609 research outputs found

    The pore geometry of pharmaceutical coatings: statistical modelling, characterization methods and transport prediction

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    This thesis contains new methods for bridging the gap between the pore geometry of porous materials and experimentally measured functional properties. The focus has been on diffusive transport in pharmaceutical coatings used in controlled drug delivery systems, but the methods are general and can be applied to other porous materials and functional properties. Relatively large datasets are needed to train realistic models connecting the pore geometry and diffusive transport properties of porous materials. 3-D statistical pore models based on microscopy images of the coating material were in this thesis used to generate large sets of pore structures, in which diffusive transport was computed numerically. Characterization measures capturing important features of the pore geometry were developed and used as predictors of diffusive transport rates in multiplicative regression models. The characterization measures have been implemented in a freely available software, MIST.In Paper I, a Gaussian random field based pore model was developed and fitted to microscopy images of the coating material. Due to the large size of the data, the model was formulated using a Gaussian Markov random field approximation, which allows for efficient inference. A new method for solving linear equations with Kronecker matrices which reduced the complexity of the model fitting algorithm considerably was developed. The pore model was found to fit the microscopy images well. In Paper II, characterization measures that have been shown to provide good regression models for diffusive transport rates were developed further and implemented. Multiplicative regression models were fitted to pore structures from the model from Paper I, and the new methods were shown to give improved results. In Papers III and V characterization measures that capture a type of bottleneck effect which was observed in another set of microscopy images of the coating material (Papers III and IV), but which is not captured by existing methods, were invented. Pore structures with this type of bottleneck were generated using 3-D statistical pore models, and the new type of bottleneck was found to be an important determinant of diffusive transport rates when the regression models were fitted to simple pore structures (Paper V)

    Lifestyle\u27s influence on community-dwelling older adults\u27 health: A mixed-methods study design

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    Background: Aging often involves health problems and difficulties, such as physical and psychological impairments, isolation, and loneliness, causing social and existential consequences. Studies have explored aging from different perspectives. However, few studies have examined healthy older adults’ genetic backgrounds, lifestyles, and meaning in life separately or in combination. This study aims to describe how healthy older adults experience aging, health, lifestyles, and meaning in life and explore potential genetic correlations. Methods and Design:The project will comprise three main parts: a quantitative section featuring the development and testing of a lifestyle questionnaire, a quantitative genetic analysis, and a qualitative interview study. Participants will be community-dwelling, healthy, older adults between 70 and 95 years of age. A sample size of 800 older adults will be invited to participate in seminars in collaboration with the national Swedish association Active Seniors. Data will be collected through lifestyle questionnaire, DNA extracted from saliva samples, and interviews. Based on questionnaire responses, profile groups will be created and compared statistically with variations in genetic backgrounds, providing the basis for recruiting participants to the qualitative interviews. Discussion: This study’s expected outcome will be to gain knowledge about variations in genetic backgrounds correlated with individual experiences regarding aging, health, and meaning in life. This knowledge can improve the understanding of motivations for healthy lifestyle changes. The results can reveal potential implications for individual prerequisites to healthy aging and how health-promoting aging and lifestyle counseling can be adjusted to meet individual needs

    An Empirical Analysis of Barriers to Building Information Modelling (BIM) Implementation in Wood Construction Projects: Evidence from the Swedish Context

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    Building information modelling is gradually being recognised by the architecture, engineering, construction, and operation industry as a valuable opportunity to increase the efficiency of the built environment. Focusing on the wood construction industry, BIM is becoming a necessity; this is due to its high level of prefabrication and complex digital procedures using wood sawing machines and sophisticated cuttings. However, the full implementation of BIM is still far from reality. The main objective of this paper is to explore the barriers affecting BIM implementation in the Swedish construction industry. An extensive literature review was conducted to extract barriers hindering the implementation of BIM in the construction industry. Secondly, barriers to the implementation of BIM in the wood construction industry in Sweden were extracted using the grounded theory methodology to analyse expert input on the phenomenon of low BIM implementation in the wood construction industry in Sweden. Thirty-four barriers were identified. The analysis of this study also led to the development of a conceptual model that recommended solutions to overcome the barriers identified to help maximise BIM implementation within the wood construction industry. Identifying the main barriers affecting BIM implementation is essential to guide organisational decisions and drive policy, particularly for governments that are considering articulating regulations to expand BIM implementation

