However, free radicals should by no means be considered as being exclusively destructive. On the contrary, processes such as energy metabolism (in the respiratory chain) and the defence of neutrophilic granulocytes against pathogens and foreign bodies depend on the formation of free radicals.
For this reason alone, it has to be expected that a supply of antioxidants may also cause considerable undesired effects to the skin and the organism. In addition, under certain conditions, some anti-oxidants can also exhibit a pro-oxidant mechanism of action, e.g. ß-carotene or vitamin C, with the question "When is an antioxidant not an antioxidant?"A Letter to the Editor, just published on September 3rd, 2008, in the interdisciplinary medical e-Journal "GMS German Medical Science" of the Association of the Scientific Medical Societies in Germany (AWMF) , explicitly describes the ambivalence of antioxidants with their two sides: a desired and an undesired side.
In a large-scale, multicenter, double-blind and placebo-controlled clinical trial on prevention, 864 persons, whose colon polyps had been removed, received 25 mg of ß-carotene or placebo combined with 1000 mg vitamin C + 400 mg vitamin E or placebo on a daily basis. After four years, the following observations could be made concerning supplementation of ß-carotene and the development of colon polyps: pronounced reduction of the risk for non-smokers and those abstaining from alcohol; slightly increased risk for smokers or alcohol consumers; a doubling of the risk for people who smoke cigarettes and consume more than one alcoholic beverage per day.
Further clinical studies showed that ß-carotene supplementation caused no change in the incidence of non-melanoma skin cancer. After a ß-carotene supplemented diet even a significant exacerbation of the UV-carcinogenesis occurred. A photoprotective effect was not achieved.The artificial supply of antioxidants into the human skin poses further questions. In everyday life, on holidays or at work, large amounts of optical radiation can penetrate into the skin and modify the effects of antioxidants. It has been known for a long time that large quantities of free radicals can be generated in human skin as a result of UV irradiation.
So far, no adequate randomised and placebo-controlled multicenter studies or even meta-analyses have emerged which can shed light on the question of whether antioxidants applied in or on the skin can alter phenomena such as ageing or carcinogenesis of the skin in an unfavourable or favourable sense. We still do not know how UV, visible light and infrared or portions or combinations of these may act on modified concentrations of various antioxidants and on their components in the skin. This is a considerable challenge to the field of dermatological research. Or, to quote H. S. Black: "At present, beta-carotene use as a dietary supplement for photoprotection should be approached cautiously".Publication:
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16.05.2018 | Martin-Luther-Universität Halle-Wittenberg
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
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A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
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At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
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There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
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