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Dissertations / Theses on the topic 'Chemistry of bitter substances'

Author: Grafiati

Published: 4 June 2021

Last updated: 12 February 2022

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1

Lawson, David R. "Chemistry and biochemistry of Solanum chacoense, bitter steroidal alkaloids /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487843688958887.

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2

Mirzaee, Mehrdad. "Development of diagnostic tools to predict incidence of bitter pit during apple storage." Thesis, University of Greenwich, 2015. http://gala.gre.ac.uk/18210/.

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Bitter pit is an important physiological disorder of many apple cultivars where the low uptake and poor distribution of calcium within the cortex of apples pervades. Controlled atmosphere storage and application of 1-MCP (SmartFreshSM) can delay the onset of bitter pit symptoms by delaying maturity and senescence; however, significant losses may occur in long-term stored apples. It is hard to detect internal bitter pit using external examination alone. Previous studies have focused on improving pre-harvest prediction and curative treatments before harvest. Present prediction models are based o

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3

Alotaibi, Yousef. "Chemistry of humic-like substances in the atmosphere." Thesis, University of East Anglia, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405706.

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4

Chiwona-Karltun, Linley. "A reason to be bitter : cassava classification from the farmers' perspective /." Stockholm : [Karolinska institutets bibl.], 2001. http://diss.kib.ki.se/2001/91-7349-078-4/.

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5

Bostanian, Levon Artine. "Novel drug delivery systems for relatively insoluble substances /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu14878617968179.

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6

O'Loughlin, Edward John. "Association of organotin compounds with aquatic humic substances /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487946776023338.

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7

Lacroix, Pauline M. "Methods for total drug and related substances in pindolol." Thesis, University of Ottawa (Canada), 1991. http://hdl.handle.net/10393/7885.

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A liquid chromatographic method for the assay of pindolol and related compounds in the bulk drug was developed. The method resolves six known and several unknown impurities from the drug and each other using a nitrile column, a mobile phase composed of acetonitrile-sodium acetate buffer (35:65), and a UV detector set at 219 nm. Minimum quantifiable amounts of impurities are 0.02% or less relative to the drug. Ten lots of pindolol raw material were evaluated for purity and drug content. Total levels of impurities in these samples, quantitated against pindolol, ranged from about 0.03% to 0.24%.

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8

Kim, Jong-Soo. "Characteristics of humic substances and their removal behavior in water treatment." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/21469.

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9

Gude, Michael Thomas. "Critical properties of homologous series of substances." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/11205.

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10

Kumke, Michael U., and Fritz Hartmann Frimmel. "Stationary and time-resolved fluorescence for humic substances characterization." Universität Potsdam, 2002. http://opus.kobv.de/ubp/volltexte/2007/1235/.

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Steady-state and time-resolved fluorescence methods were applied to investigate the fluorescence properties of humic substances of different origins. Using standard 2D emission and total luminescence spectra, fluorescence maxima, the width of the fluorescence band and a relative fluorescence quantum efficiency were determined. Different trends for fulvic acids and humic acids were observed indicating differences in the heterogeneity of the sample fractions. The complexity of the fluorescence decay of humic substances is discussed and compared to simple model compounds. The effect of oxidation

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11

Baran, Ozlem. "Determination Of Narcotic And Psychotropic Substances By Using Infrared Spectroscopy." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606293/index.pdf.

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Narcotic and psychotropic substances are all chemicals that affect a person&rsquo<br>s mental activities, perceptual abilities, behavior and level of consciousness<br>they may cause physical and/or psychological dependence. For determination of narcotic and psychotropic substances, chromatographic techniques are usually preferred which are aimed to identify the target chemicals and require several extraction steps. In this study, an Infrared Spectrometric method has been developed for qualitative determination of most widely encountered substances (morphine, heroin, cocaine, MDMA (3,4-methylen

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12

Enlund, Anna Maria. "Capillary electroseparations in pharmaceutical analysis of basic drugs and related substances." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://w3.ub.uu.se/fulltext/91-554-4908-5.pdf.

