| 1. |
- Fynbo, H. O. U., et al.
(författare)
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The β-decay approach for studying 12C
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 111:1
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Tidskriftsartikel (refereegranskat)abstract
- The β-decays of the mirror nuclei 12B and 12N both populate states in 12C and they are therefore a precious source of information about this nucleus. Due to the selection rules of β-decay only 0+, 1+ and 2+ states are populated. This allows a very clean study of unbound states just above the 3α-threshold with those spin and parities. This probe has been applied in two experiments using two complementary experimental techniques: in the first the three α-particles emitted after β-decay are measured in coincidence in separate detectors using the ISOL method, while in the second method 12B and 12N are implanted in a detector and the summed energy of the three α-particles is measured directly. Preliminary results from the two approaches are presented. © 2008 IOP Publishing Ltd.
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| 2. |
- Knudsen, H. H., et al.
(författare)
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Beta-decay of 13O
- 2005
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 72:4, s. 044312-
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Tidskriftsartikel (refereegranskat)abstract
- The beta decay of O-13 has been studied at the IGISOL facility of the Jyvaskyla accelerator centre (Finland). By developing a low-energy isotope-separated beam of O-13 and using a modern segmented charged-particle detector array an improved measurement of the delayed proton spectrum was possible. Protons with energy up to more than 12 MeV are measured and the corresponding log(ft) values extracted. A revised decay scheme is constructed. The connection to molecular states and the shell model is discussed.
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| 3. |
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| 4. |
- Andersen, Felicie F., et al.
(författare)
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Assembly and structural analysis of a covalently closed nano-scale DNA cage
- 2008
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 36:4, s. 1113-1119
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Tidskriftsartikel (refereegranskat)abstract
- The inherent properties of DNA as a stable polymer with unique affinity for partner mols. detd. by the specific Watson-Crick base pairing makes it an ideal component in self-assembling structures. This has been exploited for decades in the design of a variety of artificial substrates for investigations of DNA-interacting enzymes. More recently, strategies for synthesis of more complex two-dimensional (2D) and 3D DNA structures have emerged. However, the building of such structures is still in progress and more experiences from different research groups and different fields of expertise are necessary before complex DNA structures can be routinely designed for the use in basal science and/or biotechnol. Here we present the design, construction and structural anal. of a covalently closed and stable 3D DNA structure with the connectivity of an octahedron, as defined by the double-stranded DNA helixes that assembles from eight oligonucleotides with a yield of .apprx.30%. As demonstrated by Small Angle X-ray Scattering and cryo-Transmission Electron Microscopy analyses the eight-stranded DNA structure has a central cavity larger than the apertures in the surrounding DNA lattice and can be described as a nano-scale DNA cage, Hence, in theory it could hold proteins or other bio-mols. to enable their investigation in certain harmful environments or even allow their organization into higher order structures.
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| 5. |
- Mylin, Anne K., et al.
(författare)
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Serum YKL-40 concentrations in newly diagnosed multiple myeloma patients and YKL-40 expression in malignant plasma cells
- 2006
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Ingår i: European Journal of Haematology. - 1600-0609. ; 77:5, s. 416-424
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: A potential role in cancer biology is suggested for YKL-40 (CHI3L1, HC gp-39). The purpose of this study was to evaluate the clinical value of serum YKL-40 (sYKL-40) in multiple myeloma (MM) and to examine YKL-40 expression in malignant plasma cells (MM PCs). Methods: sYKL-40 was measured by enzyme-linked immunosorbent assay (ELISA) in 82 patients with newly diagnosed MM. YKL-40 expression in immunophenotypically defined plasma cells was investigated by double-labelled immunohistochemistry in 21 MM patients and by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in cDNA archives generated by global RT-PCR in seven controls, 14 patients with monoclonal gammopathy of undetermined significance (MGUS), 45 MM patients, nine patients with extramedullary myeloma (exMM), and seven human myeloma cell lines (HMCLs). Results: sYKL-40 was elevated above a constructed reference range for healthy controls in 29% of the patients investigated. Patients with elevated sYKL-40 had reduced overall survival and event-free survival when compared to patients with normal sYKL-40, but sYKL-40 level was defeated by beta(2)-microglobulin in the multivariate analyses. Intramedullary MM PCs lacked significant expression of YKL-40, but high levels of YKL-40 expression were seen in extramedullary MM PCs from one exMM patient and in six HMCLs. Further investigations of other bone marrow (BM) cells showed YKL-40 expression in megakaryocytes, neutrophils and adherent cells from long-term BM cultures. Conclusions: In newly diagnosed MM-patients, a sYKL-40 elevated above the reference range predicts a poor clinical outcome, and YKL-40 is expressed by other BM cells than MM PCs. At this point, routine measurements of sYKL-40 are not warranted, but YKL-40 should be considered as a potential player in the pathophysiology of MM.
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| 6. |
- Norppa, H., et al.
