The importance of long-term post-release studies in classical biological control: Insect–plant monitoring and public awareness of water hyacinth management (Pontederia crassipes) in Dique Los Sauces, Argentina
- Faltlhauser, Ana C, Jiménez, Nadia L, Righetti, Tomas, Visintin, Andrés M, Torrens, Javier, Salinas, Nicolás A, Mc Kay, Fernando, Hill, Martin P, Cordo, Hugo A, Sosa, Alejandro J
- Authors: Faltlhauser, Ana C , Jiménez, Nadia L , Righetti, Tomas , Visintin, Andrés M , Torrens, Javier , Salinas, Nicolás A , Mc Kay, Fernando , Hill, Martin P , Cordo, Hugo A , Sosa, Alejandro J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424828 , vital:72187 , xlink:href="https://doi.org/10.1111/eea.13355"
- Description: Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post-release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north-eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long-term post-release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle-aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post-release evaluations including outreach campaigns to make a sustainable successful management programme.
- Full Text:
- Date Issued: 2023
- Authors: Faltlhauser, Ana C , Jiménez, Nadia L , Righetti, Tomas , Visintin, Andrés M , Torrens, Javier , Salinas, Nicolás A , Mc Kay, Fernando , Hill, Martin P , Cordo, Hugo A , Sosa, Alejandro J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424828 , vital:72187 , xlink:href="https://doi.org/10.1111/eea.13355"
- Description: Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post-release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north-eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long-term post-release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle-aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post-release evaluations including outreach campaigns to make a sustainable successful management programme.
- Full Text:
- Date Issued: 2023
Shifting contexts: contemporary South African art in changing times
- Authors: Ntombela, N
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146200 , vital:38504 , ISBN 9781869143398 , https://books.google.co.za/books?id=xZlAjySD5-cCandq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsdq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsl=ensa=Xved=0ahUKEwjJ3oOGgcDpAhVuURUIHQyoAnIQ6AEIJzAA
- Description: Book abstract. The pernicious combination of tribe and tradition continues to tether modern South Africans to ideas about the region's remote past as primitive, timeless, and unchanging. Any hunger for knowledge or understanding of the past before European colonialism remains to a significant degree unsated in the face of a narrowly prescribed archive and repugnant, but insidiously resilient, stereotypes. These volumes track how the domain of the tribal and traditional came to be sharply distinguished from modernity, how it was denied a changing history and an archive, and was endowed instead with a timeless culture. They also offer strategies for engaging with the materials differently-from the interventions effected in contemporary artworks to the inserting of nameless, timeless objects of material culture into histories of individualized and politicized experience. The two volume set make this archive of material culture visible as an archival resource. They also seek to spring the identity trap, releasing the material from pre-assigned identity positions as tribal into settings that enable them to be used as resources for thinking critically about identity.
- Full Text:
- Date Issued: 2019
- Authors: Ntombela, N
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146200 , vital:38504 , ISBN 9781869143398 , https://books.google.co.za/books?id=xZlAjySD5-cCandq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsdq=Tribing+and+Untribing+the+Archive:+Identity+and+the+Material+Record+in+Southern+KwaZulu-Natal+in+the+Late+Independent+and+Colonial+Periodsl=ensa=Xved=0ahUKEwjJ3oOGgcDpAhVuURUIHQyoAnIQ6AEIJzAA
- Description: Book abstract. The pernicious combination of tribe and tradition continues to tether modern South Africans to ideas about the region's remote past as primitive, timeless, and unchanging. Any hunger for knowledge or understanding of the past before European colonialism remains to a significant degree unsated in the face of a narrowly prescribed archive and repugnant, but insidiously resilient, stereotypes. These volumes track how the domain of the tribal and traditional came to be sharply distinguished from modernity, how it was denied a changing history and an archive, and was endowed instead with a timeless culture. They also offer strategies for engaging with the materials differently-from the interventions effected in contemporary artworks to the inserting of nameless, timeless objects of material culture into histories of individualized and politicized experience. The two volume set make this archive of material culture visible as an archival resource. They also seek to spring the identity trap, releasing the material from pre-assigned identity positions as tribal into settings that enable them to be used as resources for thinking critically about identity.
- Full Text:
- Date Issued: 2019
Colonised minds?: post-development theory and the desirability of development in Africa
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
- Date Issued: 2017
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
- Date Issued: 2017
Counting on demographic equity to transform institutional cultures at historically white South African universities?:
- Booi, Masixole, Vincent, Louise, Liccardo, Sabrina
- Authors: Booi, Masixole , Vincent, Louise , Liccardo, Sabrina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141946 , vital:38018 , DOI: 10.1080/07294360.2017.1289155
- Description: The post-apartheid higher education transformation project is faced with the challenge of recruiting and retaining black academics and other senior staff. But when we shift the focus from participation rates to equality–inequality within historically white universities (HWUs), then the discourse changes from demographic equity and redress to institutional culture and diversity. HWUs invoke the need to maintain their position as leading higher education institutions globally, and notions of ‘quality’ and ‘excellence’ have emerged as discursive practices, which serve to perpetuate exclusion. The question then arises as to which forms of capital comprise the Gold Standard at HWUs? Several South African universities have responded to the challenge of recruiting and retaining black academics by initiating programmes for the ‘accelerated development’ of these candidates.