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13

Scanlon, M. M. "Some aspects of the interaction of humic substances with metal ions." Thesis, Aston University, 1991. http://publications.aston.ac.uk/9783/.

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Humic substances are the major organic constituents of soils and sediments. They are heterogeneous, polyfunctional, polydisperse, macromolecular and have no accurately known chemical structure. Their interactions with radionuclides are particularly important since they provide leaching mechanisms from disposal sites. The central theme to this research is the interaction of heavy metal actinide analogues with humic materials. Studies described focus on selected aspects of the characteristics and properties of humic substances. Some novel approaches to experiments and data analysis are pursued.

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14

Moreno, Anjelica Victoria Peralez. "Modeling Atmospheric Transport of Perfluorinated Alkyl Substances from Chemours Facilities Using CALPUFF View." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555004834088189.

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15

Smith, Ian Derek. "Gas chromatographic studies into the stereoselective interactions of a modified cyclodextrin with enantiomeric substances." Thesis, Birkbeck (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287877.

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16

Shenderova, Anna. "The microclimate in poly(lactide-co-glycolide) microspheres and its effect on the stability of encapsulated substances /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488196234910341.

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17

Arogba, S. S. "The synthesis and analysis of antioxidants related to the natural phenolic lipids and similar substances." Thesis, Brunel University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304767.

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18

Lloyd, Frances Baird Wigton. "The viscosity of mixtures of substances in aqueous solution : What do we really know?" Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/26822.

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19

Armitage, James M. "Modeling the global fate and transport of perfluoroalkylated substances (PFAS)." Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8571.

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Perfluoroalkylated substances (PFAS) are persistent contaminants that are widely distributed in the global environment. Despite the fact that these chemicals have been manufactured and used for over 50 years, there has been little scientific and regulatory interest until very recently. An important research priority over the past decade has been to gain a better understanding of the mechanisms and pathways explaining the presence of these compounds in remote regions. One explanation is related to the use and release of volatile precursor compounds which undergo atmospheric transport and are al

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20

Hale, Kerry Anne. "The formation, synthesis and reactions of humic polymers in chemical and biological systems." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329937.

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21

Colomer, Vidal Pere. "Distribution of perfluoroalkyl substances in the environment." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/670952.

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Perfluoroalkyl substances (PFASs) are a large group of man-made chemicals that are widely used throughout society and found in the environment. These compounds are characterized by perfluorinated carbon chains of varying lengths with hydrophobic properties and containing an external polar and hydrophilic head. The difference between perfluoroalkyl sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs) are found on the polar head of the chemicals. In general, the characteristics of PFASs are based on the length of the perfluorinated carbon chain that they contain. As the number of perfluori

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22

Skerlj, Renato Tony. "Synthesis and chemistry of alkyl 2, 3-bis(trimethylstannyl)-2-alkenoates and related substances." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29391.

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This thesis describes the synthesis and chemistry of alkyl 2,3-bis(trimethylstannyl)-2-alkenoates ((78) and (83)). It was shown that these compounds could be readily transformed into useful intermediates for the synthesis of functionalized, stereochemically defined tetrasub-stituted alkenes (87) and tricyclic dienes of general structure (322A). The synthesis and chemistry of compounds (277) and (278) is also described. The palladium(O)-catalyzed addition of hexamethylditin to a variety of α,β-acetylenic esters (90), afforded in a stereoselective manner, the corresponding alkyl (Z)-2,3-bis(tr

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23

Kumke, Michael U., and Sascha Eidner. "Fluorescence and energy transfer processes of humic substances and related model compounds in terbium complexes." Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2007/1225/.

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The fluorescence properties and the fluorescence quenching by Tb3+ of substituted benzoic acid were investigated in solution at different pH. The substituted benzoic acids were used as simple model compounds for chromophores present in humic substances (HS). It is shown that the fluorescence properties of the model compounds resemble fluorescence of HS quite well. A major factor determining the fluorescence of model compounds are proton transfer reactions in the electronically excited state. It is intriguing that the fluorescence of the model compounds was almost not quenched by Tb3+ while the

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24

Kwon, Deokhyeon. "Optical and physicochemical properties of secondary organic aerosol and aerosol generated from humic substances." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6455.

