Objective: To investigate whether sunscreens provide optimal protection by exhibiting a uniform spectral absorption profile throughout the ultraviolet spectrum or by having a spectral profile in which absorption in the UVB waveband is greater than in the UVA region.
Methods: A sunscreen with a flat spectral absorption profile was compared with one of the same SPF in which the SPF to UVA protection was in the ratio of 3 : 1 in terms of protecting against erythema and chronic effects with different action spectra, as well as the total UV burden to the skin.
Results: A sunscreen with spectral profile in which absorption in the UVB waveband is greater than in the UVA region confers no benefit in terms of erythema (and endpoints with similar action spectra) than a sunscreen with the same SPF that exhibits uniform absorption at all wavelengths throughout the UV spectrum. More importantly, the '3 : 1 profile' offers inferior protection when endpoints with other action spectra are considered, as well as resulting in a total UV burden to the skin that is about 5 times higher than sunscreen products showing a flat spectral absorption profile.
Conclusion: It may be tempting to believe that it is beneficial to increase the absorption of sunscreens in the UVB region relative to the UVA to reflect the fact that skin damage is associated more with UVB than UVA exposure. However, this belief is a fallacy and consumers are best served with sunscreens in which the spectral protection profile is uniform at all wavelengths throughout the UV spectrum.
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http://dx.doi.org/10.1111/ics.12353 | DOI Listing |
Anal Methods
November 2017
Centre de Recherche sur la Conservation (CRC), MNHN, Sorbonne-Universités CNRS, MCC, USR 3224, CP21, 36 rue Geoffroy Saint Hilaire, 75005 Paris, France.
Reflectance spectral imaging is a powerful tool for the non-invasive study of cultural heritage objects. Particular visible to short wave infrared (400-2500 nm) spectral features are linked to compositional information. Spectral images can hence be used to generate useful chemical maps.
View Article and Find Full Text PDFLangmuir
January 2025
College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin 150040, China.
Solar-driven interfacial evaporation technology is regarded as a promising strategy for global freshwater shortage owing to its green and sustainable desalination process. Graphene aerogel (GA) is widely utilized in the design of solar-driven steam generation systems due to its excellent photothermal conversion efficiency and broad spectral absorption. Given the significant impact of hydrophilicity and thermal insulation on the performance of evaporators, nitrogen doping in the graphene structure not only effectively enhances its wettability but also allows for moderate tuning of its thermal conductivity, thereby optimizing the overall performance of the evaporator.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Physics Department, Khalifa University, Abu-Dhabi, United Arab Emirates.
The spectrum of carbon monoxide is important for astrophysical media, such as planetary atmospheres, interstellar space, exoplanetary and stellar atmospheres; it also important in plasma physics, laser physics and combustion. Interpreting its spectral signature requires a deep and thorough understanding of its absorption and emission properties. A new accurate spectroscopic model for the ground and electronically-excited states of the CO molecule computed at the aug-cc-pV5Z CASSCF/MRCI+Q level is reported.
View Article and Find Full Text PDFWe study resonance redistribution mechanisms inside a hot vapor cell. This is achieved by pumping cesium atoms on the 6S→6P resonance and subsequently probing the velocity distribution of the 6P population by a linear absorption experiment on the 6P→16S or 6P→15D transitions at 514 nm and 512 nm, respectively. We demonstrate that despite the existence of thermalization processes, traces of the initial velocity selection, imposed by the pump, survive in hyperfine levels of the intermediate (6P) state.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, P. R. China.
Dark current density, a critical parameter in perovskite photodetectors (PPDs), largely depends on the quality of the perovskite film. Herein, we introduce a new small molecule in antisolvent strategy to enhance perovskite film quality during the crystallization of Cs(FAMA)Pb(IBr). COTIC-4Cl, an N-type narrow bandgap nonfullerene small molecule with specific functional group, could strongly bind to the uncoordinated Pb in the perovskite with assistance of antisolvent, enabling rapid supersaturation of perovskite solution and form dense structures under low-temperature annealing.
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