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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.
31

Analýza sacharidů a markerů spalování dřeva v atmosférických aerosolech / Analysis of saccharides and markers of wood combustion in atmospheric aerosols

Kubátková, Nela January 2011 (has links)
Diploma thesis deals with the analysis of saccharides and markers of biomass and wood combustion in atmospheric aerosol, PM2,5. Theoretic part is focused on general characterisation of atmospheric aerosols and on the properties, sources and analysis methods of selected analysed organic compounds. The experimental part is focused on the optimization of method for simultaneous analysis of saccharides and tracers from biomass and wood combustion. Optimization of method includes selection of solvent for the extraction of compounds and optimization of derivatization process and GC/MS analysis. The optimized method was then applied for the analysis of selected compounds in real aerosol samples in the size fraction PM2.5. The concentrations of analysed compounds were compared in term of sampling seasons.
32

THERMAL ANALYSIS AS AN IMPORTANT RESEARCH TOOL FOR COLLEGES AND UNIVERSITIES

Fruscella, Jeffrey Allen 15 December 2011 (has links)
No description available.
33

The Medicago truncatula sucrose transporter family : sugar transport from plant source leaves towards the arbuscular mycorrhizal fungus

Doidy, Joan 23 May 2012 (has links) (PDF)
In plants, long distance transport of sugars from photosynthetic source leaves to sink organs comprises different crucial steps depending on the species and organ types. Sucrose, the main carbohydrate for long distance transport is synthesized in the mesophyll and then loaded into the phloem. After long distance transport through the phloem vessels, sucrose is finally unloaded towards sink organs. Alternatively, sugar can also be transferred to non‐plant sinks and plant colonization by heterotrophic organisms increases the sink strength and creates an additional sugar demand for the host plant. These sugar fluxes are coordinated by transport systems. Main sugar transporters in plants comprise sucrose (SUTs) and monosaccharide (MSTs) transporters which constitute key components for carbon partitioning at the whole plant level and in interactions with fungi. Although complete SUTs and MSTs gene families have been identified from the reference Dicot Arabidopsis thaliana and Monocot rice (Oriza sativa), sugar transporter families of the leguminous plant Medicago truncatula, which represents a widely used model for studying plant-fungal interactions in arbuscular mycorrhiza (AM), have not yet been investigated.With the recent completion of the M. truncatula genome sequencing as well as the release of transcriptomic databases, monosaccharide and sucrose transporter families of M. truncatula were identified and now comprise 62 MtMSTs and 6 MtSUTs. I focused on the study of the newly identified MtSUTs at a full family scale; phylogenetic analyses showed that the 6 members of the MtSUT family distributed in all three Dicotyledonous SUT clades; they were named upon phylogenetic grouping into particular clades: MtSUT1-1, MtSUT1-2, MtSUT1-3, MtSUT2, MtSUT4-1 and MtSUT4-2. Functional analyses by yeast complementation and expression profiles obtained by quantitative RT-PCR revealed that MtSUT1-1 and MtSUT4-1 are H+/sucrose symporters and represent key members of the MtSUT family. Conservation of transport capacity between orthologous leguminous proteins, expression profiles and subcellular localization compared to previously characterized plant SUTs indicate that MtSUT1-1 is the main protein involved in phloem loading in source leaves whilst MtSUT4-1 mediates vacuolar sucrose export for remobilization of intracellular reserve.The AM symbiosis between plants and fungi from the phylum Glomeromycota is characterized by trophic exchanges between the two partners. The fungus supplies the autotrophic host with nutrients and thereby promotes plant growth. In return, the host plant provides photosynthate (sugars) to the heterotrophic symbiont. Here, sugar fluxes from plant source leaves towards colonized sink roots in the association between the model leguminous plant M. truncatula and the arbuscular mycorrhizal fungus (AMF) Glomus intraradices were investigated. Sugar transporter candidates from both the plant and fungal partners presenting differential expression profiles using available transcriptomic tools were pinpointed. Gene expression profiles of MtSUTs and sugar quantification analyses upon high and low phosphorus nutrient supply and inoculation by the AMF suggest a mycorrhiza-driven stronger sink in AM roots with a fine-tuning regulation of MtSUT gene expression. Conserved regulation patterns were observed for orthologous SUTs in response to colonization by glomeromycotan fungi.In parallel, a non-targeted strategy consisting in the development of a M. truncatula - G. intraradices expression library suitable for yeast functional complementation and screening of symbiotic marker genes, similar to the approach that led to the identification of the first glomeromycotan hexose transporter (GpMST1), has been developed in this study. [...]
34

Can sugar be good for your oral health? Correlations between caries and levels of bound monosaccharides in whole saliva

Vikström, Hanna, Shala, Kosovare January 2017 (has links)
Introduktion och syfte: Kariesutveckling influeras av faktorer hos både värd och bakterier. Men när olika individer exponeras för samma nivåer av externa riskfaktorer, är en del individer mer mottagliga för karies jämfört med andra. En förklaring skulle kunna vara olika glykosylering av glykoprotein i saliven. I denna pilotstudie undersökte vi skillnaden i nivåer av monosackariderna sialinsyra, fukos och galaktos hos personer som aldrig haft karies och personer som har/har haft karies. Syftet var även att undersöka om plackenzym kan vara en modifierare av nämnda glykoprotein.Material och metod: Två grupper, med 10 individer i varje, inkluderades i studien. Ena gruppen hade DMFT = 0 och den andra DMFT ≥ 1. Saliv och plack samlades och innehållet av bundna monosackarider (sialinsyra, fukos och galaktos) samt glykosidaser (sialidas, β-fukosidas, β-galaktosidas, α-glukosidas och N-acetylglukosaminidas) analyserades med en fluorometer. Även salivflödet kalkylerades.Resultat: Innehållet av både sialinsyra och galaktos var signifikant högre i gruppen med DMFT = 0, medan innehållet av fukos inte skilde sig åt signifikant mellan grupperna. Ingen signifikant skillnad kunde ses mellan de två grupperna avseende enzymaktivitet och salivflöde.Konklusion: Högre nivåer av bunden sialinsyra och galaktos fanns hos gruppen med DMFT = 0. Resultaten indikerar att dessa monosackarider kan vara en möjlig markör för oral hälsa. Större longitudinella studier behövs för att verifiera sambandet. / Introduction and aim: Caries development is affected by factors within bacteria and host. But when different individuals are exposed to same levels of external risk factors, some individuals are still more susceptible to caries. One explanation could be different glycosylation of salivary glycoproteins. In this pilot study, we investigated the difference in levels of the monosaccharides sialic acid, fucose and galactose between individuals with or without previous caries experience. We also aimed to investigate if plaque glycosidases could be a modifier of these glycoproteins.Material and method: Two groups, with 10 subject in each, were included in this study. One group had DMFT = 0 and the other DMFT ≥ 1. Saliva and plaque were collected and content of bound monosaccharides (sialic acid, fucose and galactose) and glycosidases (sialidase, α-fucosidase, β-galactosidase, α-glucosidase and N-acetylglucosaminidase) were detected using absorbance and fluoroscens respectively. Salivary flow rate was also measured.Results: Content of both sialic acid and galactose were significantly higher in the group with DMFT = 0, while the content of fucose did not differ significantly between the groups. No significant differences could be seen between the two groups (DMFT = 0 and DMFT ≥ 1) regarding any of the investigated glycosidases and salivary flow rate. Conclusion: Higher levels of bound sialic acid and galactose were found in the group with DMFT = 0 and the results indicate that these monosaccharides could be a possible marker for oral health. Larger longitudinal studies are needed to verify this correlation.

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