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- Bagdadi, Omar, et al.
(författare)
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Utveckling av mätinstrument för registrering av säkerhetskritiska händelser i motorfordon
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ett mätinstrument för registrering av trafikkonflikter i fordon via ”Jerk” har tagits fram. Metoden bygger på sambandet mellan ”Jerk” (en plötslig förändring i retardationen) och trafikkonflikt. Utrustningen består av en accelerometer, en liten videokamera, GPS samt datalogg för registrering av händelser (bildsekvens och kördata som föregick en säkerhetskritisk händelse). Resultaten från testkörningarna visar att instrumentet är kapabel till att mäta och registrera accelerationsprofiler med tillräckligt hög noggrannhet för att kunna skilja inbromsningsförlopp för planerade kraftiga inbromsningar från oplanerade nödbromsningar. Detta görs genom att analysera första derivatan av accelerationsprofilen, s.k. ”Jerks”.
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| 4. |
- Berggreen, Christine, et al.
(författare)
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Protein kinase B activity is required for the effects of insulin on lipid metabolism in adipocytes.
- 2009
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Ingår i: American Journal of Physiology: Endocrinology and Metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 296, s. 635-646
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Tidskriftsartikel (refereegranskat)abstract
- Protein kinase B is known to mediate a number of biological responses to insulin and growth factors, its role in glucose uptake being one of the most extensively studied. In this paper, we have employed a recently described allosteric inhibitor of PKB, Akti, to clarify the role of PKB in lipid metabolism in adipocytes - a subject that has received less attention. Pretreatment of primary rat and 3T3L1 adipocytes with Akti resulted in dose-dependent inhibition of PKB phosphorylation and activation in response to insulin, without affecting upstream insulin signaling (IR, IRS) or the insulin-induced PI3-K dependent activation of the ERK/RSK pathway. PKB activity was required for the insulin-induced activation of PDE3B and for the anti-lipolytic action of insulin. Moreover, inhibition of PKB activity resulted in a reduction in de novo lipid synthesis and in the ability of insulin to stimulate this process. The regulation of the rate-limiting lipogenic enzyme ACC by insulin through dephosphorylation of S79, which is a target for AMPK, was dependent on the presence of active PKB. Lastly, AMPK was shown to be phosphorylated by PKB on S485 in response to insulin and this was associated with a reduction in AMPK activity. In summary, we propose that PKB is required for the positive effects of insulin on lipid storage, and that regulation of PDE3B and AMPK by PKB is important for these effects. Key words: Akt, PDE3B, ACC, AMPK, lipogenesis.
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- Dahl, Göran, 1978-, et al.
(författare)
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Hepatitis C virus NS3 protease is activated by low concentrations of protease inhibitors
- 2009
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 48:48, s. 11592-11602
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Tidskriftsartikel (refereegranskat)abstract
- The nonstructural protein 3 (NS3) of hepatitis C virus (HCV) is a bifunctional enzyme with a protease and a helicase functionality located in each of the two domains of the single peptide chain. There is little experimental evidence for a functional role of this unexpected arrangement since artificial single domain forms of both enzymes are catalytically competent. We have observed that low concentrations of certain protease inhibitors activate the protease of full-length NS3 from HCV genotype 1a with up to 100%, depending on the preincubation time and the inhibitor used. The activation was reduced, but not eliminated, by increased ionic strength, lowered glycerol concentration, or lowered pH. In all cases, it was at the expense of a significant loss of activity. Activation was not seen with the artificial protease domain of genotype 1b NS3 fused with a fragment of the NS4A cofactor. This truncated and covalently modified enzyme form was much less active and exhibited fundamentally different catalytic properties to the full-length NS3 protease without the fused cofactor. The most plausible explanation for the activation was found to involve a slow transition between two enzyme conformations, which differed in their catalytic ability and affinity for inhibitors. Equations derived based on this assumption resulted in better fits to the experimental data than the equation for simple competitive inhibition. The mechanism may involve an inhibitor-induced stabilization of the helicase domain in a conformation that enhances the protease activity, or an improved alignment of the catalytic triad in the protease. The proposed mnemonic mechanism and derived equations are viable for both these explanations and can serve as a basic framework for future studies of enzymes activated by inhibitors or other ligands.
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- Eriksson, Sandra, et al.
(författare)
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Development, evaluation and application of tripeptidyl-peptidase II sequence signatures
- 2009
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Ingår i: Archives of Biochemistry and Biophysics. - : Elsevier BV. - 0003-9861 .- 1096-0384. ; 484:1, s. 39-45
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Tidskriftsartikel (refereegranskat)abstract
- Tripeptidyl-peptidase II (TPP II) is a cytosolic peptidase that has been implicated in fat formation and cancer, apparently independent of the enzymatic activity. In search for alternative functional regions, conserved motifs were identified and eleven signatures were constructed. Seven of the signatures covered previously investigated residues, whereas the functional importance of the other motifs is unknown. This provides directions for future investigations of alternative activities of TPP II. The obtained signatures provide an efficient bioinformatic tool for the identification of TPP II homologues. Hence, a TPP II sequence homologue from fission yeast, Schizosaccharomyces pombe, was identified and demonstrated to encode the TPP II-like protein previously reported as multicorn. Furthermore, an homologous protein was found in the prokaryote Blastopirellula marina, albeit the TPP II function was apparently not conserved. This gene is probably the result of a rare gene transfer from eukaryote to prokaryote.
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- Hobein, Matthias, et al.
