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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.
1

Minoritetselever, språk och matematik

Sikström, Linda January 2005 (has links)
Huvudsyftet med studien har varit att undersöka hur minoritetselever kan tillgodogöra sig svenska språket och matematikundervisningen på bästa sätt. I uppsatsen redogörs för matematiskt och språkligt lärande, samt den aktuella forskning som finns i ämnet. Detta ligger till grund för hur studien är utformad. Undersökningsgruppen består av 89 elever från åk 3 och 4. Eleverna är nivågrupperade i A- till E-nivå, beroende på språklig kompetens hos den enskilda eleven. Undersökningen visar att ju mer den enskilda eleven är nybörjare i svenska desto sämre resultat i svensktesten har den enskilda eleven haft på testen i matematik. Minoritetselever måste, i större utsträckning än vad som sker idag, erbjudas hjälp i svenska språket. En av orsakerna till att minoritetselever har svårt med matematiskt och språkligt lärande är att skolan har ett språk och samhället ett annat. Pedagogen behöver fundera på vilket sätt undervisningen bäst kan kombinera ett (skolans) formellt språkbruk med elevernas (eget) informella språk. Detta för att undervisningen ska komma alla elever tillgodo på bästa möjliga sätt.Nyckelord: minoritetselever, språk, matematik, skolan, modersmål, sv2 / The main purpose of the study has been to investigate how minotity students can profit best from the teaching of the Swedish language and mathematics. In this work, mathematics and linguistic learning is described along with the currunt research in the field. This forms the basis of how this study is designed. The examined group consists of 89 pupils in their third (3) and fourth (4) year of school. The pupils are grouped into levels A to E-level, dependig on the linguistic capability of the single student. The study shows that pupils who are at a beginner level in the Swedeish language scored worse on the Swedish test in mathematics. Minority students must, to a greater extent than today, be offered help in learning the Swedish language. One of the reasons that minority have problems with mathematics and linguistic learning is that the school and society formal use of language ande the students informal use of language best can be combined when teaching. This is necessary if all students are to profit from the education in an optimal way.Keywords: Minoritystudent, language, mathematics, school, native language, sv 2
2

Molecular mechanisms of neural plasticity after spinal cord injury in the lamprey central nervous system

Lau, Billy You Bun 12 November 2013 (has links)
Spinal cord injury induces anatomical plasticity throughout the nervous system, including distant locations in the brain. Several types of injury-induced plasticity have been identified, such as neurite sprouting, axon regeneration and synaptic remodeling. However, the molecular mechanisms involved in anatomical plasticity after injury are unclear, as is the extent to which injury-induced plasticity in the brain is conserved across vertebrate lineages. Here, I used lampreys to identify the molecular mechanisms in mediating anatomical plasticity, because lampreys undergo anatomical plasticity and functional recovery after a complete spinal cord transection. Due to their robust roles in neurite outgrowth during neuronal development, I examined synapsin and synaptotagmin for their potential involvement in anatomical plasticity after injury. I found increased synapsin I mRNA throughout the lamprey brain as well as increased protein levels of synapsin I, phospho-synapsin (Ser 9) and synaptotagmin in the lamprey hindbrain after injury, suggestive of anatomical plasticity. Anatomical plasticity was confirmed at the ultrastructural level, where I found increased neurite density in the lamprey hindbrain after injury. Other molecular mechanisms that promote anatomical plasticity have been previously identified, such as cyclic AMP (cAMP). However, the cellular mechanisms and the molecular targets of cAMP in mediating anatomical plasticity are unclear. My investigation of cAMP revealed that cAMP enhanced the number of regenerated axons beyond the lesion site in lampreys after injury. For the first time in a spinal cord injury model, I found cAMP prevented the death of axotomized neurons that normally have a high tendency to die after injury. In addition, cAMP promoted more regenerating axons to re-grow in straighter paths rather than turning rostrally towards the brain stem. At the molecular level, I found cAMP increased synaptotagmin protein level at the regenerating axon tips, suggestive of enhanced axon elongation. Taken together, my results show that neurite sprouting in the brain and the cAMP-enhanced axon regeneration are conserved responses in vertebrates after spinal cord injury. In addition, my results suggest that at least some developmental pathways are activated during injury-induced and cAMP-enhanced anatomical plasticity. Further understanding of these pathways will provide insights for improving recovery after spinal cord injury. / text
3

