INDUCTION OF FREE RADICALS IN DNA BY PROFLAVINE AND VISIBLE LIGHT: INFLUENCE OF OXYGEN AND IONIC STRENGTH

1974 ◽  
Vol 20 (5) ◽  
pp. 433-439 ◽  
Author(s):  
Albert Vorst
Keyword(s):  
Free Radicals ◽  
Ionic Strength ◽  
Visible Light

scholarly journals Antiviral Coatings as Continuously Active Disinfectants

2021 ◽  
Author(s):  
Luisa A. Ikner ◽  
Charles P. Gerba
Keyword(s):  
Titanium Dioxide ◽  
Free Radicals ◽  
Nucleic Acids ◽  
Visible Light ◽  
Quaternary Ammonium ◽  
Uv Light ◽  
Virus Transmission ◽  
Antimicrobial Surfaces ◽  
Bacteria And Fungi ◽  
Growth Of Bacteria

Antimicrobial surfaces and coatings have been available for many decades and have largely been designed to kill or prevent the growth of bacteria and fungi. Antiviral coatings have become of particular interest more recently during the COVID-19 pandemic as they are designed to act as continuously active disinfectants. The most studied antiviral coatings have been metal-based or are comprised of silane quaternary ammonium formulations. Copper and silver interact directly with proteins and nucleic acids, and influence the production of reactive free radicals. Titanium dioxide acts as a photocatalyst in the presence of water and oxygen to produce free radicals in the presence of UV light or visible light when alloyed with copper or silver. Silane quaternary ammonium formulations can be applied to surfaces using sprays or wipes, and are particularly effective against enveloped viruses. Continuously active disinfectants offer an extra barrier against fomite-mediated transmission of respiratory and enteric viruses to reduce exposure between routine disinfection and cleaning events. To take advantage of this technology, testing methods need to be standardized and the benefits quantified in terms of reduction of virus transmission.

Utilization Phase Transition Component Method to Prepare Specially Functionalized Nanoemulsion by Adding Resveratrol/Phenethyl Resorcinol Mixed Active Components and Application in Free Radicals Removal

2020 ◽  
Vol 20 (12) ◽  
pp. 7769-7774
Author(s):  
Wenwen Liu ◽  
Songzhu Cui ◽  
Jianhua Ji ◽  
Dejun Sun ◽  
Tao Wu
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Ionic Strength ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Mass Ratio ◽  
Hydrogen Binding ◽  
Active Components ◽  
Hydrophobic Binding ◽  
Radical Scavenging Ability

To explore the possibility of using a specially functionalized nanoemulsion for the removal of free radical, resveratrol and phenethyl resorcinol were employed to form resveratrol/phenethyl resorcinol mixed active components, and the removal efficiency of free radicals was evaluated. Original nanoemulsion and specially functionalized-nanoemulsion were characterized by DLS and EPR. The free radical scavenging ability of the mixed active components of resveratrol/phenethyl resorcinol was determined as a function of the mass ratio of resveratrol to phenethyl resorcinol, temperature, and ionic strength. In the results, the removal of free radicals by the resveratrol/phenethyl resorcinol nanoemulsion system was found to be more effective than the nanoemulsion alone. At a higher resveratrol ratio, more than 68% of free radicals could be removed. The efficiency was also found to increase with rising temperature. However, efficiency decreased with the increase in ionic strength. In conclusion, compared with conventional nanoemulsion, the combined utilization of nanoemulsion and the mixed active components of resveratrol/phenethyl resorcinol achieved better results for the removal of free radicals because of synergistic effect between nanoemulsion droplets and the mixed active components of resveratrol/phenethyl resorcinol, involving hydrophobic binding, hydrogen binding, and partitioning.

