The transient appearance of bright spots in the beam profile of optical filaments formed in xenon is experimentally investigated. Fluence profiles are recorded with high-speed optical cameras at the kilohertz repetition rate of the laser source. A statistical analysis reveals a thresholdlike appearance of heavy-tailed fluence distributions together with the transition from single to multiple filamentation. The multifilament scenario exhibits near-exponential probability density functions, with extreme events exceeding the significant wave height by more than a factor of 10. The extreme events are isolated in space and in time. The macroscopic origin of these experimentally observed heavy-tail statistics is shown to be local refractive index variations inside the nonlinear medium, induced by multiphoton absorption and subsequent plasma thermalization. Microscopically, mergers between filament strings appear to play a decisive role in the observed rogue wave statistics.
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http://dx.doi.org/10.1103/PhysRevLett.111.243903 | DOI Listing |
Viruses
January 2025
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China.
is a common opportunistic pathogen associated with nosocomial infections. The primary treatment for infections typically involves antibiotics, which can lead to the emergence of multidrug-resistant strains. Therefore, there is a pressing need for safe and effective alternative methods.
View Article and Find Full Text PDFAntimicrob Agents Chemother
January 2025
Medical Mycology Unit, Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India.
causes life-threatening infections in immunocompromised hosts, including hospitalized neonates. This pathogen is intrinsically resistant to fluconazole, while uncommon strains resistant to multiple antifungal drugs, including voriconazole, amphotericin B, and echinocandins, have also been reported from healthcare environments. Thus, understanding how spread, persist, and adapt to healthcare settings could help us develop better infection management strategies.
View Article and Find Full Text PDFA coherent concatenation of multiple solitary waves may lead to a stable infrared and visible broadband filament in a ceramic YAG polycrystal. This self-trapped soliton train is leveraged to implement self-referenced multiplex coherent anti-Stokes Raman scattering (SR-M-CARS) imaging. Simulations and experiments illustrating the filamentation process and the concatenation of focusing-defocusing cycles in ceramic and crystal YAG are presented.
View Article and Find Full Text PDFOphthalmol Sci
November 2024
Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.
Purpose: The diagnosis of fungal keratitis using potassium hydroxide (KOH) smears of corneal scrapings enables initiation of the correct antimicrobial therapy at the point-of-care but requires time-consuming manual examination and expertise. This study evaluates the efficacy of a deep learning framework, dual stream multiple instance learning (DSMIL), in automating the analysis of whole slide imaging (WSI) of KOH smears for rapid and accurate detection of fungal infections.
Design: Retrospective observational study.
GMS Hyg Infect Control
December 2024
Department of ENT, Sree Balaji Medical college Chromepet, Chennai, Tamil Nadu, India.
Actinomycosis is an endogenous bacterial infection caused by . This bacterium reside on the mucosa of oral cavity, tonsils, and genitourinary tract. Any insult such as trauma, surgery, or foreign body disrupts the mucosal barrier and gives entry to the underlying tissue to cause disease.
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