List of Titles

Nanoconjugates of CdTe@ ZnS quantum dots with cobalt tetraamino-phthalocyanine

- Adegoke, Oluwasesan, Antunes, Edith M, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Antunes, Edith M , Nyokong, Tebello
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/242049 , vital:50996 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.02.010"
Description: The covalent linking of thiol-capped CdTe@ZnS QDs with cobalt tetraamino-phthalocyanine (CoTAPc) has been successfully carried out. Several techniques such as time-resolved fluorescence measurements, thermal gravimetric analysis,transmissionelectronmicroscopy andspectrophotometric techniques were employed to characterize the nanoconjugates. Covalent binding of the QDs with CoTAPc resulted in the fluorescence quenching of the former. In the presence of varying concentrations of superoxide anion (O2 •−), the fluorescence of the QDs in the conjugate was gradually enhanced and the detection limits obtained were 2.1 and 2.4 nM for the smaller and larger QDs, respectively. Based on the excellent selectivity displayed by the nanoconjugates towards O2 •− over other biologically active species, a potential nanosensor was developed.
Full Text:

Nanostructured β-cyclodextrin-hyperbranched polyethyleneimine (β-CD-HPEI) embedded in polysulfone membrane for the removal of humic acid from water

- Malinga, S P, Arotiba, O A, Mapolie, S F, Diallo, M S, Mamba, Bhekie B, Krause, Rui W M

Authors: Malinga, S P , Arotiba, O A , Mapolie, S F , Diallo, M S , Mamba, Bhekie B , Krause, Rui W M
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/125119 , vital:35732 , https://doi.org/10.1080/01496395.2013.809108
Description: The synthesis of a new β-cyclodextrin-hyperbranched polyethyleneimine (β-CD-HPEI)/polysulfone (PSf) membranes via interfacial polymerization of trimesoyl chloride and β-CD-HPEI is described in this paper. The membranes were characterized by atomic force microscopy (AFM), high resolution scanning electron microscopy (HR-SEM) and contact-angle measurements. Water permeability and rejection data were obtained using a cross-flow filtration system at 0.69 MPa. The membranes were hydrophilic (25° to 63°), showed high humic acid rejection (>amp;80%), and maintained a constant flux throughout the filtration. The modified membranes were rougher than the pristine PSf membranes but they exhibited better antifouling properties due to the hydrophilic surface which acted as a barrier against humic acid deposition. The modification of PSf with β-CD-HPEI resulted in enhanced hydrophilicity and water permeability while still maintaining high humic acid rejection. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science & Technology to view the supplemental file.
Full Text:

Quick View

New ways of understanding: a governmentality analysis of basic education policy in post-apartheid South Africa

- Prinsloo, Estelle Helena

Authors: Prinsloo, Estelle Helena
Date: 2013
Subjects: South Africa -- Department of Basic Education , Basic education -- Government policy -- Research -- South Africa , Post-apartheid era -- Education -- South Africa , Educational change -- Research -- South Africa , South Africa -- Social conditions
Language: English
Type: text , Thesis , Masters , MA
Identifier: vital:2751 , http://hdl.handle.net/10962/d1001384
Description: Social problems that are identified by government policy are articulated in ways that confer the responsibility of their management onto the state. In this way, policy reform serves as a means to justify political rule, as the ‘answers’ to policy failures are located within the realm of state intervention. This role of policy is maintained by the traditional definition of policy as it enables policies to be presented as the outcome of ‘necessary’ actions taken by state institutions to better the wellbeing of citizens. Since 1994, mainstream research on basic education policy in South Africa has employed traditional understandings of policy and its function. In doing so, these inquiries have failed to question the very idea of policy itself. They have also neglected to identify the productive role played by policy in the practice of power. To illuminate the necessary limits of policy reform, an alternative approach to analyse basic education policy is necessary. This thesis premises policy as discourse and advances a governmentality analysis of basic education policy during the first fifteen years of democracy (1994-2009) in South Africa. By drawing on the work of Michel Foucault, the study argues that government – ‘those actions upon the actions of others’ – during this period in South Africa was informed by both a liberal and a neo-liberal mentality of rule. The tensions between these two rationalities contributed to the continuation of apartheid’s socio-economic inequalities in the postapartheid era; an outcome buttressed by the contradictory impulses within basic education policy. By considering policy as a productive translation of governmental reasoning, the boundaries of intervention for future policy reforms are highlighted. These show that the inequalities that were perpetuated during the first fifteen years of democracy justify policy responses similar to those responsible for their production
Full Text:

