This study is aimed at investigating the feasibility of using the radiometric technique as an alternative to traditional methods for determining soil physico-chemical parameters which are important for terroir characterization. In-situ and ex-situ radiometric analyses of soil from three vineyard blocks of Simonsig Wine Estate in the Stellenbosch district (Western Cape, South Africa) were studied. A mobile MEDUSA gamma-ray detection system comprising a CsI(Na) crystal (length 15 cm, diameter 7 cm) and associated electronics mounted on a portable trolley were used for partial terroir characterisation. Thereafter activity concentrations of 40K, 232Th series and 238U series in soil (top ~30 cm) from the measured MEDUSA spectra (0 – 3 MeV) were extracted by means of the full-spectrum analysis (FSA) method. A lead-shielded HPGe detector was used for analyzing collected soil samples while soil physico-chemical parameters were analysed using standard methods at research and commercial laboratories.

The polychlorinated biphenyls (PCBs) comprise a group of 209 congeners varying in the number of chlorine atoms and substitution patterns. These compounds tend to be biomagnified in foodwebs and have been shown to induce an array of effects in exposed organisms. The structural characteristics of the PCBs influence their potency as well as mechanism of action. In order to assess the biological potency of these compounds a multi-step quantitative structure-activity relationship (QSAR) procedure was used in the project described in this thesis. The ultraviolet absorption (UV) spectra were measured for all 209 PCBs, and digitised for use as physico-chemical descriptors. Interpretations of the spectra using principal component analysis (PCA) showed the number of ortho chlorine atoms and para-para substitution patterns to be significant. Additional physico-chemical descriptors were derived from semi-empirical calculations. These included various molecular energies, the ionisation potential, electron affinity, dipole moments, and the internal barrier of rotation. The internal barrier of rotation was especially useful for describing the conformation of the PCBs on a continuous scale. In total 52 physico-chemical descriptors were compiled and analysed by PCA for the tetra- to hepta-chlorinated congeners. The structural variation within these compounds was condensed into four principal properties derived from a PCA for use as design variables in a statistical design to select congeners representative for these homologue-groups. The 20 selected PCBs have been applied to study structure-specific biochemical responses in a number of bioassays, and to study the biomagnification of the PCBs in various fish species. QSARs were established using partial least squares projections to latent structures (PLS) for the PCBs potency to inhibit intercellular communication, activate respiratory burst, inhibit dopamine uptake in synaptic vesicles, compete with estradiol for binding to estrogen receptors, and induce cytochrome P4501A (CYP1A) related activities. By the systematic use of the designed set of PCBs the biological potency was screened over the chemical domain of the class of compounds. Further, sub-regions of highly potent PCBs were identified for each response measured. For risk assessment of the PCBs potency to induce dioxin-like activities the predicted induction potencies (PIPs) were calculated. In addition, two sets of PCBs were presented that specifically represent congeners of environmental relevance in combination with predicted potency to induce estrogenic and CYP1A related activities.

