Unsymmetrically substituted nickel triazatetra-benzcorrole and phthalocynanine complexes
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
- Full Text:
- Date Issued: 2014
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
- Full Text:
- Date Issued: 2014
Understanding the replication biology of Providence virus: elucidating the function of non-structural proteins
- Authors: Nakayinga, Ritah
- Date: 2014
- Subjects: Insects Viruses , Viruses Reproduction , Tombusviridae , RNA viruses , RNA polymerases
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193930 , vital:45408
- Description: Tetraviruses are non-enveloped, small insect RNA viruses with a single stranded positive RNA genome that is either monopartite or bipartite. Providence virus (PrV) is the only member of the three tetravirus families with a viral replicase similar to the replicases of tombusviruses and umbraviruses. The principle aim of this thesis was to study PrV replication, focusing on subcellular localization and potential interactions between PrV replication proteins. The first objective of this study was to generate an anti-p104 antibody that does not cross-react with p40. Expression of the C-terminal portion of p104 in E. coli resulted in no detectable protein. Further expression in an insect cell based expression system resulted in the production of an insoluble protein. Attempts to improve protein solubility with a range of solubilization treatments were unsuccessful. Bioinformatic analysis was used to detect an antigenic region at the C-terminus of p104 and the peptide was used to raise anti-p104 antibodies. These antibodies did not detect native protein by western blot detection however they were used for immunoprecipitation. The establishment of the subcellular localization of PrV required two approaches; immunofluorescence in persistently infected Helicoverpa zea MG8 cells using antip40 and anti-dsRNA antibodies and the expression of EGFP-replicase fusion protein in Spodoptera frugiperda Sf9 cells. Replication of PrV was found to take place in cytosolic punctate structures. Co-immunoprecipitation experiments revealed that p40 self-interacts and interacts with p104. Bioinformatic analysis of PrV p104 suggests that the RdRp is similar to viral RdRps of the carmo-like supergroup II. Potential RNA binding regions are present within p104. A potential p40 interaction domain that shares hydrophilic and surface exposed properties with the TBSV p33 interaction domain is present. A putative arginine-rich region and disordered C-terminal region is present in p130. In conclusion, PrV p104 is the viral replicase. The resemblance of the expression strategy and putative functional domains with tombusviruses and umbraviruses suggest that PrV replication is related to the replication system of the tombusviruses and umbraviruses. This has led to propose that tetravirus replication strategies are diverse and raises questions on the origin and evolution of PrV. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
- Full Text:
- Date Issued: 2014
- Authors: Nakayinga, Ritah
- Date: 2014
- Subjects: Insects Viruses , Viruses Reproduction , Tombusviridae , RNA viruses , RNA polymerases
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/193930 , vital:45408
- Description: Tetraviruses are non-enveloped, small insect RNA viruses with a single stranded positive RNA genome that is either monopartite or bipartite. Providence virus (PrV) is the only member of the three tetravirus families with a viral replicase similar to the replicases of tombusviruses and umbraviruses. The principle aim of this thesis was to study PrV replication, focusing on subcellular localization and potential interactions between PrV replication proteins. The first objective of this study was to generate an anti-p104 antibody that does not cross-react with p40. Expression of the C-terminal portion of p104 in E. coli resulted in no detectable protein. Further expression in an insect cell based expression system resulted in the production of an insoluble protein. Attempts to improve protein solubility with a range of solubilization treatments were unsuccessful. Bioinformatic analysis was used to detect an antigenic region at the C-terminus of p104 and the peptide was used to raise anti-p104 antibodies. These antibodies did not detect native protein by western blot detection however they were used for immunoprecipitation. The establishment of the subcellular localization of PrV required two approaches; immunofluorescence in persistently infected Helicoverpa zea MG8 cells using antip40 and anti-dsRNA antibodies and the expression of EGFP-replicase fusion protein in Spodoptera frugiperda Sf9 cells. Replication of PrV was found to take place in cytosolic punctate structures. Co-immunoprecipitation experiments revealed that p40 