Quick View

Newspapers as ‘community members’: Editorial responses to the death of Eugene Terre'Blanche

- Smith, Jade, Adendorff, Ralph

Authors: Smith, Jade , Adendorff, Ralph
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/125320 , vital:35771 , https://doi.org/10.1080/10228195.2012.702778
Description: This article uses the appraisal system to expose covert meanings surrounding white supremacist Eugène Terre’Blanche’s murder in editorials from three South African newspapers: The Citizen, Sowetan and The Times. Following Martin and White’s (2005) framework, inscribed and evoked Attitudinal meanings are identified to prove an ‘us versus them’ perspective of Terre’Blanche’s death. Graduation and Engagement strategies supplement this, illustrating how meanings are modified or organized to align readers. The analysis reveals surface attempts to present a ‘balanced view’ of this racially-sensitive event; however, beneath this is clear blame allocation. Additionally, the covert evaluation is explained by Coffin and O’Halloran’s (2006) theory of ‘dog-whistling’, where only aligned readers can detect underlying meanings. This creates the imagined community – ‘us’ – of which the newspaper is seen as a trusted member. Print media, it could be inferred, is symbolic of other South African community members, who mask their evaluations with a politically correct façade.
Full Text:

Quick View

Nonlinear optical behavior of metal octaphenoxy phthalocyanines

- Sanusi, Sikiru O, Antunes, Edith M, Nyokong, Tebello

Authors: Sanusi, Sikiru O , Antunes, Edith M , Nyokong, Tebello
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/241717 , vital:50963 , xlink:href="https://doi.org/10.1142/S1088424613500715"
Description: In this work, we investigated the nonlinear optical absorption properties of chloroaluminum, chlorogallium, chloroindium, zinc and lead octaphenoxy phthalocyanines in a dimethyl sulphoxide solution using 5 ns pulses at 532 nm. Using the Z-scan technique, the nonlinear optical properties and the excited state absorption cross-sections were determined by fitting the Z-scan data. The k value was the highest for Pb derivative at 211, making it the best nonlinear optical material. In terms of hyperpolarizability, Pb derivative (containing a larger central metal) also gave the largest value followed by aluminum derivative (containing a small central metal). The distortion of the ring caused by the central metal is used to explain the hyperpolarizability values. Large nonlinear absorption coefficient values, βeff, in the range of 3.558–4.763 × 10-9 cm.W-1 and low saturation fluence values, Fsat between 21.5–38.5 mJ.cm-2, were obtained for these samples.
Full Text:

Quick View

Novel applications of Morita-Baylis-Hillman methodology in organic synthesis

- Mciteka, Lulama Patrick

Authors: Mciteka, Lulama Patrick
Date: 2013 , 2013-04-22
Subjects: Organic compounds -- Synthesis -- Research Asymmetric synthesis Asymmetry (Chemistry) Chemical reactions -- Research Camphor -- Research AZT (Drug) -- Research Chemical inhibitors -- Research Chemistry -- Methodology
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4439 , http://hdl.handle.net/10962/d1007598
Description: The overall approach in the present investigation has been to explore applications of the Morita-Baylis-Hillman (MBH) reaction in asymmetric synthesis and in the continuation of systems with medicinal potential. To this end, a series of varied camphor-derived acrylate esters was prepared to serve as chiral substrates in asymmetric Morita-Baylis- Hillman reactions. Reduction of N-substituted camphor-10-sulfonamides afforded the 3- exo-hydroxy derivatives as the major products. Acylation of the corresponding sodium alkoxides gave the desired 3-exo-acrylate esters, isolation of which was complicated by concomitant formation of hydrochlorinated and diastereomeric competition products. Bulky camphorsulfonamides containing alkyl, dialkyl, aromatic and adamantyl groups were selected as N-substituents with the view of achieving stereoselective outcome in subsequent MBH reactions. The synthesis of novel camphor-derived Morita-Baylis-Hillman adducts using various pyridine-carboxaldehydes proceeded with exceptionally high yields with diastereoselectivities ranging from 7-33 % d.e. Both 1D and 2D NMR and HRMS techniques were employed to confirm the structures and an extensive study of the electropositive fragmentation patterns of a number of camphor-derived chiral acrylate esters was conducted. Attention has also been given to the application of MBH methodology in the construction of heterocyclic ‘cinnamate-like’ AZT conjugates which were designed to serve as dualaction HIV-1 integrase-reverse transcriptase (IN-RT) inhibitors. A number of pyridine carboxaldehyde-derived MBH adducts were synthesized using methyl, ethyl and t-butyl acrylates in the presence of 3-hydroxyquinuclidine (3-HQ) as catalyst. The yields for these reactions were excellent. The resulting MBH adducts were acetylated and subjected to aza-Michael addition using propargylamine. The resulting alkylamino compounds were then used in ‘Click reactions’ to form the targeted AZT-conjugates in moderate to excellent yield. In silico docking of computer modelled AZT-conjugates into the HIV-1 integrase and reverse transcriptase enzyme-active sites and potential hydrogen-bonding interaction with active-site amino acid residues were identified. The electrospray MS fragmentations of the AZT and the novel AZT-conjugates were also investigated and common fragmentation pathways were identified.
Full Text:

