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Combining the experimental a-decay energies and half-lives, the a-particle preformation factors for the nuclei around A' = Z = 50 are extracted within the generalized liquid drop model. It is found that the average order of magnitude of the preformation factor is 1.0 x 10-1. In addition, a detailed discussion on the odd-even effect of the preformation factor is performed. [ABSTRACT FROM AUTHOR]

In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+T, SLy5+Tw and several sets of the TIJ parametrizations, the evolution of the proton single-particle energy difference between the 2s 1/2 and 1d3/2 orbits in Ca isotopes is investigated for the cases with and without the tensor force. It is shown that the energy difference evolution trends by using different Skyrme interactions without the tensor force are similar to each other. However, the energy differences are obviously influenced by the tensor force. Meanwhile, it is found that the inversion between the two orbits (2s1/2-1d3/2 inversion) induced by the tensor force occurs around 48Ca (by SLy5+Tw) as well as in the nuclei very far from the stability. We understand the inversion phenomenon by analyzing the tensor contributions to the spin-orbit potentials and the radial wave functions of the two orbits. Finally, the proton density distributions of 46Ar and 206Hg are calculated by using several sets of Skyrme interactions with and without the tensor component. It is found that the parametrization SLy5+Tw favors the bubble structure of 46Ar resulting from the 2s1/2-1d3/2 inversion. However, for 206Hg any tensor parametrizations do not favor its bubble structure. [ABSTRACT FROM AUTHOR]

Systematic calculations on the a-decay energies (Qa) and a-decay half-lives of the superheavy nuclei (SHN) with Z ≥ 100 are performed by using 20 models and 18 empirical formulas, respectively. According to the comparisons between the calculated results and experimental data, it is shown that the WS4 mass model is the most accurate one to reproduce the experimental Qa values of the SHN. Meanwhile it is found that the SemFIS2 formula is the best one to predict the a-decay half-lives of the SHN because the parameters in this formula are from the experimental a emitter data of transuranium nuclei including SHN (Z = 92-118). In addition, the UNIV2 formula with fewest parameters and the VSS, SP and NRDX formulas with fewer parameters work well in prediction on the SHN a-decay half-lives. Finally, the a-decay half-lives of Z = 110-120 isotopes are predicted within the above mentioned five formulas by inputting the WS4 Qa values. By analyzing the Qa values and the a-decay half-lives of this region, it is found that for Z = 110-114 isotopes N = 162 and N = 184 are the submagic number and magic number, respectively. However, for the isotopes of Z = 116-120 the submagic number is N = 178. [ABSTRACT FROM AUTHOR]

The proton density distribution of 206Hg is calculated in the framework of the Skyrme-Hartree-Fock approach with the SLy5, SLy5+T, and SLy5+Tw interactions. It is shown that the central density drops strongly with the SLy5 and SLy5+T interactions due to the vacancy of the 3s1/2 orbital. This means that the density depression in the interior of the nucleus is not so much influenced by the tensor force of the SLy5+T interaction. However, with the SLy5+Tw interaction the bubble structure does not exist because the tensor force effect of this interaction leads to the inversion between the single-proton states 3s1/2 and 1h11/2 (3s1/2-1h11/2 inversion) so that the 3s1/2 state is fully occupied by protons. In addition, a detailed discussion on the antibubble effect from the pairing interaction is performed by using the Skyrme-Hartree-Fock-Bogoliubov approach. It is found that a proton bubble structure in Hg206 is unlikely to appear because of the paring correlation. [ABSTRACT FROM AUTHOR]

Abstract: The low-spin part of the nucleus was investigated in radioactive decay of . The decay scheme was established and for a number of levels spin-parity assignments are suggested on the basis of logft values and γ-branching ratios. In order to discuss the band structures of this nucleus, the projected shell model is applied to the nucleus . The results of theoretical calculations about the excited positive-parity yrast states and the negative-parity ground-state band are compared with experimental data, and the best reproduction of the experiment has been given by this model. In addition, a band diagram calculated for the negative-parity g.s. band is used in order to extract physics out of the numerical results. [Copyright &y& Elsevier]

