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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.
11

Lernmaterialien effektiv aufbereiten und wiederverwenden

Lorenz, Anja, Fassmann, Lars 13 January 2012 (has links) (PDF)
Hochwertige Schulungsmaterialien für die unternehmensinterne Weiterbildung sind ein erster wichtiger Schritt hin zu einem effektiven Wissensmanagement. Einmal erstellt, können digitale Lerninhalte immer wieder eingesetzt werden. Allerdings ist die Pflege und Anpassung an die Anforderungen verschiedener Zielgruppen und Auslieferungsformate mit herkömmlicher E-Learning-Autorensoftware sehr aufwändig. Nicht so bei serverbasierter Software – sie ermöglicht die Planung, Erstellung, Auslieferung, Verwaltung und Pflege wiederverwendbarer digitaler Lernmaterialien. Dies ist der Ausgangspunkt für eine Vielzahl individueller Weiterbildungsangebote – ohne erneuten Aufwand für die Erstellung der Lerninhalte.
12

Lernmaterialien effektiv aufbereiten und wiederverwenden

Lorenz, Anja, Fassmann, Lars January 2010 (has links)
Hochwertige Schulungsmaterialien für die unternehmensinterne Weiterbildung sind ein erster wichtiger Schritt hin zu einem effektiven Wissensmanagement. Einmal erstellt, können digitale Lerninhalte immer wieder eingesetzt werden. Allerdings ist die Pflege und Anpassung an die Anforderungen verschiedener Zielgruppen und Auslieferungsformate mit herkömmlicher E-Learning-Autorensoftware sehr aufwändig. Nicht so bei serverbasierter Software – sie ermöglicht die Planung, Erstellung, Auslieferung, Verwaltung und Pflege wiederverwendbarer digitaler Lernmaterialien. Dies ist der Ausgangspunkt für eine Vielzahl individueller Weiterbildungsangebote – ohne erneuten Aufwand für die Erstellung der Lerninhalte.
13

Identification of Major Organic Constituents of Saffron Isolated by Solid Phase Extraction and Column Chromatography

Alsudairy, Ziad 31 July 2019 (has links)
Water extracts of saffron, a spice derived from the plant Crocus Sativus L. obtained from India and Iran, were analyzed by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). The components in the extracts were separated on four different solid phase extraction cartridges with four different solvents and by silica gel column. Analysis was done by GC-MS, LC-MS and UV-Vis spectroscopy. The extracts separated into three distinct bands (two bright yellow and one orange) on the silica gel column. Based on GC-MS, the extracted compounds show many structural similarities. Using both extraction techniques, several compounds were identified that were not previously reported to be in saffron. Picrocrocin, safranal, and crocins presence in the extracts were evidenced by absorbance bands at wavelengths of 250 nm, 310 nm and 440 nm, respectively, in their UV-Vis spectra. The LC-MS analysis revealed several high molecular weight compounds that were not observed by GC-MS.
14

Detecção e quantificação de derivados e intermediários de hispidina em fungos bioluminescentes e plantas por LC-MS/MS / Detection and quantification of hispidin derivatives and intermediates in bioluminescent fungi and plants by LC-MS/MS

