| 1. |
- Gong, Jing, et al.
(författare)
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A stable and efficient hybrid scheme for viscous problems in complex geometries
- 2007
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Ingår i: Journal of Computational Physics. - Uppsala : Elsevier BV. - 0021-9991 .- 1090-2716. ; 226:2, s. 1291-1309
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a stable hybrid scheme for viscous problems. The hybrid method combines the unstructured finite volume method with high-order finite difference methods on complex geometries. The coupling procedure between the two numerical methods is based on energy estimates and stable interface conditions are constructed. Numerical calculations show that the hybrid method is efficient and accurate.
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| 2. |
- Hedenus, Michael, et al.
(författare)
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Addition of intravenous iron to epoetin beta increases hemoglobin response and decreases epoetin dose requirement in anemic patients with lymphoproliferative malignancies : a randomized multicenter study
- 2007
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Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 21:4, s. 627-632
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Tidskriftsartikel (refereegranskat)abstract
- This randomized study assessed if intravenous iron improves hemoglobin (Hb) response and permits decreased epoetin dose in anemic (Hb 9 - 11 g/dl), transfusion-independent patients with stainable iron in the bone marrow and lymphoproliferative malignancies not receiving chemotherapy. Patients (n = 67) were randomized to subcutaneous epoetin beta 30 000 IU once weekly for 16 weeks with or without concomitant intravenous iron supplementation. There was a significantly (P < 0.05) greater increase in mean Hb from week 8 onwards in the iron group and the percentage of patients with Hb increase >= 2 g/dl was significantly higher in the iron group (93%) than in the no-iron group (53%) (per-protocol population; P < 0.001). Higher serum ferritin and transferrin saturation in the iron group indicated that iron availability accounted for the Hb response difference. The mean weekly patient epoetin dose was significantly lower after 13 weeks of therapy (P < 0.029) and after 15 weeks approximately 10 000 IU (425%) lower in the iron group, as was the total epoetin dose (P = 0.051). In conclusion, the Hb increase and response rate were significantly greater with the addition of intravenous iron to epoetin treatment in iron-replete patients and a lower dose of epoetin was required.
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| 3. |
- Johansson, Björn, et al.
(författare)
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Visual and optical performance of the Akreos Adapt Advanced Optics and Tecnis Z9000 intraocular lenses. Swedish multicenter study
- 2007
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Ingår i: Journal of cataract and refractive surgery. - : Ovid Technologies (Wolters Kluwer Health). - 0886-3350 .- 1873-4502. ; 33:9, s. 1565-1572
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To compare the subjective visual and objective optical performance of 2 aspherical intraocular lenses (lOLs), the Akreos Adapt Advanced Optics (AO) (Bausch & Lomb, Inc.) and the Tecnis Z9000 (Advanced Medical Optics, Inc.). SETTING: Four university hospitals in Sweden. METHODS: This study comprised 80 patients, 20 each from 4 university hospital centers in Sweden. All patients had bilateral clear corneal phacoemulsification with implantation of an Akreos Adapt AO IOL in 1 eye and Tecnis Z9000 IOL in the other eye according to a randomization protocol. Preoperatively, 90% contrast Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity was measured and the mesopic pupil sizes were determined. Ten to 12 weeks postoperatively, 12.5% and 90% contrast ETDRS visual acuities and photopic and mesopic Functional Acuity Contrast Test chart contrast sensitivities were determined. Wavefront analysis was performed with the Zywave II aberrometer (Bausch & Lomb, Inc.), and a questionnaire on the subjective quality of vision was completed by each patient. RESULTS: The Akreos AO IOL and Tecnis Z9000 IOL produced similar high- and low-contrast visual acuities as well as photopic and mesopic contrast sensitivities. The Tecnis Z9000 IOL resulted in lower spherical aberrations of the eye (mean 0.05 ± 0.13 μm versus 0.35 ± 0.13 μm root mean square, 6.0 mm pupil) (P<.001); however, the Akreos AO IOL provided a larger depth of field (mean 1.22 diopter [D] ± 0.48 [SD] versus 0.86 ± 0.50 D, 6.0 mm pupil) (P<.001). Patient satisfaction was generally high, although 68.8% of the patients reported some type of visual disturbance postoperatively. Twenty-eight percent of patients reported better subjective visual quality in the Akreos AO eye and 14%, in the Tecnis Z9000 eye (P<.0001). Accordingly, 33% perceived more visual disturbances in the Tecnis Z9000 eye and 11%, in the Akreos AO eye (P<.0001). CONCLUSIONS: Maximum reduction of spherical aberration did not maximize subjective visual quality. The higher perceived quality of vision with the Akreos AO IOL could be because of differences in depth of field, lOL material, or IOL design.
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| 4. |
- Björling, Gunilla, Docent, et al.
