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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.
441

Somatiska embryogenes-plantors överlevnad och höjdtillväxt vid fyra ljusförhållanden / Survival and height growth of somatic embryogenesis-seedlings in four different light conditions

Wetterskog, Robert January 2018 (has links)
Somatiska embryogenes är en mikroförökningsmetod som med hjälp av tillväxtreglerande medel får en växtdel att bilda skott och rötter i ett speciellt odlingssubstrat sterila förhållanden. Kunskapen vad gäller förutsättningar för groning och plantetablering efter detta laboratoriestudium är dock begränsad. I denna studie undersökte hur två kloner av SE-groddar av gran etablerade sig i olika ljusförhållanden avseende våglängd och intensitet i fyra växtmiljöer. Etableringen bedömdes utifrån plantornas överlevnad och höjdtillväxt. Vid sista inventeringstillfället var 62 SE-plantor vid liv och 18 plantor var döda. Ingen signifikant skillnad kunde påvisas i överlevnad mellan de olika växtmiljöerna, inte heller mellan klonerna i respektive miljö eller oberoende av miljö. Signifikant skillnad i höjdtillväxten mellan klonerna kunde påvisas inom alla växtmiljöer, men inte mellan växtmiljöerna oberoende av klon. Det fanns en tendens att ljusförhållanden med en ljusintensitet på 100 μmol och rött ljus inom våglängderna 610-760 nm gav bäst etablering för SE-groddarna. Studien visade också att det var skillnad i etablering mellan de två kloner som användes.
442

Anhörigas upplevelser av omvårdnaden av närstående i särskilt boende i Västra Götaland år 2010 / Relatives experience of nursingcare dependent in nursing home in western Sweden in 2010

Andersson, Christian, Pesonen, John January 2010 (has links)
Inledning: När en äldre människa har ett stort omvårdnadsbehov finns möjligheten att flytta till ett särskilt boende. Då äldres vardag ser olika ut är det av yttersta vikt att omvårdnadspersonalen kan ge stöd och hjälp så att den äldre skall kunna anpassa sig till den nya situationen. Syfte: Syftet med denna studie är att belysa hur anhöriga upplever att deras närstående i särskilt boende får en god omvårdnad. Metod: En kvalitativ ansats med empiriskt inslag användes där anhörigas upplevelser av omvårdnad, delaktighet och bemötande insamlades med hjälp av intervjuer. Resultat: Tre olika kategorier Omvårdnad, Delaktighet och Bemötande med nio underkategorier. En betydelsefull del i omvårdnaden är att det skapas en god kontakt mellan anhöriga och omvårdnadspersonalen för att finna ett bra sätt att kommunicera på. Det framkom hur viktigt det är att som vårdtagare känna att de blir sedda för den de är och att de får vara delaktiga i de omvårdnadsåtgärder som beslutas av omvårdnadspersonalen. Diskussion: Resultatet kan bidra till en ökad förståelse för anhörigas upplevelser av hur omvårdnaden bedrivs i särskilt boende. När anhöriga göras mer delaktiga i omvårdnaden, kan det leda till en bättre omvårdnad för vårdtagaren i särskilt boende. Slutsats: Resultatet som författarna kom fram till skulle kunna användas i utbildningssyfte då omsorgen av äldre människor kräver att omvårdnadspersonalen ständigt förnyar sina kunskaper. Detta kan vara till gagn för sjuksköterskan, de anhöriga och de äldre som bor i särskilt boende. / Introduction: When a senior person has a large need for special care there is an option to relocate to a nursing home. The seniors every day varies there for it is of outmost importance the nursing care staff can support the senior that he maybe adapt to the new situation. Purpose: The purpose with this study is to enlighten how relatives experience their close ones in special nursing home receive good care treatment. Method: A quality approach with empirical elements is used where relatives experiences of care, being part of and recievment was collected with the help of interviews. Results: Three categories Care, Involvment and Recievment with nine sub categories. An important part in care is to create good contact between relatives and nursing care staff to evolve good ways for communication. It was revealed how important it is as a health care patient to feel they’re being looked upon for who they are and they be part of treatment measures and decisions made by nursing care staff. Discussion: The results can contribute to an increased understanding to how relatives experience care is being conducted in a special accommodation. When relatives are made more involved in care, may lead to a better care for care patient in a nursing home. Conclusion: The results which have been concluded could be used in educational purposes when the care of senior people demands that nursing care staff continuously renews their knowledges. This could be of use for the nurse, the relatives and the seniors living in a nursing home.
443

