In dié studie is sekere aspekte van voedingswaarde van droogtebestandegewasse, tussen twee seisoene en op drie verskillende lokaliteite nl Hatfield, Mier en Lovedale, geondersoek. Die spesies wat met mekaar vergelyk is, was: C. sturtii, A. nummularia, A. halimus A. canescens(Santa Rita), A. canescens (Veldreservaat 1), en A. canescens(Rincon). Die twee seisoene was herfs en winter. Uit dié resultate kan die volgende afleiding gemaak word:betekenisvolle(P < 0.05) laer blaar-totstamverhouding gedurende die winter as die herfs kon by die onderskeie proefpersele van, C. sturtii en A. canescens (Veld 1)(Hatfield); A. canescens(Veld 1) en A. canescens(Rincon)(Mier); A. canescens(Veld 1) en A. canescens(Santa Rita)(Lovedale), waargeneem word. In teenstelling met die bogenoemde bevindinge het A. nummularia(Lovedale) betekenisvol (P < 0.05) hoër blaar-totstamverhouding in die winter as die herfs gehad. Vir A. canescens (Santa Rita) het die Mier proefperseel betekenisvolle (P < 0.05) hoër blaar-tot-stamverhouding as die ander twee lokaliteite getoon. By al drie proefpersele, vir alle spesies, is die blaar RP % sowel as die IVDMV % van die blare betekenisvol (P < 0.05) hoër as dié van stamme. Vir al die spesies geoes by Mier, was die NBV % in die winter betekenisvol (P < 0.05) hoër as in die herfs. C. sturtii (Lovedale) het geen betekenisvolle (P > 0.05) verskille in die chemiese samestelling tussen seisoene getoon nie, terwyl die ander spesies wel betekenisvolle (P < 0.05) verskille getoon het. Slegs in die geval van A. nummularia kon betekenisvolle (P < 0.05) verskille in IVDMV % tussen lokaliteite waargeneem word. Indien die tempo van degradasie (c) gedurende die herfs by Hatfield geoes, tussen spesies vergelyk word, het A. canescens (Veld 1)betekenisvolle (P < 0.05) hoër c-waarde as dié vanaf A. nummularia en A.canescens (Santa Rita) gehad. Slegs monsters op Hatfield gedurende die herfs geoes kon betekenisvolle (P < 0.05) verskille in PD tussen A. canescens (Veld1) en A. nummularia waargeneem word. Slegs by Mier, in die herfs, het A. nummularia betekenisvol(P < 0.05) hoër ED as A. canescens (Veld 1) gehad. Vir wintermonsters kon geen betekenisvolle (P > 0.05) verskille in die c-waarde tussen spesies en lokaliteite waargeneem word nie. Wintermonsters, geneem te Mier, het A. canescens (Veld 1) betekenisvol (P < 0.05) laer PD as die ander spesies gehad, terwyl by Lovedale het A. canescens(Santa Rita) betekenisvol (P < 0.05) laer PD as die ander spesies gehad. A. nummularia het betekenisvol (P < 0.05) hoër ED as die ander spesies, by Mier en Lovedale, vir monsters wat gedurende winter geoes is, gehad. Wanneer gasproduksiewaardes tussen spesies vergelyk word, het A. canescens (Veld 1) betekenisvol (P < 0.05) minder gas as die ander spesies, vir inkubasie tye 20,30 en 44 ure, geproduseer. Betekenisvolle (P < 0.05) verskille in die a-waarde kon tussen die hoë C. sturtii en die lae A. canescens. (Santa Rita), maar nie tussen die ander spesies, waargeneem word. Betekenisvollen (P < 0.05) verskille in die b-waarde kon tussen: C. sturtii (145.1 ml/g DM), A. canescens (Veld 1)(127.9 ml/g DM)en A. canescens (Rincon)(164.9 ml/g DM) waargeneem word. Betekenisvolle verskille (P < 0.05) in die tempo van gasproduksie kon net tussen die hoë C. sturtii (0.086/h) en die lae A. canescens (Santa Rita)(0.065/h) waargeneem word. Betekenisvolle (P < 0.05) verskille in die potensiële gasproduksie (a + b) kon tussen: C. sturtii, A. canescens. (Veld 1) en A. canescens (Rincon) waargeneem word. Droogtebestande gewasse kan as medium tot lae kwaliteit voerbronne beskou word,wat op strategiese tye(droogte tye) benut kan word. ENGLISH : The nutritive value of four drought tolerant crops were investigated at three localities during two seasons. The species which have been compared, were C. sturtii, A. nummularia, A. halimus, A. canescens (Santa Rita), A. canescens (Field reserve 1), and (Rincon). The two seasons were autumn and winter. A significantly (P < 0.05) lower leaf-to-stem ratio was recorded for the species <i<C. sturtii and A. canescens (Field 1) at Hatfield, while at Mier A. canescens (Field 1) and A. canescens (Rincon) were found to have significant (P < 0.05)lower values in the winter than in the autumn. At Lovedale, the winter leaf-to-stem ratios were significantly (P < 0.05) lower than in the autumn for A. canescens (Field 1) and A. canescens (Santa Rita). In contrast to the above, A. nummularia had a significantly (P < 0.05) higher leaf-to-stem