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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.
241

Stanovení vitaminu C kapalinovou chromatografií v plodech jednotlivých odrůd méně známých druhů ovoce / Determination of C vitamin by HPLC in fruits of individual cultivars of less known kinds of fruits

Cetkovská, Jitka January 2009 (has links)
Diploma thesis deals with determination of vitamin C in various cultivars of sea buckthorn (Hippophae rhamnoides, L.) and quince (Cydonia oblonga, Mill.). In theoretical part, there are mentioned basic information about these less known fruit species, their medically significant substances and utilization of these fruits. Various methods for determination of vitamin C are discussed with focus on HPLC and extraction of vitamin C from the matrix. In experimental part, the most suitable column (Gemini C18, 150 x 4,6 mm; 5 m) was chosen from six various columns. Analysis of vitamin C in various cultivars of quince and sea buckthorn fruits were carried out on this column. The various types of matrix preparation and two different separation systems (method with oxalic acid and system with phosphate buffer and methanol as a mobile phases) were investigated too. Vitamin C was determined as an ascorbic acid.
242

Srovnání méně známých druhů ovoce z hlediska obsahu vitaminu C / Comparison of vitamin C content between less known kinds of fruit

Mařáková, Veronika January 2010 (has links)
This thesis deals with the determination of vitamin C in different varieties of cornelian cherry (Cornus mas) and mountain ash (Sorbus aucuparia). The theoretical part describes the botanical characteristics of both plants, the extension in the CZ and in the world, methods of reproduction, the content of meaningful health substances and the importance of both plants in food-processing industry. Attention is paid to vitamin C, which is in their fruits in high quantity. Conclusion of the theoretical part discusses various methods of determination of vitamin C. The aim of the experimental part was to comparison of the vitamin C content in different varieties cornelian cherry and mountain ash. The chosen method for the determination of vitamin C by high performance liquid chromatography (HPLC) with UV detection was first tested on standards. Selected validation parameters of this method was then determined. Validated method was used to determine the content of vitamin C in nine varieties cornelian cherry and six varieties of the mountain ash. For comparison were also tested some samples of the determination of total vitamin C after reducing dehydroascorbic acid by using dithiothreitol (DTT).
243

Stanovení některých nutričních faktorů ve vybraných druzích ovoce / Determination of some nutrition factors in selected kinds of fruit

Smělá, Margita January 2011 (has links)
Diploma thesis is concerned with determination of some nutrion factors and vitamin C in various cultivars of apples (Pirus Malus, L.) and quinces (Cydonia oblonga, Mill.). In theoretical part there are described general characterization in selected kinds of fruits, their medically significant sunstances and utilization of these fruits. Main focus is paid to vitamin C. There are described its chemical properties and effect for human health. Various methods for determination of some nutrion factors with focus on determination of vitamin C by high-performance liquid chromatography. In experimental part, total of 27 various cultivars of aplles and 16 various cultivars of quinces were analyzed. These cultivars are from grower station Faculty of garden of Mendel university. For determitation vitamin C was used by high-performance liquid chromatography. Vitamin C was determination as an ascorbic acid. Some nutrion factors were analyzed in experimental part. There were analyzed dry matter, total flavonoids, total phenolics and titratable acid in various cultivars of apples and quinces. There were compared of some various cultivars after representation and content of significant substances as result. The last part of thesis was sensory analysis of apples.
244

Analýza šťáv vybraných odrůd černého rybízu / Analysis of juices of selected blackcurrant varieties

Kaniová, Lenka January 2015 (has links)
The work deals with the chemical analysis of juices selected varieties of black currant (Ribes nigrum L.). The theoretical part is divided into three main chapters. In the first chapter there are short botanical characteristics of black currants, content of biologically active substances in fruit and utilization of black currant fruit in food industry. In the second chapter there are characteristics, importance and methods of determination of phenolic compounds. Vitamin C is describe in the last chapter, its characteristics, importance and methods of determination. Experimental part describes determination of three chemical characteristic of black currant fruits: content of total phenolic compounds, content of total anthocyanins and content of vitamin C. Twelve modern varieties of black currant were selected for determination. Based on these results, it is possible to deduce the more important varieties. The content of total phenolic compounds was in the range of 326,7–641,4 mg•100 g-1 in all samples. The content of total anthocyanins was analysed in the range from 102,5 to 284,5 mg•100 g-1 in all samples. And content of vitamin C was in the range from 82,0 to 379,1 mg•100 g-1 in all samples. The overall comparison of the varieties of black currant was found, the varieties Ceres, Ben Hope, Ben Lomond, Démon and Ometa are the most promising varieties in terms of the content of the above mentioned compounds.
245

Studium vlivu arbuskulárních mykorhizních hub na jakostní, hospodářské a nutriční parametry kultury póru pravého (Allium porrum L.)

Kučová, Lucie January 2016 (has links)
This dissertation deals with the use of arbuscular mycorrhizal fungi in vegetable production. The completion of knowledge and confirmation of scientific hypothesis in practise is necessary to be done for each vegetable species. For these reasons the dissertation establishes the entire growing process of the leek (Allium porrum L.). The experiment explores the influence of arbuscular mycorrhizal fungi on the physiological, nutritional and yield parameters of the leek crop. The literary review focuses on the mycorrhizal symbiosis as entire complex and shows an arbuscular mycorrhizal symbiosis, its basic function, usage and impact on plants. Several parts of literary review mention the transfer of elements from the soil to the roots of plants by arbuscular mycorrhizal fungi and currently valid nomenclature is also listed. The experimental part is focused on a trial with several species of arbuscular mycorrhizal fungi and their combinations. The morphological evaluation of pre-cultivated leeks and also field grown plants was focused on the comparison of length and weight of the plants. Nutritional assessments are focused primarily on the vitamin C, total antioxidant capacity, content of nitrates, content of phosphorus and nitrogen in plant tissues. In the pursuance to our results, it is possible to say, that certain variants of arbuscular mycorrhizal fungi had positive influence on the height of pre-cultivated leeks, and a positive trend was also confirmed during the evaluation of the content of antioxidants. The amount of heavy metals in plant tissues was reduced by combination of fungi R. intraradices and C. claroideum. The positive influence of inoculation was also observed at the reduction of nitrates in 2014. Overall, we can say that using of arbuscular mycorrhizal fungi in the cultivation of leeks (Allium porrum L.) contribute to a positive effect on plants and yield, especially in the years with extreme weather conditions during growing season.
246

