No abstract

Photoemission, autoionization, and x-ray-absorption spectroscopy of ultrathin-film C60 on Au(110) Brühwiler, P.A.; Nilsson, A.; Mårtensson, N.; Rudolf, Petra

No abstract

The physical and electronic structure of the dispersed and (2ϫ2) phases of K/graphite have been characterized by valence and core-level photoemission. Charge transfer from K to graphite is found to occur at all coverages, and includes transfer of charge to the second graphite layer. A rigid band description is reasonably successful in describing important aspects of the data, and our results are consistent with a shift of approximately 0.4 eV in the surface graphite layer for both phases. The C 1s line shape and binding-energy shift as a function of charge transfer can be understood qualitatively by taking into account rigid band effects and the effects of a core hole on the density of states. For the ͑2ϫ2͒ phase the metallic overlayer contributes extrinsic satellites to the C 1s line shape. The K 3p spectrum is strongly affected by the overlayer phase, and in addition indicates very little variation in the substrate charge distribution as a function of coverage in the dispersed phase. The lack of an interface K 3p binding-energy shift for a K bilayer or multilayer is ascribed to a weak K-graphite bond for metallic overlayers. The results have implications for the interpretation of photoelectron spectra of alkali graphite intercalation compounds ͑GIC's͒. ͓S0163-1829͑99͒09111-0͔

Background-We have recently reported that hypercholesterolemia reduces aerobic exercise capacity in mice and that this is associated with a reduced endothelium-dependent vasodilator function, endothelium-derived nitric oxide (EDNO) production, and urinary nitrate excretion. These findings led us to test the hypothesis that EDNO production contributes significantly to limb blood flow during exercise and to determine whether loss of EDNO production is responsible for the decline in exercise capacity observed in hypercholesterolemia. Methods and Results-Twelve-week-old wild-type (E ϩ ; nϭ9) and apoE-deficient (E Ϫ ; nϭ9) C57BL/6J mice were treadmill-tested to measure indices defining exercise capacity on a metabolic chamber-enclosed treadmill capable of measuring oxygen uptake and carbon dioxide excretion. Urine was collected before and after treadmill exercise for determination of vascular NO production assessed by urinary nitrate excretion. The wild-type mice were then given nitro-L-arginine (E ϩ LNA) in the drinking water (6 mg/dL) for 4 days before undergoing a second treadmill testing and urinary nitrate measurement. An additional set of 12-week-old wild-type mice was divided into 2 groups: 1 receiving regular water (E ϩ ; nϭ8) and 1 administered LNA for 4 days (E ϩ LNA; nϭ8). These mice, along with an additional set of E Ϫ mice (nϭ8), underwent treadmill testing to determine maximal oxygen uptake (V O 2 max). The mice were then cannulated such that the tip of the tubing was positioned in the ascending aorta. Fluorescent microspheres (20 000) were infused into the carotid cannula while the mice were sedentary and again while approaching V O 2 max. When the mice were euthanized, the running muscles were collected and fluorescence intensity was measured to determine the peak-exercise redistribution of blood flow to the running muscles (expressed as percentage of total cardiac output, %COrm) during both states. Both E ϩ LNA and E Ϫ mice demonstrated a markedly reduced postexercise urinary nitrate excretion, aerobic capacity, and %COrm at V O 2 max compared with E ϩ . Conclusions-EDNO contributes significantly to limb blood flow during exercise. Conditions that reduce EDNO production disturb the hyperemic response to exercise, resulting in a reduced exercise capacity. (Circulation. 1998;98:369-374.)