| 1. |
- Nordström, Johan, 1992-, et al.
(författare)
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A GPU code for analytic continuation through a sampling method
- 2016
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Ingår i: SoftwareX. - : Elsevier. - 2352-7110. ; 5, s. 178-182
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Tidskriftsartikel (refereegranskat)abstract
- We here present a code for performing analytic continuation of fermionic Green’s functions and self-energies as well as bosonic susceptibilities on a graphics processing unit (GPU). The code is based on the sampling method introduced by Mishchenko et al. (2000), and is written for the widely used CUDA platform from NVidia. Detailed scaling tests are presented, for two different GPUs, in order to highlight the advantages of this code with respect to standard CPU computations. Finally, as an example of possible applications, we provide the analytic continuation of model Gaussian functions, as well as more realistic test cases from many-body physics.
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| 2. |
- Bentzer, Peter, et al.
(författare)
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The volume-expanding effects of autologous liquid stored plasma following hemorrhage.
- 2012
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 1502-7686 .- 0036-5513. ; 72:6, s. 490-494
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Tidskriftsartikel (refereegranskat)abstract
- Background: Plasma use has increased since studies have suggested that early treatment with blood components in trauma with severe hemorrhage may improve outcome. Plasma is also commonly used to correct coagulation disturbances in non-bleeding patients. Little is known about the effects of plasma transfusion on plasma volume. We report a prospective interventional study in which the plasma volume-expanding effect of autologous plasma was investigated after a controlled hemorrhage. Methods: Plasma obtained by plasmapheresis from nine healthy regular blood donors was stored at 2-6°C. Five weeks after donation the subjects were bled of 600 ml and then transfused with 600 ml of autologous plasma. Plasma volume was estimated using (125)I-albumin before and after bleeding, and immediately after plasma transfusion. Plasma volume changes were then estimated by measuring changes in hematocrit during the following 3-h period. Results: Estimated plasma volume after bleeding was 3170 ± 320 ml and 3690 ± 380 ml (mean ± standard deviation) immediately following the transfusion of plasma (p 0.05). This increase in plasma volume corresponds to 86 ± 13% of the infused volume. Three hours after transfusion, plasma volume was still 3680 ± 410 ml. Conclusions: Stored liquid plasma has a plasma volume expanding effect up to 86% of its infused volume with a duration of at least 3 h.
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| 3. |
- Ekbäck, Gustav, et al.
(författare)
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Tranexamic Acid Reduces Blood Loss in Total Hip Replacement Surgery
- 2000
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Ingår i: Anesthesia and Analgesia. - 0003-2999 .- 1526-7598. ; 91:5, s. 1124-1130
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Tidskriftsartikel (refereegranskat)abstract
- Intraoperatively administered, tranexamic acid (TA) does not reduce bleeding in total hip replacement (THR). Therefore, its prophylactic use was attempted in the present study because this has been shown to be more effective in cardiac surgery. We investigated 40 patients undergoing THR in a prospective, randomized, double-blinded study. Twenty patients received TA given in two bolus doses of 10 mg/kg each, the first just before surgical incision and the second 3 h later. In addition, a continuous infusion of TA, 1.0 mg · kg−1 · h−1 for 10 h, was given after the first bolus dose. The remaining 20 patients formed a control group. Both groups used preoperative autologous blood donation and intraoperative autotransfusion. Intraoperative bleeding was significantly less (P = 0.001) in the TA group compared with the control group (630 ± 220 mL vs 850 ± 260 mL). Postoperative drainage bleeding was correspondingly less (P = 0.001) (520 ± 280 vs 920 ± 410 mL). Up to 10 h postoperatively, plasma D-dimer concentration was halved in the TA group compared with the control group. One patient in each group had an ultrasound-verified late deep vein thrombosis. In conclusion, we found TA, administrated before surgical incision, to be efficient in reducing bleeding during THR.
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| 4. |
- Jana, Somnath, et al.
(författare)
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Charge disproportionate antiferromagnetism at the verge of the insulator-metal transition in doped LaFeO3
- 2019
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 99:7
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Tidskriftsartikel (refereegranskat)abstract
- We explore the effects of electron doping in lanthanum ferrite, LaFeO3 by doping Mo at the Fe sites. Based on magnetic, transport, scanning tunneling spectroscopy, and x-ray photoelectron spectroscopy measurements, we find that the large gap, charge-transfer, antiferromagnetic (AFM) insulator LaFeO3 becomes a small gap AFM band insulator at low Mo doping. With increasing doping concentration, Mo states, which appear around the Fermi level, is broadened and become gapless at a critical doping of 20%. Using a combination of calculations based on density functional theory plus Hubbard U (DFT+U) and x-ray absorption spectroscopy measurements, we find that the system shows charge disproportionation (CD) in Fe ions at 25% Mo doping, where two distinct Fe sites, having Fe2+ and Fe3+ nominal charge states appear. A local breathing-type lattice distortion induces the charge disproportionation at the Fe site without destroying the antiferromagnetic order. Our combined experimental and theoretical investigations establish that the Fe states form a CD antiferromagnet at 25% Mo doping, which remains insulating, while the appearance of Mo states around the Fermi level is showing an indication towards the insulator-metal transition.
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| 5. |
- Jana, Somnath, et al.
