An investigation into chemical and biological assays of new compounds from aloes
- Authors: Mapp, R K
- Date: 1969
- Subjects: Medicinal plants -- Research -- South Africa , Botanical chemistry , Aloe -- Analysis , Aloe -- Research -- South Africa , Aloe , Aloin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3850 , http://hdl.handle.net/10962/d1012830
- Description: The drug aloes has been known since earliest times and is mentioned in the Ebers papyrus of circa 1,500 B.C. Alexander the Great is reported to have sent a commission to Socotra to investigate the aloes grown there. The chemical composition of aloes is complex, and being of plant origin, subject to variation. Both the complexity of the chemical constituents and their biological variation has resulted in a very large volume of conflicting material being published on this drug export. Since aloes is used as a purgative for both human and veterinary use, it is obviously important that the dosage and consequently the active constituents, should comply to an accurate means of standardisation. To date, despite extensive world wide research into this drug such standardisation has not been achieved. Even the methods used for the assay of the principal constituent, aloin, vary considerably in their results, and to complicate matters new chemical principles have been isolated from aloes in recent years. Consequently the purpose of this work has been to investigate the main chemical assay methods currently in use, and to determine which was the most accurate, and why discrepancies occurred in the selected assay methods. furthermore the results obtained by chemical assay have been compared with those obtained by biological assay in an attempt to correlate aloin content with purgative activity. Newly isolated compounds have been investigated biologically for the first time, and the biological assays of the resinous, glycosidal and other compounds of aloes have been performed. Intro. p.1-2.
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- Date Issued: 1969
An investigation into some aspects of Jovian decametric radiation
- Authors: Hill, I. E.
- Date: 1969
- Subjects: Jupiter (Planet) , Radiation , Magnetosphere
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5552 , http://hdl.handle.net/10962/d1015034
- Description: This thesis describes observations of the flne structure in Jovian decametric radiation made at Grahamstown during the 1967-68 apparition. It was found that pulses with duration less than 0.5 milliseconds were common during fine structure storms. The restrictions placed on the source for different theories of origin of the short pulses are discussed. The variation of the probability of occurrence from year to year is analysed on the assumption that the radiation is found in directions fixed with respect to the planet's magnetic field. It is concluded that there is a factor other than the declination of Earth and the Io effect which controls the probability of occurrence. A detailed analysis suggests a beam width of 3° in latitude at Jupiter but further work is necessary to check this.
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- Date Issued: 1969
An investigation into some aspects of the thin layer chromatographic assay of Pregnanediol with emphasis on the suitability of this method as a clinical laboratory routine
- Authors: Paton, L T
- Date: 1969
- Subjects: Thin layer chromatography , Pregnanediol
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3853 , http://hdl.handle.net/10962/d1013023
- Description: Pregnanediol (5B Pregnane- 3⋉- 20⋉- dial) is the chief urinary metabolite of progesterone, and as such is important in that variations in its concentration reflect variations in progesterone secretion. Estimations of pregnanediol concentration are therefore of considerable interest to the obstetrician and gynaecologist. Pregnanediol was first identified in the urine of pregnant women in 1929 by Marrian. Nearly ten years later Venning developed a method by which the glucuronic acid ester of pregnanediol could be extracted from the urine and its concentration gravimetrically determined. Numerous variations of the Venning theme were published in the next few years, each being claimed by its authors to be an improvement on the original. Most of these involved the estimation of the conjugated form, and it was a while before the advantage of estimating the hydrolysed aglycone was realized. Hydrolysis, when it was practised, resolved itself into two methods - namely, hydrolysis by heating the urine with a mineral acid, and enzymic hydrolysis by incubation with beta-glucuronidase. Acid hydrolysis, while producing a less clean hydrolysate, is more rapid and convenient than enzyme hydrolysis, and is used in the Klapper method which is presently the most widely used method in clinical studies. Klapper employs a double chromategraphic column separation of pregnanediol followed by colorimetric evaluation. Variations of Klapper's method have also appeared and not a few investigators have published comparisons of the various methods. Klapper himself compared his method to certain other methods and concluded that his was definitely superior. Of the accuracy of the Klapper method there is no doubt. Subsequent methods have proved more sensitive, but in terms of practicability Klapper's is the method of choice. As was pointed out with some complacency, "practicability is most satisfactory, one technician readily performing some twenty determinations in one week." In contrast to the flood of criticisms, comparisons, variations, claims and counter-claims which accompanied the publication of the abovementioned methods, the thin layer chromatographic method perfected by Waldi attracted very little attention. It is very much more rapid than all other existing techniques, is very sensitive, specific and of acceptable accuracy. In