Direct and indirect reversed-phase (RP) high-performance liquid chromatographic methods were developed for the separation of enantiomers of 18 unnatural beta-amino acids, including several beta-3-homo amino acids. The direct separations of the underivatized analytes were performed on chiral stationary phases (CSPs) containing macrocyclic glycopeptide antibiotic teicoplanin (Chirobiotic T column) and teicoplanin aglycone (Chirobiotic TAG column). The indirect method involved pre-column derivatization with a new chiral derivatizing agent (CDA), (S)-N-(4-nitrophenoxycarbonyl)phenylalanine methoxyethyl ester ((S)-NIFE), and subsequent separation of diastereomers on Discovery C18 and Hyperpep 300 C18 columns. The different methods were compared in systematic chromatographic examinations. The effects of organic modifier, mobile phase composition, pH and flow rate on the separation were investigated.
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http://dx.doi.org/10.1016/j.chroma.2003.08.070 | DOI Listing |
Nanophotonics
January 2025
Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
Topological insulators and bound states in the continuum represent two fascinating topics in the optical and photonic domain. The exploration of their interconnection and potential applications has emerged as a current research focus. Here, we investigated non-Hermitian photonics based on a parallel cascaded-resonator system, where both direct and indirect coupling between adjacent resonators can be independently manipulated.
View Article and Find Full Text PDFPeerJ
January 2025
Department of Environmental Engineering, Konkuk University, Seoul, Republic of Korea.
Approximately 64% of the Republic of Korea comprises mountainous areas, which as cold and high-altitude regions are gravely affected by climate change. Within the mountainous and the alpine-subalpine ecosystems, microbial communities play a pivotal role in biogeochemical cycling and partly regulate climate change through such cycles. We investigated the composition and function of microbial communities, with a focus on fungal communities, in Republic of Korea's second tallest mountain, Mt.
View Article and Find Full Text PDFFront Nutr
January 2025
Shanghai-MOST Key Laboratory of Health and Disease Genomics, NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Shanghai, China.
Taste preference drives food selection, acceptance, or rejection and influences nutritional status and body mass index. Nevertheless, there are few reports concerning pregnant women. Mala flavor, characterized by its "numbing" and "spicy" sensations, is a distinctive taste of Sichuan cuisine, created by the combination of Chinese prickly ash and chili peppers.
View Article and Find Full Text PDFBr J Health Psychol
February 2025
Division of Gerontology, Geriatrics, and Palliative Care, University of Alabama at Birmingham School of Medicine and Birmingham VA Medical Center, Birmingham, Alabama, USA.
Objective: Mechanistic studies are needed to understand why depressive symptoms are associated with poorer physical health. The objective of this study was to examine whether behavioural, cognitive and physiological factors mediated an association between depressive symptoms, measured in early adulthood, and lower urinary tract symptoms (LUTS) and their impact, a composite variable measured in mid-life adulthood, among women in the Coronary Artery Risk Development in Young Adults study, conducted in four regions of the United States.
Design: Prospective cohort study.
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