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41.
Nomura Y Inoue Y Yokoyama I Nakaoka T Itoh D Okubo T Ohtomo K 《Magnetic resonance imaging》2006,24(10):1333-1339
The aims of this study were to investigate the applicability of Fourier fitting in the magnetic resonance (MR) evaluation of left ventricular (LV) function and to determine the optimal number of harmonics for fitting. Cine cardiac MR imaging was performed in 10 subjects, and an LV time–volume curve was generated. Fourier fitting was applied to the original curve using 1–10 harmonics, and the qualities of the time–volume curve and first-derivative curve were evaluated. LV functional parameters were calculated from curves generated with and without fitting. The quality of the original time–volume curve was good, and Fourier fitting had no substantial effect on functional parameters obtained directly from the time–volume curve such as ejection fraction. The first-derivative curve generated without fitting showed substantial artificial fluctuation. The application of Fourier fitting depressed the fluctuation and tended to decrease estimates of peak ejection rate and peak filling rate. Five or six harmonics appeared to be appropriate for obtaining a high-quality first-derivative curve. In conclusion, Fourier fitting was indicated to aid in reducing the artificial fluctuation of the first-derivative curve generated from cine cardiac MR imaging and to contribute to the evaluation of functional parameters derived from the first-derivative curve. 相似文献
42.
Yamamoto M Nakaoka S Ura Y Kataoka Y 《Chemical communications (Cambridge, England)》2012,48(8):1165-1167
A palladium-catalyzed reaction of vinylarenes, allyl ethers, and 1,5-dienes with pinacol proceeded via a selective anti-Markovnikov nucleophilic attack to afford corresponding terminal acetals as major products. The bulkiness of pinacol was found to be critical in controlling the regioselectivity. 相似文献
43.
Yamaguchi T Watanabe S Matsumura Y Tokuoka Y Yokoyama A 《Chemical & pharmaceutical bulletin》2012,60(4):508-512
Vanadium complexes with different ligands were synthesized and evaluated for antiproliferative activity on U937 cells. The alkyl chain length of the ligands affected the antiproliferative activity, and two complexes-3b and 4-exhibited strong activities with IC(50) values of 6.02 and 3.90 μM respectively. Annexin V staining and DNA ladder formation indicated that these complexes induced apoptosis in U937 cells. 相似文献
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46.
The performance test of a shell-and-plate type evaporator (total surface area 21.95 m2, length 1450 mm, width 235 mm, 100 plates) for ocean thermal energy conversion (OTEC) plants is reported. Freon 22 (R22) and ammonia (NH3) were used as the working fluid. Empirical correlations are proposed for predicting the boiling heat transfer and the heat transfer coefficients on the water side. The water-side pressure drop is about 2.9 × 104 N/m2 when the warm water velocity is 0.7 m/s. The water-side friction factor is obtained. 相似文献
47.
The ring opening of N-tosylaziridines with trimethylsilylated nucleophiles, catalyzed by N,N,N',N'-tetramethylethylenediamine, led to the production of beta-functionalized sulfonamides in good to excellent yields with high regioselectivity. [reaction: see text] 相似文献
48.
We investigated the capillary electrophoretic behavior of single-stranded DNA fragments in methylcellulose solution, and found that triplet-repeat DNA showed anomalously faster mobilities than DNA markers with random sequence. Through the further study on the electrophoretic data, reptation model is proven appropriate to describe the migration of DNA under our experimental conditions. Accordingly, with the equations based on reptation theory, we could obtain the persistence length of DNA fragments and find that these values of triplet-repeat DNAs are larger than that of DNA markers with random sequence, which means the former DNAs are less flexible than the latter ones when they migrate in the electric field. This phenomenon is supposed to result from the characteristic higher-order structure formed by GC base pairs within triplet-repeat DNA, which is further proven by the resumed migration order in accordance with DNA size when the denaturant is added into the sieving matrix. 相似文献
49.
Ab initio multireference and coupled cluster methods (MR-SDCI(+Q), CASPT2, CCSD(T)) and density functional theory methods (B3LYP, MPWPW91) have been applied to examine geometrical structures and vibrational frequencies of noble gas (Ng) – transition metal compounds, Ng–NiCO, Ng–NiN2, and Ng–CoCO (Ng = He, Ne, Ar, Kr, Xe). It is shown that the respective compounds can have a larger binding energy than a typical van der Waals interaction energy. The binding mechanism is explained by a partial electron transfer from a noble gas atom to the low-lying 4s and 3d vacant orbitals of the transition metal atom. Theoretical calculations show that the binding of noble gas atom results in a large shift of the bending frequency: 361.1cm–1 (NiCO) to 403.5cm–1 (Ar–NiCO); 308.5cm–1 (NiN2) to 354.8cm–1 (Ar–NiN2); 373.0cm–1 (CoCO) to 422.6cm–1 (Ar–CoCO). The corresponding experimental frequencies determined in solid argon are 409.1cm–1 (NiCO), 357.0cm–1 (NiN2), and 424.9cm–1 (CoCO), which are much closer to the corresponding frequency of Ar–NiCO, Ar–NiN2, and Ar–CoCO, respectively. 相似文献
50.
Yuriko Akiyama 《Journal of fluorine chemistry》2006,127(7):920-923
Ring-opening fluorination reactions of epoxides using tetrabutylammonium bifluoride (TBABF)-KHF2, or Et3N-3HF under microwave irradiation were applied for the introduction of a fluorine atom into the carbohydrate molecules. When TBABF-KHF2 was used as the fluorination reagent, a fluorine atom was introduced regioselectively and various functional groups can tolerate the conditions. When Et3N-3HF was used under microwave irradiation, the reaction time could be remarkably shortened compared with the conventional oil-bath heating. 相似文献