(författare)
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Clinical use and material wear of polymeric tracheostomy tubes
- 2007
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Ingår i: The Laryngoscope. - : Lippincott Williams & Wilkins. - 0023-852X .- 1531-4995. ; 117:9, s. 1552-1559
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The objectives were to compare the duration of use of polymeric tracheostomy tubes, i.e., silicone (Si), polyvinyl chloride (PVC), and polyurethane (PU), and to determine whether surface changes in the materials could be observed after 30 days of patient use. METHODS: Data were collected from patient and technical records for all tracheostomized patients attending the National Respiratory Center in Sweden. In the surface study, 19 patients with long-term tracheostomy were included: six with Bivona TTS Si tubes, eight with Shiley PVC tubes, and five with Trachoe Twist PU tubes. All tubes were exposed in the trachea for 30 days before being analyzed by scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). New tubes and tubes exposed in phosphate-buffered saline were used as reference. RESULTS: Si tubes are used for longer periods of time than those made of PVC (P < .0001) and PU (P = .021). In general, all polymeric tubes were used longer than the recommended 30-day period. Eighteen of the 19 tubes exposed in patients demonstrated, in one or more areas of the tube, evident surface changes. The morphologic changes identified by SEM correlate well with the results obtained by ATR-FTIR. CONCLUSIONS: Si tracheostomy tubes are in general used longer than those made of PVC and PU. Most of the tubes exposed in the trachea for 30 days suffered evident surface changes, with degradation of the polymeric chains as a result.
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| 5. |
- Börjesson, Maria, 1974-, et al.
(författare)
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The value of time of car drivers choosing route: evidence from the Stockholm congestion charging trial
- 2007
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Ingår i: Proceedings of the European Transport Conference. - Leiden, Netherlands. ; , s. 14-
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Konferensbidrag (refereegranskat)abstract
- In applied travel demand forecasting (including network modeling), congestion charges are generally assumed to affect travelers in the same way as fuel costs and other travel costs do. However, there are several reasons to believe that congestion charges affect drivers differently than for example fuel costs: for exampel, it is more “visible”, since you (as a rule) pay each time you pass a cordon (or equivalent), and it is often connected with a certain amount of hassle to actually pay the charge (calling a customer service, for example). Moreover, the way car drivers actually weigh travel time versus monetary cost when they choose route is largely unknown, since time and monetary cost are in general so correlated (as opposed to values of time in mode choice etc.). Data from the Stockholm congestion charging trial allow us to explore this question in detail. Car drivers traveling between the northern part of the county and the southern part could choose either to go through the cordon (paying two charges – 20-40 SEK depending on the time of day) or use the Essinge bypass, which was free of charge – a considerable detour for some trip relations. We use a large panel travel survey conducted before and during the charging trial to estimate the charging cost sensitivity compared to fuel cost sensitivity, and also estimate the actual value of time car drivers reveal when choosing route. Note that due to e.g. selection bias or travelers’ imperfect information about costs, this value of tme may differ from the average value of time for all travelers and also from the average value time for car drivers. The results is very applicable, in that it is easily incorporated into widely used traffic models (network equilibrium models or equivalent), allowing us to make more precise forecasts of the effects of congestion charges. It should also allow us to make more precise route choice modeling in other cases where routes have clearly different monetary costs.
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| 6. |
- Castleton, Christopher, 1969-, et al.
(författare)
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Correlations between magnetic properties and bond formation in Rh-MgO(001)
- 2007
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 601:5, s. 1218-1230
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of first principles calculations for the magnetism of Rh adlayers on MgO(001), at three different adsorption sites and three different coverages, corresponding to 1, 1/2 and 1/8 monolayers. Finite magnetization is found in all cases except that of one Rh monolayer above the oxygen site, which is also the most stable. We examine how the magnetization changes as a function of the Rh-surface distance and relate this to changes in the real-space charge density and in the density of states (DOS) as the Rh adlayer interacts with the surface. We find that increasing either the Rh-Rh interaction strength or the Rh-surface interaction strength leads to reduced magnetization, while increasing the former drives a crossover from localized (atomic) to itinerant magnetism. Neither the magnetic transition itself, nor the localized-to-itinerant magnetism crossover, is found to be directly related to the formation of Rh-surface bonds. From a practical point of view, we predict that magnetism in the Rh-MgO(001) system is most likely to be found experimentally at reduced coverages and at low temperatures.
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| 7. |
- Castleton, Christopher, 1969-, et al.
