| 1. |
- Aamodt, A., et al.
(författare)
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Case-based reasoning for assessment and diagnosis of depression in palliative care
- 2010
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Ingår i: Proceedings - IEEE Symposium on Computer-Based Medical Systems. ; , s. 480-485
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Konferensbidrag (refereegranskat)abstract
- The goal of the research presented is to create a computational framework and system architecture for clinical decision support in palliative care. The application focused is the classification of depression. The method under investigation is case-based reasoning, motivated by the complexity of the domain and a lack of generalized principles of sufficient coverage and strength for diagnosis and treatment. A system architecture is described and exemplified through an implemented prototype. The outcome of the research so far is a system that captures the properties intended, and for which a clinical test set-up has been defined. © 2010 IEEE.
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| 2. |
- Abdelhady, Wael Awad
(författare)
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Glypican-1: Structural and functional analysis of the N-glycosylated human protein
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Glypicans are multifunctional cell surface heparan sulphate proteoglycans co-regulating numerous signalling pathways, and are thereby involved in the control of cellular division, differentiation, and morphogenesis. The heparan sulphate (HS) chains are responsible for many of those biological functions; nevertheless recent studies suggest functional roles for the glypican core proteins in mediating the signalling of various growth factors. Glypican-1 (GPC1) is the predominant HS proteoglycan in the developing and adult human brain. In addition, GPC1 is involved in Alzheimer’s disease and scrapie, among others. There is a shortage of detailed structural knowledge regarding the GPC1 core protein and accordingly, we proposed in this thesis to structurally and functionally characterize the human GPC1 core protein and to elucidate its overall topology with respect to the membrane. First, we determined the crystal structure of the human N-glycosylated GPC1 core protein by the two-wavelength MAD method on a SeMet-substituted protein crystal. The GPC1 structure revealed a quite rigid, cylindrical single-domain all α-helical fold with three substantial loops. Shortly afterwards, we achieved improvements of GPC1 crystal diffraction properties by controlled crystal dehydration using a humidity control device (HC1b) and generated better electron density for crystals of GPC1, allowing the building of previously disordered parts of the structure. Using small angle X-ray scattering and other biophysical approaches, we found that the GPC1 core protein lies on the membrane in a transverse orientation, directing a surface evolutionarily conserved in GPC1 orthologues towards the membrane, where it can interact with enzymes involved in HS substitution in the Golgi apparatus. Furthermore, the N-linked glycans are shown to extend the protein stability and lifetime by protection against proteolysis and aggregation. The EXTL3 protein, a member of the exostosin family, functions mainly as an initiator for HS assembly on the glypicans. We have investigated the spectroscopic and structural characteristics of the catalytic region of EXTL3, which exhibits a quite stable extended monomeric structure with two functional domains containing a majority of β sheets. Additionally, it was found that catalytic EXTL3 is occupied with N-glycans at least at two sites and these N-glycans seem critical for proper EXTL3 biosynthesis. To precisely determine how the GPC1 core protein regulates HS assembly through interactions with EXTL3, investigations of the GPC1-EXTL3 complexes are ongoing, and some preliminary results are presented here.
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| 3. |
- Abdullah, Gamil M. S., et al.
(författare)
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Boosting-based ensemble machine learning models for predicting unconfined compressive strength of geopolymer stabilized clayey soil
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The present research employs new boosting-based ensemble machine learning models i.e., gradient boosting (GB) and adaptive boosting (AdaBoost) to predict the unconfined compressive strength (UCS) of geopolymer stabilized clayey soil. The GB and AdaBoost models were developed and validated using 270 clayey soil samples stabilized with geopolymer, with ground-granulated blast-furnace slag and fly ash as source materials and sodium hydroxide solution as alkali activator. The database was randomly divided into training (80%) and testing (20%) sets for model development and validation. Several performance metrics, including coefficient of determination (R2), mean absolute error (MAE), root mean square error (RMSE), and mean squared error (MSE), were utilized to assess the accuracy and reliability of the developed models. The statistical results of this research showed that the GB and AdaBoost are reliable models based on the obtained values of R2 (= 0.980, 0.975), MAE (= 0.585, 0.655), RMSE (= 0.969, 1.088), and MSE (= 0.940, 1.185) for the testing dataset, respectively compared to the widely used artificial neural network, random forest, extreme gradient boosting, multivariable regression, and multi-gen genetic programming based models. Furthermore, the sensitivity analysis result shows that ground-granulated blast-furnace slag content was the key parameter affecting the UCS.
