Spectro-Temporal Autofluorescence Contrast–Based Imaging for Brain Tumor Margin Detection and Biobanking
Yu Chen, Babak Kateb in Neurophotonics and Brain Mapping, 2017
Ultraviolet (UV) radiation is part of the electromagnetic spectrum, between the visible and x-ray regions, that spans from extreme UV at 10 nm (nanometers, 10−9 m) to visible violet at 400 nm. Most of the UV spectra, extreme to middle UV (10–300 nm), is absorbed by the atmosphere and does not propagate to long distances. UV radiation is used in many applications in black-light activated technologies and serves different purposes at various wavelength bands; near UV 300–400 nm is used in security measures and counterfeit detection, middle UV 200–300 nm used in disinfection devices, and far UV 100–200 nm that is absorbed by oxygen and does not propagate well in air. The middle UV has more potential in damaging tissue and can cause severe damage to DNA (Sinha and Hader 2002). Devices that use this wavelength band exhibit harmful radiation levels and use it to denature proteins to effectively kill bacteria. Excimer lasers often operate in the far UV and are used in the semiconductor industry for photolithography and in medicine for eye surgeries (LASIK), ablating material without heating the tissue.
Physics of sound and light
Ken Myers, Paul Hannah, Marcus Cremonese, Lourens Bester, Phil Bekhor, Attilio Cavezzi, Marianne de Maeseneer, Greg Goodman, David Jenkins, Herman Lee, Adrian Lim, David Mitchell, Nick Morrison, Andrew Nicolaides, Hugo Partsch, Tony Penington, Neil Piller, Stefania Roberts, Greg Seeley, Paul Thibault, Steve Yelland in Manual of Venous and Lymphatic Diseases, 2017
The electromagnetic spectrum (Figure 4.3) consists of light with wavelengths measured in nanometers (nm – one billionth of a meter), ranging from:Gamma rays: < 0.1 nmX-rays: 0.1–10 nmUltraviolet: 10–400 nmVisible: 440–760 nmNear-infrared: 700–1400 nmMid-infrared: 1400–20,000 nmFar-infrared: 15,000-1,000,000 nmMicrowaves and radiowaves: >1,000,000 nm or 1 mm-100 kmLaser can produce light in the range of ultraviolet 160 nm to infrared rays up to 20,000 nm
Light Sources in Photomedicine
Henry W. Lim, Nicholas A. Soter in Clinical Photomedicine, 2018
The mass production of the quartz-jacketed mercury vapor arc lamp led to an increase in ultraviolet phototherapy from the 1920s to the present (2,6–9). By passing an electrical arc through mercury vapor sealed in a silica glass (quartz) envelope, a discontinuous spectrum of characteristic peaks and valleys is produced (Fig. 1). At low temperature and pressure, 90–95% of the radiation produced is a peak at 254 nm. Other peaks produced include 185, 248, and 263 nm within the ultraviolet C (UVC) spectrum; 297, 303, and 313 nm in the UVB range; and 365, 405, 440, 554, and 578 nm in the UVA and visible spectra. Since 185 nm photons are capable of ionizing oxygen to ozone, all mercury vapor lamps must be used in a well-ventilated area. As the temperature and pressure within the lamp are raised, the relative intensities of the peaks shift, with less UVC and more UVB radiation produced. Operating at a low temperature and pressure, the “cold quartz” lamp has been used for its germicidal properties and for acne phototherapy for many years. It is obviously not useful for UVB or UVA phototesting or phototherapy.
UVGD 1.0: a gene-centric database bridging ultraviolet radiation and molecular biology effects in organisms
Published in International Journal of Radiation Biology, 2019
Hao Xu, Yan Wang, Lihong Diao, Xun Wang, Yi Zhang, Jiarun Zhu, Jinying Liu, Jingwen Yao, Zhongyang Liu, Yang Li, Fuchu He, Zhidong Wang, Yuan Liu, Dong Li
Ultraviolet (UV), or ultraviolet radiation, is electromagnetic radiation with a wavelength from 10 to 400 nm. Exposing to ultraviolet for a certain time will trigger some significant molecular biology effects in an organism. Firstly, ultraviolet can directly damage DNA sequences, leading to gene mutations. And accumulation of mutations in proto-oncogenes and tumor suppressor genes could result in abnormal cell proliferation, which can develop into tumorigenesis eventually. Secondly, ultraviolet can depress the immune system, leading to immunosuppression or even tumorigenesis. Thirdly, ultraviolet can affect the molecular components of cells and impact on the life functions of organisms by causing photoreactions and oxidative stress, bringing about consequences such as synthesis of Vitamin D and skin aging.
Advances in phototherapy for psoriasis and atopic dermatitis
Published in Expert Review of Clinical Immunology, 2019
Lajos Kemény, Emese Varga, Zoltan Novak
Ultraviolet light from the sun or artificial light sources exert a profound immunosuppressive effect, that is mediated – at least partly – by inducing apoptotic cell death in activated T cells. The immunosuppressive effects of the UV light in the skin depend on many different variables, such as the wavelengths, the radiation intensity and the treatment dose, the number of treatment sessions and on the optics of the human skin. Ultraviolet radiation can be classified to as UVB radiation, emitting wavelengths in between 280–320 nm, and UVA radiation that contains wavelengths in between 320–400 nm. In general, UVB light has a more profound immunosuppressive effect than UVA light. Psoralen plus UVA light (PUVA) is a form of photochemotherapy. Psoralens are small molecules, that enter cells and intercalate DNA. Esposure of cells to UVA light results in covalent binding of psoralens to the DNA, thereby blocks the proliferion of the cells, and modify their gene expression profile [5].
Prospects of topical protection from ultraviolet radiation exposure: a critical review on the juxtaposition of the benefits and risks involved with the use of chemoprotective agents
Published in Journal of Dermatological Treatment, 2018
Nilutpal Sharma Bora, Bhaskar Mazumder, Pronobesh Chattopadhyay
According to the American Cancer Society (ACS), ultraviolet radiation is divided into three categories, namely; UVA, UVB, and UVC. UVA rays can cause premature aging of skin cells and can damage their DNA (3). Long-term effects of these rays include wrinkles, and are also thought to cause some forms of skin cancers. UVB rays can directly damage the skin cell DNA and are more responsible for sunburns and most skin cancers than any other rays (4). The UVC rays have the most energy than any other ultraviolet rays, but are not accounted for as they don’t get through our atmosphere. It is a matter of relief that the most biologically damaging radiation UVC is filtered out by the ozone layer; however, UVB rays are a matter of concern because these are responsible for causing the adverse effects of the solar ultraviolet radiation (3,4).
Related Knowledge Centers
- Absorption
- Atom
- Chemical Reaction
- DNA
- Fluorescence
- Ionization
- Ionizing Radiation
- X-Ray
- Sunlight
- Blacklight