self-interacts and interacts with p104. Bioinformatic analysis of PrV p104 suggests that the RdRp is similar to viral RdRps of the carmo-like supergroup II. Potential RNA binding regions are present within p104. A potential p40 interaction domain that shares hydrophilic and surface exposed properties with the TBSV p33 interaction domain is present. A putative arginine-rich region and disordered C-terminal region is present in p130. In conclusion, PrV p104 is the viral replicase. The resemblance of the expression strategy and putative functional domains with tombusviruses and umbraviruses suggest that PrV replication is related to the replication system of the tombusviruses and umbraviruses. This has led to propose that tetravirus replication strategies are diverse and raises questions on the origin and evolution of PrV. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
- Full Text:
- Date Issued: 2014
Understanding food security in a perfect storm: an ecosystem services approach
- Poppy, G M, Chiotha, S, Eigenbrod, Felix, Harvey, Celia A, Honza´k, M, Hudson, Malcolm D, Jarvis, A, Madise, Nyovani J, Schreckenberg, Kate, Shackleton, Charlie M, Villa, F, Dawson, Terrence P
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, F , Dawson, Terrence P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Date Issued: 2014
- Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, F , Dawson, Terrence P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
- Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
- Full Text:
- Date Issued: 2014
Trends in the TD-DFT calculations of porphyrin and phthalocyanine analogs
- Mack, John, Stone, Justin, Nyokong, Tebello
- Authors: Mack, John , Stone, Justin , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193882 , vital:45402 , xlink:href="https://doi.org/10.1142/S108842461450045X"
- Description: In 2005, Kobayashi and coworkers reported trends in the TD-DFT spectra of 17 Zn (II) porphyrinoids [J. Am. Chem. Soc. 2005; 127: 17697] that were analyzed using Michl's perimeter model as part of a study of the anomalous magnetic circular dichroism (MCD) spectroscopy of zinc tetraphenyltetraacenaphthoporphyrin. In recent years, it has become increasingly clear that TD-DFT calculations with the commonly used hybrid B3LYP exchange-correlation functional of the Gaussian software package are problematic in the B-band region of porphyrinoid spectra, since the degree of configurational interaction between the B and higher energy ππ* state appears to be significantly overestimated. The CAM-B3LYP functional is now often preferred for analyzing the optical properties of porphyrinoids, since it includes a long-range correction of the exchange potential, which incorporates an increasing fraction of Hartree–Fock (HF) exchange as the interelectronic separation increases, making it better suited for studying compounds where there is significant charge transfer in the electronic excited states. The trends in the TD-DFT calculations are reexamined with a wider range porphyrinoid compounds including several with pyrazino moieties and are found to provide a closer agreement with the experimental in the B-band region for complexes such as zinc tetraphenylporphyrin and phthalocyanine.
- Full Text:
- Date Issued: 2014
- Authors: Mack, John , Stone, Justin , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193882 , vital:45402 , xlink:href="https://doi.org/10.1142/S108842461450045X"
- Description: In 2005, Kobayashi and coworkers reported trends in the TD-DFT spectra of 17 Zn (II) porphyrinoids [J. Am. Chem. Soc. 2005; 127: 17697] that were analyzed using Michl's perimeter model as part of a study of the anomalous magnetic circular dichroism (MCD) spectroscopy of zinc tetraphenyltetraacenaphthoporphyrin. In recent years, it has become increasingly clear that TD-DFT calculations with the commonly used hybrid B3LYP exchange-correlation functional of the Gaussian software package are problematic in the B-band region of porphyrinoid spectra, since the degree of configurational interaction between the B and higher energy ππ* state appears to be significantly overestimated. The CAM-B3LYP functional is now often preferred for analyzing the optical properties of porphyrinoids, since it includes a long-range correction of the exchange potential, which incorporates an increasing fraction of Hartree–Fock (HF) exchange as the interelectronic separation increases, making it better suited for studying compounds where there is significant charge transfer in the electronic excited states. The trends in the TD-DFT calculations are reexamined with a wider range porphyrinoid compounds including several with pyrazino moieties and are found to provide a closer agreement with the experimental in the B-band region for complexes such as zinc tetraphenylporphyrin and phthalocyanine.