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| 4. |
- Abramson, Nils
(författare)
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Holography, relativity and the spooky ellipsoids
- 2006
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Ingår i: Proceedings of the 7th International Symposium on Display Holography. ; , s. 228-235
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Konferensbidrag (refereegranskat)abstract
- The further away from a house we move, the smaller it appears. We could say that we are in the centre of a "sphere of observation", which must reach the house before we can see it. The larger that sphere is, the smaller the house appears. This is natural to us and not difficult to understand. In Einstein's Special Relativity it is stated that the faster we move past a house, the shorter it appears. We state in this paper that this is because the faster we travel, the more our "sphere of observation" is elongated into an "ellipsoid of observation". The longer that ellipsoid is, the shorter the house appears. This contraction is not so natural to us, because to be observable the velocity has to be extremely high, almost close to the velocity of light. A similar phenomenon can, however, be studied when holography with ultrashort pulses is used for measurement. In this case the sphere of observation is also transformed into an ellipsoid of observation. Thus, according to our approach objects appear shorter because the definition of length (the metre) becomes longer, just as time moves slower because the definition of time (the second) becomes longer. The transformation of the sphere into an ellipsoid is however hidden to the observer both in the case of holography and in relativity. This spooky behaviour of the ellipsoid has resulted in a new mathematical theorem.
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| 5. |
- Abramson, N, et al.
(författare)
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Light-in-flight recording. 5: Theory of slowing down the faster-than-light motion of the light shutter
- 1989
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Ingår i: Applied Optics. - 2155-3165. ; 28:4, s. 759-765
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Tidskriftsartikel (refereegranskat)abstract
- Light-in-flight recording by holography uses a picosecond pulse for the reference beam, which like a sheet of light intersects the hologram plate and produces a sensitivity area that with a speed faster than light moves over the plate like a light shutter. If, however, the front of the reference pulse by diffraction in a grating is tilted relative to its direction of motion, the velocity of the light shutter can be slowed down resulting in increased recording time. The practical result using a reflection grating was a true recording that corresponded to a time compression of two to one. To minimize distortions of the recorded pulse shape we studied intersections that are identical for apparent (ellipsoidal) and true (spheroidal) wavefronts.
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| 6. |
- Abu-Raya, Bahaa, et al.
(författare)
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Antibody and B-cell Immune Responses Against Bordetella Pertussis Following Infection and Immunization
- 2023
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Ingår i: Journal of Molecular Biology. - 0022-2836 .- 1089-8638. ; 435:24
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Forskningsöversikt (refereegranskat)abstract
- Neither immunization nor recovery from natural infection provides life-long protection against Bordetella pertussis. Replacement of a whole-cell pertussis (wP) vaccine with an acellular pertussis (aP) vaccine, mutations in B. pertussis strains, and better diagnostic techniques, contribute to resurgence of number of cases especially in young infants. Development of new immunization strategies relies on a comprehensive understanding of immune system responses to infection and immunization and how triggering these immune components would ensure protective immunity. In this review, we assess how B cells, and their secretory products, antibodies, respond to B. pertussis infection, current and novel vaccines and highlight similarities and differences in these responses. We first focus on antibody-mediated immunity. We discuss antibody (sub)classes, elaborate on antibody avidity, ability to neutralize pertussis toxin, and summarize different effector functions, i.e. ability to activate complement, promote phagocytosis and activate NK cells. We then discuss challenges and opportunities in studying B-cell immunity. We highlight shared and unique aspects of B-cell and plasma cell responses to infection and immunization, and discuss how responses to novel immunization strategies better resemble those triggered by a natural infection (i.e., by triggering responses in mucosa and production of IgA). With this comprehensive review, we aim to shed some new light on the role of B cells and antibodies in the pertussis immunity to guide new vaccine development.
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| 7. |
- Agholme, Fredrik, et al.
(författare)
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Local bisphosphonate release versus hydroxyapatite coating for stainless steel screw fixation in rat tibiae
- 2012
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Verlag (Germany). - 0957-4530 .- 1573-4838. ; 23:3, s. 743-752
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Tidskriftsartikel (refereegranskat)abstract
- Implant fixation in bone can be improved by a coating that delivers bisphosphonates locally, or by a hydroxyapatite (HA) coating. In this study, we compared these different types of coatings. For mechanical testing, 30 rats were assigned into three groups, and similar screws were implanted bilaterally in the proximal tibiae. The rats received screws that were either uncoated, coated with nano-crystalline hydroxyapatite or coated with a bisphosphonate releasing protein matrix. After 4 weeks, one screw was subjected to pull-out testing, and the contra-lateral one to torsion testing. For morphology, 30 rats were assigned to similar treatment groups, but received only one screw each. Bisphosphonates enhanced the pull-out force by 41% (P = 0.02) compared to controls, HA increased the pull-out force although not significantly. Conversely, HA increased the maximal torque by 64% (P = 0.02). Morphometry showed higher bone volume around bisphosphonate screws in comparison to HA-coated screws (P andlt; 0.001) and controls (P andlt; 0.001). The results suggest that bisphosphonates improve fixation by increasing the amount of surrounding bone, whereas HA mainly improves bone to implant attachment.
