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131.
New synthetic methods of tulipalin A were deviced via the retro-Diels-Alder reaction and the generality was demonstrated by the synthesis of several α-methylene-α-alkyl-α-butyrolactones. 相似文献
132.
An improved transient isotachophoresis (tITP) procedure for the preconcentration of iodide from highly saline matrices was developed with the objective to quantify iodide in seawater by capillary electrophoresis (CE). The procedure takes advantage of introducing cetyltrimethylammonium chloride into the high-sodium chloride background electrolyte, which due to a specific interaction with iodide amended placement of the analyte at a large distance from the matrix chloride (the latter performed the role of a leading anion). Computer simulation showed that 2-(N-morpholino)ethanesulfonate could be adopted as a suitable terminating ion to enable isotachophoretic focusing at the beginning of the CE run. Under optimized tITP conditions, the sensitivity response of iodide was improved by a factor of 140 over normal CE mode. This allowed for direct UV detection of as low as 0.6 microg/L iodide and made feasible CE analysis of undiluted surface seawater samples where iodide was found at a 30 microg/L level. The applicability of the proposed tITP-CE method could apparently be extended to the determination of other trace seawater anions (e.g., iodate). 相似文献
133.
Ichihara Mai Inoue Kazumasa Fukushi Masahiro Shimizu Hideo Tsuruoka Hiroshi Veerasamy Nimelan Tsukada Mizuho Soyama Sho Hosokawa Shota Kato Tatsuki Sagara Hiroaki Taguchi Yoshiaki Natarajan Thennaarassan 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(1):427-435
Journal of Radioanalytical and Nuclear Chemistry - Tokatsu area was on one pathway of the radioactive plumes released in the Fukushima Daiichi Nuclear Power Plant accident and absorbed dose rate in... 相似文献
134.
135.
We investigate the long-time behavior of viscosity solutions of Hamilton–Jacobi equations in
\mathbbRn{\mathbb{R}^n} with convex and coercive Hamiltonians and give three general criteria for the convergence of solutions to asymptotic solutions
as time goes to infinity. We apply the criteria to obtain more specific sufficient conditions for the convergence to asymptotic
solutions and then examine them with examples. We take a dynamical approach, based on tools from weak KAM theory such as extremal
curves, Aubry sets and representation formulas for solutions, for these investigations. 相似文献
136.
137.
Murata N Fujimori S Ichihara Y Sato Y Yamaji T Tsuboi H Uchida M Suzuki H Yamada M Oikawa T Nemoto H Nobuhiro J Choshi T Hibino S 《Chemical & pharmaceutical bulletin》2006,54(11):1567-1570
We synthesized 9alpha-fluoromedroxyprogesterone acetate (FMPA) in order to test whether it is a more potent anti-angiogenic agent than medroxyprogesterone acetate (MPA), which has been widely used as a therapeutic agent for breast and endometrium cancers. FMPA was previously synthesized in 10 steps (total yield: 1%). An efficient synthesis of FMPA has been achieved in 6 steps (total yield: 12%). We examined the anti-tumor effect of FMPA, complexed with dimethyl-beta-cyclodextrin (DM-beta-CyD), on rat mammary carcinomas induced by 7,12-dimethylbenz[a]anthracene (DMBA). FMPA showed great anti-tumor effect on DMBA-induced rat mammary carcinomas. 相似文献
138.
Hayakawa S Kitaguchi A Kameoka S Toyoda M Ichihara T 《The Journal of chemical physics》2006,124(22):224320
Doubly charged tungsten hexacarbonyl W(CO)(6) (2+) ions were made to collide with Ar and K targets to give singly and doubly charged positive ions by collision-induced dissociation (CID). The resulting ions were analyzed and detected by using a spherical electrostatic analyzer. Whereas the doubly charged fragment ions resulting from collisional activation (CA) were dominant with the Ar target, singly charged fragment ions resulting from electron transfer were dominant with the K target. The internal energy deposition in collisionally activated dissociation (CAD) evaluated with the Ar target was broad and decreased with increasing internal energy. The predominant peaks observed with the K target were associated with singly charged W(CO)(2) (+) and W(CO)(3) (+) ions: these ions were not the result of CA, but arose from dissociation induced by electron transfer (DIET). The internal energy deposition resulting from the electron transfer was very narrow and centered at a particular energy, 7.8 eV below the energy level of the W(CO)(6) (2+) ion. This narrow internal energy distribution was explained in terms of electron transfer by Landau-Zener potential crossing at a separation of 5.9 x 10(-8) cm between a W(CO)(6) (2+) ion and a K atom, and the coulombic repulsion between singly charged ions in the exit channel. A large cross section of 1.1 x 10(-14) cm(2) was estimated for electron capture of the doubly charged W(CO)(6) (2+) ion from the alkali metal target, whose ionization energy is very low. The term "collision-induced dissociation," taken literally, includes all dissociation processes induced by collision, and therefore encompasses both CAD and DIET processes in the present work. Although the terms CID and CAD have been defined similarly, we would like to propose that they should not be used interchangeably, on the basis that there are differences in the observed ions and in their intensities with Ar and K targets. 相似文献
139.
Wakamatsu Y Matsumoto H Minagawa M Tanioka A 《Journal of colloid and interface science》2006,300(1):442-445
In the present study, the effect of ion-exchange fiber fabric made by electrospray deposition (ESD) on water splitting in a composite bipolar membrane (CBM) was investigated. Cation- and anion-exchange fiber (CEF and AEF) fabrics, which were composed of very thin fibers, were prepared by ESD and postdeposition chemical modification and then used as the intermediate layer of a CBM. The current-voltage characteristics under reverse bias conditions showed that the AEF fabrics enhanced water splitting. The water dissociation is accelerated by the AEF fabric, which contains both tertiary pyridyl groups and quaternary pyridinium groups and has a high specific surface area. On the other hand, the CEF fabric, which contains sulfonic acid groups and has an insufficient specific surface area, reduced water splitting. These results indicate that fiber fabric with catalytic activity and a high surface area obtained by ESD can improve the performance of a CBM. 相似文献
140.
Furuta T Asakawa T Iinuma M Fujii S Tanaka K Kan T 《Chemical communications (Cambridge, England)》2006,(34):3648-3650
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