Aviation biofuel is technically viable and nearing the commercial stage. In the last 5 years aviation biofuel has moved from relative obscurity to become fully certified for commercial use in up to 50% blends with standard jet fuel. There have since been 15 successful commercial flight tests using aviation biofuels including Lufthansa s six month trial operating on a passenger revenue generating route in 2011. Airlines and biofuel companies such as British Airways and Solena are furthermore beginning to form partnerships to finance specialised aviation biofuel production facilities. However, aviation biofuels have yet to become widely commercialised. In fact, there are a series of issues preventing the emergence, development and uptake of aviation biofuels. The main issues are perceived as high costs of manufacture, limited availability of feedstocks, controversy surrounding the effect on food prices and the emissions output from land use change. Furthermore, there is a significant lack of academic peer reviewed literature which investigates these issues or offers solutions to support the development of the technology. This thesis aims to investigate the factors that affect the emergence, development and uptake of aviation biofuels by drawing upon in-depth stakeholder interviews and survey data. Strategic niche management (SNM) theory is used and extended to analyse the contemporary issues and develop recommendations to support the continued emergence, development and uptake of aviation biofuels. It is concluded that the emergence, development and uptake is being driven mainly by rising jet fuel prices, growing concern regarding aviation emissions legislation and fuel (in)security. Airlines, biofuel producers and specialised supply chain companies are driving emergence, development and uptake due to commercial opportunities. Despite these drivers, the emergence, development and uptake is being constrained by a combination of ineffective policy provision, high costs of production, limited feedstocks and uncertainty surrounding sustainability. Ineffective and unsuitable policy is exacerbating the issues of high production costs, limited feedstocks and sustainability. In particular, competition between aviation and road biofuels is limiting aviation biofuel expansion. Recommendations are to develop nurtured niche markets for aviation biofuels using principles from SNM. Within these markets, aviation biofuels are afforded commercial viability in order to learn about supply chain development, longer term infrastructural requirements and technological development. Information should be shared between the niche markets in order to maximise learning by doing and speed up efficiency gains. Once niche markets are established, the incentives and protection should be gradually reduced to allow a competitive aviation biofuel industry to develop.

Ferric ABC Transporters. Pathogenic bacteria have evolved specialised iron acquisition systems that allow them to effectively colonise a host. One of these systems is the ferric binding protein (Fbp) complex that is a member of the ATP-Binding Cassette (ABC) superfamily of small molecule transporters. The Fbp complex is made up of three-components (FbpABC) that transports ferric iron from the periplasm to the cytoplasm of many Gram negative bacteria. FbpA binds iron in the periplasm and transports it to the FbpB transporter complex that permeates the cytoplasmic membrane. Here the iron is actively transported by FbpB through the membrane that is powered by ATP hydrolysis catalysed by FbpC, the cytoplasmic ATPase. Burkholderia cenocepacia is an opportunist pathogen that colonises the lungs of cystic fibrosis patients and is particularly resistant to antibiotic treatment. In this study the iron uptake system of B. cenocepacia strain J2315 is investigated. A putative FbpA from B. cenocepacia J2315 was expressed in the periplasm of Escherichia coli cells and the recombinant FbpA B. cenocepacia protein purified. The structural and electrochemical properties of native FbpA B. cenocepacia were investigated using UV Visible spectroscopy, spectro-electrochemistry, mass spectrometry and crystallographic techniques. It appears that FbpA B. cenocepacia is a novel member of the FbpA superfamily that selectively utilises citrate as an exogenous anion in ferric iron co-ordination. This is the first instance that a recombinant ferric binding protein has been documented as preferentially utilising citrate in this manner. The putative ATPase from B. cenocepacia (FbpC B. cenocepacia) was also expressed in E. coli but it was found to be insoluble. A number of expression systems were tested but none were found to be successful in generating sufficient quantities of FbpC B. cenocepacia for structural studies. Human β-defensin 2. Despite daily contact with a range of microorganisms, mammals do not regularly succumb to pathogenic invasion. One reason is the presence of an important defence mechanism uses a reservoir of antimicrobial peptides (AMPs) that are expressed in eukaryotes as a means of innate immunity. The AMP superfamily is composed of over 900 members, displays broad structural and sequence diversity and is active against a wide range of bacteria, fungi and viruses. β-defensins are small (3-5 kDa), cationic peptides that display antimicrobial activity against a range of microbes and have also been shown to act as chemo-attractants (chemokines) within the adaptive immune system. In this study we obtained milligram amounts of pure human β-defensin 2 (HBD2) for functional studies by the development of a method for the rapid expression and purification of the recombinant peptide. A clone encoding a thioredoxin-HBD2 fusion protein was designed for the expression of soluble peptide in E. coli cells that was purified by simple affinity chromatography. The HBD2 peptide was cleaved from the fusion by an efficient protease step and further purified to yield pure HBD2. This recombinant HBD2 defensin was shown to be active against a Mycobacterium tuberculosis mutant strain.

