| 1. |
- Alm Carlsson, Gudrun, et al.
(författare)
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Monte Carlo metoden : ett verktyg inom strålningsfysiken
- 1995
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta kompendium är tänkt att användas som ett propedeutiskt kursmaterial för kursdeltagare i kursen "Monte Carlo simulering av foton- och elektrontransport vid diagnostiska och radioterapeutiska strålkvaliteter". Först följer en kort repetition av den grundläggande statistik som utnyt1jas i beräkningarna. Därefter följer en beskrivning av slumptal. det fundament som metoden bygger på. Vidare beskrivs val ur olika frekvensfunktioner. Valet kan även göras ur så kallade falska fördelningar för att reducera variansen i den skattade storheten. Metoderna belyses i ett avsnitt om problemlösningsmetodik. först i allmänna termer för att sen gå in på ett specifikt problem (Buffons nålproblem) där en analys och strukturering av problemet görs varefter flödesschema och kodning exemplifieras. Så följer två moment där en beskrivning görs av färderna av fotoner respektive elektroner genom materia. För elektronfärderna gör man en indelning i klass 1- och klass II-färder. Vad detta innebär och hur deltapartiklar tas om hand beskrivs i ett kapitel. Till sist kommer en kort introduktion till de tre laborationerna med laborationshandledningar. Speciell vikt har lagts vid att initiera laboranten att fundera på fysiken i de simulerade experimenten. Detta kompendium har tillkommit som examinationsarbete vid en kurs i "Monte Carlo simulering av foton- och elektrontransport vid diagnostiska och radioterapeutiska strålkvaliteter", med andra ord den kurs du själv nu ämnar studera. Författarna önskar dig lycka till med kursen och hoppas att du kommer att få glädje av den. Speciellt hoppas vi att denna skrift ska underlätta för dig att tillgodogöra dig informationen vid föreläsningarna och under laborationerna.
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| 2. |
- Heijl, Anders, et al.
(författare)
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Nordic research in ophthalmology.
- 2005
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Ingår i: Acta ophthalmologica Scandinavica. - : Wiley. - 1395-3907 .- 1600-0420. ; 83:3, s. 278-88
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nordic ophthalmologists and vision scientists are active in many fields of eye research. This is most evident at the biannual Nordic Congress of Ophthalmology, most recently held in Malmö in June 2004. The authors here review some of the research in vision and ophthalmology presented at this meeting or published recently by Nordic scientists. This paper does not represent a comprehensive review of all Nordic research in the field, but attempts to give an overview of some of the activities underway in eye research in this part of the world.
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| 3. |
- Nordin Fredrikson, Gunilla, et al.
(författare)
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Association between IgM against an aldehyde-modified peptide in apo B-100 and progression of carotid disease.
- 2007
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Ingår i: Stroke. - : Lippincott Williams & Wilkins. - 0039-2499 .- 1524-4628. ; 38, s. 1495-1500
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose— Autoantibodies against antigens in oxidized low-density lipoprotein are common in people; experimental studies suggest that these immune responses have a functional role in the disease process. The aim of this study was to evaluate the relationship between the immune response against one defined oxidized low-density lipoprotein antigen, the aldehyde-modified peptide corresponding amino acids 3136 and 3155 (MDA-p210) in apolipoprotein (apo) B-100, and progression of carotid intima media thickness (IMT).Methods— IgM and IgG against MDA-p210 were determined by enzyme-linked immunosorbent assay at baseline and after 12 months of treatment with placebo, metoprolol, fluvastatin, or metoprolol/fluvastatin in 751 individuals participating in the BCAPS. Carotid IMT was assessed by ultrasonography at baseline and after 18 and 36 months of treatment.Results— Antibody levels did not change in response to treatment, but high baseline MDA-p210 IgM levels were associated with a more rapid progression of carotid disease both at 18 (r=0.09, P<0.05) and 36 months (r=0.12, P<0.005). At 36 months, the difference in IMT progression rate per year between those with high MDA-p210 IgM levels and those with low was 0.011 mm (95% CI=0.005 to 0.018 mm, P<0.0001). Treatment with fluvastatin markedly decreased the progression of IMT among subjects with high but not with low MDA-p210 IgM levels. There was no association between MDA-p210 IgG and carotid IMT progression.Conclusions— IgM against the aldehyde-modified peptide corresponding amino acids 3136 and 3155 in apo B-100 is common in subjects with asymptomatic carotid disease, and high levels are associated with a more rapid progression of carotid IMT. The observation that the effect of fluvastatin was restricted to subjects with high MDA-p210 IgM levels may reflect the increased rate of disease progression in this group.
