90 research outputs found
Identificação de queimaduras térmicas como injúria relacionada ao trabalho de soldadores
Photostability of commercial sunscreens upon sun exposure and irradiation by ultraviolet lamps
BACKGROUND: Sunscreens are being widely used to reduce exposure to harmful ultraviolet (UV) radiation. The fact that some sunscreens are photounstable has been known for many years. Since the UV-absorbing ingredients of sunscreens may be photounstable, especially in the long wavelength region, it is of great interest to determine their degradation during exposure to UV radiation. Our aim was to investigate the photostability of seven commercial sunscreen products after natural UV exposure (UVnat) and artificial UV exposure (UVart). METHODS: Seven commercial sunscreens were studied with absorption spectroscopy. Sunscreen product, 0.5 mg/cm(2), was placed between plates of silica. The area under the curve (AUC) in the spectrum was calculated for UVA (320–400 nm), UVA1 (340–400 nm), UVA2 (320–340 nm) and UVB (290–320 nm) before (AUC(before)) and after (AUC(after)) UVart (980 kJ/m(2 )UVA and 12 kJ/m(2 )of UVB) and before and after UVnat. If theAUC Index (AUCI), defined as AUCI = AUC(after)/AUC(before), was > 0.80, the sunscreen was considered photostable. RESULTS: Three sunscreens were unstable after 90 min of UVnat; in the UVA range the AUCI was between 0.41 and 0.76. In the UVB range one of these sunscreens was unstable with an AUCI of 0.75 after 90 min. Three sunscreens were photostable after 120 min of UVnat; in the UVA range the AUCI was between 0.85 and 0.99 and in the UVB range between 0.92 and 1.0. One sunscreen showed in the UVA range an AUCI of 0.87 after UVnat but an AUCI of 0.72 after UVart. Five of the sunscreens were stable in the UVB region. CONCLUSION: The present study shows that several sunscreens are photounstable in the UVA range after UVnat and UVart. There is a need for a standardized method to measure photostability, and the photostability should be marked on the sunscreen product
Clinical assessment of the efficacy of photodynamic therapy in the treatment of oral lichen planus
The susceptibility of Streptococcus mutans to antibacterial photodynamic therapy: a comparison of two different photosensitizers and light sources
Influence of Formulation Factors on PpIX Production and Photodynamic Action of Novel ALA-loaded Microparticles
The influence of photodynamic therapy with 5-aminolevulinic acid on senescent skin cancer cells
Heterogeneity of fibrillin‐rich microfibrils extracted from human skin of diverse ethnicity
Microneedle pre-treatment of human skin improves 5-aminolevulininc acid (ALA)- and 5-aminolevulinic acid methyl ester (MAL)-induced PpIX production for topical photodynamic therapy without increase in pain or erythema.
Prevention of urinary tract infections with vitamin D supplementation 20,000 IU per week for five years. Results from an RCT including 511 subjects
Supramolecular nanoscale assemblies for cancer diagnosis and therapy
Nanocarriers based on polymers, metals and lipids have been extensively developed for cancer therapy and diagnosis due to their ability to enhance drug accumulation in cancer cells and decrease undesired drug toxicity in healthy tissues. Overcoming multidrug resistance by designing proper drug nanocarriers will improve outcome of existing oncologic treatments such as chemotherapy and radiotherapy. In this article the relation between physicochemical properties and capacity of a nanosystem to deliver therapeutic agents into pathological sites is discussed. Most promising examples of drug delivery systems are reviewed, and, in particular, the design of a carbohydrate based matrix with entrapped gold nanoparticles is highlighted
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