A peptide nucleic acid (PNA) encoded 1296 member peptide library was synthesised and incubated with a variety of cell types. Library members entering cells were extracted, hybridised onto DNA microarrays and the peptide identity was determined via deconvolution. Global consensus analysis highlighted the tetrapepide, Glu-Llp- Glu-Glu (Llp is 6-hexamine-N-aminoacetic acid), a surprise in view of the basic residues typically observed in cell penetrating peptides. When evaluated, Glu-Llp- Glu-Glu revealed cellular uptake comparable to a known basic peptide (tetraLlp). In depth delineation via clustering analysis allowed assessment of differential cellular uptake, with the identified peptides showing clear cellular specificity. This was verified by peptide synthesis and cellular uptake analysis by flow-cytometry, and in all cases an endocytic uptake mechanism was confirmed. This approach establishes a strategy for the identification of short peptides as tools for selective delivery into specific cell types. The incubation of a 10,000 member PNA-encoded peptide library with D54 and HEK293T transfected with CCR6 cells followed by microarray analysis allowed detailed information on the interaction between peptide-ligands and cell surface receptors to be extracted. This allowed the identification of new ligands for integrins and G-protein coupled receptors and offers a novel approach to ligand discovery allowing the comparative analysis of different cell types for the identification of differences in surface-receptor ligands and/or receptor expression between various cell types. In addition, this work included the development of a novel method for the indirect amplification of a PNA library by amplification of a complementary DNA library hybridised to the PNA. The generation of 10,000 defined pieces of DNA would have a myriad of applications, not least in the area of defined or directed sequencing and synthetic biology, but also in applications associated with encoding and tagging. By this approach DNA microarrays were used to allow the linear amplification of immobilised DNA sequences on an array followed by PCR amplification. Arrays of increasing sophistication (1; 10; 3875; 10,000 defined oligonucleotides) were used to validate the process, with sequences verified by selective hybridisation to a complementary DNA microarray with DNA sequencing demonstrating error rates of ca ≈ 0.2%. This technique offers an economical and efficient way of producing hundreds to thousands of specific DNA primers, while the DNA-arrays can be used as “factories” allowing specific DNA oligonucleotide pools to be generated with or without masking. This study also demonstrated a significant variance observed between the sequence frequencies found via Solexa sequencing compared to microarray analysis.

Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2006. / High potassium content in grape juice and wine are associated with low quality red wine in warm wine producing countries. In an attempt to reduce the potassium content of juice, must and wine, a field experiment was laid out on the farms Meerlus and Kersfontein in the Paardeberg area near Wellington in 1998 on granite derived soils to investigate the effect of canopy management and fertiliser applications on berry K accumulation and wine quality. Four fertiliser applications, three canopy treatments and a MgSO4 foliar spray were studied. The three fertiliser treatments being: none (control), CaSO4, Ca(OH)2, and MgSO4 applications. The canopy treatments were: thin to two shoots per bearer, tip, vertical shoot positioning (VSP) and the removal of yellow leaves and lateral shoots (canopy 1), thin to three shoots per bearer, top after véraison and VSP (canopy 2) and VSP with top after véraison (canopy 3/control). Magnesium sulfate sprays were applied at véraison for two seasons (1999/00 and 2000/01). Seasonal effects produced the most significant differences in this experiment. Canopy treatments did not affect juice K concentration at harvest. Canopy 1 and 2 produced significantly lower wine pH values at Kersfontein. Fertiliser treatments had no effect on juice K concentration nor did it affect wine quality. Magnesium sulphate foliar sprays did not affect juice K concentration at harvest but significantly lowered juice and wine pH, improved wine colour density and total phenolic content. It appears for this experiment that soil K content before véraison, shoot growth at and after véraison and water stress after véraison were the main factors determining juice K concentration at harvest.

No description available.

The Human Immunodeficiency Virus and Acquired Immune Deficiency Syndrome (HIV/AIDS) continues to have enormous implications on the health, economic and psychosocial well-being of individuals, family structures, and communities. Sub-Saharan Africa is the region most affected by the HIV/AIDS. The purpose of this study is to investigate the social and cognitive factors associated with HIV test uptake in the general population of Kenya. Data from the 2009/2010 Kenya Demographic Health Survey were utilized. Univariate, bivariate and multivariate analyses were conducted using STATA/SE software. Results showed that there were statistically significant differences between men and women in previous HIV testing status and HIV test uptake. Over 90% of participants reported knowing a place to seek testing. The mean HIV related knowledge was higher in men than women (x =0.1; 95% CI 0.04-0.16) than women (x = 0.04; 95% CI [0.01- 0.1]). Differences were found in expressed HIV stigmatizing attitudes, with women reporting more stigmatizing attitudes than men. For example 9.9% of women compared to 4.7% of men reported very high HIV stigmatizing attitudes. Weighted multinomial regression analyses were conducted with individuals who had not been previously tested and unwilling to be tested utilized as the reference group. Among the factors found to be significantly associated with HIV uptake include: HIV related knowledge- higher levels of HIV related knowledge were associated with increased HIV test uptake for men and women, HIV related stigma- lower levels of HIV related stigma were significantly associated with HIV test uptake for women but not men, acceptance to teach condoms to children and knowledge of someone infected with HIV/AIDS was positively associated with HIV test uptake, gender- compared to men, women were significantly less likely to agree to be take the HIV/AIDS test if not previously tested (OR 0.79; 95% CI [0.64, 0.97]) but significantly more likely to accept the HIV/AIDS test when offered (OR 1.341; 95% CI [1.02, 1.76]). Other significant associations included: Age, education attainment, sex of head of household, and wanting to keep a family member's tuberculosis infection a secret.