The structure of 11S cruciferin has been solved; however, how the individual subunits contribute to its physico-chemical and functional properties are not well known. The cruciferin isoforms in Arabidopsis thaliana, CRUA, CRUB, and CRUC, were investigated with respect to their molecular structures and the relationship of structural features to the physico-chemical and functional properties of cruciferin using homology modeling and various analytical techniques. Comparison of these models revealed that hydrophobicity and electrostatic potential distribution on the surface of the CRUC homotrimer had more favorable interfacial, solubility, and thermal properties than those of CRUA or CRUB. Flavor binding and pepsin digestion were associated with hypervariable regions (HVRs) and center core regions, respectively, moreso for CRUA and CRUB homotrimers than for CRUC. Chemical imaging of a single cell area in wild type (WT) and double-knockout seeds (CRUAbc, CRUaBc, and CRUabC) using synchrotron FT-IR microscopy (amide I band, 1650 cm-1, νC=O) showed that seed storage proteins were concentrated in the cell center and protein storage vacuoles, whereas lipids were closer to the cell wall. Secondary structure components of proteins of double-knockout lines did not show major differences. Changes in protein secondary structure components of pepsin-treated CRUabC (CRUC) mutant were minimal, indicating low enzyme accessibility. A three-step chromatographic procedure allowed isolation of the hexameric form of cruciferin with high purity (>95%). Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopic analysis of the secondary structure of these proteins revealed cruciferins were folded into higher order secondary structures; 44−50% β-sheets and 7−9% α-helices. The relative subunit ratio was approximately 1:3:6 (CRUA:CRUB:CRUC) in the WT cruciferin. The Tm values of purified cruciferin at pH 7.4 (μ = 0.0) were in the order of WT = CRUA = CRUB < CRUC. The order of surface hydrophobicity as determined by ANS (1-anilinonaphthalene-8-sulfonate) probe binding was CRUA > CRUB = WT >> CRUC. Intrinsic fluorescence studies revealed a compact molecular structure for the CRUC homohexamer compared to the CRUA and CRUB homohexamers. The order of emulsion forming abilities was CRUA = CRUB > WT > CRUC (no emulsion formation) and the order of heat-induced network structure strength was WT > CRUA = CRUB > CRUC (no gel formation). The inability of CRUC to form gels or emulsions may be attributed to its low surface hydrophobicity and molecular compactness. At pH 2.0, CRUC hexamers dissociated into trimers which allowed the formation of an O/W emulsion and heat-induced network structures. Solubility of cruciferin as a function of pH at low ionic strength gave two minima around pH 4 and 7.4 yielding a “W” shape solubility profile deviating from the typical “U” or “V” shape solubility profile of other 11S globulins. The high ionic strength (μ = 0.5) was not favorable for emulsification, heat-induced gel formation, or solubilization for all cruciferins. Furthermore, the CRUA and CRUB homohexamers exhibited rapid pepsinolysis, while the CRUC homohexamer and WT heterohexamer were digested more slowly. Although fairly well conserved regions were found in the primary structure of these three cruciferin subunits, differences were found in the hypervariable regions and extended loop regions resulting in slight differences in 3D structures and interactions that occur during association to form superstructures, such as hexamers. These differences were reflected in the physico-chemical and techno-functional properties of hexamers and trimers composed of each subunit. In silico predictions for certain functionalities were highly correlated with empirical data from laboratory experiments.

Berry ripening in lowbush blueberry (Vaccinium angustifolium Ait.) is influenced by developmental, physiological and climatic factors resulting in a heterogenous mix of maturities at harvest. This study characterizes the physico-chemical changes which occur during fruit ontogeny and links ripening patterns to micoclimate. Individual clones in five commercial fiels were followed in the 2006 and 2007 growing seasons. Phenolic acids, flavonols, and flavan-3-ols decreased and anthocyanins increased with maturity. Peak maturity consistently occurred at 1200 accumulated growing degree days (GDD). There was a sharp decline in fruit retention at the end of the growing season suggesting a date after which harvested yield declines but no consistent pattern was detected between years or fields.The consistency of GDD accumulation in relation to ripening pattern suggests GDDs can be used as a predictive ripening index. The physico-chemical nature of ripe berries indicates ripe berries could be harvested earlier than is currently the practice.

No description available.

This study is aimed at investigating the feasibility of using the radiometric technique as an alternative to traditional methods for determining soil physico-chemical parameters which are important for terroir characterization. In-situ and ex-situ radiometric analyses of soil from three vineyard blocks of Simonsig Wine Estate in the Stellenbosch district (Western Cape, South Africa) were studied. A mobile MEDUSA gamma-ray detection system comprising a CsI(Na) crystal (length 15 cm, diameter 7 cm) and associated electronics mounted on a portable trolley were used for partial terroir characterisation. Thereafter activity concentrations of 40K, 232Th series and 238U series in soil (top ~30 cm) from the measured MEDUSA spectra (0 – 3 MeV) were extracted by means of the full-spectrum analysis (FSA) method. A lead-shielded HPGe detector was used for analyzing collected soil samples while soil physico-chemical parameters were analysed using standard methods at research and commercial laboratories.

