Electron paramagnetic resonance (EPR) spectroscopy detects the presence of radicals of biological interest, such as ascorbyl radical (A(•)) and lipid radicals. A(•) is easily detectable by EPR even in aqueous solution at room-temperature. Under oxidative conditions leading to changes in total ascorbate (AH(-)) content, the A(•)/AH(-) ratio could be used to estimate early oxidative stress in the hydrophilic milieu. This methodology was applied to a wide range of aquatic systems including algae, sea urchin, limpets, bivalves and fish, under physiological and oxidative stress conditions as well. The A(•)/AH(-) ratio reflected the state of one part of the oxidative defense system and provided an early and simple diagnosis of environmental stressing conditions. Oxidative damage to lipids was assessed by the EPR-sensitive adduct formation that correlates well with cell membrane damage with no interference from other biological compounds. Probe instability, tissue metabolism, and lack of spin specificity are drawback factors for employing EPR for in vivo determination of free radicals. However, the dependability of this technique, mostly by combining it with other biochemical strategies, enhances the value of these procedures as contributors to the knowledge of oxidative condition in aquatic organisms.
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http://dx.doi.org/10.1016/j.cbpa.2013.02.021 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States.
The development of molecular species with switchable magnetic properties has been a long-standing challenge in chemistry. One approach involves binding an analyte, such as protons, to a compound to trigger a change in magnetism. Transition metal complexes have been targeted for this type of magnetic modulation because they can undergo changes in their spin states.
View Article and Find Full Text PDFJ Neurol
January 2025
Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Background: In multiple sclerosis (MS), susceptibility-weighted imaging (SWI) may reveal white matter lesions (WML) with a paramagnetic rim ("paramagnetic rim lesions" [PRLs]) or diffuse hypointensity ("core-sign lesions"), reflecting different stages of WML evolution.
Objective: Using the soma and neurite density imaging (SANDI) model on diffusion-weighted magnetic resonance imaging (MRI), we characterized microstructural abnormalities of MS PRLs and core-sign lesions and their clinical relevance.
Methods: Forty MS patients and 20 healthy controls (HC) underwent a 3 T brain MRI.
Inorg Chem
January 2025
Henan Key Laboratory of Polyoxometalate Chemistry, College of Chemistry and Molecular Sciences, Henan University, Kaifeng, Henan 475004, P. R. China.
Developing new photocatalysts for the selective oxidation of thioethers to high-value-added sulfoxides under low-oxygen mild conditions is a promising but challenging strategy. Here, a new polyoxometalate-based metal-organic framework (POMOF), , was successfully synthesized, wherein continuous π···π stacking interactions and direct coordination bonds not only strengthen the framework's stability but also accelerate electron transfer. A series of experiments and theoretical studies, including control experiments, kinetic studies, electrochemical spectroscopic analyses, and electron paramagnetic resonance, revealed the synergistic catalytic effect among Co(II) metal centers, BWO, and the photosensitizer TPT.
View Article and Find Full Text PDFNanoscale
January 2025
School of Chemistry & Chemical Engineering, School of Materials Science and Engineering and Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Department of Chemistry and Center for Atomic Engineering of Materials, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of the Ministry of Education, Anhui University, Hefei, 230601, China.
Atomically precise nanoclusters (NCs) can serve as an excellent platform for a comprehensive understanding of structure-property relationships. Herein, three structurally similar Cu NCs (Cu-1, Cu-2 and Cu-3) have been prepared for the photocatalytic phenylacetylene self-coupling reaction. It was found that Cu-1 NC achieved the highest turnover number (TON) of 524.
View Article and Find Full Text PDFJ Radiat Res
January 2025
International Agency for Research on Cancer, Environment and Lifestyle Epidemiology Branch, Av. Tony Garnier, Lyon 69007, France.
Between 1949 and 1962 the Soviet Union performed atmospheric tests of nuclear weapons at the Semipalatinsk nuclear test site (SNTS) in Kazakhstan, resulting in widespread contamination of the surrounding region with radioactive fallout. Settlements in the southeast Abai oblast of Kazakhstan, close to the border with China, are not thought to have received significant fallout from the SNTS. There is, however, evidence that the study area, including Makanchi, Urdzhar and Taskesken villages, was contaminated by atmospheric nuclear tests performed by China at the Lop Nor NTS between 1964 and 1980.
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