88 research outputs found

    SWS observations of IR emission features towards compact HII regions

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    We present ISO Short Wavelength Spectrometer (SWS) grating spectra of six compact HII regions. In addition to strong emission lines from atomic species these spectra display infrared bands attributed to Polycyclic Aromatic Hydrocarbons (PAHs). The continuous spectral coverage of the present observations and the high spectral resolution allow to describe the detailed structure of the emission bands: the 7.7μm band is composed of two bands at 7.6 and 7.8μm, the 6.2 μm band has a long wavelength extension, there is a plateau of emission between 6 and 7μm and a new feature is reported at 11.0μm in addition to the well-known 11.2μm band. These observations also reveal large variations in the relative intensities of the dust bands, in particular between the 7.7 and 8.6μm bands. In one extreme case, the 8.6μm band is stronger than the 7.7μm band. These observations are compared to a mixed population of ionized PAHs, using new laboratory measurements

    Induction of isoprenyl diphosphate synthases, plant hormones and defense signalling genes correlates with traumatic resin duct formation in Norway spruce (Picea abies)

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    Norway spruce (Picea abies) defends itself against herbivores and pathogens by formation of traumatic resin ducts filled with terpenoid-based oleoresin. An important group of enzymes in terpenoid biosynthesis are the short-chain isoprenyl diphosphate synthases which produce geranyl diphosphate (C10), farnesyl diphosphate (C15), and geranylgeranyl diphosphate (C20) as precursors of monoterpenes, sesquiterpenes, and diterpene resin acids, respectively. After treatment with methyl jasmonate (MJ) we investigated the expression of all isoprenyl diphosphate synthase genes characterized to date from Norway spruce and correlated this with formation of traumatic resin ducts and terpene accumulation. Formation of traumatic resin ducts correlated with higher amounts of monoterpenes, sesquiterpenes and diterpene resin acids and an upregulation of isoprenyl diphosphate synthase genes producing geranyl diphosphate or geranylgeranyl diphosphate. Among defense hormones, jasmonate and jasmonate-isoleucine conjugate accumulated to higher levels in trees with extensive traumatic resin duct formation, whereas salicylate did not. Jasmonate and ethylene are likely to both be involved in formation of traumatic resin ducts based on elevated transcripts of genes encoding lipoxygenase and 1-aminocyclopropane-1-carboxylic acid oxidase associated with resin duct formation. Other genes involved in defense signalling in other systems, mitogen-activated protein kinase3 and nonexpressor of pathogenesis-related gene1, were also associated with traumatic resin duct formation. These responses were detected not only at the site of MJ treatment, but also systemically up to 60 cm above the site of treatment on the trunk

    Saturated Fats: A Perspective from Lactation and Milk Composition

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    For recommendations of specific targets for the absolute amount of saturated fat intake, we need to know what dietary intake is most appropriate? Changing agricultural production and processing to lower the relative quantities of macronutrients requires years to accomplish. Changes can have unintended consequences on diets and the health of subsets of the population. Hence, what are the appropriate absolute amounts of saturated fat in our diets? Is the scientific evidence consistent with an optimal intake of zero? If not, is it also possible that a finite intake of saturated fats is beneficial to overall health, at least to a subset of the population? Conclusive evidence from prospective human trials is not available, hence other sources of information must be considered. One approach is to examine the evolution of lactation, and the composition of milks that developed through millennia of natural selective pressure and natural selection processes. Mammalian milks, including human milk, contain 50% of their total fatty acids as saturated fatty acids. The biochemical formation of a single double bond converting a saturated to a monounsaturated fatty acid is a pathway that exists in all eukaryotic organisms and is active within the mammary gland. In the face of selective pressure, mammary lipid synthesis in all mammals continues to release a significant content of saturated fatty acids into milk. Is it possible that evolution of the mammary gland reveals benefits to saturated fatty acids that current recommendations do not consider

    ICAR: endoscopic skull‐base surgery

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