Quick View

Numerical relativity on cosmological past null cones

- Van der Walt, Petrus Johannes

Authors: Van der Walt, Petrus Johannes
Date: 2013
Subjects: Cosmology Numerical calculations General relativity (Physics) -- Mathematics Einstein field equations Gravity Gravitational waves Horizon
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:5396 , http://hdl.handle.net/10962/d1002959
Description: The observational approach to cosmology is the endeavour to reconstruct the geometry of the Universe using only data that is theoretically verifiable within the causal boundaries of a cosmological observer. Using this approach, it was shown in [36] that given ideal cosmological observations, the only essential assumption necessary to determine the geometry of the Universe is a theory of gravity. Assuming General Relativity, the full set of Einstein field equations (EFEs) can be used to reconstruct the geometry of the Universe using direct observations on the past null cone (PNC) as initial conditions. Observationally and theoretically this is a very ambitious task and therefore, current developments have been restricted to spherically symmetric dust models while only relaxing the usual assumption of homogeneity in the radial direction. These restricted models are important for the development of theoretical foundations and also useful as verification models since they avoid the circularity of verifying what has already been assumed. The work presented in this thesis is the development of such a model where numerical relativity (NR) is used to simulate the observable universe. Similar to the work of Ellis and co-workers [36], a reference frame based on the PNC is used. The reference frame used here, however, is based on that of the characteristic formalism of NR, which has developed for calculating the propagation of gravitational waves. This provides a formalism that is well established in NR, making the use of existing algorithms possible. The Bondi-Sachs coordinates of the characteristic formalism is, however, not suitable for calculations beyond the observer apparent horizon (AH) since the diameter distance used as a radial coordinate becomes multi-valued when the cosmological PNC reconverges in the history of a universe, smaller in the past. With this taken into consideration, the Bondi-Sachs characteristic formalism is implemented for cosmology and the problem approaching the AH is investigated. Further developments address the limitations approaching the AH by introducing a metric based on the Bondi-Sachs metric where the radial coordinate is replaced with an affine parameter. The model is derived with a cosmological constant Λ incorporated into the EFEs where Λ is taken as a parameter of the theory of gravity rather than as a matter source term. Similar to the conventional characteristic formalism, this model consists of a system of differential equations for numerically evolving the EFEs as a characteristic initial value problem (CIVP). A numerical code implemented for the method has been found to be second order convergent. This code enables simulations of different models given identical data on the initial null cone and provides a method to investigate their physical consistency within the causally connected region of our current PNC. These developments closely follow existing 3D schemes developed for gravitational wave simulations, which should make it natural to extend the affine CIVP beyond spherical symmetric simulations. The developments presented in this thesis is an extended version of two papers published earlier.
Full Text:

Quick View

Nutrient-mediated effects on Cornops aquaticum Brüner (Orthoptera: Acrididae), a potential biological control agent of water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae)