- Full Text:
- Date Issued: 2017
- Authors: Booi, Masixole , Vincent, Louise , Liccardo, Sabrina
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141946 , vital:38018 , DOI: 10.1080/07294360.2017.1289155
- Description: The post-apartheid higher education transformation project is faced with the challenge of recruiting and retaining black academics and other senior staff. But when we shift the focus from participation rates to equality–inequality within historically white universities (HWUs), then the discourse changes from demographic equity and redress to institutional culture and diversity. HWUs invoke the need to maintain their position as leading higher education institutions globally, and notions of ‘quality’ and ‘excellence’ have emerged as discursive practices, which serve to perpetuate exclusion. The question then arises as to which forms of capital comprise the Gold Standard at HWUs? Several South African universities have responded to the challenge of recruiting and retaining black academics by initiating programmes for the ‘accelerated development’ of these candidates.
- Full Text:
- Date Issued: 2017
Decoupled reciprocal subsidies of biomass and fatty acids in fluxes of invertebrates between a temperate river and the adjacent land:
- Moyo, Sydney, Chari, Lenin D, Villet, Martin H, Richoux, Nicole B
- Authors: Moyo, Sydney , Chari, Lenin D , Villet, Martin H , Richoux, Nicole B
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140843 , vital:37923 , DOI: 10.1007/s00027-017-0529-0
- Description: Streams and riparian areas are tightly coupled through reciprocal trophic subsidies, and there is evidence that these subsidies affect consumers in connected ecosystems. Most studies of subsidies consider only their quantity and not their quality. We determined the bidirectional exchange of organisms between the Kowie River and its riparian zone in South Africa using floating pyramidal traps (to measure insect emergence) and pan traps (to capture infalling invertebrates).
- Full Text:
- Date Issued: 2017
- Authors: Moyo, Sydney , Chari, Lenin D , Villet, Martin H , Richoux, Nicole B
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140843 , vital:37923 , DOI: 10.1007/s00027-017-0529-0
- Description: Streams and riparian areas are tightly coupled through reciprocal trophic subsidies, and there is evidence that these subsidies affect consumers in connected ecosystems. Most studies of subsidies consider only their quantity and not their quality. We determined the bidirectional exchange of organisms between the Kowie River and its riparian zone in South Africa using floating pyramidal traps (to measure insect emergence) and pan traps (to capture infalling invertebrates).
- Full Text:
- Date Issued: 2017
Forensic entomotoxicology revisited: towards professional standardisation of study designs
- da Silva, Erica I T, Wilhelmi, Brendan S, Villet, Martin H
- Authors: da Silva, Erica I T , Wilhelmi, Brendan S , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140819 , vital:37921 , DOI: 10.1007/s00414-017-1603-9
- Description: Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology.
- Full Text:
- Date Issued: 2017
- Authors: da Silva, Erica I T , Wilhelmi, Brendan S , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140819 , vital:37921 , DOI: 10.1007/s00414-017-1603-9
- Description: Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology.
- Full Text:
- Date Issued: 2017
MD-TASK: a software suite for analyzing molecular dynamics trajectories
- Brown, David K, Penkler, David L, Amamuddy, Olivier S, Ross, Caroline J, Atilgan, Ali R, Atilgan, Canan, Tastan Bishop, Özlem
- Authors: Brown, David K , Penkler, David L , Amamuddy, Olivier S , Ross, Caroline J , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125138 , vital:35735 , https://doi.10.1093/bioinformatics/btx349
- Description: Molecular dynamics (MD) determines the physical motions of atoms of a biological macromolecule in a cell-like environment and is an important method in structural bioinformatics. Traditionally, measurements such as root mean square deviation, root mean square fluctuation, radius of gyration, and various energy measures have been used to analyze MD simulations. Here, we present MD-TASK, a novel software suite that employs graph theory techniques, perturbation response scanning, and dynamic cross-correlation to provide unique ways for analyzing MD trajectories.
- Full Text:
- Date Issued: 2017
- Authors: Brown, David K , Penkler, David L , Amamuddy, Olivier S , Ross, Caroline J , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125138 , vital:35735 , https://doi.10.1093/bioinformatics/btx349
- Description: Molecular dynamics (MD) determines the physical motions of atoms of a biological macromolecule in a cell-like environment and is an important method in structural bioinformatics. Traditionally, measurements such as root mean square deviation, root mean square fluctuation, radius of gyration, and various energy measures have been used to analyze MD simulations. Here, we present MD-TASK, a novel software suite that employs graph theory techniques, perturbation response scanning, and dynamic cross-correlation to provide unique ways for analyzing MD trajectories.
- Full Text:
- Date Issued: 2017
Pessimistic assessment of white shark population status in South Africa: comment on Andreotti et al.(2016)
- Irion, Dylan T, Noble, Leslie R, Kock, Alison A, Gennari, Enrico, Dicken, Matthew L, Hewitt, Adrian M, Towner, Alison V, Booth, Anthony J, Smale, Malcolm J, Cliff, Geremy
- Authors: Irion, Dylan T , Noble, Leslie R , Kock, Alison A , Gennari, Enrico , Dicken, Matthew L , Hewitt, Adrian M , Towner, Alison V , Booth, Anthony J , Smale, Malcolm J , Cliff, Geremy
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:35799 , https://doi.10.3354/meps12283
- Description: Andreotti et al. (2016; Mar Ecol Prog Ser 552:241−253) estimate an abundance (N) of 438 white sharks Carcharodon carcharias and a contemporary effective population size (CNe) of 333 individuals along the South African coast. N was estimated by using a mark-recapture analysis of photographic identification records from a single aggregation site (Gansbaai). CNe was calculated based on the levels of pairwise linkage disequilibrium of genetic material collected from 4 aggregation sites across approximately 965 km of South African coastline. However, due to the complex stock structure of white sharks and the model assumptions made by Andreotti et al. (2016), the conclusions drawn cannot be supported by their methods and data.
