Exciton-relaxation dynamics in lead halides

We survey recent comprehensive studies of exciton relaxation in the crystals of lead halides. The luminescence and electron-spin-resonance studies have revealed that excitons in lead bromide spontaneously dissociate and both electrons and holes get self-trapped individually. Similar relaxation has been also clarified in lead chloride. The electron-hole separation is ascribed to repulsive correlation via acoustic phonons. Besides, on the basis of the temperature profiles of self-trapped states, we discuss the origin of luminescence components which are mainly induced under one-photon excitation into the exciton band in lead fluoride, lead chloride, and lead bromide.Comment: REVTeX, 5 pages, 5 figure

Effect of Hydrogen Peroxide and High Glucose on the Glucose Metabolism of Lymphoma-derived U937 Cells

Our study aimed to clarify specific oxidative stress and glucose metabolic disorders in hemodialysis patients, by examining hydrogen peroxide (H2O2) - and high glucose-induced oxidative stress, glucose transport and the failure of glycolysis. As an in vitro blood cell model of end-stage renal disease (ESRD) in patients with diabetes, human monocytic U937 cells of malignant lymphoma origin were exposed to high glucose (28.9mM) for 6 days, with 5mM H2O2 added on the last day. The generation of intracellular reactive oxygen species (ROS), glucose levels, lactate levels, AMP-activated protein kinase (AMPK) activity and Glut4 levels were examined. Exposure of U937 cells to H2O2 resulted in a significant increase in intracellular ROS generation and glucose levels. Under high glucose conditions, treatment with H2O2 significantly promoted these actions. In H2O2-induced U937 cells, AMPK activity and Glut4 levels were significantly increased, but lactate and pyruvate levels were significantly decreased. Thus, exposure of U937 cells to H2O2 and a high glucose load promoted an increase in intracellular ROS, and exposure to H2O2 induced increased glucose transport and high intracellular glucose due to reduced glycolytic metabolism. This suggests that reduced glycolytic metabolism might be induced in states of high oxidative stress in hemodialysis patients with diabetes