- Bownes, Angela, Hill, Martin P, Byrne, Marcus J

Authors: Bownes, Angela , Hill, Martin P , Byrne, Marcus J
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/406131 , vital:70241 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.07.023"
Description: Environmental nutrient availability can drive and modify both plant responses to herbivory by phytophagous insects and insect feeding patterns which, in insect-weed systems, may ultimately determine whether biological control succeeds or fails. The impacts of insect biological control agents on the invasive aquatic weed, water hyacinth (Eichhornia crassipes) vary with nutrient levels in the environment. It was therefore considered important to evaluate nutrient-specific responses of E. crassipes to a grasshopper herbivore, Cornops aquaticum, prior to its release in South Africa. Both plant productivity and the response of E. crassipes to herbivory by C. aquaticum were nutrient dependent. Increases in plant biomass and leaf and ramet production were correlated with increases in nutrients in the water and plant biomass accumulation was reduced by herbivory at all three nutrient levels tested (high = 67%; medium = 100%; low = 400%). C. aquaticum nymphs fed E. crassipes leaves with the lowest nitrogen levels produced the highest biomass of frass during their development, indicating compensatory consumption. The results suggest that environmental nutrient availability will influence efficacy of C. aquaticum. They also provide further evidence that E. crassipes problems are exacerbated by an over-abundance of nutrients in aquatic environments, and that biological control would be a highly effective management tool if aquatic systems in South Africa were less polluted. Additionally, the results also show how an understanding of the fundamental responses of E. crassipes and its insect biocontrol agents to their environment can assist in determining specific management strategies or interventions according to prevailing site-specific conditions.
Full Text:

Quick View

Obituary: John Mayne English 1922-2013

- Lewis, Colin A

Authors: Lewis, Colin A
Date: 2013
Language: English
Type: Article , text
Identifier: vital:6162 , http://hdl.handle.net/10962/d1004782
Description: In 1962 John moved south to Johannesburg, but that bustling city held few attractions for him and he moved further south, to the cathedral city of Grahamstown. Grahamstown, with its nineteenth century Gothic cathedral, elegant Georgian buildings, and distinctive grandeur of Rhodes University, St Andrew's College and other buildings designed by Herbert Baker and his colleagues, suited John. He particularly enjoyed the academic, social, artistic and dramatic life of the community, where many older members of society were distinguished old-Africa hands. John thoroughly enjoyed Grahamstown where, in the partnership of Hoskins and English, he made his mark in the restoration and extension of many significant buildings. His addition to the Anglican chapel at Hog's Back is a masterpiece, as is his incorporation of the old fayade into the rebuilding and extension of the Magistrates' Court.
Full Text:

Quick View

Observables in a lattice Universe : the cosmological fitting problem

- Bruneton, J-P, Larena, Julien

Authors: Bruneton, J-P , Larena, Julien
Date: 2013
Language: English
Type: Article
Identifier: vital:6790 , http://hdl.handle.net/10962/d1006943
Description: We explore observables in a lattice Universe described by a recently found solution to Einstein field equations. This solution models a regular lattice of evenly distributed objects of equal masses. This inhomogeneous solution is perturbative, and, up to second order in a small parameter, it expands at a rate exactly equal to the one expected in a dust dominated Friedmann-Lema^itre-Robertson-Walker (FLRW) model with the equivalent, smoothed, energy density. Therefore, the kinematics of both cosmologies are identical up to the order of perturbation studied. Looking at the behaviour of the redshift and angular distance, we find a condition on the compactness of the objects at the centre of each cell under which corrections to the FLRW observables remain small, i.e. of order of a few percents at most. Nevertheless, we show that, if this condition is violated, i.e. if the objects are too compact, our perturbative scheme breaks down as far as the calculations of observables are concerned, even though the kinematics of the lattice remains identical to its FLRW counter-part (at the perturbative order considered). This may be an indication of an actual fitting problem, i.e. a situation in which the FLRW model obtained from lightcone observables does not correspond to the FLRW model obtained by smoothing the spatial distribution of matter. Fully non-perturbative treatments of the observables will be necessary to answer that question.
Full Text:

Quick View

On the implementation effectiveness and efficiency of ecological interventions in operational contexts : the case of Working for Water