an attempt to ensure its usefulness for clinical and medical research laboratories, the Waldi method has been marketed in 'kit' form. It is intended primarily as a diagnostic aid in establishing pregnancy, and as such it might have enjoyed considerable application had it not been for the advent of the immunological method of pregnancy diagnosis which is very much more rapid. Nevertheless, the Waldi method, used purely as a means of assessing the pregnanediol content of the urine is extremely useful, and it is the purpose of this investigation to establish this usefulness, especially with respect to routine clinical investigations. The validity of some diagnoses which are based on pregnanediol assay results, is also investigated. As it is impossible to explain the significance or usefulness of a pregnanediol assay without first explaining the functions of progesterone, some time and space must be expended in a brief description, firstly, of the role played by progesterone in the phenomenon of the menstrual cycle, and secondly, of its vital importance in pregnancy. It must be realized that progesterone is only one of the many hormones involved in these events, but, in order to limit the introduction of extraneous detail, no mention is made of the other hormonal participants except when necessary for the understanding of the whole. It may be mentioned here that much of the evidence that was used for the elucidation of the functions and origins of progesterone, was derived from studies of its metabolite, pregnanediol.
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- Date Issued: 1969
Aspects of the ecology of piscivorous birds of Lake Kyle Rhodesia
- Authors: Junor, F J R
- Date: 1969
- Subjects: Bird populations -- Zimbabwe , Water birds -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5909 , http://hdl.handle.net/10962/d1015201
- Description: [From Introduction]. From an early period in the lake's history research was undataken to determine the potential of Kyle as a source of edible fish, In such a study, knowledge of the number and weight of fish consumed by piscivorous birds would seem to be an obvious consideration. Accordingly special investigation was undertaken into the food requirements of fish eating birds which live in the lake area. The method employed, on this occasion, to obtain the required information has differed radically from that more generally used by investigators working with similar objects in view. The common practise has been to examine the stomach contents of a considerable number of birds of the same species, which have been destroyed in order to make information available.
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- Date Issued: 1969
Novel components of Acacia mearnsii
- Authors: Ilsley, Anthony Hugh
- Date: 1969
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:21164 , http://hdl.handle.net/10962/6673
- Description: From Summary: From the complex mixture of flavonoid components present in the heartwood of the black wattle tree (Acacia mearnsii) four new compounds have been isolated. These include a novel dioxane-linked dimeric proanthocyanidin based on leucofisetinidin. This is the first proanthocyanidin of its type to be isolated from a natural source. I solation was achieved by standard counter current partition separation and preparative paper chromatographic techniques. The compound, which forms an anthocyanidin, was identified by micro-degradation, and n.m.r. and mass spectrometry. Comparison of the spin-spin coupling constants of the heterocylic rings' protons with those of authentic monomeric flavan-3, 4-diols showed that the heterocyclic rings of the two symmetrical flavan moeities have 2,3-trans-3,4-cis configurations. Dreiding models suggest that the central dioxane ring has a half-boat conformation while the heterocyclic rings of the two flavan units have five point coplanar conformations. Two possible absolute configurations have been proposed
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- Date Issued: 1969
Ray tracing at very low frequencies when the effects of heavy ions are considered
- Authors: Terry, Patrick D.
- Date: 1969
- Subjects: Ionospheric radio wave propagation , Ionosphere -- Graphic methods , Ray tracing algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5542 , http://hdl.handle.net/10962/d1013350
- Description: The behaviour of very low frequency (V.L.F.) radio waves propagating in an ionlzed medium, such as the ionosphere and exosphere, may exhibit markedly different characteristics from those of frequencies such as are used for communication in the short-wave bands. The anisotropy introduced into the medium by the presence of the earth's magnetic field has a significant effect, while at frequencies below about 5KHz the presence of heavy positive ions may further affect propagation. In particular it is found that, under suitable conditions, V.L.F. signals may propagate along paths closely following the lines of force of the earth's magnetic field. The study of such signals has a practical interest in that, from consideration of their propagation times and dispersion properties, they can provide an inexpensive method of determining electron densities at well beyond the range of satellite investigation. For this reason, if for no other, theoretical investigation of the paths traced in a model exosphere may indicate how closely the model exosphere approximates the true one. A powerful method of tracing out these paths is by the use of "ray-tracing", provided the properties of the medium vary slowly in space, a condition not always fulfilled in practice. It has been the subject of this thesis to carry out ray-tracing studies, in particular noting the effects of the positive ions in the exosphere; effects which have not received much notice before as they were thought to be unimportant. Intro., p. 1-2.
