Vocabulary and reading comprehension : instructional effects

Bibliography: leaves 32-34Supported by the National Institute of Educatio

Endothelial preconditioning by transient oxidative stress reduces inflammatory responses of cultured endothelial cells to TNF-α

Brief episodes of ischemia can render an organ resistant to subsequent severe ischemia. This ‘ischemic preconditioning’ is ascribed to various mechanisms, including oxidative stress. We investigated whether preconditioning exists on an endothelial level. Human umbilical vein endothelial cells (HUVECs) were transiently confronted with oxidative stress (1 mM H2O2, 5 min). Adhesion molecules ICAM-1 and E-selectin and release of cytokines IL-6 and IL-8 to subsequent stimulation with TNF-α (2.5 ng/ml, 4 h) were measured (flow cytometry and immunoassay), as were nuclear translocation of the transcription factor NFkB (Western blotting, confocal microscopy) and redox status of HUVECs (quantification of glutathione by HPLC). TNF-α elevated IL-6 in the cell supernatant from 8.8 ± 1 to 41 ± 3 pg/ml and IL-8 from 0.5 ± 0.03 to 3 ± 0.2 ng/ml. ICAM-1 was increased threefold and E-selectin rose eightfold. Oxidative stress (decrease of glutathione by 50%) reduced post-TNF-α levels of IL-6 to 14 ± 3 and IL-8 to 1 ± 0.2; the rise of ICAM-1 was completely blocked and E-selectin was only doubled. The anti-inflammatory effects of preconditioning via oxidative stress were paralleled by reduction of the translocation of NFkB on stimulation with TNF-α, and antagonized by the intracellular radical scavenger N-acetylcysteine. ‘Anti-inflammatory preconditioning’ of endothelial cells by oxidative stress may account for the inhibitory effects of preconditioning on leukocyte adhesion in vivo

Photonic Band Gaps in 3D Network Structures with Short-range Order

We present a systematic study of photonic band gaps (PBGs) in three-dimensional (3D) photonic amorphous structures (PAS) with short-range order. From calculations of the density of optical states (DOS) for PAS with different topologies, we find that tetrahedrally connected dielectric networks produce the largest isotropic PBGs. Local uniformity and tetrahedral order are essential to the formation of PBGs in PAS, in addition to short-range geometric order. This work demonstrates that it is possible to create broad, isotropic PBGs for vector light fields in 3D PAS without long-range order.Comment: 6 pages, 8 figure

Mixing-Demixing transition in 1D boson-fermion mixture at low fermion densities

We numerically investigated the mixing-demixing transition of the boson-fermion mixture on a 1D lattice at an incommensurate filling with the fermion density being kept below the boson density. The phase diagram we obtained suggested that the decrease of the number of the fermions drove the system into the demixing phase