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Specific Absorption (specific + absorption)

Distribution by Scientific Domains
Life Sciences80%

Terms modified by Specific Absorption

  • specific absorption rate
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    Selected Abstracts

    Subjective symptoms among mobile phone users,A consequence of absorption of radiofrequency fields?

    BIOELECTROMAGNETICS, Issue 3 2003
    Jonna Wilén
    Abstract In a previous epidemiological study, where we studied the prevalence of subjective symptoms among mobile phone (MP) users, we found as an interesting side finding that the prevalence of many of the subjective symptoms increased with increasing calling time and number of calls per day. In this extrapolative study, we have selected 2402 people from the epidemiological study who used any of the four most common GSM MP. We used the information about the prevalence of symptoms, calling time per day, and number of calls per day and combined it with measurements of the Specific Absorption Rate (SAR). We defined three volumes in the head and measured the maximum SAR averaged over a cube of 1 g tissue (SAR1g) in each volume. Two new exposure parameters Specific Absorption per Day (SAD) and Specific Absorption per Call (SAC) have been devised and are obtained as combinations of SAR, calling time per day, and number of calls per day, respectively. The results indicates that SAR values >0.5 W/kg may be an important factor for the prevalence of some of the symptoms, especially in combination with long calling times per day. Bioelectromagnetics 24:152,159, 2003. © 2003 Wiley-Liss, Inc. [source]

    Formation and distribution of oxidized fatty acids during deep- and pan-frying of potatoes

    EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 11 2007
    Nick Kalogeropoulos
    Abstract The formation of cis- 9,10-epoxystearate, trans- 9,10-epoxystearate, cis -9,10-epoxyoleate, cis -12,13-epoxyoleate, trans -9,10-epoxyoleate, trans -12,13-epoxyoleate and the co-eluting 9- and 10-ketostearates during eight successive pan- and deep-frying sessions of pre-fried potatoes in five different types of vegetable oils , namely cottonseed oil, sunflower oil, vegetable shortening, palm oil and virgin olive oil , was followed and quantified both in fried oils and in fried potatoes by GC/MS after derivatization to methyl esters. These oxidized fatty acids were present at relatively low concentrations in the fresh oils and pre-fried potatoes while they increased linearly with frying time, reaching up to 1140.8,µg/g in virgin olive oil (VOO) and 186.9,µg/g in potatoes pan-fried in VOO after eight pan-frying sessions, with trans -9,10-epoxystearate predominating in all cases. The formation of polymerized triacylglycerols (PTG) was also quantified in frying oils by size exclusion HPLC. Pan-frying caused higher oxidized fatty acid and PTG formation compared to deep-frying. Epoxyoleates and PTG concentrations were increased after frying in polyunsaturated oils, while epoxystearate and 9- and 10-ketostearate concentrations were increased after frying in monounsaturated oils. No specific absorption of the oxidized fatty acids by the fried potatoes seems to occur. The dietary intake of oxidized fatty acids and PTG by the consumption of fried potatoes was discussed. [source]

    DIEL VARIATIONS IN OPTICAL PROPERTIES OF IMANTONIA ROTUNDA (HAPTOPHYCEAE) AND THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE) EXPOSED TO DIFFERENT IRRADIANCE LEVELS,

    JOURNAL OF PHYCOLOGY, Issue 3 2008
    Sébastien Mas
    Diel variations of cellular optical properties were examined for cultures of the haptophyte Imantonia rotunda N. Reynolds and the diatom Thalassiosira pseudonana (Hust.) Hasle et Heimdal grown under a 14:10 light:dark (L:D) cycle and transferred from 100 ,mol photons · m,2 · s,1 to higher irradiances of 250 and 500 ,mol photons · m,2 · s,1. Cell volume and abundance, phytoplankton absorption coefficients, flow-cytometric light scattering and chl fluorescence, and pigment composition were measured every 2 h over a 24 h period. Results showed that cell division was more synchronous for I. rotunda than for T. pseudonana. Several variables exhibited diel variability with an amplitude >100%, notably mean cell volume for the haptophyte and photoprotective carotenoids for both species, while optical properties such as flow-cytometric scattering and chl a,specific phytoplankton absorption generally showed <50% diel variability. Increased irradiance induced changes in pigments (both species) and mean cell volume (for the diatom) and amplified diel variability for most variables. This increase in amplitude is larger for pigments (factor of 2 or more, notably for cellular photoprotective carotenoid content in I. rotunda and for photosynthetic pigments in T. pseudonana) than for optical properties (a factor of 1.5 for chl a,specific absorption, at 440 nm, in I. rotunda and a factor of 2 for the absorption cross-section and the chl a,specific scattering in T. pseudonana). Consequently, diel changes in optical properties and pigmentation associated with the L:D cycle and amplified by concurrent changes in irradiance likely contribute significantly to the variability in optical properties observed in biooptical field studies. [source]

    Strong signature of the active Sun in 100 years of terrestrial insolation data

    ANNALEN DER PHYSIK, Issue 6 2010
    W. Weber
    Abstract Terrestrial solar irradiance data of the Smithsonian Astrophysical Observatory from 1905 to 1954 and of Mauna Loa Observatory from 1958 to 2008 are analyzed. The analysis shows that, with changing solar activity, the atmosphere modifies the solar irradiance on the percentage level, in all likelihood via cosmic ray intensity variations produced by the active sun. The analysis strongly suggests that cosmic rays cause a large part of the atmospheric aerosols. These aerosols show specific absorption and scattering properties due to an inner structure of hydrated ionic centers, most probably of O2 - and O2+ produced by the cosmic rays. [source]