We investigated the performance degradations mechanisms in n-channel perfluoropentacene thin-film transistors (PF-pentacene TFTs) exposed to dry O2. We found that the PF-pentacene TFTs are significantly degraded when they are operated in dry O2 rather than when just exposed to dry O2. Furthermore, the performance degradation resulting from exposure to dry O2 is caused by the mobility decrease, while that with the TFT operation in dry O2 is caused by the threshold voltage (Vth) increase as well as the mobility decrease. The present results indicate that an interaction between neutral PF-pentacene and O2 molecules induces a slight mobility decrease, while that between n-doped PF-pentacene and O2 molecules predominantly brings about a significant Vth increase.

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The mechanism of the photoinduced threshold voltage shift (ÁV T ) has been studied. We present clear evidence for electron trapping in the pentacene/SiO 2 interface region, which plays a significant role in device instability. A model of ÁV T and hysteresis due to the electron trapping in the pentacene/SiO 2 interface region is proposed on the basis of the experimental results of bias stressing under light. The deeper states in the pentacene forbidden gap are involved in the electron trapping by increasing the reverse bias under the irradiated condition. This results in the further positive shift of V T . In addition, it has been found that the trapped electron lifetime is well described by two time constants, which are thought to be associated with different trapping energy levels in the forbidden gap states of pentacene.

Many observational studies showed hogh-density lipoprotein cholesterol (HDL-C) is a strong inverse predictor of cardiovascular (CV) outcome. However, recent large clinical trials evaluating therapies to raise HDL-C level in those already on statin therapy have been discouraging. This complexity is not well-known.A total of 28,357 acute myocardial infarction (AMI) patients were enrolled in the Korea Acute Myocardial Infarction Registry (KAMIR), which was a prospective, multicenter, nationwide, web-based database of AMI in Korea. From this registry, we evaluated 3574 patients with AMI who have follow-up HDL-C level to investigate its association with clinical outcomes. The primary endpoint was the relationship between follow-up change in HDL-C and a 12-month composite of major adverse cardiac events (MACEs).Patients with initial HDL-C ≥ 40 mg/dL showed significantly lower rates of 12-month MACEs, especially cardiac and all-cause mortalities (P < 0.001). When patients were stratified into 4 groups according to the change of HDL-C, patients with decreasing HDL-C showed significantly higher rates of 12-month MACEs as comparable with patients with increasing HLD-C. A multivariate analysis indicated that HDL-C level was a significant predictor of CV events (hazard ratio, 1.38; 95% confidence interval, 1.12–1.71) after correcting for confounding variables.The follow-up change in HDL-C level was significantly related with CV outcomes in patients with AMI.