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- Date Issued: 1969
Static and ultrasonic elastic moduli of wool, mohair and kemp fibres
- Authors: King, Neville Edwin
- Date: 1969
- Subjects: Moduli theory , Mohair , Wool
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5528 , http://hdl.handle.net/10962/d1012640 , Moduli theory , Mohair , Wool
- Description: Fibres used in textiles can be classified broadly into natural fibres and synthetic fibres. Natural fibres can be either animal, such as wool, mohair and camel hair, or vegetable such as cotton, flax and hemp. In the development of synthetic fibres numerous polymers have emerged which have no real natural counterpart and are unique in their mechanical and chemical behaviour. Often the synthetic counterpart of a natural fibre has properties with certain advantages from the textile point of view, but, simultaneously, may exhibit other properties which have disadvantages. Nylon 6 and nylon 6-6, for exemple, are extremely strong and generally easier to dye than animal fibres. On the other hand, they absorb relatively little water vapour and therefore do not give the buffering action characteristic of hygroscopic fibres, once they are woven or knitted into cloth. All textile fibres belong to the chemical class of polymers, i.e. they are made up of repeating molecular units which are linked together to form long chains. In wool the chains are made up of amino-acids which cluster together to form protein chains. Three of these protein chains, coil around each other to form what is termed a proto-fibril. The proto-fibrils make up the micro-fibrils, each of these consisting of eleven of the three chain proto-fibrils. The micro-fibrils, in turn, pack together in bundles which run parallel to the length of the wool fibre and are termed macro-fibrils. Sulphur rich amino-acids fill up the spaces between the micro-fibrils forming a matrix which binds the system into a continuous material. Intro., p. 1.
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- Date Issued: 1969
Studies on the ecology and systematics of the diatoms (Bacillariophyta) from some South Africa rivers
- Authors: Archibald, Robert Eldred Mostert
- Date: 1969
- Subjects: Diatoms -- Ecology -- South Africa , Diatoms -- Classification , Aquatic ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4098 , http://hdl.handle.net/10962/d1009494 , Diatoms -- Ecology -- South Africa , Diatoms -- Classification , Aquatic ecology -- South Africa
- Description: This report contains the results of some ecological and systematic studies on the diatoms from the Vaal Dam catchment area in the Transvaal, and the Bloukrans River in the Eastern Cape Province. In Part 1 the effects of high concentrations of nitrogen were studied in relation to the composition of the diatom associations. Water samples from four stations on the Bloukrans River were analysed chemically at certain intervals during the months of April and August 1967. Diatom samples collected from these stations at the beginning and end of each of these sampling periods were subjected to a "Thomasson Analysis" to determine the relative densities of the various species in the diatom associations. A statistical analysis of the results reflected a poor but positive correlation between the two variables, i.e. high numbers of nitrogen heterotrophic Nitzschiae were correlated with high concentrations of nitrogen, while low numbers were correlated with low concentrations. Part 2 presents the results of the ecological studies on the diatom associations of the Vaal Dam Catchment Area. In this section the diatom associations from each sampling point or station were subjected to a "Thomasson Analysis" to determine the relative densities of the different species in the associations. Employing already known correlations between environment and association, the results of this analysis were discussed and the ecological conditions for each sampling station were assessed. The associations were similar in composition over the entire catchment area, and indicated on the whole water of good quality. Points of pollution were detected, but were generally localised and the effects of the pollution were soon removed. Only the Waterval River showed evidence of more constant pollution. The associations provided evidence for some seasonal variation in their composition. Finally in Part 3 the systematics and taxonomy of the diatoms in the Vaal Dam catchment area are discussed. References are made to the original and more recent descriptions of each species found in this study, and a list of synonyms is given wherever 'possible. Comments on the systematics, taxonomy and autecology of each species are given, and the distribution of the species in South Africa and the Vaal Dam catchment area is discussed. A number of species, varieties and forms have been recorded for the first time in South Africa. During the course of this study 20 species have been described as new to science; the descriptions of some have been published, while the descriptions of the others will be published formally in the future. All species described as new or having interesting features are illustrated in the plates.
