The Influence of the Synthesis Method on the Characteristics of BaTiO3.

In this work, barium titanate powders were produced by sol-gel and sol-precipitation methods from metal alkoxides. In the sol-gel method, tetraisopropyl orthotitanate was mixed with 2-propanol, acetic acid and barium acetate, and the gel samples obtained were calcined at 600 °C, 800 °C and 1000 °C. Through the sol-precipitation method, tetraisopropyl orthotitanate was mixed with acetic acid and deionized water and precipitated by the addition of a concentrated solution of KOH. The products were calcined at various temperatures, and the microstructural and dielectric properties of the BaTiO3 prepared for the two processes were analyzed and compared. The results of these analyses allowed us to observe an increase in the tetragonal phase and the dielectric constant (15-50 at 20 kHz) with increasing temperatures in the samples produced by the sol-gel method, while the sample obtained by sol precipitation was cubic. The presence of BaCO3 is more evident in the sample produced by sol-precipitation, and the band gap of the products obtained did not show significant variation, changing the synthesis method (3.363-3.594 eV).

Multicenter, double-blind, comparative clinical study on the efficacy and acceptability of a monthly injectable contraceptive combination of 150 mg dihydroxyprogesterone acetophenide and 10 mg estradiol enanthate compared to a monthly injectable contraceptive combination of 90 mg dihydroxyprogesterone acetophenide and 6 mg estradiol enanthate.

Healthy, regularly menstruating women, aged 14-38 years, were enrolled in a comparative, double-blind, phase III, clinical trial to evaluate the contraceptive efficacy and acceptability of a combination of 90 mg dihydroxyprogesterone acetophenide with 6 mg estradiol enanthate compared to the commercially available contraceptive combination of 150 mg dihydroxyprogesterone acetophenide with 10 mg estradiol enanthate. Subjects received the contraceptive combination intramuscularly, between the 7th and 10th day of each menstrual cycle, during 12 consecutive menstrual cycles. Approximately 60% of the subjects in both groups completed the study. Principal reasons for discontinuation were personal, nonmedical reasons. Principal medical reasons for discontinuation were menstrual-related, irregular bleeding being the most frequent. Differences in menstrual patterns between the two groups did not lead to differences in discontinuation rates. Three contraceptive failures occurred during the trial, one in Group A (90/6 mg) and two in Group B (150/10 mg), indicating that the lower dose formulation is at least as efficient as the higher dose.

UK-74,505, a novel and selective PAF antagonist, exhibits potent and long lasting activity in vivo.

UK-74,505, a potent and selective PAF antagonist in vitro, has been shown to be extremely active given orally or intravenously to various species. In anaesthetised guinea pigs UK-74,505 at 30 & 100 micrograms/kg i.v. inhibited bronchoconstrictor responses to aerosolised PAF without affecting blood pressure or heart rate. The increased cutaneous vascular permeability to intradermal PAF in rats was inhibited by UK-74,505 with an ED50 of 280 +/- 5 micrograms/kg p.o. In conscious dogs, complete inhibition of PAF-induced whole blood aggregation ex-vivo occurred for at least 14 hours after an oral dose of 75 micrograms/kg. It is concluded that UK-74,505 is an effective, orally active PAF antagonist of long duration with the potential for once daily dosing.