نتایج جستجو برای: solar radiation ultraviolet vitamin d

تعداد نتایج: 990323  

H. Mafakheri, K. Khoshgard, M. Kanaani, M. Rezaei,

ABSTRACT Background: Ultraviolet radiation is present in sunlight. If ultraviolet radiation exceeds the limit, it can cause detrimental effects on human health such as skin cancer and cataract. Materials and Methods: In this descriptive cross-sectional study, the level of solar ultraviolet radiation type A (UVA) were measured using UV LOG HAND HELD in Kermanshah city. The intensity of ultravio...

Journal: :Indian journal of experimental biology 2009
Sunil Kumar Shoma Devi Prashasti Misra Priyanka

Aim of this study was to monitor the solar ultraviolet-B intensity and to compare the phototoxic effect of different intensity of natural and artificial ultraviolet-B on human red blood cells in presence of compounds as riboflavin and chloroquine. Photohemolysis of erythrocytes was studied under natural solar radiation and artificial ultraviolet-B radiation of 312 nm. Monitoring of solar ultrav...

2013
Frank Garland William B Grant

The solar ultraviolet-B (UVB)–vitamin D–cancer hypothesis was proposed in 1980 and has been actively investigated since then. The strongest evidence is from ecologic studies that use indices of solar UVB doses with geographic data on cancer incidence and/or mortality rates. Good evidence also comes from observational studies for breast and colorectal cancer incidence as well as survival rates f...

Journal: :Anticancer research 2009
Emanuela Cicarma Alina Carmen Porojnicu Zoya Lagunova Arne Dahlback Asta Juzeniene Johan Moan

Solar radiation is both the main cause of all types of skin cancer, including cutaneous malignant melanoma (CMM), and the main source of vitamin D accompanied by its beneficial effects. The dilemma lies in that increased sun exposure could lead to an increase in skin cancers and yet is necessary for the better prognosis of internal cancers. Solar radiation varies in intensity and spectral compo...

2017
Seyed Aidin Sajedi Fahimeh Abdollahi

Background Insufficient received ultraviolet B radiation (UV) is regarded as the main environmental risk factor (RF) for MS in vitamin D deficiency hypothesis. Nevertheless, geomagnetic disturbance (GMD) has also been proposed as a potential trigger for MS in GMD hypothesis. The aim of this study was to investigate which of these mentioned RF is correlated with long-term ultradecadal MS inciden...

2014
M Yokoya

Introduction Many epidemiologic studies indicate that cancer mortality rate tends to increase at higher latitudes. One proposed hypothesis explaining this geographical gradient is that vitamin D, which is produced after exposure to solar radiation, has anti-carcinogenic effects. However, the association between solar radiation and cancer risk is not fully explained. The Hypothesis A number of r...

Journal: :Postgraduate medical journal 1981
M S Devgun A J Cruickshank B E Johnson C R Paterson

Four commercially available, medium pressure mercury sun lamps were used to assess their effects on promoting vitamin D synthesis in the skin. It was found that all the lamps studied had vitamin D synthesizing spectral wavelengths and caused an increase in the serum concentrations of 25-hydroxyvitamin D. However, the ultraviolet and visible irradiance measurements showed that a considerable pro...

Journal: :Age and ageing 2011
Roman Romero-Ortuno Lisa Cogan Joseph Browne Martin Healy Miriam Catherine Casey Conal Cunningham James Bernard Walsh Rose Anne Kenny

BACKGROUND Ireland is at 53°N, and its population risk of vitamin D deficiency is high. Previous Irish studies suggested a significant seasonality of serum 25-hydroxyvitamin D [25(OH)D] and a beneficial effect of supplementation in raising 25(OH)D levels. However, in Irish older people, little is known about the magnitude of the supplementation effect and whether supplementation affects 25(OH)D...

2017
Jayabal Pandiaraja

Malignant melanoma is one of the most dangerous forms of cutaneous malignancies [1] . It is classified as cutaneous melanoma and non-cutaneous melanoma based on the location of the lesion. Ultraviolet (UV) radiation exposure is a predisposing factor for cutaneous melanoma, although in other forms such as mucous and anorectal malignant melanomas, ultraviolet radiation does not play a significant...

2008
Johan Moan Alina Carmen Porojnicu

When absorbed, a photon of a given energy has the same chemical and biological effect whether it comes from the sun or from an artificial, man-made source like a sun bed. If the spectrum and intensity of a sun bed are the same as those of the sun, the biological effects will be exactly the same. The main difference between radiation from sun and sun beds is that sun beds emit less visible light...

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