Faktory ovlivňující množství vitaminu C v zeleném koření

Průchová, Simona January 2019 (has links)
The thesis deals with particular green spice like Mentha longifolia L., Mentha spicata L., Mentha tomentosa Sm. 'Fíková', Mentha suaveolens Ehrt. 'Jablečná', Mentha piperita 'Persephone', Origanum vulgare L., Origanum heracleoticum L., Origanum vulgare L.'Aureum', Origanum vulgare L. 'Thumbles variety', Satureja montana L., Satureja hortensis L., Salvia glutinosa L., Salvia verbanaca L., Salvia verticilata L., Salvia lyrata L., Salvia przewalskii Maxim, Salvia officinalis L. 'Purpurascens', Allium nutans L., Allium stipitatum L., Allium tuberosum Rottl. Ex Spreng. In theoretic part a botanical charakteristics of the spice, legislation concerning the green spice, new information about vitamin C and factors influencing the content of ascorbic acid in plants are described. In practical part, the content of vitamin C in vegetative and generative growth phase has been determined. Results have been evalueted and compared.
247

Preventive Effect of Antioxidative Nutrient‐Rich Enteral Diet Against Liver Ischemia and Reperfusion Injury / 肝虚血再灌流障害に対する抗酸化栄養素強化食の保護効果

Miyauchi, Tomoyuki 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21648号 / 医博第4454号 / 新制||医||1034(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妹尾 浩, 教授 小池 薫, 教授 Shohab YOUSSEFIAN / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DGAM
248

The Antioxidant Defense Network: Synergistic Combinations to Prevent Oxidative Damage

Clement, Amy Marie 13 August 2008 (has links) (PDF)
One of the matchless ironies of the human body is its requirement for the highly reactive oxygen molecule, which has been clearly implicated in many diseases and the aging processes. Oxidants produced by metabolic processes damage cells by starting chemical chain reactions including oxidation of DNA and proteins as well as lipid peroxidation. Damage to DNA can cause mutations and lead to cancer if not reversed by DNA repair mechanisms. Damage to proteins causes enzyme inhibition, denaturation and protein degradation. Lipid peroxidation can cause cell lysis as well as creating mutagenic and carcinogenic by-products. The human body contains antioxidants and enzymes that together work to prevent oxidative damage to cellular components. By and large antioxidants either prevent these reactive oxygen species from being formed or remove them before they cause damage. There are many theories currently that tout the superior nature of diverse antioxidant combinations. One such theory is by Dr. Lester Packer of The University of California at Berkley. Dr. Packer puts forth the hypothesis that there is a superlative combination of five antioxidants that have the ability to "recharge" one another both in the blood plasma and intracellularly. This would result in a greater quality of antioxidant protection for an extended time. The current study evaluates Dr. Packer's theory of antioxidant combination from his book The Antioxidant Miracle. The decay rate of the antioxidants vitamin E, vitamin C, lipoic acid, glutathione, and coenzyme Q10 alone and in combination were determined using the ORAC (Oxygen Radical Absorbance Capacity) assay. The majority of the antioxidants retained activity for longer periods of time when tested alone, rather than in combination as Dr. Packer's theory would suggest. The assay was also preformed (using the same antioxidants and combinations) on oxidatively damaged Raji cancer cells. Cell viability and uptake of antioxidants into the cytoplasm were monitored. Finally, a variety of multivitamins were subjected to the ORAC assay and their antioxidant capacity compared to that of the "Packer Combination". The results suggest that multivitamins are superior antioxidants than the Packer ratio listed in The Antioxidant Miracle.
249

Cord Blood CD34+ Expansion Using Vitamin-C: An Epigenetic Regulator

Almoflehi, Sakhar 09 November 2020 (has links)
Vitamin-C (Vit-C) has been shown to modulate hematopoietic stem cells and leukemia stem cell frequency in-vivo. Herein, Vit-C analogue, L-ascorbic acid 2-phosphate (AA2P), was investigated as a new potential HSC expansion agonist. Cord blood CD34+ cells were expanded in cultures with or without AA2P. AA2P induced a 2-fold increase in the expansion of stem and progenitor subsets including lymphoid-primed multi-potential progenitors (p<0.05, n=3) and functional colony forming progenitors. The functional properties of AA2P grafts was evaluated with a xenotransplant model. Superior platelet levels in the periphery (p<0.05) and human bone marrow engraftment (median 75% hCD45+ cells for AA2P Vs. 48% for PBS control at week-22, n=3, p<0.05) was detected in AA2P cohorts Vs. control. In summary, my results demonstrate that AA2P is a new stem and progenitor expansion agonist with AA2P-expanded stem and progenitor cells capable of increased engraftment and higher platelet recovery. These findings may aid to overcome cord blood limitations; thereby, improving clinical relevance.
250

Investigations Into the Mechanisms of Vitamin C Uptake in Rodent and Human Lens Epithelial Cells

Obrenovich, Mark E. 17 June 2008 (has links)
No description available.

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