The spectroscopic study of molecular ions is of great importance to a variety of fields, but is challenging as ions are typically produced in plasmas containing many orders of magnitude more neutral molecules than ions. The successful technique of velocity modulation permits discrimination between ion and neutral absorption signals and has allowed the study of scores of molecular ions in the past quarter century. However, this technique has long been considered to be inappropriate for use with cavity-enhanced techniques, owing to the directional nature of the velocity modulation. Here we report what we believe to be the first demonstration of cavity-enhanced velocity modulation spectroscopy, utilizing a 2f phase-sensitive demodulation scheme. This approach offers the promise of combining very high-sensitivity spectroscopic techniques with ion-neutral discrimination, which could extend the applicability of velocity modulation to intrinsically weak transitions and to ions that cannot be produced in high abundance. The use of a cavity also permits Lamb dip spectroscopy, which offers higher resolution and precision in frequency measurements and may be useful in measuring collisional rate coefficients.
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http://dx.doi.org/10.1364/OL.35.001266 | DOI Listing |
J Xenobiot
December 2024
Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
The growing use of products containing rare earth elements (REEs) may lead to higher environmental emissions of these elements, which can potentially enter aquatic systems. Praseodymium (Pr) and europium (Eu) are widely used REEs with various applications. However, their ecotoxicological impacts remain largely unexplored, with poorly understood risks to wildlife.
View Article and Find Full Text PDFRecent advancements in flexible bioelectronics have enabled continuous, long-term stable interrogation and intervention of biological systems. However, effectively utilizing the interrogated data to modulate biological systems to achieve specific biomedical and biological goals remains a challenge. In this study, we introduce an AI-driven bioelectronics system that integrates tissue-like, flexible bioelectronics with cyber learning algorithms to create a long-term, real-time bidirectional b ioelectronic interface with o ptimized a daptive intelligent m odulation (BIO-AIM).
View Article and Find Full Text PDFACS Photonics
December 2024
Department of Electrical, Electronic and Communications Engineering, Institute of Smart Cities (ISC), Public University of Navarre (UPNA), 31006 Pamplona, Spain.
Spacetime metamaterials are opening new regimes of light-matter interactions based on the breaking of temporal and spatial symmetries, as well as intriguing concepts associated with synthetic motion. In this work, we investigate the continuous spatiotemporal translation symmetry of spacetime metamaterials with uniform modulation velocity. Using Noether's theorem, we demonstrate that such symmetry entails the conservation of the energy momentum.
View Article and Find Full Text PDFmedRxiv
December 2024
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.
Introduction: Dynamic modulation of grip occurs mainly within the major structures of the brain stem, in parallel with cortical control. This basic, but fundamental level of the brain, is robust to ill-formed feedback and to be useful, it may not require all the perceptual information of feedback we are consciously aware. This makes it viable candidate for using peripheral nerve stimulation (PNS), a form of tactile feedback that conveys intensity and location information of touch well but does not currently reproduce other qualities of natural touch.
View Article and Find Full Text PDFJ Biomech
December 2024
Research and Development Center of Biomedical Photonics, Orel State University, Orel, Russia.
Although there is currently sufficient information on various parameters of capillary blood flow, including the average values of blood velocity, there is no data on the dynamics of velocity and the mechanisms of its modulation in various parts of the capillary. The main idea of this work is to develop a tool and image data processing to study the characteristics of the capillary blood flow dynamics. In this study, using the developed method of high-speed videocapillaroscopy, the red blood cells (RBC) velocities in the arterial and venous parts of the nailfold capillaries were compared and a time-frequency analysis of the dynamics of the velocity signals with the calculation of phase coherence was performed.
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