Ultraviolet A

Fluorescent ultraviolet lamps within an apparatus that allows condensation cycles rather than the water spray typical of xenon arc tests have been developed for plastics testing (279). The spectral cutoff wavelength of the lamps used in the apparatus determines the severity of the test. Ultraviolet B (UVB) 313 lamps allow a significant irradiance component below 290 nm, which is normally filtered out by the earth s atmosphere. Ultraviolet A (UVA)... 

Methoxypsoralen (Methoxsalen) [298-81-7] plus ultraviolet A radiation (Vol. 24, Suppl. 7 1987)... 

Combinations of retinoids with ultraviolet A or B radiation (and other drugs). For example, RePUVA-therapy (retinoids and psoralen and UVA combination) is currently one of the most effective regimens for recalcitrant severe psoriasis. 

Tzaneva S, Seeber A, Honigsmann H, Tanew A (2002) A comparison of psoralen plus ultraviolet A... 

Jahnke, L.S., Massive carotenoid accumnlation on Dunaliella bardawil indnced by ultraviolet-A radiation, J. Photochem. Photobiol. B Biol, 48, 68, 1999. 

Moysan, A., Marquis, I., Gaboriau, F., Santus, R., Dubertret, L. and Morliere, P. (1993). Ultraviolet A-induced lipid peroxidation and antioxidant defence systems in cultured skin fibroblasts. J. Invest. Dermatol. 100, 692-698. 

UTP Uridine triphosphate UV Ultraviolet UVA Ultraviolet A UVB Ultraviolet B UVR Ultraviolet irradiation UW University of Wisconsin (preserving solution)... 

Krutmann J. 2000. Ultraviolet A radiation-induced biological effects in human skin relevance for photoaging and photodermatosis. J Dermatol Sci 23 S22-S26. 

Health Issues of Ultraviolet A Sunbeds used for Cosmetic Purposes , Health Physics 61, 285, (1991). 

Reelfs, O., Tyrrell, R. M., and Pourzand, C., Ultraviolet a radiation-induced immediate iron release is a key modulator of the activation of NF-kappaB in human skin fibroblasts, J. Invest. Dermatol. 122, 1440-1447, 2004. 

Nghiem, D. X. et al., Ultraviolet A radiation suppresses an established immune response Implications for sunscreen design, J. Invest. Dermatol. 117, 1193-1199, 2001. 

Q81 An ultrablock sunscreen preparation always has a sun protection factor of 30. Sunscreen preparations protect the skin from the damage associated with ultraviolet A (UVA). 

Persistent photosensitivity developed in eight men after occupational exposure to hot epoxy resin fiimes. The condition was limited to sites contacted by the resin. Small doses of ultraviolet-A light evoked abnormal reactions consisting of erythema, edema, and papules in the clinically involved skin. Positive photopatch tests were observed to epoxy resin in four subjects and to bisphenol A in all subjects. Another study showed that bisphenol A can be released during the thermal decomposition of epoxy resin in the temperature range of 250-350°C. Photosensitizing activity was explained by the formation of ftee radicals during exposure to ultraviolet-B radiation of bisphenol A vapor, to form a semiquinone derivative of bisphenol A ... 

Ultraviolet and infrared absorptions have been reported for an extensive series of l-aryl-5-(2 -dialkylaminovinyl)-lTf-tetrazoles. The 5-vinyl C=C stretch appears at 1624-1641 cm and the ultraviolet A ax (MeCN) was at ca. 300 50 nm depending on substituents <88JPR963>. In some 1,5-disubstituted derivatives the conjugated substituent may be twisted significantly out of the tetrazole... 

Acitretin is most useful for the treatment of severe psoriasis, particularly the pustular and erythrodermic variants. Psoriatic nail changes and arthritis also may respond. Combining the drug with ultraviolet light therapy (Re-UVB, in the case of ultraviolet B radiation, or Re-PUVA, with psoralen plus ultraviolet A radiation) permits the use of lower doses of both acitretin and ultraviolet radiation. Other conditions for which the drug may be especially useful include congenital and acquired hyperkeratotic disorders, such as the ichthyoses and palmoplantar keratodermas, and severe lichen planus. 

Jain, V.K. and Guruprasad, K.N., Differences in the synthesis of anthocyanin in Sorghum bicolor after exposure to ultraviolet-A, blue, red, far-red and white light. Plant Physiol Biochem., 17, 23,... 

In the photoelectric method, the measured average work function is always less than the true since patches of high work function tend to be excluded from the emission process. Thus, the nonuniform distribution of adsorbate on a patch surface may cause a slight discrepancy in the evaluation of A. Experimentally, the photoelectric method has various limitations. Photocurrents of the order of 10 A. must be measured accurately in the region of vo, and for films of work function greater than 5 v., the threshold frequency lies in the far ultraviolet—a practical disadvantage. Furthermore, the method is inapplicable at pressures in excess of 10 mm. Hg because of ionization of the gas by collision. 

Observations Azo intermediates that effectively absorb ultraviolet A (UV-A) radiation... 

Psoralens must be photoactivated by long-wavelength ultraviolet light in the range of 320-400 nm (ultraviolet A [UVA]) to produce a beneficial effect. Psoralens intercalate with DNA and, with subsequent UVA irradiation, cyclobutane adducts are formed with pyrimidine bases. Both monofunctional and bifunctional adducts may be formed, the latter causing interstrand cross-links. These DNA photoproducts may inhibit DNA synthesis. The major long-term risks of psoralen photochemotherapy are cataracts and skin cancer. 

Peak, J.G, Pilas, B., Dudek, E.J. Peak, M.J. (1991) DNA breaks caused by monochromatic 365 nm ultraviolet-A radiation or hydrogen peroxide and their repair in human epithelioid and xeroderma pigmentosum cells. Photochem. Photobiol., 54, 197-203... 

Fig. VII-9. Absorption coefficients of phosgene in the ultraviolet and in the vacuum ultraviolet, (a) Approximate values calculated from the data of Motile and Foo (721) and Heicklen (452). k is given in units of atm " 1 cm 1, base e, 25 C. (b) Absorption coefficients in the 1400 to 1600 A region From Okabe et al. (766). (c) Absorption coefficients in the 1150 to 1400 A region k is given in units of atm" 1 cm"1, base e, 25°C. From Okabe et al. (766). Reprinted by permission. Copyright 1971 by the American Institute of Physics.

Fig. VII-24. Absorption cross sections of chlorine nitrate in the near ultraviolet a is in units of cm2 molec"1, base e, room temperature. Reprinted with permission from F. S. Rowland, J. E. Spencer, and M. J. Molina, J. Phys. Chem. 80, 2711 (1976). Copyright by the American Chemical Society.

Fig. VII-IS. (a) Absorption cross sections of CHjCI in the near ultraviolet. a in units of cm1 moiec, base e, room temperature. From Robbins (837), reprinted by permission. Copyright by the American Geophysical Union. (A) Absorption cross sections of CH,Br in the near ultraviolet, a is in units of cm2 molec 1, base e, room temperature. From Robbins (837), reprinted by permission. Copyright by the American Geophysical Union.

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