- Full Text:
- Date Issued: 2017
- Authors: Irion, Dylan T , Noble, Leslie R , Kock, Alison A , Gennari, Enrico , Dicken, Matthew L , Hewitt, Adrian M , Towner, Alison V , Booth, Anthony J , Smale, Malcolm J , Cliff, Geremy
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:35799 , https://doi.10.3354/meps12283
- Description: Andreotti et al. (2016; Mar Ecol Prog Ser 552:241−253) estimate an abundance (N) of 438 white sharks Carcharodon carcharias and a contemporary effective population size (CNe) of 333 individuals along the South African coast. N was estimated by using a mark-recapture analysis of photographic identification records from a single aggregation site (Gansbaai). CNe was calculated based on the levels of pairwise linkage disequilibrium of genetic material collected from 4 aggregation sites across approximately 965 km of South African coastline. However, due to the complex stock structure of white sharks and the model assumptions made by Andreotti et al. (2016), the conclusions drawn cannot be supported by their methods and data.
- Full Text:
- Date Issued: 2017
Rhodes University Graduation Ceremony 2017
- Authors: Rhodes University
- Date: 2017
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/58067 , vital:27061
- Description: 2017 Graduation Ceremony, Umsitho Wothweso-Zidanga, Gradeplegtigheid [at] 1820 Settlers National Monument, Thursday, 20 April until Saturday, 22 April 2017.
- Full Text:
- Date Issued: 2017
- Authors: Rhodes University
- Date: 2017
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/58067 , vital:27061
- Description: 2017 Graduation Ceremony, Umsitho Wothweso-Zidanga, Gradeplegtigheid [at] 1820 Settlers National Monument, Thursday, 20 April until Saturday, 22 April 2017.
- Full Text:
- Date Issued: 2017
Synthesis, characterisation and evaluation of benzoxaborole-based hybrids as antiplasmodial agents
- Authors: Gumbo, Maureen
- Date: 2017
- Subjects: Malaria Chemotherapy , Antimalarials , Boron compounds , Drug resistance , Plasmodium falciparum , Drug development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59193 , vital:27456
- Description: Malaria is a mosquito-borne disease, which continues to pose a threat to the entire humanity. About 40% of the world population is estimated to be at risk of infections by malaria. Despite efforts undertaken by scientific community, government entities and international organizations, malaria is still rampant. The major problem is drug resistance, where the Plasmodium spp have over the past decades developed drug resistance against available drugs. In order to counter this problem, novel antimalarial drugs that are efficacious and with novel mode of action are of great necessity. Benzoxaborole derivatives have been shown to exhibit promising antimalarial activity against Plasmodium falciparum strains. Previous studies reported on the compounds such as 6-(2- (alkoxycarbonyl)pyrazinyl-5-oxy)-1,3-dihydro-1-hydroxy-2,1-benzoxaboroles, which showed good antimalarial activity against both W7 and 3D7 strains without significant toxicity. On the other hand, chloroquine (CQ) and cinnamic acids have a wide variety of biological activity including antimalarial activity. Herein, a hybridisation strategy was employed to synthesise new CQ-benzoxaborole and cinnamoyl-benzoxaborole hybrids. CQ-Benzoxaborole 2.12a-c and cinnamoylbenzoxaborole 2.11a-g hydrid molecules were synthesised in low to good yields. Their structural identities were confirmed using conventional spectroscopic techniques (1H and 13C NMR, and mass spectrometry). CQ-benzoxaborole compounds, however, showed instability, and only 2.12b was used for in vitro biological assay and showed activity comparable to CQ. Furthermore, in vitro biological assay revealed that compounds 2.11a-g poorly inhibited the growth of P. falciparum parasites. Interestingly, these compounds, however, exhibited satisfactory activity against Trypanosoma brucei with IC50 = 0.052 μM for compound 2.11g. The cell cytotoxicity assay of all final compounds confirmed that all CQ-benzoxaborole 2.12b and cinnamoyl-benzoxaborole 2.11a-g hybrids were non-toxic against HeLa cell lines. However, efforts to further expand the structure-activity relationship (SAR) of CQbenzoxaborole by increasing the length of the linker with one extra carbon (Scheme 2.10) were not possible as an important precursor 6-formylbenzoxaborole 2.29 could not be synthesized in sufficient yields. , Thesis (MSc) -- Faculty of Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017
- Authors: Gumbo, Maureen
- Date: 2017
- Subjects: Malaria Chemotherapy , Antimalarials , Boron compounds , Drug resistance , Plasmodium falciparum , Drug development
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/59193 , vital:27456
- Description: Malaria is a mosquito-borne disease, which continues to pose a threat to the entire humanity. About 40% of the world population is estimated to be at risk of infections by malaria. Despite efforts undertaken by scientific community, government entities and international organizations, malaria is still rampant. The major problem is drug resistance, where the Plasmodium spp have over the past decades developed drug resistance against available drugs. In order to counter this problem, novel antimalarial drugs that are efficacious and with novel mode of action are of great necessity. Benzoxaborole derivatives have been shown to exhibit promising antimalarial activity against Plasmodium falciparum strains. Previous studies reported on the compounds such as 6-(2- (alkoxycarbonyl)pyrazinyl-5-oxy)-1,3-dihydro-1-hydroxy-2,1-benzoxaboroles, which showed good antimalarial activity