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1. Lightweight UV-C disinfection system

   https://doi.org/10.1364/BOE.395659  

   She, Rosemary_C ; Chen, Dongyu ; Pak, Pil ; Armani, Deniz_K ; Schubert, Andreas ; Armani, Andrea_M ( July 2020 , Biomedical Optics Express)

   UV-C exposure is an effective disinfectant for a range of bacteria and viruses. As such, UV-C treatment, in combination with a chemical wipe, is a common cleaning protocol in medical facilities. Given the increase in severe bacterial and viral agents in society, having access to environmentally friendly disinfectant methods is of increasing interest. In response, we designed, constructed, and validated a UV-C disinfection system from readily accessible components. To improve the UV-C intensity, the enclosure interior was coated with chrome paint. The system is validated usingBacillus cereus, a gram-positive endospore-forming bacteria.

    

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2. UV-C inactivation of microorganisms in droplets on food contact surfaces using UV-C light-emitting diode devices

   https://doi.org/10.3389/frfst.2023.1182765  

   Sharma, Aakash ; Mahmoud, Housyn ; Pendyala, Brahmaiah ; Balamurugan, Sampathkumar ; Patras, Ankit ( May 2023 , Frontiers in Food Science and Technology)

   The main objective of this study was to investigate the effectiveness of ultraviolet light (UV-C) emitting diodes for the decontamination of stainless steel food contact surfaces. Listeria monocytogenes (ATCC 19115), Escherichia coli (ATCC 25922), and Salmonella enterica serovar Typhimurium (ATCC 700720) were chosen as challenge microorganisms. Target microorganisms were subjected to UV-C dosages of 0, 2, 4, 6, and 8 mJ cm −2 at an average fluence of 0.163 mW/cm 2 using a near-collimated beam operating at 279 nm wavelength. Escherichia coli showed lower sensitivity to UV-C light compared to Salmonella Typhimurium and followed first-order kinetics. Escherichia coli and Salmonella Typhimurium were reduced by more than 3-log 10 cycles at the maximum UV dosage of 12 mJ cm −2 . In contrast, Listeria monocytogenes followed the Weibull model with an apparent shoulder in the initial doses. A maximum reduction of 4.4-log 10 was achieved at the highest exposure level. This study showed that UV-C LED devices represent an excellent alternative for the inactivation of foodborne microorganisms in droplets. Results clearly demonstrate that UV-C LED devices can serve as an additional sanitation method to routine cleaning practices, which are commonly utilized in the food industry. 

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3. Thermoluminescence of UV-irradiated α-Al2O3:C,Mg

   https://doi.org/10.1016/j.jlumin.2020.117195  

   Trindade, N.M. ; Magalhães, M.G. ; Nunes, M.C.S. ; Yoshimura, E.M. ; Jacobsohn, L.G. ( July 2020 , Journal of Luminescence)
4. Recent Progress of Electrically Pumped AlGaN Diode Lasers in the UV-B and -C Bands

   https://doi.org/10.3390/photonics8070267  

   Hasan, Syed M. ; You, Weicheng ; Sumon, Md Saiful ; Arafin, Shamsul ( July 2021 , Photonics)

   The development of electrically pumped semiconductor diode lasers emitting at the ultraviolet (UV)-B and -C spectral bands has been an active area of research over the past several years, motivated by a wide range of emerging applications. III-Nitride materials and their alloys, in particular AlGaN, are the material of choice for the development of this ultrashort-wavelength laser technology. Despite significant progress in AlGaN-based light-emitting diodes (LEDs), the technological advancement and innovation in diode lasers at these spectral bands is lagging due to several technical challenges. Here, the authors review the progress of AlGaN electrically-pumped lasers with respect to very recent achievements made by the scientific community. The devices based on both thin films and nanowires demonstrated to date will be discussed in this review. The state-of-the-art growth technologies, such as molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD); and various foreign substrates/templates used for the laser demonstrations will be highlighted. We will also outline technical challenges associated with the laser development, which must be overcome in order to achieve a critical technological breakthrough and fully realize the potential of these lasers. 

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5. Fabrication and structural properties of AlN submicron periodic lateral polar structures and waveguides for UV-C applications

   https://doi.org/10.1063/1.4955033  

   Alden, D. ; Guo, W. ; Kirste, R. ; Kaess, F. ; Bryan, I. ; Troha, T. ; Bagal, A. ; Reddy, P. ; Hernandez-Balderrama, Luis H. ; Franke, A. ; et al ( June 2016 , Applied Physics Letters)