (PMMA) composite electrolyte for solid-state dye sensitized solar cells.

A novel carbon nanotube (CNT)-polymethyl methacrylate (PMMA) composite electrolyte was successfully synthesized by the thermal polymerization of methyl methacrylate (MMA) with CNTs for solid-state dye sensitized solar cells (DSSCs). The prepared CNTs-PMMA composite electrolytes were characterized by Fourior transformed-infrared (FT-IR) spectroscopy, field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and ionic conductivity. A strong bonding was observed between CNT and PMMA through ester bonding in the CNT-PMMA composite, resulting in the lowering of crystallinity and increasing the ionic conductivity of composite electrolyte. DSSCs fabricated with CNTs-PMMA composite electrolytes achieved relatively high conversion efficiency of 2.9% with an open circuit voltage (V(oc)) of 0.567 volt, short circuit current (I(sc)) of 8.9 mA/cm2 and fill factor of 61.8%, which is attributed to enhanced amorphicity and ionic conductivity due to the formation of strong bonding between CNT and PMMA molecules.

Cu oxidation kinetics through graphene and its effect on the electrical properties of graphene.

The oxidation kinetics of Cu through graphene were evaluated from the surface coverage of Cu oxide (F ox) by varying the oxidation time (t ox = 10-360 min) and temperature (T ox = 180-240 °C) under an air environment. F ox, as a function of time, well followed the Johnson-Mehl-Avrami-Kolmogorov equation; thus, the activation energy of Cu oxidation was estimated as 1.5 eV. Transmission electron microscopy studies revealed that Cu2O formed on the top of the graphene at grain boundaries (G-GBs), indicating that Cu2O growth was governed by the out-diffusion of Cu through G-GBs. Further, the effect of Cu oxidation on graphene quality was investigated by measuring the electrical properties of graphene after transferring. The variation of the sheet resistance (R s) as a function of t ox at all T ox was converted into one curve as a function of F ox. R s of 250 Ω sq-1 was constant, similar to that of as-grown graphene up to F ox = 15%, and then increased with F ox. The Hall measurement revealed that the carrier concentration remained constant in the entire range of F ox, and R s was solely related to the decrease in the Hall mobility. The variation in Hall mobility was examined according to the graphene percolation probability model, simulating electrical conduction on G-GBs during Cu2O evolution. This model well explains the constant Hall mobility within F ox = 15% and drastic F ox degradation of 15-50% by the concept that the electrical conduction of graphene is disconnected by Cu2O formation along with the G-GBs. Therefore, we systematically developed the oxidation kinetics of Cu through graphene and simultaneously examined the changes in the electrical properties of graphene.

Blue Fluorescent Organic Light-Emitting Diodes Using 11,11-Dimethyl-3-(10-phenylanthracen-9-yl)-11H-Indeno[1,2-b]Quinoline Derivatives.

In this study, we designed and synthesized two blue fluorescence materials using phenylanthracenesubstituted-indenoquinoline derivatives by Suzuki coupling reaction for organic light-emitting diodes (OLEDs). In order to study their electroluminescent properties, we fabricated the OLED devices using these two materials as emissive layer (EML) with the following sequence: indium-tin-oxide (ITO, 180 nm)/4,4',4″-tris[2-naphthyl(phenyl)-amino]triphenylamine (2-TNATA, 30 nm)/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB, 20 nm)/Blue emitting materials (20 nm)/4,7-Diphenyl-1,10-phenanthroline (Bphen, 30 nm)/lithium quinolate (Liq, 2 nm)/Al (100 nm). In particular, a device using 11,11-dimethyl-3-(10-phenylanthracen-9-yl)-11H-Indeno[1,2-b]quinoline in emitting layer showed luminous efficiency, power efficiency, and external quantum efficiency of 2.18 cd/A, 1.10 lm/W, 2.20% at 20 mA/cm², respectively, with Commission Internationale d'Énclairage (CIE) coordinates of (0.15, 0.11) at 8.0 V.

Red Phosphorescent Platinum(II) Complexes with Tetradentate Pyridine-Containing Ligands for Organic Light Emitting Diodes.

Here, red phosphorescent platinum(II) complexes based on tetradentate pyridine-containing lig-ands are studied. To investigate their electroluminescent properties, multilayer devices were fabricated in the following sequence; ITO (180 nm)/4,4',4″-Tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/N, N'-di(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl)4,4'-diamine (NPB) (20 nm)/ Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) (10 nm)/4,4'-Bis(N-carbazolyl)-1,1'-biphenyl (CBP) (20 nm)/Platinum(II) complex (20 nm)/1,3,5-Tris(1-Phenyl-1H-benzimidazol-2-yl)benzene) (TPBi) (40 nm)/Liq (2 nm)/Al (100 nm). In particularly, a device using platinum(II) complex based on N-(3,5-di-tert-butylphenyl)-3-(pyridin-2-yl)-N-(3-(pyridin-2-yl)phenyl)benzenamineligand showed the efficient red emission, with a luminous efficiency, power efficiency, and external quantum efficiency of, and the Commission International de LEclairge (CIE) coordinates of 27.26 cd/A, 10.54 lm/W, 8.50% at 20 mA/cm², and (0.65, 0.33) at 11.0 V, respectively.