    Consequences of specialized breeding in the Swedish Warmblood horse population

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    In many European warmblood studbooks, clear specialization toward either jumping or dressage horses is evident. The Swedish Warmblood (SWB) is also undergoing such specialization, creating a possible need for separate breeding programs and a discipline-specific Young Horse Test (YHT). This study investigated how far specialization of the SWB breed has proceeded and the potential consequences. Individuals in a population of 122,054 SWB horses born between 1980 and 2020 were categorized according to pedigree as jumping (J), dressage (D), allround (AR), or thoroughbred (Th). Data on 8,713 J horses and 6,477 D horses assessed for eight traits in YHT 1999-2020 were used to estimate genetic parameters within and between J and D horses and between different periods. Future scenarios in which young horses are assessed for either jumping or dressage traits at YHT were also analyzed. More than 80% of horses born in 1980-1985 were found to be AR horses, while 92% of horses born in 2016-2020 belonged to a specialized category. The average relationship within J or D category was found to increase during the past decade, whereas the relationship between these categories decreased. Heritability estimates for gait traits were 0.42-0.56 for D horses and 0.25-0.38 for J horses. For jumping traits, heritability estimates were 0.17-0.26 for J horses and 0.10-0.18 for D horses. Genetic correlations between corresponding traits assessed in J and D horses were within the range 0.48-0.81, with a tendency to be lower in the late study period. In the future scenarios, heritability and genetic variance both decreased for traits that were not assessed in all horses, indicating that estimation of breeding value and genetic progress for these traits could be affected by a specialized YHT. However, ranking of sires based on estimated breeding values (EBVs) and accuracy of EBVs was only slightly altered for discipline-specific traits. With continued specialization in SWB, specialization of the YHT should thus be considered

    Föräldrars behov och önskemål av föräldrastöd : en enkätundersökning i Landskrona kommun

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    The aim of the work was to gather information on parents' reflections on their own need for parental support in their role as parents. Where a need was expressed we investigated what form of support was desired and who should provided it. We also wished to find out if there were any differences or similarities in the needs and wishes expressed by the parents. The questions posed were: Did the parents feel that they needed support in their roles as parents? If so, what sort of support did they want? Who should provide this support? What differences or similarities were expressed in the parents needs and wishes for support? A questionnaire study was carried out within Landskrona. The results showed that a majority of parents expressed a limited need for some form of support in their parental role. First and foremost, the parents expressed a wish for informal support from friends and family and also from nursery or primary schools. The parents who declared that they had no need of support nevertheless often still expressed a wish for some form of support and, in fact, often had themselves experience of such support

    Experimental Verification of a Simulation Model for Partial Demagnetization of Permanent Magnets

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    Mechanical Torque Ripple From a Passive Diode Rectifier in a 12 kW Vertical Axis Wind Turbine

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    Performance of a 70-mer oligonucleotide microarray for genotyping of Campylobacter jejuni

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    <p>Abstract</p> <p>Background</p> <p><it>Campylobacter jejuni </it>is widespread in the environment and is the major cause of bacterial gastroenteritis in humans. In the present study we use microarray-based comparative genomic hybridizations (CGH), pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) to analyze closely related <it>C. jejuni </it>isolates from chicken and human infection.</p> <p>Results</p> <p>With the exception of one isolate, the microarray data clusters the isolates according to the five groups determined by PFGE. In contrast, MLST defines only three genotypes among the isolates, indicating a lower resolution. All methods show that there is no inherit difference between isolates infecting humans and chicken, suggesting a common underlying population of <it>C. jejuni</it>. We further identify regions that frequently differ between isolates, including both previously described and novel regions. Finally, we show that genes that belong to certain functional groups differ between isolates more often than expected by chance.</p> <p>Conclusion</p> <p>In this study we demonstrated the utility of 70-mer oligonucleotide microarrays for genotyping of <it>Campylobacter jejuni </it>isolates, with resolution outperforming MLST.</p

    New characterization measures of pore shape and connectivity applied to coatings used for controlled drug release

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    Pore geometry characterization-methods are important tools for understanding how pore structure influences properties such as transport through a porous material. Bottlenecks can have a large influence on transport and related properties. However, existing methods only catch certain types of bottleneck effects caused by variations in pore size. We here introduce a new measure, geodesic channel strength, which captures a different type of bottleneck effect caused by many paths coinciding in the same pore. We further develop new variants of pore size measures and propose a new way of visualizing 3-D characterization results using layered images. The new measures together with existing measures were used to characterize and visualize properties of 3-D FIB-SEM images of three leached ethyl-cellulose/hydroxypropyl-cellulose films. All films were shown to be anisotropic, and the strongest anisotropy was found in the film with lowest porosity. This film had very tortuous paths and strong geodesic channel-bottlenecks, while the paths through the other two films were relatively straight with well-connected pore networks. The geodesic channel strength was shown to give important new visual and quantitative insights about connectivity, and the new pore size measures provided useful information about anisotropies and inhomogeneities in the pore structures. The methods have been implemented in the freely available software MIST
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