Effect of Blending Ratio and Temperature on CO2 Solubility in Blended Aqueous Solution of Monoethanolamine and 2-Amino-2-methyl-propanol: Experimental and Modeling Study Using the Electrolyte Nonrandom Two-Liquid Model.

This paper reports the newly measured experimental data for CO2 solubility in a blended aqueous solution of monoethanolamine (MEA) and 2-amino-2-methyl-propanol (AMP) at different amine mixing ratios (MEA/AMP/H2O = 9:21:70, 15:15:70, and 21:9:70 wt %) and working temperatures (323.15, 373.15, and 383.15 K). The successive substitution method was used for calculating the mole fractions of all molecules (four molecules) and electrolytes (three cations and four anions) from the equilibrium along with the material and charge balance equations (11 equations). The electrolyte nonrandom two-liquid (e-NRTL) model was used to investigate nonideality in the liquid phase. Using the abovementioned thermodynamic models, the partial pressures of CO2 in the gas phase, mole fractions of all components in the liquid phase, pH variations, heats of absorption, and cyclic capacities of CO2 according to the absorption/desorption temperature and the blending ratio of MEA/AMP were estimated.

Health Care Utilization and Direct Costs in Mild, Moderate, and Severe Adult Asthma: A Descriptive Study Using the 2014 South Korean Health Insurance Database.

PURPOSE: Although asthma exacerbation comprises a large burden of the total asthma-related costs, few studies have examined the frequency and cost of acute exacerbation according to asthma severity. This study investigated asthma-related health care utilization and costs according to the severity of asthma. METHODS: We conducted a descriptive study using the national health insurance claims database between January 1 and December 31, 2014. We included adult patients with asthma (18 years of age and older) who had ≥2 claims with for an asthma diagnosis and were prescribed ≥1 asthma medications. They were classified into 3 asthma severity levels (level 1 = mild, level 2 = moderate, and level 3 = severe), based on individual medication prescriptions. Acute exacerbation was defined as having a corticosteroid burst, an emergency department visit, or hospitalization. Health care utilization, acute exacerbation, and direct costs associated with asthma were compared according to asthma severity levels. FINDINGS: Of the 36,687 adult asthma patients, level 1 had the largest proportion of patients (81.2%), followed by level 2 (18.2%), and level 3 (0.6%). The average number of asthma-related outpatient visits was 4.5 for level 1, 7.2 for level 2, and 11.9 for level 3 (P < 0.01). The estimated asthma-related direct cost per patient was $174 for level 1, $634 for level 2, and $1635 for level 3 (P < 0.01). The number of patients who experienced acute exacerbation increased as asthma severity increased: level 1, 22.6%; level 2, 26.0%; and level 3, 48.7% (P < 0.01). Direct costs associated with asthma exacerbation dramatically increased and accounted for 15.1% of the total cost in level 1 patients, 19.5% in level 2 patients, and 40.8% in level 3 patients (P < 0.01). IMPLICATIONS: The direct costs of acute exacerbation increased as asthma severity increased. In patients with severe asthma, acute exacerbation and the relative cost ratio in South Korea were higher than those in other countries. Proper management is required to avoid acute exacerbations and to reduce the burden of asthma, particularly in patients with severe asthma.