| 1. |
- Dahlqvist, Martin, et al.
(author)
-
Complex magnetism in nanolaminated Mn2GaC
- 2014
-
Other publication (other academic/artistic)abstract
- We have used first-principles calculations and Heisenberg Monte Carlo simulations to search for the magnetic ground state of Mn2GaC, a recently synthesized magnetic nanolaminate. We have, independent on method, identified a range of low energy collinear as well as non-collinear magnetic configurations, indicating a highly frustrated magnetic material with several nearly degenerate magnetic states. An experimentally obtained magnetization of only 0.29 per Mn atom in Mn2GaC may be explained by canted spins in an antiferromagnetic configuration of ferromagnetically ordered sub-layers with alternating spin orientation, denoted AFM[0001]. Furthermore, low temperature X-ray diffraction show a new basal plane peak appearing upon a magnetic transition, which is consistent with the here predicted change in inter-layer spacing for the AFM[0001] configuration.
|
|
| 2. |
|
|
| 3. |
- Amer-Wåhlin, I, et al.
(author)
-
Swedish randomized controlled trial of cardiotocography only versus cardiotocography plus ST analysis of fetal electrocardiogram revisited : analysis of data according to standard versus modified intention-to-treat principle.
- 2011
-
In: Acta Obstetricia et Gynecologica Scandinavica. - : John Wiley & Sons Ltd.. - 0001-6349 .- 1600-0412. ; 90:9, s. 990-996
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: To undertake a renewed analysis of data from the previously published Swedish randomized controlled trial on intrapartum fetal monitoring with cardiotocography (CTG-only) vs. CTG plus ST analysis of fetal electrocardiogram (CTG+ST), using current standards of intention-to-treat (ITT) analysis and to compare the results with those of the modified ITT (mITT) and per protocol analyses. METHODS: Renewed extraction of data from the original database including all cases randomized according to primary case allocation (n=5 049). MAIN OUTCOME MEASURE: Metabolic acidosis in umbilical artery at birth (pH <7.05, base deficit in extracellular fluid >12.0 mmol/l) including samples of umbilical vein blood or neonatal blood if umbilical artery blood was missing. RESULTS: The metabolic acidosis rates were 0.66% (17 of 2 565) and 1.33% (33 of 2 484) in the CTG+ST and CTG-only groups, respectively [relative risk (RR) 0.50; 95% confidence interval (CI) 0.28-0.88; p=0.019]. The original mITT gave RR 0.47, 95%CI 0.25-0.86 (p=0.015), mITT with correction for 10 previously misclassified cases RR 0.48, 95%CI 0.24-0.96 (p=0.038) and per protocol analysis RR 0.40, 95%CI 0.20-0.80 (p=0.009). The level of significance of the difference in metabolic acidosis rates between the two groups remained unchanged in all analyses. CONCLUSION: Re-analysis of data according to the ITT principle showed that regardless of the method of analysis, the Swedish randomized controlled trial maintained its ability to demonstrate a significant reduction in metabolic acidosis rate when using CTG+ST analysis for fetal surveillance in labor.
|
|
| 4. |
|
|
| 5. |
- Cunningham, Laura, et al.
(author)
-
Climatic variability during the last interglacial inferred from geochemical proxies in the Lake El'gygytgyn sediment record
- 2013
-
In: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 386, s. 408-414
-
Journal article (peer-reviewed)abstract
- The Last Interglacial Period (LIP) is often regarded as a good analogue for potential climatic conditions under predicted global warming scenarios. Despite this, there is still debate over the nature, duration and frequency of climatic changes during this period. One particularly contentious issue has been the apparent evidence of climatic instability identified in many marine cores but seemingly lacking from many terrestrial archives, especially within the Arctic, a key region for global climate change research. In this paper, geochemical records from Lake El'gygytgyn, north-eastern Russia, are used to infer past climatic changes during the LIP from within the high Arctic. With a sampling resolution of similar to 20-similar to 90 years, these records offer the potential for detailed, high-resolution palaeoclimate reconstruction. This study shows that the LIP commenced in central Chukotka similar to 129 thousand years ago (ka), with the warmest climatic conditions occurring between similar to 128 and 127 ka before being interrupted by a short-lived cold reversal. Mild climatic conditions then persisted until similar to 122 ka when a marked reduction in the sedimentation rate suggests a decrease in precipitation. A further climatic deterioration at similar to 118 ka marks the return to glacial conditions. This study highlights the value of incorporating several geochemical proxies when inferring past climatic conditions, thus providing the potential to identify signals related to environmental change within the catchment. We also demonstrate the importance of considering how changes in sedimentation rate influence proxy records, in order to develop robust palaeoenvironmental reconstructions. (C) 2013 Elsevier B.V. All rights reserved.
|
|
| 6. |
- Daka, Bledar, 1976, et al.