ratio in winter than in autumn at Lovedale. Overall, A. canescens (Santa Rita) harvested at Mier had a significantly (P < 0.05) higher leaf-to-stem ratio than material from the other two sites. At all the sampling sites and for all accessions the CP % and the IVDMD % of the leaves were significantly (P < 0.05) higher than those of the stems. The NDF % in most of the species harvested during winter, was significantly (P < 0.05) higher than those harvested during autumn. C. sturtii was the only species for which no significant (P > 0.05) differences in the chemical composition could be found between the two seasons. Only in the case of A. nummularia could significant (P < 0.05) differences in the IVDMD % be found between localities. A. canescens (Field 1) harvested during autumn at Hatfield, had a significantly higher rate of passage(c) than A. nummularia and A. canescens (Santa Rita). Samples harvested at Hatfield in autumn also produced significant (P < 0.05) differences in PD between A. canescens (Field 1) and A .nummularia. Mier was the only sampling site where significantly (P < 0.05) higher (A. nummualaria) and lower (A. canescens(Field1)) ED were observed for samples taken during autumn. No significant (P > 0.05) differences in the rate of passage (c) were observed between species or sampling sites for samples taken during the winter. Winter samples taken from A. canescens (Field 1) at Mier and A. canescens (Santa Rita) taken from Lovedale, showed significantly (P < 0.05) lower PD than the other species. A. nummularia had significantly (P < 0.05) higher ED than the other species harvested at Mier and Lovedale, during winter. When gas production values between species were compared it was clear that A. canescens (Field1) produced significantly (P < 0.05) less gas compared to the other species at incubation times of 20, 30 and 44 hours. Significant (P < 0.05) differences in the a-values were also observed between the high C. sturtii and the low A. canescens (Santa Rita) values. Significant (P < 0.05) differences in the b-value were observed between C. sturtii (145.1ml/g DM), A. canescens (Field 1)(127.9 ml/g DM) and A. canescens (Rincon)(164ml/g DM). C. sturtii (0.086/h) and A. canescens (Santa Rita)(0.065/h) were the only species that differed significantly (P < 0.05) in terms of the rate of passage(c). Significant (P < 0.05) differences in the potential gas production (a + b) were observed between C.sturtii, A. canescens (Field 1) and A. canescens (Rincon). Drought resistant crops can be considered as a medium to low quality source of fodder which can be used at strategic times, especially during periods of drought. Copyright / Dissertation (MScAgric)--University of Pretoria, 2010. / Animal and Wildlife Sciences / unrestricted

Malaria is currently a huge treat worldwide, as far as infections are concerned, and is responsible for thousands of deaths per annum. The dilemma associated with the development of anti–malarial drug resistance over the past few decades should be addressed as a matter of urgency. Novel drug delivery systems should be developed in order to employ new and existing anti–malarial drugs in the treatment and management of malaria. The aim of these delivery systems should include an improvement in the efficacy, specificity, acceptability and therapeutic index of anti–malarial drugs. Previous studies have suggested that liposomes have the ability to encapsulate, protect and to promote the sustained release of anti–malarial drugs. Two liposome formulations, namely liposomes and chloroquine entrapped in liposomes, were formulated during this thesis and evaluated by conducting a stability study and an in vitro study with the main focus on cell viability. The stability study consisted of a series of stability tests regarding the stability of nine liposome and nine chloroquine entrapped in liposome formulations over a period of twelve weeks. The in vitro study included three assays such as a reactive oxygen species assay, a lipid peroxidation assay and a hemolysis assay. The aims of these studies included the manufacturing of liposomes, the incorporation of chloroquine into liposomes, the determination of the stability of the formulations as well as the evaluation of the possible in vitro toxicity of liposomes. Results obtained from these studies revealed that liposomes remained more stable over the stability study period in comparison to chloroquine entrapped in liposomes. The entrapment of chloroquine