(författare)
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Tuning LDA+U for electron localization and structure at oxygen vacancies in ceria
- 2007
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 127:24
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Tidskriftsartikel (refereegranskat)abstract
- We examine the real space structure and the electronic structure (particularly Ce4f electron localization) of oxygen vacancies in CeO2 (ceria) as a function of U in density functional theory studies with the rotationally invariant forms of the LDA+U and GGA+U functionals. The four nearest neighbor Ce ions always relax outwards, with those not carrying localized Ce4f charge moving furthest. Several quantification schemes show that the charge starts to become localized at U approximate to 3 eV and that the degree of localization reaches a maximum at similar to 6 eV for LDA+U or at similar to 5.5 eV for GGA+U. For higher U it decreases rapidly as charge is transferred onto second neighbor O ions and beyond. The localization is never into atomic corelike states; at maximum localization about 80-90% of the Ce4f charge is located on the two nearest neighboring Ce ions. However, if we look at the total atomic charge we find that the two ions only make a net gain of (0.2-0.4)e each, so localization is actually very incomplete, with localization of Ce4f electrons coming at the expense of moving other electrons off the Ce ions. We have also revisited some properties of defect-free ceria and find that with LDA+U the crystal structure is actually best described with U=3-4 eV, while the experimental band structure is obtained with U=7-8 eV. (For GGA+U the lattice parameters worsen for U > 0 eV, but the band structure is similar to LDA+U.) The best overall choice is U approximate to 6 eV with LDA+U and approximate to 5.5 eV for GGA+U, since the localization is most important, but a consistent choice for both CeO2 and Ce2O3, with and without vacancies, is hard to find.
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| 8. |
- Castro, Vasco, et al.
(författare)
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NMR studies of membranes composed of glycolipids and phospholipids
- 2007
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642. ; 1768, s. 2432-2437:1768, s. 2432-2437
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Tidskriftsartikel (refereegranskat)abstract
- Lipid membranes composed of monogalactosyldiacylglycerol (MGDG) and dimyristoylphosphatidylcholine (DMPC) were studied by means of NMR spectroscopy. The macroscopic phase behaviour was investigated by P-31 NMR under stationary conditions, whereas microscopic properties such as segmental ordering were probed by two-dimensional H-1-C-13 separated local field experiments under magic-angle spinning conditions. Our results clearly show that ordering/disordering effects occur for the headgroups as well as for the acyl chains when the sample composition is varied. In particular, the H-1-C-13 dipolar couplings within the galactose headgroup of MGDG exhibited significant concentration dependence.
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| 9. |
- Finnveden, Göran, et al.
(författare)
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Flexible and robust strategies for waste management in Sweden
- 2007
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 27:8, s. s1-S8
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Tidskriftsartikel (refereegranskat)abstract
- Treatment of solid waste continues to be on the political agenda. Waste disposal issues are often viewed from an environmental perspective, but economic and social aspects also need to be considered when deciding on waste strategies and policy instruments. The aim of this paper is to suggest flexible and robust strategies for waste management in Sweden, and to discuss different policy instruments. Emphasis is on environmental aspects, but social and economic aspects are also considered. The results show that most waste treatment methods have a role to play in a robust and flexible integrated waste management system, and that the waste hierarchy is valid as a rule of thumb from an environmental perspective. A review of social aspects shows that there is a general willingness among people to source separate wastes. A package of policy instruments can include landfill tax, an incineration tax which is differentiated with respect to the content of fossil fuels and a weight based incineration tax, as well as support to the use of biogas and recycled materials.
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| 10. |
- Hao, Xiaojin, et al.
(författare)
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Angiogenic effects of sequential release of VEGF-A(165) and PDGF-BB with alginate hydrogels after myocardial infarction
- 2007
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Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 28, s. 612-612
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study investigates whether local sequential delivery of vascular endothelial growth factor-A(165) (VEGF-A(165)) followed by platelet-derived growth factor-BB (PDGF-BB) with alginate hydrogels could induce an angiogenic effect and functional improvement greater than single factors after myocardial infarction. Methods: Alginate hydrogels were prepared by combining high and low molecular weight alginate. Growth factor release rates were monitored over time in vitro with I-125-labelled VEGF-A(165) and PDGF-BB included in the gels. One week after myocardial infarction was induced in Fisher rats, gels with VEGF-A(165), PDGF-BB, or both were given intra-myocardially along the border of the myocardial infarction. Vessel density was analysed in hearts and cardiac function was determined by Tissue Doppler Echocardiography. In addition, the angiogenic effect of sequenced delivery was studied in vitro in aortic rings from C57B1/6 mice. Results: Alginate gets were capable of delivering VEGF-A(165) and PDGF-BB in a sustainable manner, and PDGF-BB was released more slowly than VEGF-A(165). Sequential growth factor administration led to a higher density of alpha-actin positive vessels than single factors, whereas no further increment was found in capillary density. Sequential protein delivery increased the systolic velocity-time integral and displayed a superior effect than single factors. In the aortic ring model, sequential delivery led to a higher angiogenic effect than single factor administration. Conclusions: The alginate hydrogel is an effective and promising injectable delivery system in a myocardial infarction model. Sequential growth factor delivery of VEGF-A(165) and PDGF-BB induces mature vessels and improves cardiac function more than each factor singly. This may indicate clinical utility.
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