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Photophysical studies of Zinc phthalocyanine-silica nanoparticles conjugates
No full textThis thesis reports on the synthesis and characterization of both symmetrical and asymmetrical Zinc phthalocyanine complexes. The complexes contained groups such as carboxylic, amino and alkyne for covalent grafting to the surface of silica nanoparticles. The use of symmetrical and asymmetrical complexes was geared towards comparing the non-specific binding of the symmetrical complexes to the specific binding observed in the asymmetrical complexes. The complexes were also doped within the silica matrix and compared to the surface grafted conjugates. The complexes and the conjugates were well characterized with a variety of techniques.
The fluorescence lifetimes of the phthalocyanine complexes containing either terminal carboxylic groups or an alkyne group showed a mono-exponential decay while the amino containing phthalocyanine complexes gave a bi-exponential decay. A similar trend was observed for their respective conjugates.
Some of the conjugates of the asymmetrical complexes showed a decrease in fluorescence lifetimes and a corresponding decrease in fluorescence quantum yields. The fluorescence quantum yields for all the symmetrical complexes studied showed either an improvement or retained the luminescence of the grafted phthalocyanine complex. Most of the conjugates showed a faster intersystem crossing time in comparison to the complexes alone. The grafted or doped conjugates containing symmetrical phthalocyanine complexes with carboxyl groups showed improvements both in fluorescence and triplet quantum yields. All the conjugates except two showed an increase in triplet lifetimes when compared to their respective phthalocyanine complexes.
Optical nonlinearities of nine of the phthalocyanine complexes were studied and all the complexes showed characteristic reverse saturable absorption behavior. Complex 10 showed the most promising optical limiting behavior. The aggregation and dissolution studies of the conjugates were also carried out in a simulated biological medium and the silicon level detected was noticed to have increased with incubation time
The cognitive rehabilitation of a sample of children living with HIV : a specific focus on the cognitive rehabilitation of sustained attention
No full textPharmacological interventions to treat Human Immunodeficiency Virus (HIV) with
antiretrovirals (ARVs), have dramatically improved the survival rates of HIV positive
children maturing into adulthood. However, HIV-associated neurocognitive decline still
persists in the era of ARVs. Within the framework of brain plasticity, a number of researchers
have begun to assess the feasibility of cognitive rehabilitation therapy as a complement to
ARVs to reverse neurocognitive decline as a result of HIV (e.g., Becker et al., 2012). Only
one study has been conducted in South Africa, by Zondo & Mulder (2014), assessing the
efficacy of cognitive rehabilitation in a paediatric sample. The current research builds on the
above mentioned study by implementing an experimental approach to examine the effect of
cognitive rehabilitation in a sample of both HIV positive and HIV negative children. Five
HIV positive and six HIV negative children were assigned to either an experimental or
control group. The experimental group underwent two months of cognitive rehabilitation
therapy remediating sustained attention, whereas the control group took part in placebo
activities. Sustained attention measures were taken before and after the intervention training
sessions, using a sustained attention subtest from the Test of Everyday Attention for Children
(TEA-CH). A Mann Whitney U Test revealed that the experimental group (Mdn=38.50) did
not differ significantly from the control group (Mdn = 37.00) after the cognitive rehabilitation
intervention, U=12.00, z= -.55, p= .66, r= -.17. But a Wilcoxon Signed Rank Test found that
there was a significant improvement from pretest scores (Mdn=31.00) to posttest scores
(Mdn=38.00) following the rehabilitation for HIV positive participants in the sample,
T=15.00, z = -2.02, p= .04, r= -.90. This raises the possibility that cognitive rehabilitation
could be used as a low cost intervention in underdeveloped context
The effect of GH family affiliations of mannanolytic enzymes on their synergistic associations during the hydrolysis of mannan-containing substrates
No full textMetallophthalocyanine-gold nanoparticle conjugates for photodynamic antimicrobial chemotherapy
No full textThis thesis presents the synthesis of neutral and cationic metallophthalocyanines and their gold nanoparticles conjugates. The spectroscopic characterization of these compounds is presented herein. The studies presented in this work shows that the conjugation of gold nanoparticles influenced both photophysical and photochemical properties.
Gold nanoparticles were found to enhance the singlet oxygen quantum yield while lowering the fluorescence quantum yields. This work also looks at the effect of anisotropic gold nanoparticles such as nanorods and bipyramids on the photophysical behaviour of the metallophthalocyanines. The effect of the size of the gold nanorods was investigated herein. The results show that photophysical and photochemical properties can be influenced by both size and shape of the nanoparticles. Physical characterization about the loading of nanoparticles was also looked into. Parameters such as the surface area, the number of surface atoms, the number of atoms as well as the number of nanoparticles loaded on the surface of the phthalocyanines were studied. The self-assembled monolayers formed by phthalocyanines on gold surfaces were studied using the X-ray photoelectron spectroscopy (XPS).