(författare)
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Re-trapping and cooling of highly-charged
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 163, s. 012109-
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Tidskriftsartikel (refereegranskat)abstract
- Presently, a trapping system for cooling highly-charged ions (HCI) is being set up at AlbaNova at Stockholm University. The experiment aims at production of low temperature (emittance) HCI at very low energy. HCI are extracted from the new Stockholm EBIT (S-EBIT) before evaporative cooling is applied in a Penning trap. In the future the cooled ions will be injected into the precision trap of the high-precision mass spectrometer SMILETRAP II. In first tests the emittance of trapped ions was measured and it was shown that highly and low-charged ions could be simultaneously stored
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- Olsen, Are, 1972, et al.
(författare)
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Overview of the Nordic Seas CARINA data and salinity measurements
- 2009
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Ingår i: Earth System Science Data Discussions. - 1866-3591. ; 2, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic). The data have been subject to rigorous quality control (QC) in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS), the Atlantic (ATL) and the Southern Ocean (SO). With the adjustments the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004) and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. The Arctic Mediterranean Seas includes the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. This contribution provides an overview of the CARINA data from the Nordic Seas and summarises the findings of the QC of the salinity data. One cruise had salinity data that were of questionable quality, and these have been removed from the data product. An evaluation of the consistency of the quality controlled salinity data suggests that they are consistent to at least 0.05.
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| 9. |
- Omar, Bilal, et al.
(författare)
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Regulation of AMP-activated protein kinase by cAMP in adipocytes: Roles for phosphodiesterases, protein kinase B, protein kinase A, Epac and lipolysis.
- 2009
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Ingår i: Cellular Signalling. - : Elsevier BV. - 1873-3913 .- 0898-6568. ; 21, s. 760-766
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Tidskriftsartikel (refereegranskat)abstract
- AMP-activated protein kinase (AMPK) is an important regulator of cellular energy status. In adipocytes, stimuli that increase intracellular cyclic AMP (cAMP) have also been shown to increase the activity of AMPK. The precise molecular mechanisms responsible for cAMP-induced AMPK activation are not clear. Phosphodiesterase 3B (PDE3B) is a critical regulator of cAMP signaling in adipocytes. Here we investigated the roles of PDE3B, PDE4, protein kinase B (PKB) and the exchange protein activated by cAMP 1 (Epac1), as well as lipolysis, in the regulation of AMPK in primary rat adipocytes. We demonstrate that the increase in phosphorylation of AMPK at T172 induced by the adrenergic agonist isoproterenol can be diminished by co-incubation with insulin. The diminishing effect of insulin on AMPK activation was reversed upon treatment with the PDE3B specific inhibitor OPC3911 but not with the PDE4 inhibitor Rolipram. Adenovirus-mediated overexpression of PDE3B and constitutively active PKB both resulted in greatly reduced isoproterenol-induced phosphorylation of AMPK at T172. Co-incubation of adipocytes with isoproterenol and the PKA inhibitor H89 resulted in a total ablation of lipolysis and a reduction in AMPK phosphorylation/activation. Stimulation of adipocytes with the Epac1 agonist 8-pCPT-2'O-Me-cAMP led to increased phosphorylation of AMPK at T172. The general lipase inhibitor Orlistat decreased isoproterenol-induced phosphorylation of AMPK at T172. This decrease corresponded to a reduction of lipolysis from adipocytes. Taken together, these data suggest that PDE3B and PDE4 regulate cAMP pools that affect the activation/phosphorylation state of AMPK and that the effects of cyclic AMP on AMPK involve Epac1, PKA and lipolysis.
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| 10. |
- Omar, Faisal, et al.
(författare)
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Attitudes towards priority-setting and rationing in healthcare - an exploratory survey of Swedish medical students
- 2009
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Ingår i: Scandinavian Journal of Public Health. - : Sage Publications. - 1403-4948 .- 1651-1905. ; 37:2, s. 122-130
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Tidskriftsartikel (refereegranskat)abstract
- Background: Healthcare priority-setting is inextricably linked to the challenge of providing publicly funded healthcare within a limited budget, which may result in difficult and potentially controversial rationing decisions. Despite priority-settings increasing prominence in policy and academic discussion, it is still unclear what the level of understanding and acceptance of priority-setting is at different levels of health care. Aims: The aim of this study is threefold. First we wish to explore the level of familiarity with different aspects of priority-setting among graduating medical students. Secondly, to gauge their acceptance of both established and proposed Swedish priority-setting principles. Finally to elucidate their attitudes towards healthcare rationing and the role of different actors in decision making, with a particular interest in comparing the attitudes of medical students with data from the literature examining the attitudes among primary care patients in Sweden. Methods: A cross-sectional survey containing 14 multiple choice items about priority-setting in healthcare was distributed to the graduating medical class at Linkoping University. The response rate was 92% (43/47). Results: Less than half of respondents have encountered the notion of open priority-setting, and the majority believed it to be somewhat or very unclear. There is a high degree of awareness and agreement with the established ethical principles for priority-setting in Swedish health care; however respondents are inconsistent in their application of the cost-effectiveness principle. A larger proportion of respondents were more favourable to physicians and other health personnel being responsible for rationing decisions as opposed to politicians. Conclusions: Future discussion about priority-setting in medical education should be contextualized within an explicit and open process. There is a need to adequately clarify the role of the cost-effectiveness principle in priority-setting. Medical students seem to acknowledge the need for rationing in healthcare to a greater extent when compared with previous results from Swedish primary care patients.
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