We demonstrate that a recently introduced family of direct-emitting green laser diodes is a simple yet efficient light source for excitation of NV centers in diamond. Thanks to their fast (sub-ns) response time, these sources are suitable for a broad variety of measurements, including pulsed optically detected magnetic resonance (ODMR) and fluorescence lifetime imaging. This feature, together with a drastically simplified design, is a significant advantage over the traditional excitation system comprising an Nd: YAG laser switched by an acousto-optic modulator. We introduce a simple design for such a compact laser system and experimentally verify that it enables simultaneous lifetime and ODMR measurements on NV centers. In particular, we find that the NV(-) charge state remains stable in spite of the short excitation wavelength of the new source.
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Korean J Physiol Pharmacol
January 2025
Department of Pharmacology, Catholic Kwandong University College of Medicine, Gangneung 25601, Korea.
Neurosteroids play an important role as endogenous neuromodulators that are locally produced in the central nervous system and rapidly change the excitability of neurons and the activation of microglial cells and astrocytes. Here we review the mechanisms of synthesis, metabolism, and actions of neurosteroids in the central nervous system. Neurosteroids are able to play a variety of roles in the central nervous system under physiological conditions by binding to membrane ion channels and receptors such as gamma-aminobutyric acid type A receptors, Nmethyl- D-aspartate receptors, L- and T-type calcium channels, and sigma-1 receptors.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC, H3A 2B4, Canada.
Excitation-inhibition (E/I) imbalance is theorized as a key mechanism in the pathophysiology of epilepsy, with ample research focusing on elucidating its cellular manifestations. However, few studies investigate E/I imbalance at the macroscale, whole-brain level, and its microcircuit-level mechanisms and clinical significance remain incompletely understood. Here, the Hurst exponent, an index of the E/I ratio, is computed from resting-state fMRI time series, and microcircuit parameters are simulated using biophysical models.
View Article and Find Full Text PDFAJNR Am J Neuroradiol
January 2025
From the Department of Radiology, Medical Physics (MML, TJC), Department of Interventional Radiology (NS, GAC), Department of Surgery and Large Animal Studies (MAN), and the Department of Statistics (MG), University of Chicago, Chicago, IL, USA; Department of Anesthesiology (SPR), University of Illinois, Chicago, IL, USA; Department of Radiology (MSS), University of Massachusetts Chan Medical School, Worcester, MA, USA; Department of Radiology, Biomedical Engineering and Imaging Institute (Current affiliation MML), Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mount Carmel Health Systems (Current affiliation GAC), Columbus, OH, USA.
Background And Purpose: In acute ischemic stroke, the amount of "local" CBF distal to the occlusion, i.e. all blood flow within a region whether supplied antegrade or delayed and dispersed through the collateral network, may contain valuable information regarding infarct growth rate and treatment response.
View Article and Find Full Text PDFRep Prog Phys
January 2025
Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Aarhus, Midtjylland, 8000, DENMARK.
Irradiation of condensed matter with ionizing radiation generally causes direct photoionization as well as secondary processes that often dominate the ionization dynamics. Here, large helium (He) nanodroplets with radius ≳ 40 nm doped with lithium (Li) atoms are irradiated with extreme ultraviolet (XUV) photons of energy hν ≥ 44.4 eV and indirect ionization of the Li dopants is observed in addition to direct photoionization of the He droplets.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Departament de Farmàcia i Tecnologia Farmacèutica, i Fisicoquímica, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona (UB), 08028 Barcelona, Spain.
Incorporation of environment and vibronic effects in simulations of optical spectra and excited state dynamics is commonly done by combining molecular dynamics with excited state calculations, which allows to estimate the spectral density describing the frequency-dependent system-bath coupling strength. The need for efficient sampling, however, usually leads to the adoption of classical force fields despite well-known inaccuracies due to the mismatch with the excited state method. Here, we present a multiscale strategy that overcomes this limitation by combining EMLE simulations based on electrostatically embedded ML potentials with the QM/MMPol polarizable embedding model to compute the excited states and spectral density of 3-methyl-indole, the chromophoric moiety of tryptophan that mediates a variety of important biological functions, in the gas phase, in water solution, and in the human serum albumin protein.
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