High-Performance Flexible Organic Light-Emitting Diodes Using Amorphous Indium Zinc Oxide Anode

We demonstrate a high-performance flexible organic light-emitting diode (OLED) employing amorphous indium zinc oxide (IZO) anode. The amorphous IZO on flexible polycarbonate (PC) substrate shows similar electrical conductivity and optical transmittance with commercial (ITO) glass, even though it was prepared at <50°C. Moreover, it exhibits little resistance change during 5000 bending cycles, demonstrating good mechanical robustness. A green phosphorescent OLED fabricated on amorphous IZO on flexible PC shows maximum external quantum efficiency of ext=13.7% and power efficiency of p=32.7 lm/W, which are higher than a device fabricated on a commercial ITO on glass (ext=12.4% and p=30.1 lm/W) and ITO on flexible PC (ext=8.5% and p =14.1 lm/W). The mechanical robustness and low-temperature deposition of IZO combined with high OLED performance clearly manifest that the amorphous IZO is a promising anode material for flexible displays.This work was supported by the Ministry of Commerce, Industry, and Energy through the OLED center and Samsung SDI. H.K.K. thanks the Korea Research Foundation (contract no. KRF-2006-331- D00243) for its support

Transparent Conducting Indium Zinc Tin Oxide Anode for Highly Efficient Phosphorescent Organic Light Emitting Diodes

The preparation and characteristics of a transparent conducting indium zinc tin oxide (IZTO) anode for highly efficient phosphorescent organic light emitting diodes (OLEDs) is described. The resistivity and transmittance of the IZTO anode are comparable to reference In2O3 (ITO) anode films even though it was prepared at room temperature. In addition, the work function of the ozone-treated amorphous IZTO anode (5.12±0.02 eV) is much higher than that of ozone-treated reference ITO anodes (4.94±0.02 eV). The current-voltage-luminance characteristics and efficiencies of OLEDs prepared on the IZTO anode are critically dependent on the sheet resistance of the IZTO anode. Furthermore, both the quantum efficiency and power efficiency of the OLED fabricated on the amorphous IZTO anode are much higher than those of an OLED with the reference ITO anode due to the higher work function of the IZTO anode than those of conventional ITO anode. This indicates that IZTO is an alternative material for conventional ITO anodes used in OLEDs and flexible displays.This work was supported by a Korea Research Foundation Grant funded by the Korea Government MOEHRD: Basic Research Promotion Fund grant no. KRF-2006-331-D00243 and the Ministry of Commerce, Industry, and Energy

Inhalation toxicity of humidifier disinfectants as a risk factor of children’s interstitial lung disease in Korea: a case-control study

Abstract Background: The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD

Propeties of the Relativistic Terahertz Radiation from the Perturbed Underdense Plasma

We investigated properties of the relativistic terahertz radiation from an underdense plasma perturbation that is induced by high-power fs laser. In particular, this study is focused on the effect of relativistic Lorentz factor on the radiation frequency, for which extensive PIC (particle-in-cell) simulations were performed. In addition, the possibility of tuneable and controllable spectrum generation by interactions of an intense laser beam and a plasma was studied. In this poster, the theoretical and simulation results are presented

Controlling the spectrum of high-power terahertz radiation from a laser-driven plasma wave

Generation of strong THz waves is a very important and difficult research issue. We performed particle-in-cell (PIC) simulation studies to investigate the possibility of powerful THz generation and spectrum controllability by using a laser-driven plasma wave. Our results show that it is possible to produce spectrum-controllable high-power (>1 MV/cm) THz waves by manipulating the plasma density profiles. This method may provide a good way for coherent high-power THz radiation sources, of which the spectrum ranges from a narrow bandwidth to a wide bandwidth.close0

