No description available.

Increases in the expression of prostaglandin E2 (PGE2) are widely known to be involved in aberrant growth in the early stage of colon cancer development. We herein demonstrated that the novel indole compound MW-03 reduced PGE2-induced cAMP formation by catalization to an inactive metabolite by inducing 15-hydroxyprostaglandin dehydrogenase through the activation of peroxisome proliferator-activated receptor-γ. MW-03 also inhibited colon cancer cell growth by arresting the cell cycle at the S phase. Although the target of MW-03 for cell cycle inhibition has not yet been identified, these dual anti-cancer effects of MW-03 itself and/or its leading compound(s) on colon cancer cells may reduce colon cancer development and, thus, have potential as a novel treatment for the early stage of this disease.

Magister Scientiae - MSc / Apoptosis is a process in which a cell programmes its own death. It is a highly organized physiological mechanism in which injured or damaged cells are destroyed. Apart from physiological stimuli however, exogenous factors can induce apoptosis. Many anti-cancer drugs work by activating apoptosis in cancer cells. Natural substances have been found to have the ability to induce apoptosis in various tumour cells and these substances have been used as templates for the construction of novel lead compounds in anticancer treatment. On the other hand, alkylating agents such as cisplatin, cis- [PtCl2 (NH3) 2] have been widely used as antineoplastic agents for a wide variety of cancers including testicular, ovarian, neck and head cancers, amongst others. However, the use of cisplatin as an anticancer agent is limited due to toxicity and resistance problems. The aim of this present study was to screen the leaves of Rhus laevigata, a South African indigenous plant, for the presence of pro-apoptotic and anti-proliferative natural compounds and also to screen newly synthesised palladium based complexes (15 and 57) and a platinum based complex (58) for their antineoplastic activities tested against a panel of cell lines. Results. The results showed that crude methanol extracts from Rhus laevigata as well as the newly synthesised palladium based complexes (15 and 57) and a platinum based complex (58) induced apoptosis in the cell lines tested, as demonstrated by the externalization of phosphatidylserine, mitochondrial membrane permeabilization, caspase-3 activation, and DNA fragmentation. Caski (cervical cancer) and H157 (non small cell lung carcinoma) cell lines treated with the methanol extract from Rhus laevigata however, were more resistant to apoptosis induction. Among the metallocomplexes, complexes 15 and 57, palladium based complexes, were the most active. Conclusion The methanol extract from the leaves of Rhus laevigata contain pro-apoptotic and antiproliferative natural compound(s), which need to be characterised and elucidated as they could provide the much-needed lead compounds in the fight against cancer. On the other hand the newly synthesized palladium complexes also need further evaluation to see if they can be used as anticancer agents that can overcome the problems associated with cisplatin.

(in English): The aim of this thesis is to describe the functioning of French compound infinitive in comparison with its simple form. Using language corpora, we will cover several textual types - journalism (corpus L'Est Républicain and a part of InterCorp corpus), fiction (corpus InterCorp), but we will also utilize typologically various texts from the Internet (corpus frWac) and a corpus of film subtitles. The theoretical part will describe the infinitives forms in terms of terminology, morphology, and syntax. The empirical part will be dedicated to mapping out the contexts in which the compound infinitive occurs and also to analyzing different factors that affect its aspectual and temporal interpretation. In conclusion, there is a summary as well as possible issues for further research dealing with this topic.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14634号 / 工博第3102号 / 新制||工||1461(附属図書館) / 26986 / UT51-2009-D346 / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 大塚 浩二, 教授 木村 俊作, 教授 松原 誠二郎 / 学位規則第4条第1項該当