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| 8. |
- Akin, Danny E., et al.
(författare)
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Progress in enzyme-retting of flax
- 2004
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Ingår i: Journal of Natural Fibers. - 1544-0478. ; 1:1, s. 21-47
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Tidskriftsartikel (refereegranskat)abstract
- New methods for retting flax are sought to overcome problems in the current method of dew-retting of flax. Published data are reviewed and new data presented on the development and testing of a method to ret flax using pectinase-rich enzyme mixtures plus chelators based on cost and fiber yield and properties. In spray enzyme retting (SER), flax stems are crimped to physically disrupt the plant's protective barrier and then sprayed until soaked with, or briefly immersed in, an enzyme/ chelator formulation. Flax is then incubated at temperatures optimal for enzyme activity, washed, and dried. Pilot scale tests, conducted with 10 kg samples of flax retted with a series of formulations, showed that this method effectively retted flax stems from a variety of sources, including fiber flax, mature fiber flax, and linseed straw. Fiber yield, strength, and fineness were significantly influenced by variations in enzyme-chelator amounts. Cellulases in pectinase mixtures appeared to preferentially attack dislocations in fibers and fiber bundles resulting in loss of fiber strength. Polygalacturonases alone effectively separated fiber from non-fiber components. The SER method proved to be an effective framework for further tests on enzyme-chelator formulations that now must be integrated with physical processing to optimize the extraction of flax fibers based on cost and fiber yield and properties.
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| 9. |
- Aksimsek, Sinan, et al.
(författare)
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TEM wave scattering by a step discontinuity on the outer wall of a coaxial waveguide
- 2013
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Ingår i: IEEE transactions on microwave theory and techniques. - : IEEE Press. - 0018-9480 .- 1557-9670. ; 61:8, s. 2783-2791
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the propagation of TEM waves along a coaxial waveguide with a step discontinuity on its outer wall is investigated rigorously by applying the direct Fourier transform and reducing the problem into the solution of a modified Wiener–Hopf equation. The solution for the field terms are determined in terms of an infinite number of unknown coefficients, which satisfy an infinite set of linear algebraic equations. These equations are solved numerically and the effect of area ratio is presented graphically at the end of the analysis. The same problem is also analyzed by applying the mode-matching technique and the results of the two approaches are compared. It is observed numerically that the Wiener–Hopf technique provides a better convergence than the mode-matching technique.
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| 10. |
- Alavioon, Ghazal, 1986-, et al.
(författare)
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The fitness consequences of selection among sperm within an ejaculate across generations
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The evolution of a biphasic life cycle with alternating diploid and haploid phases is a necessary consequence of sexual reproduction in eukaryotes. Selection in each of the phases may have far reaching consequences for many evolutionary processes. While our focus in evolutionary biology lies mainly on selection during the diploid phase, we know relatively little about the role and consequences of selection occurring during the haploid gametic stage. This is particularly true in predominantly diploid animals where the haploid gametic phase is very short. To test the importance of haploid selection in animals, we performed a large-scale selection experiment with selection acting on haploid sperm. We selected on sperm longevity within an ejaculate and tested the effects of such selection over three generation. We performed fitness assays for every generation and found that offspring sired by longer-lived sperm generally exhibit higher fitness from early development into adulthood compared to offspring sired by their shorter-lived sibling sperm in all three generations. These fitness effects were carried over into the second generation without further selection in all three generations. Moreover, using RNA sequencing, we assessed differences in tissue specific gene expression between the offspring sired by the two sperm phenotypes in generation F1 and F3. The transcriptomes in both tissues differed significantly between the two treatments. Many very basic housekeeping genes involved in metabolism and development showed small differences in expression in both tissues. Our study provides solid evidence for the far-reaching consequences of selection on different sperm within a single ejaculate in three consecutive generations, and offers exciting new insights into the possible underlying mechanisms. Our results further highlight the importance of selection at the haploid gametic stages for fundamental evolutionary processes and assisted fertilization technologies.
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