(author)
-
Inverse association between serum insulin and sex hormone-binding globulin in a population survey in Sweden
- 2013
-
In: Endocrine Connections. - 2049-3614. ; 2:1, s. 18-22
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: Obesity is associated with low levels of sex hormone-binding globulin (SHBG). While the reason is not fully understood, we aimed to study the association between serum insulin and levels of SHBG in a random population. DESIGN AND METHODS: Between 2001 and 2005, a random sample of 2816 participants aged 30-74 years were enrolled in a cross-sectional survey in the South-west of Sweden. Fasting blood samples were collected and an oral glucose tolerance test (OGTT) was conducted in all subjects without known diabetes. Diabetes mellitus was defined according to criteria from WHO, and clinical characteristics were used to discriminate between type 1 (T1D) and type 2 diabetes (T2D). Analyses of SHBG were successful in 2782 participants (98%), who thus constituted the current study population. RESULTS: WE FOUND SIGNIFICANT INVERSE ASSOCIATION BETWEEN LEVELS OF SHBG AND FASTING SERUM INSULIN IN BOTH GENDERS (MEN: β=-0.090, P=0.001; women: β=-0.197, P<0.001), which was independent of differences in age and BMI. The associations remained when also differences in fasting plasma glucose were accounted for (men: β=-0.062, P=0.022; women: β=-0.176, P≤0.001). Subjects with T1D exhibited higher levels of SHBG than both T2D (men: δ=15.9nmol/l, P<0.001; women: δ=71.1nmol/l, P<0.001) and non-diabetic subjects (men: δ=15.1nmol/l, P<0.001; women: δ=72.9nmol/l, P<0.001) independent of age, BMI and fasting glucose levels. CONCLUSION: These findings are consistent with high levels of SHBG in T1D, and correspondingly low levels in T2D subjects, suggesting an inhibitory effect of insulin on the SHBG production in the liver.
|
|
| 7. |
- Daka, Bledar, et al.
(author)
-
Low sex hormone-binding globulin is associated with hypertension: a cross-sectional study in a Swedish population
- 2013
-
In: BMC Cardiovascular Disorders. - : Springer Science and Business Media LLC. - 1471-2261. ; 13
-
Journal article (peer-reviewed)abstract
- Background: The aim of this study was to investigate the association of sex hormone-binding globulin (SHBG) and hypertension in a Swedish population. Methods: The study is based on a random sample of a Swedish population of men and women aged 30-74 years (n=2,816). Total testosterone, oestradiol and SHBG were measured in 2,782 participants. Free androgen index was then calculated according to the formula FAI=100 x (Total testosterone)/SHBG. Hypertension was diagnosed according to JNC7. Results: In men, but not in women, significant association between SHBG and both diastolic (diastolic blood pressure: beta=-0.143 p<0.001) and systolic blood pressure (systolic blood pressure beta=-0.114 p<0.001) was found. The association was still significant after adjusting for age, body mass index (BMI), homeostatic model assessment insulin resistance (HOMA-IR), triglycerides, high density lipoproteins (HDL) and C-reactive protein (CRP) (diastolic blood pressure: beta=-0.113 p<0.001; systolic blood pressure beta=-0.093 p=0.001). An inverse association was observed between SHBG and hypertension in both men (B=-0.024 p<0.001) and women (B=-0.022 p<0.001). The association was still significant in women older than 50 years after adjustments for age, BMI, physical activity, CRP and alcohol consumption (B=-0.014, p=0.008). Conclusion: In conclusion, these results show a strong association between SHBG and blood pressure independent of major determinants of high blood pressure. This association might be addressed to direct effects of SHBG in endothelial cells through the receptor for SHBG. If this is confirmed by other observational and experimental studies, it might become a new field for the development of therapies for lowering blood pressure.
|
|
| 8. |
- Eklund, Per, et al.