Abstract In this work a manometric respirometric measuring system was applied to practical environmental cases related to wastewater management and biodegradation studies of oil-contaminated soils and materials used in landfill structures. Pollution of groundwater, surface water and soils is a worldwide problem. Therefore, tests simulating the biodegradation behaviour of organic compounds in water media and soils have become increasingly important. Respirometric methods provide direct measurement of the oxygen consumed by micro-organisms in biodegradation processes from an air or oxygen-enriched environment in a closed vessel. Biochemical oxygen demand (BOD) is a crucial environmental parameter used to measure the quality of water and treatment results in wastewater. Generally, BOD is measured with standardised methods, which are usually time-consuming as well as laborious. In this work the manometric respirometric test was compared with conventional BOD tests by determining the BOD of pulp and paper mills as well as domestic wastewater samples. The effect of different factors such as type, amount and pre-treatment of inoculum and the effect of dilution of a sample on the BOD values were also tested. A right dilution was noticed to be the most significant factor affecting the BOD values of the industrial wastewater samples. The mathematic estimation of the BOD7 values from the respirometric data was proved to work reliably after a 2–3 day incubation period. Characterisation of organic fractions of the pulp and paper mill wastewater was carried out with methods including filtration, long term BOD measurements and COD analyses. The most significant observation in characterisation analyses was that a remarkable part of the detected oxygen demand was consumed for the biotransformation of biodegradable fractions into new inert decomposition products, not only for mineralisation of the biodegradable COD fraction. Biodegradation behaviour of the peat samples with different decomposition rates was studied in order to evaluate the applicable peat types that can be used in landfill structures. Only minor (BOD/ThOD < 0.4%) biodegradation was observed with compaction peat samples, and the stable state, in which biodegradation stopped, was achieved during a two month period. The manometric respirometric method was also applied for the biodegradation studies in which the effect of the modification of soil properties on biodegradation rates of bio-oils was tested. Modified properties were the nutrient content and the pH of the soil. Fertiliser addition and pH adjustment increased both the BOD/ThOD% values of the model substances and the precision of the measurement. The manometric respirometric method was proved to be an advanced method for simulating biodegradation processes in soil and water media.

An experiment was conducted to determine the effects of shade netting on growth, oil yield and compound composition of fever tea (Lippia javaica). The treatments were nine shade nets of different light intensities (100% bird net, 40% green, 10, 12 and 18% white and 30, 40, 55 and 70% black). The layout used was a completely randomized design. The parameters measured were shoot width, fresh shoot mass, the number of plants flowered, plant height and photosynthetically active radiation. Shade netting did not have any effect on the shoot width of L. javanica. Eighteen percent white net was best suited to produce fresh shoot mass, whereas 55% black net, 40% black net and 10% white net produced lower fresh shoot mass. More plants that flowered were obtained under 70% black net than those grown under 30% black net. The number of plants that flowered increased from 22 to 35 with an increase in shading density. The height of plants was not affected by shade netting at 49 DAT. However, at 59 and 67 DAT, the height of the plants was greater under low light intensities (40, 55, and 70% black nets) than that of high light intensity (30% black). Twelve percent white net had the greatest plant height at 102 DAT. Shade netting significantly affected the adsorption and utilization of photosynthetically active radiation (PAR) above, across and below the plants at 102 DAT. Hundred percent bird net had the greatest amount of light intercepted above, across and below the plants. The amount of light intercepted above, below and across the plants was lower for lower shading intensity (30% black) than that of higher shading intensities (40%, 55% and 70% black). To determine shade-netting effect on oil yield and compound composition, fresh leaves (± 200g) of L. javanica were sampled from each shade net for essential oil extraction by hydrodistillation. The oil yield ranged from 0.29% to 0.41%. The oil had a clear to yellowish brown colour. No significant differences were detected for oil yield amongst the shade nets. The chemical compound analysis was carried out by GC/MS. The chemical compounds identified in the essential oil were <font face="symbol">a</font>-pinene, sebinen, myrcene, 1.8 myrcene, ipsenone, ipsedienone, <font face="symbol">b</font>-caryophyllen and germacrene-D. L. javanica plants grown under 10% white net, resulted in significantly higher myrcene content (15.7%) as compared to plants grown in other shade nets. Shade netting did not have any effect on the composition of á-pinene, sebinene, 1.8 myrcene, ipsenone, ipsedienone, <font face="symbol">b</font>-caryophyllen and germacrene-D. For commercial usage of myrcene, white net (10%) would be best suited for L. javanica production. To obtain information about indigenous knowledge of L. javanica, a survey was carried out among street traders, traditional healers, hawkers and farmers in Gauteng. The age group was between 20 and 73. The majority of respondents, who were self employed, were traditional healers followed by farmers. Most (98%) of the respondents indicated that they collected L. javanica from the veld by cutting the plant, whereas other respondents uprooted the whole plant when harvesting. Amongst the different uses of L. javanica mentioned, treatment of colds and coughs through steaming was stated by most (47%) of the respondents. Most (88%) of the respondents felt that it was important to conserve the plant for future generations and also to prevent the plant from becoming extinct. Traditional healers knew the uses and other important aspects of L. javanica than the farmers. / Dissertation (M Inst Agrar (Agronomy))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

No description available.