against both W7 and 3D7 strains without significant toxicity. On the other hand, chloroquine (CQ) and cinnamic acids have a wide variety of biological activity including antimalarial activity. Herein, a hybridisation strategy was employed to synthesise new CQ-benzoxaborole and cinnamoyl-benzoxaborole hybrids. CQ-Benzoxaborole 2.12a-c and cinnamoylbenzoxaborole 2.11a-g hydrid molecules were synthesised in low to good yields. Their structural identities were confirmed using conventional spectroscopic techniques (1H and 13C NMR, and mass spectrometry). CQ-benzoxaborole compounds, however, showed instability, and only 2.12b was used for in vitro biological assay and showed activity comparable to CQ. Furthermore, in vitro biological assay revealed that compounds 2.11a-g poorly inhibited the growth of P. falciparum parasites. Interestingly, these compounds, however, exhibited satisfactory activity against Trypanosoma brucei with IC50 = 0.052 μM for compound 2.11g. The cell cytotoxicity assay of all final compounds confirmed that all CQ-benzoxaborole 2.12b and cinnamoyl-benzoxaborole 2.11a-g hybrids were non-toxic against HeLa cell lines. However, efforts to further expand the structure-activity relationship (SAR) of CQbenzoxaborole by increasing the length of the linker with one extra carbon (Scheme 2.10) were not possible as an important precursor 6-formylbenzoxaborole 2.29 could not be synthesized in sufficient yields. , Thesis (MSc) -- Faculty of Faculty of Science, Chemistry, 2017
- Full Text:
- Date Issued: 2017
A chiral hemiporphyrazine derivative
- Wu, Yanping, Gai, Lizhi, Xiao, Xuqiong, Lu, Hua, Li, Zhifang, Mack, John, Harris, Jessica, Nyokong, Tebello, Shen, Zhen
- Authors: Wu, Yanping , Gai, Lizhi , Xiao, Xuqiong , Lu, Hua , Li, Zhifang , Mack, John , Harris, Jessica , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240404 , vital:50831 , xlink:href="https://doi.org/10.1002/asia.201600754"
- Description: The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
- Full Text:
- Date Issued: 2016
- Authors: Wu, Yanping , Gai, Lizhi , Xiao, Xuqiong , Lu, Hua , Li, Zhifang , Mack, John , Harris, Jessica , Nyokong, Tebello , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240404 , vital:50831 , xlink:href="https://doi.org/10.1002/asia.201600754"
- Description: The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1. An irreversible one-electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one-electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
- Full Text:
- Date Issued: 2016
A comparative physicochemical study of unsymmetrical indium phthalocyanines in the presence of magnetic nanoparticles or quantum dots
- Osifeko, Olawale L, Nyokong, Tebello
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188743 , vital:44781 , xlink:href="https://doi.org/10.1080/00958972.2016.1152628"
- Description: Asymmetric indium phthalocyanine (3, containing an NH2 group) was conjugated (via an amide bond) to magnetic nanoparticle (MNP) functionalized with carboxylic acid or glutathione-capped CdTe/ZnSe/ZnO quantum dots to form 3-MNPs or 3-QDs. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, XPS, elemental analysis, FTIR, NMR (1H, 13C, and cozy), electronic spectroscopy, as well as mass spectroscopy were employed to characterize 3 and its nanoconjugates. The phthalocyanine conjugated to quantum dot (3-QDs) possesses the lowest Фpd higher Ф∆ and ФT as well as longer triplet lifetimes compares to 3-MNPs and free phthalocyanine.
- Full Text:
- Date Issued: 2016
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188743 , vital:44781 , xlink:href="https://doi.org/10.1080/00958972.2016.1152628"
- Description: Asymmetric indium phthalocyanine (3, containing an NH2 group) was conjugated (via an amide bond) to magnetic nanoparticle (MNP) functionalized with carboxylic acid or glutathione-capped CdTe/ZnSe/ZnO quantum dots to form 3-MNPs or 3-QDs. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, XPS, elemental analysis, FTIR, NMR (1H, 13C, and cozy), electronic spectroscopy, as well as mass spectroscopy were employed to characterize 3 and its nanoconjugates. The phthalocyanine conjugated to quantum dot (3-QDs) possesses the lowest Фpd higher Ф∆ and ФT as well as longer triplet lifetimes compares to 3-MNPs and free phthalocyanine.
- Full Text:
- Date Issued: 2016
A Geopolitics of knowledge and the value of discomfort:
- Authors: Simbao, Ruth K
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146444 , vital:38526 , https://www.ru.ac.za/fineart/latestnews/alutacontinuadoingitfordaddytenyearson.html
- Description: In 2006, the short essay ‘Doing it for Daddy’ by visual artist Sharlene Khan caused controversy when it expressed the opinion that since 1994, ‘transformation’ in the visual arts field in South Africa seemed to have halted at the point of White women replacing White men in positions of power. It questioned this new position of dominance in institutions that remained colonially and racially untransformed. On the 16 and 17th of September 2016, the School of Fine Art at Rhodes University will host a one-day symposium ‘A luta Continua: Doing it for Daddy - Ten years on…’ which seeks to both commemorate that article and those who ‘speak up’, but also, fundamentally, to continue looking at the ways in which various social oppressions intersect in the fields of art history and visual arts in South Africa. Presenters include Khwezi Gule, Nontobeko Ntombela, Nomusa Makhubu, Same Mdluli, Fouad Asfour, Ruth Simbao, Sharlene Khan, students from Wits School of Arts and Rhodes Art History and Visual Culture, as well as a performance by visual artist Sikhumbuzo Makandula.