scholarly journals Ultraviolet radiation and melanogenesis

2004 ◽  
Vol 12 (4) ◽  
pp. 203-205 ◽  
Author(s):  
Milenko Stanojevic ◽  
Zorica Stanojevic ◽  
Dragan Jovanovic ◽  
Milena Stojiljkovic
Keyword(s):  
Free Radicals ◽  
Visible Light ◽  
Uv Radiation ◽  
Infrared Radiation ◽  
Biological Effects ◽  
Radiation Energy ◽  
Light Radiation ◽  
Melanin Synthesis ◽  
Protection Mechanisms

Light radiation is a part of the electromagnetic radiation, and it consists of the ultraviolet (UV) radiation, visible light, and infrared radiation. UV radiation energy is absorbed in the form of photons in biomolecules (chromophores) and induces various cellular reactions, out of which photochemical and photosensitizing are the most significant. In contact with the skin UV radiation incites protection mechanisms: the most important are stratum corneum thickening and melanin synthesis (melanogenesis). Basic role of melanin is absorption and scattering of UV rays and neutralization of free radicals. In this review physical characteristics of UV radiation, its biological effects, and relation to melanogenesis and carcinogenesis are discussed.

scholarly journals Nitroxide destruction and flavin-photosensitized damage in inner mitochondrial membranes

1982 ◽  
Vol 60 (12) ◽  
pp. 1452-1462 ◽  
Author(s):  
Rolf Joachim Mehlhorn ◽  
Lester Packer
Keyword(s):  
Lipid Peroxidation ◽  
Absorption Spectrum ◽  
Free Radicals ◽  
Visible Light ◽  
Action Spectrum ◽  
Mitochondrial Membranes ◽  
Paramagnetic Absorption ◽  
Electron Reduction ◽  
Succinate Oxidase ◽  
Loss Rates

Nitroxide free radicals lost their paramagnetic absorption spectrum when they were illuminated with visible light in aged but not freshly isolated inner mitochondrial membranes (SMP's). The action spectrum of spin loss rates coincided with a flavin absorption spectrum. Spin loss consisted of one-electron reduction and "destruction", the latter being defined as spin loss that cannot be reversed by ferricyanide oxidation. By placing SMP's in gas permeable tubing and illuminating alternately under nitrogen and air, it was possible to discriminate qualitatively between spin reduction and destruction. Aerobic spin loss consisted entirely of destruction. When aged SMP's were centrifuged, spin loss was observed in supernatants but not pellets. Flavin fluorescence was observed in the supernatants, suggesting that free flavins catalyzed spin loss. However, addition of exogenous flavins to fresh SMP's did not cause spin loss; hence some other factor was required to cause nitroxide destruction. This factor accumulates during either aerobic or anaerobic aging of SMP's and may be present in mitochondria. Supernatants of aged SMP's, when added to freshly isolated SMP's, induced rapid nitroxide destruction, slightly accelerated photodamage to succinate oxidase, and considerably increased photo-induced lipid peroxidation.

Photocatalytic oxidation of arylalcohols to aromatic aldehydes promoted by hydroxyl radicals over a CoP/CdS photocatalyst in water with hydrogen evolution

2018 ◽  
Vol 8 (10) ◽  
pp. 2540-2545 ◽  
Author(s):  
Yong Xu ◽  
Ling-Zhen Zeng ◽  
Zi-Cheng Fu ◽  
Cong Li ◽  
Zhi Yang ◽  
...  
Keyword(s):  
Free Radicals ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydroxyl Radicals ◽  
Photocatalytic Oxidation ◽  
Aromatic Aldehydes ◽  
Hydroxyl Free Radicals

Hydroxyl free radicals generated by visible-light-catalyzed water splitting over CoP/CdS drive the oxidation of arylalcohols with hydrogen evolution.

Detection and Identification of Free Radicals Generated by UV and Visible Light inEx VivoHuman Skin

2009 ◽  
Vol 31 (5) ◽  
pp. 402-402 ◽  
Author(s):  
Leonhard Zastrow ◽  
Norbert Groth ◽  
Frank Klein ◽  
Dieter Kockott ◽  
Jürgen Lademann ◽  
...  
Keyword(s):  
Free Radicals ◽  
Visible Light ◽  
Detection And Identification
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