Tiopronin (TP) is a synthetic thiol compound without chromophore. By optimizing the chromatographic conditions and sample preparation processes, an improved LC-MS/MS analytical method without derivatization has been developed and validated to determine TP concentrations in human plasma. After reduction with 1,4-dithiothreitol, plasma samples were deproteinized with 10% perchloric acid. The post-treatment samples were analyzed on a C₈ column interfaced with a triple quadrupole tandem mass spectrometer in negative electrospray ionization mode. Methanol-5 mmol/L ammonium acetate (20:80, v/v) was used as the isocratic mobile phase. The assay was linear over the concentration range of 40.0-5000 ng/mL. The intra- and inter-day precisions were within 12.9% in terms of relative standard deviation and the accuracy within 5.6% in terms of relative error. This simple and sensitive LC-MS/MS method with short analytical time (3.5 min each sample) was successfully applied to the pharmacokinetic study of TP in healthy Chinese male volunteers after an oral dose of 300 mg TP.
Fast radio bursts (FRBs) are radio transients of short duration and bright, with their physical mechanism not being fully understood. We conducted the targeted search for bursts from FRB 20201124A between June 2 and July 20, 2021. High time-resolution data were collected for 104.5 hr using the ROACH2-based digital backend. We introduce the details of our FRB search pipeline which is based on HEIMDALL and FETCH. Testing of the injected mock FRBs search could help us better understand the performance of the pipelines, and improve the search algorithms and classifiers. To study the efficiency of our pipeline, 5000 mock FRBs were injected into the data and searched using the pipeline. The results of the mock FRBs search show that our pipeline can recover almost all (≳ 90 %) the injected mock FRBs above signal-to-noise ratio (SNR) threshold of 15, and is still acceptable (≳ 80 %) for injected SNRs from 10 to 15. The recovery fraction displays relations with SNR, dispersion measure (DM), and pulse width. No bursts were detected from FRB 20201124A in the middle of 2021. The non-detection of FRB 20201124A may be due to its quiet phase window or no emission above the threshold of Nanshan telescope.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.