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- Persson, Bertil
(författare)
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Psykologisk migränforskning
- 1987
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Ingår i: Nordisk Psykologi: Teori, Forskning, Praksis. - 0029-1463. ; 39:3, s. 228-232
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Tidskriftsartikel (refereegranskat)abstract
- Migrängruppen bestod av 28 migräniker (17 kvinnor och 11 män) som slumpvist drogs på neurologiska kliniken, Lund. Medelåldern var 31 år. Kontrollgruppen bestod av 28 personer (14 kvinnor och 14 män) som slumpvist drogs ur telefonkatalogen över Lund, Eslöv, Malmö och Höör-områdena. Båda gruppernas medlemmar fick ett formulär hemskickat som besvarades och returnerades. Formuläret bestod av diagnostiska frågor för få migrändiagnosen bekräftad och frågor beträffande uppfostran. 68% hade upplevt en känslokall uppfostran i avsaknad av beröm, kramar och kyssar från föräldrarna, 61% hade upplevt en sträng uppfostran med både fysisk och psykisk aga. Om man blott betraktar de två första variablerna om aga och känslokyla så finner man att hela 78,6% i migrängruppen hade upplevt aga och/eller känslokyla mot 42,8% i kontrollgruppen )p=.001).
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| 6. |
- Samuelsson, Christer, et al.
(författare)
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222Rn and 210Pb in the Arctic summer air
- 1986
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Ingår i: Journal of Environmental Radioactivity. - 0265-931X. ; 3:1, s. 35-54
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Tidskriftsartikel (refereegranskat)abstract
- As part of an extensive air chemistry programme, during summer 1980, on board the Swedish ice-breaker 'Ymer', levels of 222Rn (radon) and its long-lived daughters 210Pb and 210Po were measured. The radon was trapped on charcoal and the long-lived daugther products sampled on filters on a daily basis. In addition, short-lived progenies were followed continuously on the filters in order to achieve a time resolution of about one hour. The concentrations of radon and 210Pb in the Arctic summer air north of latitude 75° N averaged 75 ± 21 (1 sd) and 0·075 ± 0·028 mBqm-3, r respectively. During a two week period of persistent polar winds, the mean radon concentration was 19 ±5 mBq m-3. During such 'Arctic background' conditions, radon exhalation from the sea may contribute significantly to the measured radon-in-air concentration. It is shown that steady-state equilibrium models, applied to an air mass over the sea, overstimate the aerosol residence-time calculated from activity ratios. Time-dependent calculations indicate a mean aerosol residence time of 4 to 7 d in Arctic air. Good agreement is observed between radon levels and the time since the air mass left larger areas. Both the 222Rn and the long-lived daughter measurements are insensitive to contamination from ship and local settlement.
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| 7. |
- Ståhlberg, Freddy, et al.
(författare)
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A method for MR quantification of flow velocities in blood and CSF using interleaved gradient-echo pulse sequences
- 1989
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Ingår i: Magnetic Resonance Imaging. - 0730-725X. ; 7:6, s. 655-667
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to establish a rapid method for in vivo quantification of a large range of flow velocities using phase information. A basic gradient-echo sequence was constructed, in which flow was encoded along the slice selection direction by variation of the amplitude of a bipolar gradient without changes in sequence timings. The influence of field inhomogeneities and eddy currents was studied in a 1.5 T scanner. From the basic sequence, interleaved sequences for calibration and in vivo flow determination were constructed, and flow information was obtained by pairwise subtraction of velocity-encoded from velocity non-encoded phase images. Calibration was performed in a nongated mode using flow phantoms, and the results were compared with theoretically calculated encoding efficiencies. In vivo flow was studied in healthy volunteers in three different areas using cardiac gating; central blood flow in the great thoracic vessels, peripheral blood flow in the popliteal vessels, and flow of cerebrospinal fluid (CSF) in the cerebral aqueduct. The results show good agreement with results obtained with other techniques. The proposed method for flow determination was shown to be rapid and flexible, and we thus conclude that it seems well suited for routine clinical MR examinations.
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| 8. |
- Ståhlberg, Freddy, et al.
(författare)
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Quantitative study of flow dependence in NMR images at low flow velocities
- 1986
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Ingår i: Journal of Computer Assisted Tomography. - : Ovid Technologies (Wolters Kluwer Health). - 0363-8715. ; 10:6, s. 1006-1015
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Tidskriftsartikel (refereegranskat)abstract
- A basic theoretical model that describes the effects of flow in and out of the imaging plane in nuclear magnetic resonance (NMR) images, obtained with the standard pulse sequences single spin echo, multiple spin echo, and inversion recovery, is presented. Theoretically calculated signal values are compared with experimental results obtained from single-slice images of a flow phantom for variable flow velocity v as well as for variable echo time and inversion time at flow velocities <10 mm/s, corresponding to those found in cerebrospinal fluid, in capillary systems, and in smaller veins. The quantitative correspondence between theory and experiment is good in the range of velocities studied and for the imaging parameters used, but discrepancies occur when higher velocities are studied. In addition, flow in a capillary model is demonstrated qualitatively for very low linear flow velocities, <1 mm/s. It is concluded that the model describes the essentials of the inflow-outflow effect and that this effect can predict the flow dependence of the NMR signal for low flow velocities. Observed differences between model and experiment may be due to effects of flow-induced phase alterations and due to uncertainty in measurements of the relaxation times T1 and T2. The model described here can be extended to suit other types of pulse sequences and to suit multislice imaging. It can also be extended to incorporate flow-induced phase effects.
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