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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Optimizing the Production of Aurora Kinase A and Validation of Constructs with different Sequential Lengths

Pierre, Linnea January 2022 (has links)
Aurora Kinase A is a kinase involved in multiple signaling pathways and interactions during mitosis, making it an essential kinase that deregulated causes cancer diseases in affected patients. Structural research shows mainly static snapshots of possible conformations of the partly disordered protein. This is due to challenges in generating a monodisperse pure sample with high stability enough for dynamic biophysical measurements. Optimizing the production of Aurora A and validating constructs with different sequential lengths using light scattering techniques, thermal stability screening, mass characterization, mass spectrometry, and immunoassay techniques is important for future structural insights useful for drug discoveries. In this project, validation of constructs concluded that no significant difference in cleavage of His-tag, purification possibilities, monodispersity nor stability is shown by variate start residue from 118-122 to end residue 403. Expression of an Aurora Kinase A constructs with sequential length 118-403 is preferred to be executed at 18 degrees, otherwise, temperature differences during expression show no impact on produced Aurora A. Magnesium chloride has been shown to have an impact on stability where a higher concentration stabilizes Aurora Kinase A. Moreover, concentration differences of NaCl were shown to not affect the stability of Aurora A. During this project a polydisperse sample was generated and has given insights into Aurora A´s behavior in solution.
132

Impact of BPA, BPF and Mixture N1 on DNA-Methylation of GRIN2B and NR3C1 during human neuroprogenitor cell differentiation

Richter, Franziska Sophie January 2023 (has links)
Endocrine disrupting chemicals (EDCs) are ubiquitous and their adverse impact on nature, wildlife and humans is extensively researched. We are constantly exposed to EDCs, such as the widespread and extensively researched Bisphenol A, as well as its substitute Bisphenol F, which is coming into wider use, even though it is much less is researched and limited information is available about its endocrine effects. Realistically, we are exposed to mixtures rather than single substances. In the Swedish Environmental Longitudinal, Mother and Child, Asthma and allergy (SELMA) study, the co-exposure of EDCs was assessed. Based on the SELMA cohort data, a study identified a mixture of EDCs, Mixture N1, which is associated with delayed language development. In recent years, it has been hypothesized that epigenetic alterations are one of the underlying mechanisms for the effect of EDC exposures. For example, EDC induced changes in DNA Methylation of the promoter region of a gene might lead to altered gene expression, which can result in adverse health effects. Several studies already indicate an impact of the formerly introduced chemicals/mixtures on the DNA methylation on genes such as NR3C1 and GRIN2B in animals. However, limited research is available on the impact on NR3C1 and GRIN2B in the early human brain, which is of interest since both genes are crucial for the development of the brain and altered gene expression often leads to adverse effects. This study aimed to investigate the impact of BPA, BPF and Mixture N1 on NR3C1 and GRIN2B in the developing human brain as well as establish a protocol for differentiation of human stem cells into neuroprogenitor cells that express GRIN2B and NR3C1. In the end stem cells were differentiated in vitro into neural progenitor cells (NPCs) using the protocol of Hosseini et al. (2020). During the differentiation, the cells were exposed to different concentrations of the former mentioned chemicals. Afterwards, RNA and DNA were extracted, followed by a qPCR and bisulfite-pyrosequencing to investigate the changes in gene expression and DNA methylation of NR3C1 and GRIN2B. This study established the differentiation protocol but revealed no significant results regarding the chemical exposure. However, some chemical exposures showed a clear tendency towards an impact of the chemicals on the gene expression and the DNA methylation. Furthermore, a negative correlation between DNA methylation at 2 CpG sites and gene expression in NR3C1 could be observed. In conclusion, the DNA methylation at promoter region in NR3C1 is important for the gene expression.
133

Blomsterlupin versus tre inhemska ärtväxtarter : Jämförelser av besöksfrekvens och pollineringseffektivitet hos olika grupper av insektspollinatörer / Garden lupin versus three native legume species : Comparisons of visitation frequency and pollination effectivity for different groups of insect pollinators

