Wet to Dry Controls Lanthanide Scandate Synthesis.

The choice of temperature and gas conditions used in a water pressure-controlled reactor is guided by density functional theory (DFT) to synthesize nearly phase-pure lanthanide scandate nanoparticles (LnScO3, Ln = La, Nd, Sm, Gd). In this synthetic method, low water-vapor partial pressures, well below water's gas liquidus, inhibit particle growth, while an excess of water vapor results in undesired rare-earth hydroxide and oxyhydroxide secondary phases. The optimal humidity for high-purity LnScO3 particle synthesis is shown to vary with the lanthanide; DFT is used to calculate the thermodynamics of secondary phase formation for each lanthanide tested such that the role of water vapor may be quantified and used to maintain phase purity (greater than 96 mol %) across the series. The combination of thermodynamic calculation and experimental confirmation with this pressure-controlled reactor provides an opportunity to explore analogous syntheses of other inorganic perovskite nanoparticles.

Decreased expression of pigment epithelium derived factor (PEDF), an inhibitor of angiogenesis, in placentas of unexplained stillbirths.

Normal placental vascular development depends upon the complex interactions between angiogenic inducers and inhibitors within the placenta. Alterations within the placental microenvironment can promote an imbalance in angiogenic mediators which may be associated with adverse perinatal outcomes. The purpose of this study was to investigate the placentas of infants with unexplained stillbirth as compared to live-born infants and to determine whether alterations in angiogenic inducer vascular endothelial growth factor (VEGF) or inhibitor pigment epithelium-derived factor (PEDF) are associated with altered angiogenesis, vascular remodeling and stillbirth. Placentas of 22 unexplained stillbirths and 44 age-matched live-born controls were scored for microvascular density (MVD), vasculopathy and microvascular permeability. A subset was scored for expression of angiogenic inducer VEGF and inhibitor pigment epithelium-derived factor. Stillborn placentas demonstrated higher MVD than controls (mean+SD: 116.6+/-46.3 v. 60.8+/-13.5, respectively, p<0.001). Vasculopathy was present in 10/22 (45%) stillbirths compared to 0/44 (0%) controls (p<0.001); increased vascular permeability was present in 15/22 (68%) cases and 5/44 (11%) controls (p<0.001). PEDF expression was significantly lower in stillborn placentas (1.7+/-0.3) than live-born controls (3.6+/-0.8, p<0.01) while VEGF expression was similar (3.3+/-0.7 v. 3.7+/-0.4, respectively, p>0.05). In conclusion, we found that unexplained stillbirth is associated with loss of angiogenic inhibitor PEDF, vasculopathy and heightened angiogenesis in the placenta.