| 11. |
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| 12. |
- Liddell, P. A., et al.
(författare)
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Photonic switching of photoinduced electron transfer in a dihydropyrene-porphyrin-fullerene molecular triad
- 2004
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Ingår i: Journal of the American Chemical Society. ; 126:15, s. 4803-4811
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Tidskriftsartikel (refereegranskat)abstract
- Photonic control of photoinduced electron transfer has been demonstrated in a dimethyldihydropyrene (DHP) porphyrin (P) fullerene (C-60) molecular triad. In the DHP-P-C-60 form of the triad, excitation of the porphyrin moiety is followed by photoinduced electron transfer to give a DHP-P.+-C-60(.-) charge-separated state, which evolves by a charge shift reaction to DHP.+-P-C-60(.-). This final state has a lifetime of 2 mus and is formed in an overall yield of 94%. Visible (greater than or equal to300 nm) irradiation of the triad leads to photoisomerization of the DHP moiety to the cyclophanediene (CPD). Excitation of the porphyrin moiety of CPD-P-C-60 produces a short-lived (
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| 13. |
- Pohjola, V, et al.
(författare)
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Effect of periodic melting on geochemical and isotopic signals in an ice core from Lomonosovfonna, Svalbard
- 2002
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Ingår i: J.Geophys.Res.. ; 107:D4, s. ACL 1-14
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Tidskriftsartikel (refereegranskat)abstract
- In this work we examine the quality of the atmospherically deposited signals in an ice core taken from a periodically melting ice field, Lomonosovfonna on central Spitsbergen, Svalbard. The aim is to investigate how much the atmospheric deposited signals in the stratigraphy of ice pack are changed by periodic melting of the ice. To determine the impact of this melting on the stratigraphy found in the ice core, we use three diagnostics: 1) Association between peak values in the ice chemical and isotopic record and ice facies type; 2) Number of “annual” cycles in these records compared with independently-determined number of years represented in the ice core; 3) Statistical comparison between the isotopic record in the ice core and the isotope records from coastal stations from the same region. We find that during warm summers as much as 50% of the annual accumulation may melt and percolate into the firn, and in a median year this decreases to ca. 25 %. As a consequence of percolation the most mobile acids show upto 50 % higher concentrations in bubble poor ice facies compared with facies that are less affected by melt. Most of the other chemical species are less affected than the strong acids, and the stable water isotopes show little evidence of mobility Annual, or bi-annual cycles are detected in most parameters, and the water isotope record has a comparable statistical distribution to isotopic records from coastal stations. We conclude that ice cores from sites like Lomonosovfonna preserve an useful environmental record despite melt events and percolation, where most parameters displays an annual, or in poor cases a bi-annual atmospheric signal.
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| 14. |
- Pohjola, V, et al.
(författare)
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Reconstruction of three centuries of annual accumulation rates based on the record of stable isotopes of water from Lomonosovfonna, Svalbard
- 2002
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Ingår i: Annals of glaciology. ; 35, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- We use the upper 81 m of the record of stable isotopes of water from a 122 m long ice core from Lomonosovfonna, central Spitsbergen, to construct an ice core chronology and the annual accumulation rates over the ice field. The isotope cycles are counted in the ice core record using a model that neglects short wavelength and low amplitude cycles. We find approximately the same number of ä18O cycles as years between known reference horizons, and assume these cycles represent annual cycles. Testing the validity of this assumption using cycles in äD shows that both records give similar numbers of cycles. Using the ä18O chronology, and de-compressing the accumulation records using the Nye flow model, we calculate the annual accumulation for the ice core site back to 1715 AD. We find that the average accumulation rate from 1715 to 1950 o was on average 0.30 m w.e. Accumulation rates increased ca. 25% during the later part of the 20th century to an average of 0.41 m w.e. for the period 1950 – 1997. The accumulation rates show highly significant 2.1 and 21 year periodicities, which gives credibility to our time scale.
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| 15. |
- Ricci, R., et al.
(författare)
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Requirement of JNK2 for scavenger receptor A-mediated foam cell formation in atherogenesis
- 2004
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Ingår i: Science. - 1095-9203. ; 306:5701, s. 1558-61
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Tidskriftsartikel (refereegranskat)abstract
- In vitro studies suggest a role for c-Jun N-terminal kinases (JNKs) in proatherogenic cellular processes. We show that atherosclerosis-prone ApoE-/- mice simultaneously lacking JNK2 (ApoE-/- JNK2-/- mice), but not ApoE-/- JNK1-/- mice, developed less atherosclerosis than do ApoE-/- mice. Pharmacological inhibition of JNK activity efficiently reduced plaque formation. Macrophages lacking JNK2 displayed suppressed foam cell formation caused by defective uptake and degradation of modified lipoproteins and showed increased amounts of the modified lipoprotein-binding and -internalizing scavenger receptor A (SR-A), whose phosphorylation was markedly decreased. Macrophage-restricted deletion of JNK2 was sufficient to decrease atherogenesis. Thus, JNK2-dependent phosphorylation of SR-A promotes uptake of lipids in macrophages, thereby regulating foam cell formation, a critical step in atherogenesis.
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| 16. |
- Scherer, SW, et al.
(författare)
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Human chromosome 7: DNA sequence and biology
- 2003
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 300:5620, s. 767-772
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Tidskriftsartikel (refereegranskat)abstract
- DNA sequence and annotation of the entire human chromosome 7, encompassing nearly 158 million nucleotides of DNA and 1917 gene structures, are presented. To generate a higher order description, additional structural features such as imprinted genes, fragile sites, and segmental duplications were integrated at the level of the DNA sequence with medical genetic data, including 440 chromosome rearrangement breakpoints associated with disease. This approach enabled the discovery of candidate genes for developmental diseases including autism.
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