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- Clyne, N, et al.
(författare)
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The intracellular distribution of cobalt in exposed and unexposed rat myocardium
- 1990
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - 0036-5513 .- 1502-7686. ; 50:6, s. 605-609
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Tidskriftsartikel (refereegranskat)abstract
- The intracellular distribution of cobalt was analysed in the myocardium of exposed and unexposed rats. The exposed rats were given a dietary cobalt supplementation of 40 mg CoS04-7 H20/kg body weight for 8 weeks. The mitochondrial fraction showed the greatest relative increase in cobalt: 0.09 ng/mg protein in the unexposed rats to 8.43 ng/mg protein in the exposed rats. In the exposed rats the submitochondrial particles had the highest levels of cobalt: 19.43 ng/mg protein, followed by the sarcoplasmatic reticulum: 12.3 ng/mg protein. The microsomal 44 000g supernatant also showed an increase, although the levels remained low (0.51 ng/mg protein in the exposed animals). Apparently the calcium-storing organelles had the highest levels of cobalt. This could affect calcium flux in myocardial cells and, secondarily, tension development in cardiac muscle.
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| 4. |
- Ni, W.-X., et al.
(författare)
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δ-function-shaped Sb-doping profiles in Si(001) obtained using a low-energy accelerated-ion source during molecular-beam epitaxy
- 1992
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Ingår i: Physical Review B. - 0163-1829. ; 46:12, s. 7551-7558
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) buried delta-function-shaped Sb-doping profiles have been obtained in Si using a low-energy accelerated Sb-ion source during molecular-beam epitaxy. A combination of secondary-ion mass spectrometry (SIMS), capacitance-voltage (C-V) measurements, and cross-sectional transmission electron microscopy (XTEM) was used to investigate dopant distributions and to determine profile widths. The 2D-sheet Sb-doping concentration N(Sb), obtained by integrating SIMS delta-doping profiles in samples grown with substrate temperature T(s) = 620-degrees-C and Sb-ion acceleration potentials V(Sb) = 200 and 300 V, was found to vary linearly with the product of the Sb-ion flux and the exposure time (i.e., the ion dose) over the N(Sb) range from 5 X 10(12) to 2 X 10(14) cm-2. The full width at half maximum (FWHM) concentration of 8-doping profiles in Si(001) films was less than the depth resolution of both SIMS and C-V measurements (approximately 10 and 3 nm, respectively). High-resolution XTEM lattice images show that the FWHM was less-than-or-equal-to 2 nm. This is consistent with dopant incorporation simulations, based upon a multisite transition-state dopant incorporation model, which show that accelerated-beam dopant species are trapped in near-surface substitutional sites with atomic mobilities between those of surface and bulk atoms. Dopant surface segregation during growth is strongly suppressed, and the dopant distribution is determined primarily by the straggle in ion trapping distributions. The present results are compared with profile broadening observed in 8-doped layers obtained by solid-phase epitaxy of amorphous Si containing a buried Sb layer.
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- Borowiec, Jan, et al.
(författare)
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Decreased blood loss after cardiopulmonary bypass using heparin-coated circuit and 50% reduction of heparin dose
- 1992
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Ingår i: Scandinavian journal of thoracic and cardiovascular surgery. - 0036-5580. ; 26:3, s. 177-185
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Tidskriftsartikel (refereegranskat)abstract
- In a randomized, double-blind study of patients undergoing elective coronary artery grafting, the effect of heparin-coated circuit combined with 50% reduction of systemic heparin bolus was investigated. Ten patients comprised group HC (heparin-coated) and ten group C (controls). The mean total doses of heparin were 172 IU/kg in group HC and 416 IU/kg in group C and the respective protamine doses were 0.96 and 3.96 mg/kg (both p < 0.001). Activated clotting times during cardiopulmonary bypass were significantly shorter in group HC, and both intra- and postoperative bleeding was significantly less than in group C (7.7 vs. 11.7 ml/kg, p = 0.036, and 6.9 vs. 9.7 ml/kg, p = 0.004). Hemoglobin loss via the drains was 22.5 g in group HC and 43.7 g in group C (p < 0.005). Hemolysis at the end of bypass was significantly greater in group C. Apart from one perioperative myocardial infarction in group HC the postoperative course was uneventful. Use of a heparin-coated circuit is concluded to permit complication-free reduction of heparin and protamine doses and to decrease both intra- and postoperative bleeding, which may favorably influence the outcome of coronary artery grafting.
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- Håkansson, G., et al.
(författare)
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Ion irradiation effects during growth of Mo/V(001) superlattices by dual-target magnetron sputtering
- 1992
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 121:3, s. 399-412
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial (001)-oriented Mo/V superlattice films with wavelengths of ≈ 5 nm have been grown on MgO(001) substrates, kept at 700°C, by dual-target unbalanced magnetron sputter deposition in Ar discharges. Low-energy (15-250 eV) Ar ion irradiation with incident ion-to-metal flux ratio of ≈ 1 during film growth was obtained through the application of a negative potential Vs to the substrate. The effects of ion bombardment on interface roughness and mixing, resputtering rates, and defect structure were investigated using a combination of cross-sectional transmission electron microscopy (XTEM), X-ray diffraction (XRD), and simulation of XRD patterns. High-resolution XTEM images showed that the interfaces were relatively sharp for Vs ≤ 100 V while higher Vs values resulted in more diffuse interfaces indicating ion-induced intermixing. By using a kinematical model of diffraction, and comparing with experimental XRD results, it could be concluded that the intermixing increased from ≈ 0.3 nm (2 monolayers) at Vs = 15 V to & 0.9 nm (6 monolayers) at Vs = 250 V. The inhomogeneous strain showed a large increase for Vs & 50 V. This is explained by an incorporation of point defects. Coherency strain relaxation between layers is suggested to take place through the formation of edge dislocations with Burgers vector 〈110〉 by climb processes. Finally, increasing Vs also resulted in resputtering, preferentially from the V layers.
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| 7. |
- Sjostrom, H., et al.
(författare)
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Characterization of interfaces between hydrogenated amorphous carbon films and steel substrates using high resolution cross-sectional transmission electron microscopy
- 1993
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Ingår i: Diamond and Related Materials. - 0925-9635. ; 2:2-4, s. 562-566
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Tidskriftsartikel (refereegranskat)abstract
- Cross-sectional transmission electron microscopy, including high resolution microscopy, was employed to characterize the interfaces between hydrogenated amorphous carbon (a-C:H) films and steel substrates. Films were deposited both by ion beam decomposition of large hydrocarbon molecules and by magnetron plasma decomposition of C2H2. The latter method was also used to deposit Mo- and W-containing a-C:H films onto steel substrates with interlayers of the pure metals between the steel substrate and the a-C:H films. The films were found to be amorphous except for the metal-containing films where 1–4 nm crystalline clusters were present in an a-C:H matrix. The metal interlayers had a columnar microstructure with column widths of ∼30 nm. The interfaces between the a-C:H films and the Mo or W interlayers were found to extend over 20–40 nm with a gradual crystalline-to-amorphous transition. In most of the a-C:H film-substrate interface regions a thin (less than 10 nm) layer was observed which was predominantly amorphous, but contained a small fraction of crystalline grains. Additional analyses carried out using Auger electron spectroscopy showed an increase in both O and N close to the interface. However, for the cases with Mo and W interlayers, the substrate surface contaminants were less localized and on some parts of the substrate surface the lattice fringes were continuous across the atomically sharp interface.
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