- McConnachie, Matthew Morgan

Authors: McConnachie, Matthew Morgan
Date: 2013
Subjects: Working for Water Programme Alien plants -- South Africa -- Eastern Cape Alien plants -- Control -- South Africa -- Eastern Cape Alien plants -- Control -- Cost effectiveness -- South Africa -- Eastern Cape Conservation of natural resources -- South Africa -- Eastern Cape Acacia mearnsii -- South Africa -- Eastern Cape Poverty -- South Africa -- Eastern Cape Revegetation -- South Africa -- Eastern Cape Restoration ecology -- South Africa -- Eastern Cape Environmental degradation -- South Africa -- Eastern Cape
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4729 , http://hdl.handle.net/10962/d1001956
Description: There is little understanding of the implementation efficiency and effectiveness of restoring plant invaded landscapes within operational contexts. South Africa's Working for Water (WfW) programme is arguably the most ambitious alien plant control programme in the world, yet little is known about its cost-effectiveness and the challenges it faces in linking poverty and environmental objectives. My first aim was to assess the cost-effectiveness of invasive plant removal, and the factors that underpin its effectiveness over large spatial and temporal scales. The second aim was to compare the accuracy of evidence-based findings with managers' experience-based beliefs, and to assess whether managers are willing to change their beliefs after being exposed to it. The third aim was to assess the costs and benefits of removal versus removal followed by active native re-vegetation. My final aim is to assess the challenges and lessons learnt by managers linking ecological restoration with poverty alleviation objectives, specifically within the public works model. My study area was focused primarily on two WfW river catchment projects in the western region of the Eastern Cape province. I adopted an interdisciplinary approach drawing from a range of methods such as observational studies, statistical modelling and interviews with managers. The key findings were that control efforts in the two catchment projects are largely inadequate owing to many sites being re-invaded and not enough resources being allocated to the catchments. It would take between 54 and 695 years to clear the respective catchments. In terms of cost-effectiveness, my results exceeded previous estimates by 1.5 to 8.6 times for each catchment project. After being exposed to the evidence-based findings, the managers did not change their beliefs when it came to forecasting the future effectiveness. I found that active native re-vegetation after removal of invasive plants is very costly and that priority should be given to understanding the effectiveness of the removal treatments on native species recovery. The managers cited significant challenges in effectively and efficiently meeting the programmes dual objectives. Based on a broader review of the public works literature I recommend WfW re-examine the type of public works they currently use.
Full Text:

Quick View

Open debate: ephemeral democracies: interrogating commonality in South Africa

- Makhubu, Nomusa

Authors: Makhubu, Nomusa
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/147626 , vital:38655 , https://0-doi.org.wam.seals.ac.za/10.1080/09528822.2013.796200
Description: South Africa's Post-Apartheid era is characterized by the rhetoric of ‘unity in diversity’. However, numerous artist-led public interventions disclose alienating socio-economic conditions. Neoliberal reforms in the context of prevailing structural designs of Apartheid in South Africa weaken the democratization process, making it figurative rather than tangible and participatory. There is a pervasive perception that centres of power within the arts in South Africa are located in institutions of white proprietorship. As a result, young artists create independent establishments where they can have some control over cultural production and dissemination. This article debates the different strategies that are used by young practising artists to confront contemporary challenges in Post-Apartheid South Africa. One of these strategies promotes integration and deracialization through persistent engagement with predominantly white institutions in order to generate a sense of common purpose while the other opts for the power of provocative racialized but marginalized cultural movements.
Full Text:

Quick View

Optical limiting analysis of phthalocyanines in polymer thin films

- Britton, Jonathan, Litwinski, Christian, Antunes, Edith M, Durmus, Mahmut, Chaukea, Vongani, Nyokong, Tebello

Authors: Britton, Jonathan , Litwinski, Christian , Antunes, Edith M , Durmus, Mahmut , Chaukea, Vongani , Nyokong, Tebello
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/232488 , vital:49996 , xlink:href="https://doi.org/10.1080/10601325.2013.736269"
Description: This paper reports on the effect of embedding twelve phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films on their optical limiting abilities. This paper also examines the effect of forming a covalent link between zinc tetraamino phthalocyanine (10) and poly (methyl acrylic acid) (PMAA), and Zn (11) or OHAl (12) octacarboxy phthalocyanines with polyethylenimine (PEI). The average film thickness (for phthalocyanines mixed or linked to polymers) of each Pc/Polymer films on glass was 95 μm. The hyperpolarizability of the twelve phthalocyanines was found to be in the range of 10−26 to 10−24 esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution, which ranged from 10−30 to 10−26 esu.L. Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation.
Full Text:

Quick View

Oral literature in Africa

- Kaschula, Russell H

Authors: Kaschula, Russell H
Date: 2013
Subjects: Folk literature -- Study and teaching -- Africa , Oral tradition -- Africa , Folklore and education -- Africa , Books -- Africa -- Reviews
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/59355 , vital:27563 , https://doi.org/10.1080/13696815.2012.756804
Description: I have in my possession a first edition, hard copy of Ruth Finnegan’s quintessential work, Oral Literature in Africa. It has a yellow cover, preserved by a plastic sheathe, it is a little frayed around the edges and has that old, musty library smell about it. I love and treasure this book. It is dedicated by Professor Finnegan ‘[t]o all my teachers’. Professor Finnegan is indeed one of my teachers. I properly met Ruth Finnegan at the second International Society for Oral Literature (ISOLA) conference in 1998, which I hosted at the University of Cape Town. She gave a keynote address which included reference to her seminal work and the future of oral literary studies. She has continually influenced our work as researchers following in her footsteps: Isidore Okpewho, Harold Scheub, Abiola Irele, Graham Furniss, Elizabeth Gunner, Karin Barber, Isobel Hofmeyr, John Foley, Olayibi Yai, Edgard Sienaert, Brian Street, Noverino Canonici, Mark Turin, Daniela Merolla, Jan Jansen, Jeff Opland, and many others; some younger, some older, some living, some departed, scholars influenced by this great and humble intellectual and her body of work.
Full Text:

