| 1. |
- Bartoszek, Krzysztof, 1984-, et al.
(författare)
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Influenza differentiation and evolution
- 2010
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Ingår i: Acta Physica Polonica B Proceedings Supplement. ; 3:2, s. 417-452
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Konferensbidrag (refereegranskat)abstract
- The aim of the study is to do a very wide analysis of HA, NA and M influenza gene segments to find short nucleotide regions,which differentiate between strains (i.e. H1, H2, ... e.t.c.), hosts, geographic regions, time when sequence was found and combination of time and region using a simple methodology. Finding regions differentiating between strains has as its goal the construction of a Luminex microarray which will allow quick and efficient strain recognition. Discovery for the other splitting factors could shed lighton structures significant for host specificity and on the history of influenza evolution. A large number of places in the HA, NA and M gene segments were found that can differentiate between hosts, regions, time and combination of time and region. Also very good differentiation between different Hx strains can be seen.We link one of our findings to a proposed stochastic model of creation of viral phylogenetic trees.
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| 2. |
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| 3. |
- Daneva (Mitradjieva), Maria, et al.
(författare)
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A Comparison of Feasible Direction Methods for the Stochastic Transportation Problem
- 2010
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Ingår i: Computational optimization and applications. - : Springer Science and Business Media LLC. - 0926-6003 .- 1573-2894. ; 46:3, s. 451-466
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Tidskriftsartikel (refereegranskat)abstract
- The feasible direction method of Frank and Wolfe has been claimed to be efficient for solving the stochastic transportation problem. While this is true for very moderate accuracy requirements, substantially more efficient algorithms are otherwise diagonalized Newton and conjugate Frank–Wolfe algorithms, which we describe and evaluate. Like the Frank–Wolfe algorithm, these two algorithms take advantage of the structure of the stochastic transportation problem. We also introduce a Frank–Wolfe type algorithm with multi-dimensional search; this search procedure exploits the Cartesian product structure of the problem. Numerical results for two classic test problem sets are given. The three new methods that are considered are shown to be superior to the Frank–Wolfe method, and also to an earlier suggested heuristic acceleration of the Frank–Wolfe method.
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| 4. |
- Fink, Helen, 1978, et al.
(författare)
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Real-time measurements of coagulation on bacterial cellulose and conventional vascular graft materials.
- 2010
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Ingår i: Acta biomaterialia. - : Elsevier BV. - 1878-7568 .- 1742-7061. ; 6:3, s. 1125-30
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Tidskriftsartikel (refereegranskat)abstract
- The search for a functional, small diameter (<5mm) vascular graft has been ongoing for over 30 years, but yet there is no consistently reliable synthetic graft. The primary mechanisms of graft failure are intimal hyperplasia, poor blood flow and surface thrombogenicity. Bacterial cellulose (BC) became therefore a proposed new biosynthetic vascular graft material. Since conventional methods are not suited for coagulation measurements on BC, we have adapted the automated calibrated thrombin generation method for measurements of biomaterial-induced coagulation of BC as compared with clinically used graft materials i.e., expanded poly(tetrafluoroethylene) (ePTFE) and poly(ethyleneterephtalat) (PET). We have also visualized the coagulation propagation at the material surfaces. Thrombin generation experiments revealed dramatic differences between the materials tested. Both ePTFE and BC were found to generate longer lag times and ttpeak values than PET. Most importantly, BC was found to generate the lowest "peak", indicating a slower coagulation process at the surface. These results are also supported by the measurements of factor XIIa generation and analysis of surface coagulation times, which were detected in the following increasing order (mean + or - SD): PET (27 + or - 8 min)
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| 5. |
- Hessler, Martin, et al.
(författare)
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Edge cover and polymatroid flow problems
- 2010
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Ingår i: Electronic Journal of Probability. - : Institute of Mathematical Statistics. - 1083-6489. ; 15, s. 2200-2219
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Tidskriftsartikel (refereegranskat)abstract
- In an n by n complete bipartite graph with independent exponentially distributed edge costs, we ask for the minimum total cost of a set of edges of which each vertex is incident to at least one. This so-called minimum edge cover problem is a relaxation of perfect matching. We show that the large n limit cost of the minimum edge cover is W(1)(2) + 2W(1) approximate to 1.456, where W is the Lambert W-function. In particular this means that the minimum edge cover is essentially cheaper than the minimum perfect matching, whose limit cost is pi(2)/6 approximate to 1.645. We obtain this result through a generalization of the perfect matching problem to a setting where we impose a (poly-)matroid structure on the two vertex-sets of the graph, and ask for an edge set of prescribed size connecting independent sets.
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| 6. |
- Håkansson, Bo, 1953, et al.
(författare)
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A novel bone conduction implant (BCI): engineering aspects and pre-clinical studies.
