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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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Journal ArticleDOI
TL;DR: The therapy met with unprecedented success from the outset, leaving little perceived need to understand underlying science, but in recent years there has been a new found interest in the basic aspects of psoralen photobiology and molecular mechanistic events contributing to therapeutic responses as well as to the development of skin cancers in PUVA patients.

182 citations

Journal ArticleDOI
TL;DR: The cell cycle is restricted via p53-dependent and -independent pathways to facilitate repair processes prior to replication and division, and failure to rescue the cell from replication block will ultimately lead to cell death, and apoptosis may be induced.
Abstract: Exposure to the solar ultraviolet spectrum that penetrates the Earth's stratosphere (UVA and UVB) causes cellular DNA damage within skin cells. This damage is elicited directly through absorption of energy (UVB), and indirectly through intermediates such as sensitizer radicals and reactive oxygen species (UVA). DNA damage is detected as strand breaks or as base lesions, the most common lesions being 8-hydroxydeoxyguanosine (8OHdG) from UVA exposure and cyclobutane pyrimidine dimers from UVB exposure. The presence of these products in the genome may cause misreading and misreplication. Cells are protected by free radical scavengers that remove potentially mutagenic radical intermediates. In addition, the glutathione-S-transferase family can catalyze the removal of epoxides and peroxides. An extensive repair capacity exists for removing (1) strand breaks, (2) small base modifications (8OHdG), and (3) bulky lesions (cyclobutane pyrimidine dimers). UV also stimulates the cell to produce early response genes that activate a cascade of signaling molecules (e.g., protein kinases) and protective enzymes (e.g., haem oxygenase). The cell cycle is restricted via p53-dependent and -independent pathways to facilitate repair processes prior to replication and division. Failure to rescue the cell from replication block will ultimately lead to cell death, and apoptosis may be induced. The implications for UV-induced genotoxicity in disease are considered.

182 citations

Journal ArticleDOI
TL;DR: The present study provides evidence for an increased skin cancer risk for patients treated with either broadband or narrowband UVB phototherapy, but only one patient developed skin cancer - an in situ melanoma.
Abstract: Phototherapy of skin diseases such as psoriasis is an effective and safe treatment modality. However, increasing the risk of skin cancer by phototherapy is a serious concern. An increased skin cancer risk occurs after prolonged photochemotherapy (PUVA). In contrast, the role of broadband UVB or narrowband UVB therapy in skin carcinogenesis of humans with psoriasis is less clear. Therefore, we investigated the incidence of skin tumours in a total of 195 psoriasis patients, receiving broadband (n~69) or narrowband (n~126) UVB from 1994 to 2000 with follow-up until 2003. Data were raised from the regional interdisciplinary cancer centre of the University of Tuebingen, Germany and compared with the tumour incidences given for the German population. In this study, with 80% statistical power to detect a 6 – 7-fold increase in skin cancer with broadband UVB and 83% power to detect a 5 – 6-fold increase with narrow band UVB at p~0.05, only one patient developed skin cancer – an in situ melanoma. The tumour occurred within the same year that phototherapy was initiated. Thus, the present study does not provide evidence for an increased skin cancer risk for patients treated with either broadband or narrowband UVB phototherapy Key words: broadband UVB; narrowband UVB; phototherapy; psoriasis; retrospective study; skin cancer risk; ultraviolet light.

181 citations

Journal ArticleDOI
TL;DR: The synthesis and characterization of a red-shifted PTL, L-MAG0460, for the light-gated ionotropic glutamate receptor LiGluR, and visible light excitation and single-wavelength behavior considerably simplify use and should improve utilization in tissue.
Abstract: The use of azobenzene photoswitches has become a dependable method for rapid and exact modulation of biological processes and material science systems. The requirement of ultraviolet light for azobenzene isomerization is not ideal for biological systems due to poor tissue penetration and potentially damaging effects. While modified azobenzene cores with a red-shifted cis-to-trans isomerization have been previously described, they have not yet been incorporated into a powerful method to control protein function: the photoswitchable tethered ligand (PTL) approach. We report the synthesis and characterization of a red-shifted PTL, L-MAG0460, for the light-gated ionotropic glutamate receptor LiGluR. In cultured mammalian cells, the LiGluR+L-MAG0460 system is activated rapidly by illumination with 400-520 nm light to generate a large ionic current. The current rapidly turns off in the dark as the PTL relaxes thermally back to the trans configuration. The visible light excitation and single-wavelength behavior considerably simplify use and should improve utilization in tissue.

181 citations

Journal ArticleDOI
TL;DR: In this article, a van der Waals-based inter-layer heterostructure of a blue phosphorene (BlueP)/BSe interlayer interlayer structure has been shown to be a potential photocatalyst for water splitting under different pH conditions.
Abstract: Constructing van der Waals heterostructures can enhance two-dimensional (2D) materials with desired properties and greatly extend the applications of the original materials. On the basis of density functional theory calculations, we verify that a blue phosphorene (BlueP)/BSe inter-layer heterostructure possesses an indirect gap and intrinsic type-II band alignment. In particular, this heterostructure is found to be a potential photocatalyst for water splitting under different pH conditions and exhibits enhanced optical properties in the visible and ultraviolet light zones. Besides, we confirm that the band gap, band edge position, and optical absorption of the BlueP/BSe heterostructure can be tailored by biaxial strain. And the tensile strain increases the optical absorption significantly over the entire energy range of visible light, which can increase the efficiency of solar energy conversion. Furthermore, we determine that adjusting the number of sublayers is another effective method to modulate the band gaps and band alignments of heterostructures. Our studies provide a promising route to design new BlueP-based vdW heterostructures and explore their potential applications in electronic and optoelectronic devices.

181 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202346
2022181
20211,101
20201,978
20192,639
20182,772