| 41. |
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| 42. |
- Alwis, Gayani, et al.
(författare)
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Femoral Neck Bone Strength Estimated by Hip Structural Analysis (HSA) in Swedish Caucasians Aged 6-90 Years.
- 2012
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 90:3, s. 174-185
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Tidskriftsartikel (refereegranskat)abstract
- Dual-energy X-ray absorptiometry hip scans of 1,760 population-based Caucasians, 599 girls and 642 boys aged 6-19 years and 270 women and 249 men aged 20-90 years, were analyzed with the hip structural analysis (HSA) software to present age- and sex-specific normative HSA data of the femoral neck (FN). Measured traits included bone mineral density (BMD), cross-sectional area (CSA), section modulus (Z), periosteal diameter (PD), endosteal diameter (ED), cortical thickness (CT), and cross-sectional moment of inertia (CSMI). When plotting the measured traits versus age, the curves increased with higher ages until statistically significant break points were reached, for all traits at age 17 in girls and age 19 in boys. After the break points, PD and ED increased with higher ages but, as ED increased more than PD, BMD and CT decreased significantly with higher ages. The decline in BMD was counteracted by the increase in bone size so that there was only a nonstatistically significant decrease in bone strength, estimated as Z and CSMI, from break point to age 90. The partial preservation of bone strength was more obvious in men than in women as the decline in BMD was higher in women than in men, while the expansion in PD was larger in men than in women. The sex difference in the normative FN bone strength data seems to be related to sex discrepancies in the development of both bone mass and geometrical parameters during both growth and adulthood.
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| 43. |
- Alwis, Gayani, et al.
(författare)
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Normative Calcaneal Quantitative Ultrasound Data as an Estimation of Skeletal Development in Swedish Children and Adolescents.
- 2010
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 1432-0827 .- 0171-967X. ; 87, s. 493-506
-
Tidskriftsartikel (refereegranskat)abstract
- We present age- and gender-specific normative bone status data evaluated by quantitative ultrasound (QUS) in the calcaneus with the Lunar Achilles device and compare these estimates with bone mineral content (BMC) and bone mineral density (BMD) estimated by dual X-ray absorptiometry (DXA). Included were a sample of 518 population-based collected Swedish girls and 558 boys aged 6-19 years. QUS measurements included speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI) in the calcaneus. DXA measurements included BMC and BMD in the femoral neck (FN), lumbar spine (L2-L4), and total body (TB). Height and weight were measured with standard equipment. Age, height, and weight were significantly associated with SOS, BUA, and SI. Compared to SOS, in both girls and boys there was a higher correlation between BUA and FN BMC (r = 0.71 and r = 0.73, respectively), FN BMD (r = 0.68 and r = 0.67, respectively), L2-L4 BMC (r = 0.70 and r = 0.64, respectively), L2-L4 BMD (r = 0.69 and r = 0.64, respectively), TB BMC (r = 0.76 and r = 0.75, respectively), and TB BMD (r = 0.74 and r = 0.74, respectively). The correlations between SOS and FN BMC (r = 0.38 and r = 0.52, respectively), FN BMD (r = 0.41 and r = 0.52, respectively), L2-L4 BMC (r = 0.31 and r = 0.40, respectively), L2-L4 BMD (r = 0.32 and r = 0.41, respectively), TB BMC (r = 0.42 and r = 0.49, respectively), and TB BMD (r = 0.48 and r = 0.54, respectively) were lower, although still significant (all P < 0.001). BUA seems to be the QUS parameter that best resembles the changes in BMC during growth.
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| 44. |
- Alwis, Gayani, et al.
(författare)
-
Normative dual energy X-ray absorptiometry data in Swedish children and adolescents.
