Improving efficiency roll-off in organic light emitting devices with a fluorescence-interlayer-phosphorescence emission architecture

Organic light emitting devices (OLEDs) with a fluorescence-interlayer- phosphorescence emission layer structure (FIP EML) has been proposed to solve the efficiency roll-off issue effectively. Efficient green OLED based on FIP EML exhibiting only 26% roll-off in the luminance efficiency, which is lower than the typical roll-off of 51% for conventional phosphorescent OLEDs with single EML operated at 5-150 mA/cm2 range, has been demonstrated. Such enhancement should be attributed to the improved carrier balance, the exciton redistribution in recombination zone, the suppression of nonradiative exciton quenching processes, and the elimination of energy transfer loss offered by the FIP EML structure. © 2009 American Institute of Physics.published_or_final_versio

Spherically shaped active transducer based on proton-irradiated vinylidene fluoride-trifluoroethylene 70/30 mol% copolymer

2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Pyroelectric properties of PZT/P(VDF-TrFE) 0-3 composites

Author name used in this publication: F. G. ShinRefereed conference paper2000-2001 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Characterization of proton irradiated copolymer thin films for microelectromechanical system applications

2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

A Step Toward Workplace Obesity Prevention: Evaluation of Weight Management Program for Hospital-based Health Care Providers

Background: Obesity is a worldwide problem. Healthy workplace and lifestyle are crucial in preventing obesity. A workplace weight management program could create a culture of health and facilitate weight control among health care providers. The present study aims to describe and evaluate the health outcomes of the interaction of professional practice and organizational infrastructure. Method: The hospital-based weight management program was an eight-week pilot randomized controlled study for obese health care providers. The primary outcomes were body weight and body mass index. The secondary outcomes included serum fasting glucose, fasting cholesterol, triglyceride, high- and low-density lipoprotein, body fat percentage, body mass, and quality of life. The RE-AIM framework was used to examine the intervention’s reach, effectiveness, adoption, implementation and maintenance at individual and organizational levels. Results: The program successfully attained the target population. Health care providers demonstrated short-term weight loss and decreased serum fasting cholesterol level after completing the program. The excellent retention rate (95%) of the study suggested that the participants were well-engaged in self-weight management. The program was implemented with adequate resource and support from the health organization. The organization may consider continuing the program in view of its long-term benefits to health care providers. Conclusion: Supportive organizational structure and culture enhanced professional practice and improved the health outcomes of the hospital-based weight management program participants

Discrete molecular dynamics can predict helical prestructured motifs in disordered proteins.

Intrinsically disordered proteins (IDPs) lack a stable tertiary structure, but their short binding regions termed Pre-Structured Motifs (PreSMo) can form transient secondary structure elements in solution. Although disordered proteins are crucial in many biological processes and designing strategies to modulate their function is highly important, both experimental and computational tools to describe their conformational ensembles and the initial steps of folding are sparse. Here we report that discrete molecular dynamics (DMD) simulations combined with replica exchange (RX) method efficiently samples the conformational space and detects regions populating alpha-helical conformational states in disordered protein regions. While the available computational methods predict secondary structural propensities in IDPs based on the observation of protein-protein interactions, our ab initio method rests on physical principles of protein folding and dynamics. We show that RX-DMD predicts alpha-PreSMos with high confidence confirmed by comparison to experimental NMR data. Moreover, the method also can dissect alpha-PreSMos in close vicinity to each other and indicate helix stability. Importantly, simulations with disordered regions forming helices in X-ray structures of complexes indicate that a preformed helix is frequently the binding element itself, while in other cases it may have a role in initiating the binding process. Our results indicate that RX-DMD provides a breakthrough in the structural and dynamical characterization of disordered proteins by generating the structural ensembles of IDPs even when experimental data are not available

TonEBP suppresses adipogenesis and insulin sensitivity by blocking epigenetic transition of PPAR gamma 2

TonEBP is a key transcription factor in cellular adaptation to hypertonic stress, and also in macrophage activation. Since TonEBP is involved in inflammatory diseases such as rheumatoid arthritis and atherosclerosis, we asked whether TonEBP played a role in adipogenesis and insulin resistance. Here we report that TonEBP suppresses adipogenesis and insulin signaling by inhibiting expression of the key transcription factor PPAR gamma 2. TonEBP binds to the PPAR gamma 2 promoter and blocks the epigenetic transition of the locus which is required for the activation of the promoter. When TonEBP expression is reduced, the epigenetic transition and PPAR gamma 2 expression are markedly increased leading to enhanced adipogenesis and insulin response while inflammation is reduced. Thus, TonEBP is an independent determinant of adipose insulin sensitivity and inflammation. TonEBP is an attractive therapeutic target for insulin resistance in lieu of PPAR gamma agonistsopen0

The Effect of a ΔK280 Mutation on the Unfolded State of a Microtubule-Binding Repeat in Tau

Tau is a natively unfolded protein that forms intracellular aggregates in the brains of patients with Alzheimer's disease. To decipher the mechanism underlying the formation of tau aggregates, we developed a novel approach for constructing models of natively unfolded proteins. The method, energy-minima mapping and weighting (EMW), samples local energy minima of subsequences within a natively unfolded protein and then constructs ensembles from these energetically favorable conformations that are consistent with a given set of experimental data. A unique feature of the method is that it does not strive to generate a single ensemble that represents the unfolded state. Instead we construct a number of candidate ensembles, each of which agrees with a given set of experimental constraints, and focus our analysis on local structural features that are present in all of the independently generated ensembles. Using EMW we generated ensembles that are consistent with chemical shift measurements obtained on tau constructs. Thirty models were constructed for the second microtubule binding repeat (MTBR2) in wild-type (WT) tau and a ΔK280 mutant, which is found in some forms of frontotemporal dementia. By focusing on structural features that are preserved across all ensembles, we find that the aggregation-initiating sequence, PHF6*, prefers an extended conformation in both the WT and ΔK280 sequences. In addition, we find that residue K280 can adopt a loop/turn conformation in WT MTBR2 and that deletion of this residue, which can adopt nonextended states, leads to an increase in locally extended conformations near the C-terminus of PHF6*. As an increased preference for extended states near the C-terminus of PHF6* may facilitate the propagation of β-structure downstream from PHF6*, these results explain how a deletion at position 280 can promote the formation of tau aggregates