Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 1589 for “"substances"”.
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Development of a test system for screening toxic substances: a comparison using organic substances
… was to develop a test system for screening toxic substances by predicting their aquatic ecosystem effects. The system studied was a static, one liter microcosm with a diverse species assemblage. Teh microcosm was composed of biotic inoculum, chemically defined medium and sediment. The biotic …
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Humic Substances Removal by Activated Carbon
… peat were used to evaluate the removal of humic substances by various activated carbons. Different analytical methods were investigated to determine humic substances as possible indicators of chloroform formation potential. Total organic carbon measurement and ultraviolet/visible absorbance …
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The characterization of humic substances in seawater
Humic substances were isolated in gram quantities from seawater by a newly developed procedure of adsorption on a crosslinked polystyrene-divinylbenzene resin. The chemical and physical characteristics of both humic acid and fulvic acid fractions were studied. The elemental composition, the …
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Young people’s perceptions of novel psychoactive substances
Novel Psychoactive Substances (NPS) also known as “legal highs” replicate the effects of illegal substances such as ecstasy and cocaine. The most common NPS reported are stimulants and synthetic cannabinoids. Despite the Psychoactive Ban (2016) recent reports identified the UK as having the largest …
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Emotional Cutoff In Women Who Abuse Substances
… in this clinical sample of women who abused substances than in two comparison samples - one was a non-clinical sample of women balancing multiple roles and responsibilities and one mixed sample of divorced men and women. Emotional cutoff was found to have a significant positive relationship …
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Synthèse et biosynthèse de substances défensives d'insectes
… intéressés à la synthèse et à la biosynthèse de substances défensives d’insectes et, plus particulièrement, aux alcaloïdes de coccinelles. Afin d’en déterminer la configuration absolue, nous avons, dans un premier temps, entrepris la synthèse énantiosélective de la calvine et de la 2-épicalvine, …
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The characterization of humic substances in seawater
Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences.
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The vasodilatory and antioxidant activities of polyphenolic substances
This project was designed to determine the effect of a wide range of grape and tea based extracts and green tea catechins on vascular tension in vitro, further determine the relationship between their vasodilatory and antioxidant activities and identify the major polyphenols present in green and …
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Critically discussing the trends surrounding novel psychoactive substances.
Novel psychoactive substances (NPS), previously known as ‘legal highs’, have been common in the UK for many years (EMCDDA, 2018). The aim of this research work was to combine spectroscopic analysis with review of literature to assess the trends arising from the use of novel psychoactive substances …
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Separation and Structure Characterization of Biologically Important Substances
An attempt was made to isolate urease inhibitors from commercial Yucca schidigera extract. Trans-3,3$\sp\prime$,5,5$\sp\prime$- tetrahydroxy-4-methoxystilbene was isolated and its structure was assigned. Biological tests indicated that it was a urease inhibitor, and that it was also active against …
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New routes to enantioenriched substances through small organic molecules
In this thesis we will disclose the results obtained from the diastereoisomeric salt formation (n salt, p salt and p1,n1 salt) between non-racemic trans-chrysanthemic acid (trans-ChA) and pure enantiomers of threo-2-dimethylamino-1-phenyl-1,3-propanediol (DMPP). The occurrence of p1,n1 salt …
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