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A great deal of attention has been paid to brown carbon aerosol in the troposphere because it can both scatter and absorb solar radiation, thus affecting the Earth’s climate. However, knowledge of the optical and chemical properties of brown carbon aerosol is still limited. In this thesis, we have investigated different aspects of the optical and physicochemical properties of various brown carbon aerosol samples of potential atmospheric importance. First, reactions involving the di-carbonyl species methylglyoxal (MG) have been previously suggested as an important pathway for the production of

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25

Gonzalez, Raymat Hansell. "Unrefined Humic Substances as a Potential Low-cost Remediation Method for Groundwater Contaminated with Uranium in Acidic Conditions." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3864.

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Anthropogenic activities such as uranium mining and milling, nuclear weapons production, and nuclear reprocessing have left a legacy of groundwater and soil contaminated with uranium that needs to be addressed. Therefore, developing new remediation technologies to sequester uranium in situ is crucial. The objective of the study was to determine if low-cost commercially available unrefined humic substances, such as Huma-K, can be used to facilitate uranium sorption to minerals in soil and sediment. Sediments from the saturated zone beneath the F-Area seepage basins at the Savannah River Site (S

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26

Emenike, Mary Elizabeth. "What is a Chemical? Fourth-Grade Children's Categorization of Everyday Objects and Substances." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1283196816.

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27

Amirkhani, Ardeshir. "Development of Techniques and Methods for the Quantitative Analysis of Endogenous Substances by Microcolumn Liquid Chromatography Coupled to Mass Spectrometry." Doctoral thesis, Uppsala University, Analytical Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3990.

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<p>Liquid chromatography-mass spectrometry (LC-MS) is a powerful technique for the analysis of endogenous compounds. The introduction of electrospray ionization (ESI) as an interface between LC and MS has contributed strongly to a trend towards miniaturization of LC, due to the possibility to perform ESI at low flow rates. In this thesis, several aspects regarding the design of miniaturized LC systems and electrospray emitters were investigated. In addition miniaturized LC-ESI-MS have been used for the qualitative and quantitative analysis of endogenous polar compounds, peptides and protein di

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28

Mulaudzi, Ludwig Vusimuzi. "Application of flow injection in the assay of selected substances in food and clinical analysis." Diss., Pretoria : [s.n.], 1999. http://upetd.up.ac.za/thesis/available/etd-11162006-163430/.

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29

Murrell, Ruth Dorothy. "The effects of non-ionic anaesthetic substances on voltage-activated and acetylcholine-activated ion channels." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293762.

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30

Seither, Joshua Zolton. "Application of High Resolution Mass Spectrometry for the Screening and Confirmation of Novel Psychoactive Substances." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3823.

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There has been an emergence of novel psychoactive substances (NPS) in forensic casework globally. Although the reported prevalence of these compounds has been relatively low in comparison to traditional drugs of abuse, published case studies suggest that some NPS have significant pharmacological effects that may cause severe impairment and/or death. Because of these effects, it is important that toxicology laboratories have the capability of identifying these compounds to complete a comprehensive toxicological analysis for human performance and post-mortem investigations. Recently, mass spectr

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31

Alessio, Rachael Josephine. "Removal of Bisphenol A Model Compounds and Related Substances Using Octolig®." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/3946.

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Bisphenol A used in the production of polycarbonate plastics and epoxy resins is ubiquitous in the environment. The raw material is released to the environment during the manufacturing process and by leaching from consumer products. Recent studies are suggesting that low-dose amounts of Bisphenol A may have adverse health effects on humans. The possibility of removing Bisphenol A from natural water sources or from solvents used to extract the material from consumer products before they enter the market has been studied. The use of model compounds and related substances (4-isopropylphenol, 4-(t

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32

Gwak, Seongshin. "Comprehensive Analysis of Emerging New Psychoactive Substances by Ion Mobility Spectrometry and Mass Spectrometry." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2291.

