Herein, density functional theory (DFT) computations were performed to investigate the discrete dimer of a mono-substituted anthracene derivative (2-TA-AN), which exhibited highly efficient pure excimer fluorescence in its crystal form. As a more practical model, its geometry, potential energy curve and excited state property were systematically calculated to better understand the excimer formation process and photophysical properties. The compressed excimer geometry is responsible for the highly efficient excimer emission, arising from the enhanced rigidity that greatly suppresses its non-radiative vibrations. Potential energy curves along three directions reveal the non-uniqueness of excimer formation along the long axis of anthracene, which is in a good agreement with the experimental findings. Upon decreasing the displacement, the intermonomer charge-transfer (CT) component gradually increased towards an approximately equivalent hybridization with the locally-emissive (LE) state of the monomer during the formation of the excimer. The excimer emission wavelength versus intermonomer CT content shows a similar trend along the three directions, revealing a turning point related to the essential transition of the excited state properties from the LE of the monomer to the HLCT of the excimer. The present results will contribute to the better understanding of the structure-property relationships in excimer formation and photophysical properties.

Excited state properties play a key role in the photoluminescence (PL) and electroluminescence (EL) performance of organic light-emitting diode (OLED) materials. The solvatochromic effects were observed in a series of triphenylamine (TPA)-phenanthroimidazole (PI) derivatives with the increase of solvent polarity, accompanied by the transformation of an excited state character from the locally-excited (LE) state to the charge-transfer (CT) state in the emission spectra. The excited state properties were systematically investigated in these donor-acceptor systems using time-dependent density functional theory (TD-DFT). The hybridization and de-hybridization processes between LE and CT states were resolved with an increasing number of phenyls along horizontal and vertical directions, respectively. We provide a novel insight into the fine modulation of the excited-state characters and compositions in the donor-acceptor system for the new-generation, low-cost and high-efficiency fluorescent OLED materials.

BackgroundA hip fracture is a debilitating condition that consumes significant resources in the United States. Surgical treatment of hip fractures can achieve better survival and functional outcomes than nonoperative treatment, but less is known about its economic benefits.Questions/purposesWe asked: (1) Are the societal benefits of hip fracture surgery enough to offset the direct medical costs? (2) Nationally, what are the total lifetime benefits of hip fracture surgery for a cohort of patients and to whom do these benefits accrue?MethodsWe estimated the effects of surgical treatment for displaced hip fractures through a Markov cohort analysis of patients 65 years and older. Assumptions were obtained from a systematic literature review, analysis of Medicare claims data, and clinical experts. We conducted a series sensitivity analyses to assess the effect of uncertainty in model parameters on our estimates. We compared costs for medical care, home modification, and long-term nursing home use for surgical and nonoperative treatment of hip fractures to estimate total societal savings.ResultsEstimated average lifetime societal benefits per patient exceeded the direct medical costs of hip fracture surgery by USD 65,000 to USD 68,000 for displaced hip fractures. With the exception of the assumption of nursing home use, the sensitivity analyses show that surgery produces positive net societal savings with significant deviations of 50% from the base model assumptions. For an 80-year-old patient, the breakeven point for the assumption on the percent of patients with hip fractures who would require long-term nursing home use with nonoperative treatment is 37% to 39%, compared with 24% for surgical patients. Nationally, we estimate that hip fracture surgery for the cohort of patients in 2009 yields lifetime societal savings of USD 16 billion in our base model, with benefits and direct costs of USD 21 billion and USD 5 billion, respectively. For an 80-year-old, societal benefits ranged from USD 2 billion to USD 32 billion, using our range of estimates for nursing home use among nonoperatively treated patients who are immobile after the fracture.ConclusionsSurgical treatment of hip fractures produces societal savings. Although the magnitude of these savings depends on model assumptions, the finding of societal savings is robust to a range of parameter values.Level of EvidenceLevel III, economic and decision analyses. See the Instructions for Authors for a complete description of levels of evidence.Electronic supplementary materialThe online version of this article (doi:10.1007/s11999-014-3820-6) contains supplementary material, which is available to authorized users.

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The finite-element (FE) method is widely recognized as a powerful tool in modeling structural and geotechnical systems and simulating their response to static and dynamic loads. In addition, numerical optimization is commonly used in many engineering applications, such as structural reliability analysis, FE model updating, structural identification, and structural optimization. This paper focuses on the extension of Open System for Earthquake Engineering Simulation (OpenSees, an existing software framework for nonlinear FE analysis) using Sparse Nonlinear Optimization (SNOPT, a state-of-the-art numerical optimization software). The extended OpenSees-SNOPT framework is general and flexible and can be used to solve a wide range of FE-based optimization problems in structural and geotechnical engineering. It has several distinguishing features: (1) advanced capabilities in solving optimization problems involving complex structural/geotechnical engineering systems; (2) versatility in modeling a very wide range of structural and/or geotechnical systems; (3) computational efficiency; (4) flexibility to easily accommodate and benefit from new developments in FE structural modeling and analysis, computational optimization, and probabilistic modeling and analysis; and (5) capabilities of exploring new optimization-based problems and solution methods. The use of this coupled framework is illustrated through three representative application examples, i.e., a FE reliability analysis of a reinforced concrete frame, a FE structural optimization problem of an electrical transmission steel tower, and a FE model updating the problem of a geotechnical system. DOI: 10.1061/(ASCE)ST.1943-541X.0000511. (C) 2012 American Society of Civil Engineers.Pacific Earthquake Engineering Research (PEER) Center [00006493]; Longwell's Family Foundation; LSU Council on Research; Louisiana Board of Regents (LA BoR) through the Louisiana Board of Regents Research and Development [LESQSF(2010-13)-RD-A-01]; National Science Foundation [DMS-0915220]; Fundamental Research Funds for the Central Universities of China [2010111075

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We explore how and to what extent prescription drug insurance expansions affects incentives for pharmaceutical advertising. When insurance expansions make markets more profitable, firms respond by boosting advertising. Theory suggests this effect will be magnified in the least competitive drug classes, where firms internalize a larger share of the benefits from advertising. Empirically, we find that the implementation of Part D coincides with a 14% to 19% increase in total advertising expenditures. This effect is indeed concentrated in the least competitive drug classes. The additional advertising raised utilization among non-elderly patients outside the Part D program by about 3.6%. This is roughly half of the direct utilization effect of Part D on elderly beneficiaries. The results suggest the presence of considerable spillover effects from publicly subsidized prescription drug insurance on the utilization and welfare of consumers outside the program.