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- Ahlberg, M., et al.
(författare)
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Downlink propagation measurements in the GSM 900 and 1800 MHz bands
- 1999
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Ingår i: IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010). ; , s. 1506-1509 vol.3
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Konferensbidrag (refereegranskat)abstract
- The authors investigate radio propagation in the GSM 900 and 1800 MHz bands in a typical Swedish suburban environment to determine whether or not it is practically feasible to co-site GSM 900 with GSM 1800 systems. They show that propagation in the GSM 1800 band is considerable higher (about 12 dB) than in the old GSM 900. In many cases this difference can be reduced by using dual band sector antennas with 3 dB higher gain at 1800 MHz. However, they also show that in small cells (radius <1000 m) this difference is of little concern and therefore it is possible to co-locate GSM 1800 sites within existing 900 MHz sites as a cost-effective way to increase the system capacity.
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| 3. |
- Beckman, Claes M. E., 1962
(författare)
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Studies in Physiological Optics and Microwave Hyperthermia
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the optics of the eye, the sky and microwave induced hyperthermia treatment of cancer. Light scattering in normal eyes is reviewed and its influence on vision is discussed in some detail. It is noted that artists usually take intraocularly scattered light into account when depicting scenes, and a photographic method to achieve similar effects is demonstrated. A new method for in vivo light scattering measurements in living rabbit eyes is presented and preliminary results are reported. Using both theoretical models and clinical measurements the importance of increased light scattering for retinal image quality is studied in cataractous eyes. In the analysis an assumed neural contrast sensitivity function is used, derived from results from previous investigations. The analysis shows that visual acuity is quite insensitive even to substantial diffusive scattering provided that glare sources are not present in the field of view. Different glare test methods are studied. A versatile and simple apparatus for clinical glare testing is constructed. It utilizes a flickering glare source and is optimized for maximum accuracy. A diffractive, bifocal intraocular lens is studied through computer simulation, optical bench measurements, and visual acuity testing. This lens combines a traditional intraocular lens with a blazed Fresnel lens structure on one of its surfaces, supposedly allowing the patient good distant as well as near vision. It is found that a pupil displacement of the order of 1 mm considerably reduces the lens' resolution. A possible side-effect of new headlights for cars, which utilize ultraviolet radiation, is intraocular stray-light increase, a study of which is reported. The widely held notion that the Vikings utilized polarization of skylight on overcast days for navigational purposes is demonstrated to have no scientific basis. A microwave applicator for intracavitary hyperthermia treatment of cancer is designed and tested. The applicator is a section of a dielectric-loaded circular ridge waveguide closed at both ends forming a transmission cavity. An aperture in the cavity wall produces a directed heating of a tumour growing in the wall of a body cavity such as the vagina.
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| 6. |
- Blomström-Lundqvist, C, et al.
(författare)
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Incessant ventricular tachycardia with a right bundle-branch block pattern and left axis deviation abolished by catheter manipulation
- 1990
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 13:1, s. 11-16
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Tidskriftsartikel (refereegranskat)abstract
- A 22-year-old man underwent electrophysiological evaluation for incessant wide QRS complex tachycardia with a pattern of right bundle-branch block and left axis deviation. The right and left ventricles were enlarged and hypokinetic consistent with dilated cardiomyopathy. Ventricular tachycardia was diagnosed by demonstrating capture and fusion beats, atrioventricular dissociation, and His potential activation that began after the onset of each QRS complex. Atrial extrastimuli and rapid atrial pacing failed to terminate the tachycardia and, although ventricular stimulation was successful, the tachycardia spontaneously restarted after one or two sinus beats. The tachycardia was unexpectedly abolished during catheter manipulation in the left ventricle and has not recurred during three-years of follow-up. The picture of a cardiomyopathy resolved. The ease with which the tachycardia was abolished by catheter manipulation implicate a therapeutic potential for catheter ablation of this type of tachycardia.
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| 7. |
- Dejongh, J, et al.
(författare)
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An Integrated Approach to the Prediction of Systemic Toxicity using Computer-based Biokinetic Models and Biological In vitro Test Methods : Overview of a Prevalidation Study Based on the ECITTS Project.
- 1999
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Ingår i: Toxicology in Vitro. - 0887-2333 .- 1879-3177. ; 13:4-5, s. 549-54
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Tidskriftsartikel (refereegranskat)abstract
- Chemical toxicity was estimated by integrating in vitro study results with physiologically-based biokinetic models for eight neurotoxic compounds (benzene, toluene, lindane, acrylamide, parathion/oxon, caffeine, diazepam and phenytoin). In vitro studies on general and specific neurotoxicity were performed and biotransformation and tissue-blood distribution studies were used in modelling the biokinetic behaviour of the compounds. Subsequently, neurotoxicity was estimated from the integrated in vitro and kinetic studies. These results were compared with in vivo data from the literature on minimal neurotoxicity for these compounds, such as lowest-observed-effect levels (LOELs). The discrepancy between estimated and experimental LOELs ranged from 2- to 10-fold. LOEL estimates for compounds with a relatively low toxicity were more accurate than for compounds with a relatively high toxicity. LOELs for the most active compounds could only be established after consideration of additional in vitro results from the literature. The present study has generated encouraging results on the risk assessment of chemicals from in vitro studies and computer simulations and has identified some key directions for future research.
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| 8. |
- Imreh, Gabriela, et al.
(författare)
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Noninvasive monitoring of apoptosis versus necrosis in a neuroblastoma cell line expressing a nuclear pore protein tagged with the green fluorescent protein
- 1998
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 238:2, s. 371-376
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Tidskriftsartikel (refereegranskat)abstract
- A fusion chimera between the integral nuclear pore membrane protein POM121 and GFP (green fluorescent protein) has been shown to correctly target to the nuclear pores when transiently expressed in a number of mammalian cell types. POM121-GFP is therefore an excellent marker for the noninvasive studies of the nuclear pores in living cells using fluorescence microscopy. We have established a line of neuroblastoma cells stably expressing the POM121-GFP fusion protein. We also monitored the nuclear envelope in living cells after induction of apoptosis or necrosis using 1 μM staurosporine or 100 μM p-benzoquinone, respectively. Interestingly, the POM121-GFP fluorescence was weaker or missing in the apoptotic cells. The disappearance of the nuclear pore marker accompanied apoptotic progression as judged by the degree of chromatin condensation and DNA fragmentation as analyzed by DNA staining and TUNEL assay, respectively. In contrast, the intensity of the nuclear rim fluorescence was unaffected in necrotic cells displaying an abnormal morphology with tilted nuclei. Thus, it was possible to distinguish between apoptotic and necrotic development in living cells using fluorescence microscopy. This cell line provides a fast and convenient model for screening suspected toxic xenobiotics.
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