313 research outputs found

    Microscopic Structure of High-Spin Vibrational Excitations in Superdeformed 190,192,194Hg

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    Microscopic RPA calculations based on the cranked shell model are performed to investigate the quadrupole and octupole correlations for excited superdeformed bands in 190Hg, 192Hg, and 194Hg. The K=2 octupole vibrations are predicted to be the lowest excitation modes at zero rotational frequency. At finite frequency, however, the interplay between rotation and vibrations produces different effects depending on neutron number: The lowest octupole phonon is rotationally aligned in 190Hg, is crossed by the aligned two-quasiparticle bands in 192Hg, and retains the K=2 octupole vibrational character up to the highest frequency in 194Hg. The gamma vibrations are predicted to be higher in energy and less collective than the octupole vibrations. From a comparison with the experimental dynamic moments of inertia, a new interpretation of the observed excited bands invoking the K=2 octupole vibrations is proposed, which suggests those octupole vibrations may be prevalent in SD Hg nuclei.Comment: 22 pages, REVTeX, 12 postscript figures are available on reques

    Spectral Lag Relations in GRB Pulses Detected with HETE-2

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    Using a pulse-fit method, we investigate the spectral lags between the traditional gamma-ray band (50-400 keV) and the X-ray band (6-25 keV) for 8 GRBs with known redshifts (GRB 010921, GRB 020124, GRB 020127, GRB 021211, GRB 030528, GRB 040924, GRB 041006, GRB 050408) detected with the WXM and FREGATE instruments aboard the HETE-2 satellite. We find several relations for the individual GRB pulses between the spectral lag and other observables, such as the luminosity, pulse duration, and peak energy (Epeak). The obtained results are consistent with those for BATSE, indicating that the BATSE correlations are still valid at lower energies (6-25 keV). Furthermore, we find that the photon energy dependence for the spectral lags can reconcile the simple curvature effect model. We discuss the implication of these results from various points of view.Comment: 13 pages, 9 figures, accepted for the publication in PASJ (minor corrections

    How should tracers be injected to detect for sentinel nodes in gastric cancer – submucosally from inside or subserosally from outside of the stomach?

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    <p>Abstract</p> <p>Background</p> <p>In sentinel node (SN) detection for cases of early gastric cancer, the submucosal dye injection method appears to be more reasonable than the subserosal injection. To compare the two injection methods, we have focused on the rate of concordance between hot nodes (HNs) obtained from the radioisotope (RI) method and green nodes (GNs) obtained from the dye-guided method in addition to the number and distribution of GNs detected, and the sensitivity of metastatic detection.</p> <p>Methods</p> <p>The subjects of this study were 63 consecutive patients with gastric cancer (sT1–T2, sN0, tumor diameter ≩ 4 cm) in whom we attempted SN detection using a combination of RI and dye methods. <sup>99m</sup>Tc-tin colloid was injected a day before the surgery, and indocyanine green was injected either submucosally (n = 43) with endoscopes or subserosally (n = 20) by direct vision.</p> <p>Results</p> <p>An average of hot and green nodes (H&G: 4 ± 3 vs. 4 ± 3), hot and non-green nodes (H&NG: 2 ± 3 vs. 1 ± 2), cold and green nodes (C&G: 2 ± 2 vs. 3 ± 4), and the rate of concordance (H&G/H&G + H&NG + C&G: 45 + 27% vs. 48 ± 30%) were not significantly different between the submucosal and subserosal injection methods. The spread of GNs to tier 2 stations (24% vs. 30%) and metastatic detection sensitivity (86% vs. 100%) were also not different between the submucosal and subserosal injection methods.</p> <p>Conclusion</p> <p>The tracer injection sites do not have to be limited to the submucosa.</p

    Expression of transient receptor potential channel vanilloid (TRPV) 1–4, melastin (TRPM) 5 and 8, and ankyrin (TRPA1) in the normal and methimazole-treated mouse olfactory epithelium