The charge-symmetry-breaking (CSB) effect in a nuclear medium that gives rise to the first-order symmetry energy in finite nuclei is discussed in detail in the present paper. For heavy and superheavy nuclei with large neutron excesses, it should be nonnegligible in high-precision mass predictions, and importantly it affects the stability of these nuclei. Combined with this CSB effect, the Coulomb energy is constrained by using the experimental Coulomb displacement energy of mirror nuclei, and then the mass-dependent symmetry energy coefficients of heavy nuclei are reextracted with the experimental β--decay energies of heavy odd-A nuclei and with the experimental mass differences. Based on these results, we probe the neutron skin thickness ΔRnp of 208Pb and the density-dependent symmetry energy coefficient of nuclear matter. ΔRnp in 208Pb is found to be 0.158±0.014fm, and the slopes L of the symmetry energy coefficient at densities of ρ=0.16 and ρ=0.11fm-3 are estimated to be 42±8 and 42±3MeV, respectively. These results would be meaningful to discriminate between the models and the predictions that are relevant for the investigations on properties of nuclei and of neutron stars. [ABSTRACT FROM AUTHOR]

Objective: In order to search a safer argon laser photodynamic method, this study used 488 nm wavelength and common mixed spectrum argon laser PDT for treating Port Wine Stain. The therapeutic effects and side effect were compared., Methods: Fifty two cases of PWS were divided into two groups randomly. Argon laser PDT by two ways of laser irradiation were used., Results: Our data revealed 19.23% cure rate in 488 nm laser PDT group, while that of mixed wavelength laser group was 11.54%. There was no significant difference in the two groups. Also the effective rate of 488 nm laser group was 92.31% and that of mixed group was 88.46%. But the difference was not significant statistically. Side effect occurred often in mixed spectrum laser group. That was 57.69% for mixed group, 38.46% for 488 nm group., Conclusion: Argon laser PDT at 488 nm had the similar therapeutic result contrasted to mixed spectrum laser group, but it was safe.

A major obstacle in positional cloning is identifying the specific mutated gene from within a large physical contig. Here we describe the application of DNA microarray technology to a defined genomic region (physical map) to identify: (i) exons without a priori sequence data and (ii) the disease gene based on differential gene expression in a recessive disorder. The feasibility was tested using resources from the positional cloning of the Neimann-Pick Type C (NP-C) disease gene, NPC1. To identify NPC1 exons and optimize the technology, an array was generated from genomic fragments of the 110-kb bacterial artificial chromosome, 108N2, which encodes NPC1. First, as a test case for blindly identifying exons, fluorescently labeled NPC1 cDNA identified 108N2 fragments that contained NPC1 exons, many of which also contained intronic sequences and could be used to determine part of the NPC1 genomic structure. Second, to demonstrate that the NPC1 disease gene could be identified based upon differential gene expression, subarrays of 108N2 fragments were hybridized with fluorescently labeled cDNA probes generated from total RNA from hamster cell lines differentially expressing NPC1. A probe derived from the NP-C cell line CT60 did not detect NPC1 exons or other genomic fragments from 108N2. In contrast, several NPC1 exons were detected by a probe generated from the non-NP-C cell line 911D5A13, which was derived from CT60, and expressed NPC1 as a consequence of stable transduction with a YAC that contains NPC1 and encompasses 108N2. Thus, the array technology identified NPC1 as a candidate gene based on a physical contig and differential NPC1 expression between NP-C and non-NP-C cells. This technique should facilitate gene identification when a physical contig exists for a region of interest and mutations result in changes in the mRNA level of the disease gene or portions thereof., (Copyright 2000 Academic Press.)

OBJECTIVE:There were 13 cases underwent operation.24 cases underwent cryosurgery only and 70 cases received comprehensive management,which as cryosurgery,operation,chemotherapy and immuno-therapy.RESULTS:The 3'and 5' year survival rate of three groups were 0.0%,0.0%,37.50%,31.25% and 57.14%,36.07%.There are significant differences between operation group and cryosurgery group and between operation group and comprehensive treatment group.Although the third group got the better result,but the difference between late two groups was not statistical significant.CONCLUSION:It is suggested that comprehensive treatment be the routine regime of melanoma in head and neck. Our experience with review of literature covered the classification, surgical principle and complication was presented.