Nanostructural Effect of ZnO on Light Extraction Efficiency of Near-Ultraviolet Light-Emitting Diodes

The effect of ZnO nanostructures on the light output power of 375 nm near-ultraviolet light-emitting diodes (NUV-LEDs) was investigated by comparing one-dimensional (1D) nanorods (NR-ZnO) with two-dimensional (2D) nanosheets (NS-ZnO). ZnO nanostructures were grown on a planar indium tin oxide (ITO) by solution based method at low temperature of 90°C without degradation of the forward voltage. At an injection current of 100 mA, the light output efficiency of NUV-LED with NR-ZnO was enhanced by around 30% compared to the conventional NUV-LEDs without ZnO nanostructures. This improvement is due to the formation of a surface texturing, resulting in a larger escape cone and a multiple scattering for the photons in the NUV-LED, whereas the light output efficiency of NUV-LED with NS-ZnO was lower than that of the conventional NUV-LEDs due to the internal reflection and light absorption in the defective sites of NS-ZnO

Ifosfamide-induced Fanconi syndrome with diabetes insipidus

Ifosfamide-induced Fanconi syndrome is a rare complication that typically occurs in young patients due to a cumulative dose of ifosfamide > 40-60 g/

Prevalence and prognostic implications of psychological distress in patients with gastric cancer

Abstract Background The aim of this study was to investigate the prevalence and prognostic significance of psychological distress in gastric cancer patients. Methods The study population included 229 gastric cancer patients visiting Yonsei Cancer Center between November 2009 and March 2011. The distress was measured by available tools including the Modified Distress Thermometer (MDT), Hospital Anxiety and Depression Scale (HADS), and Center for Epidemiologic Studies–Depression Scale (CES-D). Patients with psychological distress were defined as those who scored above the cut-off values in both the MDT and either one of the HADS or CES-D. Results The median age of patients was 56 (range, 20 to 86) and 97 (42.4%) patients were with stage IV disease status at enrollment. The overall prevalence of psychological distress was 33.6% (95% CI: 27.5–39.8%) in 229 gastric cancer patients. In multiple logistic regression analysis, lower education level (odds ratio [OR] 2.39; 95% confidence interval [CI] 1.11–5.17, P = 0.026) and higher disease stage (OR 2.72; 95% CI 1.47–5.03, P = 0.001) were associated with psychological distress. In stage I-III disease, patients with psychological distress had worse disease-free survival (DFS) (5-year DFS rate: 60% vs 76%, P = 0.49) compared with those without psychological distress. In stage IV disease (n = 97), patients with psychological distress showed poorer overall survival than those without psychological distress (median OS (Overall Survival): 12.2 vs. 13.8 months, P = 0.019). Conclusion Psychological distress is common in patients with all stages of gastric cancer and is associated with worse outcomes

Air-ring microstructure arrays for enhanced light extraction from a face-up light-emitting diode

In this Letter, a light-emitting diode (LED) with prism-shaped-air-ring microstructures (PSAMs) formed on flat sapphire substrate is demonstrated as an alternative design to face-up LEDs on patterned sapphire substrate (PSS) for enhanced light extraction efficiency. In this LED design, the emitted photons can be deflected to the top of the chip for its effective extraction, contrary to the PSS-LED wherein photons are guided to sapphire and get absorbed by packaging materials. The PSAM-LED showed an enhancement in the radiometric power as high as 10%with a low far-field angle of 129° over that of a PSS-LED under an injection current of 20 mA.1221sciescopu

Fabrication and Characteristics of GaN-Based Light-Emitting Diodes with a Reduced Graphene Oxide Current-Spreading Layer

A reduced graphene oxide (GO) layer was produced on undoped and n-type GaN, and its effect on the current- and heat-spreading properties of GaN-based light-emitting diodes (LEDs) was studied. The reduced GO inserted between metal electrode and GaN semiconductor acted as a conducting layer and enhanced lateral current flow in the device. Especially, introduction of the reduced GO layer on the n-type GaN improved the electrical performance of the device, relative to that of conventional LEDs, due to a decrease in the series resistance of the device. The enhanced current-spreading was further of benefit, giving the device a higher light output power and a lower junction temperature at high injection currents. These results therefore indicate that reduced GO can be a suitable current and heat-spreading layer for GaN-based LEDs