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- Larsson Wexell, Cecilia, 1965, et al.
(författare)
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Bone response to surface modified titanium implants: studies on electropolished implants with different oxide thicknesses and morphology.
- 1994
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Ingår i: Biomaterials. - 0142-9612. ; 15:13, s. 1062-74
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Tidskriftsartikel (refereegranskat)abstract
- In a series of experimental studies, bone formation was analysed around systematically modified titanium implants. In the present study, machined, electropolished and anodically oxidized implants were prepared, surface characterized and inserted in the cortical bone of rabbits (7 wks and 12 wks). SEM, scanning Auger electron spectroscopy and atomic force microscopy revealed no differences in surface composition but marked differences in oxide thickness, surface topography and roughness. Light microscopic morphology and morphometry showed that all implants were in contact with bone, and had a large proportion of bone within the threads. The smooth, electropolished implants were surrounded by less bone than the machined implants with similar oxide thickness, (4-5 nm) and the anodically oxidized implants with thicker oxides (21 nm and 180 nm, respectively) after 7 wks. These studies show that a high degree of bone contact and bone formation can be achieved with titanium implants which are modified with respect to oxide thickness and surface topography. However, it appears that a reduction of surface roughness may influence the rate of bone formation in rabbit cortical bone.
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| 2. |
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| 3. |
- Nilsson, C, et al.
(författare)
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Circadian variation in human cerebrospinal fluid production measured by magnetic resonance imaging
- 1992
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Ingår i: American Journal of Physiology: Regulatory, Integrative and Comparative Physiology. - 1522-1490. ; 262:1, s. 20-24
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in magnetic resonance imaging have made it possible to visualize and quantify flow of cerebrospinal fluid (CSF) in the brain. The net flow of CSF through the cerebral aqueduct was used to measure CSF production in six normal volunteers at different times during a 24-h period. CSF production varied greatly both intra- and interindividually. The average CSF production in each time interval showed a clear tendency to circadian variation, with a minimum production 30% of maximum values (12 +/- 7 ml/h) approximately 1800 h and a nightly peak production approximately 0200 h of 42 +/- 2 ml/h. The total CSF production during the whole 24-h period, calculated as an average of all measurements, was 650 ml for the whole group and 630 ml for repeated measurements in each time interval in one of the volunteers.
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| 4. |
- Thomsen, Carsten, et al.
(författare)
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Fourier analysis of cerebrospinal fluid flow velocities : MR imaging study
- 1990
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Ingår i: Radiology. - : Radiological Society of North America (RSNA). - 0033-8419 .- 1527-1315. ; 177:3, s. 659-665
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Tidskriftsartikel (refereegranskat)abstract
- An interleaved pseudocinematographic FLASH (fast low-angle shot) sequence with additional pulsed gradients for flow encoding was used to quantify cerebrospinal fluid (CSF) flow velocities and CSF production. Flow-dependent phase information was obtained by subtracting two differently encoded phase images. The phase information in the resultant image was converted to flow velocity with a calibration curve with the slope 26.5 radian · m-1 · sec. The velocity versus time function was Fourier transformed and a continuous curve was fitted to the measured data with use of the first three harmonics. The in vivo measurements showed a significant variation in flow velocities in the cerebral aqueduct (range, 6-51 mm/ sec). Calculated CSF production was in the range of 0.6-1.2 L/24 h. The present method gives valuable information about CSF hydrodynamics in an imaging time of less than 8 minutes.
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