| 11. |
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| 12. |
- Farrokhnia, Nasim, et al.
(författare)
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Experimental treatment for focal hyperglycemic ischemic brain injury in the rat
- 2005
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 167:2, s. 310-314
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Tidskriftsartikel (refereegranskat)abstract
- Hyperglycemia aggravates ischemic brain injury, possibly due to the activation of signaling pathways involving reactive oxygen species, Src and mitogen-activated protein kinases. The aim of this study was to investigate the effects of the spin trap agent alpha-phenyl-N-tert-butyl nitrone (PBN), the Src family kinase inhibitor PP2 and the MEK1-inhibitor U0126 on focal hyperglycemic ischemic brain injury. Temporary middle cerebral artery occlusion (90 min) was induced in four groups of rats (PBN, PP2, and U0126 vs. control). Neurological testing and tetrazolium red staining were performed after 1 day. PBN decreased the infarct volume by 70% compared with the control (P<0.05) and a tendency towards reduced infarcts was seen in the PP2 or U0126 groups. Furthermore, neurological testing was consistent with the volumetric analysis. In conclusion, PBN appears to be a potential neuroprotective agent in hyperglycemic, focal ischemic brain injury, while the efficacy of PP2 and U0126 could not be confirmed by the present data.
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| 13. |
- Henricsson, Fredrik, et al.
(författare)
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Aspects on the analysis of (210)Po.
- 2011
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 102:5, s. 415-419
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Tidskriftsartikel (refereegranskat)abstract
- There has been little development regarding analysis of polonium (Po) in environmental samples since the 1960ies. This is due to the straightforward spontaneous deposition of this element on silver (Ag), nickel (Ni) or copper (Cu) without any radiochemical separation. For many years, no radiochemical yield determinant was used and it was generally supposed that the yield was 100% after two depositions. Counting was often done using ZnS scintillation counter coupled to a photomultiplier tube. However, the use of the yield determinants (208)Po and (209)Po and the development of alpha spectrometry showed that the yield was lower. Furthermore, the tendency of Po to volatilize at low temperatures constrains the sample preparation techniques; dry-ashing cannot be used. But during the wet-ashing procedure, there are still some losses. The aim of this study was to evaluate the Po losses during wet-ashing by the use of a double-tracer technique. We have found that the losses were about 30% when open glass beakers were used and about 17% when the samples were digested in microwave oven. When long-necked bottles (Kjeldahl flasks) were used, a loss of about 20% was registered. It has also been observed that (210)Pb to some extent is plating out together with its daughter nuclide Po during the electrochemical deposition. This will result in a systematic error since an unknown amount of supported (210)Po will be produced from the (210)Pb decay depending on the fraction of (210)Pb being deposited on the disc and the waiting time between deposition and measurement of the sample. A further consequence of this is that in the assessment of the (210)Pb content in the sample, very often the remaining liquid is stored after deposition for build-up of (210)Po. Since some (210)Pb is lost on the disc, the result for (210)Pb will be too low. Both these systematic errors give rise to a too high (210)Po/(210)Pb ratio. The fraction of (210)Pb which is plating out has been assessed in this study for different matrices and is about 50-90%. During the measurement by solid state Si-detectors, some Po is evaporated in the vacuum conditions contaminating the detectors. Experiments have here been done by heating the discs after deposition which indicate that less Po is evaporated from Ag than from Ni. The losses from Ag are less than that from the other metals probably due to a deeper penetration into the surface of Po. We conclude that in most aspects, Ag is better to use than the other plating metals.
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| 14. |
- Henriksson, Manne, 1987-, et al.
(författare)
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Implementation of an Optimal Look-Ahead Controller in a Heavy-Duty Distribution Vehicle
- 2019
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Ingår i: Proceedings 2019 IEEE Intelligent Vehicles Symposium (IV). ; , s. 2202-2207
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Konferensbidrag (refereegranskat)abstract
- Controlling the longitudinal movement of heavy-duty vehicles based on optimal control can be a cost-efficient way of reducing their fuel consumption. Such controllers today mainly exist for vehicles in haulage applications, in which the velocity is allowed to deviate from a constant set-speed. For distribution vehicles, which is the focus of this paper, the desired and required velocity has large variations, which makes the situation more complex. This paper describes the implementation of an optimal controller in a real heavy-duty distribution vehicle. The optimal control problem is solved offline as a Mixed Integer Quadratic Program, which yields reference trajectories that are tracked online in the vehicle. Some important steps in the procedure of the implementation are, except for designing the controller: developing a positioning system for the test track where the experiments are performed, estimating the parameters of the resistive forces, and setting the velocity constraints. Simulations show a potential of 10% reduction in fuel consumption without increasing the trip time. Experiments are then performed in a Scania truck, with the optimal solution as reference for the existing cruise control functions in the vehicle. It is concluded that in order to verify the fuel savings experimentally, the low-level controllers in the vehicle must be modified such that the tracking error is decreased.
