Effectiveness of UVAs

Ortwerth BJ, Chemoganskiy V Mossine VV Olesen PR. The effect of UVA light on the anaerobic oxidation of ascorbic acid and the glycation of proteins. Invest Ophthalmol Vis Sci 2003 44 3094-3102. 

O. Holm-Hansen (1997). Short- and long-term effects of UVA and UVB on marine phytoplankton productivity. Photochem. PhotobioL, 65,266-268. 

C.J. Bertling, F. Lin, A.W. Girotti (1996). Role of hydrogen peroxide in the cytotoxic effects of UVA/B radiation on mammalian cells. Photochem. PhotobioL, 64,137-142. 

The effectivity of UVAs will also depend on the influence of intensity on the degradation rate. If the degradation rate is linear in light intensity a 50% reduction will lead to a doubling of the lifetime. However, when the stability depend on the square root of the intensity a 50% light reduction only lead to a 30% increase in lifetime. 

Photobiology is the study of the effect of UVA or UVB, visible, and infrared radiation on living systems.12 The first... 

No case reports of drug or supplement interactions were identified. Several reference texts indicate that concomitant use of uva-ursi with medications that can acidify the urine may result in a decrease of effectiveness of uva-ursi (Bradley 1992 ESCOP 2003 Weiss and Meuss 2001). The acidity of cranberry, another botanical commonly use to treat urinary tract infections, is often cited as a reason to avoid taking... 

No effects of uva-ursi on isolated rat or guinea pig uter-uses were observed after application of 1 to 2 mg of crude drug per square centimeter (Shipochliev 1981). 

TLC-densitometric method was developed to monitor the effect of UVA radiation on fluoxetine stability in solid phase with and without the presence of selected metal ions [12]. 

According to Lambert-Beer s law light absorption is a function of the extinction coefficient of the absorber, its concentration, and the path length. As a result the effect of UVAs to protect thin articles or against surface degradation is limited [139],... 

The effect of UVA radiation on graphene-containing (1 and 2 wt%) UV-cured epoxy nanocomposites were studied [270]. It was found that graphene dispersed into the epoxy matrix granted an increased bearing-load capacity and, simultaneously, drastically reduced the photooxidative degradation. 

A cooperative interaction between two or more antioxidants (or antioxidant function) that leads to an overall antioxidant effect greater than the sum of the individual effects of each antioxidant is referred to as synergism. Synergism can be achieved in different ways. It may arise from the combined action of two chemically similar antioxidants, e.g., two hindered phenols (homosynergism), or when two different antioxidant functions are present in the same molecule (autosynergism) the latter is exemplified by many commercial antioxidants (e.g., Irgastab 2002, AO 29 Table lb), which have CB and UVA activity. 

Punnonen, K., Jansen, C.T., Puntala, A. and Ahotupa. M. (1991b). Effects of in vitro UVA irradiation and PUVA treatment on membrane fatty acids and activities of anti-oxidant enzymes in human keratinocytes. J. Invest. Dermatol. 96, 255-259. 

There is a bath PUVA and an oral PUVA. Bath PUVA therapies involve soaking in a bath of psoralens liquid for 15 minutes prior to UVA treatment. Oral PUVA involves taking an oral psoralens capsule the day prior to a UVA treatment. Oral psoralens such as methoxsalen cause nausea in many patients. Other adverse effects of PUVA include photosensitivity, which necessitates the use of eye protection and UVA-blocking sunscreen for 24 hours after a PUVA treatment macular melanosis at exposed sites (PUVA lentigines) and increased risk of skin cancers, especially squamous cell carcinoma.21... 

Arita, S., S. Ando, H. Hosoda et al. 2005. Acceleration effect of sulfides on photodegradation of carotenoids by UVA irradiation. Biosci. Biotechnol. Biochem. 69 1786-1789. 

Table VII. Synergistic Effect of Acid and TMPTA as Additives in Grafting Styrene to Polyethylene Film Initiated by UVa...

Table XII. Effect of Organic Additives (Urea, Silanes, Fluorinated Alkyl esters) on Grafting of Styrene to Polypropylene Initiated by UVa...

For cells that occur under layers or inside colonies of scytonemin-producing taxa, the attentuation of UVA may be even more effective. The umbrella -function of scytonemin produced by surface layers of Lyngbya aestuarii in microbial mats for other cyanobacteria living underneath has already been described (Sect. 13.3.1) (Karsten et al. 1998a). 

The cytotoxic and photocytotoxic effects of two water-soluble fullerene derivatives, a dendritic CL mono-adduct and the malonic acid CL tris-adduct were tested on Jurkat cells when irradiated with UVA or UVB light (Rancan et al., 2002). The cell death was mainly caused by membrane damage and it was UV dose-dependent. Tris-malonic acid fullerene was found to be more phototoxic than the dendritic derivative. This result is in contrast to the singlet oxygen quantum yields determined for the two compounds. 

PUVA is most useful for the treatment of severe psoriasis. Early (patch and plaque) stage cutaneous T-cell lymphoma (CTCL) also responds to PUVA therapy. In addition, patients in advanced stages of CTCL have been treated with a modification of PUVA known as extracorporeal photopheresis. In this therapy, blood from a CTCL patient who has taken psoralen is exposed to UVA light and returned to the patient. Lymphocytes are altered or destroyed by the treatment, and theoretically, the return of these abnormal cells triggers an immune response directed against certain lymphocyte surface antigens. The effectiveness of this modality appears to be variable. 

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