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| 4. |
- Nordin Fredrikson, Gunilla, et al.
(författare)
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Association between IgM against an aldehyde-modified peptide in apolipoprotein B-100 and progression of carotid disease
- 2007
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Ingår i: Stroke: a journal of cerebral circulation. - 1524-4628. ; 38:5, s. 1495-1500
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose - Autoantibodies against antigens in oxidized low-density lipoprotein are common in people; experimental studies suggest that these immune responses have a functional role in the disease process. The aim of this study was to evaluate the relationship between the immune response against one defined oxidized low-density lipoprotein antigen, the aldehyde-modified peptide corresponding amino acids 3136 and 3155 (MDA-p210) in apolipoprotein (apo) B-100, and progression of carotid intima media thickness (IMT). Methods - IgM and IgG against MDA-p210 were determined by enzyme-linked immunosorbent assay at baseline and after 12 months of treatment with placebo, metoprolol, fluvastatin, or metoprolol/ fluvastatin in 751 individuals participating in the BCAPS. Carotid IMT was assessed by ultrasonography at baseline and after 18 and 36 months of treatment. Results - Antibody levels did not change in response to treatment, but high baseline MDA-p210 IgM levels were associated with a more rapid progression of carotid disease both at 18 ( r = 0.09, P < 0.05) and 36 months ( r = 0.12, P < 0.005). At 36 months, the difference in IMT progression rate per year between those with high MDA-p210 IgM levels and those with low was 0.011 mm ( 95% CI = 0.005 to 0.018 mm, P < 0.0001). Treatment with fluvastatin markedly decreased the progression of IMT among subjects with high but not with low MDA-p210 IgM levels. There was no association between MDA-p210 IgG and carotid IMT progression. Conclusions - IgM against the aldehyde-modified peptide corresponding amino acids 3136 and 3155 in apo B-100 is common in subjects with asymptomatic carotid disease, and high levels are associated with a more rapid progression of carotid IMT. The observation that the effect of fluvastatin was restricted to subjects with high MDA-p210 IgM levels may reflect the increased rate of disease progression in this group.
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| 5. |
- Nordin Fredrikson, Gunilla, et al.
(författare)
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Identification of autoantibodies in human plasma recognizing an apoB-100 LDL receptor binding site peptide
- 2006
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Ingår i: Journal of Lipid Research. - 1539-7262 .- 0022-2275. ; 47:9, s. 2049-2054
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to test the hypothesis that autoantibodies recognize amino acid sequences in the LDL receptor binding region of apolipoprotein B-100 (apoB-100). Autoantibodies against an unmodified or malondialdehyde (MDA)-modified LDL receptor binding site peptide were determined by ELISA in baseline plasma samples of 78 cases with coronary events and 149 matched controls recruited from the prospective Malmo Diet Cancer Study. IgG and IgM recognizing this peptide were detected in all subjects but did not differ between cases and controls. Inverse associations were observed between IgG against the native binding site and plasma oxidized LDL (r = -0.21, P < 0.005), but there were no significant associations with total or LDL cholesterol levels. In univariate analyses, inverse associations were found between baseline carotid intima-media thickness and IgG against the MDA-modified binding site (r = -0.14, P < 0.05), but this association was lost when controlling for other major cardiovascular risk factors. Specificity studies demonstrated that the binding of autoantibodies to these sequences could be inhibited by oxidized but not by native LDL. Autoantibodies recognizing the LDL receptor binding site in apoB-100 are frequently expressed. Their association with plasma oxidized LDL suggests that they have been generated in response to breakdown products of LDL oxidation, but their influence on cholesterol metabolism and the development of atherosclerosis appears limited.