- Full Text:
- Date Issued: 2016
- Authors: Simbao, Ruth K
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146444 , vital:38526 , https://www.ru.ac.za/fineart/latestnews/alutacontinuadoingitfordaddytenyearson.html
- Description: In 2006, the short essay ‘Doing it for Daddy’ by visual artist Sharlene Khan caused controversy when it expressed the opinion that since 1994, ‘transformation’ in the visual arts field in South Africa seemed to have halted at the point of White women replacing White men in positions of power. It questioned this new position of dominance in institutions that remained colonially and racially untransformed. On the 16 and 17th of September 2016, the School of Fine Art at Rhodes University will host a one-day symposium ‘A luta Continua: Doing it for Daddy - Ten years on…’ which seeks to both commemorate that article and those who ‘speak up’, but also, fundamentally, to continue looking at the ways in which various social oppressions intersect in the fields of art history and visual arts in South Africa. Presenters include Khwezi Gule, Nontobeko Ntombela, Nomusa Makhubu, Same Mdluli, Fouad Asfour, Ruth Simbao, Sharlene Khan, students from Wits School of Arts and Rhodes Art History and Visual Culture, as well as a performance by visual artist Sikhumbuzo Makandula.
- Full Text:
- Date Issued: 2016
A River of Blood Flows: Lerato Shadi’s ‘Noka Ya Bokamoso’
- Authors: Makandula, Sikhumbuzo
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147258 , vital:38609 , https://artthrob.co.za/2016/07/13/a-river-of-blood-flows-lerato-shadis-noka-ya-bokamoso/
- Description: The title of Lerato Shadi’s show, ‘Noka Ya Bokamoso,’ which opened at National Arts Festival in Grahamstown, translates from Setswana to ‘a river of tomorrow.’ In the Albany gallery you encounter Shadi performing Mosako Wa Nako. She sits silently crocheting a ball of red wool into a scroll which unfurls with indecipherable writing. Shadi’s isolation from the rest of the artworks on the exhibition draws you closer, emphasising the rhythmic movement of her hands.
- Full Text:
- Date Issued: 2016
- Authors: Makandula, Sikhumbuzo
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147258 , vital:38609 , https://artthrob.co.za/2016/07/13/a-river-of-blood-flows-lerato-shadis-noka-ya-bokamoso/
- Description: The title of Lerato Shadi’s show, ‘Noka Ya Bokamoso,’ which opened at National Arts Festival in Grahamstown, translates from Setswana to ‘a river of tomorrow.’ In the Albany gallery you encounter Shadi performing Mosako Wa Nako. She sits silently crocheting a ball of red wool into a scroll which unfurls with indecipherable writing. Shadi’s isolation from the rest of the artworks on the exhibition draws you closer, emphasising the rhythmic movement of her hands.
- Full Text:
- Date Issued: 2016
Academic literacy and the decontextualised learner
- Boughey, Chrissie, McKenna, Sioux
- Authors: Boughey, Chrissie , McKenna, Sioux
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/64651 , vital:28585 , http://www.DOI:10.14426/cristal.v4i2.80
- Description: The literacy practices that are valued in the university emerge from specific disciplinary histories yet students are often expected to master these as if they were common sense and natural. This article argues that the autonomous model of literacy, which sees language use as the application of a set of neutral skills, continues to dominate in South African universities. This model denies the extent to which taking on disciplinary literacy practices can be difficult and have implications for identity. It also allows disciplinary norms to remain largely opaque and beyond critique. Furthermore, the autonomous model of literacy is often coupled with a discourse of the ‘decontextualised learner’ who is divorced from her social context, with higher education success seen to be resting largely upon attributes inherent in, or lacking from, the individual. Sadly, alternative critical social understandings have not been widely taken up despite their being well researched. Indeed, such understandings have often been misappropriated in ways that draw on critical social terminology to offer autonomous, decontextualised, remedial student interventions. We argue that these issues are implicated in students’ accusations that universities are alienating spaces.
- Full Text:
- Date Issued: 2016
- Authors: Boughey, Chrissie , McKenna, Sioux
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/64651 , vital:28585 , http://www.DOI:10.14426/cristal.v4i2.80
- Description: The literacy practices that are valued in the university emerge from specific disciplinary histories yet students are often expected to master these as if they were common sense and natural. This article argues that the autonomous model of literacy, which sees language use as the application of a set of neutral skills, continues to dominate in South African universities. This model denies the extent to which taking on disciplinary literacy practices can be difficult and have implications for identity. It also allows disciplinary norms to remain largely opaque and beyond critique. Furthermore, the autonomous model of literacy is often coupled with a discourse of the ‘decontextualised learner’ who is divorced from her social context, with higher education success seen to be resting largely upon attributes inherent in, or lacking from, the individual. Sadly, alternative critical social understandings have not been widely taken up despite their being well researched. Indeed, such understandings have often been misappropriated in ways that draw on critical social terminology to offer autonomous, decontextualised, remedial student interventions. We argue that these issues are implicated in students’ accusations that universities are alienating spaces.