Immunoglobulin VH gen analys in human B-cell

Heidari, Ramesh January 2006 (has links)
Malt lymphoma is a malignant disease that can arise in a variety of extra nodal sites. Previous studies indicate that tumour arise from more mature B-cells. Our purpose was to examine the presence of clonality and somatic hypermutation of immunoglobulin (IgVн) of MALT lymphomas. Paraffin-embedded tumour samples from13 MALT lymphoma were subjected to rearrangement analysis, by using PCR, heteroduplex gels and sequence analysis. Successful amplification was seen in 10/13 cases and sequences of IgVн genes were obtained in 6/13, all of them were mutated. The percentage of mutation compared to germline sequences was 1,1% to 8,6% monoclonal rearrangemang. It was demonstrated that 5 of 7 clones were derived from the Vн3 family, 2 from Vн1 and 1 from the Vн 4 family.
444

Differences in nutrient content between varieties of Nordic barley

Norberg, Amanda January 2017 (has links)
Grain protein content (GPC) in wheat has been found to be regulated by the gene NAM-B1. Homologues to the NAM-B1 gene have been found in barley, HvNAM-1 and HvNAM-2. Previous studies have found that base mutations in the NAM-1 gene at base position 544 might have an impact on GPC. Previous studies also found that landrace of barley showed higher GPC than cultivated barley, indicating that plant improvement might have affected base mutations and therefore GPC. I wanted to study if there are any nutritional differences in Nordic barley and if those differences might correlate with haplotypes. Comparisons of barley varieties from four Nordic countries, and two varieties from the US used as low and high GPC controls, did not show any significant differences depending on their origin country and no differences regarding plant improvement status between the countries. When sequencing Nordic barley varieties, five haplotypes were found for the gene HvNAM-1, and two haplotypes for the gene HvNAM-2. A low polymorphism for both genes indicate a strong natural selection for the consensus haplotype which might be preferable for Nordic climate with a short growing season and cold temperatures. Even though it is not clear what is the cause of the low polymorphism in Nordic barley varieties, they showed a generally higher nutrient content than barley varieties of the high GPC and may be suitable for breeding for a yield with a high nutrient content.
445

Histone modifications and their role in splicing

Wettermark, Anna January 2020 (has links)
Splicing is the process when introns gets removed and exons are spliced together. This is an important step to form a clean mRNA with no unnecessary sequences that could interrupt protein synthesis. There are different types of splicing and some of them need a complex called spliceosome. The spliceosome requires ATP, small nuclear RNAs and splicing factors. The spliceosome and the process splicing can be regulated by epigenetics, and one epigenetic mechanism is histone modification. There are four types of histone modifications; methylation, phosphorylation, ubiquitination and acetylation. They regulate splicing to different extents by altering the chromatin structure, affect the assembly of the spliceosome and regulate the attraction of splicing factors. This review will investigate if histone modifications affect splicing and to what extent. Suggestions for further research regarding the relationship between splicing and histone modifications will also be provided. The review is based on 30 articles and two books and the search was conducted between 30th of March 2020 and 13th of April 2020. Ubiquitination and phosphorylation have a minor effect on splicing meanwhile methylation and acetylation affect splicing in great extent.
446

Epigenetic Regulation of Mitochondrial DNA

Johansson, Jennie January 2020 (has links)
This mini-review investigates and compiles the latest knowledge regarding epigenetic changes on the mammalian mitochondrial DNA and its proteins. Methylation of the DNA, acetylation of the proteins and silencing of genes by short non-coding RNAs are the main epigenetic changes known today to affect mitochondrial DNA, mostly leading to repression. Methylation mainly occurs at non-CpG sites in the main non-coding region called the D-loop, with methylation patterns being cell type specific. Acetylation of proteins are mainly controlled by the deacetylase SIRT3, with its function being correlated to longevity. On the other hand, mitochondrial dysfunction is directly associated with a plethora of diseases, such as neurodegenerative disorders and heart disorders. The mitochondrion and nucleus are immensely dependent on each other and exchange vital proteins and RNAs, with epigenetic changes on one potentially affecting the other. Recent research shows that heteroplasmy is a proven cause of mitochondrial malfunction and that paternal inheritance is possible. The mitochondrial haplotype also shows different vulnerability to certain diets and diseases, leading to the conclusion that the mitochondrial haplotype can be used to more than just tracing human origins, such as to predicting and preventing diseases.
447

Germline Transgenic Methods for Tracking Cells and Testing Gene Function during Regeneration in the Axolotl

