| 1. |
- Nilsson, Martin, et al.
(författare)
-
Measurements of the Spatio-Temporal Polarization Characteristics of a Radio Channel at 1800 MHz
- 1999
-
Ingår i: Proceedings IEEE Vehicular Technology Conference. - : IEEE. ; , s. 386-391
-
Konferensbidrag (refereegranskat)abstract
- We present a combined measurement and analysis of the spatial, temporal, and polarisation characteristics of a 1800 MHz radio channel. The measurements were performed using a correlative channel sounder. A complex chirp signal with a bandwidth of 150 MHz was transmitted by a vertically polarized omnidirectional antenna and received by a 8+8 dual polarized planar antenna array. Measurements were taken at two different base station locations, one being suburban and the other urban. Using this data we characterize the radio channel in terms of azimuth and delay spread of the vertical and horizontal polarization.
|
|
| 2. |
- Abdel-Motal, Ussama M., et al.
(författare)
-
Major histocompatibility complex class I binding glycopeptides for the estimation of 'empty' class I molecules
- 1995
-
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 188:1, s. 21-31
-
Tidskriftsartikel (refereegranskat)abstract
- Different forms of major histocompatibility complex (MHC) class I heavy chains are known to be expressed on the cell surface, including molecules which are functionally 'empty'. Direct peptide binding to cells is obvious during sensitization of target cells in vitro for cytotoxic T lymphocyte killing and 'empty' MHC-I molecules are comparatively abundant on TAP- 1 2 peptide transporter mutant cells. In the present work we have estimated the fraction of 'empty' MHC class I molecules using glycosylated peptides and cellular staining with carbohydrate specific monoclonal antibodies. Synthetic Db and Kb binding peptides were coupled at different positions with different di- or trisaccharides, using different spacing between the carbohydrate and the peptide backbone. Binding of sugar specific mAbs was compared in ELISA and cellular assays. An optimal Db binding glycopeptide was used for comparative staining with anti-Db and anti-carbohydrate monoclonal antibodies to estimate fractions of 'empty' molecules on different T lymphoid cells. On activated normal T cells, a large fraction of Db molecules were found to be 'empty'. The functional cole of such 'empty' MHC class I molecules on T cells is presently unclear. However, on antigen presenting cells they might participate in the antigen presentation process.
|
|
| 3. |
- Adner, Mikael, et al.
(författare)
-
Upregulation of a non-ETA receptor in human arteries in vitro
- 1995
-
Ingår i: Journal of Cardiovascular Pharmacology. - 1533-4023. ; 26:Suppl. 3, s. 314-316
-
Tidskriftsartikel (refereegranskat)abstract
- Receptor turnover may be a crucial part in the physiology of endothelin (ET). Incubation of vessel segments could be a possible method to demonstrate this. The aim was to study contractile responses of human omental arteries to different ET agonists at various periods after incubation at 37 degrees C in 5% CO2 and air. The maximum effect (Emax; percentage of contraction to 60 mM K+ buffer solution) and the potency of ET-1 were unaltered (pD2 = 8.82 +/- 0.06). The selective ETB agonist IRL 1620 demonstrated a negligible Emax in nonincubated segments (2.4 +/- 0.9%). After only 1 day of incubation the Emax was 51 +/- 23%, and it reached 114 +/- 53% after 5 days. The pD2 of IRL 1620 was stable throughout the incubation time (7.23 +/- 0.08). ET-3 showed a moderate Emax in nonincubated segments (55 +/- 18%), with a pD2 of 6.68 +/- 0.24. However, subsequent incubation revealed an increase of pD2 to 8.60 +/- 0.20 on the fifth day. The maximum contraction increased to 206 +/- 44%; this is equal to the contraction obtained in paired experiments with ET-1 (215 +/- 18%). These findings indicate modulation of endothelin receptor expression after incubation of vessel segments, and suggest the gradual appearance of a non-ETA receptor.
|
|
| 4. |
- Arildsson, Mikael, 1967-, et al.
