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121.
The low-lying levels in74As have been studied by means ofγ-ray and internal conversion electron spectroscopy following the74Ge(p,n)74As reaction. New levels at 372.7, 532.8, 632.1, 731.6, 752.7, 758.3, 801.6, 902.9 and 1128.5 keV, not observed in earlier
studies, have been established.J
π assignments have been made to several low-lying levels. An earlier ambiguity regarding the identification of an isomeric
level has been clarified. The half-life of a level at 271.4 keV has been measured to be 1.0±0.1 nsec; in addition, limits
on half-lives of levels at 182.7, 277.5 and 425.4 keV have been assigned. The level structure is discussed on the basis of
available nuclear models. 相似文献
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124.
Venkata Naresh Vema Y. Bharathi kumari Sridhar Musulla RamaKrishnam Raju Addada Srinivasa Rao Alapati 《Tetrahedron letters》2018,59(47):4165-4167
Greensporone C, a new 14-membered resorcylic acid lactone, has been synthesized from inexpensive and commercially available starting materials. This convergent synthesis utilizes Cross metathesis using the Grubbs Hoveyda catalyst, alkylation of 1,3-dithiane and Yamaguchi macrolactonization as key steps. 相似文献
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127.
Black cohosh (Actaea recemosa) is a popular botanical used for women’s health. The rhizomes/roots used in black cohosh products are often collected from the wild; a correct identification is therefore crucial. An HPLC-ELSD method has been developed for the analysis of terpenoids in different Actaea species samples. The best results were obtained with a Phenomenex Discovery column using gradient mobile phase of water (0.1% acetic acid), acetonitrile (0.1% acetic acid) and reagent alcohol. Owing to their low UV absorption, the triterpene saponins were detected by evaporative light scattering. Elution was run at a flow rate of 1.0 mL min?1. This paper discusses the use of the chemical fingerprinting technique as a means of identifying A. recemosa from three closely related species, A. pachypoda, A. podocarpa and A. rubra, respectively. This method suggests that the analytical method could be a useful method for quality control and identifying species. 相似文献
128.
Synergistic extraction of trivalent rare earths from nitrate solutions using mixtures of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301=HX) and trialkyl phosphine oxide (Cyanex 923=TRPO) in xylene has been investigated. The results demonstrate that these trivalent metal ions are extracted into xylene as MX(3).3HX with Cyanex 301 alone. In the presence of Cyanex 923, La(III) and Nd(III) are found to be extracted as MX(2).NO(3).TRPO. On the other hand, Eu(III), Y(III) and heavier rare earths are found to be extracted as MX(3).HX.2TRPO. The addition of a trialkylphosphine oxide to the metal extraction system not only enhances the extraction efficiency of these metal ions but also improves the selectivities significantly, especially between yttrium and heavier lanthanides. The separation factors between these metal ions were calculated and compared with that of commercially important extraction systems like di-2-ethylhexyl phosphoric acid. 相似文献
129.
Vijaya D. Bharathi Kanbarpa Radharani Banda Jagadeesh Gajjela Ramulu Indu Bhushan Andra Naidu Ramesh Mullangi 《Chromatographia》2008,67(5-6):461-466
A rapid, sensitive, and simple HPLC–MS–MS method, with electro-spray ionization and cetirizine as internal standard (IS),
has been developed and validated for simultaneous quantification of fexofenadine and pseudoephedrine in human plasma. The
analytes were isolated from plasma by solid-phase extraction (SPE) on Oasis HLB cartridges. The compounds were chromatographed
on an RP 18 column with a mixture of ammonium acetate (10 mm, pH 6.4) and methanol as mobile phase. Quantification of the analytes was based on multiple reaction monitoring (MRM) of
precursor-to-product ion pairs m/z 502 → 466 for fexofenadine, m/z 166 → 148 for pseudoephedrine, and m/z 389 → 201 for cetirizine. The linear calibration range for both analytes was 2–1,700 ng mL−1 (r = 0.995), based on analysis of 0.1 mL plasma. Extraction recovery was 91.5 and 80.88% for fexofenadine and pseudoephedrine,
respectively. The method was suitable for analysis of human plasma samples obtained 72 h after administration of a drug containing
both fexofenadine and pseudoephedrine. 相似文献
130.
A new route to C2-symmetric diamines via an asymmetric reductive dimerization of 1-acylpyridinium salts and their benzo derivatives is described. This method is practical as the starting heterocycles and chiral auxiliaries are readily available. The titanium reducing agent is inexpensive and easy to prepare. Several novel enantiopure C2-symmetric diamine derivatives were synthesized using this method. 相似文献