- Full Text:
- Date Issued: 2014
The role of records management in the sustainability of small micro medium enterprises (SMMEs) in the Eastern Cape, South Africa: a study of Alice and Fort Beaufort
- Ajibade, Patrick https://orcid.org/0000-0002-8608-8378
- Authors: Ajibade, Patrick https://orcid.org/0000-0002-8608-8378
- Date: 2014
- Subjects: Knowledge management , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25259 , vital:64122
- Description: The study sought to investigate the role of records management in the sustainability of the Small Micro, Medium enterprises (SMMEs) in the Eastern Cape Province of South Africa with focus on Alice and Fort Beaufort towns. The objectives of the study were to identify the types of records that are kept by SMMEs; evaluate the infrastructure for the SMMEs records management; determine the compliance of SMMEs with the existing RM legal and regulatory requirements; and identify the challenges related to SMMEs records practices. Twenty three (23) respondents from SMMEs were interviewed. Findings revealed all the respondents could not confirm adoption of any systemic way of records management to support business functions and operations. Majority of the SMMEs due to their inability to maintain records could not identify potential benefit of business RM with an exception of three SMMEs. The respondents were not aware of any compliance and regulatory framework most especially on business records management. The challenges facing SMMEs include; inability to capture/create maintain, preserve business records systematically in its lifecycle. The SMMEs lack needed training especially in records management to allow them the benefit of maintaining business records. It is recommended that SMMEs should acquire skill that would enable them manage their business records that may help improved decision making. There should be legislative and regulatory framework that ensures compliance. And assistance should be rendered to train SMMEs on basic RM skills that could improve their business operations. , Thesis (MLIS) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014
- Authors: Ajibade, Patrick https://orcid.org/0000-0002-8608-8378
- Date: 2014
- Subjects: Knowledge management , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25259 , vital:64122
- Description: The study sought to investigate the role of records management in the sustainability of the Small Micro, Medium enterprises (SMMEs) in the Eastern Cape Province of South Africa with focus on Alice and Fort Beaufort towns. The objectives of the study were to identify the types of records that are kept by SMMEs; evaluate the infrastructure for the SMMEs records management; determine the compliance of SMMEs with the existing RM legal and regulatory requirements; and identify the challenges related to SMMEs records practices. Twenty three (23) respondents from SMMEs were interviewed. Findings revealed all the respondents could not confirm adoption of any systemic way of records management to support business functions and operations. Majority of the SMMEs due to their inability to maintain records could not identify potential benefit of business RM with an exception of three SMMEs. The respondents were not aware of any compliance and regulatory framework most especially on business records management. The challenges facing SMMEs include; inability to capture/create maintain, preserve business records systematically in its lifecycle. The SMMEs lack needed training especially in records management to allow them the benefit of maintaining business records. It is recommended that SMMEs should acquire skill that would enable them manage their business records that may help improved decision making. There should be legislative and regulatory framework that ensures compliance. And assistance should be rendered to train SMMEs on basic RM skills that could improve their business operations. , Thesis (MLIS) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014
The role of decent rural employment in counteracting food insecurity in Bindura rural district, Zimbabwe
- Authors: Chimberengwa, Patronella
- Date: 2014
- Subjects: Poverty -- Prevention , Food security , Food relief
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26324 , vital:65238
- Description: Despite many initiatives that are being implemented by the governments of different nations and the international community to minimize hunger and poverty in rural areas, several households continue to suffer from food insecurity. The World Food Programme (WFP) and the government in Zimbabwe are providing food aid to approximately 1.6 million people across the 37 districts in the country. Measures have been undertaken to counter food insecurity in Zimbabwe but to no avail. Food related public policies such as donor aid and government subsidies have also been unworkable for such a long time. In this study a comprehensive analysis of the role of decent rural employment in counteracting food insecurity will be provided. The study also seeks to assess how humanitarian work psychologists can work together with various stakeholders in society so as to curb household food insecurity. The Study population included all the households in Bindura rural district in Zimbabwe. Both quantitative and qualitative research designs were used. The researcher used cluster sampling procedure in which households were divided into groups (clusters) and a sample of the groups was selected. A random sample was then drawn from the elements