- Full Text:
- Date Issued: 2016
Age and growth of Cape stumpnose Rhabdosargus holubi (Pisces: Sparidae) in the Eastern Cape, South Africa
- Farthing, Matthew William, James, Nicola Caroline, Potts, Warren M
- Authors: Farthing, Matthew William , James, Nicola Caroline , Potts, Warren M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/122891 , vital:35365 , https://doi.org/10.2989/1814232X.2016.1156577
- Description: Rhabdosargus holubi (Steindachner, 1881) is a small (maximum size = 450 mm total length; Heemstra and Heemstra 2004) sparid that is distributed along the south-east coast of Africa from St Helena Bay, South Africa, to Maputo, Mozambique (Götz and Cowley 2013). Spawning occurs in the nearshore marine environment primarily during winter, specifically May–August in KwaZulu-Natal (KZN) (Wallace 1975) and July–February in the South-Eastern Cape (Whitfield 1998). Individuals reach 50% sexual maturity at approximately 150 mm standard length (SL) in the Eastern Cape (Whitfield 1998). The early life stages are transported by the south-westward-flowing Agulhas Current, and recruit as post-flexion larvae and early juveniles into estuaries during late winter and early summer (Blaber 1974). The warm temperatures and high nutrient levels in estuaries favour fast growth (Blaber 1973a), and fish spend their first year of life in these environments, migrating back out to sea after reaching approximately 120 mm SL. Some individuals remain trapped in closed estuaries, where they may reach sizes greater than 200 mm SL (James et al. 2007a). Rhabdosargus holubi is the dominant estuarine-dependent marine teleost species recorded in permanently open and temporarily open/closed estuaries in the warm-temperate region, which spans the south, south-east and east coast of South Africa (Harrison 2005). The species is also an important component of the linefishery in many SouthAfrican estuaries (10–15.6% by number) (Pradervand and Baird 2002), particularly in Eastern Cape estuaries (Cowley et al. 2003). These figures underestimate the presence of R. holubi, as most individuals making use of estuaries are young, feeding predominately on filamentous macroalgae and diatom flora, and are generally too small to be caught with hook and line (De Wet and Marais 1990). James et al. (2007b) showed that R. holubi made up 34–92% of the annual seine-net catch in the East Kleinemonde Estuary. Rhabdosargus holubi is also important in the KZN shorebased linefishery, representing 4.6% of the total landed catch (Dunlop and Mann 2012).
- Full Text:
- Date Issued: 2016
- Authors: Farthing, Matthew William , James, Nicola Caroline , Potts, Warren M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/122891 , vital:35365 , https://doi.org/10.2989/1814232X.2016.1156577
- Description: Rhabdosargus holubi (Steindachner, 1881) is a small (maximum size = 450 mm total length; Heemstra and Heemstra 2004) sparid that is distributed along the south-east coast of Africa from St Helena Bay, South Africa, to Maputo, Mozambique (Götz and Cowley 2013). Spawning occurs in the nearshore marine environment primarily during winter, specifically May–August in KwaZulu-Natal (KZN) (Wallace 1975) and July–February in the South-Eastern Cape (Whitfield 1998). Individuals reach 50% sexual maturity at approximately 150 mm standard length (SL) in the Eastern Cape (Whitfield 1998). The early life stages are transported by the south-westward-flowing Agulhas Current, and recruit as post-flexion larvae and early juveniles into estuaries during late winter and early summer (Blaber 1974). The warm temperatures and high nutrient levels in estuaries favour fast growth (Blaber 1973a), and fish spend their first year of life in these environments, migrating back out to sea after reaching approximately 120 mm SL. Some individuals remain trapped in closed estuaries, where they may reach sizes greater than 200 mm SL (James et al. 2007a). Rhabdosargus holubi is the dominant estuarine-dependent marine teleost species recorded in permanently open and temporarily open/closed estuaries in the warm-temperate region, which spans the south, south-east and east coast of South Africa (Harrison 2005). The species is also an important component of the linefishery in many SouthAfrican estuaries (10–15.6% by number) (Pradervand and Baird 2002), particularly in Eastern Cape estuaries (Cowley et al. 2003). These figures underestimate the presence of R. holubi, as most individuals making use of estuaries are young, feeding predominately on filamentous macroalgae and diatom flora, and are generally too small to be caught with hook and line (De Wet and Marais 1990). James et al. (2007b) showed that R. holubi made up 34–92% of the annual seine-net catch in the East Kleinemonde Estuary. Rhabdosargus holubi is also important in the KZN shorebased linefishery, representing 4.6% of the total landed catch (Dunlop and Mann 2012).