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In the new era of drug abuse, the proliferation of new psychoactive substances (NPS), commonly referred to as designer drugs or legal highs, has been a global concern. These substances are produced to circumvent current legislation for controlled substances with minor modifications in their chemical structure. Although many efforts have been made previously, the characterization of such substances are still challenging because of (1) the continual emergence of newly identified substances, (2) the lack of a universal screening test for NPS that are structurally similar to each other, and (3) th

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33

Eckberg, Melanie N. "Forensic Toxicological Screening and Confirmation of 800+ Novel Psychoactive Substances by LC-QTOF-MS and 2D-LC Analysis." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3923.

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Novel psychoactive substances (NPS) represent a great challenge to toxicologists due to the ability of illicit drug manufacturers to alter NPS chemical structures quickly and with ease to circumvent legislation regulating their use. Each time a new structure is introduced, there is a possibility that it has not been previously recorded in law enforcement or scientific databases. Many toxicology laboratories use targeted analytical methods that rely on libraries of known compounds to identify drugs in samples. However, these libraries do not include large numbers of NPS which could result in no

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34

Dalton, Rebecca Marie. "The development of students' mental models of chemical substances and processes at the molecular level /." View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20050721.160759/index.html.

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Thesis (Ph.D.) -- University of Western Sydney, 2003.<br>"A thesis submitted in fulfilment of the requirements for the award of the degree Doctor of Philosophy from University of Western Sydney" Bibliography : leaves 483-501.

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35

Dalton, Rebecca Marie, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "The development of students' mental models of chemical substances and processes at the molecular level." THESIS_CSTE_SFH_Dalton_R.xml, 2003. http://handle.uws.edu.au:8081/1959.7/816.

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The development of student’s mental models of chemical substances and processes at the molecular level was studied in a three-phase project. Animations produced in the VisChem project were used as an integral part of the chemistry instruction to help students develop their mental models. Phase one of the project involved examining the effectiveness of using animations to help first-year university chemistry students develop useful mental models of chemical phenomena. Phase two explored factors affecting the development of student’s mental models, analysing results in terms of a proposed model

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36

Ingvarsson, Sarah. "Characterization of hepatocyte derived metabolites of various New Psychoactive Substances using LC-QTOF-MS." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167499.

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New psychoactive substances are becoming increasingly common in many parts of the world, and some of them are marketed as “legal highs” and are produced to circumvent the drug legislation, and they come in many unregulated forms. The aim of this research was to characterize the metabolites of a new psychoactive substance and hence provide the fundamental data needed for further research of toxicity and future drug testing. The synthetic cannabinoid 4-fluoro-CUMYL-5-fluoro-PICA was incubated in cryopreserved hepatocytes for 1, 3 and 5 hour and then the formed metabolites was analyzed with an LC

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37

Davis, Christina Clarkson. "Aqueous Silica in the Environment: Effects on Iron Hydroxide Surface Chemistry and Implications for Natural and Engineered Systems." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/33948.

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Aqueous silica is present in all natural waters and exhibits a high affinity for the surfaces of iron oxides. Therefore, it is expected to play an important role in environmental systems. Experiments were conducted to investigate the fundamentals of silica sorption onto pre-formed ferric hydroxide at pH 5.0-9.5 and silica concentrations of 0-200 mg/L as SiO<sub>2</sub>. Over the entire pH range studied, sorption densities exceeding monolayer sorption were observed at silica levels typical of natural waters. Under some circumstances, sorption exceeded a monolayer while the particle zeta pot

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38

Chorier, Émilie. "Mise au point de méthodes d’analyse de substances critiques potentiellement présentes dans les produits et procédés de la filière cuir." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10046.

