The protonation of the spermine containing calf thymus DNA (molecular mass 15 and 5 MDa) solutions has been studied by means of circular dichroism method. It has been shown that the acid-induced transition from the low-protonated B(+)-form to the double-stranded structure with presumably Hoogsteen complementation of syn-G.C-base-pairs (S-form) in case of high-molecular partially condensed DNA is accompanied by differential scattering of circularly polarized light (DSCPL). The comparative study of protonation of partially and completely condensed low-molecular DNA enabled to obtain a family of DSCPL spectra. It has been demonstrated that the B+----S-transition in partially condensed high-molecular DNA is associated with formation of large intermolecular aggregates (with dimensions about 200 divided by 400 nm) which are destructed by acid-induced DNA denaturation.
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Nat Commun
January 2025
Department of Physics and London Centre for Nanotechnology, King's College London, London, WS2R 2LS, UK.
Controlling scattering and routing of chiral light at the nanoscale is important for optical information processing and imaging, quantum technologies as well as optical manipulation. Here, we introduce a concept of rotating chiral dipoles in order to achieve unidirectional chiral scattering. Implementing this concept by engineering multipole excitations in helicoidal plasmonic nanoparticles, we experimentally demonstrate enantio-sensitive and highly-directional forward scattering of circularly polarised light.
View Article and Find Full Text PDFUsing the first principle calculations, we propose a boron and nitrogen cluster incorporated graphene system for efficient valley polarization. The broken spatial inversion symmetry results in high Berry curvature at and valleys of the hexagonal Brillouin zone in this semiconducting system. The consideration of excitonic quasiparticles within the approximation along with their scattering processes using the many-body Bethe-Salpeter equation gives rise to an optical gap of 1.
View Article and Find Full Text PDFACS Nano
January 2025
Jiangsu Key Laboratory of Frontier Material Physics and Devices, School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006, China.
Circular differential scattering (CDS) spectroscopy has been developed as a powerful method for the characterization of the optical activity of individual plasmonic nanostructures and their complexes with chiral molecules. However, standard measurement setups often result in artifacts that have long raised concerns on the interpretation of spectral data. In fact, the detection limit of CDS setups is constrained by the high level of artifacts, to ±10%.
View Article and Find Full Text PDFNanophotonics
November 2024
College of Electronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China.
Flexible and diverse manipulation of electromagnetic (EM) waves in half space (reflection or transmission) has facilitated strong aspiration toward full-space wave control. However, it remains challenging to achieve independent amplitude and phase control, which seriously hinder the real-world applications. Herein, an innovative strategy of trifunctional metasurface is proposed to independently and simultaneously manipulate the amplitude and phase of circular polarized waves in full space.
View Article and Find Full Text PDFNanophotonics
August 2024
School of Electronic Engineering, Xidian University, Xi'an, 710071, China.
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