(författare)
-
Critical design parameters in laser Doppler perfusion imaging
- 1996
-
Ingår i: <em>Proc. SPIE</em> 2678. - : SPIE Proceedings Series. - 9780819420527 ; , s. 401-408
-
Konferensbidrag (refereegranskat)abstract
- Laser Doppler Perfusion Imaging (LDPI) is a method for visualization of tissue blood perfusion. A low power laser beam is used to step-wise scan a tissue area of interest and a perfusion estimate based on the backscattered, partially Doppler broadened, light is generated. Although the basic operating principle of LDPI is the same as that of conventional Laser Doppler Perfusion Monitoring (LDPM), significant differences exist between the implementation of the methods which must be taken into account in order to generate high quality perfusion images. The purpose of this study is to investigate the relevance of a number of LDPI design parameters, such as:(1) The influence of artifact noise when using a continuously moving laser beam instead of a step-wise moving beam to scan the image.(2) The signal processor output's dependency on the distance between the measurement object and the scanner head when using collimated laser light.(3) The speed and mode of the scanning.The results show a substantial rise in the noise level when using a continuously moving beam as opposed to a step-wise. Skin measurements using a collimated laser beam demonstrated an amplification factor dependency on the distance between the skin surface and the scanner head not present when using a divergent laser beam. The scanning speed is limited by the trade-off between the Doppler signal lower cut-off frequency and the image quality.
|
|
| 5. |
- Arildsson, Mikael, 1967-, et al.
(författare)
-
Higher order moment processing of laser Doppler perfusion signals
- 1997
-
Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 2:4, s. 358-363
-
Tidskriftsartikel (refereegranskat)abstract
- The laser Doppler technique is used to assess tissue perfusion. Traditionally an integrated, ω-weighted (first-order filter) power spectrum is used to estimate perfusion. In order to be able to obtain selective information about the flow in vessels with different blood cell velocities, higher order filters have been implemented, investigated, and evaluated. Theoretical considerations show that the output of the signal processor will depend on the flow speed, for a given concentration of blood cells, according to Sout∞νn where v is the average blood cell speed and n is the spectral filter order. An implementation of filters using zero-, first-, second-, and third-order spectral moments was utilized to experimentally verify the theory by using a laser Doppler perfusion imager. Two different flow models were utilized: A Plexiglas model was used to demonstrate the various signatures of the power spectrum for different flow speeds and filter orders, whereas a Delrin model was used to study the relationship between the flow velocity and the output of the signal processor for the different filters. The results show good agreement with theory and also good reproducibility. Recordings made on the skin of the wrist area demonstrated that the flow in small veins can be visualized by the use of higher spectral orders.
|
|
| 6. |
|
|
| 7. |
- Arvastson, Gösta, Lennartsson, Rebecka, Andersson, Maria, Zackariasson, Maria, Ljung, Anna , Ek-Nilsson, Katarina, Mebius, Anders, Vallström, Mikael
(författare)
-
Järnbur eller frigörelse.Studier i moderniseringen av Sverige.
- 1999
-
Bok (övrigt vetenskapligt/konstnärligt)
|
|
| 8. |
|
|
| 9. |
- Hansson, L, et al.
(författare)
-
Predictors of subjective quality of life in schizophrenic patients living in the community. A Nordic multicentre study.
- 1999
-
Ingår i: International Journal of Social Psychiatry. - 0020-7640 .- 1741-2854. ; 45:4, s. 247-58
-
Tidskriftsartikel (refereegranskat)abstract
- As part of a Nordic multi-centre study investigating the life and care situation of community samples of schizophrenic patients the aim of the present part of the study was to examine the relationship between global subjective quality of life and objective life conditions, clinical characteristics including psychopathology and number of needs for care, subjective factors such as satisfaction with different life domains, social network, and self-esteem. A sample of 418 persons with schizophrenia from 10 sites was used. The results of a final multiple regression analysis, explaining 52.3% of the variance, showed that five subjective factors were significantly associated with global subjective quality of life, together with one objective indicator, to have a close friend. No clinical characteristics were associated with global subjective quality of life. The largest part of the variance was explained by satisfaction with health, 36.3% of the variance, and self-esteem, 7.3% of the variance. It is concluded that the actual relationship between objective life conditions and subjectively experienced quality of life still remains unclear. Furthermore, it seems obvious that personality related factors such as self-esteem, mastery and sense of autonomy also play a role in the appraisal of subjective quality of life, which implies that factors like these are important to consider in clinical and social interventions for patients with schizophrenia in order to improve quality of life for these persons.
|
|
| 10. |
|
|
