Retention of linoleic acid in carcass lipids of rats fed different levels of essential fatty acids

Rats of an inbred Sprague-Dawley strain were fed purified diets with low (0.3% of total energy), normal (3%) or high (10%) content of essential fatty acids (EFA) for at least three generations. Two 30-days-old rats with similar weights were chosen from one litter. One was killed; weight increase and food consumption of the other rat was measured for 15 days. Total lipid content and fatty acid composition in total lipid and lipid classes were determined in both rats. Seven pairs of rats from each group were treated in the same way. Calculations based an amount of linoleic acid ingested and retained in the carcass lipids showed that 50% of the ingested linoleic acid was retained in the low EFA rats compared to 10–15% in the normal and high EFA rats.     

The sunscreening effect of urocanic acid

Urocanic acid (UCA), present in the stratum corneum, is a major absorber of ultraviolet (UV) radiation and, on UV exposure, is induced to isomerize from the naturally occurring trans-isomer to the cis-isomer. Cis-UCA has been shown to have immunosuppressive properties, while trans-UCA may act as a natural sunscreen due to its UV-absorbing properties. The photoprotective capacity of UCA was investigated in this study. Minimal erythema dose (MED) was determined on normal buttock skin in 36 healthy subjects and the concentration of UCA isomers was measured on the skin adjacent to the test site. On the contralateral buttock. MED was determined 20 min after application of trans-UCA 5% in a cream base. The UCA cream gave a sun protection factor of 1.58. The amount of UCA applied was, however, 20-200 times higher than the amount of UCA found in normal skin, making a sunscreening effect of naturally occurring UCA very low. This was further supported, by a lack of correlation between naturally occurring UCA and the UV sensitivity of each subject determined by the MED.     

Alternatives to Outdoor Daylight Illumination for Photodynamic Therapy—Use of Greenhouses and Artificial Light Sources

Daylight-mediated photodynamic therapy (daylight PDT) is a simple and pain free treatment of actinic keratoses. Weather conditions may not always allow daylight PDT outdoors. We compared the spectrum of five different lamp candidates for indoor “daylight PDT” and investigated their ability to photobleach protoporphyrin IX (PpIX). Furthermore, we measured the amount of PpIX activating daylight available in a glass greenhouse, which can be an alternative when it is uncomfortable for patients to be outdoors. The lamps investigated were: halogen lamps (overhead and slide projector), white light-emitting diode (LED) lamp, red LED panel and lamps used for conventional PDT. Four of the five light sources were able to photobleach PpIX completely. For halogen light and the red LED lamp, 5000 lux could photobleach PpIX whereas 12,000 lux were needed for the white LED lamp. Furthermore, the greenhouse was suitable for daylight PDT since the effect of solar light is lowered only by 25%. In conclusion, we found four of the five light sources and the greenhouse usable for indoor daylight PDT. The greenhouse is beneficial when the weather outside is rainy or windy. Only insignificant ultraviolet B radiation (UVB) radiation passes through the greenhouse glass, so sun protection is not needed.     

Elektronische Archive in virtuellen Organisationen Gestaltung im Spannungsfeld von Kooperation und Konkurrenz

Virtuelle Organisationen stellen ein relativ neues Anwendungsfeld der Informatik dar. Aus den Besonderheiten dieses Organisationstypus ergeben sich neue Gestaltungsaufgaben. In diesem Aufsatz wird anhand einer Fallstudie aus der Stahlindustrie gezeigt, in welch komplexer Weise Kooperation und Konkurrenz in virtuellen Organisationen miteinander verwoben sein kann. Daraus ergeben sich Konsequenzen für die Gestaltung der Zugriffskontrolle auf elektronische Archive, wenn diese für die organisationsübergreifende Kooperation in einer virtuellen Organisation genutzt werden. Basierend auf diesen Erkenntnissen stellt der in der n?chsten Ausgabe des Informatik Spektrum erscheinende zweite Teil des Aufsatzes eine komponentenbasierte Anwendung zur Zugriffskontrolle in virtuellen Organisationen vor.     

Selenium and its interrelatiosn with mercury in wholeblood and hair in an East Greenlandic population

138 Blood samples and 12 hair samples from the district of Angmagssalik, East Greenland, have been analysed for selenium and mercury. It was found that selenium like mercury, was absorbed in accordance with the amount of marine food eaten. The mean blood concentration in the group eating most marine food was 173 and 186 μg Hg/1 for men and women, respectively, while in the group eating the lowest quantity of marine food, the mean values were 86 and 118 μg Hg/1. In blood, the selenium and mercury did not correlate in individuals, but only in groups according to eating habits. On a molar basis, selenium is present in blood in excess as compared to mercury, while the opposite is the case for hair. It is concluded that only part of the selenium interacts with mercury, and that blood, but not hair, reflects present dietary intake. The rich supply of selenium in relation to mercury exposure through the traditional arctic food is probably able to alleviate the hazards from dietary mercury exposure.     

Die Organknappheit

Zusammenfassung  Zur Verringerung der Knappheit an Organen wird die Einführung eines Marktes für menschliche Organe vorgeschlagen. Personen, die ihre Organe verkaufen, und Personen, die ihre Organe lebend spenden, sind medizinisch den gleichen Gefahren ausgesetzt. Der Verkaufserlös bietet für den Abgebenden eine Einkommenssteigerung, die vielfältig genutzt werden kann. Die auf Schwarzmärkten beobachteten negativen Effekte sollen durch eine strikte Überwachung und Regulierung verhindert werden. Der Markt für Organe kann von zwei getrennten Ankaufsorganisationen geprägt werden. Eine Organisation zahlt die Weiterverkaufserlöse der Organe direkt an die Geber aus, eine andere Organisation investiert sie stattdessen in wohltätige Zwecke und gibt so den Gebern die Möglichkeit, ihr Organ aus rein altruistischen Motiven zu spenden. Die Finanzierung des Systems soll durch das öffentliche Gesundheitssystem bzw. die privaten Krankenversicherungen erfolgen.

Geochemical and Process Engineering Challenges for Geothermal Power Generation

Handling of the geothermal fluid, which is typically a complex mixture of salt solution and dissolved gases, is one of the main challenges for designing and operating reliable and efficient geothermal power plants. In the geothermal fluid loop, undesired mineral precipitation and fluid‐material interactions must be prevented and the design and dimensioning of all components must be adapted according to the characteristics of the geothermal fluid. This paper outlines geochemical and process engineering aspects as well as research activities in these fields and introduces the Groß Schönebeck site, which is a central site for geothermal research.     

Artificial Opals as Effect Pigments in Clear‐Coatings

Summary: In this paper, we describe the use of artificial opals from polymer beads as effect pigments in transparent industrial and automotive coatings. For this purpose, we synthesized monodisperse colloids from fluorinated methacrylates by surfactant‐free emulsion polymerization. The fluorinated monomers, in combination with crosslinking, lead to a refractive index contrast, thermal stability, and solvent resistivity necessary for use as effect pigments. After crystallization of the monodisperse polymer beads, crystal flakes with iridescent colors can be obtained. The crystal flakes can act as effect pigments in various transparent industrial and automotive coatings. Due to photonic crystal behavior of effect pigments, color flops up to 100 nm are observed.

Crystal flakes of CS ‐7 as effect pigments in a transparent coating. The diameter of the tube is 5 mm.