Magister Scientiae - MSc / Background and objectives: Apoptosis is a process in which a cell programmes its own death. It is a highly organized physiological mechanism in which injured or damaged cells are destroyed. Apart from physiological stimuli however, exogenous factors can induce apoptosis. Many anti-cancer drugs work by activating apoptosis in cancer cells. Natural substances have been found to have the ability to induce apoptosis in various tumour cells and these substances have been used as templates for the construction of novel lead compounds in anticancer treatment. On the other hand, alkylating agents such as cisplatin, cis- [PtCl2 (NH3) 2] have been widely used as antineoplastic agents for a wide variety of cancers including testicular, ovarian, neck and head cancers, amongst others. However, the use of cisplatin as an anticancer agent is limited due to toxicity and resistance problems. The aim of this present study was to screen the leaves of Rhus laevigata, a South African indigenous plant, for the presence of pro-apoptotic and anti-proliferative natural compounds and also to screen newly synthesised palladium based complexes (15 and 57) and a platinum based complex (58) for their antineoplastic activities tested against a panel of cell lines. Results. The results showed that crude methanol extracts from Rhus laevigata as well as the newly synthesised palladium based complexes (15 and 57) and a platinum based complex (58) induced apoptosis in the cell lines tested, as demonstrated by the externalization of phosphatidylserine, mitochondrial membrane permeabilization,caspase-3 activation, and DNA fragmentation. Caski (cervical cancer) and H157 (non small cell lung carcinoma) cell lines treated with the methanol extract from Rhus laevigata however, were more resistant to apoptosis induction. Among the metallocomplexes, complexes 15 and 57, palladium based complexes, were the most active. Conclusion: The methanol extract from the leaves of Rhus laevigata contain pro-apoptotic and antiproliferative natural compound(s), which need to be characterised and elucidated as they could provide the much-needed lead compounds in the fight against cancer. On the other hand the newly synthesized palladium complexes also need further evaluation to see if they can be used as anticancer agents that can overcome the problems associated with cisplatin. / South Africa

