The damage threshold of an Au-coated flat mirror, one of the reflective optics installed on the FEL-2 beamline of the Dalian Coherent Light Source, China, upon far-UV free-electron laser irradiation is evaluated. The surface of the coating is characterized by profilometer and optical microscope. A theoretical approach of the phenomenon is also presented, by application of conventional single-pulse damage threshold calculations, a one-dimensional thermal diffusion model, as well as finite-element analysis with ANSYS.
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http://dx.doi.org/10.1107/S1600577524005332 | DOI Listing |
Sci Rep
January 2025
Laser Research Center, Vilnius University, Saulėtekio Avenue 10, LT-10223, Vilnius, Lithuania.
We present a comparative experimental study of supercontinuum generation in undoped scintillator crystals: bismuth germanate (BGO), yttrium orthosilicate (YSO), lutetium oxyorthosilicate (LSO), lutetium yttrium oxyorthosilicate (LYSO) and gadolinium gallium garnet (GGG), pumped by 180 fs fundamental harmonic pulses of an amplified Yb:KGW laser. In addition to these materials, experiments in yttrium aluminium garnet (YAG), potassium gadolinium tungstate (KGW) and lithium tantalate (LT) were performed under identical experimental settings (focusing geometry and sample thickness), which served for straightforward comparison of supercontinuum generation performances. The threshold and optimal (that produces optimized red-shifted spectral extent) pump pulse energies for supercontinuum generation were evaluated from detailed measurements of spectral broadening dynamics.
View Article and Find Full Text PDFNeurochem Res
January 2025
Huazhong University of Science and Technology, Tongji Medical College, Wuhan, Hubei, 430000, China.
Epilepsy (EP) is a neurological disorder characterized by abnormal, sudden neuronal discharges. Seizures increase extracellular glutamate levels, causing excitotoxic damage. Glutamate transporter type 1 (GLT-1) and its human homologue excitatory amino acid transporter-2 (EAAT2) clear 95% of extracellular glutamate.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
University of Washington, Seattle, WA, USA.
Background: Leveraging non-invasive ultra-high field, 7 Tesla (7T) MRI, with increased signal-to-noise ratio and improved soft tissue contrast afforded by 7T allows us to accurately map tissue microstructure. We aim to use 7T MR Elastography (MRE), 7T Diffusion Tensor Imaging (DTI), 3T amyloid-PET, and Preclinical Alzheimer Cognitive Composite (PACC) score to determine the relationships between these metrics in a cohort of older individuals with either normal cognition (CN), mild cognitive impairment (MCI), or Alzheimer's Disease (AD).
Methods: 7T MRE, 7T DTI, 3T PET (Fig.
Alzheimers Dement
December 2024
All India Institute of Medical Sciences, Nagpur, Nagpur, Maharashtra, India.
Background: Multiple Sclerosis (MS) is a chronic, etiologically complex disease of the central nervous system (CNS) characterized by inflammation, demyelination, and neuronal damage. MS has seven categories based on disease course. Seventy to eighty percent of individuals with MS initially develop a clinical pattern with periodic relapses and remissions, called relapsing-remitting MS (RRMS).
View Article and Find Full Text PDFInt J Radiat Biol
January 2025
N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow, Russia.
Background: Enumeration of residual DNA repair foci 24 hours or more after exposure to ionizing radiation (IR) is often used to assess the efficiency of DNA double-strand break repair. However, the relationship between the number of residual foci in irradiated cells and the radiation dose is still poorly understood. The aim of this work was to investigate the dose responses for residual DNA repair foci in normal human fibroblasts after X-ray exposure in the absorbed dose range from 0.
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