301 research outputs found
mRNA of bovine tissue inhibitor of metalloproteinase: Sequence and expression in bovine ovarian tissue
Characterization by cDNA cloning of the mRNA for seminalplasmin, the major basic protein of bull semen.
A cDNA library derived from poly(A)+RNA of bull seminal vesicle tissue was screened with synthetic DNA probes specific for seminalplasmin (SAP), the major basic protein of bull semen. From a number of positive clones, pBSV12, containing a 577-bp insert, was identified and sequenced. The derived amino acid sequence comprises the known amino acid sequence of SAP with an amino terminal representing a putative signal sequence; at the carboxyl terminus the sequence contains an additional lysine residue. Present experimental data do not distinguish between two potential SAP precursor molecules, each starting with a methionine residue and differing by 10 amino acid residues in the leader peptide. Comparative Northern analysis reveals a SAP-specific mRNA of 700 bp, which lacks RNA from bovine testis as well as from seminal vesicle tissue of a bull calf; hence, expression of the SAP gene appears to be under androgen and/or developmental control. Southern analysis indicates that one gene appears to specify SAP. SAP-like DNA sequences were detected in ovine and porcine genomic DNA
Bremsstrahlung in alpha-Decay Reexamined
A high-statistics measurement of bremsstrahlung emitted in the alpha decay of
210Po has been performed, which allows to follow the photon spectra up to
energies of ~ 500 keV. The measured differential emission probability is in
good agreement with our theoretical results obtained within the quasi classical
approximation as well as with the exact quantum mechanical calculation. It is
shown that due to the small effective electric dipole charge of the radiating
system a significant interference between the electric dipole and quadrupole
contributions occurs, which is altering substantially the angular correlation
between the alpha particle and the emitted photon.Comment: 10 pages, 5 figures, v2: fix of small typo
Seminalplasmin, the major basic protein of bull seminal plasma, is a secretory protein of the seminal vesicles.
Neutron radioactivity—Lifetime measurements of neutron-unbound states
A new technique to measure the lifetime τ of a neutron-radioactive nucleus that decays in-flight via neutron emission is presented and demonstrated utilizing MonteCarlo simulations. The method is based on the production of the neutron-unbound nucleus in a target, which at the same time slows down the produced nucleus and the residual nucleus after (multi-) neutron emission. The spectrum of the velocity difference of neutron(s) and the residual nucleus has a characteristic shape, that allows to extract the lifetime. If the decay happens outside the target there will be a peak in the spectrum, while events where the decay is in the target show a broad flat distribution due to the continuous slowing down of the residual nucleus. The method itself and the analysis procedure are discussed in detail for the specific candidate 26O. A stack of targets with decreasing target thicknesses can expand the measurable lifetime range and improve the sensitivity by increasing the ratio between decays outside and inside the target. The simulations indicate a lower limit of measurable lifetime τ∼0.2 ps for the given conditions
Exploring Neutron-Rich Oxygen Isotopes with MoNA
The Modular Neutron Array (MoNA) was used in conjunction with a large-gap
dipole magnet (Sweeper) to measure neutron-unbound states in oxygen isotopes
close to the neutron dripline. While no excited states were observed in 24O, a
resonance at 45(2) keV above the neutron separation energy was observed in 23O.Comment: 6 pages, 4 Figures, submitted to Proc. Int. Conf. on Proton Emitting
Nuclei and Related Topics, PROCON0
Bremsstrahlung in α decay reexamined
A high-statistics measurement of bremsstrahlung emitted in the α decay of 210Po has been performed, which allows us to follow the photon spectra up to energies of ~500keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasiclassical approximation as well as with the exact quantum mechanical calculation. It is shown that, due to the small effective electric dipole charge of the radiating system, a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the α particle and the emitted photon
Time-Resolved Measurement of Interatomic Coulombic Decay in Ne_2
The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al.,
Phys. Rev. Lett. 79, 4778 (1997)] in Ne_2 is determined via an extreme
ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The
pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms,
whereupon the ionized dimer undergoes ICD resulting in a repulsive
Ne^{+}(2p^{-1}) - Ne^{+}(2p^{-1}) state, which is probed with a second pulse,
removing a further electron. The yield of coincident Ne^{+} - Ne^{2+} pairs is
recorded as a function of the pump-probe delay, allowing us to deduce the ICD
lifetime of the Ne_{2}^{+}(2s^{-1}) state to be (150 +/- 50) fs in agreement
with quantum calculations.Comment: 5 pages, 3 figures, accepted by PRL on July 11th, 201
Structural evolution in the neutron-rich nuclei 106Zr and 108Zr
The low-lying states in 106Zr and 108Zr have been investigated by means of
{\beta}-{\gamma} and isomer spectroscopy at the RI beam factory, respectively.
A new isomer with a half-life of 620\pm150 ns has been identified in 108Zr. For
the sequence of even-even Zr isotopes, the excitation energies of the first 2+
states reach a minimum at N = 64 and gradually increase as the neutron number
increases up to N = 68, suggesting a deformed sub-shell closure at N = 64. The
deformed ground state of 108Zr indicates that a spherical sub-shell gap
predicted at N = 70 is not large enough to change the ground state of 108Zr to
the spherical shape. The possibility of a tetrahedral shape isomer in 108Zr is
also discussed.Comment: 10 pages, 3 figures, Accepted for publication in Phys. Rev. Let
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