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| 15. |
- Henriksson, Manne, 1987-, et al.
(författare)
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Optimal Freewheeling Control of a Heavy-Duty Vehicle Using Mixed Integer Quadratic Programming
- 2020
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Ingår i: IFAC PAPERSONLINE. - : Elsevier BV. - 2405-8963. ; , s. 13809-13815
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Konferensbidrag (refereegranskat)abstract
- Improving the powertrain control of heavy-duty vehicles can be an efficient way to reduce the fuel consumption and thereby reduce both the operating cost and the environmental impact. One way of doing so is by using information about the upcoming driving conditions, known as look-ahead information, in order to coast in gear or to use freewheeling. Controllers using such techniques today mainly exist for vehicles in highway driving. This paper therefore targets how such control can be applied to vehicles with more variations in their velocity. The driving mission of such a vehicle is here formulated as an optimal control problem. The control variables are the tractive force, the braking force, and a Boolean variable representing closed or open powertrain. The problem is solved by a model predictive controller, which at each iteration solves a mixed integer quadratic program. The fuel consumption is compared for four different control policies: a benchmark following the reference of the driving cycle, look-ahead control without freewheeling, freewheeling with the engine idling, and freewheeling with the engine turned off. Simulations on a driving cycle with a varying velocity profile show the potential of saving 11 %, 19 %, and 23% respectively for the control policies compared with the benchmark, in all cases without increasing the trip time. Copyright
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| 16. |
- Hultdin, Magnus, et al.
(författare)
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Association between telomere length and V-H gene mutation status in chronic lymphocytic leukaemia : clinical and biological implications
- 2003
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Ingår i: British Journal of Cancer. - London : Nature Publishing Group. - 0007-0920 .- 1532-1827. ; 88:4, s. 593-598
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Tidskriftsartikel (refereegranskat)abstract
- The immunoglobulin V-H gene mutation status can divide B-cell chronic lymphocytic leukaemia (CLL) into two entities with a different clinical course. Cases with unmutated V-H genes, considered to evolve from pregerminal centre (GC) cells, have a worse outcome compared to cases showing mutated VH genes, that is, post-GC derived. Also, telomere length has been reported to be of prognostic significance in CLL. Interestingly, telomerase becomes activated during the GC reaction and an elongation of the telomeres occurs in GC B cells. We performed telomere length and VH gene analysis in a series of 61 CLL cases, in order to investigate if the unique telomere lengthening shown in GC B cells could reflect the telomere status in the two subsets of mutated and unmutated CLL. A novel association was found between VH gene mutation status and telomere length, since significantly shorter telomeres were demonstrated in the unmutated group compared to the mutated group (mean length 4.3 vs 63 kbp). Shorter telomeres also constituted a subgroup with a worse prognosis than cases with longer telomeres (median survival 59 vs 159 months), Furthermore, the I-g gene sequence data revealed that samples with high mutations frequency (> 6%) had long telomeres (similar to 8 kbp). Thus, both the telomere and VH gene mutation status in CLL appear linked, which may reflect the proliferative history of the clonal cells with regard to the GC reaction. (C) 2003 Cancer Research UK.
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| 17. |
- Hultdin, Magnus, et al.
(författare)
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Replication timing of human telomeric DNA and other repetitive sequences analyzed by fluorescence in situ hybridization and flow cytometry
- 2001
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Ingår i: Experimental Cell Research. - : Elsevier. - 0014-4827. ; 271, s. 223-229
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Tidskriftsartikel (refereegranskat)abstract
- The replication timing of telomeres seems to differ between species. Yeast telomeres are late replicating, whereas limited data from very few human cell lines have indicated telomere replication throughout S phase. In the present study a series of permanent cell lines and patient samples was investigated using a flow cytometric approach for telomere length determination based on in situ hybridization using peptide nucleic acid probes and DNA staining. This method permits selective analysis of cells in specific phases of the cell cycle without perturbation of the cell cycle machinery. The timing of replication of telomeric C(3)TA(2) and T(2)AG(3) repeats was found to differ between individual samples and could precede or be concomitant with the replication of bulk DNA. Replication of the T(2)AG(3) strand seemed to occur somewhat later than that of the C(3)TA(2) strand in some samples. (GTG)(n) and other repetitive sequences generally showed a replication pattern similar to that of the bulk of DNA with slightly individual differences, whereas centromeric DNA repeats consistently replicated within a short time frame in late S phase. The apparent variability in replication timing seen for telomeric DNA might suggest individual differences in firing of replication origins.