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| 6. |
- Tjelmeland, Ingvild B.M., et al.
(författare)
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Description of Emergency Medical Services, treatment of cardiac arrest patients and cardiac arrest registries in Europe
- 2020
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Ingår i: Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. - : Springer Science and Business Media LLC. - 1757-7241. ; 28:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Variation in the incidence, survival rate and factors associated with survival after cardiac arrest in Europe is reported. Some studies have tried to fill the knowledge gap regarding the epidemiology of out-of-hospital cardiac arrest in Europe but were unable to identify reasons for the reported differences. Therefore, the purpose of this study was to describe European Emergency Medical Systems, particularly from the perspective of country and ambulance service characteristics, cardiac arrest identification, dispatch, treatment, and monitoring. Methods: An online questionnaire with 51 questions about ambulance and dispatch characteristics, on-scene management of cardiac arrest and the availability and dataset in cardiac arrest registries, was sent to all national coordinators who participated in the European Registry of Cardiac Arrest studies. In addition, individual invitations were sent to the remaining European countries. Results: Participants from 28 European countries responded to the questionnaire. Results were combined with official information on population density. Overall, the number of Emergency Medical Service missions, level of training of personnel, availability of Helicopter Emergency Medical Services and the involvement of first responders varied across and within countries. There were similarities in team training, availability of key resuscitation equipment and permission for ongoing performance of cardiopulmonary resuscitation during transported. The quality of reporting to cardiac arrest registries varied, as well as the data availability in the registries. Conclusions: Throughout Europe there are important differences in Emergency Medical Service systems and the response to out-of-hospital cardiac arrest. Explaining these differences is complicated due to significant variation in how variables are reported to and used in registries.
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| 7. |
- Aczel, Balazs, et al.
(författare)
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Consensus-based guidance for conducting and reporting multi-analyst studies
- 2021
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Ingår i: eLIFE. - : eLife Sciences Publications. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Any large dataset can be analyzed in a number of ways, and it is possible that the use of different analysis strategies will lead to different results and conclusions. One way to assess whether the results obtained depend on the analysis strategy chosen is to employ multiple analysts and leave each of them free to follow their own approach. Here, we present consensus-based guidance for conducting and reporting such multi-analyst studies, and we discuss how broader adoption of the multi-analyst approach has the potential to strengthen the robustness of results and conclusions obtained from analyses of datasets in basic and applied research.
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| 8. |
- Adolfsson, Emelie, 1985-, et al.
(författare)
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Response of Lithium Formate EPR Dosimeters at Photon Energies Relelvant to Brachytherapy
- 2009
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Ingår i: IFMBE Proceedings. - Heidelberg : Springer Berlin Heidelberg. - 9783642034725 - 9783642034749 ; , s. 236-239
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- After development of sensitive dosimeter materials Electron Paramagnetic Resonance EPR dosimetry has been successfully used also in radiation therapy. The intensity of the EPR-signal is a measure of the amount of free radicals created by ionizing radiation which is proportional to the absorbed dose in the dosimeter. Lithium formate monohydrate is a dosimeter material with 2-6 times higher sensitivity than alanine, a linear dose response over a wide dose range and mass-energy absorption properties similar to water. These properties make lithium formate promising for verification of absorbed doses around high dose rate brachytherapy sources where the dose gradient is steep and the photon energy distribution changing with distance from the source. Calibration of the dosimeters is performed in 60Co or MV photon beams where high dosimetric accuracy is feasible. The use in brachytherapy field relies on the assumption that the production of free radicals per mean absorbed dose in the dosimeter is similar at the lower photon energies present there. The aim of this work was to test that assumption. The response of the dosimeters as a function of photon energy was determined by irradiations with four x-ray qualities in the range 100-250 kV and 137Cs, relative to the response when irradiated with 60Co, all photon beams with well-known air kerma rates at the Swedish Secondary Standards Dosimetry Laboratory. Monte Carlo simulations were used to convert air kerma free in air to mean absorbed dose to the dosimeter. The measured response relative 60Co as a function of photon energy was below unity for all qualities. The maximum deviation from unity was 2.5% (100 kV, 135 kV) with a relative standard deviation of 1.5% (k = 1).