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Ce travail décrit la mise au point de onze nouvelles méthodes analytiques répondant aux exigences règlementaires REACh et à la protection des consommateurs. La première méthode permet de doser des substances dangereuses dans l’eau (RSDE) et en milieu polaire. Un protocole d’extraction unique du milieu aqueux qui permet de doser 75 substances prioritaires dans les eaux douces et résiduaires. Six méthodes instrumentales différentes sur des appareils aux caractéristiques diverses ont été associées pour obtenir des résultats beaucoup plus précis que ce qui se faisait auparavant et près des deux ti

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39

Graf, Phoebe [Verfasser], and Martin [Akademischer Betreuer] Dameris. "The impact of very short-lived substances on the stratospheric chemistry and interactions with the climate / Phoebe Graf ; Betreuer: Martin Dameris." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/113347893X/34.

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40

Da, Silva Pierre. "Une histoire de la recherche de substances naturelles à activités thérapeutiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-01038036.

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L'identification d'une substance naturelle, produite par un organisme vivant n'est que l'une des toutes premières étapes du développement d'un nouveau médicament. Beaucoup de molécules à visée thérapeutique développées par des sociétés pharmaceutiques ont en fait été découvertes dans des laboratoires académiques. C'est toujours un continuum de la recherche fondamentale vers la recherche appliquée, souvent de la recherche publique vers la recherche privée, qui aboutit à la mise au point d'un médicament. Leur fabrication, directement à partir de substances naturelles, pose fréquemment le problèm

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41

Liao, Jin. "Bromine and chlorine chemistry in the Arctic boundary layer." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45932.

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Halogen chemistry plays an important role in spring time ozone and mercury depletion events (ODEs and MDEs) and may efficiently oxidize hydrocarbons such as the important greenhouse gas methane (CH4) in the polar marine boundary layer. This thesis presents a detailed study of bromine and chlorine chemistry in the Arctic boundary layer based on measurements of bromine and chlorine containing species using chemical ionization mass spectrometry (CIMS). The capability of CIMS to accurately measure bromine oxide (BrO) was demonstrated. The first direct measurements of hypobromous acid (HOBr) were a

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42

Bevin, Anna, An Na Lay, Daniel Ullmark, and Jessika Hagman. "Chemical analysis of hazardous substances in permanent tattoo inks available on the market." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277104.

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As permanent tattoos are becoming more popular and common, an increased number of allergic reactions to tattoos is reported. The purpose of this project was to analyze tattoo inks for hazardous substances, and whether they comply to current Swedish and European legislative requirements. The tattoo inks were qualitatively analyzed for pigments, and quantitatively analyzed for metals. A total of 73 tattoo inks were collected from various sources such as a tattoo ink supplier, online retailers, and provided directly from tattoo artists. The labels of each tattoo ink bottle were inspected to inves

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43

Löfstrand, Karin. "Trends and exposure of naturally produced brominated substances in Baltic biota - with focus on OH-PBDEs, MeO-PBDEs and PBDDs." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-54421.

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The semi-enclosed and brackish Baltic Sea has become heavily polluted by nutrients, anthropogenic organic and inorganic chemicals via human activities. Persistent organic pollutants (POPs) have been thoroughly investigated due to their linkage to toxic effects observed in Baltic biota. There has been far less focus on semi-persistent pollutants e.g. naturally produced oraganohalogen compounds (NOCs) and their disturbances in the environment. This thesis is aimed on assessment of levels and trends of naturally produced brominated compounds in Baltic biota; more specifically on hydroxylated poly

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44

Kjellberg, Viktor. "Evaluation of a UPLC-MS method using 18O-labelled water for the identification of hydrolytic degradants of drug substances." Thesis, Uppsala universitet, Avdelningen för analytisk farmaceutisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257712.

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In this master’s thesis the hydrolytic degradation in 18O-water solutions of six drug substances has been studied. The aim was to develop a mass spectrometric method for easier identification of degradants, since hydrolysis in 18O-water will generate degradants with higher mass compared with hydrolysis in regular water. The degradation was carried out in both acidic and basic conditions. About 10 % degradation was aimed for in the study and the storage time and conditions were adjusted to accommodate that. The samples were then analyzed with UPLC-MS. Separation was achieved on either an Acquit

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45

Fabregat, Safont David. "Application of advanced mass spectrometric techniques for the identification, metabolic characterisation and toxicological analysis of new psychoactive substances." Doctoral thesis, Universitat Jaume I, 2020. http://dx.doi.org/10.6035/14104.2020.419068.

