| 1. |
- Sundberg, C, et al.
(författare)
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Comparison of the potencies of (+)- and (-)-2-ethylhexanoic acid in causing peroxisome proliferation and related biological effects in mouse liver.
- 1994
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Ingår i: Chirality. - : Wiley. - 0899-0042 .- 1520-636X. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Male C57BL/6 mice were exposed to 1% (w/w) (+)- or (-)-2-ethylhexanoic acid or an equimolar mixture of these enantiomers in their diet for 4 or 10 days. A significant increase in liver weight and a 2- to 3-fold increase in the protein content of the mitochondrial fraction were seen in all cases. Peroxisomal palmitoyl-CoA oxidation was increased 2- to 3.5-fold after 4 days of treatment and 4- to 5-fold after 10 days, while the corresponding increases in peroxisomal lauroyl-CoA oxidase activity were 2- to 3-fold and 9- to 12-fold, respectively. Peroxisomal catalase activity was unchanged, whereas the microsomal and cytosolic activities were increased 2- to 3-fold and 6- to 16-fold, respectively. These treatments also induced microsomal omega-hydroxylation of lauric acid 7-fold and soluble epoxide hydrolase activity in the mitochondrial and cytosolic fractions, as well as microsomal epoxide hydrolase activity about 50-100%. The only significant differences observed between the effects of (+)-2-ethylhexanoic acid and its (-)-enantiomer were on peroxisomal palmitoyl-CoA oxidation and lauroyl-CoA oxidase activity after 4 days of treatment. In both these cases the (+)-enantiomer resulted in increases which were 50-75% greater than those seen with the (-)-form.
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| 2. |
- Berg, C., et al.
(författare)
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Observation of a low-binding-energy peak in the 2p core-level photoemission from oxidized Al(111)
- 1993
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 47:19, s. 13063-13066
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution photoemission studies of oxidation of the Al(111) surface have been performed. The appearance of a component at lower binding energy than the metallic bulk Al emission in the Al 2p spectrum at oxygen exposures above ∼50 langmuir (1 L = 10-6 Torr s) is argued to be due to Al atoms which do not bond directly to oxygen atoms at the oxide-metal interface. Low-energy electron diffraction initially shows a 1×1 structure, which subsequently fades away at higher oxygen exposures, 400 L.
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| 3. |
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| 4. |
- NISKANEN, K, et al.
(författare)
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ANGULAR DEPENDENT MAGNETIC-PROPERTIES OF SINGLE-CRYSTAL BI-SR-CA-CU-O
- 1991
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 185, s. 2207-2208
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Tidskriftsartikel (refereegranskat)abstract
- The field, time and temperature dependence of the longitudinal component of the magnetization of a single crystal of BiSrCaCuO has been investigated by SQUID-magnetometry as a function of the tilt angle between the crystallographic c-axis and the applied magnetic field. We here discuss the results on the field and angular dependence of the magnetic response in zero field cooled magnetization experiments at low fields.
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| 5. |
- NISKANEN, K, et al.
(författare)
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ANISOTROPY IN SINGLE CRYSTALLINE BISRCACUO
- 1992
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Ingår i: Superconductors Science and Technology. - 0953-2048 .- 1361-6668. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- The longitudinal component of the magnetization of a single crystal of Bi2.2Sr1.7CaCu2O8 has been investigated by SQUID-magnetometry when the magnetic field is applied at different angles 0-degrees-90-degrees with respect to the crystallographic c-axis. The anisotropy of the system, deduced from the magnetization and relaxation rate data, indicates a mass anisotropy m(c)/m(ab) of order 20, a strikingly low value compared to what has been found from torque and magnetoresistance measurements m(c)/m(ab) almost-equal-to 3000.
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| 6. |
- NISKANEN, K, et al.
(författare)
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NONLOGARITHMIC MAGNETIC-RELAXATION IN BI-SR-CA-CU-O SINGLE-CRYSTALS
- 1991
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Ingår i: Superconductors Science and Technology. - 0953-2048 .- 1361-6668. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The time dependence of the low field susceptibility of a Bi2.2Sr1.7CaCu2O8 single crystal has been investigated in the field range 0.1-300 gauss and at temperatures 0.25 less-than-or-equal-to T/T(c) less-than-or-equal-to 0.9. The relaxation of the magnetization is found to change from a logarithmic to a non-logarithmic form as the applied field is increased, implying that a conventional flux creep model cannot sufficiently describe the behaviour.
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| 7. |
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| 8. |
- Permadi, H, et al.