within each selected group. The results confirmed that those that are not decently employed face a broad range of decent work deficits, exploitation at work and are food insecure, a finding that is similar to other countries. Thus, the researcher concluded that Decent Rural employment do have an impact on food security. Taking a look at the basic tenets of decent employment such as full time employment, a decent income, reasonable working hours and employee benefits among others, the results showed that they all impact on food security. The information obtained will be fundamental for communities at risk and dealing with the issue may help improve food insecurity situation in the country. This information will also help in formulating special measures in the form of tailor made strategies specifically made for the district and helps in doing away with what is called a one size fits all approach to food security as it pays particular attention to the households in that particular district. , Thesis (MA) -- Faculty of Management and Commerce, 2014
- Full Text:
- Date Issued: 2014
- Authors: Chimberengwa, Patronella
- Date: 2014
- Subjects: Poverty -- Prevention , Food security , Food relief
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26324 , vital:65238
- Description: Despite many initiatives that are being implemented by the governments of different nations and the international community to minimize hunger and poverty in rural areas, several households continue to suffer from food insecurity. The World Food Programme (WFP) and the government in Zimbabwe are providing food aid to approximately 1.6 million people across the 37 districts in the country. Measures have been undertaken to counter food insecurity in Zimbabwe but to no avail. Food related public policies such as donor aid and government subsidies have also been unworkable for such a long time. In this study a comprehensive analysis of the role of decent rural employment in counteracting food insecurity will be provided. The study also seeks to assess how humanitarian work psychologists can work together with various stakeholders in society so as to curb household food insecurity. The Study population included all the households in Bindura rural district in Zimbabwe. Both quantitative and qualitative research designs were used. The researcher used cluster sampling procedure in which households were divided into groups (clusters) and a sample of the groups was selected. A random sample was then drawn from the elements within each selected group. The results confirmed that those that are not decently employed face a broad range of decent work deficits, exploitation at work and are food insecure, a finding that is similar to other countries. Thus, the researcher concluded that Decent Rural employment do have an impact on food security. Taking a look at the basic tenets of decent employment such as full time employment, a decent income, reasonable working hours and employee benefits among others, the results showed that they all impact on food security. The information obtained will be fundamental for communities at risk and dealing with the issue may help improve food insecurity situation in the country. This information will also help in formulating special measures in the form of tailor made strategies specifically made for the district and helps in doing away with what is called a one size fits all approach to food security as it pays particular attention to the households in that particular district. , Thesis (MA) -- Faculty of Management and Commerce, 2014
- Full Text:
- Date Issued: 2014
the programmable bride
- Authors: Krueger, Anton
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229698 , vital:49701 , xlink:href="https://hdl.handle.net/10520/EJC156969"
- Description: the man gently opens his machine and finding an agreeable port for his firm flash, he eagerly installs the software he's been waiting on for so very long... once booted up, the man takes his first tentative steps, finding his bride perfect in every way, already completely in love with him, and dreamy... the man tenderly reaches out for her-she understands him so well, she's concerned about his needs, she wants to know how he feels, wants only to please him, she only-/but-there's an interruption/somebody's on the stairs, someone's knocking at his door-the man is forced to close her down a little too abruptly, shutting the machine to attend to other matters while he's away he can't wait to get back, he thinks about her all the time; he longs to flip his laptop lid up, to open her again... but when finally he silently prises open the instrument of his heart's desires, she seems a little disorientated... he didn't shut her down properly …
- Full Text:
- Date Issued: 2014
- Authors: Krueger, Anton
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229698 , vital:49701 , xlink:href="https://hdl.handle.net/10520/EJC156969"
- Description: the man gently opens his machine and finding an agreeable port for his firm flash, he eagerly installs the software he's been waiting on for so very long... once booted up, the man takes his first tentative steps, finding his bride perfect in every way, already completely in love with him, and dreamy... the man tenderly reaches out for her-she understands him so well, she's concerned about his needs, she wants to know how he feels, wants only to please him, she only-/but-there's an interruption/somebody's on the stairs, someone's knocking at his door-the man is forced to close her down a little too abruptly, shutting the machine to attend to other matters while he's away he can't wait to get back, he thinks about her all the time; he longs to flip his laptop lid up, to open her again... but when finally he silently prises open the instrument of his heart's desires, she seems a little disorientated... he didn't shut her down properly …
