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91.
Summary Strontium showed a high atomic emission in a molybdenum microtube. The addition of hydrogen in the argon gas atmosphere served to increase the atomic emission. No interferences from less than 5 ng of potassium, calcium and magnesium were found. Other elements also had no interferences at the concentration levels usually found in biological samples. Samples were digested with nitric acid in a Uni-Seal decomposition vessel. The results obtained showed good agreement with the certified values. Atomic emission spectrometry with a molybdenum microtube atomizer permits a simple and sensitive determination of strontium in biological samples (coefficient of variation 2.5% for 10 pg Sr).
This work was supported by the Ministry of Education, Science and Culture of Japan through a Grant-in-Aid for Special Project Research. 相似文献
Strontiumbestimmung in biologischem Material durch Atomemissions-Spektrometrie mit elektrothermischer Atomisierung
Zusammenfassung Eine hohe Atomemission wurde für Strontium bei Verwendung einer Molybdän-Mikroröhre beobachtet. Durch Wasserstoffzusatz zum Argon konnte sie noch weiter erhöht werden. Weniger als 5 ng K, Ca und Mg verursachen keine Störung. Andere Elemente stören nicht in den Konzentrationsbereichen, wie sie üblicherweise in biologischen Materialien vorkommen. Der Aufschluß der Proben wurde mit Salpetersäure in Uni-Seal-Gefäßen vorgenommen. Die erhaltenen Werte stimmten gut mit zertifizierten Daten überein. Die vorgeschlagene Methode ermöglicht eine einfache und empfindliche Strontiumbestimmung in biologischen Proben (Variationskoeffizient 2,5% bei 10 pg Sr).
This work was supported by the Ministry of Education, Science and Culture of Japan through a Grant-in-Aid for Special Project Research. 相似文献
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94.
Numata M Koumoto K Mizu M Sakurai K Shinkai S 《Organic & biomolecular chemistry》2005,3(12):2255-2261
We already found that beta-1,3-glucan polysaccharides form polymeric complexes with certain polynucleotides, but the parallel vs. anti-parallel orientation in those complexes had remained unsolved. In this paper, this controversial problem has been discussed for curdlan/oligo(dA) complexes utilizing two different energy transfer techniques. The first system consists of a combination of fluorescein-labeled curdlan and 3'-(or 5'-)tetramethyl-rhodamine (TAMRA)-labeled oligo(dA). The second system utilizes gold nanoparticles: that is, two curdlan chains were linked by a disulfide bond and after complexation with oligo(dA), the complex was immobilized on gold nanoparticles. In this system, TAMRA was attached to the 3'(or 5') end of oligo(dA) and the gold particle acted as a fluorescence quencher (energy acceptor). These experiments have led us to conclude that in the curdlan/oligo(dA) complex, parallel orientation is more favourable than anti-parallel orientation. These findings have enabled us to envision a clearer image for the complexation mode between beta-1,3-glucan polysaccharides and polynucleotides. 相似文献
95.
Kuriyama M Soeta T Hao X Chen Q Tomioka K 《Journal of the American Chemical Society》2004,126(26):8128-8129
A catalytic asymmetric arylation of sterically tuned imines with arylboroxines was developed by using N-Boc-l-valine-connected amidomonophosphane rhodium(I) catalyst in n-PrOH. The TMS group used for the steric tuning of imines is convertible to other functionalities that are applicable as a key foothold for the carbon-carbon bond-forming coupling reactions. 相似文献
96.
T. Sato A. Narazaki Y. Kawaguchi H. Niino 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1477-1479
Laser irradiation of solid nitrogen containing cyanuric triazide (C3N12) could generate highly reactive carbon nitride species, NCN and dicyanocarbodiimide. These species were generated in the solid nitrogen at 20 K. After laser photolysis, generated reactive species were concentrated by removal of nitrogen, and converted into a film-like product. Thus, the obtained product was characterized by means of FTIR, SEM, and XPS measurements. The product was assigned to amorphous carbon nitride with relatively high nitrogen content (N/C=0.91.3). PACS 81.15.Fg; 82.33.-z; 68.55.Nq 相似文献
97.
Itaka K Kanayama N Nishiyama N Jang WD Yamasaki Y Nakamura K Kawaguchi H Kataoka K 《Journal of the American Chemical Society》2004,126(42):13612-13613
An siRNA nanocarrier formed through self-assembly of PEG-based block catiomer possessing two distinct amino groups with different pKa values in a side chain was developed. This design provided the carrier with a sufficient siRNA complexation and an assumed buffering capacity in the endosomes, allowing it to exhibit remarkable gene knockdown abilities as well as sufficient serum tolerability. 相似文献
98.
Fujimoto H Nakamura E Okuyama E Ishibashi M 《Chemical & pharmaceutical bulletin》2004,52(8):1005-1008
In a screening study on immunomodulatory fungal metabolites, three known anthraquinones, carviolin (roseo-purpurin) (1), 1-O-methylemodin (2), omega-hydroxyemodin (citreorosein) (4), and a new anthraquinone, omega-acetylcarviolin (3), together with a known steroid, ergosta-4,6,8(14),22-tetraen-3-one (5) and a new steroid, 25-hydroxyergosta-4,6,8(14),22-tetraen-3-one (6) were isolated from an Ascomycete, Zopfiella longicaudata, and found to have moderate immunosuppressive activities. The structure-activity relationships of these metabolites are discussed. 相似文献
99.
Ikeda S Sanuki R Miyachi H Miyashita H Taniguchi M Odashima K 《Journal of the American Chemical Society》2004,126(33):10331-10338
A Ni(0)/ZnCl(2) system effectively promotes the coupling of enones and alkene-tethered alkynes. In the reaction with 1,6-enynes, the oxidative cyclization of Ni(0) species on enones across the alkyne part followed by ZnCl(2)-promoted cleavage generates alkenylnickel intermediates. Subsequent migratory insertion of the tethered alkene occurs with 5-exo-cyclization. When the resulting sigma-alkylnickel intermediates have beta-hydrogen atoms, the reaction terminates by beta-hydrogen elimination to provide cyclopentane derivatives. On the other hand, a sigma-alkylnickel intermediate that does not have beta-hydrogen atoms undergoes the insertion of a second alkene unit to cause a domino effect via a three-fold C-C bond formation process with and without the cleavage of one C-C bond. 相似文献
100.
Eguchi K Enomoto S Furuno K Goldman J Hanada H Ikeda H Ikeda K Inoue K Ishihara K Itoh W Iwamoto T Kawaguchi T Kawashima T Kinoshita H Kishimoto Y Koga M Koseki Y Maeda T Mitsui T Motoki M Nakajima K Nakajima M Nakajima T Ogawa H Owada K Sakabe T Shimizu I Shirai J Suekane F Suzuki A Tada K Tajima O Takayama T Tamae K Watanabe H Busenitz J Djurcic Z McKinny K Mei DM Piepke A Yakushev E Berger BE Chan YD Decowski MP Dwyer DA Freedman SJ Fu Y Fujikawa BK Heeger KM Lesko KT Luk KB Murayama H 《Physical review letters》2003,90(2):021802
KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded. 相似文献