Martins, Gabriel Nobrega da Rocha 29 June 2018 (has links)
A bioluminescência desperta o interesse humano há muitos séculos. Presente em quatro dos sete reinos taxonômicos, Monera, Chromista, Animalia e Fungi, cada um com mecanismos muito diferentes. Pode-se dizer que o estudo químico da bioluminescência começou com os experimentos de Dubois no século XIX, que cunhou os termos luciferina e luciferase, termos genéricos para o substrato e enzima envolvidos na reação, respectivamente. No caso específico de fungos, o envolvimento de enzimas foi debatido por quase cinco décadas, após a proposta enzimática de Airth e Foerster na década de 1960 e a não enzimática por Shimomura, em 1989. Somente em 2009 a hipótese de Airth e Foerster foi confirmada pelo nosso grupo, seguido da identificação da luciferina fúngica e o envolvimento de hispidina, como molécula precursora, em 2015 pelo grupo de Yampolsky. Para conseguir elucidar mecanismos químicos, a técnica de espectrometria de massas pode ser empregada para a identificação estrutural de reagentes e intermediários destas e de outras reações orgânicas. Após a confirmação do envolvimento de hispidina na bioluminescência de fungos, utilizou-se a técnica de cromatografia líquida acoplada a espectrometria de massas para identificar a presença de hispidina, seus derivados e intermediários precursores, em fungos e em algumas plantas. / Bioluminescence arises human interest for centuries. Occurring in four of seven taxonomical Kingdoms, Monera, Chromista, Animalia and Fungi, each of them with completely different mechanisms. The chemical study of bioluminescence starts in XIX century with Dubois, who coined the terms luciferin and luciferase, generic terms for substrate and enzyme involved in the bioluminescent reaction, respectively. In the specific case of fungi, enzyme involvement has been debated for almost five decades, after the enzymatic proposal by Airth and Foerster, during the 1960 decade, and the non-enzymatic proposal by Shimomura in 1989. It was only in 2009 when the proposal by Airth and Foerster was confirmed by our group, followed by the identification of the fungal luciferin and the involvement of hispidin, as the precursor molecule, in 2015 by Yampolskys group. To elucidate the chemical mechanisms, mass spectrometry can be employed to structural identification of reagents and intermediates on these and other organic reactions. After the confirmation of hispidin involvement in fungi bioluminescence, liquid chromatography coupled with mass spectrometry was uses do identify the presence of hispidin, its derivatives and precursor intermediates in fungi and selected plants.
15

Disposição cinética dos enantiômeros da ifosfamida em pacientes portadoras de câncer de colo do útero / Kinetic disposition of the ifosfamide enantiomers in patients with cervical cancer

Rocha, Otávio Pelegrino 03 April 2013 (has links)
A ifosfamida é um pró-fármaco que apresenta um átomo de fósforo quiral, disponível na clínica como mistura racêmica dos enantiômeros(+)-(R)-ifosfamida e (-)-(S)-ifosfamida para a utilização na quimioterapia. O objetivo do presente estudo foi o de avaliar a disposição cinética dos enantiômeros da ifosfamida em plasma de pacientes portadoras de câncer de colo do útero. As pacientes investigadas (n=6) receberam 2,5 g/m2 de ifosfamida racêmica administrada como infusão de 12 horas, sendo coletadas amostras de sangue imediatamente antes da administração e em 6, 10, 11, 12, 13, 14, 16, 18, 20 e 22 horas após a administração do fármaco. Os enantiômeros da ifosfamida foram quantificados por LC-MS/MS, sendo separados na coluna OD-R em aproximadamente 14 min empregando como fase móvel mistura de acetonitrila e água (20:80) adicionada de 0,2% de ácido fórmico. O método é linear no intervalo de 1-100 ?g de cada enantiômero/mL de plasma a partir de extrações de alíquotas de 25 ?L de plasma, compatíveis com a aplicação em farmacocinética de infusão de curta duração da ifosfamida em pacientes com câncer de colo do útero.A disposição cinética da ifosfamidaéenantiosseletiva, com observação de maiores valores de AUC (437,31 vs349,18 h.?g/mL) e menores valores de clearance(4,17 vs5,22 L/h) para o enantiômero(+)-(R)-ifosfamida. / The prodrugifosfamide has a chiral phosphorus atom, and is available clinically as a racemic mixture of the enantiomers (+)-(R)-ifosfamide and (-)-(S)-ifosfamide for use in chemotherapy. The aim of this study was to evaluate the kinetic disposition of the enantiomers of ifosfamide in plasma of patients with cancer of the cervix. The investigated patients (n = 6) received 2.5 g/m2 of racemic ifosfamide administered as infusion of 12 hours and blood samples were collected immediately before administration and at 6, 10, 11, 12, 13, 14, 16, 18, 20 and 22 hours after drug administration. The enantiomers of ifosfamide were quantified by LC-MS/MS and were separated in an OD-R column in about 14 min using as mobile phase a mixture of acetonitrile and water (20:80) plus 0.2% of formic acid. The method is linear within the range of 1-100 mg of each enantiomer/mL of plasma from extractions of 25 mL aliquots of plasma, suitable for the application in pharmacokinetics of short duration infusion of ifosfamide in patients with cervical cancer. The kineticdisposition of ifosfamide is enantioselective, with observation of higher values of AUC (437.31 vs 349.18 h.?g/mL) and lower values of clearance (4.17 vs 5.22 L/h) for the enantiomer (+)-(R)-ifosfamide.
16

