| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Potapkin, V., et al.
(författare)
-
Magnetic interactions in NiO at ultrahigh pressure
- 2016
-
Ingår i: PHYSICAL REVIEW B. - : AMER PHYSICAL SOC. - 2469-9950. ; 93:20, s. 201110-
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic properties of NiO have been studied in the multimegabar pressure range by nuclear forward scattering of synchrotron radiation using the 67.4 keV Mossbauer transition of Ni-61. The observed magnetic hyperfine splitting confirms the antiferromagnetic state of NiO up to 280 GPa, the highest pressure where magnetism has been observed so far, in any material. Remarkably, the hyperfine field increases from 8.47 T at ambient pressure to similar to 24 T at the highest pressure, ruling out the possibility of a magnetic collapse. A joint x-ray diffraction and extended x-ray-absorption fine structure investigation reveals that NiO remains in a distorted sodium chloride structure in the entire studied pressure range. Ab initio calculations support the experimental observations, and further indicate a complete absence of Mott transition in NiO up to at least 280 GPa.
|
|
| 5. |
- Ruban, Andrei V., et al.
(författare)
-
Origin of magnetic frustrations in Fe-Ni Invar alloys
- 2005
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 71:5, s. 4402-
-
Tidskriftsartikel (refereegranskat)abstract
- Pair exchange parameters J(ij) of the classical Heisenberg Hamiltonian for magnetic interactions in the archetypical Invar system, face centered cubic (fcc) Fe-Ni alloys, are calculated from the first principles. The magnetic structure of Fe-Ni alloys in the region of volumes and electron concentrations related to the Invar effect is highly frustrated. However, the origin of such a frustration in concentrated alloys and in the pure fcc Fe are different. While in Fe it is due to the long-range oscillating J(ij), in alloys with high Ni concentration it is mainly the consequence of a huge dispersion of the nearest-neighbor exchange parameters, caused by the local environment effects.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Belonoshko, Anatoly, et al.
(författare)
-
Elastic properties of body-centered cubic iron in Earth's inner core
- 2022
-
Ingår i: Physical Review B. - : American Physical Society (APS). - 2469-9950 .- 2469-9969. ; 105:18
-
Tidskriftsartikel (refereegranskat)abstract
- The solid Earth's inner core (IC) is a sphere with a radius of about 1300 km in the center of the Earth. The information about the IC comes mainly from seismic studies. The composition of the IC is obtained by matching the seismic data and properties of candidate phases subjected to high pressure (P) and temperature (T). The close match between the density of the IC and iron suggests that the main constituent of the IC is iron. However, the stable phase of iron is still a subject of debate. One such iron phase, the body-centered cubic phase (bcc), is dynamically unstable at pressures of the IC (330-364 GPa) and low T but gets stabilized at high T characteristic of the IC (5000-7000 K). So far, ab initio molecular dynamics (AIMD) studies attempted to compute the bcc elastic properties for a small (order of 102) number of atoms. The mechanism of the bcc stabilization cannot be enabled in such cells and that has led to erroneous results. Here we apply AIMD to compute elastic moduli and sound velocities of the Fe bcc phase for a 2000 Fe atom computational cell, which is a cell of unprecedented size for ab initio calculations of iron. Unlike in previous ab initio calculations, both the longitudinal and the shear sound velocities of the Fe bcc phase closely match the properties of the IC material at P = 360 GPa and T = 6600 K, likely the PT conditions in the IC. The calculated density of the bcc iron at these PT conditions is just 3% higher than the density of the IC material according to the Preliminary Earth Model. This suggests that the widely assumed amount of light elements in the IC may need a reconsideration. The anisotropy of the bcc phase is an exact match to the most recent seismic studies.
|
|
| 9. |
- Comasco, Erika, et al.
(författare)
-
Adipocytokines levels at delivery, functional variation of TFAP2 beta, and maternal and neonatal anthropometric parameters
- 2013
-
Ingår i: Obesity. - : Wiley. - 1930-7381 .- 1930-739X. ; 21:10, s. 2130-2137
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVEAdipocytokines participate in the regulation of glucose metabolism and foetal development. The transcription factor activating protein 2B (TFAP2β) has been associated with adipocytokine regulation, and gene variations with type 2 diabetes and obesity. This study investigated associations between maternal TFAP2B variation, adipocytokines levels and maternal and neonatal anthropometric characteristics.DESIGN AND METHODSA population-based sample of women was followed from delivery to six months postpartum. Adiponectin, leptin and interleukin-6 levels at delivery, and maternal as well as neonatal anthropometric variables were assessed. The TFAP2β intron 1 variable number tandem repeat (VNTR) was genotyped.RESULTSMaternal interleukin-6 correlated positively with leptin at delivery, with peripartum weight changes and weight of newborn males, adjusted for potential confounders. Leptin at delivery was associated with TFAP2β intron 1 VNTR genotype, adjusted for confounders, maternal weight and negatively with birth weight among female neonates. A path model suggested a link between TFAP2β genotype, leptin levels and newborn females' weight.CONCLUSIONSThe present results stress a role for the TFAP2 β in adiposity-related conditions and intrauterine growth. The association between neonatal birth weight and maternal adipocytokine levels, together with the observed sex effect, call for further studies on the mechanisms behind neuro-endocrine foetal programming.
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Hermansson, Kersti, et al.
