Studies have also reported that iontophoresis facilitates the transport of lidocaine molecules into the skin under the influence of electric current and can provide topical anesthesia of intact skin within 5 15 min [ 14].
He proposed that the cause of influenza epidemics during winter may be connected to seasonal fluctuations of vitamin D, which is produced in the skin under the influence of solar (or artificial) UV radiation.
The rest is synthesized in the skin under the influence of sunlight.
Sun exposure plays a central role in vitamin D metabolism, as it is formed in the skin under the influence of UV light [ 15- 17].
As vitamin D is synthesized in the skin under the influence of sunlight and the seasonal variance in serum levels of vitamin D is well known, serum samples were collected in the same season, spring of 2011 [ 23].
Sun exposure plays a central role in vitamin D metabolism as vitamin D is formed in the skin under the influence of UV light [ 15], and there is a well-known seasonal variation with lowest levels during the winter [ 16].
Although vitamin D is obtained from diet and dietary supplements, the main source of vitamin D is its production in skin under the influence of solar ultraviolet B radiation.
It is well known that vitamin D, the precursor of the biologically active vitamin D metabolite 1,25-dihydroxyvitamin D [1,25(OH)2D, calcitriol] can be obtained from the diet or synthesized in the skin under the influence of UV-B radiation from 7-dehydrocholesterol (7-DHC).
It is well-known that most (90%) of vitamin D is synthesized in the skin under the influence of ultraviolet sunlight of the sun, and only 10% of vitamin D is obtained from food, mainly salmon, cod fish, and dairy products.
Vitamin D was discovered when it was noted that rachitic children were improved by exposure to sunlight. 1 It was later shown by Holick et al 2 that vitamin D3 is synthesised in the skin under the influence of ultraviolet light.
