Occupancy of orbitals and the quadrupole collectivity in 45Sc nucleus

In the present work, the Doppler Shift Attenuation method (DSAM) was used to analyze the observed lineshapes of transitions from excited states in ⁴⁵Sc, populated in the reaction ³⁶Ar + ¹²C at a beam energy of 145 MeV. The interpretation and comparison of the experimental results have been performed with large-scale shell model calculations, involving different interactions like: GX1A, GX1J, FPD6, KB3 and ZBM2. KB3 and FPD6 (present work) interactions in the negative parity states, and in positive parity states ZBM2 are most pre-eminent in reproducing the results, due to the large configuration space describing strong collective effects. Furthermore, the present work also looks at the details of the shell model helping in improving the understanding for the occupancy of orbitals. The present investigation suggests the observation of stronger collectivity for positive parity states over negative parity states with predicted enhanced collectivity of states in ⁴⁵Sc nucleus.

Probing ^{93m}Mo Isomer Depletion with an Isomer Beam

The isomer depletion of ^{93m}Mo was recently reported [Chiara et al., Nature (London) 554, 216 (2018)NATUAS0028-083610.1038/nature25483] as the first direct observation of nuclear excitation by electron capture (NEEC). However, the measured excitation probability of 1.0(3)% is far beyond the theoretical expectation. In order to understand the inconsistency between theory and experiment, we produce the ^{93m}Mo nuclei using the ^{12}C(^{86}Kr,5n) reaction at a beam energy of 559 MeV and transport the reaction residues to a detection station far away from the target area employing a secondary beam line. The isomer depletion is expected to occur during the slowdown process of the ions in the stopping material. In such a low γ-ray background environment, the signature of isomer depletion is not observed, and an upper limit of 2×10^{-5} is estimated for the excitation probability. This is consistent with the theoretical expectation. Our findings shed doubt on the previously reported NEEC phenomenon and highlight the necessity and feasibility of further experimental investigations for reexamining the isomer depletion under low γ-ray background.

Lifetime Measurements of Excited States in ^{172}Pt and the Variation of Quadrupole Transition Strength with Angular Momentum

Lifetimes of the first excited 2^{+} and 4^{+} states in the extremely neutron-deficient nuclide ^{172}Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+})=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

Emulsified isoflurane postconditioning produces cardioprotection against myocardial ischemia-reperfusion injury in rats

Emulsified isoflurane (EIso) preconditioning can induce cardioprotection. We investigated whether EIso application after ischemia protects hearts against reperfusion injury and whether it is mediated by the inhibition of apoptosis. Rats were subjected to 30-min coronary occlusion followed by 180-min reperfusion. At the onset of reperfusion, rats were intravenously administered saline (sham, control group), 30 % intralipid (IL group) or 2 ml kg(-1) EIso (EIso group) for 30 min. After reperfusion, infarct sizes, myocardial apoptosis and expression of Bcl-2, Bax and caspase-3 proteins were determined. Hemodynamic parameters were not different among groups. Compared with control and intralipid group, EIso limited infarct size, inhibited apoptosis, increased the expression of Bcl-2, decreased the expression of Bax, cleaved caspase-3, and enhanced Bcl-2/Bax ratio. EIso protects hearts against reperfusion injury when administered at the onset of reperfusion, which may be mediated by the inhibition of apoptosis via modulation of the expression of pro- and anti-apoptotic proteins.

[The influence of microtubule intervention drugs on glycolytic key enzymes in myocardial cells after hypoxia]

OBJECTIVE

To investigate the influence of microtubule intervention drugs on glycolytic key enzymes in myocardial cells after hypoxia.

METHODS

The primary passage of cultured myocardial cells from neonatal rats were divided into A group (with hypoxia), B group (with hypoxia and administration of l0 micromol/L colchicine), C group (with hypoxia and administration of 5 micromol/L taxol), D group (with hypoxia and administration of 10 micromol/L taxol), E group (with hypoxia and administration of 15 micromol/L taxol). The morphology of microtubule was observed with laser scanning microscope (LSM). The cell vitality was assayed by cell counting kit (CCK). The activities of hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) were assayed with colorimetry.

RESULTS

In group B and E, the microtubule structure was damaged heavily, and the cell vitality was decreased significantly [The cell vitality was (89.99 +/- 3.47)% in B group and (84.56 +/- 6.61)% in E group, respectively, at 1.0 post hypoxia hour (PHH), and hoth values were obviously lower than that in A group (97.44 +/- 1.76)%, P < 0.01]. The HK, PK and PFK activities decreased obviously. The activities of HK, PK and PFK in group C were similar to those of the A group. Compared with that in other groups, the degree of damage of microtubule structure in D group was milden. The activities of HK, PK and PFK in D group during 0.5 - 6.0 PHH were significantly higher than those in A group. The activity of LDH in each group was increased after hypoxia.

CONCLUSION

Proper concentration of microtubule-stabilizing drugs can alleviate the damages to microtubule structure, and enhance the activity of glycolytic key enzymes of myocardial cells at early stage of hypoxia.

[Construction of a transformation-competent artificial chromosome (TAC) library of a wheat-Haynaldia villosa translocation line]

Transformation-competent artificial chromosome (TAC) vector is able to clone and transfer large DNA fragments in plants and is a powerful tool for plant gene isolation and transformation. To clone important genes from wheat, a TAC genomic library was constructed from nuclear DNA of a 6VS/6AL wheat-Haynaldia villosa translocation line that harbor the gene Pm21 for resistance to powdery mildew. The library consists of 2.1 x 10(6) clones with an average DNA insert size of 35 kb, and represents in total 4.9 genome equivalents. The library was stored as clone pools in 96-well plates, and each pool contained about 1000 clones. TAC clones containing gene(s) of interest can be screened by a pooled-PCR/colony-hybridization strategy.