| 1. |
- Andersson, A, et al.
(författare)
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White spot lesion regression with the CPP-ACP system assessed by a laser fluorescence device (DIAGNOdent).
- 2006
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Ingår i: Oral Health Prev Dent.
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate and compare the effects of a dental cream containing complexes of casein phosphoprotein-amorphous calcium phosphate (CPP-ACP) and fluoride mouth rinses on the regression of white spot lesions (WSL). Material and methods: The study group consisted of 26 healthy adolescents (mean age 14.6 yr) exhibiting 60 teeth with 152 visible WSL sites on incisors and canines immediately after debonding of fixed orthodontic appliances. After bracket removal, professional tooth cleaning and drying, a visual scoring (0-4) and laser fluorescence (LF) readings were carried out. The patients were randomly assigned to two different treatment protocols with the aim to remineralize the lesions: A) daily topical applications of a dental cream containing CPP-ACP (Topacal) for 3 months followed by a 3-month period of daily tooth brushing with fluoridated toothpaste, or B) daily 0.05% sodium fluoride rinses combined with fluoridated toothpaste for 6 months. The registrations were repeated after 1, 3, 6 and 12 months and follow-up data were compared with baseline with aid of chi-square and paired t-tests. Results: A significant improvement of the clinical WSL-scores was found over time in both groups but there was a statistically significant difference (p<0.01) concerning the number of sites that totally disappeared after 12 months in favor for the CPP-ACP regime, 63% vs. 25% respectively. The clinical registrations were mirrored by a statistically significant decrease (p<0.05) in the LF readings at the 6- and 12-month follow-ups compared to baseline. No significant differences were displayed between the groups. Conclusion: Clinical scoring and LF assessment suggested that both regimens could promote regression of WSL after debonding of fixed orthodontic appliances. The visual evaluation suggested an aesthetically more favourable outcome of the amorphous calcium phosphate treatments.
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| 2. |
- Anter, Karin Fridell, et al.
(författare)
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SYN-TES INTERDISCIPLINARY RESEARCH ON COLOUR AND LIGHT
- 2012
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Ingår i: Proceedings for Interim Meeting of the International Colour Association (AIC); AIC 2012 “In Color We Live: Color and Environment”, 22 – 25 September 2012, Taipei, Taiwan. - : The International Colour Association. ; , s. 80-83, s. 80-83
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Konferensbidrag (refereegranskat)abstract
- Colour and light have largely been considered as belonging to two different fields of knowledge, having disparate theoretical, terminological and methodological traditions. This creates a ground for misunderstandings and obstructs a fruitful interdisciplinary and interprofessional collaboration. A survey over international research literature from 2006 -2011 shows that there has been only little research on the spatial interaction between colour and light, but that the interest for this area has recently increased. The interdisciplinary Nordic research project SYN-TES: Human colour and light synthesis. Towards a coherent field of knowledge was carried out during 2010-11. Colour and light experts from Nordic universities and companies investigated different aspects of the spatial interaction between colour and light and its importance for human beings. This paper deals with the general learnings from the process. Specific results are presented in other papers at this conference.
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| 3. |
- Backström, Tobias, et al.
(författare)
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CRF and urotensin I effects on aggression and anxiety-like behavior in rainbow trout
- 2011
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 214:6, s. 907-914
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Tidskriftsartikel (refereegranskat)abstract
- Corticotropin-releasing factor (CRF) is central in the stress response but also modulates several behaviors including anxiety-related behaviors and aggression. In this study, juvenile rainbow trout (Oncorhynchus mykiss) were tested for competitive ability, determined during dyadic fights for dominance, after intracerebroventricular (i.c.v.) administration of CRF, urotensin I (UI), the non-specific CRF antagonist alpha-helical RF9-41 (ahCRF) or the CRF receptor subtype 1-specific antagonist antalarmin, when paired with a mass-matched con-specific injected with saline. In addition, isolated fish received the same substances. Plasma cortisol and brain monoamines were monitored in all fish. Most fish receiving CRF showed a conspicuous behavior consisting of flaring the opercula, opening the mouth and violent shaking of the head from side to side. When this occurred, the fish immediately forfeited the fight. Similar behavior was observed in most fish receiving UI but no effect on outcome of dyadic fights was noted. This behavior seems similar to non-ambulatory motor activity seen in rats and could be anxiety related. Furthermore, fish receiving CRF at a dose of 1000. ng became subordinate, whereas all other treatments had no effects on the outcome of dyadic fights. In addition, isolated fish receiving ahCRF had lower brain stem concentrations of 5-hydroxyindoleacetic acid, serotonin, 3,4-dihydroxyphenylacetic acid and dopamine. In conclusion, CRF seems to attenuate competitive ability, and both CRF and UI seem to induce anxiety-like behavior.
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| 4. |
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| 5. |
- Björklund, Svante, et al.
(författare)
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A three-dimensional displaced phase center antenna condition for clutter cancellation
- 2014
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Ingår i: Proceedings of the IEEE Sensor Array and Multichannel Signal Processing Workshop. - : IEEE. - 9781479914814 ; , s. 305-308
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Konferensbidrag (refereegranskat)abstract
- In moving radar, e.g. airborne radar, the clutter from land and sea needs to be suppressed in order to detect the target. One approach to total cancellation of the clutter is Displaced Phase Center Antenna (DPCA). DPCA assumes that the antenna elements are positioned on a line parallel to the velocity vector of the radar platform so that the elements can take each others positions at different points of times. This paper theoretically investigates if it is possible with other antenna element positions, e.g. in three dimensions, for a total cancellation of the clutter. We arrive at a condition which conforms to the principle that the elements should take each others positions at different times but allows other antennas than the single line parallel to the velocity vector. Our condition could be used as constraints in an optimization problem where the target signal performance is optimized. The multipulse DPCA condition is one solution to our condition.We also give two examples of non-linear antennas fulfilling our condition.