within liposomes was possible, although the initial entrapment efficiency (%) of 14.55 % was much too low. The production of reactive oxygen species occurred to a small extent in the red blood cells and the infected red blood cells. Equal amounts of reactive oxygen species (%) was observed within both the red blood cells and the infected red blood cells with a maximum value of 23.27 % in the presence of the chloroquine entrapped in liposomes at varying concentrations. Red blood cells experienced the highest degree of lipid peroxidation (%) in the presence of chloroquine, at varying concentrations, entrapped in liposomes. The maximum amount of lipid peroxidation (%) was 79.61 %. No significant degree of hemolysis (%) was observed in the red blood cells neither in the presence of the liposomes nor in the presence of the chloroquine entrapped in liposomes at varying concentrations. It can be concluded that liposomes are a more stable formulation and have less toxic effects on red blood cells and infected red blood cells in comparison to the chloroquine entrapped in liposome formulations. Future studies should investigate the possibility of a more stable and less toxic chloroquine entrapped in liposome formulation. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2011.

Malaria is a curable disease that claims nearly one million lives each year. Problems with the treatment of malaria arise as resistance spreads and new treatment options are becoming less effective. The need for new treatments are of the utmost importance. Liposomes combined with antimalarials are a new avenue for research as liposomes can increase the efficacy of drugs against pathogens, as well as decreasing toxicity. Amodiaquine is a drug with known toxicity issues, but has proven to be effective and is, therefore, a prime candidate to be incorporated into the liposomal drug delivery system. The aim of this study was to prepare, characterize and evaluate the toxicity of the liposomes with incorporated amodiaquine. The solubility of amodiaquine was determined and liposomes formulated with, and without, amodiaquine entrapped. Accelerated stability studies (at 5 'C, 25 'C with relative humidity of 60% and 40 'C with a relative humidity of 40%) were conducted during which the size, pH, morphology and the entrapment efficacy was determined. The toxicity was determined in vitro by analysing the levels of reactive oxidative species and lipid peroxidation caused by the formulations to erythrocytes infected with P. falciparum as well as uninfected erythrocytes with flow cytometry. The solubility study of amodiaquine in different pH buffers showed that amodiaquine was more soluble at lower pH values. Solubility in solution with pH 4.5 was 36.3359 ± 0.7904mg/ml when compared to the solubility at pH 6.8, which was 15.6052 ± 1.1126 mg/ml. A buffer with a pH of 6 was used to ensure adequate solubility and acceptable compatibility with cells. Liposomes with incorporated amodiaquine were formulated with entrapment efficacies starting at 29.038 ± 2.599% and increasing to 51.914 ± 1.683%. The accelerated stability studies showed the median sizes and span values remained constant for both liposome and amodiaquine incorporated liposomes at 5 'C. The higher temperatures, i.e. 25 'C and 40 'C, displayed increases in the median size, and decreases in the span for both formulations. The conclusion can, therefore, be made that both liposome and amodiaquine incorporated liposomes are stable at lower temperatures. The entrapment efficacy increased from initial values to nearly 100% during the course of the stability study. This was attributed to amodiaquine precipitating from the solution. The pH values of the liposomes and amodiaquine incorporated liposomes remained constant for each formulation; though the amodiaquine incorporated liposomes had a lower starting pH, the formulations are both thought to be stable in terms of the pH. Toxicity studies revealed low levels of reactive oxygen species as well as low levels of lipid peroxidation for both liposome and amodiaquine incorporated liposomes, on both erythrocyte and Plasmodium infected erythrocytes. From the toxicity studies it can be concluded that liposomes and amodiaquine incorporated liposomes are not toxic to erythrocytes and infected erythrocytes. It was concluded that liposomes incorporating amodiaquine could possibly be used as a treatment option for malaria. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2011.