Fedmis Pty (Ltd) situated in Palaborwa, South Africa produces phosphoric acid using the wet process production process. For this study, two main areas of concern in the wet process phosphoric acid production were investigated. The first area is the formation of sludge in the system due to impurities that reduces the grade of the acid produced, thereby lowering the selling price. The second area is the crystallisation of the gypsum that influences filtration and thereby affects plant productivity. These two aspects were investigated separately as they occur in different steps of the production process at different acid concentrations. A major component of the acid sludge is known as x-compound, ((Fe,Al)3KH)14 (PO4)8.4H2O). The purpose of the investigation of x-compound is to determine what effects different ionic impurities have on its precipitation and to determine if these effects could be used to decrease the amount of sludge formation. Due to the complexity of the system and the wide variety of impurities only the major impurities were considered in this study. These impurities included potassium (K+), sodium (Na+), magnesium (Mg2+), aluminium (Al3+) and iron (Fe3+). For all the experiments investigating the effect of impurities, analytical reagents were used on laboratory scale. For the silica experiments, commercially available samples were used. For the experiments investigating the impurity effects on the precipitation of x-compound it was found that: <ul> <li> Agitation increases x-compound precipitation and can be used commercially to increase the precipitation rate to a point where sludge can be removed before transportation.</li> <li> Adding x-compound seeding crystals or magnesium ions also increases precipitation.</li> <li> Adding gypsum, sodium, hexafluorosilicates or fluorosilic acid reduces the precipitation, with sodium ions producing the lowest yield. This reduction is however not sufficient to be used commercially.</li> </ul> From the Raman study it became clear why x-compound precipitation is such a slow process. E At low acid concentrations, more H2PO4 - ions are present that form a complex with iron and aluminium. E As the acid concentration increases the concentration of H2PO4- ions decrease as the degree of dissociation of phosphoric acid decreases. The ferric- H2PO4- and aluminium- H2PO4- complexes become less stable and ultimately precipitation of the x-compound is favoured above solvation. E Addition of potassium impurities to the solutions had no visible effect on the Raman spectra and is suspected not to form a complex with the acid. From the silica sources investigated namely Dicalite, Serina Kaolin, Foskor silica and Aerosil 200 it can be concluded that none of the sources will be useful for the removal of potassium through formation of potassium hexafluorosilicates. For the determination of the concentration of impurities present in the production of phosphoric acid, the Fedmis monitoring program was initiated. It included the monitoring of Foskor rock analyses on a daily basis, and the monitoring of the 27%, 39% and 54% P2O5 phosphoric acid and precipitate, from these acid solutions on a weekly basis. From the investigation of the effect of these impurities on the solubility of potassium hexafluorosilicates, it was found that magnesium causes K2SiF6 to be the most soluble and fluoride the least. Unfortunately, the impurities did not help to reduce the potassium concentrations in the acid to below the required amount for sludge formation. For the calcium sulphate dihydrate surfactant experiments, the purpose of the investigation was to determine whether higher crystallisation qualities could be obtained to improve plant productivity. The investigation was limited to using surfactants with sulphate or phosphate functionalities and experiments were done on laboratory scale using analytical reagents. Atphos E3205, Atpol E3202 and Atpol E1231 are polyethoxylated alkyl phenol phosphate esters that had no visible effect on the crystal structure of the precipitated gypsum, but differences in the crystal sizes were observed. Smaller crystal structures with relatively equal masses compared to reference experiments are an indication of a growth inhibitor and a nucleation promoter as seen with Atphos E3205 and Atpol E3202. Increased crystal sizes were obtained using Atpol E1231. The use of Calsoline Oil caused a wider crystal size distribution in the precipitated crystals as thin and broad crystals with approximately the same length are found. The crystal mass obtained is also approximately the same as that of the reference experiment. Thus, it can be concluded that the surfactant affects the growth of the crystals and not the nucleation. Arlatone 1489, calcium gluconate monohydrate, Dowfax Hydrotrope and Tamol NN 8906 had no visible effect on the structure or size of the precipitated gypsum crystals. With the use of Nansa SS30, drastic effects were seen on the crystallisation of the calcium sulphate as small hexagonal rods were found. With an increase in surfactant concentration, there is a clear decrease in the mass of crystals obtained as well as crystal size. An increase in the crystal size distribution and a decrease in crystal size reduced the filtration rate dramatically. Experiments carried out for 24 hours exhibited the same trends where there is a decrease in yield with an increase in surfactant concentration. Higher yields were however obtained proving that mass transfer barriers were overcome. The results from these experiments again indicate that the surfactant affects crystal growth and nucleation. With the use of Dowfax 3B2 there is definite reduction in yield with an increase in surfactant concentration reaching a minimum at approximately 70% yield. Due to the presence of large amounts of smaller crystals and the almost constant yield obtained compared to the reference experiment, it can be concluded that this surfactant is a growth and not a nucleation inhibitor. As with Nansa SS30, experiments where Empicol LZ/D was used show a continuous decrease in the yield obtained with an increase in the surfactant concentration. At higher concentration of Empicol LZ/D, it seems as if this surfactant changed from a growth promoter to a growth inhibitor because although broad longer crystals are present, there are now also much smaller crystals formed. The crystal size distribution also broadens considerably. Overall, very high yields were obtained using Empimin KSN70 and the observed crystal size distributions were very narrow. The only difference was that the crystals appeared to be more porous or fibrous compared to the reference experiment. It is recommended that the experiments showing promise as crystal habit modifiers like Nansa SS30 and Empicol LZ/D be investigated in more detail as well as combinations of surfactants. Both the areas of concern in the process were investigated successfully. For the sludge formation problem, it is now clear what effects the precipitation of x-compound as well as what affect the impurities and operating conditions have. For the crystallisation of gypsum using surfactants, it was proven that surfactants could be used to affect crystal growth, shape and distribution and in this way influence filtration. / Dissertation (MSc(Chemical Engineering))--University of Pretoria, 2005. / Chemical Engineering / unrestricted