(författare)
-
Hydrogen bond studies. CXX. An X-ray determination of the crystal structure of LiNO 3.3H 2O
- 1977
-
Ingår i: Acta Crystallogr. B, Struct. Crystallogr. Cryst. Chem. (Denmark). - 0567-7408. ; B33, s. 2857-2861
-
Tidskriftsartikel (refereegranskat)abstract
- For pt.CXIX see Z. Naturforsch. a, vol.32, p.134 (1977). The crystal structure of lithium nitrate trihydrate, LiNO 3.3H 2O, has been determined by X-ray diffraction at 295K. The crystal is orthorhombic, space group Cmcm, a=6.8018 (4), b=12.7132 (9), c=5.9990 (4) Aring, V=518.75 Aring 3, Z=4. The nitrate ions, Li + ions and one of the two crystallographically non-equivalent water molecules lie in a mirror plane and are bonded to atoms in adjacent planes through the second water molecule. The Li + ion is octahedrally surrounded by six O atoms, four belonging to water molecules and two to nitrate ions. The two non-equivalent water molecules are present in the structure in distinctly different bonding situations. One is bonded to two Li + ions and is the donor of two hydrogen bonds. The other is involved in six hydrogen bonds: the O atom accepts two hydrogen bonds, and both protons are involved in bifurcated hydrogen bonds.
|
|
| 14. |
- Hermansson, K., et al.
(författare)
-
Hydrogen bond studies. CXXXVIII. Neutron diffraction studies of LiNO 3.3H 2O at 120 and 295K
- 1980
-
Ingår i: Acta Crystallogr. B, Struct. Crystallogr. Cryst. Chem. (Denmark). - 0567-7408. ; B36, s. 1032-1040
-
Tidskriftsartikel (refereegranskat)abstract
- For pt.CXXXVII see ibid., vol.B35, p.2384 (1979). LiNO 3.3H 2O has been studied by neutron diffraction at 120 and 295 K. The final R(w.F 2) values are 4.5% (120K) and 4.9% (295K). The crystal structure found in a previous room-temperature X-ray study is confirmed: one water molecule is involved in six hydrogen bonds; the other independent water molecule in the structure has a tetrahedral environment comprising two Li + ions and two medium-strong hydrogen bonds. The four different O...O hydrogen-bond lengths increase by 0.02-0.03 Aring going from 120 to 295K. The mean-square amplitudes of vibration for the N and O atoms are found to be closely proportional to temperature. For the H and Li atoms the vibrational amplitudes are less sensitive to temperature. Crystal data: space group Cmcm, Z=4; at 120K a=6.713 (7), b=12.669 (4), c=5.968 (5) Aring; at 295K a=6.8018 (4), b=12.7132 (9), c=5.9990 (4) Aring.
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
|
|
| 26. |
- Olovsson, Weine, et al.
(författare)
-
The Be K-edge in beryllium oxide and chalcogenides : soft x-ray absorption spectra from first-principles theory and experiment
- 2013
-
Ingår i: Journal of Physics. - : Institute of Physics: Hybrid Open Access. - 0953-8984 .- 1361-648X. ; 25:31
-
Tidskriftsartikel (refereegranskat)abstract
- We have carried out a theoretical and experimental investigation of the beryllium K-edge soft x-ray absorption fine structure of beryllium compounds in the oxygen group, considering BeO, BeS, BeSe, and BeTe. Theoretical spectra are obtained ab initio, through many-body perturbation theory, by solving the Bethe–Salpeter equation (BSE), and by supercell calculations using the core-hole approximation. All calculations are performed with the full-potential linearized augmented plane-wave method. It is found that the two different theoretical approaches produce a similar fine structure, in good agreement with the experimental data. Using the BSE results, we interpret the spectra, distinguishing between bound core-excitons and higher energy excitations.
|
|
| 27. |
|
|
| 28. |
- Skalkidou, A., et al.
(författare)
-
Risk of Postpartum Depression in Association with Serum Leptin Levels: A Nested Case-control Study within the Uppsat Cohort.
- 2009
-
Ingår i: European psychiatry. - : Cambridge University Press (CUP). - 0924-9338 .- 1778-3585. ; 24:S1, s. 1-1
-
Tidskriftsartikel (refereegranskat)abstract
- Although postpartum depression (PPD) is a common condition, it often goes undiagnosed and untreated, with devastating consequences for the woman's ability to perform daily activities, to bond with her infant and to relate to the infant's father. Leptin, a protein synthesised in the adipose tissue and involved in regulation of food intake and energy expenditure has been related to depressive disorders, but studies report conflicting results. The aim of this study was to evaluate the association between serum leptin levels at the time of delivery and the subsequent development of postpartum depression in women, using data from a population-based cohort of delivering women in Uppsala, Sweden. Three hundred and sixty five women from which serum was obtained at the time of delivery filled out at least one of three pre-coded questionnaires containing the Edinbourgh Scale for Postnatal Depression (EPDS) five days, six weeks and six months after delivery. Crude mean leptin levels did not significantly differ between cases of PPD and controls. Using linear regression analysis and adjusting for maternal age, body-mass index, smoking, interleukin-6 levels, duration of gestation, gender and birth weight of the newborn, the EPDS scores at five days, six weeks and six months after delivery were negatively correlated with leptin levels at delivery (p< 0.05). Serum leptin levels at delivery were found to be negatively correlated with self reported depression during the first six months after delivery.
|
|
| 29. |
|
|
| 30. |
|
|
| 31. |
|
|