Malaria is currently a huge treat worldwide, as far as infections are concerned, and is responsible for thousands of deaths per annum. The dilemma associated with the development of anti–malarial drug resistance over the past few decades should be addressed as a matter of urgency. Novel drug delivery systems should be developed in order to employ new and existing anti–malarial drugs in the treatment and management of malaria. The aim of these delivery systems should include an improvement in the efficacy, specificity, acceptability and therapeutic index of anti–malarial drugs. Previous studies have suggested that liposomes have the ability to encapsulate, protect and to promote the sustained release of anti–malarial drugs. Two liposome formulations, namely liposomes and chloroquine entrapped in liposomes, were formulated during this thesis and evaluated by conducting a stability study and an in vitro study with the main focus on cell viability. The stability study consisted of a series of stability tests regarding the stability of nine liposome and nine chloroquine entrapped in liposome formulations over a period of twelve weeks. The in vitro study included three assays such as a reactive oxygen species assay, a lipid peroxidation assay and a hemolysis assay. The aims of these studies included the manufacturing of liposomes, the incorporation of chloroquine into liposomes, the determination of the stability of the formulations as well as the evaluation of the possible in vitro toxicity of liposomes. Results obtained from these studies revealed that liposomes remained more stable over the stability study period in comparison to chloroquine entrapped in liposomes. The entrapment of chloroquine within liposomes was possible, although the initial entrapment efficiency (%) of 14.55 % was much too low. The production of reactive oxygen species occurred to a small extent in the red blood cells and the infected red blood cells. Equal amounts of reactive oxygen species (%) was observed within both the red blood cells and the infected red blood cells with a maximum value of 23.27 % in the presence of the chloroquine entrapped in liposomes at varying concentrations. Red blood cells experienced the highest degree of lipid peroxidation (%) in the presence of chloroquine, at varying concentrations, entrapped in liposomes. The maximum amount of lipid peroxidation (%) was 79.61 %. No significant degree of hemolysis (%) was observed in the red blood cells neither in the presence of the liposomes nor in the presence of the chloroquine entrapped in liposomes at varying concentrations. It can be concluded that liposomes are a more stable formulation and have less toxic effects on red blood cells and infected red blood cells in comparison to the chloroquine entrapped in liposome formulations. Future studies should investigate the possibility of a more stable and less toxic chloroquine entrapped in liposome formulation. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2011.

