Cross-over from pyrene to acene optical and electronic properties: a theoretical investigation of a series of pyrene derivatives fused with N-, S, and O-containing heterocycles.

Pyrene and acene derivatives are an important source of materials for optoelectronic device applications both as emitters and organic semiconductors. The mobility of major charge carriers is correlated with the coupling constants of the respective major charge carrier as well as the relaxation energies. Herein, we have applied range-separated density functionals for the estimation of said values. A series of five alkylated derivatives of pyrene laterally extended by heteroaromatic or phenyl groups were explored and contrasted to nascent pyrene, alkylated pyrene and tetracene. The ground state geometries along with absorption properties and relaxation energies are presented as well as a discussion of the suitability of the material toward hole and electron transport materials.

Outcome analysis of brain-death referral to NOD-Lb: A retrospective chart review of a single hospital experience over 3 years.

BACKGROUND: Organ donation shortage and in particular organ procurement is an international concern as the gap between the number of donors and recipients is steadily growing. Organ procurement is a chain of steps with donor identification and referral (ID&R) as the very first link in this chain. Failure of this step hinders the progress in the organ transplantation program. OBJECTIVES: Our study was conducted to evaluate and highlight the gap between the national system and the practice at the identification and referral (ID&R) step of the organ procurement chain in a single tertiary-care academic health center in Beirut: the Lebanese American University Medical Center-Rizk Hospital (LAUMC-RH), and to appraise the literature for challenges at this step and for possible interventions for improvement based on the international experience. MATERIALS AND METHODS: This retrospective study was a descriptive case series of ICU and ED deceased patients at a single tertiary-care university hospital in Beirut. Patients' characteristics were collected from medical records for all patients who died between 2017 and 2019 while in the ICU or the ED and shared with the National Organization for Organ and Tissue Donation and Transplantation (NOD-Lb), for each subject separately, to decide on the donor status. All data collected from the patient cohort was analyzed using R version 3.6.1. Wilcoxon signed-rank test, chi-squared, and fisher-exact tests were used to compare differences in clinical characteristics in terms of donor status when appropriate. RESULTS: This study served as 3 years audit of a single hospital experience, and it demonstrates failure to make any referrals to NOD-Lb and zero actual organ and tissue donations over the study period. The review of 295 deceased subjects' charts demonstrates 295 missed alerts to NOD-Lb and the overall missing of 5 organ and tissue donors and 24 cornea donors assuming the organ procurement chain of steps will continue uninterrupted after ID&R. CONCLUSION: The data gathered suggests the presence of an inefficient identification and referral system that is translated into a complete failure of reporting to NOD-Lb from LAUMC-RH. A systematic evidence-based approach to evaluate for the most cost-effective intervention to increase identification and referral rates is needed with a serious effort to examine and account for any inefficient implantation.