A multi-integrative approach was used to identify spatial and temporal relationships of natural and anthropogenic environmental variables affecting riverine ecosystem structure and function in the Athabasca Oil Sands Region (AOSR). A series of inter-related field studies were conducted to assess three key components of the freshwater food web (physico-chemical environment, basal productivity, benthic macroinvertebrates) utilizing an a priori environmental disturbance gradient experimental design. The gradient design was formulated to best discriminate the possible effects of natural and anthropogenic environmental variables on two river basins (Steepbank and Ells Rivers) each having different levels of oil sands (OS) land use disturbance. Findings from this study showed that natural variation explained most longitudinal and seasonal responses of physico-chemical environmental variables for both rivers, including possible mechanisms such as physical and chemical effects from the OS geological deposit and inputs from shallow groundwater upwelling. Basal productivity was likely controlled by natural variables within the Steepbank and Ells Rivers, such as potential OS deposit effects, nutrient availability and influences from turbidity and physical factors, with disturbance from OS development either negligible or not detected. Longitudinal and seasonal differences in benthic macroinvertebrate community composition were mostly related to natural variation, including possible mechanisms such as high discharge and sediment slump events on the Steepbank River, and community shifts from elevated metal concentrations from natural sources at upstream sites on the Ells River. This study demonstrated that developing baseline information on watersheds can be essential at discriminating sources of disturbance, with natural variation potentially confounding with anthropogenic factors. This study also highlights the need for further research to obtain an improved understanding of mechanistic pathways to better determine natural and anthropogenic non-point source disturbances and cumulative effects on the structure and function of tributary ecosystems in the AOSR at relevant spatial and temporal scales. / Graduate / 0329 / clsuzann@uvic.ca

Water quality in the Vaalharts region in the Northern Cape Province, South Africa, decreased over the past few years and there was a need for the microbiological and physico-chemical assessment. This problem was identified through discussions with Vaalharts Water (Vaalharts Water User Association) in 2010 when the issue of the impact of deteriorating water quality on drinking water production was raised. It was thus important to investigate concerns of the water users association pertaining to water quality issues. The aim of this study was to assess the physico-chemical and microbiological quality of household water in the Vaalharts irrigation scheme. The main residential areas were Hartswater, Pampierstad, Jan Kempdorp and Warrenton. Faecal coliforms were detected in the raw water of all the drinking water distribution systems during 2011 and 2012. No faecal coliforms were detected in the household water during 2011. This was a very positive result, because not only did the household water comply with the SANS 241 (2011) standard (0 CFU/100ml), but the purification processes were successful by removing all the E. coli’s from the raw water. However, during March 2012 faecal coliforms were detected in the household water of Jan Kempdorp (191CFU/100ml). This could be due to point pollution and possible breakage of faecal coliforms in the distribution system. Low amounts of total coliforms were detected in the raw water of some of the drinking water distribution systems. This could be due to high amounts of other colonies (pink and purple) growing on the m-Endo agar which suppress the growth of the metallic green sheen (total coliform) colonies. The total coliform numbers complied with the SANS 241 (2011) standard of ≤10 CFU/100ml at most of the distribution systems, except for Hartswater during July 2011 (14CFU/100ml) and Warrenton during March 2012 (256 CFU/100ml). Heterotrophic plate count bacteria were very high in the household water of some of the distribution systems during 2011 and 2012 which exceeded the SANS 241 (2011) standard of ≤1000 CFU/ml. A large number of pigmented (yellow, orange, pink) and non-pigmented (white) colonies were isolated on R2A agar. This can be an indication of some failure in treatment processes. Other microbiological parameters that were tested such as faceal streptococci, Clostridia, Pseudomonas aeruginosa and fungi did not indicate any danger, but there were high levels of total anaerobic bacteria in the raw water during 2011 and 2012. A high level of anaerobic bacteria was detected in the household water of Hartswater during July 2011. Clostridia were also present in the household water of some of the distribution systems during 2011 and 2012. Sequencing results of the mdh, lacZ and uidA genes indicated that one of the isolates was identified as Enterobacter cloacae and the other isolates were E. coli. Four of the isolates were identified as Escherichia coli O104:H4. This is a pathogenic strain and raised concern. The physicochemical parameters that were measured complied with the SANS 241 (2011) standards during 2011 and 2012, but some of the parameters increased gradually from 2011 to 2012. Statistical analysis indicated that physico-chemical parameters had an influence on microbiological parameters and that deteriorating raw water may have an impact on drinking water quality. Another concern currently is that there is no SANS 241 (2011) for faecal streptococci, Clostridia, Pseudomonas aeruginosa, fungi and anaerobic bacteria. These are all opportunistic pathogenic bacteria and consuming water with high levels of these bacteria may cause health problems. This study indicated good progress in the treatment processes of the distribution systems over the two years. This may be due to the feedback given to Vaalharts Water during this study regarding the water quality of the residential areas. The physico-chemical and microbiological results of the present study indicated possible biofilm formation in the distribution systems. This may have impacts on the drinking water quality of the distribution systems. It was also evident that deteriorating raw water sources may have an impact on drinking water production. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.