Malaria is a curable disease that claims nearly one million lives each year. Problems with the treatment of malaria arise as resistance spreads and new treatment options are becoming less effective. The need for new treatments are of the utmost importance. Liposomes combined with antimalarials are a new avenue for research as liposomes can increase the efficacy of drugs against pathogens, as well as decreasing toxicity. Amodiaquine is a drug with known toxicity issues, but has proven to be effective and is, therefore, a prime candidate to be incorporated into the liposomal drug delivery system. The aim of this study was to prepare, characterize and evaluate the toxicity of the liposomes with incorporated amodiaquine. The solubility of amodiaquine was determined and liposomes formulated with, and without, amodiaquine entrapped. Accelerated stability studies (at 5 'C, 25 'C with relative humidity of 60% and 40 'C with a relative humidity of 40%) were conducted during which the size, pH, morphology and the entrapment efficacy was determined. The toxicity was determined in vitro by analysing the levels of reactive oxidative species and lipid peroxidation caused by the formulations to erythrocytes infected with P. falciparum as well as uninfected erythrocytes with flow cytometry. The solubility study of amodiaquine in different pH buffers showed that amodiaquine was more soluble at lower pH values. Solubility in solution with pH 4.5 was 36.3359 ± 0.7904mg/ml when compared to the solubility at pH 6.8, which was 15.6052 ± 1.1126 mg/ml. A buffer with a pH of 6 was used to ensure adequate solubility and acceptable compatibility with cells. Liposomes with incorporated amodiaquine were formulated with entrapment efficacies starting at 29.038 ± 2.599% and increasing to 51.914 ± 1.683%. The accelerated stability studies showed the median sizes and span values remained constant for both liposome and amodiaquine incorporated liposomes at 5 'C. The higher temperatures, i.e. 25 'C and 40 'C, displayed increases in the median size, and decreases in the span for both formulations. The conclusion can, therefore, be made that both liposome and amodiaquine incorporated liposomes are stable at lower temperatures. The entrapment efficacy increased from initial values to nearly 100% during the course of the stability study. This was attributed to amodiaquine precipitating from the solution. The pH values of the liposomes and amodiaquine incorporated liposomes remained constant for each formulation; though the amodiaquine incorporated liposomes had a lower starting pH, the formulations are both thought to be stable in terms of the pH. Toxicity studies revealed low levels of reactive oxygen species as well as low levels of lipid peroxidation for both liposome and amodiaquine incorporated liposomes, on both erythrocyte and Plasmodium infected erythrocytes. From the toxicity studies it can be concluded that liposomes and amodiaquine incorporated liposomes are not toxic to erythrocytes and infected erythrocytes. It was concluded that liposomes incorporating amodiaquine could possibly be used as a treatment option for malaria. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2011.

Plant-feeding mites represent major pests in agriculture that are of importance to crops world-wide, as large populations of mites reduce the quality and quantity of yields. Alternatives to the use of pesticides are needed due to their negative effects and bio-control agents (predatory mites) remain advantages as they suppress spider mites and other plant pests. This study aims to determine species status of plant-feeding and predatory mites on plants of the family Solanaceae and to apply morphological and molecular data to determine phylogenetic relationships among economically important Phytoseiidae, Stigmaeidae and Tetranychidae. The material for this study was collected through plant beating and specimens were preserved in 75% and 96% ethanol respectively and mounted in Heinz’s PVA medium on microscope slides. A survey was conducted during peak seasons to provide enough samples of pest and predatory species. Morphological analysis was performed and initial results indicate that 94% of the species identified were parasitic and 6% were predatory, which led to a predator:prey ratio of 1:17, where Tetranychus evansi Baker & Pritchard had the highest frequency of appearance. A modified Qiagen DNeasy tissue kit extraction protocol was used and Polymerase Chain Reaction was performed to amplify ribosomal ITS and mitochondrial COI gene fragments. The nucleotide sequence of a 700-bp fragment for ITS was determined by direct sequencing as well as for a 700-bp and 800-bp fragments for COI. The resulting data included 4 isolates that corresponded morphologically and molecularly with Phytoseiidae and 10 with Stigmaeidae. The phylogenetic trees agreed with the morphological data. For species that lack morphological descriptions in GenBank and are not placed within expected clades, one has to accept the possibility of miss identification and highlights the need to combine morphological and molecular approaches to guarantee solid species diagnosis. Ultimately, Solanaceae contain various parasitic mites, but predators seem low in numbers. This could be problamatic in finding effective bio-control agents. / MSc (Zoology), North-West University, Potchefstroom Campus, 2015