- 2010
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Ingår i: Acta paediatrica. - : Wiley. - 1651-2227 .- 0803-5253. ; 99, s. 1091-1099
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To present normative dual energy X-ray absorptiometry data in healthy young Swedes. Methods: Included were 710 girls and 759 boys aged 6-30 years from southern Sweden. Bone mineral content, bone mineral density, bone size, lean body and fat mass were measured by dual energy X-ray absorptiometry in total body, lumbar spine, hip, arms and legs. Results: Swedish children had similar bone mass to children in the Netherlands but higher than children in Canada and Korea. Height, weight, bone mass, bone size and lean mass increased at a constant rate from age 6 until the rapid increase in all traits at puberty. The pubertal growth spurt started earlier in girls than in boys, while the spurt in boys was larger in magnitude and occurred for a longer period. Around one-quarter of the adult total body and lumbar spine peak bone mineral content was gained during the 2 years with the fastest gain in both genders. Conclusion: This study presents normative bone mass data in Swedish children, data that are similar to that in Dutch children but higher than in Canadian and Korean children. The gain in Swedish children seems to mimic the gain seen in children in other settings.
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| 45. |
- Amkreutz, J. A. M. P., et al.
(författare)
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Association Between Bone Mineral Density and Autoantibodies in Patients With Rheumatoid Arthritis
- 2021
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Ingår i: Arthritis and Rheumatology. - : Wiley. - 2326-5191 .- 2326-5205. ; 73:6, s. 921-930
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Autoantibodies, such as anti–citrullinated protein antibodies (ACPAs), have been described as inducing bone loss in rheumatoid arthritis (RA), which can also be reflected by bone mineral density (BMD). We therefore examined the association between osteoporosis and autoantibodies in two independent RA cohorts. Methods: Dual x-ray absorptiometry (DXA) of the lumbar spine and left hip was performed in 408 Dutch patients with early RA during 5 years of follow-up and in 198 Swedish patients with early RA during 10 years of follow-up. The longitudinal effect of ACPAs and other autoantibodies on several BMD measures was assessed using generalized estimating equations. Results: In the Dutch cohort, significantly lower BMD at baseline was observed in ACPA-positive patients compared to ACPA-negative patients, with an estimated marginal mean BMD in the left hip of 0.92 g/cm2 (95% confidence interval [95% CI] 0.91–0.93) versus 0.95 g/cm2 (95% CI 0.93–0.97) (P = 0.01). In line with this, significantly lower Z scores at baseline were noted in the ACPA-positive group compared to the ACPA-negative group (estimated marginal mean Z score in the left hip of 0.18 [95% CI 0.08–0.29] versus 0.48 [95% CI 0.33–0.63]) (P < 0.01). However, despite clear differences at baseline, ACPA positivity was not associated with greater decrease in absolute BMD or Z scores over time. Furthermore, there was no association between BMD and higher levels of ACPAs or other autoantibodies (rheumatoid factor and anti–carbamylated protein antibodies). In the Swedish cohort, ACPA-positive patients tended to have a higher prevalence of osteopenia at baseline (P = 0.04), but again, ACPA positivity was not associated with an increased prevalence of osteopenia or osteoporosis over time. Conclusion: The presence of ACPAs is associated with significantly lower BMD at baseline, but not with greater BMD loss over time in treated RA patients. These results suggest that ACPAs alone do not appear to contribute to bone loss after disease onset when disease activity is well-managed. © 2020 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.
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| 46. |
- Ammenberg, Jonas, et al.