- Full Text:
- Date Issued: 2016
Aggregation control of robust water-soluble zinc (II) phthalocyanine-based photosensitizers
- Ikeuchi, Takuro, Mack, John, Nyokong, Tebello, Kobayashi, Nagao, Kimura, Mutsumi
- Authors: Ikeuchi, Takuro , Mack, John , Nyokong, Tebello , Kobayashi, Nagao , Kimura, Mutsumi
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239709 , vital:50757 , xlink:href="https://doi.org/10.1021/acs.langmuir.6b03552"
- Description: A water-soluble zinc phthalocyanine (ZnPc) complex with four negatively charged electron-withdrawing sulfonic acid substituents at the nonperipheral positions (α-ZnTSPc) is found to have a high singlet oxygen (1O2) quantum yield and exhibits high photostability. The formation of aggregates is hindered and the highest occupied molecular orbital is significantly stabilized, making α-ZnTSPc potentially suitable for its use as a photosensitizer for photodynamic therapy and photoimmunotherapy. Atomic force microscopy (AFM) reveals that mixtures of the negatively charged α-ZnTSPc complex with a similar positively charged ZnPc were found to result in the self-assembly of one-dimensional accordion-like fibers. Supramolecular fibers can be formed in aqueous solutions through intermolecular electrostatic and donor–acceptor interactions between the two water-soluble ZnPcs.
- Full Text:
- Date Issued: 2016
- Authors: Ikeuchi, Takuro , Mack, John , Nyokong, Tebello , Kobayashi, Nagao , Kimura, Mutsumi
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239709 , vital:50757 , xlink:href="https://doi.org/10.1021/acs.langmuir.6b03552"
- Description: A water-soluble zinc phthalocyanine (ZnPc) complex with four negatively charged electron-withdrawing sulfonic acid substituents at the nonperipheral positions (α-ZnTSPc) is found to have a high singlet oxygen (1O2) quantum yield and exhibits high photostability. The formation of aggregates is hindered and the highest occupied molecular orbital is significantly stabilized, making α-ZnTSPc potentially suitable for its use as a photosensitizer for photodynamic therapy and photoimmunotherapy. Atomic force microscopy (AFM) reveals that mixtures of the negatively charged α-ZnTSPc complex with a similar positively charged ZnPc were found to result in the self-assembly of one-dimensional accordion-like fibers. Supramolecular fibers can be formed in aqueous solutions through intermolecular electrostatic and donor–acceptor interactions between the two water-soluble ZnPcs.
- Full Text:
- Date Issued: 2016
Allelopathic effects of Lantana camara on indigenous forest species in South Africa
- Ruwanza, Sheunesu, Shackleton, Charlie M
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182296 , vital:43818 , xlink:href="http://www.allelopathyjournal.org/?"
- Description: Lantana camara, is an invasive plant in South Africa and greatly influences the forest spp. In greenhouse, we evaluated the allelopathic effects of aqueous extracts of L. camara leaf, stem and root on 5-test species, (3-forest species viz., Acacia natalitia, Kiggalaria africana and Searsia crenata and 2-crops: Solanum lycopersicum and Lactuca sativa). Potential allelopathic compounds present in L. camara leaf, stem and root aqueous extracts were identified using gas chromatography mass spectrometry (GC-MS). The leaf, stem and root aqueous extracts of L. camara reduced the seed germination and seedling growth of all test species showing that L. camara aqueous extracts were deleterious to all test species. We identified 92 major volatile organic components in L. camara aqueous extracts. These compounds had the potential to inhibit the germination and seedling growth of test crops. The leaf, stem and root aqueous extracts of L. camara contained the allelopathic compounds that inhibited the germination and seedling growth of indigenous forest species and crop species.
- Full Text:
- Date Issued: 2016
- Authors: Ruwanza, Sheunesu , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182296 , vital:43818 , xlink:href="http://www.allelopathyjournal.org/?"
- Description: Lantana camara, is an invasive plant in South Africa and greatly influences the forest spp. In greenhouse, we evaluated the allelopathic effects of aqueous extracts of L. camara leaf, stem and root on 5-test species, (3-forest species viz., Acacia natalitia, Kiggalaria africana and Searsia crenata and 2-crops: Solanum lycopersicum and Lactuca sativa). Potential allelopathic compounds present in L. camara leaf, stem and root aqueous extracts were identified using gas chromatography mass spectrometry (GC-MS). The leaf, stem and root aqueous extracts of L. camara reduced the seed germination and seedling growth of all test species showing that L. camara aqueous extracts were deleterious to all test species. We identified 92 major volatile organic components in L. camara aqueous extracts. These compounds had the potential to inhibit the germination and seedling growth of test crops. The leaf, stem and root aqueous extracts of L. camara contained the allelopathic compounds that inhibited the germination and seedling growth of indigenous forest species and crop species.
- Full Text:
- Date Issued: 2016
Alzheimer’s disease: making sense of the stress
- Authors: Whiteley, Chris G
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/67072 , vital:29029 , http://www.smgebooks.com/alzheimers-disease/chapters/ALZD-16-08.pdf
- Description: publisher version , To facilitate a deep understanding of the mechanisms involved in neurodegeneration and Alzheimer’s disease fundamental knowledge is required about the action and function of enzymes in the brain that not only metabolise arginine (neuronal nitric oxide synthase) but are closely associated with oxidative (superoxide dismutase; catalase; glutathione peroxidase) and/or nitrosative stress. In particular the focus extends towards enzymes that contribute to amyloid peptide aggregation and senile plaquedeposits (fibrillogenesis). Of special importance are the glycine zipper regions within these amyloid peptides, especially Aβ25-29 and Aβ29-33 (that contains two isoleucine residues) and the pentapeptide Aβ17-21 (that contains two phenylalanines), each generated by enzymatic cleavage of the intramembrane amyloid precursor protein. Use of antisense-sense technology has identified regions in each enzyme that are capable of binding with the amyloid peptides. After an initial inhibition of each enzyme there is an oligomerisation into soluble fibrils which accumulate and eventually precipitate. The use of nanoparticles do not just prevent but reverse the formation of these fibrils either by disrupting the binary adduct – enzyme-Aβ-peptide- or by reaction with, and therefore deplete, Aβ-monomers in solution and so block potential aggregation sites on the enzyme itself. Future therapy towards Alzheimer’s disease should target the C-terminal region of the amyloid precursor protein and substitute hydrophobic residues for the glycine amino acids within the glycine zipper region.