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- Date Issued: 1969
The amphibolite at Chibuluma Mine Zambia
- Authors: Thomson, Iain Dennis
- Date: 1969
- Subjects: Amphibolite -- Zambia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5066 , http://hdl.handle.net/10962/d1013391
- Description: Chibuluma Mine is situated on the southern flank of the Nkana-Chambishi basin in the central section of the Zambian Copperbelt. The amphibolite at Chibuluma Mine occurs exclusively in the Upper Roan Group sediments overlying the economically important Lower Roan Group. The amphibolite occurs in lenticular, sill-like bodies ranging in thickness from less than 10 feet to over 1,000 feet. It is concluded that these sill-like bodies are intrusive sills of basic magma. The largest sill is a multiple intrusion with two phases, both of which exhibit chilled margins. The younger phase was intruded into the older along a plane approximately 50 feet above its basal contact. Grainsize, specific gravity, and micrometric data indicate that each phase of the intrusion has undergone gravitational differentiation during crystallisation. Variations in the relative amounts of amphibole and feldspar distinguish between a lower melanocratic amphibolite, an upper mesotype amphibolite, and a zone of coarse-grained pegmatitic amphibolite schlieren. The amphibolite consists mainly of hornblende, labradorite, albite, and scapolite, with accessory biotite, chlorite, epidote, clinozoisite, sphene, apatite, quartz, micropegmatite, and calcite. Clouding of the basic plagioclase and zoning in amphibole, plagioclase, and scapolite are features of petrological significance. The opaque minerals in the amphibolites and the adjacent sediments are magnetite, ilmenite, pyrite, chalcopyrite, pyrrhotite, cubanite, valleriite, and pentlandite. Intergrowths of these suggest that their temperatures of formation were probably in excess of 450°C. The chemical data show a close resemblance between the amphibolite and a tholeiitic magma-type although minor spilitic characteristics are also evident. The chemical data also confirm the mineralogical evidence of fractionation and gravitational differentiation. The trend in differentiation followed in the development of the pegmatitic and mesotype amphibolite is very similar to the trends followed by other basic intrusions. The main metamorphic affect accompanying the intrusion of the amphibolite is the soda metasomatism evident in both sediments and intrusions. Some evidence exists to suggest that the amphibolites were emplaced before or during the early stages of the Lufilian orogeny when sediments were essentially horizontal.
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- Date Issued: 1969
The geology of a portion of north-western Albany
- Authors: Wright, Alexander Ross
- Date: 1969
- Subjects: Geology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5068 , http://hdl.handle.net/10962/d1013440
- Description: [Introduction] During 1965 the author, in looking for a project for a thesis to be submitted for the degree of Master of Science in Geology, decided to map a suitable region in order to gain experience in geological field work. The exact nature of the region itself was of no great importance, but since this study was to be conducted through Rhodes University, it was decided that an area, as near to Grahamstown as possible, would be the most suitable. With this in view, the geologist in charge of the Grahamstown Office of the Geological Survey was invited to suggest an area suitable for study, and if possible, to obtain financial assistance. He indicated the region which has been mapped and which will eventually form part of the proposed sheet 143. It is immediately adjacent to, and to the west of the 1:125,000 sheet 136 of Grahamstown completed by Mountain in 1940.
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- Date Issued: 1969
The Patchway Gold Mine : a mineragraphic and petrographic examination of ore from the Patchway Gold Mine, Rhodesia, and an appraisal of the relationship between gold mineralisation and geological structure
- Authors: Ward, J H W
- Date: 1969
- Subjects: Gold ores -- Geology -- Zimbabwe , Petrology -- Zimbabwe , Geology -- Zimbabwe , Ores -- Zimbabwe , Gold mines and mining -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5069 , http://hdl.handle.net/10962/d1013471
- Description: A remarkable correlation between hydrothermal gold mineralisation and geological structure is discussed. The mineralisation occurs in vein quartz which occupies a fissure in Archaean greenstones of the Basement Complex in Rhodesia, It has been determined that gold which is silver-rich is typical of low-grade ore, and is associated in space with sulphides that crystallised early in paragenesis. Silver-poor gold is characteristic of highgrade ore which is concentrated along the crestal zone of anticlinal warps in the fissure. It is suggested that the local pattern of fracturing and folding is related to fundamental wrench faulting.
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- Date Issued: 1969