(författare)
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Chromosomal aberrations and SCEs as biomarkers of cancer risk
- 2006
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Ingår i: Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis. - : Elsevier BV. - 1879-2871 .- 0027-5107. ; 600:1-2, s. 37-45
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have suggested that the frequency of chromosomal aberrations (CAs), but not of sister chromatid exchanges (SCEs), predicts cancer risk. We have further examined this relationship in European cohorts comprising altogether almost 22,000 subjects, in the framework of a European collaborative project (CancerRiskBiomarkers). The present paper gives an overview of some of the results of the project, especially as regards CAs and SCEs. The results confirm that a high level of CAs is associated with an increased risk of cancer and indicate that this association does not depend on the time between CA analysis and cancer detection, i.e., is obviously not explained by undetected cancer. The present evidence indicates that both chromatid-type and chromosome-type CAs predict cancer, even though some data suggest that chromosome-type CAs may have a more pronounced predictive value than chromatid-type CAs. CA frequency appears to predict cancers at various sites, although there seems to be a particular association with gastrointestinal cancers. SCE frequency does not appear to have cancer predictive value, at least partly due to uncontrollable technical variation. A number of genetic polymorphisms of xenobiotic metabolism, DNA repair, and folate metabolism affect the level of CAs and might collectively contribute to the cancer predictivity of CAs. Other factors that may influence the association between CAs and cancer include, e.g., exposure to genotoxic carcinogens and internal generation of genotoxic species. Although the association between CA level and cancer is seen at the group level, an association probably also exists for the individual, although it is not known if an individual approach could be feasible. However, group level evidence should be enough to support the use of CA analysis as a tool in screening programs and prevention policies in occupational and environmental health.
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| 7. |
- Trajkovska, V., et al.
(författare)
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BDNF downregulates 5-HT2A receptor protein levels in hippocampal cultures
- 2009
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Ingår i: Neurochemistry International. - : Elsevier BV. - 0197-0186. ; 55:7, s. 697-702
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Tidskriftsartikel (refereegranskat)abstract
- Both brain-derived neurotrophic factor (BDNF) and the serotonin receptor 2A (5-HT2A) have been related to depression pathology. Specific 5-HT2A receptor changes seen in BDNF conditional mutant mice suggest that BDNF regulates the 5-HT2A receptor level. Here we show a direct effect of BDNF on 5-HT2A receptor protein levels in primary hippocampal neuronal and mature hippocampal organotypic cultures exposed to different BDNF concentrations for either 1, 3, 5 or 7 days. In vivo effects of BDNF on hippocampal 5-HT2A receptor levels were further corroborated in (BDNF +/-) mice with reduced BDNF levels. In primary neuronal cultures, 7 days exposure to 25 and 50 ng/mL BDNF resulted in downregulation of 5-HT2A, but not of 5-HT1A, receptor protein levels. The BDNF-associated downregulation of 5-HT2A receptor levels was also observed in mature hippocampal organotypic cultures, excluding confounding effects of BDNF on immature tissue. BDNF +/- mice showed significant increased 5-HT2A receptor levels in hippocampus confirming the association between 5-HT2A receptor and BDNF levels in vivo. In conclusion, our results point to a regulatory role of BDNF on 5-HT2A receptor levels. This interaction may be an important mechanism in the role of BDNF in affective disorders emphasizing the need for further elucidating the specificity and the mechanism behind this regulation. (C) 2009 Elsevier Ltd. All rights reserved.
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| 8. |
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| 9. |
- Dunkel, Mathias, et al.
(författare)
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SuperScent--a database of flavors and scents
- 2009
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 37, s. 291-294
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Tidskriftsartikel (refereegranskat)abstract
- Volatiles are efficient mediators of chemical communication acting universally as attractant, repellent or warning signal in all kingdoms of life. Beside this broad impact volatiles have in nature, scents are also widely used in pharmaceutical, food and cosmetic industries, so the identification of new scents is of great industrial interest. Despite this importance as well as the vast number and diversity of volatile compounds, there is currently no comprehensive public database providing information on structure and chemical classification of volatiles. Therefore, the database SuperScent was established to supply users with detailed information on the variety of odor components. The version of the database presented here comprises the 2D/3D structures of approximately 2100 volatiles and around 9200 synonyms as well as physicochemical properties, commercial availability and references. The volatiles are classified according to their origin, functionality and odorant groups. The information was extracted from the literature and web resources. SuperScent offers several search options, e.g. name, Pubchem ID number, species, functional groups, or molecular weight. SuperScent is available online at: http://bioinformatics.charite.de/superscent.
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| 10. |
- Finnegan, S. M., et al.
