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Up-Regulation of Tumor Cell Sensitivity to Natural Cell-Mediated Cytotoxicity by UV Light Irradiation
Published in Ronald H. Goldfarb, Theresa L. Whiteside, Tumor Immunology and Cancer Therapy, 2020
Mirsada Begovic, Ronald B. Herberman, Elieser Gorelik
First, we tested whether UV treatment of MCA102 and MCA105 fibrosarcoma cells render them sensitive to lysis by normal spleen cells of C57BL/6 mice. Tumor cells were irradiated in vitro with UVC light from a germicidal lamp under laminar flow hood with a total dose of 610 J/m2, the incident-dose rate was 1.2 W/m2 as measured by a Black-Ray UV meter, Model J225 (American UV Co., Chatham, N J) (14–16).
Radiobiological research at Compton, 1964–1978
Published in Kiheung Kim, The Social Construction of Disease, 2006
However, Alper and Haig found more surprising results than in the previous experiment. To reduce phage T3 to 1 per cent of infectious activity, a dose of 103 ergs/mm2 of UV radiation from a standard germicidal lamp (wavelength 245 nm) would suffice. However, to effect a similar reduction in activity of scrapie material, a much larger dose of radiation, of more than 2.4×104 ergs/mm2 was required. In other words, the scrapie agent was extraordinarily resistant to deactivation by UV light (Alper et al. 1966: 281). The researchers themselves were confused by this extraordinary outcome. Clarke explains the situation at the time: When there was an assay involved, I was looking at mice every week to score. So that one can see a picture developing from fourteen or so weeks onwards up to thirty, the mice developing scrapie, and one can get a feel for a comparison between one example and another. So in the first experiment, I got a feeling early on that the irradiation that had been used was not effective, because there was no reduction compared with the controls. There are some months while the experiment is developing, when one has an opportunity to think about the implications of what has actually been happening. It was Tikvah Alper who suggested, because we got no reduction with the first experiment using ionizing radiation, that we should try ultraviolet light. Ultraviolet light of wavelength 245 was known to be viricidal or bactericidal. It was a common enough thing to use at that time, and so we did the experiment and we got no inactivation.(Clarke 2000b)
UV-Photokeratitis Associated with Germicidal Lamps Purchased during the COVID-19 Pandemic
Published in Ocular Immunology and Inflammation, 2021
Jesse D. Sengillo, Anne L. Kunkler, Charles Medert, Benjamin Fowler, Marissa Shoji, Nathan Pirakitikulr, Nimesh Patel, Nicolas A. Yannuzzi, Angela J. Verkade, Darlene Miller, David H Sliney, Jean-Marie Parel, Guillermo Amescua
Interestingly, other isolated reports of germicidal lamps associated with UV photokeratitis are reported. Stripp et al. documented a case series of 18 employees at a restaurant with photokeratitis after exposure to UV-C spectrum light bulbs that were inadvertently shipped and installed in insect light traps.24 Similar associations are documented after UV exposure at a night club14 and in public gatherings within the vicinity of UV light sources with damaged protective covers.12,13 Pertinent to our study, Leung and Ko reported a family of three adults with photokeratitis after exposure to a UV-C germicidal lamp early in the pandemic in Hong Kong.2 The present study confirms this association between light exposure from improperly used germicidal UV-lamps during the COVID-19 pandemic and photokeratitis and is first to report this entity in the United States. Unique to the present study, germicidal lamps were not only used in the homes of patients but exposure was also found to occur at patients’ workplace and during a dental procedure. It is important to note that although germicidal lamps are suggested by various news and media outlets as means of sanitation against COVID-19, the efficacy of alternative disinfection methods, such as ultrasonic waves, LED blue light, and UV radiation against COVID-19 virus are not currently established.
UV-C radiation during the pupal stage affects morphological changes of wings in Tribolium castaneum (Col; Tenebrionidae)
Published in International Journal of Radiation Biology, 2019
Jatuporn Tungjitwitayakul, Thippawan Yasanga, Nujira Tatun
The radiation source was a 17-watt UV germicidal lamp (TUV F17T8, Philips, Amsterdam, The Netherlands) measuring 58 × 2.5 cm2 and emitting radiation at a wavelength of 254 nm. The lamp was fixed to the ceiling of a test chamber (90 × 60 × 55 cm3). The stage on which the insects were exposed to radiation was 35 cm from the surface of the UV lamp. The dorsal sides of 0-day-old pupae were attached to a glass slide with conductive double-sided adhesive tape. The slides containing the pupae were exposed to UV-C radiation for 0, 1, 2, 4, 8, 16, 32, and 64 min and doses of UV-C in each exposure time was measured and presented as 0.2 W/cm2, 0.8 W/cm2, 3.2 W/cm2, 12.8 W/cm2, 51.2 W/cm2, 204.8 W/cm2, and 819.2 W/cm2, respectively. Three replicates of 20 pupae (0 days old) were used for each treatment. Bioassays were conducted at 28 ± 2 °C. After UV-C irradiation, the pupae were removed from the slides using a fine paint brush and kept for 7 days or until adult eclosion.
Colloidal synthesis of biocompatible iron disulphide nanocrystals
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
J. Santos-Cruz, R. E. Nuñez-Anita, S. A. Mayén-Hernández, O. Martínez-Alvarez, L. S. Acosta-Torres, J. de la Fuente-Hernández, E. Campos-González, M. Vega-González, M. C. Arenas-Arrocena
Photocatalytic activity was tested using 400 mL of methylene blue (MB) aqueous solution at a concentration of 2 × 1 0−5 mol L−1 and a pH of 6.7. Colloidal iron disulphide obtained at different temperatures were placed in 600 mL of the reactor. A quartz tube was used for the reactor for immersion of the lamp and the solution was stirred for the entire time of the test. The solution in the reactor was irradiated with a commercial germicidal lamp (λ = 252 nm, 11 W). The irradiation times were 0–150 min in incremental steps of 20 min. The residual concentration was quantified by a UV–Visible absorption spectroscopy at 663 nm, previously calibrated with external calibration standards (2, 1.5, 1.0, 0.5 and 0.25 × 10−5 mol L−1). The concentration for photocatalytic assays of the pyrite powder was 1 g L−1 in all cases. The samples were carried out by triplicate and the results shown are the mean value of these three measurements.