Tanaka, Elly M., Khattak, Shahryar, Schuez, Maritta, Richter, Tobias, Knapp, Dunja, Haigo, Saori L., Sandoval-Guzmán, Tatiana, Hradlikova, Kristyna, Duemmler, Annett, Kerney, Ryan 27 October 2015 (has links)
The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration.We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cellcycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible.
448

Environmental toxins trigger PD-like progression via increased alpha-synuclein release from enteric neurons in mice

Pan-Montojo, Francisco, Schwarz, Mathias, Winkler, Clemens, Arnhold, Mike, O' Sullivan, Gregory A., Pal, Arun, Said, Jonas, Marsico, Giovanni, Verbavatz, Jean-Marc, Rodrigo-Angulo, Margarita, Gille, Gabriele, Funk, Richard H. W., Reichmann, Heinz 16 November 2015 (has links)
Pathological studies on Parkinson's disease (PD) patients suggest that PD pathology progresses from the enteric nervous system (ENS) and the olfactory bulb into the central nervous system. We have previously shown that environmental toxins acting locally on the ENS mimic this PD-like pathology progression pattern in mice. Here, we show for the first time that the resection of the autonomic nerves stops this progression. Moreover, our results show that an environmental toxin (i.e. rotenone) promotes the release of alpha-synuclein by enteric neurons and that released enteric alpha-synuclein is up-taken by presynaptic sympathetic neurites and retrogradely transported to the soma, where it accumulates. These results strongly suggest that pesticides can initiate the progression of PD pathology and that this progression is based on the transneuronal and retrograde axonal transport of alpha-synuclein. If confirmed in patients, this study would have crucial implications in the strategies used to prevent and treat PD.
449

An Excess of Gene Expression Divergence on the X Chromosome in Drosophila Embryos: Implications for the Faster-X Hypothesis

Kayserili, Melek A., Gerrard, Dave T., Tomancak, Pavel, Kalinka, Alex T. 30 October 2015 (has links)
The X chromosome is present as a single copy in the heterogametic sex, and this hemizygosity is expected to drive unusual patterns of evolution on the X relative to the autosomes. For example, the hemizgosity of the X may lead to a lower chromosomal effective population size compared to the autosomes, suggesting that the X might be more strongly affected by genetic drift. However, the X may also experience stronger positive selection than the autosomes, because recessive beneficial mutations will be more visible to selection on the X where they will spend less time being masked by the dominant, less beneficial allele—a proposal known as the faster-X hypothesis. Thus, empirical studies demonstrating increased genetic divergence on the X chromosome could be indicative of either adaptive or non-adaptive evolution. We measured gene expression in Drosophila species and in D. melanogaster inbred strains for both embryos and adults. In the embryos we found that expression divergence is on average more than 20% higher for genes on the X chromosome relative to the autosomes; but in contrast, in the inbred strains, gene expression variation is significantly lower on the X chromosome. Furthermore, expression divergence of genes on Muller's D element is significantly greater along the branch leading to the obscura sub-group, in which this element segregates as a neo-X chromosome. In the adults, divergence is greatest on the X chromosome for males, but not for females, yet in both sexes inbred strains harbour the lowest level of gene expression variation on the X chromosome. We consider different explanations for our results and conclude that they are most consistent within the framework of the faster-X hypothesis.
450

Life history and reproductive fitness variation associated with the Y chromosome in Callosobruchus maculatus

Revenikioti, Maria January 2021 (has links)
In the seed beetle Callosobruchus maculatus, the female is the larger sex and the male is the smaller sex. However, males that are almost as large as females can also occur, which is due to a specific Y chromosome haplotype. This Y chromosome polymorphism is not expected since the Y chromosome does not recombine and has lost genetic variation as a consequence. Nevertheless, the Y chromosome manages to maintain this polymorphism. Thus, the questions asked are how this occurs and how the large male Y haplotype persists to exist since previous studies have shown how small males have the higher fitness. In this study, large males were from line SL3b Y and small males were from line SL1b Y. To answer the questions, two important measures of fitness were conducted, mating- and lifetime reproductive success, as well as lifetime-history traits of the SL1b Y and SL3b Y males. Males from line SL3b Y turned out to have a faster growth rate and a shorter development time compared to the SL1b Y males. Both the SL3b Y males with a shorter development time and the SL1b Y males with a longer development time had larger body sizes. Large males also showed to have heavier ejaculate weight and produced more offspring compared to the other male Y haplotype. However, neither of the males had higher pre-mating success. In conclusion, the two male Y haplotypes must coexist in nature since their traits are beneficial in different environments and circumstances.

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