(författare)
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The dispersive Alfven wave in the time-stationary limit with a focus on collisional and warm-plasma effects
- 2008
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 15:5, s. 052108-
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Tidskriftsartikel (refereegranskat)abstract
- A nonlinear, collisional, two-fluid model of uniform plasma convection across a field-aligned current (FAC) sheet, describing the stationary Alfven (StA) wave, is presented. In a previous work, Knudsen showed that, for cold, collisionless plasma [D. J. Knudsen, J. Geophys. Res. 101, 10761 (1996)], the stationary inertial Alfven (StIA) wave can accelerate electrons parallel to a background magnetic field and cause large, time-independent plasma-density variations having spatial periodicity in the direction of the convective flow over a broad range of spatial scales and energies. Knudsen suggested that these fundamental properties of the StIA wave may play a role in the formation of discrete auroral arcs. Here, Knudsen's model has been generalized for warm, collisional plasma. From this generalization, it is shown that nonzero ion-neutral and electron-ion collisional resistivity significantly alters the perpendicular ac and dc structure of magnetic-field-aligned electron drift, and can either dissipate or enhance the field-aligned electron energy depending on the initial value of field-aligned electron drift velocity. It is also shown that nonzero values of plasma pressure increase the dominant Fourier component of perpendicular wavenumber.
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| 11. |
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| 12. |
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| 13. |
- Larsen, Nicolaj Krog, et al.
(författare)
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Late Quaternary ice sheet, lake and sea history of southwest Scandinavia - a synthesis
- 2009
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Ingår i: Boreas. - : Wiley. - 1502-3885 .- 0300-9483. ; 38:4, s. 732-761
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Forskningsöversikt (refereegranskat)abstract
- Based on a large number of new boreholes in northern Denmark, and on the existing data, a revised event-stratigraphy is presented for southwestern Scandinavia. Five significant Late Saalian to Late Weichselian glacial events, each separated by periods of interglacial or interstadial marine or glaciolacustrine conditions, are identified in northern Denmark. The first glacial event is attributed to the Late Saalian c. 160-140 kyr BP, when the Warthe Ice Sheet advanced from easterly and southeasterly directions through the Baltic depression into Germany and Denmark. This Baltic ice extended as far as northern Denmark, where it probably merged with the Norwegian Channel Ice Stream (NCIS) and contributed to a large discharge of icebergs into the Norwegian Sea. Following the break up, marine conditions were established that persisted from the Late Saalian until the end of the Early Weichselian. The next glaciation occurred c. 65-60 kyr BP, when the Sunds circle divide re ice advanced from the north into Denmark and the North Sea, where the Scandinavian and British Ice Sheets merged. During the subsequent deglaciation, large ice-dammed lakes formed before the ice disintegrated in the Norwegian Channel, and marine conditions were re-established. The following Ristinge advance from the Baltic, initiated c. 55 kyr BP, also reached northern Denmark, where it probably merged with the NCIS. The deglaciation, c. 50 kyr BP, was followed by a long period of marine arctic conditions. Around 30 kyr BP, the Scandinavian Ice Sheet expanded from the north into the Norwegian Channel, where it dammed the Kattegat ice lake. Shortly after, c. 29 kyr BP, the Kattegat advance began, and once again the Scandinavian and British Ice Sheets merged in the North Sea. The subsequent retreat to the Norwegian Channel led to the formation of Ribjerg ice lake, which persisted from 27 to 23 kyr BP. The expansion of the last ice sheet started c. 23 kyr BP, when the main advance occurred from north-northeasterly directions into Denmark. An ice-dammed lake was formed during deglaciation, while the NCIS was still active. During a re-advance and subsequent retreat c. 19 kyr BP, a number of tunnel-valley systems were formed in association with ice-marginal positions. The NCIS finally began to break up in the Norwegian Sea 18.8 kyr BP, and the Younger Yoldia Sea inundated northern Denmark around 18 kyr BP. The extensive amount of new and existing data applied to this synthesis has provided a better understanding of the timing and dynamics of the Scandinavian Ice Sheet (SIS) during the last c. 160 kyr. Furthermore, our model contributes to the understanding of the timing of the occasional release of large quantities of meltwater from the southwestern part of the SIS that are likely to enter the North Atlantic and possibly affect the thermohaline circulation.
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| 14. |
- Pasquet, Remy S., et al.
(författare)
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Long-distance pollen flow assessment through evaluation of pollinator foraging range suggests transgene escape distances
- 2008
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 105:36, s. 13456-13461
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Tidskriftsartikel (refereegranskat)abstract
- Foraging range, an important component of bee ecology, is of considerable interest for insect-pollinated plants because it determines the potential for outcrossing among individuals. However, long-distance pollen flow is difficuit to assess, especially when the plant also relies on self-pollination. Pollen movement can be estimated indirectly through population genetic data, but complementary data on pollinator flight distances is necessary to validate such estimates. By using radio-tracking of cowpea pollinator return flights, we found that carpenter bees visiting cowpea flowers can forage up to 6 km from their nest. Foraging distances were found to be shorter than the maximum flight range, especially under adverse weather conditions or poor reward levels. From complete flight records in which bees visited wild and domesticated populations, we conclude that bees can mediate gene flow and, in some instances, allow transgene (genetically engineered material) escape over several kilometers. However, most between-flower flights occur within plant patches, while very few occur between plant patches.
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| 15. |
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