A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method as an alternative to a gas chromatography-thermal energy analyser (GC-TEA) method recommended by the European Committee on Standardization (CEN) was validated for the simultaneous determination of eight N-nitrosamines released into artificial saliva from rubber or elastomer teats and soothers. N-nitroso-dipropylamine-d₁₄ (NDPA-d₁₄) was used as internal standard for accurate quantification. The method was validated with relatively good analytical results, including sufficiently low limits of detection (0.1-2 µg kg⁻¹) of sample) and good linearity (r²> 0.99) throughout the studied concentration ranges. Intra- and inter-day precisions expressed with the relative standard deviation (RSD, %) were 3.4-8.0% and 4.4-11.3%, which were below the performance criteria based on one-half of the value derived from the Horwitz value. It was also found that the LC-MS/MS method is sufficiently rugged and successfully applicable to its routine analysis for the compliance test of Commission Directive 93/11/EEC.
Aims: To clone and overexpress a novel levan fructotransferase gene lftA from Arthrobacter ureafaciens K2032. Methods and Results: The lftA gene, encoding a levan fructotransferase (LFTase) of 521 amino acids (aa) residues, was cloned from the genomic DNA of A. ureafaciens K2032, and overexpressed in Escherichia coli. The recombinant LFTase overexpressed in E. coli was then used to produce a difructose dianhydride (DFA IV) from levan. DFA IV crystals with 97% purity could be obtained from the reaction mixture in 83AE7% yield by using a natural crystallization method. Conclusions: The lftA gene cloned from A. ureafaciens K2032 encode a novel levan fructotransferase which produces difructose dianhydride (DFA IV) from levan. Significance and Impact of the Study: Levan fructotransferase is a useful enzyme with great promise in the production of DFA IV and various fructosides.
The Asia-Pacific Economic Cooperation (APEC) Harmonization Center (AHC) was established in 2009 with the purpose of promoting harmonization of regulatory processes for drugs and medical devices. The AHC held three training workshops on multiregional clinical trials (MRCTs); these workshops provided forums for discussing the value and potential benefits of MRCTs. Participants from regulatory agencies, the pharmaceutical industry, and academia identified many issues and made recommendations for resolving major challenges with the aim of improving the capacity of the Asia-Pacific region to carry out MRCTs.
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