69 research outputs found
Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling
A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems
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Therapeutic hypogonadism induced by a delayed-release preparation of microcapsules of D-Trp-6-luteinizing hormone-releasing hormone: a preliminary study in eight women with endometriosis.
Eight menstrually cycling women with proven endometriosis were treated with a delayed-release preparation of the superactive agonist D-Trp-6-LH-RH in biodegradable microcapsules, administered intramuscularly at intervals of 16 to 36 days for a period of 3 to 5 months. After the first injection which caused a transient stimulatory response, a sustained hypogonadal state, characterized by an estradiol (E2) level less than 50 pg/mL, was induced in all patients by day +14.7 (range 7.19). Subsequent injections caused no more stimulation, but a continuous decrease in E2 levels was observed. In all patients, E2 levels fell to zero after the second or third injection. Gonadotropins remained in the normal range throughout the course of treatment. Hot flashes and severe dyspareunia (related to vaginal dryness) were the main side effects. Resumption of normal pituitary-ovarian activity was documented in all patients after the last injection; the end of the hypogonadal state, ovulation and menses, occurred on days 41 (range 32-59), 58 (range 51-64) and 70 (range 65-76), respectively. All patients showed a clinical improvement. Our results demonstrate that a long-lasting, reversible hypogonadism can be induced in cyclic women by intramuscular injections of D-Trp-6-LH-RH microcapsules at monthly intervals. This simple and convenient treatment should be useful in treating endometriosis and other conditions
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