Plant-feeding mites represent major pests in agriculture that are of importance to crops world-wide, as large populations of mites reduce the quality and quantity of yields. Alternatives to the use of pesticides are needed due to their negative effects and bio-control agents (predatory mites) remain advantages as they suppress spider mites and other plant pests. This study aims to determine species status of plant-feeding and predatory mites on plants of the family Solanaceae and to apply morphological and molecular data to determine phylogenetic relationships among economically important Phytoseiidae, Stigmaeidae and Tetranychidae. The material for this study was collected through plant beating and specimens were preserved in 75% and 96% ethanol respectively and mounted in Heinz’s PVA medium on microscope slides. A survey was conducted during peak seasons to provide enough samples of pest and predatory species. Morphological analysis was performed and initial results indicate that 94% of the species identified were parasitic and 6% were predatory, which led to a predator:prey ratio of 1:17, where Tetranychus evansi Baker & Pritchard had the highest frequency of appearance. A modified Qiagen DNeasy tissue kit extraction protocol was used and Polymerase Chain Reaction was performed to amplify ribosomal ITS and mitochondrial COI gene fragments. The nucleotide sequence of a 700-bp fragment for ITS was determined by direct sequencing as well as for a 700-bp and 800-bp fragments for COI. The resulting data included 4 isolates that corresponded morphologically and molecularly with Phytoseiidae and 10 with Stigmaeidae. The phylogenetic trees agreed with the morphological data. For species that lack morphological descriptions in GenBank and are not placed within expected clades, one has to accept the possibility of miss identification and highlights the need to combine morphological and molecular approaches to guarantee solid species diagnosis. Ultimately, Solanaceae contain various parasitic mites, but predators seem low in numbers. This could be problamatic in finding effective bio-control agents. / MSc (Zoology), North-West University, Potchefstroom Campus, 2015

Occupational risk management can be a catalyst in generating superior returns for all stakeholders on a sustainable basis. A number of companies in South Africa have implemented Cardinal Rules of Safety adopted from international companies to ensure the safety of their employees. The purpose of this study was to measure the impact of the cardinal rules on employee safety behaviour implemented at power stations in Mpumalanga. The empirical study was done by using a questionnaire as measuring instrument. The questionnaire was developed from a literature review and contains questions and items relevant to the initial research problem. The questionnaire comprised of five–point Likert scale type questions.The convenience sampling method was applied identifying 90 participants at three different power stations in Mpumalanga taking part in the study. Statistical analysis was performed by the Statistical Consulting Service of the North–West University using SPSS. Cronbach’s alpha co–efficients was used to determine the reliability of the factors. Descriptive statistics (Mean, standard, deviation, were used in the compiling of the profile of the results. While Spearman’s rho correlation coefficient was calculated to identify practically significant associations between variables and factors The research findings suggest that there is practical significant correlation between the factors that were measured. The opinion given by respondents suggests that cardinal rules of safety were implemented, given all the necessary support by management and enforced throughout the organisation. / Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2012.

Occupational risk management can be a catalyst in generating superior returns for all stakeholders on a sustainable basis. A number of companies in South Africa have implemented Cardinal Rules of Safety adopted from international companies to ensure the safety of their employees. The purpose of this study was to measure the impact of the cardinal rules on employee safety behaviour implemented at power stations in Mpumalanga. The empirical study was done by using a questionnaire as measuring instrument. The questionnaire was developed from a literature review and contains questions and items relevant to the initial research problem. The questionnaire comprised of five–point Likert scale type questions.The convenience sampling method was applied identifying 90 participants at three different power stations in Mpumalanga taking part in the study. Statistical analysis was performed by the Statistical Consulting Service of the North–West University using SPSS. Cronbach’s alpha co–efficients was used to determine the reliability of the factors. Descriptive statistics (Mean, standard, deviation, were used in the compiling of the profile of the results. While Spearman’s rho correlation coefficient was calculated to identify practically significant associations between variables and factors The research findings suggest that there is practical significant correlation between the factors that were measured. The opinion given by respondents suggests that cardinal rules of safety were implemented, given all the necessary support by management and enforced throughout the organisation. / Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2012.

科学研究費補助金 研究種目:一般研究(B) 課題番号:06453174 研究代表者:川岸 舜朗 研究期間:1994-1995年度