A Classical Approach to Nuclear Instability

We extend a classical model of nuclei to include geometry as well as electron-like shells, then apply the model to the moments leading up to nuclear decay. The model leads to the well-known half-life or constant probability of a given nucleus to decay in a given time.

Ground-state and isomeric-state cross-sections for 92Mo(n,α)89Zr and 95Mo(n,p)95Nb reactions in the 13–15 MeV energy region

The (n,α) and (n,p) cross-sections and their isomeric ratios (σ m /σ g ) were measured at 13–15 MeV for 92Mo and 95Mo by activation and off-line γ-ray spectrometry. The activated Mo samples combined with Al foils were used to obtain the cross-section values and the neutron flux, generated using the 3H(d,n)4He reaction. The cross-sections of the ground states were obtained using the metastable state absolute cross-sections and the residual nuclear decay rule. The excitation functions, total cross-sections, and isomeric ratios for the 92Mo(n,α)89m,gZr and 95Mo(n,p)95m,gNb reactions were calculated using the TALYS-1.95 software. 92Mo(n,α)89m + gZr and 95Mo(n,p)95m + gNb reaction excitation functions were obtained using the EMPIRE-3.2.3 package. These simulation results were compared with the corresponding experimental data and with the evaluated data from the ENDF/B-VIII.0, JEFF-3.3, CENDL-3, and ROSFOND libraries. Only partial agreements were observed.

Dynamics of nuclear recoil: QM-MD simulations ofmodel systems following β-decay

The kinetic recoil energy received by the daughter nucleus in a nuclear decay is often large enough to affect the structure around the nucleus in chemical systems. The coinciding element change...

Rrp6p/Rrp47p constitutes an independent nuclear turnover system of mature small non-coding RNAs in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, the nuclear exosome/Rrp6p/TRAMP participates in the 3'-end processing of several precursor non-coding RNAs. Here we demonstrate that the depletion of nucleus-specific 3'to 5' exoribonuclease Rrp6p and its co-factor Rrp47p led to the specific and selective enhancement of steady-state levels of mature small non-coding RNAs (sncRNAs) that include 5S and 5.8S rRNAs, snRNAs and snoRNAs, but not 18S and 25S rRNAs. Most importantly, their steady-state enhancement does not require the exosome, TRAMP, CTEXT or Rrp6p-associated Mpp6p. Rrp6p/47p-dependent enhancement of the steady-state levels of sncRNAs is associated with the diminution of their nuclear decay-rate and requires their polyadenylation before targeting by Rrp6p, which is catalyzed by both the canonical and non-canonical poly(A) polymerases, Pap1p and Trf4p. Consistent with this finding, the Rrp6p and Rrp47p were demonstrated to exist as an exosome-independent complex. Thus, Rrp6p-Rrp47p defines a core nuclear exosome-independent novel turnover system that targets the small non-coding RNAs.