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| 6. |
- Björklund, Svante, et al.
(författare)
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Auxiliary beam terrain-scattered interference suppression : reflection system and radar performance
- 2013
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Ingår i: IET Radar, Sonar & Navigation. - : The Institution of Engineering and Technology (IET). - 1751-8784 .- 1751-8792. ; 7:8, s. 836-847
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Tidskriftsartikel (refereegranskat)abstract
- Terrain-scattered interference (TSI), that is, jammer signals reflected on the earth's surface, is a significant problem to military airborne radar. In auxiliary beam TSI suppression, the TSI in the main radar beam is estimated by a single or several auxiliary beams and is subtracted from the main beam channel. The signal to subtract is the auxiliary beam signals fed through an estimate of the ‘reflection system’, which describes scattering on the surface. The authors first present results on the structure of this TSI suppression, on the estimation of the reflection system and on the quality of the estimate. Then the authors derive theoretical expressions for the signal-to-interference plus noise ratio (SINR) and the remaining TSI power for a single auxiliary beam. Since the SINR is directly connected to the radar performance, it can be seen what factors affect the performance and how. It was noted that when the estimated reflection system is missing one or more delays of the true system, the TSI filter cannot suppress the TSI signal completely. This phenomenon, which is called ‘TSI leakage’, has a very large impact on the performance. The SINR cannot be kept constant. Instead, an ‘SINR improvement’ can be defined.
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| 7. |
- Björklund, Svante, et al.
(författare)
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Factors Affecting the Effective Clutter Rank for Planar and Conformal Antennas with Subarrays
- 2023
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Ingår i: Proceedings of the IEEE Radar Conference 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- The Effective Clutter Rank (ECR), the number of eigenvalues of the clutter covariance matrix larger than the white noise, has important consequences for the radar system when suppressing clutter with Space-Time Adaptive Processing (STAP), in terms of cost, complexity, usability and performance. In this paper some factors affecting the ECR are studied by simulations. The result is partly explained by theory from the literature. The main results are: 1) Factors affecting the ECR [subarray beam pointing direction, subarray design, antenna geometry, # radar pulses, PRF, radar velocity and target range]. 2) Differences between planar and conformal antennas. 3) A simulation-based rank calculation method for antennas with subarrays.
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| 8. |
- Björklund, Svante, et al.
(författare)
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Fast-Time and Slow-Time Space-Time Adaptive Processing for Bistatic Radar Interference Suppression
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL RADAR CONFERENCE (RADARCON). - : IEEE Communications Society. - 9781479982325 ; , s. 674-678
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Konferensbidrag (refereegranskat)abstract
- In bistatic radar with transmitter and receiver geographically separated the interference from ground clutter and the direct path signal transmitter-receiver will be strong and must be suppressed in order to detect the target. We apply FT-STAP (Fast-Time Space Time Adaptive Processing) to the suppression, which is unusual, and compare with conventional ST-STAP (Slow-Time STAP) by simulations in order to see whether FT-STAP is an alternative to ST-STAP. The performance of FT-STAP is much worse than of ST-STAP. We give an explanation for this, which also may be the basis for large improvements of FT-STAP. Moreover, we suggest two new performance measures.
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| 9. |
- Björklund, Svante, et al.
(författare)
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Measurement of Rank and Other Properties of Direct and Scattered Signals
- 2016
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Ingår i: International Journal of Antennas and Propagation. - : Hindawi Publishing Corporation. - 1687-5869 .- 1687-5877. ; 2016
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Tidskriftsartikel (refereegranskat)abstract
- We have designed an experiment for low-cost indoor measurements of rank and other properties of direct and scattered signals with radar interference suppression in mind. The signal rank is important also in many other applications, for example, DOA (Direction of Arrival) estimation, estimation of the number of and location of transmitters in electronic warfare, and increasing the capacity in wireless communications. In real radar applications, such measurements can be very expensive, for example, involving airborne radars with array antennas. We have performed the measurements in an anechoic chamber with several transmitters, a receiving array antenna, and a moving reflector. Our experiment takes several aspects into account: transmitted signals with different correlation, decorrelation of the signals during the acquisition interval, covariance matrix estimation, noise eigenvalue spread, calibration, near-field compensation, scattering in a rough surface, and good control of the influencing factors. With our measurements we have observed rank, DOA spectrum, and eigenpatterns of direct and scattered signals. The agreement of our measured properties with theoretic and simulated results in the literature shows that our experiment is realistic and sound. The detailed description of our experiment could serve as help for conducting other well-controlled experiments. © Copyright 2016 Svante Björklund et al.
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| 10. |
- Björklund, Svante, et al.
(författare)
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Radar-Like Measurements with an Experimental Digital Beamforming Array Antenna
- 1998
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Konferensbidrag (refereegranskat)abstract
- An experimental S-band digital beamforming receiving array antenna has been used in “radar- like” measurements, where radar signals with programmable waveforms are transmitted. The measurements are carried out in an anechoic chamber and the measured signals come from the direct path from transmitter antennas to the receiver antenna. In this way targets are simulated. On the received signals, conventional beamforming, pulse compression, doppler filtering and high resolution direction of arrival estimation are performed. Accurate channel calibration and channel equalization are utilized. This paper first describes the receiving antenna, transmitter control, measurement arrangements, calibration and signal processing. It then presents some measurement results for high resolution direction of arrival estimation and for radar resolution of one and two targets.
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