(författare)
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Doping induced site-selective Mott insulating phase in LaFeO3
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Tailoring transport properties of strongly correlated electron systems in a controlled fashion counts among the dreams of materials scientists. In copper oxides, vary- ing the carrier concentration is a tool to obtain high- temperature superconducting phases. In manganites, dop- ing results in exotic physics such as insulator-metal tran- sitions (IMT), colossal magnetoresistance (CMR), orbital- or charge-ordered (CO) or charge-disproportionate (CD) states. In most oxides, antiferromagnetic order and CD phase is asssociated with insulating behavior. Here we re- port the realization of a unique physical state that can be induced by Mo doping in LaFeO3: the resulting metallic state is a site-selective Mott insulator where itinerant elec- trons evolving on low-energy Mo states coexist with local- ized carriers on the Fe sites. In addition, a local breathing- type lattice distortion induces charge disproportionation on the latter, without destroying the antiferromagnetic order. A state, combining antiferromangetism, metallic- ity and CD phenomena is rather rare in oxides and have utmost significance for future antiferromagnetic memory devices.
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| 6. |
- Jansohn, Erik, et al.
(författare)
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A pilot study on the applicability of thromboelastometry in detecting brain tumour-induced hypercoagulation
- 2017
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 77:4, s. 289-294
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Tidskriftsartikel (refereegranskat)abstract
- Patients with intracranial tumours have an increased risk of venous thromboembolism, particularly during the first month after neurosurgery. A proposed explanation for this increased risk, are procoagulant tumour-derived substances, such as tissue factor, usually measured in peripheral blood. The aim of the present study is to investigate whether a rotational thromboelastometry (ROTEM) can measure the procoagulative activity of tumour tissue. The study included 21 patients who were undergoing a craniotomy and complete tumour resection after written consent and ethical approval were obtained. Tumour tissue was biopsied during surgery and used for in vitro spiking of patients own citrated whole blood. Blood samples with or without spiking were analyzed with ROTEM using different activating reagents. ROTEM clotting time significantly decreased (p < .001), indicating a hypercoagulative response on clot initiation that was strongest for glioma tumours. However, ROTEM clot formation time was significantly prolonged (p < .001), which was an opposite response that indicated poor initial clot propagation. ROTEM maximum lysis was increased in the tumour tissue-spiked samples (p < .001), indicating a strong fibrinolytic activity in brain tumour tissue. Tissue extracts from intracranial tumours have both procoagulant and fibrinolytic effects that are detectable with ROTEM. Glioma tumours had the strongest hypercoagulative response in our in vitro model. Larger studies are necessary to test the clinical relevance and accuracy of tumour extract spiked viscoelastic tests to predict the individual patient risk for developing a thrombotic complication.
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| 7. |
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| 8. |
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| 9. |
- Keshavarz, Samara, et al.
(författare)
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Electronic structure, magnetism, and exchange integrals in transition-metal oxides : Role of the spin polarization of the functional in DFT+U calculations
- 2018
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Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 97:18
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Tidskriftsartikel (refereegranskat)abstract
- Density functional theory augmented with Hubbard-U corrections (DFT+U) is currently one of the most widely used methods for first-principles electronic structure modeling of insulating transition-metal oxides (TMOs). Since U is relatively large compared to bandwidths, the magnetic excitations in TMOs are expected to be well described by a Heisenberg model. However, in practice the calculated exchange parameters J(ij) depend on the magnetic configuration from which they are extracted and on the functional used to compute them. In this work we investigate how the spin polarization dependence of the underlying exchange-correlation functional influences the calculated magnetic exchange constants of TMOs. We perform a systematic study of the predictions of calculations based on the local density approximation plus U (LDA+U) and the local spin density approximation plus U (LSDA+U) for the electronic structures, total energies, and magnetic exchange interactions Jij extracted from ferromagnetic (FM) and antiferromagnetic (AFM) configurations of several transition-metal oxide materials. We report that for realistic choices of Hubbard U and Hund's J parameters, LSDA+U and LDA+U calculations result in different values of the magnetic exchange constants and band gap. The dependence of the band gap on the magnetic configuration is stronger in LDA+U than in LSDA+U and we argue that this is the main reason why the configuration dependence of Jij is found to be systematically more pronounced in LDA+U than in LSDA+U calculations. We report a very good correspondence between the computed total energies and the parametrized Heisenberg model for LDA+U calculations, but not for LSDA+U, suggesting that LDA+U is a more appropriate method for estimating exchange interactions.
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| 10. |
- Larsson, A., et al.
(författare)
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Comparison of point-of-care hemostatic assays, routine coagulation tests, and outcome scores in critically ill patients
- 2015
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Ingår i: Journal of critical care. - : W B SAUNDERS CO-ELSEVIER INC. - 0883-9441 .- 1557-8615. ; 30:5, s. 1032-1038
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purposes of the study are to compare point-of-care (POC) hemostatic devices in critically ill patients with routine laboratory tests and intensive care unit (ICU) outcome scoring assessments and to describe the time course of these variables in relation to mortality rate. Materials and methods: Patients admitted to the ICU with a prognosis of more than 3 days of stay were included. The POC devices, Multiplate platelet aggregometry, rotational thromboelastometry, and ReoRox viscoelastic tests, were used. All variables were compared between survivors and nonsurvivors. Point-of-care results were compared to prothrombin time, activated partial thromboplastin time, platelet count, fibrinogen concentration, and Sequential Organ Failure Assessment score and Simplified Acute Physiology Score 3. Results: Blood was sampled on days 0 to 1, 2 to 3, and 4 to 10 from 114 patients with mixed diagnoses during 237 sampling events. Nonsurvivors showed POC and laboratory signs of hypocoagulation and decreased fibrinolysis over time compared to survivors. ReoRox detected differences between survivors and nonsurvivors better than ROTEM and Multiplate. Conclusions: All POC and routine laboratory tests showed a hypocoagulative response in nonsurvivors compared to survivors. ReoRox was better than ROTEM and Multiplate at detecting differences between surviving and nonsurviving ICU patients. However, Simplified Acute Physiology Score 3 showed the best association to mortality outcome.
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