Photons with spin angular momentum possess intrinsic chirality, which underpins many phenomena including nonlinear optics, quantum optics, topological photonics and chiroptics. Intrinsic chirality is weak in natural materials, and recent theoretical proposals aimed to enlarge circular dichroism by resonant metasurfaces supporting bound states in the continuum that enhance substantially chiral light-matter interactions. Those insightful works resort to three-dimensional sophisticated geometries, which are too challenging to be realized for optical frequencies. Therefore, most of the experimental attempts showing strong circular dichroism rely on false/extrinsic chirality by using either oblique incidence or structural anisotropy. Here we report on the experimental realization of true/intrinsic chiral response with resonant metasurfaces in which the engineered slant geometry breaks both in-plane and out-of-plane symmetries. Our result marks, to our knowledge, the first observation of intrinsic chiral bound states in the continuum with near-unity circular dichroism of 0.93 and a high quality factor exceeding 2,663 for visible frequencies. Our chiral metasurfaces may lead to a plethora of applications in chiral light sources and detectors, chiral sensing, valleytronics and asymmetric photocatalysis.
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http://dx.doi.org/10.1038/s41586-022-05467-6 | DOI Listing |
J Am Chem Soc
January 2025
Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich 8093, Switzerland.
We report spectroscopic and spectrometric experiments that probe the London dispersion interaction between -butyl substituents in three series of covalently linked, protonated -pyridines in the gas phase. Molecular ions in the three test series, along with several reference molecules for control, were electrosprayed from solution into the gas phase and then probed by infrared multiphoton dissociation spectroscopy and trapped ion mobility spectrometry. The observed N-H stretching frequencies provided an experimental readout diagnostic of the ground-state geometry of each ion, which could be furthermore compared to a second, independent structural readout via the collision cross section.
View Article and Find Full Text PDFCell Mol Biol Lett
January 2025
State Key Laboratory of Pharmaceutical Biotechnology, Department of Gastroenterology, Drum Tower Hospital, Nanjing University Medical School, Nanjing University, Nanjing, 210093, Jiangsu, China.
Shiga toxin (Stx)-induced hemolytic uremic syndrome (HUS) poses a life-threatening complication for which a definitive treatment remains elusive. To exert its cytotoxic effect on renal cells, Stx must be delivered from the infected intestines to the kidney. However, the mechanism underlying Stx delivery remains unclear.
View Article and Find Full Text PDFAnal Bioanal Chem
January 2025
Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China.
Insulin bound with ligand molecules can improve its bioavailability in oral formulations. In this work, the interactions between insulin and bile acids of taurocholic acid (TCA) and glycocholic acid (GCA) are characterized using different mass spectrometry (MS) methods. Electrospray (ESI)-MS analysis revealed that GCA and TCA could interact with insulin individually or together through non-covalent bonds, and the products included mGCA-insulin, nTCA-insulin, and mGCA-nTCA-insulin complexes.
View Article and Find Full Text PDFSci Rep
January 2025
School of Mathematics and Statistics, Shaoguan University, Shaoguan, 512005, China.
Recently, deep latent variable models have made significant progress in dealing with missing data problems, benefiting from their ability to capture intricate and non-linear relationships within the data. In this work, we further investigate the potential of Variational Autoencoders (VAEs) in addressing the uncertainty associated with missing data via a multiple importance sampling strategy. We propose a Missing data Multiple Importance Sampling Variational Auto-Encoder (MMISVAE) method to effectively model incomplete data.
View Article and Find Full Text PDFMethods Enzymol
January 2025
Department of Chemistry, University of California, Davis, CA, United States; Department of Molecular and Cellular Biology, University of California, Davis, CA, United States. Electronic address:
Adenosine deaminases acting on RNAs (ADARs) are a class of RNA editing enzymes found in metazoa that catalyze the hydrolytic deamination of adenosine to inosine in duplexed RNA. Inosine is a nucleotide that can base pair with cytidine, therefore, inosine is interpreted by cellular processes as guanosine. ADARs are functionally important in RNA recoding events, RNA structure modulation, innate immunity, and can be harnessed for therapeutically-driven base editing to treat genetic disorders.
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