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| 2. |
- Fälthammar, Carl-Gunne, et al.
(författare)
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Significance of magnetospheric research for progress in astrophysics
- 1978
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 275, s. 185-188
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Tidskriftsartikel (refereegranskat)abstract
- Recent in situ measurements have led to a substantial revision of our picture of the magnetosphere and parts of the heliosphere. This concerns the character and distribution of electric fields and currents, the ways in which charged particles are energised, and the chemical composition of the magnetospheric plasma. This revision reflects the fact that real cosmic plasmas behave in fundamentally different ways than predicted by the traditional, idealised models used in magnetospheric physics and in astrophysics. The new understanding of the general properties of cosmic plasma gives us an improved basis on which to interpret astrophysical observations.
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| 3. |
- Holm, Elis, et al.
(författare)
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Global fallout of curium
- 1978
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 273:5660, s. 289-290
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Tidskriftsartikel (refereegranskat)abstract
- THE search for 242mAm (t1/2=152 yr) in environmental samples has involved detection of its daughter 242Cm (t 1/2=163 d) (refs 1-3). These samples were contaminated by transuranium nuclides either from a nuclear fuel reprocessing plant or from a thermonuclear test fallout. A logical consequence was then to analyse global fallout-contaminated samples for 242Cm and 244Cm to establish the present distribution and global contamination of our environment by these transuranium elements. We have chosen the lichen Cladonia alpestris, which is an excellent bioindicator for atmospheric fallout and we present the results here. The samples have been stored in the laboratory for 5-16 yr. Thus, 242mAm and 242Cm were in sequelar radioactive equilibrium. The 242Cm present in the aged samples therefore represents the 242mAm present in the fallout. The results indicate a 242mAm/239+240Pu activity ratio of about 0.003% in global fallout.
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| 5. |
- Larsson, P O, et al.
(författare)
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New Approach to Steroid Conversion Using Immobilised Microorganisms
- 1976
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 263:5580, s. 796-797
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Tidskriftsartikel (refereegranskat)abstract
- The marked increase in demand for contraceptives and anti-inflammatory agents such as cortisol and prednisolone, combined with a diminishing supply of steroid raw materials may lead to shortages of steroid drugs1. Thus it is important to develop new sources for steroids as well as to devise more efficient means for steroid conversions. Here we report a new approach to steroid transformation in which activated immobilised microorganisms are utilised and which represents a promising alternative to conventional microbial transformation processes.
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| 7. |
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| 8. |
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| 9. |
- Perricaudet, Michel, et al.
(författare)
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Structure of two spliced mRNAs from the transforming region of human subgroup C adenoviruses
- 1979
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 281:5733, s. 694-696
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The papova viruses and the human adenoviruses are widely used as a model system to study cell transformation in vitro. In subgroup C human adenoviruses, fragment HpaI-E, which comprises as little as 4.5% of the adenovirus type 5 (ad5) DNA, is sufficient for transformation of rat embryo cells1. Analysis of messenger RNAs (mRNAs) from the transforming region of adenoviruses type 2 (ad2) has identified several spliced mRN A species2−4. Promoter mapping studies indicate that the leftmost early region contains two separate transcription units, E1A and E1B (ref. 5) (Fig. 1a). Region E1A is approximately equivalent HpaI-E. The complete nucleotide sequence of the HpaI-E fragment of ad5 was recently reported6. However, the spliced nature of early adenovirus mRNAs prevents a prediction of the amino acid sequence of the corresponding polypeptides directly from the DNA sequence. To study the structure of early ad2 mRNAs at the nucleotide level, we have used molecular cloning procedures to amplify the appropriate mRNA sequences. In this report, clones corresponding to the 12S and 13S mRNA from region E1A (Fig. 1c) have been isolated and characterised by hybridisation and sequence analysis. Our results enable us to predict the primary sequence of two related polypeptides from region E1A of human subgroup C adenoviruses.
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| 10. |
- Ross, Russell George, et al.
(författare)
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Thermal conductivity of allotropic modifications of ice
- 1976
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 259, s. 553-554
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Tidskriftsartikel (refereegranskat)abstract
- The pressure-temperature phase diagram of H2O comprises several solid phases, differening in their crystal structure. Ice offers an unusual oppurtunity for investigating how the different modes of stacking and the slight distortions of otherwise identical molecules influence the conduction of heat. There are no previous studies of the thermal conductivity of ice, except for the phase Ih at atmospheric pressure. We report here the first measurements of the thermal conductivity of the high pressure forms II, III, V and VI. Each of these modifications has a higher density, and a lower thermal conductivity, than ordinary ice, Ih. Ice Ih seems to be the first example of an insulator which has a decreasing thermal conductivity under increasing pressure. Our findings show that all these forms of ice have a positive thermal expansion coefficient.
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