(författare)
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Effects of perfluoro fatty acids on peroxisome proliferation and mitochondrial size in mouse liver : dose and time factors and effect of chain length.
- 1993
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Ingår i: Xenobiotica. - 0049-8254 .- 1366-5928. ; 23:7
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Tidskriftsartikel (refereegranskat)abstract
- 1. Male mice were fed a diet containing perfluoro fatty acids of varying chain length (i.e. perfluoroacetic, -butyric, -octanoic and -decanoic acids) at different doses (0.02 or 0.1% w/w of diet) for different periods of time (2-10 days), and effects on liver weight, hepatic mitochondrial protein and hepatic peroxisomal palmitoyl-CoA oxidation, lauroyl-CoA oxidase and catalase were monitored. 2. The greatest effects were obtained with perfluoro-octanoic and perfluoro decanoic acids, while perfluoro acetic acid was inactive. The effects with 0.02% w/w of diet perfluoro-octanoic acid were at least as great as those observed with 0.1%. A more detailed dose-response investigation focused on perfluoro-octanoic acid revealed that maximal effects with this substance could be obtained with a dietary dose of 0.01% for 10 days and that significant changes were also observed with 0.001%. 3. Maximal effects with 0.02% w/w of diet perfluoro-octanoic acid were attained after 6-10 days of feeding. 4. As with other peroxisome proliferators, perfluoro fatty acids increase mouse hepatic peroxisomal fatty acid beta-oxidation more extensively than they increase catalase, thus increasing hepatic oxidative stress. 5. As with other peroxisome proliferators, perfluoro fatty acids increase mouse liver mitochondrial protein. This effect is due primarily to a redistribution of mitochondria from the nuclear to the mitochondrial fraction, caused by an apparent decrease in the mean size of hepatic mitochondria after treatment.
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| 9. |
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| 10. |
- SVEDLINDH, P, et al.
(författare)
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MAGNETIC-RELAXATION IN AN ISOTROPIC EXTREME TYPE-II SUPERCONDUCTOR
- 1991
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 43, s. 2735-2741
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Tidskriftsartikel (refereegranskat)abstract
- The time dependence of the zero-field-cooled and thermoremanent magnetization of the isotropic extreme type-II superconductor PbMo6S8 has been measured at temperatures 0.7 less-than-or-equal-to T/T(c) less-than-or-equal-to 0.95 and for fields 1 less-than-or-equal-to H less-than-or-equal-to 300 G. The results show that the time dependence of the decay can be divided into three different field regimes: (1) A low-field regime with a closely logarithmic decay and a well-established critical state. The relaxation rate [partial M/partial ln(t)] increases as H-5 for the zero-field-cooled magnetization and as H-2.4 for the thermoremanent magnetization. The reduction in magnetization over 5 decades in time (0.3-3 X 10(4) s) is, at most, a few percent. (2) A crossover-field regime with a change from a logarithmic to a nonlogarithmic decay. (3) A high-field regime where the time dependence of the decay is well described by the expression delta-M approximately [ln(t/tau-0)]-alpha. The reduction in magnetization in the crossover- and high-field regimes is as large as 25-30% in the measured time interval. The results in the high-field regime are interpreted within the theory of collective flux creep. Comparisons are made with the magnetic relaxation found in anisotropic high-T(c) superconductors.
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| 11. |
- SVEDLINDH, P, et al.
(författare)
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NONLOGARITHMIC MAGNETIC-RELAXATION IN BI2.2SR1.7CACU2O8 SINGLE-CRYSTALS - EVIDENCE FOR COLLECTIVE FLUX PINNING
- 1991
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Ingår i: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 176, s. 336-346
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Tidskriftsartikel (refereegranskat)abstract
- High precision magnetic relaxation measurements have been performed on BiSrCaCuO single crystals with the field H applied parallel to the c-axis. At temperatures T/T(c) > 0.5, the data exhibit two different field regimes. One for H < H* (H* corresponds to the field where full flux penetration of the sample is achieved) where the ZFC and RM magnetization relaxes logarithmically with time in agreement with the conventional flux creep model; a second one for H > H* where the relaxation follows a [ln(t/t0)]-alpha dependence. This relaxation law is predicted in the collective flux creep theory for J << J(c) as well as in the vortex-glass model. In the temperature range 0.25 < T/T(c) < 0.4, there is a change in character of the measured decay of the magnetization. This change in character is interpreted to arise from thermal fluctuations of the flux-line lattice giving rise to a considerable reduction in the pinning strength above the depinning temperature.
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