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| 18. |
- Hultdin, Magnus, et al.
(författare)
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Telomere analysis by fluorescence in situ hybridization and flow cytometry
- 1998
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Ingår i: Nucleic Acids Research. - Oxford : Oxford University Press. - 0305-1048 .- 1362-4962. ; 26:16, s. 3651-3656
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Tidskriftsartikel (refereegranskat)abstract
- Determination of telomere length is traditionally performed by Southern blotting and densitometry, giving a mean telomere restriction fragment (TRF) value for the total cell population studied. Fluorescence in situ hybridization (FISH) of telomere repeats has been used to calculate telomere length, a method called quantitative (Q)-FISH, We here present a quantitative flow cytometric approach, Q-FISHFCM, for evaluation of telomere length distribution in individual cells based on in situ hybridization using a fluorescein-labeled peptide nucleic acid (PNA) (CCCTAA)(3) probe and DMA staining with propidium iodide, A simple and rapid protocol with results within 30 h was developed giving high reproducibility, One important feature of the protocol was the use of an internal cell line control, giving an automatic compensation for potential differences in the hybridization steps. This protocol was tested successfully on cell lines and clinical samples from bone marrow, blood, lymph nodes and tonsils. A significant correlation was found between Southern blotting and Q-FISHFCM telomere length values (P = 0.002), The mean sub-telomeric DNA length of the tested cell lines and clinical samples was estimated to be 3.2 kbp, With the Q-FISHFCM method the fluorescence signal could be determined in different cell cycle phases, indicating that in human cells the vast majority of telomeric DNA is replicated early in S phase.
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| 19. |
- Johannesson, T, et al.
(författare)
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Reliability of Protection Systems - Operational Experiences 1976-2002
- 2004
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Ingår i: 8th International Conference on Development in Power System Protection. - 0863413854 ; 1, s. 303-306
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Konferensbidrag (refereegranskat)abstract
- This paper presents the results of an extensive survey on incorrect protection operations performed in Sweden on an electric power system owned by Sydkraft. The survey is based on disturbance reports and special investigation reports for the period 1976-2002. The results indicate the occurrence of the major types and causes of incorrect protection operations that have been revealed at disturbances in the electric power system under study.
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| 20. |
- Johansson, Kari, et al.
(författare)
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Outcomes of pregnancy after bariatric surgery
- 2015
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 372:9, s. 814-824
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Maternal obesity is associated with increased risks of gestational diabetes, large-for-gestational-age infants, preterm birth, congenital malformations, and stillbirth. The risks of these outcomes among women who have undergone bariatric surgery are unclear.METHODS: We identified 627,693 singleton pregnancies in the Swedish Medical Birth Register from 2006 through 2011, of which 670 occurred in women who had previously undergone bariatric surgery and for whom presurgery weight was documented. For each pregnancy after bariatric surgery, up to five control pregnancies were matched for the mother's presurgery body-mass index (BMI; we used early-pregnancy BMI in the controls), age, parity, smoking history, educational level, and delivery year. We assessed the risks of gestational diabetes, large-for-gestational-age and small-for-gestational-age infants, preterm birth, stillbirth, neonatal death, and major congenital malformations.RESULTS: Pregnancies after bariatric surgery, as compared with matched control pregnancies, were associated with lower risks of gestational diabetes (1.9% vs. 6.8%; odds ratio, 0.25; 95% confidence interval [CI], 0.13 to 0.47; P< 0.001) and large-for-gestational-age infants (8.6% vs. 22.4%; odds ratio, 0.33; 95% CI, 0.24 to 0.44; P< 0.001). In contrast, they were associated with a higher risk of small-for-gestational-age infants (15.6% vs. 7.6%; odds ratio, 2.20; 95% CI, 1.64 to 2.95; P< 0.001) and shorter gestation (273.0 vs. 277.5 days; mean difference -4.5 days; 95% CI, -2.9 to -6.0; P< 0.001), although the risk of preterm birth was not significantly different (10.0% vs. 7.5%; odds ratio, 1.28; 95% CI, 0.92 to 1.78; P = 0.15). The risk of stillbirth or neonatal death was 1.7% versus 0.7% (odds ratio, 2.39; 95% CI, 0.98 to 5.85; P = 0.06). There was no significant between-group difference in the frequency of congenital malformations.CONCLUSIONS: Bariatric surgery was associated with reduced risks of gestational diabetes and excessive fetal growth, shorter gestation, an increased risk of small-for-gestational-age infants, and possibly increased mortality.
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