Visualization of vibrational-resolution charge transfer enhanced resonance Raman scattering spectroscopy

Raman Spectroscopy: A Novel Technology for Gastric Cancer Diagnosis

Gastric cancer is usually diagnosed at late stage and has a high mortality rate, whereas early detection of gastric cancer could bring a better prognosis. Conventional gastric cancer diagnostic methods suffer from long diagnostic times, severe trauma, and a high rate of misdiagnosis and rely heavily on doctors’ subjective experience. Raman spectroscopy is a label-free molecular vibrational spectroscopy technique that identifies the molecular fingerprint of various samples based on the inelastic scattering of monochromatic light. Because of its advantages of non-destructive, rapid, and accurate detection, Raman spectroscopy has been widely studied for benign and malignant tumor differentiation, tumor subtype classification, and section pathology diagnosis. This paper reviews the applications of Raman spectroscopy for the in vivo and in vitro diagnosis of gastric cancer, methodology related to the spectroscopy data analysis, and presents the limitations of the technique.

Excited States Symmetry Breaking and In-Plane Polarization Cause Chiral Reversal in Diastereomers

In this work, we investigate the electronic transitions and chirality of three isomers of huge conjugated systems: asymmetric diastereomers (MMMM) and two symmetrical diastereomers (PMPM and PPMM). The physical mechanism of flipping has been studied theoretically. The new ribbon-shaped polycyclic aromatic hydrocarbons (PAHs) molecule is formed by connecting three graphene-like systems with large conjugated π orbitals. By calculating and analyzing electromagnetic interaction decomposition over distance, it can be found that the chirality reversal of different energies is caused by the symmetrical fracture of TMDM in the Z direction. The chirality reversal at the same energy is caused by the in-plane polarization of the TMDM along the Y direction.