Detecção e quantificação de derivados e intermediários de hispidina em fungos bioluminescentes e plantas por LC-MS/MS / Detection and quantification of hispidin derivatives and intermediates in bioluminescent fungi and plants by LC-MS/MS

Gabriel Nobrega da Rocha Martins 29 June 2018 (has links)
A bioluminescência desperta o interesse humano há muitos séculos. Presente em quatro dos sete reinos taxonômicos, Monera, Chromista, Animalia e Fungi, cada um com mecanismos muito diferentes. Pode-se dizer que o estudo químico da bioluminescência começou com os experimentos de Dubois no século XIX, que cunhou os termos luciferina e luciferase, termos genéricos para o substrato e enzima envolvidos na reação, respectivamente. No caso específico de fungos, o envolvimento de enzimas foi debatido por quase cinco décadas, após a proposta enzimática de Airth e Foerster na década de 1960 e a não enzimática por Shimomura, em 1989. Somente em 2009 a hipótese de Airth e Foerster foi confirmada pelo nosso grupo, seguido da identificação da luciferina fúngica e o envolvimento de hispidina, como molécula precursora, em 2015 pelo grupo de Yampolsky. Para conseguir elucidar mecanismos químicos, a técnica de espectrometria de massas pode ser empregada para a identificação estrutural de reagentes e intermediários destas e de outras reações orgânicas. Após a confirmação do envolvimento de hispidina na bioluminescência de fungos, utilizou-se a técnica de cromatografia líquida acoplada a espectrometria de massas para identificar a presença de hispidina, seus derivados e intermediários precursores, em fungos e em algumas plantas. / Bioluminescence arises human interest for centuries. Occurring in four of seven taxonomical Kingdoms, Monera, Chromista, Animalia and Fungi, each of them with completely different mechanisms. The chemical study of bioluminescence starts in XIX century with Dubois, who coined the terms luciferin and luciferase, generic terms for substrate and enzyme involved in the bioluminescent reaction, respectively. In the specific case of fungi, enzyme involvement has been debated for almost five decades, after the enzymatic proposal by Airth and Foerster, during the 1960 decade, and the non-enzymatic proposal by Shimomura in 1989. It was only in 2009 when the proposal by Airth and Foerster was confirmed by our group, followed by the identification of the fungal luciferin and the involvement of hispidin, as the precursor molecule, in 2015 by Yampolskys group. To elucidate the chemical mechanisms, mass spectrometry can be employed to structural identification of reagents and intermediates on these and other organic reactions. After the confirmation of hispidin involvement in fungi bioluminescence, liquid chromatography coupled with mass spectrometry was uses do identify the presence of hispidin, its derivatives and precursor intermediates in fungi and selected plants.
17

Pharmacokinetics and cytoprotective evaluation of Caffeic Acid Phenethyl Amide and fluorinated derivatives against oxidative stress