Wireless Power Transfer Based Implantable Neurostimulator

In this paper, we developed a miniaturized Wireless Power Transfer (WPT) based implantable stimulator that can deliver electrical energy directly to peripheral nerves using electromagnetic induction between internal and external coils. The WPT system was designed to reduce the sensitivity of alignment and increase the efficiency considering the properties of human body tissues and the implantable devices. The received electrical signals at the receiving coil are rectified by the rectifying circuit and harvested in the capacitor to turn on the pulse generating system. This creates constant monophasic rectangular pulses to stimulate nerves through the electrodes without any high specification components such as a programmable microcontroller unit (MCU). An animal study using a rat model was performed to demonstrate that the device encapsulated in a small size of 8mm x 8mm x 3mm using WPT can produce motor output by stimulating nerves.11Nsciescopu

Preliminary Validation of a Continuum Model for Dimple Patterns on Polyethylene Naphthalate via Ar Ion Beam Sputtering

This work reports the self-organization of dimple nanostructures on a polyethylene naphthalate (PEN) surface where an Ar ion beam was irradiated at an ion energy of 600 eV. The peak-to-peak roughness and diameter of dimple nanostructures were 29.1~53.4 nm and 63.4~77.6 nm, respectively. The electron energy loss spectrum at the peaks and troughs of dimples showed similar C=C, C=O, and O=CH bonding statuses. In addition, wide-angle X-ray scattering showed that Ar ion beam irradiation did not induce crystallization of the PEN surface. That meant that the self-organization on the PEN surface could be due to the ion-induced surface instability of the amorphous layer and not due to the partial crystallinity differences of the peaks and valleys. A nonlinear continuum model described surface instability due to Ar ion-induced sputtering. The Kuramoto–Sivashinsky model reproduced the dimple morphologies numerically, which was similar to the experimentally observed dimple patterns. This preliminary validation showed the possibility that the continuum equation used for metal and semiconductor surfaces could be applied to polymer surfaces where ion beam sputtering occurred

Sequestration of synaptic proteins by alpha-synuclein aggregates leading to neurotoxicity is inhibited by small peptide

<div><p>α-Synuclein (α-syn) is a major component of Lewy bodies found in synucleinopathies including Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB). Under the pathological conditions, α-syn tends to generate a diverse form of aggregates showing toxicity to neuronal cells and able to transmit across cells. However, mechanisms by which α-syn aggregates affect cytotoxicity in neurons have not been fully elucidated. Here we report that α-syn aggregates preferentially sequester specific synaptic proteins such as vesicle-associated membrane protein 2 (VAMP2) and synaptosomal-associated protein 25 (SNAP25) through direct binding which is resistant to SDS. The sequestration effect of α-syn aggregates was shown in a cell-free system, cultured primary neurons, and PD mouse model. Furthermore, we identified a specific blocking peptide derived from VAMP2 which partially inhibited the sequestration by α-syn aggregates and contributed to reduced neurotoxicity. These results provide a mechanism of neurotoxicity mediated by α-syn aggregates and suggest that the blocking peptide interfering with the pathological role of α-syn aggregates could be useful for designing a potential therapeutic drug for the treatment of PD.</p></div

α-Syn aggregates from PD mouse model directly bind to VAMP2 <i>in vivo</i>.

<p>(A) Immunohistochemistry of basal ganglia from 22 months old SNCA mouse brain. Multiple α-syn aggregates (distinct red signals in the upper right panel) are shown in the old SNCA mouse brain and one of the aggregates (white boxed inset) is shown at a high magnification 3-dimensional image in the middle panels. Two lateral section images crossed in white dotted lines (a and b from the middle right panel) are displayed in the bottom panels. The arrowheads in white indicate the clustered VAMP2 in the α-syn aggregates. Scale bars (upper panels; 100 µm, middle and lower panels; 20 µm) (B) Young (3 months) and old (22 months) SNCA mice brain tissue lysates were subjected to immunoprecipitation using VAMP2 antibody followed by immunoblot using α-syn antibody. Oligomer species were increased in old SNCA mice brain (marked in bracket) and high molecular weight oligomer (marked an asterisk) was detected only in the old mice. Immunoblot of VAMP2 was used as loading control. Immunoblot is a representative blot from two independent experiments.</p