Water quality in the Vaalharts region in the Northern Cape Province, South Africa, decreased over the past few years and there was a need for the microbiological and physico-chemical assessment. This problem was identified through discussions with Vaalharts Water (Vaalharts Water User Association) in 2010 when the issue of the impact of deteriorating water quality on drinking water production was raised. It was thus important to investigate concerns of the water users association pertaining to water quality issues. The aim of this study was to assess the physico-chemical and microbiological quality of household water in the Vaalharts irrigation scheme. The main residential areas were Hartswater, Pampierstad, Jan Kempdorp and Warrenton. Faecal coliforms were detected in the raw water of all the drinking water distribution systems during 2011 and 2012. No faecal coliforms were detected in the household water during 2011. This was a very positive result, because not only did the household water comply with the SANS 241 (2011) standard (0 CFU/100ml), but the purification processes were successful by removing all the E. coli’s from the raw water. However, during March 2012 faecal coliforms were detected in the household water of Jan Kempdorp (191CFU/100ml). This could be due to point pollution and possible breakage of faecal coliforms in the distribution system. Low amounts of total coliforms were detected in the raw water of some of the drinking water distribution systems. This could be due to high amounts of other colonies (pink and purple) growing on the m-Endo agar which suppress the growth of the metallic green sheen (total coliform) colonies. The total coliform numbers complied with the SANS 241 (2011) standard of ≤10 CFU/100ml at most of the distribution systems, except for Hartswater during July 2011 (14CFU/100ml) and Warrenton during March 2012 (256 CFU/100ml). Heterotrophic plate count bacteria were very high in the household water of some of the distribution systems during 2011 and 2012 which exceeded the SANS 241 (2011) standard of ≤1000 CFU/ml. A large number of pigmented (yellow, orange, pink) and non-pigmented (white) colonies were isolated on R2A agar. This can be an indication of some failure in treatment processes. Other microbiological parameters that were tested such as faceal streptococci, Clostridia, Pseudomonas aeruginosa and fungi did not indicate any danger, but there were high levels of total anaerobic bacteria in the raw water during 2011 and 2012. A high level of anaerobic bacteria was detected in the household water of Hartswater during July 2011. Clostridia were also present in the household water of some of the distribution systems during 2011 and 2012. Sequencing results of the mdh, lacZ and uidA genes indicated that one of the isolates was identified as Enterobacter cloacae and the other isolates were E. coli. Four of the isolates were identified as Escherichia coli O104:H4. This is a pathogenic strain and raised concern. The physicochemical parameters that were measured complied with the SANS 241 (2011) standards during 2011 and 2012, but some of the parameters increased gradually from 2011 to 2012. Statistical analysis indicated that physico-chemical parameters had an influence on microbiological parameters and that deteriorating raw water may have an impact on drinking water quality. Another concern currently is that there is no SANS 241 (2011) for faecal streptococci, Clostridia, Pseudomonas aeruginosa, fungi and anaerobic bacteria. These are all opportunistic pathogenic bacteria and consuming water with high levels of these bacteria may cause health problems. This study indicated good progress in the treatment processes of the distribution systems over the two years. This may be due to the feedback given to Vaalharts Water during this study regarding the water quality of the residential areas. The physico-chemical and microbiological results of the present study indicated possible biofilm formation in the distribution systems. This may have impacts on the drinking water quality of the distribution systems. It was also evident that deteriorating raw water sources may have an impact on drinking water production. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2013.

