| 11. |
- AHLBERG, PER, et al.
(författare)
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Integrated Cambrian biostratigraphy and carbon isotope chemostratigraphy of the Grönhögen-2015 drill core, Öland, Sweden
- 2019
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Ingår i: Geological Magazine. - 0016-7568. ; 156:06, s. 935-949
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Tidskriftsartikel (refereegranskat)abstract
- The Grönhögen-2015 core drilling on southern Öland, Sweden, penetrated 50.15 m of Cambrian Series 3, Furongian and Lower–Middle Ordovician strata. The Cambrian succession includes the Äleklinta Member (upper Stage 5) of the Borgholm Formation and the Alum Shale Formation (Guzhangian–Tremadocian). Agnostoids and trilobites allowed subdivision of the succession into eight biozones, in ascending order: the uppermost Cambrian Series 3 (Guzhangian) Agnostus pisiformis Zone and the Furongian Olenus gibbosus, O. truncatus, Parabolina spinulosa, Sphaerophthalmus? flagellifer, Ctenopyge tumida, C. linnarssoni and Parabolina lobata zones. Conspicuous lithologic unconformities and the biostratigraphy show that the succession is incomplete and that there are several substantial gaps of variable magnitudes. Carbon isotope analyses (δ13Corg) through the Alum Shale Formation revealed two globally significant excursions: the Steptoean Positive Carbon Isotope Excursion (SPICE) in the lower–middle Paibian Stage, and the negative Top of Cambrian Excursion (TOCE), previously referred to as the HERB Event, in Stage 10. The δ13Corg chemostratigraphy is tied directly to the biostratigraphy and used for an improved integration of these excursions with the standard agnostoid and trilobite zonation of Scandinavia. Their relations to that of coeval successions in Baltoscandia and elsewhere are discussed. The maximum amplitudes of the SPICE and TOCE in the Grönhögen succession are comparable to those recorded in drill cores retrieved from Scania, southern Sweden. The results of this study will be useful for assessing biostratigraphic relations between shale successions and carbonate facies on a global scale.
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| 12. |
- Ahlberg, Per, et al.
(författare)
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Miaolingian (Cambrian) trilobite biostratigraphy and carbon isotope chemostratigraphy in the Tingskullen drill core, Öland, Sweden
- 2021
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Ingår i: Estonian Journal of Earth Sciences. - : Estonian Academy Publishers. - 1736-7557 .- 1736-4728. ; 70:1, s. 18-35
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Tidskriftsartikel (refereegranskat)abstract
- The Cambrian succession of the Tingskullen drill core from northern Öland comprises Cambrian Series 2 and Miaolingian (Wuliuan Stage) siliciclastic strata. The major portion of the succession is represented by the Miaolingian Borgholm Formation, which, in ascending order, is subdivided into the Mossberga, Bårstad and Äleklinta members. The Äleklinta Member is barren of body fossils, whereas the Mossberga and Bårstad members are moderately to highly fossiliferous and biostratigraphically reasonably well constrained. Trilobites and agnostoids from the Bårstad Member are indicative of the Acadoparadoxides pinus Zone.The Mossberga Member has not yielded any zonal guide fossils but is tentatively assigned to the Eccaparadoxides insularis Zone. A δ13Corg curve throughout the Borgholm Formation shows a general positive trend upsection without any distinctive excursion, suggesting that the Wuliuan Acadoparadoxides (Baltoparadoxides) oelandicus Superzone (the ‘Oelandicus beds’) of Öland is younger than the negative Redlichiid–Olenellid Extinction Carbon isotope Excursion (ROECE), which is known from near the top of Stage 4 and close to the traditional ‘Lower–Middle Cambrian boundary’ in several parts of the world.
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| 13. |
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| 14. |
- Andersson, Thord, et al.
