Surface-enhanced Raman scattering (SERS) nanoprobes have shown tremendous potential in in vivo imaging. The development of single oligomer resolution in the SERS promotes experiments on DNA and protein identification using SERS as a nanobiosensor. As Raman scanners rely on a multiple spectrum acquisition, faster imaging in real-time is required. SERS weak signal requires averaging of the acquired spectra that erases information on conformation and interaction. To build spectral libraries, the simulation of measurement conditions and conformational variations for the nucleotides relative to enhancer nanostructures would be desirable. In the molecular dynamic (MD) model of a sensing system, we simulate vibrational spectra of the cytosine nucleotide in FF2/FF3 potential in the dynamic interaction with the Au20 nanoparticles (NP) (EAM potential). Fourier transfer of the density of states (DOS) was performed to obtain the spectra of bonds in reaction coordinates for nucleotides at a resolution of 20 to 40 cm. The Au was optimized by ab initio density functional theory with generalized gradient approximation (DFT GGA) and relaxed by MD. The optimal localization of nucleotide vs. NP was defined and the spectral modes of both components vs. interaction studied. Bond-dependent spectral maps of nucleotide and NP have shown response to interaction. The marker frequencies of the Au-nucleotide interaction have been evaluated.
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http://dx.doi.org/10.3390/bios11020037 | DOI Listing |
J Voice
January 2025
Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-ku, Fukuoka 815-8540, Japan.
Introduction: Vocal distortion, also known as a scream or growl, is used worldwide as an essential technique in singing, especially in rock and metal, and as an ethnic voice in Mongolian singing. However, the production mechanism of vocal distortion is not yet clearly understood owing to limited research on the behavior of the larynx, which is the source of the distorted voice.
Objectives: This study used high-speed digital imaging (HSDI) to observe the larynx of professional singers with exceptional singing skills and determine the laryngeal dynamics in the voice production of various vocal distortions.
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
Laboratory of Molecular Spectroscopy, Institute of Chemistry, ELTE Eötvös Loránd University, PO Box 32, H-1518 Budapest, Hungary; Centre for Astrophysics and Space Science, ELTE Eötvös Loránd University, PO Box 32, H-1518 Budapest, Hungary. Electronic address:
γ-valerolactone (GVL) and its unmethylated counterpart, γ-butyrolactone (GBL), are important compounds with a wide range of potential uses. For example, GVL is proposed as an ideal alternative renewable energy source, while GBL can be utilized as an electrolyte. Understanding the combustion mechanisms of these compounds is crucial for optimizing their use as energy sources and monitoring the products formed during combustion.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
School of Physical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S C Mullick Road, Kolkata 700032, INDIA, Kolkata, 700032, INDIA.
The breaking of inversion symmetry combined with spin-orbit coupling, can give rise to intrigu- ing quantum phases and collective excitations. Here, we report systematic temperature dependent Raman scattering and theoretical calculations of phonon modes across the inversion symmetry- breaking structural transitions in a quasi-one-dimensional compound (TaSe4)3I. Our investigation revealed the emergence of three additional Raman-active modes in Raman spectra of the low- temperature (LT) non-centrosymmetric (NC) structure of the material.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Xinjiang Key Laboratory of Solid State Physics and Devices, Xinjiang University, Urumqi 830017, China.
The collisional energy transfer between vibrational excited H2(1, 7) and CO2 was investigated by exciting H2 to a vibrational excited state of v = 1, J = 7 by the stimulated Raman scattering technique. The coherent anti-Stokes Raman spectroscopy (CARS) technique determined that H2 was excited to the H2(1, 7) state. Varying the cuvette temperature, the number of H2(1, 7) particles was found to increase with the increase in H2 molar ratio α by scanning the intensity of the CARS spectrum, with peaks at different α at a temperature of 363 ± 15 K, but the peak temperature was not sensitive to α.
View Article and Find Full Text PDFJ Chem Phys
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.
Vibro-polaritons are hybrid light-matter states that arise from the strong coupling between the molecular vibrational transitions and the photons in an optical cavity. Developing theoretical and computational methods to describe and predict the unique properties of vibro-polaritons is of great significance for guiding the design of new materials and experiments. Here, we present the ab initio cavity Born-Oppenheimer density functional theory (CBO-DFT) and formulate the analytic energy gradient and Hessian as well as the nuclear and photonic derivatives of dipole and polarizability within the framework of CBO-DFT to efficiently calculate the harmonic vibrational frequencies, infrared absorption, and Raman scattering spectra of vibro-polaritons as well as to explore the critical points on the cavity potential energy surface.
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