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This Doctoral Thesis presents an in-depth investigation on NPS from the analytical chemistry point of view, being structured in three blocks. The first is focused on the analytical characterisation of different compounds, as well as the development of novel analytical strategies for their determination. The second includes the application of different in vitro and in vivo models for assessing the metabolism, potency and pharmacokinetics properties of different NPS. Finally, the third presents an investigation about the use of NPS among teenagers. All the information presented in this Doctoral

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46

Ullberg, Malin. "Effects of pH and Cation Composition on Sorption of Per- and Polyfluoroalkyl Substances (PFASs) to Soil Particles." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256415.

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Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in the environment and to obtain detailed understanding of the transport processes, their partitioning beha

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47

Koriko, Moursalou. "Extraction, caractérisation, réactivité chimique des substances humiques naturelles avec les phosphates de Hahotoe-Kpogame et leurs propriétés photodégradantes." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2010. http://tel.archives-ouvertes.fr/tel-00719333.

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Les recherches de rendements agricoles de plus en plus élevés conduisent à l'utilisation des engrais chimiques et des produits phytosanitaires. L'utilisation non raisonnée de ces intrants agricoles a pour conséquences la pollution des sols, des eaux de surface et des eaux souterraines. Les recherches sur l'élaboration de nouveaux types de fertilisants écologiques et le devenir des polluants organiques dans l'environnement s'avèrent importantes. C'est dans ce cadre que se situe notre travail. La première étape de ce travail a été l'extraction et la caractérisation des substances humiques nature

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48

Kazi, Haseeb. "Plasma Interactions on Organosilicate Glass Dielectric Films and Emerging Amorphous Materials- Approach to Pore Sealing and Chemical Modifications." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801876/.

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In-situ x-ray photoemission (XPS) and ex-situ FTIR studies of nanoporous organosilicate glass (OSG) films point to the separate roles of radicals vs. VUV photons in the carbon abstraction. The studies indicate that reaction with O2 in presence of VUV photons (~123 nm) result in significant carbon abstraction within the bulk and that the kinetics of this process is diffusion-limited. In contrast, OSG exposed to atomic O (no VUV) results in Si-C bond scission and Si-O bond formation, but this process is self-limiting after formation of ~1 nm thick SiO2 surface layer that inhibits further diffusi

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49

Ahamada, Kadiria. "Stratégies biomimétiques en vue de la synthèse totale de deux substances naturelles polycycliques complexes : la bipléiophylline et l'haliclonine A." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA114807/document.

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Les travaux présentés concernent dans une première partie la synthèse biomimétique d’un alcaloïde indolomonoterpénique : la bipléiophylline. La bipléiophylline est le résultat de l’assemblage complexe de deux unités indoliques identiques ancrées sur une plateforme aromatique. Une stratégie générale de synthèse biomimétique de la bipléiophylline consistant i) à la synthèse de l’unité indolique pléiocarpamine et ii) à l’oxydation de l’acide 2,3-dihydroxybenzoïque a été envisagée. L’accès au squelette complexe de la pléiocarpamine a été étudié selon plusieurs stratégies de synthèse totale mais ég

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50

Yan, Lok-Hang. "Approche biomimétique des manadomanzamines et préparation d’analogues de la pelletiérine pour la synthèse biomimétique d’alcaloïdes de lycopodes." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA114812/document.

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Au cours de ce travail, nous nous sommes intéressés dans une première partie à la synthèse biomimétique d’alcaloïdes de type manzamines et plus particulièrement, aux manadomanzamines. Une étude de la réactivité des deux intermédiaires clés de leur biogenèse, les glutaconaldéhydes et les aminopentadiènals, a été entreprise. Ces mêmes molécules ont ensuite été utilisées comme équivalents synthétiques dans une synthèse biomimétique du squelette pentacyclique de la manadomanzamine A. Une seconde partie est consacrée à la préparation d’analogues stables de la pelletiérine en vue d’une synthèse biom

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