Westling, Tobias January 2023 (has links)
Red clover (Trifolium pratense) is currently used as a green fertilizer for agriculture in northern Sweden. However, due to its low resistance against diseases and a minimal benefit to local pollinators, there is a need to find alternative native species that maximize the benefits for pollinators and agriculture. Garden lupin (Lupinus polyphyllus), another legume, is an invasive alien species in Sweden that may affect the behavior of pollinators and therefore the pollination success of local plant species. The main aim of this study was to increase the knowledge of the legumes cow vetch (Vicia cracca), garden lupin, marsh pea (Lathyrus palustris) and red clover by observing their insect visitors and potential pollinators. The work was divided into subproject 1 (delprojekt 1) and subproject 2 (delprojekt 2). Delprojekt 1 studied insect visitation frequencies in one plot where garden lupin, cow vetch and red clover grew together in Burträsk, while delprojekt 2 studied insect pollination effectivity in two plots where one plot (Fäbodsanden) contained only marsh pea and the other plot (Skäret) contained both garden lupin and marsh pea. Data were collected via field observations. In ‘delprojekt 1', both bumblebees and solitary bees showed a significantly higher visit frequency to garden lupin than to cow vetch and red clover. In ‘delprojekt 2’, flies showed a significantly higher pollination effectivity on garden lupin than on marsh pea in Skäret. Both flies and bumblebees showed a significantly higher pollination effectivity on marsh pea in Fäbodsanden than in Skäret. This indicate that visitation frequencies to cow vetch and red clover as well as pollination effectivity on marsh pea may be affected by the presence/absence of garden lupin. For future studies, examples on how to extend the knowledge even further on plant-pollinator interactions are suggested.
134

Stödmaterial avsett för undervisning om hållbar utveckling i förskolan : En kvalitativ innehållsanalys av stödmaterial som syftar till att främja barns handlingskompetens / Support materials about sustainable development intended for preschool teaching : A qualitative content analysis of support materials aimed at promoting children’s action competence

Eriksson, Amanda January 2023 (has links)
Teaching can be perceived as a complex concept, as can sustainable development and what these concepts mean for preschool activities. Therefore, support materials for teaching sustainable development are likely to be used by preschool staff. There is evidence that teachers need to know how to teach in order to promote children’s action competence in sustainable development. Against this background, this study aims to analyse such support materials through a qualitative content analysis. The study’s theory is based on the Education for Sustainable Development (ESD) framework and qualifications that characterise teaching that promotes children’s action competence in sustainable development. Collected data consists of parts from three Swedish-language support materials aimed at preschool. The study shows that the support materials generally fulfil the study’s analysis criteria for promoting children’s action competence. These support materials can contribute to the development of knowledge about sustainable development, promote the belief in one’s own competence to change, strengthen courage and commitment and the will to change, and promote responsibility. Furthermore, the support materials are open to different end products and, through their use, enable children to reflect on different ways of acting and reasoning. Differences between the three support materials are that two of them direct opinions towards normalised actions, which according to the study’s theory should not be included in teaching to promote children’s action competence. The support materials vary in the description of the conditions required to use the content in practice, with one of them requiring more subject knowledge from the pedagogue than the others. And one of them contains leading questions rather than open questions. The results show that the three support materials could be used in preschool to promote children’s action competence in sustainable development. The range of available support materials for teaching sustainable development that clearly aim to promote action competence is limited and therefore a challenge may be to find a suitable support material that meets such a purpose. / Undervisning kan uppfattas som ett komplext begrepp, likaså hållbar utveckling och vad dessa begrepp innebär för förskolans verksamhet. Därför kan stödmaterial avsett för undervisning om hållbar utveckling troligen vara något som används av förskolepersonal. Det finns grund för att lärare behöver veta hur de kan undervisa för att främja barns handlingskompetens inom hållbar utveckling. Med detta som bakgrund syftar studien till att analysera sådana stödmaterial genom en kvalitativ innehållsanalys. Studiens teori är utifrån ramverket Utbildning för Hållbar Utveckling (UHU) och kvalifikationer som utmärker undervisning som främjar barns handlingskompetens inom hållbar utveckling. Insamlade data består av delar från tre svenskspråkiga stödmaterial riktade till förskolan. Studien visar att stödmaterialen över lag uppfyller studiens analyskriterier för att främja barns handlingskompetens. Stödmaterialen kan bidra till att utveckla kunskaper om hållbar utveckling, främja tron på egen kompetens att förändra, styrka mod och engagemang för samt viljan att förändra och främja ansvarstagande. Vidare är stödmaterialen öppna för olika slutprodukter och ger genom användandet barn möjlighet att reflektera kring olika sätt att agera och resonera. Skillnader mellan de tre stödmaterialen är att två av dem riktar åsikter mot normerade handlingar, vilket enligt teorin inte ska finnas med i undervisning för att främja barns handlingskompetens. Stödmaterialen varierar i beskrivandet av vilka förutsättningar som krävs för att använda innehållet i praktiken, där bland annat ett av dem kräver mer ämneskunskaper hos pedagogen än de övriga. Och ett av dem innehåller ledande frågor snarare än öppna. Resultatet visar att de tre stödmaterialen skulle kunna användas i förskolan för att främja barns handlingskompetens inom hållbar utveckling. Utbudet av tillgängliga stödmaterial till undervisning om hållbar utveckling som tydligt syftar till att främja handlingskompetens är begränsat och därför kan en utmaning vara att finna ett lämpligt stödmaterial som uppfyller sådant syfte.
135

