Physical and optical properties of nanocrystalline calcium ferrite synthesized by the polymerized complex method.

Nanocrystalline CaFe2O4 oxide semiconductor with spinel structure was synthesized by polymerized complex (PC) method and investigated for its physical and optical properties. The crystallization of CaFe2O4 made by PC method was found to occur in the temperature range of 700-1100 degrees C. The observation of highly pure phase and such lower crystallization tempearture in CaFe2O4 made by PC method, is in total contrast to that observed in CaFe2O4 prepared by the conventional solid-state reaction (SSR) method. The activation energy required for the growth of nanocrystalline CaFe2O4 in PC sample was found to be 8.4 kJ/mol. The band gap of nanocrystalline CaFe2O4 determined by UV-DRS was 1.91 eV (647 nm). The photocatalytic activity of PC materials for iso-propyl alcohol photodegradation under visible light (> or =420 nm) was much higher than that of SSR materials.

Structures and related properties of AgX bearing 3,3'-thiobispyridine (X- = NO3-, BF4-, CLO4-, and PF6-.

Infinite molecular helices [Ag(3,3'-Py2S)]X (3,3'-Py2S = 3,3'-thiobispyridine; X- = BF4-, ClO4-, and PF6-) have been rationally constructed or induced. Crystallographic characterization (X- = BF-, monoclinic P2(1)/n, a = 8.946(3) A, b = 14.130(2) A, c = 10.124(2) A, beta = 107.83(2) degrees, V = 1218.3(5) A3, Z = 4, R = 0.0351; X- = ClO4-, monoclinic P2(1)/n, a = 8.884(1) A, b = 14.305(3) A, c = 10.110(1) A, beta = 106.78(1) degrees, V = 1230.1(3) A3, Z = 4, R = 0.0417; X- = PF6-, monoclinic P2(1)/c, a = 10.959(2) A, b = 9.808(2) A, c = 14.065(3) A, beta = 112.03(2) degrees, V = 1401.4(5) A3, Z = 4, R = 0.0442) reveals that the skeletal structure is an oblong cylindrical cationic helix consisting of alternating Ag(I) and 3,3'-Py2S species and that its counteranions are pinched in two columns inside each helix. The formation of the helical coordination polymer appears to be primarily associated with a suitable combination of the skewed conformer of 3,3'-Py2S and the potential linear geometry of the N-Ag(I)-N bond. However, the framework of the nitrate analogue [Ag(3,3'-Py2S)NO3] (monoclinic P2(1)/c, a = 8.177(2) A, b = 10.291(1) A, c = 14.771(2) A, beta = 102.19(1) degrees, V = 1214.9(4) A3, Z = 4, R = 0.0300) is a two-dimensional network consisting of an 18-membered ring unit, where each 3,3'-Py2S acts as a N,N',S- tridentate ligand connecting three tetrahedral silver(I) ions with the monodentate nitrate weakly bonded to the silver (Ag.O = 2.65(1) A) rather than acting as a counteranion. The anion exchange of [Ag(3,3'-Py2S)NO3] with BF4-, ClO4-, or PF6- has been accomplished in aqueous media. The two-dimensional networks are easily converted into the helices via the anion exchange, but the reverse anion exchange proceeds slightly. Thermal analyses indicate a relationship between the thermal stabilities and the structural properties.

Prevention of hyaline membrane disease with plasminogen. A cooperative study.

In a double-blind, randomized study, 500 premature infants were treated with plasminogen or placebo intravenously within 60 minutes of birth. There was a substantial decrease in severe clinical respiratory distress, death caused by hyaline membrane disease, and total mortality in the plasminogen-treated infants as compared to the controls.

Effect of various estrogen treatment schedules on antithrombin III levels.

Antithrombin III levels were determined in 18 normal indiviuals of both sexes, 24 pregnant women (at term), 20 patients treated with oral contraceptives and 21 postmenopausal patients treated with Premarin. There was no sex difference in antithrombin III levels in the untreated control group. Pregnant women at term had the lowest levels of antithrombin III. The second lowest values were exhibited by women on oral contraceptives. Both of these groups differed significantly (p less than 0.05) from the controls. Premarin treated postmenopausal women had somewhat lower levels of antithrombin III than controls but these were statistically not significant.

PIP: Antithrombin 3 levels were determined in 18 normal men and women (co ntrols), at term in 24 pregnant women, 20 women taking combined oral contraceptives (OCs), and 21 postmenopausal women on Premarin therapy. There were no differences in antithrombin 3 levels between men and women controls. Antithrombin 3 levels were lowest in pregnant women at term, and women taking OCs had the 2nd lowest levels. Both of these groups had significantly (p less than .05) lower levels of antithrombin 3 than controls. Antithrombin 3 levels were also depressed in the Premarin group, but were not markedly different from controls.

Studies on the prevention of respiratory distress syndrome of infants due to hyaline membrane disease with plasminogen.

Hyaline membrane disease (HMD) is leading single cause of death of newborn, premature infants. The "hyaline membranes" consist chiefly of fibrin. The clinical manifestation of HMD is the respiratory distress syndrome (RDS). Infants with RDS were treated with urokinase-activated human plasmin in a previous clinical trial. Survival rate was increased in the plasmin treated group as compared to the placebo recipients. However, cost and difficulty in the preparation of the enzyme made this treatment impractical. We, as well as others, have shown the premature infants lack serum plasminogen; thus they are unable to develop effective fibrinolysis and are defenseless against pulmonary fibrin deposition. Therefore, plamsinogen was tested as a possible preventive agent in RDS due to HMD. In a double blind, randomized study, infants between 1 and 2.5 kg birth weight received plasminogen or placebo shortly after birth, and were then followed for development of RDS. After 100 infants were entered into the study, the code was broken and results were evaluated to assure safety of the procedure. Among the 100 infants, 51 received placebo, 49 received plasminogen. Among the infants who received placebo, seven developed mild, and ten developed severe respiratory distress; of these ten, five died with histopathologically documented HMD. Two infants died from causes other than HMD. Among the 49 infants treated with plasminogen, 13 developed mild and three developed severe respiratory distress. There was no death due to HMD. Two deaths were due to other causes. Factors placing the infant at risk from HMD (degree of prematurity, sex, cesarean section, bleeding episodes during pregnancy, maternal diabetes) were found to be evenly distributed between control and treated groups. Since completing the first phase of the study, data of an additional 277 infants has become available. Although the code was not broken in this series, a preliminary look at mortality data in comparison with mortality data of the first series of 100 (in which the code was broken) suggests that preventive activity of plasminogen has been maintained in the second phase of the study.