- 2010
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Ingår i: International journal of audiology. - : Informa UK Limited. - 1499-2027 .- 1708-8186. ; 49:3, s. 203-15
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Tidskriftsartikel (refereegranskat)abstract
- Percutaneous bone anchored hearing aids (BAHA) are today an important rehabilitation alternative for patients suffering from conductive or mixed hearing loss. Despite their success they are associated with drawbacks such as skin infections, accidental or spontaneous loss of the bone implant, and patient refusal for treatment due to stigma. A novel bone conduction implant (BCI) system has been proposed as an alternative to the BAHA system because it leaves the skin intact. Such a BCI system has now been developed and the encapsulated transducer uses a non-screw attachment to a hollow recess of the lateral portion of the temporal bone. The aim of this study is to describe the basic engineering principals and some preclinical results obtained with the new BCI system. Laser Doppler vibrometer measurements on three cadaver heads show that the new BCI system produces 0-10 dB higher maximum output acceleration level at the ipsilateral promontory relative to conventional ear-level BAHA at speech frequencies. At the contralateral promontory the maximum output acceleration level was considerably lower for the BCI than for the BAHA.
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| 7. |
- Rodhe, P., et al.
(författare)
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Modelling of peripheral fluid accumulation after a crystalloid bolus in female volunteers - a mathematical study
- 2010
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Ingår i: Computational and Mathematical Methods in Medicine. - : Taylor and Francis. - 1748-670X .- 1748-6718. ; 11:4, s. 341-351
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To simultaneously model plasma dilution and urinary output in female volunteers. Methods. Ten healthy female non-pregnant volunteers, aged 21-39 years (mean 29), with a bodyweight of 58-67kg (mean 62.5kg) participated. No oral fluid or food was allowed between midnight and completion of the experiment. The protocol included an infusion of acetated Ringer's solution, 25ml/kg over 30min. Blood samples (4ml) were taken every 5min during the first 120min, and thereafter the sampling rate was every 10min until the end of the experiment at 240min. A standard bladder catheter connected to a drip counter to monitor urine excretion continuously was used. The data were analysed by empirical calculations as well as by a mathematical model. Results. Maximum urinary output rate was found to be 19 (13-31) ml/min. The subjects were likely to accumulate three times as much of the infused fluid peripherally as centrally; 1/=2.7 (2.0-5.7). Elimination efficacy, Eeff, was 24 (5-35), and the basal elimination kb was 1.11 (0.28-2.90). The total time delay Ttot of urinary output was estimated as 17 (11-31) min. Conclusion. The experimental results showed a large variability in spite of a homogenous volunteer group. It was possible to compute the infusion amount, plasma dilution and simultaneous urinary output for each consecutive time point and thereby the empirical peripheral fluid accumulation. The variability between individuals may be explained by differences in tissue and hormonal responses to fluid boluses, which needs to be further explored.
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| 8. |
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| 9. |
- Rootzén, Johan, 1978, et al.
(författare)
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Carbon Sequestration Versus Bioenergy: A Case Study From South India Exploring The Relative Land Use Efficiency Of Two Options For Climate Change Mitigation
- 2010
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 34:1, s. 116-123
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Tidskriftsartikel (refereegranskat)abstract
- This case study has been carried out as a comparison between two different land-use strategies for climate change mitigation, with possible application within the Clean Development Mechanisms. The benefits of afforestation for carbon sequestration versus for bioenergy production are compared in the context of development planning to meet increasing domestic and agricultural demand for electricity in Hosahalli village, Karnataka, India. One option is to increase the local biomass based electricity generation, requiring an increased biomass plantation area. This option is compared with fossil based electricity generation where the area is instead used for producing wood for non-energy purposes while also sequestering carbon in the soil and standing biomass. The different options have been assessed using the PRO-COMAPmodel. The ranking of the different options varies depending on the system boundaries and time period. Results indicate that, in the short term (30 years) perspective, the mitigation potential of the long rotation plantation is largest, followed by the short rotation plantation delivering wood for energy. The bioenergy option is however preferred if a long-term view is taken. Short rotation forests delivering wood for short-lived non-energy products have the smallest mitigation potential, unless a large share of the wood products are used for energy purposes (replacing fossil fuels) after having served their initial purpose. If managed in a sustainable manner all of these strategies can contribute to the improvement of the social and environmental situation of the local community.
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| 10. |
- Semchuk, O. Yu., et al.
(författare)
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Thermal effects caused by action of powerful laser radiation on condensed matter
- 2010
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Ingår i: JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS. - : Inoe and Infm. - 1454-4164. ; 12:3, s. 586-588
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Tidskriftsartikel (refereegranskat)abstract
- The spatial and temporal temperature distribution on a solid's surface heated by laser interference pattern is calculated using integral transformation on coordinates x, y and Fourier transformation on coordinate z . Two-dimensional periodic structure consisting of circles with radii equal to a radius of the laser beam is considered. It is shown, that the maximal heating is observed in the center of a circle while diminishing to periphery. The area where the intensive surface heating is observed extends up to 0.8 r/a ( a is a period of the grating, r is a radius of the laser beam).
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