Behavioral effects of deep brain stimulation in the subthalamic nucleus in obsessive compulsive disorder

Antonsson, Rebecka January 2021 (has links)
Obsessive compulsive disorder (OCD) is one of the most disabling psychiatric disorder. About 10% of patients with OCD do not respond to pharmacological treatment. However, deep brain stimulation (DBS) has advanced as an alternative treatment. In 2002, two patients who suffered from co-morbidity of Parkinson’s disease (PD) and OCD were treated with DBS for their PD, with DBS-electrodes placed in the subthalamic nucleus (STN). Surprisingly, not only PD symptoms but also OCD symptoms were improved. This was the first time that patients with OCD were treated with DBS in STN and it was found to markedly improve their symptoms. When performing DBS in patients with OCD, as well as for treating PD, several side-effectshave been observed. The side-effects can be both physical and psychological. In this project,the aim is to investigate the efficiency and side-effects of DBS in OCD, correlated with the position of the electrode in, or near, the STN. To address the aim, 10 published reports were analysed. It was found that all electrode positions reported resulted in great improvement of OCD symptoms. In fact, 88% of patients had significant improvement. There was no clear correlation between position of the electrode and number or type of side-effect. However, there was a trend that patients with the electrode placed in associative/limbic STN suffered from more side-effects. In conclusion, this project demonstrates that there might be a correlation between target for electrode stimulation and side-effects. It would be interesting analyse this closer, including additional electrode target areas, but also consider other possible explanations for the variety of side-effects caused by DBS for OCD.
136

Potential application areas for Fresenius Kabi's bonus products

Karlsson, Jenny, Brink, Matilda, Annala, Elina January 2019 (has links)
The main purpose of the project was to investigate existing markets within the food- and cosmetic industry in order to determine a strategy for market entrance with the bonus product of Fresenius Kabi. The original bonus product, P080, is a rest product from the process where phospholipids are extracted from egg yolk powder. P80 is a refine version of the P080 where egg yolk oil has been extracted, hence the protein content in P80 is higher. The extracted egg yolk oil is the final portion of the bonus product. Thereby, the original bonus product can be divided into two refined fractions. This project investigates the potential for each of these three substances to be a part of a fictive product.  By scanning the global protein market as well as the egg yolk protein and egg oil market, seven potential product segments were discovered. These segments were further evaluated in order to bring out specific products that were potential candidates as products based on the bonus product.  The analysis resulted in two fictive products based on P080; high value nutrition bars and snacks for seniors, one based on P80; protein powder, and one based on egg yolk oil; dietary supplement. All presented in three business cases.
137

Vasodilatory effects of exogenous nitric oxide on the brood patch of the Zebra finch (Taeniopygia guttata)

Södergren, Anna January 2010 (has links)
In birds like the Zebra finch (Taeniopygia guttata) the female, but not the male develop a brood patch upon incubation of eggs. The brood patch functions to increase heat exchange between the bird and the eggs. Development of the brood patch includes de-feathering, increased vascularization and edema formation. The increased vascularization is due to the development of arteriovenous anastomoses, AVA. The AVA are thermoregulatory vessels involved in cold induced vasodilation, CIVD, demonstrated to occur in the brood patch. Nitric oxide, NO, which is a well known vasodilator is a candidate substance for involvement in CIVD. In this study a NO-generating gel was applied to the brood patch of male and female zebra finches. Vasodilation was found to be markedly larger in females than in males. The larger vasodilation in the female brood patch is probably because NO vasodilate AVA selectively more than any other vessels. The study also investigated whether vasodilation would cause an increase in brood patch temperature. No definite changes in brood patch temperature could be observed and no conclusions could be drawn in the matter.
138

