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We present the results of high-level electronic structure and dynamics simulations of the photoactive protein Dreiklang. With the goal of understanding the details of the Dreiklang photocycle, we carefully characterize the excited states of the ON- and OFF-forms of Dreiklang. The key finding of our study is the existence of a low-lying excited state of a charge-transfer character in the neutral ON form and that population of this state, which is nearly isoenergetic with the locally excited bright state, initiates a series of steps that ultimately lead to the formation of the hydrated dark chromophore (OFF state). These results allow us to refine the mechanistic picture of Dreiklang's photocycle and photoactivation.
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http://dx.doi.org/10.1021/acs.jpcb.0c09221 | DOI Listing |
J Synchrotron Radiat
November 2025
State Key Laboratory of Chemical Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
This study develops an integrated X-ray absorption spectroscopy (XAS) photoemission electron microscopy (PEEM) platform on beamline BL09U at the Shanghai Synchrotron Radiation Facility (SSRF), enabling nanoscale characterization of complex materials through energy-resolved imaging and local-area XAS. By using the wide range of energy tunability, full access to different polarizations and PEEM's surface sensitivity, we have established a gap-monochromator control system under the EPICS framework to synchronize the elliptically polarized undulator (EPU) gap and monochromator energy dynamically, optimizing photon flux stability for absorption fine structure analysis. Combining X-ray magnetic circular dichroism (XMCD) and X-ray magnetic linear dichroism (XMLD) with PEEM and local-area XAS, this platform achieves concurrent mapping of electronic structures and magnetic domains in ferromagnetic nano-patterns, as demonstrated through our studies of NiFe Permalloy using this system.
View Article and Find Full Text PDFJ Chem Phys
September 2025
Yusuf Hamied Department of Chemistry. Lensfield Road, Cambridge CB2 1EW, United Kingdom.
Folding and unfolding in molecules as simple as short hydrocarbons and as complicated as large proteins continue to be an active research field. Here, we investigate folding in n-C14H30 using both density functional theory (DFT)/B3LYP calculations of 27 772 local minima and a kinetic transition network calculated for a previously reported potential energy surface (PES) obtained by fitting roughly 250 000 B3LYP energies. In addition to generating a database of minima and the transition states that connect them, these calculations and the PES based on them have been used to develop a simple and accurate model for the energy landscape.
View Article and Find Full Text PDFACS Nano
September 2025
State Key Laboratory of Chemo and Biosensing, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Optical imaging offers high sensitivity and specificity for noninvasive cancer detection, but conventional techniques suffer from limited probe accumulation, tissue autofluorescence, and poor depth resolution. Afterglow luminescence overcomes autofluorescence by emitting persistent light after excitation, yet its utility in vivo remains hindered by weak tumor enrichment and two-dimensional readouts lacking spatial context. Here, we report luminescent-magnetic nanoparticles (LM-NPs) coencapsulating luminescent trianthracene (TA) molecules and iron oxide cores within the amphiphilic polymer pluronic-F127.
View Article and Find Full Text PDFNat Commun
September 2025
Institute of Neurosciences and Medicine, Brain & Behaviour (INM-7), Research Centre Juelich; Wilhelm-Johnen-Straße 1, Juelich, Germany.
Autism is a neurodevelopmental condition associated with altered resting-state brain function. An increased excitation-inhibition ratio is discussed as a pathomechanism but in-vivo evidence of disturbed neurotransmission underlying functional alterations remains scarce. We compare local resting-state brain activity and neurotransmitter co-localizations between autism (N = 405, N = 395) and neurotypical controls (N = 473, N = 474) in two independent cohorts and correlate them with excitation-inhibition changes induced by glutamatergic (ketamine) and GABAergic (midazolam) medication.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2025
Department of Physics, Tuskegee University, 1200 West Montgomery Road, 106 Chappie James, Tuskegee, Alabama, 36088-1920, UNITED STATES.
Spin qubit defects in two-dimensional materials have a number of advantages over those in three-dimensional hosts including simpler technologies for the defect creation and control, as well as qubit accessibility. In this work, we select the VBCB defect in the hexagonal boron nitride (hBN) as a possible optically controllable spin qubit and explain its triplet ground state and neutrality. In this defect a boron vacancy is combined with a carbon dopant substituting the closest boron atom to the vacancy.
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