| 1. |
- Edelson, R. A., et al.
(författare)
-
Multiwavelength observations of short-timescale variability in NGC 4151. IV. Analysis of multiwavelength continuum variability
- 1996
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 470:1, s. 364-377377
-
Tidskriftsartikel (refereegranskat)abstract
- For pt.III see ibid., vol.470, no.1, p.349-63 (1996). Combines data from the three preceding papers in order to analyze the multi wave-band variability and spectral energy distribution of the Seyfert 1 galaxy NGC 4151 during the 1993 December monitoring campaign. The source, which was near its peak historical brightness, showed strong, correlated variability at X-ray, ultraviolet, and optical wavelengths. The strongest variations were seen in medium-energy (~1.5 keV) X-rays, with a normalized variability amplitude (NVA) of 24%. Weaker (NVA=6%) variations (uncorrelated with those at lower energies) were seen at soft gamma-ray energies of ~100 keV. No significant variability was seen in softer (0.1-1 keV) X-ray bands. In the ultraviolet/optical regime, the NVA decreased from 9% to 1% as the wavelength increased from 1275 to 6900 Aring. These data do not probe extreme ultraviolet (1200 Aring to 0.1 keV) or hard X-ray (250 keV) variability. The phase differences between variations in different bands were consistent with zero lag, with upper limits of lsim0.15 day between 1275 Aring and the other ultraviolet bands, lsim0.3 day between 1275 Aring and 1.5 keV, and lsim1 day between 1275 and 5125 Aring. These tight limits represent more than an order of magnitude improvement over those determined in previous multi-wave-band AGN monitoring campaigns. The ultraviolet fluctuation power spectra showed no evidence for periodicity, but were instead well fitted with a very steep, red power law (ales-2.5)
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Sundqvist, Bertil, et al.
(författare)
-
Physical properties of pressure polymerized C60
- 1996
-
Ingår i: Proceedings of the Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials. - Pennington, NJ : Electrochemical Society, Incorporated. - 1566771625 ; , s. 1014-1028
-
Konferensbidrag (refereegranskat)
|
|
| 5. |
|
|
| 6. |
- Eliasson, Lena, et al.
(författare)
-
PKC-dependent stimulation of exocytosis by sulfonylureas in pancreatic beta cells
- 1996
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 271:5250, s. 813-815
-
Tidskriftsartikel (refereegranskat)abstract
- Hypoglycemic sulfonylureas represent a group of clinically useful antidiabetic compounds that stimulate insulin secretion from pancreatic beta cells. The molecular mechanisms involved are not fully understood but are believed to involve inhibition of potassium channels sensitive to adenosine triphosphate (KATP channels) in the beta cell membrane, causing membrane depolarization, calcium influx, and activation of the secretory machinery. In addition to these effects, sulfonylureas also promoted exocytosis by direct interaction with the secretory machinery not involving closure of the plasma membrane KATP channels. This effect was dependent on protein kinase C (PKC) and was observed at therapeutic concentrations of sulfonylureas, which suggests that it contributes to their hypoglycemic action in diabetics.
|
|
| 7. |
- Ivanov, Alexander V., et al.
(författare)
-
Clathrate Formation of Bis(diethyldithiocarbamato)pyridinezinc(II) and Bis(diethyldithiocarbamato)pyridinecopper(II) with Benzene by EPR, High-Resolution Solid-State 13C and 15N NMR, and X-ray Crystallography
- 1998
-
Ingår i: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 43:9, s. 1368-1376
-
Tidskriftsartikel (refereegranskat)abstract
- The structures of the clathrates of bis(diethyldithiocarbamato)pyridinezinc(H) and-copper(II) with benzene were studied by EPR, high-resolution solid-state 13C and 15N NMR, and X-ray crystallography. The geometry of the coordination polyhedra in the clathrates M(EDtc)2· Py · C6H6is close to trigonal-bipyramidal. Two short M-S bonds and the M-N bond form the equatorial plane, and two long M-S bonds point toward the axial positions. For the magnetically diluted copper(II) clathrate, the hyperfine structure can be observed at low temperatures due to the nitrogen atom of pyridine, which is associated with the contribution of the dz2orbital to the ground-state wave function of the unpaired electron. The 13C and 15N NMR signals were assigned.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
