Characterisation and molecular association of Nigerian and Sudanese Acacia gum exudates

The chemical and physicochemical characteristics of gum exudate samples harvested from mature trees of Acacia senegal at two new specific ecolocations in Nigeria, have been investigated together with gum samples harvested from A. senegal and A. seyal originating from Sudan. The monosaccharide sugar compositions for the A. senegal gum samples were found to be similar, but the protein contents for the Nigerian samples were significantly higher than recorded for the Sudanese sample. Gel Permeation Chromatography coupled to light scattering, refractive index and U.V. detectors, has shown the presence of arabinogalactan, arabinogalactan–protein and glycoprotein fractions within the A. senegal gums and has also shown the presence of an additional small proportion of very low molar mass proteinaceous material all the samples which has previously been ignored. The plot of radius of gyration, Rg, as a function of elution volume showed a discontinuity for one of the Nigerian samples and for the A. seyal gum sample at elution volumes corresponding to the AGP component suggesting a different molecular structure. Plots of Mw–v–Rg confirmed that the molecules had a compact structure. The hydrodynamic size of the molecules was followed using dynamic light scattering as a function of time and it was found that molecular association occurred in solution. The extent of association increased as the protein content in the sample increased and was inhibited in the presence of electrolyte, it was concluded that association was due to electrostatic interaction between the protein moieties and glucuronic acid groups on individual macromolecules

Hormonal profile and haematological parameters of male wistar albino rats treated with methanloic extract of Parthenium hysterophorus L.

Changes in hormonal and haematological level were assessed in male wistar albino rats treated with methanolic extract of Parthenium hysterophorus L. The result showed that methanolic extract treatment caused a significant (p < 0.01) reduction of 20 % and 40% in total RBC count (6.25 ± 0.025 to 5 ± 0.5 x 106/µL) and haemoglobin (17.1 ± 0.1892 to 10.2 ± 0.79 g / dL) respectively in treated rats over control. Unlike haematological parameters, hormonal profile showed a significant increase of 40% (p < 0.05), 200% (p < 0.01), 100% (p < 0.01) and 45.08% (p < 0.001) in follicle stimulating hormone, leutinizing hormone, prolactin and testosterone respectively. The reduction of blood parameters is due to less haemopoiesis or induction of anemia. The increase in hormone level may be a cause of prostate cancer in wistar albino rats

Generation of Bianchi type V cosmological models with varying Λ\Lambda-term

Bianchi type V perfect fluid cosmological models are investigated with cosmological term $\Lambda$ varying with time. Using a generation technique (Camci {\it et al.}, 2001), it is shown that the Einstein's field equations are solvable for any arbitrary cosmic scale function. Solutions for particular forms of cosmic scale functions are also obtained. The cosmological constant is found to be decreasing function of time, which is supported by results from recent type Ia supernovae observations. Some physical aspects of the models are also discussed.Comment: 16 pages, 3 figures, submitted to CJ

Excited superdeformed bands in Dy154 and cranked relativistic mean field interpretation

A Gammasphere experiment has been carried out using the Sn122(S36,4n) reaction to search for excited superdeformed (SD) structures in Dy154 to investigate the properties of neutron orbitals at superdeformation. Five new excited SD bands have been identified with intensities ranging from ~0.7% to ~0.03% relative to the Dy154 reaction channel. Bands SD1, SD3, SD5, and SD6 are interpreted within the cranked relativistic mean field theory by using the effective alignment method. High-N intruder configurations are also discussed for bands SD2 and SD4, based on a comparison of their dynamic moments of inertia, which rise with increasing rotational frequency, with those of similar bands in neighboring nuclei

Multiple excitation modes in Hf 163

Excited states of Hf163 were populated using the Zr94(Ge74,5n) reaction and the decay γ rays were measured with the Gammasphere spectrometer. Two previously known bands were extended to higher spins, and nine new bands were identified. In addition to bands associated with three- and five-quasiparticle configurations, two γ-vibrational bands coupled to the i13/2 excitation were also observed. The lowest level of a newly identified, negative-parity band is proposed to be the ground state of the nucleus. A systematic delay of the high-spin proton crossing frequency with increasing quadrupole deformation from Hf162 to Hf172 was established. Extensive band searches failed to reveal a triaxial, strongly deformed structure in Hf163 similar to the one observed in several nuclei around A∼165