Reproductive physiology of the female three-spined stickleback, Gasterosteus aculeatus

Roufidou, Chrysoula January 2017 (has links)
Reproduction in vertebrates, including fishes, is under control of the brain-pituitary-gonad (BPG) axis. The female three-spined stickleback, Gasterosteus aculeatus, produces egg clutches at intervals of a few days and spawns them in a nest built by male. Following ovulation, eggs are stored in the ovarian cavity surrounded by the ovarian fluid (OF). If spawning or spontaneous release do not occur, the eggs can undergo overripening, a phenomenon occurring both in nature and captivity. In this PhD thesis, the changes of reproductive hormones and vitellogenesis were studied at overripening of eggs and over the natural spawning cycle. OF properties were also examined at overripening of eggs and after treatment with sex steroids. Plasma levels of steroids: testosterone (T), estradiol (E2), 17,20β-dihydroxypregn-4-en-3-one (17,20β-P) and 17,20β,21-trihydroxypregn-4-en-3-one (17,20β,21-P) were measured by radioimmunoassay, and relative mRNA levels of the pituitary gonadotropins (fsh-β/lh-β), brain gonadotropin-releasing hormones (gnrh2/gnrh3) and kisspeptin and its receptor (kiss2/gpr54) by qPCR. Overripening of eggs was accompanied with a significant reduction in most of endocrine parameters of BPG axis (T, E2, 17,20β-P; lh-β; kiss2, gpr54). Low level of hormones could be advantageous for the overripe egg-bound females, since this would reduce further ovulations giving higher chances to survive and reproduce again. Over the 3-day spawning cycle, T and E2 were highly correlated, showed cyclicity with low levels at ovulation and increasing from 24 and 6 hours post-spawning (hps), respectively. Spawning may give rise to this increase as these rises did not occur if release of the eggs does not happen (overripe females). A peak at pituitary lh-β mRNA levels appeared 48 hps, a day before the next ovulation. No significant changes were found for the other studied hormones. Vitellogenesis was studied by measurement of the vitellogenin mRNA levels in the liver by qPCR. The levels were highest at 24 and 48 hps and were positively correlated to both E2 and T over the cycle. However, changes were small suggesting a rather continuous vitellogenesis over the stickleback spawning cycle which could be an advantage for a multiple spawner with a limited spawning season. Overripening reduced vitellogenin mRNA levels but did not abolish it. OF amount was diminished in overripe females and had a lower viscocity but higher dry weight and protein levels than in non-overripe ovulated females, suggesting that changes in OF properties are related to the egg overripening. The effects of steroids were studied using Silastic capsules. T and 17,20β-P induced an increase of OF amount, but protein levels were only increased in 17,20β-P-treated females, proposing a role of this steroid in the control of OF secretion. 1-D SDS-PAGE showed that OF contained several proteins, some of them came from eggs, but no consistent differences between groups. Concluding, the knowledge of the reproductive physiological changes is important for understanding their essential roles in the production of viable eggs in this species but also in the reproductive physiology of female fishes in general. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>
139

Fungerar AHA-metoden för epifytiska lavar och mossor? : En studie av naturvärdesindikatorer hos träd i park- och kyrkliga kulturmiljöer / Does the AHA method work for epiphytic lichens and mosses? : A study of nature value indicators of trees in park and church cultural environments

