Untersuchung von Hyperfeinstrukturwechselwirkungen im 1274 keV-Niveau des204Pbm durch γγ-Winkelkorrelationsmessungen

The technique of differential γγ-angular correlation measurements has been applied to an investigation of the hyperfine interactions in the 1274 keV level of²⁰⁴Pb^m. Using liquid sources we derived from the interaction with an external magnetic field of 35,2 kgauss for the g-factor g=+0.055±0.003 in agreement with earlier measurements. The investigation of the quadrupole interaction with the statistically oriented electric field gradient of²⁰⁴Pb^m embedded in the lattice of metallic Thallium gave for the electric interaction frequency in the definition ofSteffen andFrauenfelder ω₀₁=(2.23±0.15) MHz. We observed an additional frequency of ω₀₂=(6.91±0.15) MHz. This second frequency is probably caused by crystal imperfections. It vanished when the metal sources were annealed after the cyclotron irradiation. Finally we investigated the perturbation of the γγ-angular correlation of the 912– 375 keV cascade by a combined interaction of the dipole moment of the intermediate 1274 keV state with an external magnetic field and its quadrupole moment with an statistically oriented static electric field gradient. We found good agreement with the theory ofAlder et al. 2.     

High spin states in the doubly-closed shell nucleus146Gd

High spin states of¹⁴⁶Gd, populated in heavyion induced reactions, have been investigated by means of in-beamγ-ray spectroscopy using the Compton-suppressed germanium detector arrays OSIRIS and ESSA30. 35 new levels and 47 new transitions could be placed in the level scheme. In addition to the extension to very high spins, a new cascade has been observed at intermediate spins.     

Microwave absorption studies of MgB2 superconductor

Microwave absorption studies have been carried out on MgB₂ superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for polycrystalline (grain size ∼ 10 μm) samples suggested the absence of weak-link character. The field dependent direct microwave absorption has been found to obey a ✓H dependence with two different slopes, which indicated a transition from strongly pinned lattice to flux flow regime.     

Search for superdeformation in180Os

Two-dimensional γ-ray energy correlations have been measured at high spins in¹⁸⁰0s with the TESSA2 spectrometer. The E_γ ? E_γcorrelation matrix displays ridges characteristic of rotational bands with different energy separations of 96± and 72± keV for the energy regions of 660 to 840 keV and 975 to 1170 keV, respectively. The separation of these ridges remains constant in both energy regions. The dynamical moments of inertia are θ⁽²⁾ =83±3 and 111±5 ?²/MeV, respectively. The latter value suggests superdeformation in¹⁸⁰0s with an axis ratio c/a=1.76 (β₂ ?0.64) at high spins.     

Excited superdeformed band in146Gd

A non-yrast superdeformed band has been found in¹⁴⁶Gd using the¹¹⁰Pd(⁴⁰Ar, 4n)¹⁴⁶Gd reaction. The nuclear assignment was made from the analysis of an experiment using a backed target. This band and the previously identified yrast SD band are probably not signature partners.     

Spectroscopy of195Hg and196Hg

High-spin states in the oblate-deformed nuclei¹⁹⁵Hg and¹⁹⁶Hg were populated in the¹⁹⁸Pt(α, xn) reaction and investigated by in-beamγ-ray spectroscopy using six Compton-suppressed Ge detectors. The level schemes of both nuclei are extended considerably. The level structure is interpreted within the framework of the cranked shell model. Good agreement is obtained between model predictions and experimental results.     

Determination of CYP activity in precision-cut liver slices: whether to use intact slices or slice homogenate

Despite CYP induction in vitro in precision-cut liver slices (LS) is well documented, there are no standardised assays for determining CYP activity as a major end-point. In this paper, short-term assays with intact and homogenised LS from male and female rats were directly compared. We obtained similar results for 7-ethoxycoumarine O-deethylation (ECOD) with LS from both sexes: higher basal activities were measured in LS homogenate, whereas slightly stronger induction by BNF was found with intact LS. CYP3A-dependent basal and dexamethasone (Dex)-induced 2β-, 15β- and 6β-testosterone hydroxylation (TH) rates were higher in both intact and homogenised LS from male compared to female rats. CYP3A induction in vitro could likewise be detected in intact and homogenised LS preferentially by determining 2β- and 15β-TH, with higher induction factors observed in LS from females. 6β-TH seems to be less inducible in intact LS of males. In vivo pretreatment of liver donors with BNF and Dex did not substantially disturb the subsequent in vitro induction of ECOD and TH, respectively.     

The FT-IR study of the brain tissue of Labeo rohita due to arsenic intoxication

The brain is believed to be particularly vulnerable to arsenic due to its high oxygen consumption rate and high level of polyunsaturated fatty acids and relatively high rate of oxygen free radical generate without commensurable level of arsenic. Hence, in the present work an attempt is made to study the changes in the biochemical contents in the brain tissues of edible fish Labeo rohita due to arsenic intoxication using Fourier Transform Infrared (FT-IR) spectroscopy. FT-IR spectra reveal significant differences in absorbance intensities between the control and arsenic intoxicated brain tissues, reflecting an alteration on the major biochemical constituents, such as lipids, proteins and nucleic acids of the brain tissues of L. rohita due to arsenic intoxication. Further, the administration of antidote DMSA improves the protein and lipid contents significantly in the brain tissues when compared to arsenic intoxicated tissues. The decrease in α-helix structure due to arsenic intoxication might be responsible for the increase in β-sheet secondary structures, which is consistent with the mechanism of β-sheet formation.