Platinum (II) Complexes Based on Tetradentate Pyridine-Containing Ligands for Phosphorescent Organic Light-Emitting Diodes.

In this study, we designed and synthesized two phosphorescent emitting materials based on tetradentate pyridine-containing ligands. Their photophysical properties were examined for OLEDs and multilayer devices using these materials were fabricated in the following sequence; ITO (180 nm)/4,4',4″-Tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) (30 nm)/N,N'-di(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl)4,4'-diamine (NPB) (20 nm)/Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) (10 nm)/4,4'-Bis(N-carbazolyl)-1,1'-biphenyl(CBP): 5, 8, 15% Platinum (II) complexes (20 nm)/1,3,5-Tris(1-Phenyl-1H-benzimidazol-2-yl)benzene) (TPBi) (40 nm)/Liq (2 nm)/Al (100 nm). In particularly, a device using Platinum (II) complex based on A/-(3,5-di-tert-butylphenyl)-6-phenyl-N-(6-phenylpyridin-2-yl)pyridin-2-amine ligand showed the efficient emission, with luminous efficiency, power efficiency, and external quantum efficiency, and the Commission International de LEclairge (CIE) coordinates of 29.29 cd/A, 9.37 lm/W, 8.66% at 20 mA/cm2, and (0.32, 0.62) at 8.0 V, respectively.

Comparison of Growth Behavior and Electrical Properties of Graphene Grown on Solid and Liquid Copper by Chemical Vapor Deposition.

We study the graphene growth behavior above and below the copper (Cu) melting point (1083 °C) by only changing the growth temperature from 1020 °C to 1100 °C at intervals of 40 °C, to investigate the effect of the Cu phase as a catalyst layer in graphene growth. We investigate the graphene growth behavior by observing the changes in nucleation density and grain size with growth time. As the phase of the Cu catalyst changes from solid to liquid, the grain size of graphene increases by 2 orders of magnitude from 0.4 to 40 µm, while the nuclei density decreases by 4 orders of magnitude from 3.02/µm2 to 0.0004/µm2. Additionally, as in previous studies, graphene growth shows a well-aligned hexagonal shape on liquid Cu although graphene on solid Cu shows an irregular shape under the same growth conditions. The effect of the smooth surface of the liquid metal catalyst on graphene growth is remarkable even after considering the temperature difference. The reduction of defect density arising from the increase of the graphene grain size is confirmed by Raman spectroscopy. Additionally, the improvement in electrical properties is also investigated by Hall measurements.

Antimicrobial activity of the cell organelles, lysosomes isolated from egg white.

Lysosomes as a cell organelle type, are safe biological control agents that may be possible replacements for chemical antimicrobial agents because they are simply isolated from egg white. In this study, it was found that the lysosomes isolated from egg white exhibited pH-dependent antimicrobial activity with the optimal activity found at pH 6.0. The efficiency of lysosomes in inhibiting bacterial growth and activity was evaluated over a 12-hour treatment period. Seven different microorganisms were used as bacterial strains, and the lysosomes showed a significant antimicrobial effect against all strains. In addition, the antimicrobial activity was maintained for 100 days, and there did not appear to be any resistance of E. coli to the lysosomal activity up to eighth culture. However, the lysosomes did not affect the viability of mammalian cells, suggesting the biocompatibility of lysosomes. These highly effective lysosomes have a bright future in the application of novel antimicrobial sources as a cell organelle type.

Central Obesity as a Risk Factor for Non-Erosive Reflux Disease.

PURPOSE: Although central obesity is a risk factor for erosive esophagitis, information regarding the association between central obesity and non-erosive reflux disease (NERD) is still scarce. The purpose of this study was to investigate the risk factors for NERD by comparing NERD patients and healthy controls. MATERIALS AND METHODS: Comprehensive clinical data from 378 patients who underwent esophagogastroduodenoscopy from December 2012 to May 2013 and had no visible esophageal mucosal breakage were analyzed. The Korean version of GerdQ questionnaire was used to diagnose NERD. The association between central obesity and NERD was assessed after matching subjects according to propensity scores. RESULTS: There were 119 NERD patients and 259 controls. In multivariate analysis, central obesity, female gender, and younger age were significantly associated with NERD [odds ratio (OR)=2.55, 1.93, and 1.80; p=0.001, 0.005, and 0.011, respectively]. After adjusting for 12 clinical variables using propensity score matching, 114 NERD patients were matched to 114 controls. All variables were well balanced between the two groups (average D before matching: 0.248, after matching: 0.066). Patients with NERD were more likely to have central obesity than healthy controls (28.1% vs. 7.9%). After adjusting for propensity scores and all covariates in multivariable logistic regression analyses, central obesity was still found to be a significant risk factor for NERD (OR=4.55, p<0.001). CONCLUSION: Central obesity appears to be an independent risk factor for NERD. This result supports the presence of an association between GERD and central obesity, even in the absence of esophageal erosion (NERD).

