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  • 1. Boettcher, Thomas
    et al.
    Huber, Liliane
    Le Corre, Lucille
    Leitner, Johannes
    McCarthy, David
    Nilsson, Ricky
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för astronomi.
    Teixeira, Carlos
    Vaquer Araujo, Sergi
    Wilson, Rebecca C.
    Adjali, Fatah
    Altenburg, Martin
    Briani, Giacomo
    Buchas, Peter
    Le Postollec, Aurelie
    Meier, Teresa
    The HADES mission concept: astrobiological survey of Jupiter's icy moon Europa2009Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 8, nr 4, s. 321-329Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The HADES Europa mission concept aims to provide a framework for an astrobiological in-depth investigation of the Jupiter moon Europa, relying on existing technologies and feasibility. This mission study proposes a system consisting of an orbiter, lander and cryobot as a platform for detailed exploration of Europa. While the orbiter will investigate the presence of a liquid ocean and characterize Europa's internal structure, the lander will survey local dynamics of the ice layer and the surface environment. The lander releases a cryobot, that melts into the ice, will sample the pristine subsurface and is expected to provide data on organic and gaseous content and putative bio-signatures. In summary, we present the scientific objectives for an astrobiological investigation of Europa, resulting in a mission concept with a detailed evaluation of scientific instrumentation, mission sequences, basic design of the spacecraft, technology needs and cost estimations.

  • 2. de Souza, Claudio M. D.
    et al.
    Carneiro, Cristine E. A.
    Bau, Joao Paulo T.
    da Costa, Antonio C. S.
    Ivashita, Flavio F.
    Paesano, Andrea, Jr.
    di Mauro, Eduardo
    de Santana, Henrique
    Holm, Nils G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Neubeck, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Zaia, Cassia T. B. V.
    Zaia, Dimas A. M.
    Interaction of forsterite-91 with distilled water and artificial seawater: a prebiotic chemistry experiment2013Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 12, nr 2, s. 135-143Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pH(PZC) decreased and the pH(IEP) increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not + II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM-EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch Types (FTT) reactions in hydrothermal vent systems. X-ray diffractograms of the original forsterite-91 also showed peaks arising from zeolites and clinochlore. After the samples were treated with artificial seawater, X-ray diffractograms showed the dissolution of zeolite. Experiments should be performed in the natural environment to verify the potential for zeolites to act as a catalyst in hydrothermal vents.

  • 3.
    Larsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    H-3(+): the initiator of interstellar chemistry2008Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 7, nr 04-mar, s. 237-241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Second only to H-2, protonated molecular hydrogen, H-3(+), is the most abundantly produced interstellar molecule. Owing to its high reactivity and acidity, it plays the pivotal role in initiating interstellar chemical reactions, something which also reduces its steady-state concentration. Interstellar H-3(+) is not only destroyed in chemical reactions but also in dissociative recombination with electrons. The rate constant and mechanism of recombination have long been controversial, but great advances have been made during recent years, with the important consequence that the cosmic ray ionization rate in diffuse Clouds is now believed to be higher by an order of magnitude than previously assumed.

  • 4.
    Lindgren, Paula
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Ivarsson, Magnus
    Naturhistoriska riksmuséet.
    Neubeck, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Broman, Curt
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Henkel, Herbert
    Kungliga tekniska högskolan.
    Holm, Nils
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Putative fossil life in a hydrothermal system of the Dellen impact structure, Sweden2010Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 9, nr 3, s. 137-146Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The role of muscarinic acetylcholine receptors (mAChRs) in regulating glucose uptake in L6 skeletal muscle cells was investigated. [H-3]-2-Deoxyglucose uptake was increased in differentiated L6 cells by insulin, acetylcholine, oxotremorine-M and carbachol. mAChR-mediated glucose uptake was inhibited by the AMPK inhibitor Compound C. Whole cell radioligand binding using [H-3]-N-methyl scopolamine chloride identified mAChRs in differentiated but not undifferentiated L6 cells and M-3 mAChR mRNA was detected only in differentiated cells. M-3 mAChRs are Gq-coupled, and cholinergic stimulation by the rnAChR agonists acetylcholine, oxotremorine-M and carbachol increased Ca2+ in differentiated but not undifferentiated L6 cells. This was due to muscarinic but not nicotinic activation as responses were antagonised by the muscarinic antagonist atropine but not the nicotinic antagonist tubocurarine. Western blotting showed that both carbachol and the AMPK activator AICAR increased phosphorylation of the AMPK alpha subunit at Thr172, with responses to carbachol blocked by Compound C and the CaMKK inhibitor STO609 but not by the PI3K inhibitor wortmannin. AICAR-stimulated AMPK phosphorylation was not sensitive to STO-609, confirming that this compound inhibits CaMKK but not the classical AMPK kinase LKB1. The TAK1 inhibitor (5Z)-7-oxozeaenol and the G(i) inhibitor pertussis toxin both failed to block AMPK phosphorylation in response to carbachol. Using CHO-K1 cells stably expressing each of the mAChR subtypes (M-1-M-4), it was determined that only the M-1 and M-3 mAChRs phosphorylate AMPK, confirming a G(q)-dependent mechanism. This study demonstrates that activation of M-3 mAChRs in L6 skeletal muscle cells stimulates glucose uptake via a CaMKK-AMPK-dependent mechanism, independent of the insulin-stimulated pathway.

  • 5.
    Neubeck, Anna
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Tulej, Marek
    Ivarsson, Magnus
    Broman, Curt
    Riedo, Andreas
    McMahon, Sean
    Wurz, Peter
    Bengtson, Stefan
    Mineralogical determination in situ of a highly heterogeneous material using a miniaturized laser ablation mass spectrometer with high spatial resolution2016Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 15, nr 2, s. 133-146Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Techniques enabling in situ elemental and mineralogical analysis on extraterrestrial planets are strongly required for upcoming missions and are being continuously developed. There is ample need for quantitative and high-sensitivity analysis of elemental as well as isotopic composition of heterogeneous materials. Here we present in situ spatial and depth elemental profiles of a heterogeneous rock sample on a depth-scale of nanometres using a miniaturized laser ablation mass spectrometer (LMS) designed for planetary space missions. We show that the LMS spectra alone could provide highly detailed compositional, three-dimensional information and oxidation properties of a natural, heterogeneous rock sample. We also show that a combination of the LMS and Raman spectroscopy provide comprehensive mineralogical details of the investigated sample. These findings are of great importance for future space missions where quick, in situ determination of the mineralogy could play a role in the process of selecting a suitable spot for drilling.

  • 6.
    Schmidt, Henning
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Johansson, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Thomas, Richard
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Geppert, Wolf
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Haag, Nicole
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Reinhed, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Rosén, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Larsson, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Danared, Håkan
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Rensfelt, K.-G
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Liljeby, Leif
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Bagge, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Björkhage, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Blom, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Löfgren, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Källberg, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Simonsson, Ansgar
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Paál, Andras
    Stockholms universitet, Naturvetenskapliga fakulteten, Manne Siegbahn-laboratoriet.
    Zettergren, Henning
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    Cederquist, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
    DESIREE as a new tool for interstellar ion chemistry2008Ingår i: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 7, nr 3-4, s. 205-208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel cryogenic electrostatic storage device consisting of two ion-beam storage rings with a common straight section for studies of interactions between oppositely charged ions at low and well-defined relative velocities is under construction at Stockholm University. Here we consider the prospect of using this new tool to measure cross-sections and rate coefficients for mutual neutralization reactions of importance in interstellar ion chemistry in general and specifically in cosmic pre-biotic ion chemistry.

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