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    Conclusion: It is suggested that TRPV1, 2, 3, and 4, TRPM5 and 8, and TRPA1 may play several roles in the olfactory epithelium (OE), contributing to olfactory chemosensation, olfactory adaptation, olfactory-trigeminal interaction, and OE fluid homeostasis. In patients with olfactory disturbance, TRPV1 and TRPM8 may be closely related to a high rate of recognition of curry and menthol odors, while TRPV2 may also play a crucial role in the regeneration of olfactory receptor neurons. Objective: Expression of TRPV1–4, TRPM5 and 8, and TRPA1 in the normal and methimazole-treated mouse OE was analyzed. Methods: The localization of TRPV1–4, TRPM5 and 8, and TRPA1 in the OE of normal and methimazole-treated CBA/J mice was investigated by immunohistochemistry. Results: Normal OE showed a positive immunofluorescent reaction to TRPV1–4, TRPM5 and 8, and TRPA1. In lamina propria, the nerve fibers displayed TRPV 1, 2, and 3, TRPM8 and TRPA1. In the pathological condition, the expression of TRPV3, TRPV4, TRPM5, and TRPA1 was markedly reduced and took a long time to recover. In contrast, expression of TRPM8 was scarcely affected, even in the pathological condition, while TRPV1 and TRPV2 showed early recovery following methimazole treatment

    Dietary fiber showed no preventive effect against colon and rectal cancers in Japanese with low fat intake: an analysis from the results of nutrition surveys from 23 Japanese prefectures

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    BACKGROUND: Since Fuchs' report in 1999, the reported protective effect of dietary fiber from colorectal carcinogenesis has led many researchers to question its real benefit. The aim of this study is to evaluate the association between diet, especially dietary fiber and fat and colorectal cancer in Japan. METHODS: A multiple regression analysis (using the stepwise variable selection method) was performed using the standardized mortality ratios (SMRs) of colon and rectal cancer in 23 Japanese prefectures as objective variables and dietary fiber, nutrients and food groups as explanatory variables. RESULTS: As for colon cancer, the standardized partial correlation coefficients were positively significant for fat (1,13, P = 0.000), seaweeds (0.41, P = 0.026) and beans (0.45, P = 0.017) and were negatively significant for vitamin A (-0.63, P = 0.003), vitamin C (-0.42, P = 0.019) and yellow-green vegetables (-0.37, P = 0.046). For rectal cancer, the standardized partial correlation coefficient in fat (0.60, P = 0.002) was positively significant. Dietary fiber was not found to have a significant relationship with either colon or rectal cancers. CONCLUSIONS: This study failed to show any protective effect of dietary fiber in subjects with a low fat intake (Japanese) in this analysis, which supports Fuchs' findings in subjects with a high fat intake (US Americans)

    Flat-band ferromagnetism in quantum dot superlattices

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    Possibility of flat-band ferromagnetism in quantum dot arrays is theoretically discussed. By using a quantum dot as a building block, quantum dot superlattices are possible. We consider dot arrays on Lieb and kagome lattices known to exhibit flat band ferromagnetism. By performing an exact diagonalization of the Hubbard Hamiltonian, we calculate the energy difference between the ferromagnetic ground state and the paramagnetic excited state, and discuss the stability of the ferromagnetism against the second nearest neighbor transfer. We calculate the dot-size dependence of the energy difference in a dot model and estimate the transition temperature of the ferromagnetic-paramagnetic transition which is found to be accessible within the present fabrication technology. We point out advantages of semiconductor ferromagnets and suggest other interesting possibilities of electronic properties in quantum dot superlattices.Comment: 15 pages, 7 figures (low resolution). High-resolution figures are available at http://www.brl.ntt.co.jp/people/tamura/Research/PublicationPapers.htm

    Studies on a Medicinal Parasitic Plant: Lignans from the Stems of Cynomorium songaricum

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    Eight phenolic compounds including two new lignan glucopyranosides together with a known alkaloid were isolated from the stems of Cynomorium songaricum RUPR. (Cynomoriaceae). Their chemical structures were elucidated on the basis of spectral and chemical evidence. The chemotaxonomic significance of these metabolites is discussed
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