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Recently, results of a (p,t) experiment revealed 13 excited 0 ϩ states below ϳ3.2 MeV in 158 Gd. Such data provide a challenge to theory. We show calculations with the geometric collective model and the interacting boson approximation model that may account for many of these 0 ϩ states. The calculations suggest that many of the 0 ϩ states may be of two-phonon octupole character.

We study nuclear potential-energy surfaces, ground-state masses and shapes calculated by use of the Yukawa-plus-exponential macroscopic model and a folded-Yukawa single-particle potential for 4023 nuclei ranging from 16O to 279112. We present an overview of the results in the form of four colour contour diagrams vs. proton number Z and neutron number N. The four diagrams show calculated values of |ϵ2| and ϵ4 at the ground state, ground-state microscopic shell-plus-pairing corrections and the deviations between experimental and calculated masses. The diagrams vividly display the regions of magic and deformed nuclei. In particular, the plot of |ϵ2| vs. Z and N clearly shows the well-known deformed actinide and rare-earth regions and the two new deformed regions around A = 80 and A = 100. The plots indicate differences between the various deformed regions. For instance, there are differences in the magnitude of the deformation and in the character of the transition from spherical to deformed shapes. We discuss extensively the transition from spherical to deformed shapes and study the relation between shape changes and the mass corresponding to the ground-state minimum, and the significance of additional minima in the nuclear potential-energy surface. For a few illustrative cases we discuss the effect of angular momentum on the nuclear shape. The calculated values for the ground-state mass and shape show good agreement with experimental data throughout the periodic system, but some discrepancies remain that deserve further study.

High-spin states in the doubly-odd Z = 77 nucleus 188 Ir were populated in the 186 W͑ 7 Li,5n͒ reaction at 52 MeV. Two nearly degenerate ⌬I = 1 sequences with the same parity were established. Both bands have been assigned the h 9/2 i 13/2 configuration, based on the systematic behavior of these excitations in the Ir nuclei and on the measured values for the B͑M1͒ / B͑E2͒ ratios, and they are suggested as candidates for a chiral doublet.

Yrast superdeformed bands for even-even nuclei of the mass-190 region are described by the projected shell model. Excellent agreement with available data for all isotopes is obtained. Our calculation of electromagnetic properties and pairing correlations provides a microscopic understanding of the observed gradual increase of dynamical moments of inertia with angular momentum in this mass region and suggests that for superdeformation it is not very meaningful to distinguish between Coriolis antipairing and gradual high-j orbital alignment. [S0031-9007(97)02692-6] PACS numbers: 21.10. Re, 21.30.Fe, 21.60.Cs, 27.80. + w A slowly rotating nuclear system can often be characterized by a fixed deformation with pairing correlation among nucleons. As the system rotates more rapidly, these 2 degrees of freedom will be modified by the rotation. Three simple consequences may be identified: (1) the nuclear deformation can vary during the rotation, a phenomenon known as the stretching effect [1]; (2) the Coriolis antipairing effect (CAP) [2], which is caused by the weakening pairing correlations across many orbitals due to the Coriolis force; and (3) rotation alignment [3], which emphasizes an alignment along the rotation axis of a pair in an orbital particularly susceptible to the Coriolis effect. All these effects can lead to a variation in moment of inertia (MoI).Generally, all of these effects may be expected in rotating nuclear systems, but in special cases one of them may dominate. For example, in rare-earth nuclei the observed sudden enhancement in the MoI associated with a backbend is typically dominated by rotation alignment of a nucleon pair from a high-j and low-V orbital [3], with CAP and stretching effects playing less important roles. However, for situations where the variation in the MoI is gradual, the measured g-ray energies are often not sufficient to distinguish the effects that change the MoI. Additional measurements of transition quadrupole moments, g factors, or nucleon pair transfer reactions can provide information to disentangle these contributions, but these are more difficult than energy measurements.The situation for superdeformed (SD) nuclei is less clear. In the SD nuclei of the mass-190 region, both kinematical ͑J ͑1͒ ͒ and dynamical ͑J ͑2͒ ͒ MoI for most SD bands exhibit a gradual increase as a function of increasing rotational frequency, with a more pronounced increase in J ͑2͒ . Thus, even though these are among the most deformed nuclei, they exhibit substantial deviation from rigid rotor behavior as the angular momentum increases. The usual understanding is that this behavior is caused by a gradual rotation alignment of pairs from high-j intruder orbitals [4]. There have been several approaches to the detailed calculation of SD bands and their properties [5][6][7][8][9][10][11][12]. Although these differ in particulars, a common feature is that the rotational degree of freedom is described by the cranking method. Thus no electromagnetic transition probabilities as a function of angular momen...

Fluorescent probes have emerged as an essential tool in the molecular recognition events in biological systems; however, due to the complex structures of certain biomolecules, it remains a challenge to design small-molecule fluorescent probes with high sensitivity and selectivity. Inspired by the enzyme-catalyzed reaction between biomolecule and probe, we present a novel combination-reaction two-step sensing strategy to improve sensitivity and selectivity. Based on this strategy, we successfully prepared a turn-on fluorescent reduced nicotinamide adenine dinucleotide (NADH) probe, in which boronic acid was introduced to bind with NADH and subsequently accelerate the sensing process. This probe shows remarkably improved sensitivity (detection limit: 0.084 μM) and selectivity to NADH in the absence of any enzymes. In order to improve the practicality, the boronic acid was further modified to change the measurement conditions from alkalescent (pH 9.5) to physiological environment (pH 7.4). Utilizing these probes, we not only accurately quantified the NADH weight in a health care product but also evaluated intracellular NADH levels in live cell imaging. Thus, these bio-inspired fluorescent probes offer excellent tools for elucidating the roles of NADH in biological systems as well as a practical strategy to develop future sensitive and selective probes for complicated biomolecules.

Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F,4n)134Pr. Recoil distance Doppler-shift and Doppler-shift attenuation measurements using the Euroball spectrometer, in conjunction with the inner Bismuth Germanate ball and the Cologne plunger, were performed at beam energies of 87 MeV and 83 MeV, respectively. Reduced transition probabilities in 134Pr are compared to the predictions of the two quasiparticle + triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134Pr can be supported.

A theranostic probe is designed that specifically illuminates and photoablates cancer cells by sensing pH changes in the lysosomes and mitochondria.