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71.
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The Heck reaction of an unsymmetrically substituted [3]cumulene has been investigated. Although a carbonyl conjugated alkene is present, the arylpalladium species selectively inserts into the C3-4 double bond, and a subsequent C-H activation reaction with a neighboring phenyl group gives the indene derivatives with a tetrasubstituted olefin moiety.  相似文献   
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We performed an improved search for nu(mu) --> nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2 x 10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu) --> nu(e) oscillation parameters. At Deltam(2)=2.8 x 10(-3) eV(2), the best-fit value of the K2Knu(mu) disappearance analysis, we set an upper limit of sin(2)2theta(mue) < 0.13 at a 90% confidence level.  相似文献   
75.
Four new resveratrol derivatives, upunaphenols B (1), C (4), D (5) (resveratrol tetramer) and E (6, resveratrol dimer with a C6-C1 unit), together with nine known resveratrol oligomers and resveratrol were isolated from an acetone soluble part of stem of Upuna borneensis (Dipterocarpaceae). The structures of new compounds were determined by spectral analysis including 1D and 2D NMR experiments.  相似文献   
76.
We have performed a series of experiments to observe 11 Stark-induced E1 transitions from the 15650.55 cm-1 level to higher levels with odd parity in samarium (Sm) with optical double-resonance technique. Five Stark-induced E1 transition to the 28233.08, 28613.22, 28913.97, 29041.31 and 29130.03 cm-1 levels have been observed. In order to investigate the contributors to the Stark-induced E1 transition, we have measured scalar and tensor polarizabilities for the observed Stark-induced E1 transitions. Clear Stark splittings were observed for the levels 28233.08 and 28613.22 cm-1, and their tensor polarizabilities were determined for each isotope. Scalar polarizabilities were determined for the 28233.08, 28613.22, 28913.97 and 29130.03 cm-1 levels for the first time. Among them, scalar polarizability for the 28233.08 cm-1 level was the largest in magnitude and was 3.60(10) x 103 kHz/(kV/cm)2 for Sm. We noticed that both scalar and tensor polarizabilities of the 28233.08 cm-1 level depend on the isotope; the difference of magnitude of the scalar and tensor polarizabilities between Sm and Sm were remarkably large and were about 10 and 6 percent, respectively.Received: 10 February 2003, Published online: 30 July 2003PACS: 32.60.+i Zeeman and Stark effects - 32.10.Dk Electric and magnetic moments, polarizabilityD. Angom: Present address: Physical Research Laboratory, Navarangpura, Ahmedabad 380 009, India.  相似文献   
77.
Three new trimeric stilbenes from Gnetum gnemon   总被引:1,自引:0,他引:1  
Three stilbene trimers (gnemonols D, E, F) were isolated from the root of Gnetum gnemon. The structures were determined by spectroscopic analysis. In addition, the antioxidant activity of the compounds on lipid peroxide inhibition and super oxide scavenging activity were also investigated.  相似文献   
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The value of preoperative bone scans in patients with primaly breast and prostate cancer was evaluated prospectively. The methodology and some clinical results were described previously. The clinical efficacy of the bone scan was assessed by using ROC analysis and we obtained the following results. 1) Preoperative bone scan of carcinomas of the breast is effective for patients with clinical stage IIIA, IIIB and IV. It is not so effective for patients with clinical stage I and II, but there is no denying the importance of it, because it provides a base-line scan for comparison to subsequent scans obtained in the postoperative period. 2) Preoperative bone scan of prostate carcinomas is effective, especially for clavicle, the ribs and the cervical spine, when compared with bone X-ray. 3) Bone scan is effective means for patients who were diagnosed uncertainly to have bone metastasis.  相似文献   
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