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| 9. |
- Adolfsson, Emelie, et al.
(författare)
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Response of lithium formate EPR dosimeters at photon energies relevant to the dosimetry of brachytherapy
- 2010
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Ingår i: Medical physics (Lancaster). - : American Association of Physicists in Medicine. - 0094-2405. ; 37:9, s. 4946-4959
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:To investigate experimentally the energy dependence of the detector response of lithium formate EPR dosimeters for photon energies below 1 MeV relative to that at 60Co energies. High energy photon beams are used in calibrating dosimeters for use in brachytherapy since the absorbed dose to water can be determined with high accuracy in such beams using calibrated ion chambers and standard dosimetry protocols. In addition to any differences in mass-energy absorption properties between water and detector, variations in radiation yield (detector response) with radiation quality, caused by differences in the density of ionization in the energy imparted (LET), may exist. Knowledge of an eventual deviation in detector response with photon energy is important for attaining high accuracy in measured brachytherapy dose distributions.METHODS:Lithium formate EPR dosimeters were irradiated to known levels of air kerma in 25-250 kV x-ray beams and in 137Cs and 60Co beams at the Swedish Secondary Standards Dosimetry Laboratory. Conversions from air kerma free in air into values of mean absorbed dose to the detectors were made using EGSnrc MC simulations and x-ray energy spectra measured or calculated for the actual beams. The signals from the detectors were measured using EPR spectrometry. Detector response (the EPR signal per mean absorbed dose to the detector) relative to that for 60Co was determined for each beam quality.RESULTS:Significant decreases in the relative response ranging from 5% to 6% were seen for x-ray beams at tube voltages < or = 180 kV. No significant reduction in the relative response was seen for 137Cs and 250 kV x rays.CONCLUSIONS:When calibrated in 60Co or MV photon beams, corrections for the photon energy dependence of detector response are needed to achieve the highest accuracy when using lithium formate EPR dosimeters for measuring absorbed doses around brachytherapy sources emitting photons in the energy range of 20-150 keV such as 169Yb and electronic sources.
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| 10. |
- Alm Fjellborg, Andreas, 1982-
(författare)
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Housing tenure and residential mobility in Stockholm 1990-2014
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis the links between housing tenure, income and selective, segregation generating, residential mobility are explored. The development of these links is analysed against the background of housing regime changes in Stockholm between 1990 and 2014. Housing policy changes in Sweden, and Stockholm, promote ownership through, for instance, housing tenure conversions and the tax-system. What this development means for residential mobility trends and may mean for ethnic and economic segregation is explored in three articles. Paper 1 contrasts two time periods and provides an analysis of residential mobility and economic sorting. It is shown that the socioeconomic composition of movers is relatively stable over time while the increasingly owner dominated housing market in Stockholm contributes to stronger socio-spatial residential patterns through the strengthened economic sorting of movers across the whole income scale. Paper 2 has a focus on ethnic and socioeconomic differences in out-mobility from poor neighbourhoods. The findings indicate that foreign background residents are dependent upon housing wealth and income to be able to leave poor neighbourhoods when they move, while the Swedish background group has a variety of resources at their disposal when they move. Paper 3 analyses how housing tenure affects moving, and movers' destinations, in neighbourhoods with high concentrations of non-western foreign-born residents in Stockholm. By comparing two cohorts (1993-2000 and 2001-2008) it is analysed how this relationship develops over time. Housing tenure and income do not seem to be pivotal for who moves, but increasingly important for where movers end up. Results display ethnic differences and how the changing housing market in Stockholm reproduces ethnic segregation. Two main conclusions from the thesis are that (i) the changing housing regime in Stockholm produces stronger economic sorting of movers – this has been affected by the geographically, socioeconomically and ethnically uneven gains from the housing market transformations experienced over the last three decades. (ii) The residential mobility patterns and the economic stratification of residential mobility opportunities that the reconfiguration of Stockholm’s housing market gives rise to increases the economic, political and social marginalization of neighbourhoods characterized by low income levels and high shares of foreign-born residents. Combating ethnic segregation is today even more closely related to the socioeconomic differences between the foreign-born and native-born parts of the population.
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