Naringin is the natural chief bitter flavonoid found in Citrus species. Herein, bitter naringin was treated with atmospheric pressure plasma to afford two new converted flavonoids, narinplasmins A (2) and B (3), along with the known compound, 2R-naringin. The structures of the two new naringin derivatives were elucidated on the basis of spectroscopic methods. The antioxidant activity of all isolates was evaluated based on 1,1-diphenyl-2-picrylhydrazyl and peroxynitrite (ONOO(-)) scavenging assays. The new flavanone glycoside 2 containing a methoxyalkyl group exhibited significantly improved antioxidant properties in these assays relative to the parent naringin.
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http://dx.doi.org/10.1016/j.bmcl.2015.01.054 | DOI Listing |
JACS Au
December 2024
Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
A critical reaction affecting the oxidation chemistry in the middle-to-upper atmosphere occurs between hydroxyl (OH) and hydroperoxyl (HO). The reaction rate coefficient for OH + HO → HO + O, here called , has challenged laboratory kineticists for 50 years. However, several measurements from the past 30 years had approached a rough consensus until the publication of a new study that examined, for the first time, the water vapor dependence of this reaction.
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December 2024
Space Research Institute, Austrian Academy of Sciences, Schmiedlstraße 6, Graz, 8042 Austria.
Plasma flows with enhanced dynamic pressure, known as magnetosheath jets, are often found downstream of collisionless shocks. As they propagate through the magnetosheath, they interact with the surrounding plasma, shaping its properties, and potentially becoming geoeffective upon reaching the magnetopause. In recent years (since 2016), new research has produced vital results that have significantly enhanced our understanding on many aspects of jets.
View Article and Find Full Text PDFSci Rep
December 2024
School of Geophysics and Measurement-control Technology, East China University of Technology, Nanchang, People's Republic of China.
In this study, long-term and continuous monitoring of atmospheric radon concentration, temperature, air pressure, and humidity was conducted at China Jinping Underground Laboratory. The impacts of temperature, humidity, and air pressure on radon concentration in the experimental environment were specifically examined, along with the potential interactions among these factors. Moreover, Radon data were denoised using Singular Spectrum Analysis (SSA) to reveal factors that might influence changes in radon concentration.
View Article and Find Full Text PDFFood Chem
December 2024
Dipartimento di Chimica; Centro Interdipartimentale SMART.
Plant metabolites known as cucurbitacins are known to impart an unpleasant bitter taste to edible fruits and even lead to severe health complications after the ingestion of relatively high amounts. In this study, an analytical method based on reversed phase liquid chromatography with combined detection by UV spectroscopy and atmospheric pressure chemical ionization high-resolution single/tandem mass spectrometry was applied to confirm the occurrence of four cucurbitacins (B, D, and R, and 23,24-dihydro cucurbitacin B) previously inferred in unexpectedly bitter-tasting fruits of an Italian variety (Scopatizzo) of unripe melon (Cucumis melo L.), known for the sweetness of its fruits.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan.
The surface of the eye is constantly exposed to the external environment and is affected by atmospheric conditions and air pollution, and dry eye is a typical ocular surface disease. The aim of this study is to determine whether there are seasonal differences in the number of dry eye operations in Japan and to investigate whether meteorological conditions and air pollutants are related to. The operations were examined using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) database from fiscal years 2019 to 2021.
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