Yang, John 26 February 2013 (has links)
Ischemic injury occurs when the flow of blood is reduced or blocked to an area of the body and can cause significant tissue damage by generation of reactive oxygen species (ROS), activation of apoptotic pathways and through induction of the inflammatory response. Restoration of blood flow and reperfusion of the blocked site, while essential, can generate a second injury that itself needs to be controlled. Together the two injuries are termed ischemia/reperfusion (I/R) injury. This type of injury is frequently encountered in medicine and is a major medical problem. Therapeutic strategies to combat I/R injury include the introduction of compounds that can scavenge ROS or can induce metabolic pathways with the effect of inhibiting apoptosis. Caffeic Acid Phenethyl Ester (CAPE), a polyphenolic compound found in propolis, has been shown to protect a variety of cells types against ROS in vitro and has also been shown to induce a variety of genes including hemeoxygenase 1 (HMOX-1) , an enzyme that has been implicated in a cytoprotective pathway. Despite showing significant cytoprotection of cells against oxidant stress in vitro, CAPE is readily hydrolyzed in plasma and is also quickly removed from circulation. This result may explain the limited cytoprotective effects of CAPE in vivo. We have synthesized a series of CAPE amide derivatives, including Caffeic Acid Phenethyl Amide (CAPA), with the aim of improving CAPE’s stability properties while maintaining the cytoprotective effects of the parent compound. We found that CAPA, in addition to 2 other amide derivatives, were able to protect human umbilical vein endothelial cells (HUVEC) against ROS to a similar degree as CAPE. In addition, we have observed significant improvement in plasma stability of CAPA over CAPE at multiple temperatures. The elimination half-life of CAPA from the systemic circulation was also seen to be significantly improved over CAPE following intravenous administration to male Sprague-Dawley rats. The longer residence time of CAPA over CAPE in circulation may potentially result in greater cytoprotection in vivo. / text
18

Classifying learning management platforms by examining features and educational affordances

Sung, Woon Hee 18 November 2011 (has links)
Learning management systems(LMSs) have become one of the most common computer systems adopted at universities, colleges and distance learning organizations. In order to identify different features and accordance of each LMS, LMSs’ features were compared by using four different categories; communication tools, productivity and student involvement tools, course delivery tools, and administration tools. Based upon the comparison of the different features affecting different usage patterns, this paper proposes a classification of seven selected LMSs; ANGEL, Blackboard, Moodle, Sakai, WebCT, Ning and Elgg. These seven LMSs are classified into three groups according to systems’ pedagogical adaptability and technological usability. The classification seeks to understand the possibilities and limitations of what these classified groups of LMSs can accomplish and is used to suggest a suitable usage in order to support teaching and learning. The proposed classification implies the need of future exploratory case study analyzing teaching and learning practices according to the classification. / text
19

Aspects of Nitrogen Metabolism in Symbiotic Cnidarians

Boutilier, Ryan Michael 24 August 2012 (has links)
The pathway of seawater ammonium assimilation and influence of light on amino acid synthesis remain unresolved in cnidarian symbioses. Labeled ammonium (10 μM 15NH4Cl) in seawater was used to trace the pathway of the incorporation into amino acids in host tissue, Zoanthus sp., and zooxanthellae, Symbiodinium microadriaticum. Freshly isolated zooxanthellae were exposed to 20 μM 15NH4Cl with coral homogenate to evaluate the role of host factors on amino acid synthesis. High performance liquid chromatography and mass spectrometry was used to measure percent labeling and concentrations of amino acids. In zooxanthellae, ammonium was assimilated into glutamine likely via glutamine synthetase and into glutamate via glutamine 2-oxoglutarate amidotransferase. Interrupting photosynthesis with DCMU did not inhibit glutamine and tryptophan synthesis however reduced the 15N-enrichment of glutamate, aspartate, and ornithine in zooxanthellae, as well as arginine, ornithine, and lysine in host tissue. Coral homogenate had little effect on the 15N-enrichment of glutamine, aspartate, and alanine in freshly isolated zooxanthellae. Evidence is presented to support the uptake of ammonium ions and data shows that glutamine and not glutamate is translocated to the coral host.
20

Tetracyclines In Swine Waste

Jones, Natalie Kaye 01 May 2014 (has links)
Antibiotics are added to animal feeds as prophylactic agents and to encourage weight gain in livestock. However, there is concern that the widespread use of antibiotics in animal agriculture encourages for the selection of resistance genes and has contributed to the rise of multiply antibiotic resistant strains of pathogenic bacteria. For this reason, there is interest in quantifying antibiotics in environmental samples. The determination of three antibiotics in swine waste, namely chlortetracycline, tetracycline and oxytetracycline, using LC-MS with electrospray ionization is presented here in. Antibiotics from swine waste were quantified across the lifespan of the swine. Trends were present in each of the four life stages (gestation, farrowing, nursery, and finishing). The nursery stage of life presented the most dominate concentrations and the most consistent trend in antibiotic concentrations.

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