Quick View

Overcrowding of false codling moth, Thaumatotibia leucotreta (Meyrick) leads to the isolation of five new Cryptophlebia leucotreta granulovirus (CrleGV-SA) isolates

- Opoku-Debrah, John K, Hill, Martin P, Knox, Caroline, Moore, Sean D

Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline , Moore, Sean D
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/419360 , vital:71637 , xlink:href="https://doi.org/10.1016/j.jip.2012.12.008"
Description: False codling moth, Thaumatotibia leucotreta (Meyrick) is a serious pest of economic importance to the South African fruit industry. As part of sustainable efforts to control this pest, biological control options that involve the application of baculovirus-based biopesticides such as Cryptogran and Cryptex (both formulated with a South African isolate of Cryptophlebia leucotreta granulovirus, CrleGV-SA) are popularly used by farmers. In order to safeguard the integrity of these biopesticides as well as protect against any future development of resistance in the host, we conducted a study to bioprospect for additional CrleGV isolates as alternatives to existing ones. Using overcrowding as an induction method for latent infection, we recovered five new CrleGV isolates (CrleGV-SA Ado, CrleGV-SA Mbl, CrleGV-SA Cit, CrleGV-SA MixC and CrleGV-SA Nels). Single restriction endonuclease (REN) analysis of viral genomic DNA extracted from purified occlusion bodies showed that isolates differed in their DNA profiles. Partial sequencing of granulin and egt genes from the different isolates and multiple alignments of nucleotide sequences revealed the presence of single nucleotide polymorphisms (SNPs), some of which resulted in amino acid substitutions in the protein sequence. Based on these findings as well as comparisons with other documented CrleGV isolates, we propose two phylogenetic groups for CrleGV-SA isolates recovered in this study.
Full Text:

Quick View

Oxovanadium (IV)-containing poly (styrene-co-4′-ethenyl-2-hydroxyphenylimidazole) electrospun nanofibers for the catalytic oxidation of thioanisole

- Walmsley, Ryan S, Litwinski, Christian, Antunes, Edith M, Hlangothi, Percy, Hosten, Eric, McCleland, Cedric, Nyokong, Tebello, Torto, Nelson, Tshentu, Zenixole R

Authors: Walmsley, Ryan S , Litwinski, Christian , Antunes, Edith M , Hlangothi, Percy , Hosten, Eric , McCleland, Cedric , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/241665 , vital:50959 , xlink:href="https://doi.org/10.1016/j.molcata.2013.07.018"
Description: The catalytic fibers have been fabricated by the electrospinning of a copolymer of styrene and 2-(2′-hydroxy-4′-ethenylphenyl)imidazole {p(ST-co-VPIM)} followed by a reaction with a methanolic vanadyl solution to afford the oxovanadium(IV)-containing poly(styrene-co-4′-ethenyl-2-hydroxyphenylimidazole) fibers {p(ST-co-VPIM)-VO fibers}. The relationship between polymer concentration and fiber diameter was investigated, and at high concentration (20 wt%) the fibers were quite large (average diameter of 3.8 μm) but as the concentration was reduced fibers of much lower diameter were produced (0.6 μm using 8 wt%). The BET surface area for p(ST-co-VPIM) fibers (0.6 μm diameter) was 47.9 m2 g−1 and functionalization of p(ST-co-VPIM) with vanadyl resulted in an increase in surface area to 60.7 m2 g−1 for p(ST-co-VPIM)-VO. The presence of vanadyl was confirmed by XPS and EPR. The EPR spectral analyses depicted complex speciation of vanadium within these polymer supports. These catalytic fibers were applied under batch and continuous flow conditions for the catalytic oxidation of thioanisole using hydrogen peroxide. The continuous flow method gave excellent and constant conversion throughout the 10 h period studied. The leaching of vanadium from the fiber support was 4% over the 10 h period indicating a significant stability of the material.
Full Text:

Showing items 321 - 340 of 588