(författare)
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Consistent intensity inhomogeneity correction in water-fat MRI
- 2015
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley-Blackwell. - 1053-1807 .- 1522-2586. ; 42:2
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To quantitatively and qualitatively evaluate the water-signal performance of the consistent intensity inhomogeneity correction (CIIC) method to correct for intensity inhomogeneitiesMETHODS: Water-fat volumes were acquired using 1.5 Tesla (T) and 3.0T symmetrically sampled 2-point Dixon three-dimensional MRI. Two datasets: (i) 10 muscle tissue regions of interest (ROIs) from 10 subjects acquired with both 1.5T and 3.0T whole-body MRI. (ii) Seven liver tissue ROIs from 36 patients imaged using 1.5T MRI at six time points after Gd-EOB-DTPA injection. The performance of CIIC was evaluated quantitatively by analyzing its impact on the dispersion and bias of the water image ROI intensities, and qualitatively using side-by-side image comparisons.RESULTS: CIIC significantly ( P1.5T≤2.3×10-4,P3.0T≤1.0×10-6) decreased the nonphysiological intensity variance while preserving the average intensity levels. The side-by-side comparisons showed improved intensity consistency ( Pint≤10-6) while not introducing artifacts ( Part=0.024) nor changed appearances ( Papp≤10-6).CONCLUSION: CIIC improves the spatiotemporal intensity consistency in regions of a homogenous tissue type.
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| 15. |
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| 16. |
- Borga, Magnus, et al.
(författare)
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Improvement in Magnetic Resonance Imaging Relating to Correction of Chemical Shift Artifact and Intensity Inhomogeneity
- 2011
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Patent (populärvet., debatt m.m.)abstract
- Present invention discloses systems and methods for improvement of magnetic resonance images. Correction of a chemical shift artefact in an image acquired from a magnetic resonance imaging system is obtained by a system and a method involving iterative - compensation for the misregistration effect in an image domain. Correction of an intensity inhomogeneity in such images is obtained by a system and a method involving locating voxels corresponding to pure adipose tissue and estimating correction field from these points.
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| 17. |
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| 18. |
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| 19. |
- Brandejsky, Vaclav, et al.
(författare)
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Phosphorus-31: A table-top method for 3D B1-field amplitude and phase measurements
- 2024
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : ELSEVIER. - 0005-2736 .- 1879-2642. ; 1866:4
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Tidskriftsartikel (refereegranskat)abstract
- A novel method of high -spatial -resolution, 3D B1 -field distribution measurements is presented. The method is independent of the MR -scanner, and it allows for automated acquisitions of complete maps of all magnetic field vector components for both proton and heteronuclear MR coils of arbitrary geometrical shapes. The advantage of the method proposed here, compared with methods based on measurements with an MR -scanner, is that a complete image of both receive and transmit B1 -fields, including the phase of the B1 -field, can be acquired. The B1 field maps obtained in this manner can be used for absolute quantification of metabolites in MRS experiments, as well as for intensity compensations in imaging experiments, both of which are important concepts in biological and medical MR applications. Another use might be in coil development and testing. A comparison with B1 field magnitude maps obtained with an MR -scanner was included to validate the accuracy of the proposed method.
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| 20. |
- Brorsson, Camilla, et al.
(författare)
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Liver resection is not associated with decreased cortisol levels.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: Adrenal hormones are synthesized from cholesterol, produced and stored in the liver. Liver failure has been reported to be associated with adrenal insufficiency. A possible mechanism could be a limited supply of substrate for cortisol synthesis. The aims of this study was to evaluate the occurrence of total serum cortisol <200 nmol/L after major liver resection (≥ 30%) and other major surgery (hemicolectomy) and to assess associations between cholesterol and cortisol levels after liver resection.Methods: Prospective, observational study. 40 patients were included (major liver resection n=15, hemicolectomy n=25). Serum and salivary cortisol were followed from morning before surgery up to five days postoperatively. Sulphated dehydroepiandrosterone (DHEAS) and lipids (cholesterol, low density lipoproteins, high density lipoproteins and triglycerides) were obtained in liver resection patients.Results: 8/25 (32%, hemicolectomy patients), and 3/15 (20%, liver resection patients) had serum cortisol <200 nmol/L. Neither hemicolectomy nor liver resection was significantly associated with serum cortisol <200 nmol/L, p=0.49. Serum cortisol <200 nmol/L was not significantly associated with lipids below normal limits, (cholesterol; p=1.0 day 1, p=0.46 day 4, LDL; p=0.56 day 1, p=1.0 day 4, and HDL; p=0.27 day 1, p=1.0 day 4). Serum and salivary cortisol correlated significantly (rs=0.83, p<0.0001, hemicolectomy, rs=0.80, p<0.0001, liver resection).Conclusion: Serum cortisol levels <200 nmol/L was found in 32% (hemicolectomy) and 20% (liver resection) postoperatively. Compared to after hemicolectomy, serum cortisol <200 nmol/L was not significantly more common after liver resection. Lipids below normal limits were not associated with serum cortisol <200 nmol/L after liver resection.
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