Topic
Ultraviolet light
About: Ultraviolet light is a research topic. Over the lifetime, 49494 publications have been published within this topic receiving 843151 citations.
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TL;DR: Evidence that UV light initiates mutagenesis by producing unstable changas directly in genic DNA is interpreted as a repair process, blocked by the machinery of RNA and protein synthesis and by the presence of certain basic dyes.
Abstract: Post treatment with basic dyes, in concentrations that retard cell division, was found to influence the tnduction of mutations to prototrophy by UV light in a tyrosine-requirtng strain of E.Coli. Pyronin, which is unique among the dyes in tts selective affinity for RNA, was found to duplicate the effects of chloramphenicol or amino acfd deprtvatfon in causfng the rapid and irreversible loss of potential prototrophs (mutation frequency decline, or MFD). Acriflavtne, methyl green. crystal violet, methylene blue, and toluidine blue, all of which are known to combine with DNA, delay or retard the occurrence of MFD under conditions of amino acid deprivation. When acriflavine is removed from its combination with cellular components by the addition of an excess of sodium deoxyrtbonucleate, MFD begins promptly. The same basic dyes that delay MFD were also found to interfere with the fixation of mutations (MF) in an amino acid- enriched medium, and to cause marked enhancement of the mutagenic potency of low doses of UV light. While showing no independent mutagenic activity for unirradiated bacteria, all the dyes except pyronin increased the yield of induced mutations signtficantly when added to the enriched medium upon which trradiated bacteria were incubated.These results were interpreted asmore » evidence that UV light initiates mutagenesis by producing unstable changas directly in genic DNA. MFD is interpreted as a repair process, blocked by the machinery of RNA and protein synthesis and by the presence of certain basic dyes.« less
140 citations
Patent•
26 Jul 1996
TL;DR: A photo-catalyzer for deodorizing, cleaning, sterilizing, and water purifying operations includes a substrate, a titanium dioxide film disposed on the substrate and functioning as a photo catalyst as discussed by the authors.
Abstract: A photo-catalyzer for deodorizing, cleaning, sterilizing, and water purifying operations includes a substrate, a titanium dioxide film disposed on the substrate and functioning as a photo-catalyst, and a light-emitting diode disposed adjacent to the titanium dioxide film and producing ultraviolet light having a wavelength from 360 to 400 nm onto the titanium dioxide film. The photo-catalyzer can be used in places where there is no sunlight because it is optionally provided with a light-emitting diode. The light-emitting diode does not require a large installation space because it is an extremely small light-emitting device. Hence, the photo-catalyzer has a compact structure and can be used easily anywhere, including small places. The substrate can be fabricated into a variety of useful appliances to take advantage of the strong oxidizing properties of the photo-catalyzer. Devices comprising a photo-catalyzer may be used for deodorizing, destroying or repelling micro-organisms, and including undertaking air or water purification.
139 citations
TL;DR: In this article, the authors demonstrate both theoretically and experimentally an effective method to break the dipole-forbidden rule in SnO2 via nano-engineering its crystalline structure.
Abstract: It is commonly believed that bulk SnO2 is not a suitable ultraviolet (UV) light emitter due to the dipole-forbidden nature of its band-edge states, which has hindered its potential use in optical applications. Here, we demonstrate both theoretically and experimentally an effective method to break the dipole-forbidden rule in SnO2 via nano-engineering its crystalline structure. Furthermore, we designed and fabricated a prototypical UV-light-emitting diode (LED) based on SnO2 thin films. Our methodology is transferable to other semiconductors with ‘forbidden’ energy gaps, offering a promising route toward adding new members to the family of light-emitting materials.
139 citations
TL;DR: It is demonstrated that rIL-12 can prevent UV-induced local immunosuppression and overcomeUV-induced hapten-specific tolerance.
139 citations
Patent•
28 Feb 1990
TL;DR: In this article, an integrated circuit amplifier with a random input offset voltage is adaptable such that the offset voltage may be cancelled out by applying ultraviolet light to the desired areas of the structure.
Abstract: An integrated circuit amplifier having a random input offset voltage is adaptable such that the input offset voltage may be cancelled out. An inverting input node is a floating input node and is coupled to a source of input signal by a first capacitor. A second capacitor is connected between the output of the amplifier and the floating node. An ultraviolet window above the second capacitor allows the floating node to be charged, by the application of ultraviolet light, to a voltage which effectively cancels the input offset voltage. The ultraviolet window and capacitor electrodes are arranged such that the ultraviolet light may strike only the desired areas of the structure.
139 citations