Detailed Reaction Mechanisms for the Oxidative Coupling of Methane over La2O3/CeO2 Nanofiber Fabric Catalysts
CHEMCATCHEM
Authors: Karakaya, Canan; Zhu, Huayang; Zohour, Bahman; Senkan, Selim; Kee, Robert J.
Abstract
We develop and validate detailed reaction mechanisms to represent the oxidative coupling of methane (OCM) over a La2O3/CeO2 nanofabric catalyst. The reaction mechanism includes 39 reversible gas-phase reactions and 52 irreversible surface reactions between 22 gas-phase species and 11 surface species. We use a model-based interpretation of spatially resolved concentration and temperature profiles measured by using a laboratory-scale packed-bed reactor. The reaction mechanisms are validated for inlet feed compositions in the range of 7 <= CH4/O-2 <= 11. The results are supported by a reaction pathway analysis that provides insight into the relative contributions of the gas-phase and surface reactions to form the desired C2+ and the undesired COx products. The results provide new quantitative insights into the complex nature of the OCM chemistry, which can assist practical process and reactor development.
Variations in hospitalization and emergency department/observation stays using the oncology care model methodology in Medicare data
CURRENT MEDICAL RESEARCH AND OPINION
Authors: Li, Shuling; Peng, Yi; Liu, Jiannong; Li, Suying; Raskin, Leon; Kelsh, Michael A.; Zaha, Rebecca; Gawade, Prasad L.; Henry, David; Lyman, Gary H.
Abstract
Objective To assess variations in hospitalizations, emergency department/observational (ED/OB) stays not resulting in hospitalization, reasons for hospitalization, and hospitalization discharge destinations after chemotherapy, information not provided as part of Oncology Care Model (OCM) baseline data. Methods OCM methodology was applied to the Medicare 20% sample data to identify 6-month patient episodes triggered by chemotherapy in 2012-2015. Proportions of episodes with hospitalization or ED/OB stays, reasons for hospitalization, and discharge destinations were summarized. Results Of 485,186 6-month episodes for 255,229 patients in 13,823 practices, 25% of episodes led to >= 1 hospitalization (from 14% in breast cancer to 56% in acute leukemia), and 23% to ED/OB stays (from 18% in breast cancer to 36% in liver cancer). In 2995 practices with >= 20 total episodes, practice-level proportions of episodes with hospitalization ranged from 14% to 31% (20th-80th percentile) and with ED/OB stays from 17% to 29%. For all cancers combined, the most frequent reasons for hospitalization were infection (13%), anemia (7%), dehydration (5%), and congestive heart failure (3%); the most common discharge destinations were home (71%) followed by a skilled nursing facility (13%), death (6%), and hospice (5%). Reasons for hospitalization and discharge destinations varied by cancer type; acute leukemia episodes led to the highest rates of infection and anemia, and central nervous system tumor episodes to the highest proportions of death or hospice discharge. Conclusion The variations in frequency of and reasons for hospitalization, ED/OB stays, and hospitalization discharge destinations across cancer types should be considered when evaluating OCM practice performance.