The gold nanoparticles synthesized herein include both organic and water soluble, different capping agents (citrate, tetraammonium bromide (TAOBr) and cetrimethylammonium bromide (CTAB). The concentration of the gold nanoparticles was measured on the inductively coupled plasma (ICP) and their size and shape were obtained from the transmission electron microscopy (TEM) images.
A cationic aluminium phthalocyanine and its conjugates were used for photoinactivation of bacteria and fungi. The results show significant reduction and higher activity in the presence of gold nanoparticles, especially nanorods.
A small chapter in this work presents an attempted work on the binding of metallothionein protein with protophorphyrin (IX). The pH and concentration dependent binding studies were investigate
Financial Accounting III:FAC30P1/FAV30Z1/ FAC30B1FAC30Q1
No full textExamination on Financial Accounting III: FAC30P1/ FAC30Z1/ FAC30B1/FAC30Q
Management Accounting III : MAC3011
No full textExamination on Management Accounting : MAC3011, June 201
Organisational Management III
No full textExamination on Organisational Management III, ORM3011, June 201
Public Procurement & Logistics II : PLM21B1
No full textExamination on Public Procurement & Logistics II : PLM21B1, June 201
Sexual socialisation in Life Orientation manuals versus popular music: Responsibilisation versus pleasure, tension and complexity
No full textThis paper compares two forms of sexual socialisation to which learners are exposed:the sexuality education components of the Life Orientation (LO) manuals and the lyrical content and videos of popular songs. We performed a textual analysis of the sexual subject positions made available in, first, the LO manuals used in Grade 10 classes and, second, the two songs voted most popular by the Grade 10 learners of two diverse schools in the Eastern Cape. Of interest in this paper is whether and how these two forms of sexual socialisation – one representing state-sanctioned
sexual socialisation and the other learners’ chosen cultural expression that represents informal sexual socialisation – dovetail or diverge. Against a backdrop of heterosexuality and an assumption of the ‘adolescent-in-transition’ discourse, the main sexual subject positions featured in the LO manuals are the responsible sexual subject and the sexual victim. A number of sexualised subject positions are portrayed in the songs, with these subject positions depicting sex as a site of pleasure, tension and complexity. Although these two modes of sexual socialisation use different genres of communication, we argue that learners’ choice of songs that depict fluid sexual subject positions can help to inform LO sexuality education in ways that takes learners’ preferred cultural expression seriously and that moves away from the imperative of responsibilisation
Post-treatment technologies for integrated algal pond systems
No full textIntegrated Algae Pond Systems (IAPS) are a derivation of the Oswald designed Algal Integrated Wastewater Pond Systems (AIWPS®) and combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. IAPS technology was introduced to South Africa in 1996 and a pilot plant designed and commissioned at the Belmont Valley WWTW in Grahamstown. The system has been in continual use since implementation and affords a secondarily treated water for reclamation according to its design specifications which most closely resemble those of the AIWPS® Advanced Secondary Process developed by Oswald. As a consequence, and as might be expected, while the technology performed well and delivered a final effluent superior to most pond systems deployed in South Africa it was unable to meet The Department of Water Affairs General Standard for nutrient removal and effluent discharge. The work described in this thesis involved the design, construction, and evaluation of several tertiary treatment units (TTU') for incorporation into the IAPS process design. Included were; Maturation Ponds (MP), Slow Sand Filter (SSF) and Rock Filters (RF). Three MP's were constructed in series with a 12 day retention time and operated in parallel with a two-layered SSF and a three-stage RF. Water quality of the effluent emerging from each of these TTU's was monitored over a 10 month period. Significant decreases in the chemical oxygen demand (COD), ammonium-N, phosphate-P, nitrate-N, faecal coliforms (FC) and total coliforms (TC) were achieved by these TTU's. On average, throughout the testing period, water quality was within the statutory limit for discharge to a water course that is not a listed water course, with the exception of the total suspended solids (TSS). The RF was determined as the most suitable TTU for commercial use due to production of a better quality water, smaller footprint, lower construction costs and less maintenance required. From the results of this investigation it is concluded that commercial deployment of IAPS for the treatment of municipal sewage requires the inclusion of a suitable TTU. Furthermore, and based on the findings presented, RF appears most appropriate to ensure that quality of the final effluent meets the standard for discharge