- Full Text:
- Date Issued: 2016
- Authors: Whiteley, Chris G
- Date: 2016
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/67072 , vital:29029 , http://www.smgebooks.com/alzheimers-disease/chapters/ALZD-16-08.pdf
- Description: publisher version , To facilitate a deep understanding of the mechanisms involved in neurodegeneration and Alzheimer’s disease fundamental knowledge is required about the action and function of enzymes in the brain that not only metabolise arginine (neuronal nitric oxide synthase) but are closely associated with oxidative (superoxide dismutase; catalase; glutathione peroxidase) and/or nitrosative stress. In particular the focus extends towards enzymes that contribute to amyloid peptide aggregation and senile plaquedeposits (fibrillogenesis). Of special importance are the glycine zipper regions within these amyloid peptides, especially Aβ25-29 and Aβ29-33 (that contains two isoleucine residues) and the pentapeptide Aβ17-21 (that contains two phenylalanines), each generated by enzymatic cleavage of the intramembrane amyloid precursor protein. Use of antisense-sense technology has identified regions in each enzyme that are capable of binding with the amyloid peptides. After an initial inhibition of each enzyme there is an oligomerisation into soluble fibrils which accumulate and eventually precipitate. The use of nanoparticles do not just prevent but reverse the formation of these fibrils either by disrupting the binary adduct – enzyme-Aβ-peptide- or by reaction with, and therefore deplete, Aβ-monomers in solution and so block potential aggregation sites on the enzyme itself. Future therapy towards Alzheimer’s disease should target the C-terminal region of the amyloid precursor protein and substitute hydrophobic residues for the glycine amino acids within the glycine zipper region.
- Full Text:
- Date Issued: 2016
An analysis of grade 12 students' attitudes towards agriculture as a career choice in Nkonkobe municipality, Eastern Cape
- Authors: Ndema, Tenjiwe N
- Date: 2016
- Subjects: Career development -- South Africa , Agriculture -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26592 , vital:65661
- Description: In South Africa there is a perception that the youth, particularly black youth, lack interest in agriculture as a career. The youth are perceived to be more drawn to white collar jobs, because they believe that these jobs are more pleasant and better paying. The literature moreover suggests that the youth perceive agriculture as dirty work which is more appropriate for uneducated or illiterate people. The main aim of the research was to analyse Grade12 students’ attitudes towards agriculture as a career choice in Nkonkobe Municipality. Students from four high schools were interviewed using a structured questionnaire, and the total sample size was 100. Based on the results, about one third of students have a favorable perception of agriculture as a career choice, which is more than what had been expected based on the literature reviewed. Both students from non-agricultural schools and agricultural schools possess a positive attitude towards agriculture. They indicated that agriculture offers a lot of financial gain, is not necessarily associated with poverty, nor is agriculture widely regarded as a last resort for those who have failed in other careers. Moreover, they believe that agriculture is as important as other sectors. However, of those learners who indicated an intention to pursue agriculture as a career, only 1 % specifically wished to become a farmer. The others rather wanted professional careers within the agricultural sector, such as veterinarians, agricultural economists, and so forth. Their interest in agriculture as a career related in large measure to a desire to live in a rural area and work with their hands; however this did not extend to actual farming. , Thesis (M Agric) -- Faculty of Science and Agriculture, 2016
- Full Text:
- Date Issued: 2016
- Authors: Ndema, Tenjiwe N
- Date: 2016
- Subjects: Career development -- South Africa , Agriculture -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26592 , vital:65661
- Description: In South Africa there is a perception that the youth, particularly black youth, lack interest in agriculture as a career. The youth are perceived to be more drawn to white collar jobs, because they believe that these jobs are more pleasant and better paying. The literature moreover suggests that the youth perceive agriculture as dirty work which is more appropriate for uneducated or illiterate people. The main aim of the research was to analyse Grade12 students’ attitudes towards agriculture as a career choice in Nkonkobe Municipality. Students from four high schools were interviewed using a structured questionnaire, and the total sample size was 100. Based on the results, about one third of students have a favorable perception of agriculture as a career choice, which is more than what had been expected based on the literature reviewed. Both students from non-agricultural schools and agricultural schools possess a positive attitude towards agriculture. They indicated that agriculture offers a lot of financial gain, is not necessarily associated with poverty, nor is agriculture widely regarded as a last resort for those who have failed in other careers. Moreover, they believe that agriculture is as important as other sectors. However, of those learners who indicated an intention to pursue agriculture as a career, only 1 % specifically wished to become a farmer. The others rather wanted professional careers within the agricultural sector, such as veterinarians, agricultural economists, and so forth. Their interest in agriculture as a career related in large measure to a desire to live in a rural area and work with their hands; however this did not extend to actual farming. , Thesis (M Agric) -- Faculty of Science and Agriculture, 2016
- Full Text:
- Date Issued: 2016