نتایج جستجو برای: uv absorption
تعداد نتایج: 195475 فیلتر نتایج به سال:
A variety of animal species utilize the ultraviolet (UV) component of sunlight as their environmental cues, whereas physiological roles of UV photoreception in mammals, especially in human beings, remain open questions. Here we report that mouse neuropsin (OPN5) encoded by the Opn5 gene exhibited an absorption maximum (λmax) at 380 nm when reconstituted with 11-cis-retinal. Upon UV-light illumi...
Background: Sun protection materials have been one of the major concerns in pharmaceutical industry since almost one century ago. Various materials have been found to have such an effect but there are still many unknown substances that have not been discovered.Objective: To introduce a novel mineral-based sun lotion with considerable UV absorption properties compared to commercially available s...
The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245– 415 nm using the technique of laser photolysis with timeresolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post flash spectra were deconvolved to remove contributions to the observed absorption from other re...
The performance of the EPA Federal Equivalent Method (FEM) technique for monitoring ambient concentrations of O3 via ultraviolet absorption (UV) has been evaluated using data from the Mexico City Metropolitan Area field campaign (MCMA-2003). Comparisons of UV O3 monitors with open path Differential Optical Absorption Spectroscopy (DOAS) and open path Fourier Transform Infrared (FTIR) spectrosco...
We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-Ray Observatory. These spectra reveal many narrow absorption lines from the H-like and He-like ions of O, Ne, Mg, Si, S, and Ar as well as Fe xvii-Fe xxi L-shell lines. We have also identified several weak emission lines, mainly...
We present the first grating-resolution X-ray spectra of the Seyfert 1 galaxy NGC 3783, obtained with the High Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory. These spectra reveal many narrow absorption lines from the H-like and He-like ions of O, Ne, Mg, Si, S and Ar, as well as Fe XVII–Fe XXI L-shell lines. We have also identified several weak emission lines, mainly...
Brent Holben NASA Goddard Space Flight Center Greenbelt, Maryland 20771 Abstract. Radiative transfer calculations of UV irradiance from total ozone mapping spectrometer (TOMS) satellite data are frequently overestimated compared to ground-based measurements because of the presence of undetected absorbing aerosols in the planetary boundary layer. To reduce these uncertainties, an aerosol UV abso...
the effects of electromagnetic fields (emfs) radiation at the frequency of 940 mhz on the structure and function of human adult and fetal hemoglobin (hba and hbf) were studied. after extraction and purification of hba and hbf, the oxygen absorption values for exposed and unexposed hba and hbf to emf were compared. the slope of oxygen absorption curve for exposed hba was increased while that for...
To optimize their growth and survival, plants perceive and respond to ultraviolet-B (UV-B) radiation. However, neither the molecular identity of the UV-B photoreceptor nor the photoperception mechanism is known. Here we show that dimers of the UVR8 protein perceive UV-B, probably by a tryptophan-based mechanism. Absorption of UV-B induces instant monomerization of the photoreceptor and interact...
Today octocrylene is one of the most common molecules included in commercially available sunscreens. It provides broadband photoprotection for the skin from incident UV-A and UV-B radiation of the solar spectrum. In order to understand how octocrylene fulfils its role as a sunscreening agent, femtosecond pump-probe transient electronic UV-visible absorption spectroscopy is utilised to investiga...
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