| 1. |
- Leijon, M., et al.
(författare)
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STRUCTURAL CHARACTERIZATION OF PNA-DNA DUPLEXES BY NMR - EVIDENCE FOR DNA IN A B-LIKE CONFORMATION
- 1994
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 1520-4995 .- 0006-2960. ; 33:33, s. 9820-9825
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Tidskriftsartikel (refereegranskat)abstract
- The nucleic acid analogues PNA (peptide nucleic acids) hybridize with DNA of complementary sequence. The solution structures of two PNA-DNA duplexes, H-(GCTATGTC)-NH2.d(GACATAGC) and H-(GTAGATCACT)-NH2.d(AGTGATCTAC), have been studied by H-1 NMR. It was found that the PNA-DNA hybrids are base paired by hydrogen bonds, most likely of the Watson-Crick type. From two-dimensional NOESY and COSY results it is concluded that the DNA strand in the PNA-DNA complex adopts a B-like structure with the deoxyribose sugars in the C2'-endo conformation.
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| 2. |
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| 3. |
- Eriksson, A M, et al.
(författare)
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Studies on the intracellular distributions of soluble epoxide hydrolase and of catalase by digitonin-permeabilization of hepatocytes isolated from control and clofibrate-treated mice.
- 1991
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Ingår i: European Journal of Biochemistry. - 0014-2956 .- 1432-1033. ; 198:2
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Tidskriftsartikel (refereegranskat)abstract
- Digitonin permeabilization of hepatocytes from control and clofibrate-treated (0.5% by mass, 10 days) male C57bl/6 mice was used to study the intracellular distributions of soluble ('cytosolic') epoxide hydrolase and of catalase. The following conclusions were drawn. (1) About 60% of the total soluble epoxide hydrolase activity in control mouse hepatocytes is situated in the cytosol. (2) The rest is not mitochondrial, but probably peroxisomal. (3) Of the total catalase activity in control mouse hepatocytes, 5-10% is found in the cytosol. (4) Treatment of mice with clofibrate increases the total hepatocyte activity of soluble epoxide hydrolase 4-fold, but does not influence the relative distribution of this enzyme between cytosol and peroxisomes. (5) The total catalase activity is increased 3.5-fold by clofibrate treatment and 15-35% of this activity is shifted from the peroxisomes to the cytosol.
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| 4. |
- Eriksson, M., et al.
(författare)
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BINDING OF DELTA- RU(PHEN)(3) (2+) AND LAMBDA- RU(PHEN)(3) (2+) TO D(CGCGATCGCG) (2) STUDIED BY NMR
- 1994
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 1520-4995 .- 0006-2960. ; 33:17, s. 5031-5040
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Tidskriftsartikel (refereegranskat)abstract
- The interactions of the Delta and Delta enantiomers of the chiral metal complex [Ru(phen)(3)](2+) (phen = 1,10-phenanthroline) with the oligonucleotide duplex [d(CGCGATCGCG)](2) have been studied with NMR and CD spectroscopy. From NOESY data it is shown that the interaction primarily takes place in the minor groove of the oligonucleotide which remains in a B-like conformation. The observed NOEs also provide evidence that the metal complexes preferentially bind to the central AT region. The observed AT specificity is more pronounced with the Delta as compared to the Delta enantiomer, which interacts with a larger part of the oligonucleotide. Furthermore, the NOESY data show that neither of the enantiomers binds by classical intercalation. This is also supported by a comparison study of the analogue [Ru(phen)(2)DPPZ](2+) (DPPZ = dipyrido[ 3,2-a:2',3'-c] phenazine) which intercalates in DNA. The NMR as well as the CD results show that the Delta and Delta enantiomers of [Ru(phen)(3)](2+) bind in different modes to [d(CGCGATCGCG)](2). Comparison of CD spectra of the metal complex in the presence of [d(CGCGATCGCG)](2), poly(dAdT).poly(dAdT), poly(dGdC).poly(dGdC), and calf thymus DNA suggests that these binding modes are independent of DNA sequence. The results are found to be compatible with binding of Delta-[Ru(phen)(3)](2+) by insertion of two phenanthroline ligands into the minor groove, causing minor distortions of the DNA structure, whereas the Delta enantiomer binds in a mode that leaves the DNA structure unaffected.
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| 5. |
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| 6. |
- Erlandson, R. E., et al.