No description available.

No description available.

Diagnosis of diabetes mellitus, presence of hyperglycemia, and/or insulin resistance confer cardiovascular risk, particularly for diastolic dysfunction. Diabetes is associated with elevated myocardial norepinephrine (NE) content, enhanced sympathetic nervous system (SNS) activity, altered resting heart rate, and depressed heart rate variability. Positron emission tomography (PET) using the NE analogue [11C]meta-hydroxyephedrine ([11C]HED) provides an index of myocardial sympathetic neuronal integrity at the NE reuptake transporter (NET). The hypothesis of this project is that (i) hyperglycemia imparts heightened sympathetic tone and NE release, leading to abnormal sympathetic neuronal function in the hearts of diabetic rats, and (ii) these abnormalities may be reversed or prevented by treatments to normalize glycemia. Sprague Dawley rats were rendered insulin resistant by high fat feeding and diabetic by a single dose of streptozotocin (STZ). Diabetic rats were treated for 8 weeks with insulin, metformin or rosiglitazone, starting from either 1 week (prevention) or 8 weeks (reversal) after STZ administration. Sympathetic neuronal integrity was evaluated longitudinally by [11C]HED PET. Echocardiography measures of systolic and diastolic function were completed at serial timepoints. Plasma NE levels were evaluated serially and expression of NET and β-adrenoceptors were tested at the terminal endpoints. Diabetic rats exhibited a 52-57% reduction of [11C]HED standardized uptake value (SUV) at 8 weeks after STZ, with a parallel 2.5-fold elevation of plasma NE and a 17-20% reduction in cardiac NET expression. These findings were confirmed by ex vivo biodistribution studies. Transmitral pulse wave Doppler echocardiography established an extension of mitral valve deceleration time and elevated early to atrial velocity ratio, suggesting diastolic dysfunction. Subsequent treatment with insulin but not metformin restored glycemia, reduced plasma NE by 50%, normalized NET expression, and recovered [11C]HED SUV towards non-diabetic age-matched control. Diastolic dysfunction in these rats persisted. By contrast, early treatment with insulin, metformin, or rosiglitazone delayed the progression of diastolic dysfunction, but had no effect on elevated NE and reduced [11C]HED SUV in diabetic rats, potentially owing to a latent decrease in blood glucose. In conclusion, diabetes is associated with heightened circulating and tissue NE levels which can be effectively reversed by lowering glycemia with insulin. Noninvasive interrogation of sympathetic neuronal integrity using [11C]HED PET may have added value in the stratification of cardiovascular risk among diabetic patients and in determining the myocardial effects of glycemic therapy.

The purpose of this study was to assess the changes in maximal oxygen consumption and cardiorespiratory responses to maximal treadmill exercise of men, who engaged in intense physical training for more than 35-years. Thirteen men were first studied in 1969 and were re-examined in 1992 as a 25-year follow-up. The men were divided into two groups, group 1 (G1) and group 2 (G2). G1 (current age = 54.6 years) consisted of seven men who were Division I cross country runners in the late 1960's, and G2 (current age = 67.5 years) were highly active at the initial testing and were 14 years older than the men of G1 at all test dates. A maximal exercise test revealed a significant decrease in absolute and realtiveVO2ma, over the 35-years for both G1 and G2. G2 experienced a significant decline in VO2max when expressed in relative and absolute terms after the age of 56.5 years which occurred after the 25-year test. Maximal heat rate decreased over the 35-year period for both G1 (187.7 to 165.8 bpm) and G2 (181 to 164.7bpm), however only GI revealed a trend between the 25-and 35-year tests. O2pulse significantly decreased from the initial testing to the 35-year period in G2 (23.1 to 19.5 ml/beat). Body composition changes were evident with aging in that both GI and G2 had a significant increase in percent body fat over the 35-years however, only Gl had a significant increase in body weight at both the 25-and 35-year follow-up.These data suggest that aging and a reduced training regimen may have a significant effect upon VO2m and cardiorespiratory and body composition measures. It appears that after the age of 56 years, a greater reduction in VO2max occurs, which is accompanied by greater changes in stroke volume. Although the aerobic capacity of these men declined over the 35-year period, the values obtained by all men far exceeded the values reported for sedentary and less active men in other studies. Therefore, as previously reported, aging is associated with a reduction in aerobic capacity, however continued endurance training can reduce the rate at which aerobic capacity declines. / Fisher Institute for Wellness and Gerontology