نتایج جستجو برای: ultraviolet protection
تعداد نتایج: 219057 فیلتر نتایج به سال:
Solar radiation is well known to damage human skin, for example by causing premature skin ageing (i.e. photoageing). We have recently learned that this damage does not result from ultraviolet (UV) radiation alone, but also from longer wavelengths, in particular near-infrared radiation (IRA radiation, 760-1,440 nm). IRA radiation accounts for more than one third of the solar energy that reaches ...
Photodegradation causes a steady loss of the useful physical, mechanical and optical properties of materials, necessitating their replacement over time. Because UV (Ultraviolet) light is most harmful in this regard, many materials now contain UV-protective additives. However, these additives are not always effective and durable, can be expensive, and their natural extraction or synthetic produc...
The present study was undertaken to study the sunscreen activity of herbal formulation. There is no evidence of the sun protection factor (SPF) studies on essential oil of Calendula flowers (Calendula officinalis L., Asteraceae). The study investigates the in vitro SPF by ultraviolet specrtophotometry method of Calendula flower oil in a cream formulation. Calendula oil was isolated by Clavenger...
BACKGROUND Solar ultraviolet (UV) radiation causes various deleterious effects, and UV blockage is recommended for avoiding sunburn. Nanosized titanium dioxide and zinc oxide offer effective protection and enhance cosmetic appearance but entail health concerns regarding their photocatalytic activity, which generates reactive oxygen species. These concerns are absent in nanodiamonds (NDs). Among...
Many bacterial plasmids have the effect of increasing the ultraviolet (u.v.) resistance of host cells that harbour them, apparently by an error-prone repair mechanism that leads to a high level of mutation amongst the survivors. These plasmid systems are apparently analogues of the Escherichia coli umuD/C operon, which is absolutely required in this organism for mutation induced by u.v. light a...
Sun exposure is today well recognized as having an adverse effect on human skin. Part of sun radiation, ultraviolet radiation A (UVA) and B (UVB), can modify skin structures and induce short-term skin changes (sunburn, tanning, hyperkeratinization, brown spots) and long-term skin damages (accelerated skin aging and skin cancers). Protection against both UVA and UVB is very important, therefore ...
BACKGROUND The melanoma incidence has increased over recent decades. Educational campaigns aim to encourage protection from the sun and early detection of melanoma. METHODS During a campaign in Switzerland, information on risk factors, sun protection and melanoma prevention was distributed. 10987 people completed a questionnaire regarding risk factors, and 2746 people were examined by a derma...
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