| 1. |
- Bidlingmaier, Martin, et al.
(författare)
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Reference Intervals for Insulin-like Growth Factor-1 (IGF-1) From Birth to Senescence: Results From a Multicenter Study Using a New Automated Chemiluminescence IGF-1 Immunoassay Conforming to Recent International Recommendations.
- 2014
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 99:5
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Tidskriftsartikel (refereegranskat)abstract
- Context: Measurement of IGF-1 is a cornerstone in diagnosis and monitoring of GH-related diseases, but considerable discrepancies exist between analytical methods. A recent consensus conference defined criteria for validation of IGF-1 assays and for establishment of normative data. Objectives: Our objectives were development and validation of a novel automated IGF-1 immunoassay (iSYS; Immunodiagnostic Systems) according to international guidelines and establishment of method-specific age- and sex-adjusted reference intervals and analysis of their robustness. Setting and Participants: We conducted a multicenter study with samples from 12 cohorts from the United States, Canada, and Europe including 15ü014 subjects (6697 males and 8317 females, 0-94 years of age). Main Outcome Measures: We measured concentrations of IGF-1 as determined by the IDS iSYS IGF-1 assay. Results: A new IGF-1 assay calibrated against the recommended standard (02/254) and insensitive to the 6 high-affinity IGF binding proteins was developed and rigorously validated. Age- and sex-adjusted reference intervals derived from a uniquely large cohort reflect the age-related pattern of IGF-1 secretion: a decline immediately after birth followed by an increase until a pubertal peak (at 15 years of age). Later in life, values decrease continuously. The impact of gender is small, although across the lifespan, women have lower mean IGF-1 concentrations. Geographical region, sampling setting (community or hospital based), and rigor of exclusion criteria in our large cohort did not affect the reference intervals. Conclusions: Using large cohorts of well-characterized subjects from different centers allowed construction of robust reference ranges for a new automated IGF-1 assay. The strict adherence to recent consensus criteria for IGF-1 assays might facilitate clinical application of the results.
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| 2. |
- Friedrich, Nele, et al.
(författare)
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Age and sex specific reference intervals across life-span for insulin-like growth factor binding protein 3 (IGFBP-3) and the IGF-I/IGFBP-3 ratio measured by new automated chemiluminescence assays.
- 2014
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Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 99:5
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Tidskriftsartikel (refereegranskat)abstract
- Context: Measurement of IGFBP-3 can aid the diagnosis of growth hormone related diseases. Furthermore, epidemiological studies suggest that IGFBP-3 and the molar IGF-I/IGFBP-3 ratio are associated with clinical endpoints like cancer or cardiovascular disease. However, their clinical use is limited by the lack of validated reference intervals. Objectives: Establishment of age- and sex-specific reference intervals for IGFBP-3 and the molar IGF-I/IGFBP-3 ratio by newly developed automated immunoassays. Setting: Multicentre study with samples from 11 cohorts from the USA, Canada and Europe Participants: 14,970 subjects healthy subjects covering all ages from birth to senescence. Main outcome measures: Concentrations of IGFBP-3 and the IGF-I/IGFBP-3 ratio as determined by the IDS iSYS IGF-I and IGFBP-3 assays. Results: Both the concentration of IGFBP-3 and the IGF-I/IGFBP-3 ratio are mainly determined by age. IGFBP-3 concentrations increase until the age of 22 years, with a plateau being visible between 15 and 25 years. Determined by the high peripubertal peak in IGF-I, the peak in the IGF-I/IGFBP-3 ratio occurs already around the age of 15, with a slightly earlier and higher peak in females. Beyond the age of 60, IGFBP-3 concentrations remain higher in females, whereas IGF-I as well as the IGF-I/IGFBP-3 ratio remain significantly higher in males. Conclusions: We present an extensive set of assay specific, age and sex-adjusted normative data for concentrations of IGFBP-3 and the molar IGF-I/IGFBP-3 ratio and demonstrate distinct sex specific differences across lifespan.
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| 3. |
- Mbabazi, Penelope B.
(författare)
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Quality in Learning in Rwandan Higher Education : Different stakeholders’ perceptions of students’ learning and employability
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the thesis is to investigate quality in learning in higher education in Rwanda by focusing on students’ learning and their employability. This focus allows for an understanding of key challenges for Rwandan higher education to emerge, at a time when more and more students are enrolling. Higher education is being rebuilt after the genocide of 1994 in Rwanda and the focus on quality in learning and preparing students for work life is thus timely and important. The empirical material comprises interviews with students, teachers and employers. Interpretation of this material is guided by perspectives on quality in learning: students’ approaches to learning, learning as transformation and employability. A meta-ethnographic analysis of the four articles on which the thesis is based generated five themes as central quality aspects of learning that could enhance the employability of graduates: becoming professional, skillful practices, becoming a learner, becoming responsible and international experience. The results illustrate that students have to some extent different views from employers and teachers regarding questions about quality in learning. Thus, it could be of value for policy makers and teachers to listen to what the students have to say when designing policy and curriculum in higher education in Rwanda.
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| 4. |
- Trummer, Martin, et al.
(författare)
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The effect of Y2O3 on the dynamics of oxidative dissolution of UO2
- 2010
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Ingår i: Journal of Nuclear Materials. - : Elsevier. - 0022-3115 .- 1873-4820. ; 407:3, s. 195-199
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we have studied the impact of Y2O3 on the kinetics of oxidative dissolution of UO2 and the consumption of H2O2. The second order kinetics of catalytic consumption of H2O2 on Y2O3 was investigated in aqueous Y2O3 powder suspensions by varying the solid surface area to solution volume ratio. The resulting second order rate constant is 10(-8) m s(-1), which is of the same magnitude as for the reaction between H2O2 and UO2. Powder experiments with mixtures of UO2 and Y2O3 show that Y2O3 has no effect on the oxidative dissolution of UO2, whereas the consumption of H2O2 seems to be slightly slower in the presence of Y2O3 and H-2 respectively. UO2 pellets with solid inclusions of Y2O3 show a decrease in oxidative dissolution by a factor of 3.3 and 5.3 under inert and hydrogen atmosphere, respectively. The rate of H2O2 consumption is similar for all cases and is well in line with kinetic data from powder experiments. The effects of H-2 and Y2O3 on the oxidative dissolution of UO2 under gamma irradiation are similar to those found in experiments with H2O2. No significant difference in dissolution between inert and reducing atmosphere can be observed for pure UO2.
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