Alkufai, Meysah January 2021 (has links)
Gamla träd i kulturmiljöer uppmärksammas alltmer inom naturvården på grund av sina höga naturvärden och är viktiga som värdar för fortlevnaden av hotade och sällsynta växt- och djurarter. Studiens syfte var att undersöka om Sörenssons AHA-metod (framtagen för vedlevande insekter) fungerar också på mossor och lavar, samt att jämföra två kulturmiljöer med gamla träd. Inventeringen utfördes i Kristianstad och omfattade totalt 443 träd; 230 i Tivoliparken och 213 på Östra begravningsplatsen. Träden bedömdes utifrån olika karaktärer: förekomst av håligheter, barklösa partier, grenhål, savflöde samt svamppåväxt. Förekomsten av dessa användes sedan för att dela in träden i fem olika klasser av varierande värde för naturvården. Även kryptogamer inventerades; dels förutbestämda lavar och mossor som signalerar höga naturvärden, dels en enkel bedömning av det totala antalet triviala arter på varje träd. Träden i Tivoliparken hade större spridning mellan AHA-klasserna. Här hamnade 56 träd i de högsta värdeklasserna (klass I och II-träd), 114 i värdeklass III och 60 som resursträd. På Östra begravningsplatsen hamnade hälften av träden i de högsta värdeklasserna och 93 i värdeklass III. De resterade träden klassades som resursträd. Totalt gjordes 89fynd av 6 signalarter på de inventerade träden, samt en vedsvamp. Dessa fynd gjordes både på träd med höga och låga värden enligt AHA-metoden. AHA-klasser med högre naturvärde hade lägre artrikedom för samtliga träd sammanslagna, men inget samband för enbart trädslagen bok och lind. Endast hälften av träden med signalarter fick hög AHA-klassning. Resultatet antyder att AHA-metoden inte fungerar på kryptogamer som den gör för vedlevande insekter. / Old trees in cultural environments are receiving increasing attention in nature conservation due to their high conservation values and provide important habitat for endangered plant and animal species. The purposes of the study were to investigate whether Sörensson's AHA-method is applicable also to mosses and lichens, as well as to compare two environments with old trees. 443 trees were inventoried in Kristianstad, of which 230 in Tivoliparken and 213 in Östra begravningsplatsen. The trees were assessed based on the occurrence of: cavities, barkless areas, and so on. These findings were used to assign each tree to the five AHA classes of varying conservation value. Trees were also searched for predetermined lichens and mosses signalling high conservation value, and a simple count was made of the total number of trivial cryptogam species on each tree. Tivoliparken had a wider scatter of trees among the AHA classes; 56 in the highest value classes (class I and II), 114 in class III, and 60 as resource trees. At Östra begravningsplatsen, half of the oldest trees were in the two highest value classes and 93 in class III. The remaining trees ended up as resource trees. In total, 89 records of 6 signal species were made, and one wood fungus. There was a significant association between AHA class and richness of trivial species when trees of all species were pooled, but no association when beech and linden were assessed separately. These results suggest that the AHA method does not work on cryptogams.
140

Development, Modelling and Investigation of a Robotic Exoskeleton for Astronaut Back Support

Häggman, Evert January 2021 (has links)
Musculoskeletal disorders, specifically low back pain, has been well documented andreported by astronauts throughout the space exploration era. Statistics from astronautmemoirs states that 52-68% of astronauts experience moderate to severe lower backpain after prolonged spaceflights. The main cause is atrophy in the paraspinal musclesof the lumbar region. No sufficient countermeasure exists in-flight currently and therehabilitation programs remain ineffective. This thesis presents the first attempt to designand develop a prototype robotic exoskeleton, actuated by pneumatic artificial muscles, asan active countermeasure in-flight where it will be utilised as an equipment for muscularhypertrophy and a supporting device for rehabilitation programs on Earth. It will bemanufactured by additive manufacturing methods for adaptability while remaining lowin weight.A thorough analysis of the spine and lumbar region as a biomechanical system wasmade. Appropriate assumptions was made to simplify the understanding of the complexsystem that is the human spine. The targeted muscles were: multifidus, erector spinaeiliocostalis and erector spinae longissimus. A force analysis of the human torso bendingin the sagittal plane was made, finding that the torques of the torso reaches 244 Nm.The complete exoskeleton design is presented with the parts that will be 3D-printed andthe working principle of the system. Thereafter an extensive model of the exoskeletonis established using Denavit-Hartenberg representation of manipulators as a serial linksystem. The model provides a fundamental understanding of exoskeleton and enablesthe possibility to simulate it accurately. The evaluation protocol for the validation testsis then presented. Active pressure will be tested at 0, 3 and 6 bar and loads of 5 and 11kg will be lifted.Subsequently the assembly, with all the hardware and software selected for the prototypeis demonstrated. Thereafter the results of the evaluation tests are presented followed bya discussion of the results; anomalies, faults and challenges are subjects discussed. Thediscussion concludes that the exoskeleton shows potential for both supporting the motionin a rehabilitation use and enabling muscular hypertrophy in the lumbar region for theresistive tests. Although an extensive heavy-duty evaluation needs to be performed totruly validate the exoskeleton.

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