| 21. |
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| 22. |
- Stolper, E.M., et al.
(författare)
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The petrochemistry of Jake_M : A martian mugearite
- 2013
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 341:6153
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Tidskriftsartikel (refereegranskat)abstract
- “Jake_M,” the first rock analyzed by the Alpha Particle X-ray Spectrometer instrument on the Curiosity rover, differs substantially in chemical composition from other known martian igneous rocks: It is alkaline (>15% normative nepheline) and relatively fractionated. Jake_M is compositionally similar to terrestrial mugearites, a rock type typically found at ocean islands and continental rifts. By analogy with these comparable terrestrial rocks, Jake_M could have been produced by extensive fractional crystallization of a primary alkaline or transitional magma at elevated pressure, with or without elevated water contents. The discovery of Jake_M suggests that alkaline magmas may be more abundant on Mars than on Earth and that Curiosity could encounter even more fractionated alkaline rocks (for example, phonolites and trachytes).
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| 23. |
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| 24. |
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| 25. |
- Weber, A, et al.
(författare)
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Mitochondria play a central role in apoptosis induced by a-tocopheryl succinate, an agent with antineoplastic activity : Comparison with receptor-mediated pro-apoptotic signaling
- 2003
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 42:14, s. 4277-4291
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Tidskriftsartikel (refereegranskat)abstract
- a-Tocopheryl succinate (a-TOS) is a semisynthetic vitamin E analogue with high pro-apoptotic and anti-neoplastic activity [Weber, T et al. (2002) Clin. Cancer Res. 8, 863-869]. Previous studies suggested that it acts through destabilization of subcellular organelles, including mitochondria, but compelling evidence is missing. Cells treated with a-TOS showed altered mitochondrial structure, generation of free radicals, activation of the sphingomyelin cycle, relocalization of cytochrome c and Smac/Diablo, and activation of multiple caspases. A pan-caspase inhibitor suppressed caspase-3 and -6 activation and phosphatidyl serine externalization, but not decrease of mitochondrial membrane potential or generation of radicals. For a-TOS, but not Fas or TRAIL, apoptosis was suppressed by caspase-9 inhibition, while TRAIL- and Fas-resistant cells overexpressing cFLIP or CrmA were susceptible to a-TOS. The central role of mitochondria was confirmed by resistance of mtDNA-deficient cells to a-TOS, by regulation of a-TOS apoptosis by Bcl-2 family members, and by anti-apoptotic activity of mitochondrially targeted radical scavengers. Co-treatment with a-TOS and anti-Fas IgM showed their cooperative effect, probably by signaling via different, convergent pathways. These data provide an insight into the molecular mechanism, by which a-TOS kills malignant cells, and advocate its testing as a potential anticancer agent or adjuvant.
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| 26. |
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| 27. |
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| 28. |
- Webster, Christopher R., et al.
(författare)
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Mars methane detection and variability at Gale crater
- 2015
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 347:6220, s. 415-417
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Tidskriftsartikel (refereegranskat)abstract
- Reports of plumes or patches of methane in the Martian atmosphere that vary over monthly timescales have defied explanation to date. From in situ measurements made over a 20-month period by the Tunable Laser Spectrometer (TLS) of the Sample Analysis at Mars (SAM) instrument suite on Curiosity at Gale Crater, we report detection of background levels of atmospheric methane of mean value 0.69 ± 0.25 ppbv at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet (UV) degradation of accreted interplanetary dust particles (IDP’s) or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period, we observed elevated levels of methane of 7.2 ± 2.1 (95% CI) ppbv implying that Mars is episodically producing methane from an additional unknown source.
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