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Circular dichroism spectroscopy is frequently used to characterize the chiral biomolecules by measuring the absorption spectra contrast between the left-handed circularly polarized light and the right-handed circularly polarized light. Compared with biomolecules, chiral metal plasmonic nanostructures also produce a strong circular dichroism response in the range of near-infrared. However, due to the large damping rate, the non-adjustable resonant frequency of the conventional metals, the applications of chiral metal plasmonic nanostructures in the fields of photoelectric detection and chemical and biochemical sensing are restricted. Here, we present a chiral graphene plasmonic Archimedes' spiral nanostructure that displays a significant circular dichroism response under the excitation of two polarizations of circularly polarized light. By manipulating the material and geometric parameters of the Archimedes' spiral, the stronger circular dichroism responses and modulation of the resonant wavelength are achieved. The optimized plasmonic nanostructure has outstanding refractive index sensing performance, where the sensitivity and figure of merit reach 7000nm/RIU and 68.75, respectively. Our proposed chiral graphene plasmonic Archimedes' spiral nanostructure might find potential applications in the fields of optical detection and high performance of index sensing.
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http://dx.doi.org/10.1364/OE.403041 | DOI Listing |
Curr Res Food Sci
August 2025
Department of Molecular Food Chemistry and Food Development, Institute of Food and One Health, Leibniz University Hannover, Am Kleinen Felde 30, 30167, Hannover, Germany.
A- and B-type procyanidins (PCs) are widely known for their health-promoting properties, such as antioxidant activity. The limited availability of reference substances represents a major challenge, resulting in a low number of systematic studies on their health benefits. In our study, the optimised 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-induced oxidation of the B-types B1 and B2 was carried out yielding the corresponding A-types A1 (1) and A2 (2), which have an additional ether bridge between C2--C7, whereas oxidation of B3 and B4 produced a six-membered spirocyclic ring system including a spiro-carbon atom at C8t (3-5).
View Article and Find Full Text PDFRiceglutelin (RG)-rhamnolipids (Rha)-high-methoxyl pectin (HMP)/medium-methoxy pectin (MMP)/low-methoxy pectin (LMP) were used to attract self-assembled nanoparticles by electrostatic attraction, and the effects of pectin esterification degree and concentration on the characteristics of nanoparticles and the bioavailability of curcumin were evaluated. The minimum particle size and the highest encapsulation efficiency of the nanoparticles were at mass ratios of RG:HMP = 2:1, RG:MMP = 4:1, and RG:LMP = 2:1. The results of Fourier transform infrared spectroscopy and circular dichroism spectroscopy show that hydrogen bonding, hydrophobic interaction, and electrostatic attraction are the main driving forces for the formation of complexes.
View Article and Find Full Text PDFMol Ther Nucleic Acids
September 2025
Department of Chemistry, University of Massachusetts, Lowell, MA 01854, USA.
We combined circular dichroism (CD) and viscosity measurements with molecular dynamics (MD) simulations and classification and regression approaches to machine learning to characterize solution structures of 22-mer, 25-mer, and 30-mer peptide- (-GlyArg6) conjugated phosphorodiamidate morpholino oligonucleotides (PPMOs). PPMO molecules form non-canonical folded structures with 1.4- to 1.
View Article and Find Full Text PDFSci Technol Adv Mater
August 2025
Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan.
Emergent ferromagnetism on the surface of two-dimensional (2D) MXene is investigated by X-ray magnetic circular dichroism (XMCD) and angle-dependent hard X-ray photoemission spectroscopy (HAXPES). Focusing on CrN as one of the 2D-MXenes, high quality bilayers of CrN/Co and CrN/Pt are prepared by a magnetron sputtering technique. XMCD reveals the induced magnetic moment of Cr in the CrN/Co interface, while it is not observed in the CrN/Pt interface at room temperature.
View Article and Find Full Text PDFPhytochemistry
September 2025
State Key Laboratory of Discovery and Utilization of Functional Components in Traditional Chinese Medicine, Guizhou Medical University, Natural Products Research Center of Guizhou Province, Guiyang 550014, China. Electronic address:
Seven previously undescribed glycosides, including four iridoid glycosides (1, 2, 4, and 5), three phenolic glucosides (18, 21, and 22), together with nineteen known compounds, were isolated from the ethanol extract of Gentiana rhodantha Franch. Their structures were determined by analysis of 1D and 2D NMR, HRESIMS, X-ray diffraction, NMR calculation, and electronic circular dichroism (ECD) calculation. Among them, compound 21 was a novel highly rearranged endo-phenolic analogue with a unique skeleton.
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