Solute Carriers in Metabolism : Regulation of known and putative solute carriers in the central nervous system

Lekholm, Emilia January 2017 (has links)
Solute carriers (SLCs) are membrane-bound transporter proteins, important for nutrient, ion, drug and metabolite transport across membranes. A quarter of the human genome codes for membrane-bound proteins, and SLCs make up the largest group of transporter proteins. Due to their ability to transport a large repertoire of substances across, not just the plasma membrane, but also the membrane of internal organelles, they hold a key position in maintaining homeostasis affecting metabolic pathways. Unfortunately, some of the more than 400 identified SLCs are still not fully characterized, even though a quarter of these are associated with human disease. In addition, there are about 30 membrane-bound proteins with strong resemblance to SLCs, of which very little is known. The aim of this thesis is to characterize some of these putative SLCs, focusing on their localization and function in the central nervous system. Since many of the known SLCs play a vital part in metabolism and related pathways, the response to different nutritional conditions has been used as a key method. MFSD14A and MFSD14B, characterized in Paper I, are putative SLCs belonging to the Major Facilitator Superfamily (MFS) and found to be neuronal, differentially expressed in the mouse central nervous system and transiently upregulated in mouse embryonic cortex cultures due to amino acid deprivation. They were also altered in areas of the mouse brain after starvation as well as after high fat diet. In Paper II, the effect on gene regulation due to complete amino acid starvation was monitored in a mouse hypothalamic cell line and 47 different genes belonging to SLCs, or putative SLCs, were found to be affected. Of these, 15 genes belonged to already known amino acid transporters, whereas 32 were putative SLCs with no known function or SLCs not known to react to amino acids. The three SV2 proteins, SV2A, SV2B and SV2C, were studied in Paper III using human neuroblastoma cell lines. The high metabolic state of cancers often result in an upregulation and alteration of transporter proteins, and alterations of the SV2 proteins were found following different treatments performed in this study. Paper IV focused on putative SLCs of MFS type and their role in glucose metabolism. Mouse embryonic cortex cultures were subjected to glucose starvation and the gene expression of 19 putative transporters were analyzed. All but four of the putative transporters were affected either at 3h or 12h of glucose deprivation. In conclusion, several SLCs and putative SLCs studied in this thesis are strongly affected by alteration in metabolism, either due to amino acids or glucose or both. This makes the putative SLCs dynamic membrane-bound proteins, possibly transporters, highly affected by nutritional status and most likely regulated to maintain homeostasis.
4

The cytotoxic effects of malondialdehyde on human lung fibroblast cells

Yates, Sally A. January 2015 (has links)
Malondialdehyde (MDA) is a mutagenic and carcinogenic product of lipid peroxidation which has also been found at elevated levels in smokers. MDA reacts with nucleic acid bases to form pyrimidopurinone DNA adducts, of which 3-(2-deoxy-β-D-erythro-pentofuranosyl)pyrimidol[1,2-α]purin-10(3H)-one (M1dG) is the most abundant and has been linked to smoking. Mutations in the TP53 tumour suppressor gene are associated with half of all cancers. This research applied a multidisciplinary approach to investigate the toxic effects of MDA on the human lung fibroblasts MRC5, which have an intact p53 response, and their SV40 transformed counterpart, MRC5 SV2, which have a sequestered p53 response. Both cell lines were treated with MDA (0-1000 µM) for 24 and 48 h and subjected to a variety of analyses to examine cell proliferation, cell viability, cellular and nuclear morphology, apoptosis, p53 protein expression, DNA topography and M1dG adduct detection. For the first time, mutation sequencing of the 5’ untranslated region (UTR) of the TP53 gene in response to MDA treatment was carried out. The main findings were that both cell lines showed reduced proliferation and viability with increasing concentrations of MDA, the cell surface and nuclear morphology were altered, and levels of apoptosis and p53 protein expression appeared to increase. A LC MS-MS method for detection of M1dG adducts was developed and adducts were detected in CT-DNA treated with MDA in a dose-dependent manner. DNA appeared to become more fragmented with increasing MDA concentration, and the number of mutations in the 5’ UTR region of the TP53 gene also increased. The majority of mutations observed were insertions, compared to lung cancer mutation data where the majority were G to T transversions. This was unexpected, suggesting that tobacco smoke compounds have a different role in mutagenesis than endogenous lipid peroxidation. Thus, MDA has been found to have a clear effect on human lung fibroblasts at both the cellular and DNA level.

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