Association of Poor Differentiation or Positive Vertical Margin with Residual Disease in Patients with Subsequent Colectomy after Complete Macroscopic Endoscopic Resection of Early Colorectal Cancer.

In the presence of unfavorable pathologic results after endoscopic resection of colorectal cancer, colectomy is routinely performed. We determined the risk factors for residual diseases in patients with colectomy after complete macroscopic endoscopic resection of early colorectal cancer. We identified consecutive patients who underwent endoscopic resection of early colorectal cancer and subsequently underwent colectomy, from January 2011 to December 2014. Clinicopathologic risk factors related to the residual disease were analyzed. In total, 148 patients underwent endoscopic resection and subsequent colectomy. Residual disease on colectomy was noted in 16 (10.9%) patients. The rates of poorly differentiated/mucinous histology (p = 0.028) and of positive or unknown vertical resection margin (p = 0.047) were higher in patients with residual disease than in those without. In multivariate analysis, a poorly differentiated/mucinous histology and positive or unknown vertical resection margin were significantly associated with residual disease (odds ratio = 7.508 and 2.048, p = 0.015 and 0.049, resp.). After complete macroscopic endoscopic resection of early colorectal cancer, there is a greater need for additional colectomy in cases with a positive or unknown vertical resection margin or a poorly differentiated/mucinous histology, because of their higher risk of residual cancer and lymph node metastasis.

High and Frequent Dose of Dexlansoprazole and Amoxicillin Dual Therapy for Helicobacter pylori Infections: A Single Arm Prospective Study.

BACKGROUND/AIMS: Recently, the eradication rate of Helicobacter pylori (H. pylori) infection has decreased to less than 80% worldwide with the use of clarithromycin-based triple therapy owing to the increased resistance of H. pylori to antibiotics, especially clarithromycin and metronidazole. This prospective study aimed to determine eradication rate of H. pylori following high and frequent doses of extended-release dexlansoprazole and amoxicillin, as a dual therapy in a region with high clarithromycin resistance rate. METHODS: A total of 50 treatment-naïve patients with active H. pylori infections, who were confirmed through via rapid urease test or histology and serology between November 2015 and February 2016 at our hospital, were included for analysis. All enrolled patients were treated with 750 mg amoxicillin and 30 mg dexlansoprazole, four times a day for a total duration of 14 days. Treatment success was determined using urea breath test four weeks after treatment completion. RESULTS: Seven out of the 50 patients (29 men and 21 women; mean age, 57 years) dropped out during the study. The total eradication rate was 52% (26/50), and that for those with a compliance rate of over 90% was 68.4% (26/38). H. pylori infections were not successfully eradicated in patients with a compliance rate of less than 90%. Nine patients (18%) reported side effects, such as mild diarrhea and abdominal fullness. No significant factors, such as smoking and alcohol consumption, affected the infection the eradication rate. CONCLUSIONS: High and frequent doses of proton pump inhibitor-amoxicillin dual therapy were not effective in eradicating H. pylori infection in a province with high clarithromycin resistance rate.

Highly Stable and Effective Doping of Graphene by Selective Atomic Layer Deposition of Ruthenium.

The sheet resistance of graphene synthesized by chemical vapor deposition is found to be significantly reduced by the selective atomic layer deposition (ALD) of Ru onto defect sites such as wrinkles and grain boundaries. With 200 ALD cycles, the sheet resistance is reduced from ∼500 to <50 Ω/sq, and the p-type carrier density is drastically increased from 1013 to 1015 cm-2. At the same time, the carrier mobility is reduced from ∼670 to less than 100 cm2 V-1 s-1. This doping of graphene proved to be very stable, with the electrical properties remaining unchanged over eight weeks of measurement. Selective deposition of Ru on defect sites also makes it possible to obtain a graphene film that is both highly transparent and electrically conductive (e.g., a sheet resistance of 125 Ω/sq with 92% optical transmittance at 550 nm). Highly doped graphene layers achieved by Ru ALD are therefore expected to provide a viable basis for transparent conducting electrodes.

[Actinomycosis Involving Chronic Pancreatitis: A Case Report with Literature Review].

Actinomycosis is a slowly progressive, chronic infectious disease. It is caused by the genus Actinomyces, which are gram-positive anaerobic bacteria. It presents as a mass-like lesion, composed of bacterial nidus and characteristic granulomatous inflammatory fibrosis. As such, it has frequently been mistaken for a malignancy. Surgical resection is a common procedure in these patients prior to a definite diagnosis. Although actinomycosis can occur in a variety of regions, including oral-cervicofacial, thoracic, and abdominopelvic cavities, the involvement of the pancreas is very rare. We report a case of a 44-year-old male with a symptomatic actinomycosis caused by a mass in the tail of the pancreas. The diagnosis was made using an endoscopic ultrasound-guided fine needle aspiration biopsy without surgical resection. After the treatment with antibiotics, the pancreatic mass was confirmed to be resolved on the follow-up computed tomography.