Ultraviolet light

About: Ultraviolet light is a research topic. Over the lifetime, 49494 publications have been published within this topic receiving 843151 citations.

Ultraviolet light and ocular diseases.

Abstract: The objective of this study is to review the association between ultraviolet (UV) light and ocular diseases. The data are sourced from the literature search of Medline up to Nov 2012, and the extracted data from original articles, review papers, and book chapters were reviewed. There is a strong evidence that ultraviolet radiation (UVR) exposure is associated with the formation of eyelid malignancies [basal cell carcinoma (BCC) and squamous cell carcinoma (SCC)], photokeratitis, climatic droplet keratopathy (CDK), pterygium, and cortical cataract. However, the evidence of the association between UV exposure and development of pinguecula, nuclear and posterior subcapsular cataract, ocular surface squamous neoplasia (OSSN), and ocular melanoma remained limited. There is insufficient evidence to determine whether age-related macular degeneration (AMD) is related to UV exposure. It is now suggested that AMD is probably related to visible radiation especially blue light, rather than UV exposure. From the results, it was concluded that eyelid malignancies (BCC and SCC), photokeratitis, CDK, pterygium, and cortical cataract are strongly associated with UVR exposure. Evidence of the association between UV exposure and development of pinguecula, nuclear and posterior subcapsular cataract, OSSN, and ocular melanoma remained limited. There is insufficient evidence to determine whether AMD is related to UV exposure. Simple behaviural changes, appropriate clothing, wearing hats, and UV blocking spectacles, sunglasses or contact lens are effective measures for UV protection.

The Combination of Glycolic Acid and Hydroquinone or Kojic Acid for the Treatment of Melasma and Related Conditions

Abstract: BACKGROUND Melasma continues to be a difficult problem. Although the cause is genetic, the condition is aggravated with sunlight, birth control pills, and pregnancy. Although hydroquinone is effective and has been available for years, a new product, kojic acid, has the advantage of being pharmaceutically more stable and, also, a tyrosinase inhibitor. OBJECTIVE To evaluate on melasma and related conditions two similar formulations of glycolic acid/hydroquinone and glycolic acid/kojic acid. The therapeutic index of the two formulations is examined. METHODS Thirty-nine patients were treated with kojic acid on one side of the face and hydroquinone in a similar vehicle on the other side of the face. The results were documented by a clinical investigator and with Wood's light examination combined with ultraviolet light photography. RESULTS Fifty-one percent of the patients responded equally to hydroquinone and kojic acid. Twenty-eight percent had a more dramatic reduction in pigment on the kojic acid side; whereas 21% had a more dramatic improvement with the hydroquinone formulation. These results were not statistically different. The kojic acid preparation was more irritating. CONCLUSION Both glycolic acid/kojic acid and glycolic acid/hydroquinone topical skin care products are highly effective in reducing the pigment in melasma patients. Both formulations should be available to the dermatologist to satisfy the patient's preferences.

Perioperative COVID-19 Defense: An Evidence-Based Approach for Optimization of Infection Control and Operating Room Management.

Abstract: We describe an evidence-based approach for optimization of infection control and operating room management during the coronavirus disease 2019 (COVID-19) pandemic. Confirmed modes of viral transmission are primarily, but not exclusively, contact with contaminated environmental surfaces and aerosolization. Evidence-based improvement strategies for attenuation of residual environmental contamination involve a combination of deep cleaning with surface disinfectants and ultraviolet light (UV-C). (1) Place alcohol-based hand rubs on the intravenous (IV) pole to the left of the provider. Double glove during induction. (2) Place a wire basket lined with a zip closure plastic bag on the IV pole to the right of the provider. Place all contaminated instruments in the bag (eg, laryngoscope blades and handles) and close. Designate and maintain clean and dirty areas. After induction of anesthesia, wipe down all equipment and surfaces with disinfection wipes that contain a quaternary ammonium compound and alcohol. Use a top-down cleaning sequence adequate to reduce bioburden. Treat operating rooms using UV-C. (3) Decolonize patients using preprocedural chlorhexidine wipes, 2 doses of nasal povidone-iodine within 1 hour of incision, and chlorhexidine mouth rinse. (4) Create a closed lumen IV system and use hub disinfection. (5) Provide data feedback by surveillance of Enterococcus, Staphylococcus aureus, Klebsiella, Acinetobacter, Pseudomonas, and Enterobacter spp. (ESKAPE) transmission. (6) To reduce the use of surgical masks and to reduce potential COVID-19 exposure, use relatively long (eg, 12 hours) staff shifts. If there are 8 essential cases to be done (each lasting 1-2 hours), the ideal solution is to have 2 teams complete the 8 cases, not 8 first case starts. (7) Do 1 case in each operating room daily, with terminal cleaning after each case including UV-C or equivalent. (8) Do not have patients go into a large, pooled phase I postanesthesia care unit because of the risk of contaminating facility at large along with many staff. Instead, have most patients recover in the room where they had surgery as is done routinely in Japan. These 8 programmatic recommendations stand on a substantial body of empirical evidence characterizing the epidemiology of perioperative transmission and infection development made possible by support from the Anesthesia Patient Safety Foundation (APSF).

Evidence for dark-reactivation of ultraviolet light damage in mouse L cells.

Abstract: The survival of colony-forming ability of mouse L cells after ultraviolet light (UVL) irradiation can be changed drastically by immediately incubating the cells in growth medium to which caffeine has been added. The nature of this effect is similar to previous results obtained by other workers for UVL-irradiated bacteria containing a dark-reactivation system. The nature of these similarities is as follows: The effect of caffeine on L cells is concentration-dependent in the range of 0.3 to 5 mM, and it is purely a postirradiation phenomenon, being dependent on the time after irradiation that caffeine is added to the cells. Cells incubated for one generation time in the absence of caffeine show no decreased colony-forming ability when incubated in its presence. The caffeine effect is not seen if the cells are exposed to ionizing radiation instead of UVL irradiation. Substitution of some of the thymine moieties of L cell DNA with BUdR sensitizes the cell to UVL, but when such cells are plated in the presence...

Far ultraviolet surgical and dental procedures

Abstract: A method and apparatus are described for photoetching organic biological matter without requiring heat as the dominant etching mechanism. Far-ultraviolet radiation of wavelengths less than 200 nm are used to selectively remove organic biological material, where the radiation has an energy fluence sufficiently great to cause ablative photodecomposition. Either continuous wave or pulse radiation can be used, a suitable ultraviolet light source being an ArF excimer laser having an output at 193 nm. The exposed biological material is ablatively photodecomposed without heating or damage to the rest of the organic material. Medical and dental applications include the removal of damaged or unhealthy tissue from bone, removal of skin lesions, cutting or sectioning healthy tissue, and the treatment of decayed teeth.