| 1. |
- Axelsson, Anders, et al.
(författare)
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Determination of effective diffusion coefficients in calcium alginate gel plates with varying yeast cell content
- 1988
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Ingår i: Applied Biochemistry and Biotechnology. - 1559-0291. ; 18, s. 231-250
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Tidskriftsartikel (refereegranskat)abstract
- Effective diffusion coefficients (De) have been determined for lactose, glucose, galactose, and ethanol in calcium alginate gel with varying yeast cell concentration. The measurements have been performed in a diffusion cell, and the results evaluated with the quasisteady-state method. An ultrasonic meter was used for gel thickness determination with an accuracy of 1.5% and a new method for the reproducible preparation of gel plates was developed. It was found thatD e in pure alginate gel decreased to about 90% of the diffusivity in water and did not vary with alginate concentration.D e decreased considerably with increasing yeast cell concentration. For the solutes studied, the effective diffusion coefficient can be estimated according to the equationD e =D eo (1 - ϕ)/[1+(ϕ/2)], whereD eo is the effective diffusivity in pure gel and ϕ is the volume fraction of yeast cells.
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| 2. |
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| 3. |
- Bergstrom, H, et al.
(författare)
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Two different types of hollow-cathode discharges used for high resolution laser spectroscopy on copper
- 1989
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 13:3, s. 203-206
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Tidskriftsartikel (refereegranskat)abstract
- Two different techniques, Doppler-free saturation spectroscopy on a hollow-cathode discharge and fluorescence spectroscopy on a collimated atomic beam produced from a hollow-cathode discharge, have been used for high-resolution laser-spectroscopy measurements on the 3d10 4p and 5p states in neutral Copper. The relative merits of the two techniques are discussed.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Kröll, Stefan, et al.
(författare)
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Time-resolved laser spectroscopy on high-lying states in neutral oxygen
- 1985
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Ingår i: Physical Review Letters. - 1079-7114. ; 55:3, s. 284-287
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes have been measured for five triplet states of atomic oxygen. The oxygen atoms were generated by photodissociation of NO2 and the investigated states were populated through a two-step process involving a two-photon excitation to the lowest excited triplet state of even parity, 2p33p 3P, followed by a one-photon excitation to the investigated state. A similar scheme is applicable to the study of excited states in many light atoms.
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| 9. |
- Larsson, Hans, et al.
(författare)
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Studies on blood viscosity during the menstrual cycle and in the postmenopausal period in healthy women
- 1989
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - 0001-6349 .- 1600-0412. ; 68, s. 483-486
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Blood viscosity was measured in 14 healthy, menstruating women, aged 17-51 years and in 10 healthy, postmenopausal women, aged 55-64 years. The fertile women were studied once a week during a normal menstrual cycle and the postmenopausal women twice with an interval of 2 weeks. Blood viscosity was measured at natural hematocrit as well as at hematocrit 45%. In the postmenopausal women no changes in blood viscosity were found. In the fertile women, blood viscosity at hematocrit 45% was lowest at the start of the menstrual bleeding and increased to a peak at day 7 (p < 0.01), with a similar pattern when measured at natural hematocrit. Plasma viscosity also had its lowest value at the onset of menstrual bleeding, increasing to a maximum at day 21. Changes in plasma triglycerides, but not in fibrinogen or cholesterol, seemed to contribute to this increase. Plasma factors only partly explained the variations in blood viscosity, and changes in red cell properties were also found to be of importance. The clinical significance of these rheological changes remains to be established, but at least theoretically there may be an increased risk for thromboembolism, e.g. at surgery, during days 5-15 of the cycle. In studies on blood flow and rheological conditions in fertile women, it seems advisable to standardize for time in the menstrual cycle.
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| 10. |
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