Made available in DSpace on 2015-04-17T14:49:45Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2168276 bytes, checksum: 5dbc05dbbef9f8d6f7a4c240e8bc725c (MD5) Previous issue date: 2010-11-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The marine shrimp Litopenaeus vannamei is a worldwide cultivated species, which is responsible for almost all the production of marine aquaculture in Brazil. Besides having a high nutritional value, it is also appreciated by consumers and there is the possibility of elaborating value-added products. The aim of this study is to evaluate the quality of the marine shrimp Litopenaeus vannamei in its lyophilizated form, using samples without pre-cooking and pre-cooked ones, and adding to them the tri and polyphospates and EDTA adictives. Experiences were made in order to determin the most adequate form of the shrimps rehydration and the physico-chemical analysis gathering centesimal composition, water activity, colour, water retention capacity, cholesterol level precision, fatty acids, aminoacids, vitamins, minerals, besides the caloric value, microbiological analysis and sensorial analysis. Lyophilization is a drying process in which the water passes from the solid to the vapor state, without going through the liquid state, leading to a decrease of the water activity and the food can be kept in room temperature. In this study, the rehydration was achieved in 2.5 minutes. The results showed that the Lyophilization process did not cause significant differences for water activity, pH and gain of weight in the rehydration. There has been a significantly different number for CRA in the TPF 5%-PC-L (99.99%). Lipids, proteins and ashes presented numbers with significant difference.The pré-cooked shrimps showed greater intensity of colour (62,05 to 71,06 for the angle a* and 19,22 to 32,59 for the angle b*). Phosphorus and Calcium presented figures between 189,06 and 301, 22 mg/100g. Cholesterol varied from 70,06 to 78,44 mg/100g. Fatty Acids with larger incidence were the mono and poliinsaturated. The aminoacids showed significant oscilations. The result of the sensorial analysis showed that the marine shrimp Litopenaeus vannamei lyophilizated is a product with a added value of great acceptation according to the consumers test. / O camarão marinho Litpenaeus vannamei é uma espécie cultivada em todo mundo, sendo responsável por quase toda produção da aquicultura marinha do Brasil. Além de ser um alimento de alto valor nutricional é bastante apreciado pelos consumidores podem ser elaborados produtos com valor agregado. Nesse contexto, de forma a avaliar a qualidade do camarão marinho, Litopenaeus vannamei, foram elaborados produtos sob a forma liofilizada utilizando-se amostras sem pre cozimento e pre cozidas, adicionadas dos aditivos tripolifosfato de sódio e EDTA. Foram realizados ensaios para a determinar a forma mais adequada da reidratação dos camarões e as análises físico-químicas envolvendo composição centesimal, atividade de água, cor, capacidade de retenção de água, determinação do teor de colesterol, ácidos graxos, aminoácidos, vitaminas, minerais, além do valor calórico, análises microbiológicas e analise sensorial. A liofilização, é um processo de secagem onde a água passa do estado sólido para o de vapor, sem passar pelo estado líquido, ocasionando uma redução da atividade de água e o alimento pode ser conservado em temperatura ambiente. No presente estudo a reidratação foi obtida em 2,5 minutos. Os resultados mostraram que o processo de liofilização não causou diferenças significativas para atividade de água, pH e ganho de peso na reidratação. Houve um valor significativamente diferente para CRA no TPF 5%-PC-L (99.99%). Lipídios, proteínas e cinzas apresentaram valores com diferença significativa. Os camarões pré cozidos apresentaram maior intensidade de cor (62,05 a 71,06 para o ângulo a* e 19,22 a 32,59 para o ângulo b*). Fósforo e Cálcio apresentaram valores entre 189,06 a 301, 22 mg/100g. Colesterol variou de 70,06 a 78,44 mg/100g. Os ácidos graxos com maior incidência foram os mono e poliinsaturados. Os aminoácidos apresentaram variações significativas. O resultado da análise sensorial mostrou que o camarão marinho Litopenaeus vannamei é um produto com valor agregado de grande aceitação pelo teste dos consumidores.