(författare)
-
Biogas Research Center, BRC : Slutrapport för etapp 1
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Biogas Research Center (BRC) är ett kompetenscentrum för biogasforskning som finansieras av Energimyndigheten, LiU och ett flertal externa organisationer med en tredjedel vardera. BRC har en mycket bred tvärvetenskaplig inriktning och sammanför biogasrelaterad kompetens från flera olika områden för att skapa interaktion på flera olika plan:mellan näringsliv, akademi och samhälle,mellan olika perspektiv, samtmellan olika discipliner och kompetensområden.BRC:s vision är:Resurseffektiva biogaslösningar finns genomförda i många nya tillämpningar och bidrar till en mer hållbar energiförsörjning, förbättrat miljötillstånd och goda affärer.BRC:s särskilda roll för att uppnå denna vision är att bidra med kunskapsförsörjning och process-/teknikutveckling för att facilitera utveckling, innovation och implementering av biogaslösningar. Resurseffektivitet är ett nyckelord, vilket handlar om att förbättra befintliga processer och system samt utveckla biogaslösningar i nya sektorer och möjliggöra användning av nya substrat.For BRC:s etapp 1, den första tvåårsperioden mellan 2012-2014, var forskningsprojekten organiserade enligt tabellen nedan. Den visar viktiga utmaningar för biogasproducenter och andra intressenter, samt hur dessa ”angreps” med åtta forskningsprojekt. Fem av projekten var av explorativ karaktär i bemärkelsen att de var bredare och mer framtidsorienterade - exempelvis utvärderade flera möjliga tekniska utvecklingsmöjligheter (EP1-5). Tre projekt hade ett tydligare fokus på teknik- och processutveckling (DP6-8).I den här slutrapporten ges en kortfattad bakgrundsbeskrivning och det finns en introduktion till vad den här typen av kompetenscentrum innebär generellt. Därefter finns mer detaljerad information om BRC, exempelvis gäller det centrumets etablering, relevans, vision, hörnstenar och utveckling. De deltagande organisationerna presenteras, både forskargrupperna vid Linköpings universitet och partners och medlemmar. Vidare finns en mer utförlig introduktion till och beskrivning av utmaningarna i tabellen och kortfattat information om forskningsprojekten, följt av ett kapitel som berör måluppfyllelse och den externa utvärdering som gjorts av BRC:s verksamhet. Detaljerad, listad information finns till stor del i bilagorna.Kortfattat kan det konstateras att måluppfyllelsen överlag är god. Det är speciellt positivt att så många vetenskapliga artiklar publicerats (eller är på gång att publiceras) kopplat till forskningsprojekten och även i det vidare centrumperspektivet. Helt klart förekommer en omfattande verksamhet inom och kopplat till BRC. I etapp 2 är det viktigt att öka andelen mycket nöjda partner och medlemmar, där nu hälften är nöjda och hälften mycket nöjda. Det handlar framför allt om stärkt kommunikation, interaktion och projektledning. Under 2015 förväntas åtminstone två doktorsexamina, där avhandlingarna har stor koppling till forskningen inom etapp 1.I början på år 2014 skedde en extern utvärdering av verksamheten vid BRC med huvudsyftet att bedöma hur väl centrumet lyckats med etableringen samt att granska om det fanns förutsättningar för framtida framgångsrik verksamhet. Generellt var utfallet mycket positivt och utvärderarna konstaterade att BRC på kort tid lyckats etablera en verksamhet som fungerar väl och engagerar det stora flertalet deltagande aktörer, inom relevanta områden och där de flesta involverade ser BRC som en befogad och väl fungerande satsning, som de har för avsikt att även fortsättningsvis stödja. Utvärderingen bidrog också med flera relevant tips och till att belysa utmaningar.Utöver denna slutrapport finns separata publikationer från forskningsprojekten.Arbetet som presenteras i rapporten har finansierats av Energimyndigheten och de medverkande organisationerna.
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| 47. |
- Anders, Berntson, et al.
(författare)
-
Self-phase modulation in dispersion compensated optical fibre transmission systems
- 1996
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Ingår i: Optics Communications. - : Elsevier. - 0030-4018 .- 1873-0310. ; 130:1-3, s. 153-162
-
Tidskriftsartikel (refereegranskat)abstract
- An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.
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| 48. |
- Anders, Berntson, et al.
(författare)
-
Self-phase modulation in dispersion compensated optical fibre transmission systems
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.
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| 49. |
- Anders, Berntson, et al.
(författare)
-
Self-phase modulation in dispersion-compensating systems
- 1996
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Ingår i: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS. - : IEEE. ; , s. 405-406
-
Konferensbidrag (refereegranskat)abstract
- The effects of SPM in a dispersion-compensation system are investigated. An explicit and compact formula is presented for the optimal length of the DCF. In particular, it is shown that the order of the fibers is important when SPM is considered. Using precompensation SPM effects can improve system performance. A qualitative comparison between the analytical predictions and previously presented experimental results show good agreement.
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| 50. |
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