(författare)
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Freja observations of electromagnetic ion cyclotron ELF waves and transverse oxygen ion acceleration on auroral field lines
- 1994
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Ingår i: Geophysical Research Letters. - 0094-8276. ; 21:17, s. 1855-1858
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Tidskriftsartikel (refereegranskat)abstract
- Extremely low-frequency (ELF) magnetic and electric field plasma wave emissions were recorded on 2 October 1993 on auroral field lines by the Magnetic Field Experiment during Freja orbit 4770. The ELF wave frequencies were below the local oxygen gyrofrequency (25 Hz) and between the helium and proton gyrofrequencies (100 to 400 Hz). The ELF waves, interpreted as electromagnetic ion cyclotron (EMIC) waves, were observed in a region of inverted-v-type electron precipitation. The EMIC waves were correlated over time with auroral and lower energy (≈ 100 eV) electrons, which are both possible sources of free energy, and also with transversely accelerated oxygen ions. The waves above the helium gyrofrequency were more closely correlated with the transverse oxygen ion acceleration than the waves below the oxygen gyrofrequency. These observations are consistent with a scenario in which electron beams generate EMIC waves, which then produce transverse oxygen ion acceleration through a gyroresonant interaction.
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| 7. |
- Hallberg, Lillemor R-M, 1942, et al.
(författare)
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Psychometric evaluation of a Swedish version of the communication strategies scale of the communication profile for the hearing impaired.
- 1992
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Ingår i: Journal of speech and hearing research. - 0022-4685. ; 35:3, s. 666-74
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Tidskriftsartikel (refereegranskat)abstract
- The Communication Strategies scale of the Communication Profile for the Hearing Impaired (CPHI) was translated into Swedish and used in several studies of people with hearing impairment (Hallberg & Carlsson, in press; Hallberg, Erlandsson, & Carlsson, 1991). In this study the scale was evaluated in terms of descriptive statistics, corrected item-total correlations, principal component analysis, and internal consistency reliability. Agreement with results from American studies is surprisingly good. Normative data based on three samples are presented: a general Swedish hearing-impaired sample with predominantly sensorineural hearing loss (N = 199), a subgroup of 105 younger subjects with noise-induced hearing loss, and a subgroup of 39 older subjects with sensorineural hearing loss due to heredity and/or old age. A significantly more frequent use of maladaptive behaviors (p less than .001) and verbal communication strategies (p less than .01) was reported by older subjects with age-related and/or hereditary hearing loss than by younger subjects with noise-induced hearing loss. The Communication Strategies scale seems to be an adequately reliable and clinically useful instrument for assessing adaptive and maladaptive strategies in hearing-impaired subjects.
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| 8. |
- Knudsen, D. J., et al.
(författare)
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Sub-kilometer thermal plasma structure near 1750 km altitude in the polar cusp/cleft
- 1994
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Ingår i: Geophysical Research Letters. - 0094-8276. ; 21:17, s. 1907-1910
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Tidskriftsartikel (refereegranskat)abstract
- We present Freja Cold Plasma Analyzer (CPA) measurements from an encounter with the low altitude (approx.1750 km) polar cusp during which the CPA measured 2-D images of the thermal (0-16 eV) particle distributions at 1.2 s time resolution, and simultaneously made rapid estimates (600/s) of integrated thermal particle flux into the instrument. The high resolution data show bursty ion flux enhancements of the order of tens of percent on time scales of tens of ms, or alternatively, hundreds of m spatial scales. The flux of electrons from 0-16 eV also varied by tens of percent and on temporal/spatial scales comparable to those in the ion cases. There is some evidence that the thermal particle flux variations are associated with intense low-frequency electromagnetic fluctuations with temporal/spatial scales identical to those seen by the CPA (tens of ms. hundreds of m).
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| 9. |
- Persson, M. A. L., et al.
(författare)
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Near-Earth substorm onset - a coordinated study
- 1994
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 21:17, s. 1875-1878
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Tidskriftsartikel (refereegranskat)abstract
- We present simultaneous satellite and ground-based measurements of a substorm. Throughout the initial substorm expansion, southward drifting arcs are observed poleward of the expanding substorm aurora, indicating two independent systems of particle precipitation. Freja passes the brightening onset arc in the topside ionosphere near the moment of the substorm onset, observing an Alfven wave, field aligned current and oxygen ion outflow. The substorm onset occurs at low magnetospheric L-shells, near the poleward edge of the region of trapped particles. The location and time for the substorm injection are confirmed by geostationary spacecraft together with magnetometers, all-sky cameras and radar on the ground. We believe that the substorm onset may be triggered by modification of the oxygen content of the inner magnetosphere during the growth-phase caused by ionospheric ion outflow.
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| 10. |
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