Identification of triaxial strongly deformed bands in 164Hf

Two new rotational bands of distinct character have been identified in 164Hf. They are suggested to correspond to the long-anticipated triaxial strongly deformed (TSD) bands predicted by theoretical studies. The bands have been linked to known states, and the level spins and energies could be determined. The bands are also substantially stronger in intensity and are located at lower spins than the previously observed TSD bands in 168Hf, hereby making 164Hf the best even-even system so far for the study of TSD structures in the A∼160 mass region. Cranking calculations based on the modified-oscillator model suggest that the bands are associated with four-quasiparticle configurations that involve high-j intruder (i13/2)2 proton orbitals

Quadrupole moment measurements for strongly deformed bands in Hf171,172

A lifetime experiment, using the Doppler-shift attenuation method, has been performed at Gammasphere to measure the transition quadrupole moments Q t of strongly deformed bands in Hf171 and Hf172. The measured value of Qt ~ 9.5 e b for the band labeled ED in Hf171 strongly supports the recent suggestion that this sequence and several structures with similar properties in neighboring Hf isotopes are associated with a near-prolate shape with a deformation enhanced relative to that of normal deformed structures. The measured values of Qt- 14 e b for the bands labeled SD1 and SD3 in Hf172 confirm that these sequences are associated with a prolate superdeformed shape, a property inferred in earlier work from other measured characteristics of the bands. Similar bands in Hf173-175 are also likely to be associated with superdeformed shapes. The observations are in contrast to predictions of cranking calculations performed with the ultimate cranker code

High-spin proton alignments and evidence for a second band with enhanced deformation in 171Hf

High-spin properties of the nucleus 171Hf were studied through the 128Te(48Ca,5n) reaction. Previously known bands have been extended to significantly higher spins and four new bands have been extracted from these data. The results are discussed within the framework of the cranked shell model aided by a comparison with level structures in the neighboring nuclei. The band crossings at rotational frequencies ∼500 keV are interpreted as caused by the alignments of h11/2 and h9/2 proton orbitals. Band ED2 exhibits an alignment pattern similar to that of band ED1 which was reported in a recent paper and proposed to be built on a second potential energy minimum involving the deformation-driving proton i13/2 - h9/2 configuration. It is likely that band ED2 is also associated with a deformation enhanced with respect to that of the normal deformed structures. Further experimental investigation is needed to ascertain the nature of this band

High-spin proton alignments and coexisting coupling schemes in Hf168

High-spin states in Hf168 were populated in the Zr96(Ge76,4n) reaction and the decay γ rays measured with the Gammasphere spectrometer array. Previously known bands were extended to significantly higher spins and seven new bands were established. The results were interpreted within the framework of the cranked shell model with the help of comparisons with neighboring nuclei. The observation of full alignment in band crossings at a rotational frequency ω~0.55 MeV revealed that these crossings are associated with proton alignments involving h11/2 and h9/2 orbitals. The characteristics of one strongly coupled high-K band indicate that the deformation-aligned configuration is built on the same six quasiparticles that constitute the high-spin structure of a rotationally aligned band. This leads to the coexistence of two coupling schemes, deformation and rotation alignment, in six-quasiparticle structures involving the same orbitals

Nuclear shapes of highly deformed bands in Hf171,172 and neighboring Hf isotopes

A Gammasphere experiment was carried out to search for triaxial strongly deformed (TSD) structures in Hf171,172 and the wobbling mode, a unique signature of nuclei with stable triaxiality. Three strongly deformed bands in Hf172 and one in Hf171 were identified through Ca48(Te128, xn) reactions. Linking transitions were established for the band in Hf171 and, consequently, its excitation energies and spins (up to 111/2) were firmly established. However, none of the Hf172 sequences were linked to known structures. Experimental evidence of triaxiality was not observed in these bands. The new bands are compared with other known strongly deformed bands in neighboring Hf isotopes. Theoretical investigations within various models have been performed. Cranking calculations with the Ultimate Cranker code suggest that the band in Hf171 and two previously proposed TSD candidates in Hf170 and Hf175 are built on proton (i13/2h9/2) configurations, associated with near-prolate shapes and deformations enhanced with respect to the normal deformed bands. Cranked relativistic mean-field calculations suggest that band 2 in Hf175 has most likely a near-prolate superdeformed shape involving the πi13/2νj15/2 high-j intruder orbitals. It is quite likely that the bands in Hf172 are similar in character to this band