(author)
-
Discovery of the Ternary Nanolaminated Compound Nb2GeC by a Systematic Theoretical-Experimental Approach
- 2012
-
In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 109:3, s. 035502-
-
Journal article (peer-reviewed)abstract
- Since the advent of theoretical materials science some 60 years ago, there has been a drive to predict and design new materials in silicio. Mathematical optimization procedures to determine phase stability can be generally applicable to complex ternary or higher-order materials systems where the phase diagrams of the binary constituents are sufficiently known. Here, we employ a simplex-optimization procedure to predict new compounds in the ternary Nb-Ge-C system. Our theoretical results show that the hypothetical Nb2GeC is stable, and excludes all reasonably conceivable competing hypothetical phases. We verify the existence of the Nb2GeC phase by thin film synthesis using magnetron sputtering. This hexagonal nanolaminated phase has a and c lattice parameters of similar to 3.24 angstrom and 12.82 angstrom.
|
|
| 9. |
- Eriksson, Anders, et al.
(author)
-
Nanocolumnar Epitaxial Ti1-xSixN (0 ≤ x ≤ 0.18) Thin Films Grown by Dual Reactive Magnetron Sputtering on MgO (001), (011), and (111) Substrates
- 2012
-
Other publication (other academic/artistic)abstract
- Ti1-xSixNy thin films and multilayers have been grown on single-crystal TiN-templated MgO (001), (011), and (111) substrates kept at 550 °C. Elemental Ti and Si targets were used in UVH reactive dual magnetron sputtering in a mixed Ar/N2 discharge. Composition analysis by time-of-flight energy elastic recoil detection analysis show that the films are close to stoichiometric (0.95 ≤ y ≤ 1.00) with respect to TiN over the wide range of Si concentrations 0 ≤ x ≤ 0.22. High-resolution transmission electron microscopy (TEM) combined with scanning TEM and energy dispersive Xray analysis show that all films grow epitaxially for x ≤ 0.18 and that as much as every fifth Ti atom can be replaced by Si (~10 at.%) in Ti1-xSixN(001). For the (011) and (111)-oriented films, however, only 1-2 at.% Si substitutes for Ti. Instead, Si segregates to form crystalline-to-amorphous SiNz (z ≈ 1) tissue phases, which promote the formation of epitaxial TiN nanocolumns. The nanocolumns have preferred {110} interfaces and {200} top facets and grow several hundreds of nm in length.
|
|
| 10. |
- Eriksson, Anders, et al.
(author)
-
Si incorporation in Ti1-xSixN films grown on TiN(001) and (001)-faceted TiN(111) columns
- 2014
-
In: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 257, s. 121-128
-
Journal article (peer-reviewed)abstract
- Thin films consisting of TiN nanocrystallites encapsulated in a fully percolated SiNy tissue phase are archetypes for hard and superhard nanocomposites. Here, we investigate metastable SiNy solid solubility in TiN and probe the effects of surface segregation during the growth of TiSiN films onto substrates that are either flat TiN(001)/MgO(001) epitaxial buffer layers or TiN(001) facets of length 1-5 nm terminating epitaxial TiN(111) nanocolumns, separated by voids, deposited on epitaxial TiN(111)/MgO(111) buffer layers. Using reactive magnetron sputter deposition, the TiSiN layers were grown at 550 degrees C and the TiN buffer layers at 900 degrees C On TiN(001), the films are NaCl-structure single-phase metastable Ti1-xSixN(001) with N/(Ti + Si) = 1 and 0 less than= x less than= 0.19. These alloys remain single-crystalline to critical thicknesses h(c) ranging from 100 +/- 30 nm with x = 0.13 to 40 +/- 10 nm with x = 0.19. At thicknesses h greater than h(c), the epitaxial growth front breaks down locally to form V-shaped polycrystalline columns with an underdense feather-like nanostructure. In contrast, the voided epitaxial TiN(111) columnar surfaces, as well as the TiN(001) facets, act as sinks for SiNy. For Ti1-xSixN layers with global average composition values less than x greater than = 0.16, the local x value in the middle of Ti1-xSixN columns increases from 0.08 for columns with radius r similar or equal to 2 nm to x = 0.14 with r similar or equal to 4 nm. The average out-of-plane lattice parameter of epitaxial nanocolumns encapsulated in SiNy decreases monotonically with increasing Si fraction less than x greater than, indicating the formation of metastable (Ti,Si)N solid solutions under growth conditions similar to those of superhard nanocomposites for which the faceted surfaces of nanograins also provide sinks for SiNy.
|
|