- Full Text:
- Date Issued: 2014
The life history traits of the arctiine moth Pareuchaetes insulata, a biological control agent of Chromolaena odorata in South Africa
- Uyi, Osariyekemwen, Zachariades, Costas, Hill, Martin P
- Authors: Uyi, Osariyekemwen , Zachariades, Costas , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406170 , vital:70244 , xlink:href="https://hdl.handle.net/10520/EJC160238"
- Description: Pareuchaetes insulata (Walker) (Lepidoptera: Erebidae: Arctiinae) was released in KwaZulu-Natal, South Africa, as a biological control agent against Chromolaena odorata (L.) King and Robinson (Asteraceae) between 2001 and 2009. Although the moth did establish at one out of some 30 release sites, its population level is generally low in the field. Two closely related biological control agents, P. pseudoinsulata Rego Barros and P. aurata aurata (Butler) had previously failed to establish despite several years of releases. Studies of life history traits of P. insulata (males and females) were conducted to determine whether several aspects of its developmental and reproductive biology can explain its poor performance, and to compare the development and reproductive biology of P. insulata with the two other closely related species. At 25 °C, overall mortality of immature stages was generally low (below 12 %). Although the duration of the larval life stage was statistically longer for females, overall they eclosed as adults before the males (i.e. protogyny). Pupal mass, growth rate and total leaf area consumed were higher in females. Mated females laid 74% of their eggs on the first four nights following eclosion and lived an average of 5.92 ± 0.19 days. The moth also showed good biological attributes such as high fecundity (number of eggs), egg hatchability and female mating success (the number of matings that resulted in fertile eggs). Significant positive correlations were detected between insect performance metrics and leaf consumption and between fecundity and pupal mass. A 23 % greater lifetime reproductive output (387.62 ± 19.50 eggs per female) for P. insulata compared with P. aurata aurata was recorded. We hypothesize that the absence of protandry in P. insulata might have contributed to the low population levels of the moth in the field. The results of this study contribute to our understanding of the life history traits of erebid moths in the subfamily Arctiinae deployed for the biological control of C. odorata.
- Full Text:
- Date Issued: 2014
- Authors: Uyi, Osariyekemwen , Zachariades, Costas , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406170 , vital:70244 , xlink:href="https://hdl.handle.net/10520/EJC160238"
- Description: Pareuchaetes insulata (Walker) (Lepidoptera: Erebidae: Arctiinae) was released in KwaZulu-Natal, South Africa, as a biological control agent against Chromolaena odorata (L.) King and Robinson (Asteraceae) between 2001 and 2009. Although the moth did establish at one out of some 30 release sites, its population level is generally low in the field. Two closely related biological control agents, P. pseudoinsulata Rego Barros and P. aurata aurata (Butler) had previously failed to establish despite several years of releases. Studies of life history traits of P. insulata (males and females) were conducted to determine whether several aspects of its developmental and reproductive biology can explain its poor performance, and to compare the development and reproductive biology of P. insulata with the two other closely related species. At 25 °C, overall mortality of immature stages was generally low (below 12 %). Although the duration of the larval life stage was statistically longer for females, overall they eclosed as adults before the males (i.e. protogyny). Pupal mass, growth rate and total leaf area consumed were higher in females. Mated females laid 74% of their eggs on the first four nights following eclosion and lived an average of 5.92 ± 0.19 days. The moth also showed good biological attributes such as high fecundity (number of eggs), egg hatchability and female mating success (the number of matings that resulted in fertile eggs). Significant positive correlations were detected between insect performance metrics and leaf consumption and between fecundity and pupal mass. A 23 % greater lifetime reproductive output (387.62 ± 19.50 eggs per female) for P. insulata compared with P. aurata aurata was recorded. We hypothesize that the absence of protandry in P. insulata might have contributed to the low population levels of the moth in the field. The results of this study contribute to our understanding of the life history traits of erebid moths in the subfamily Arctiinae deployed for the biological control of C. odorata.
- Full Text:
- Date Issued: 2014
The influence of gold nanoparticles on the electroactivity of nickel tetrasulfonated phthalocyanine
- Maringa, Audacity, Nyokong, Tebello
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189774 , vital:44930 , xlink:href="https://doi.org/10.1142/S1088424614500333"
- Description: We report on the electrodeposition of gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine (NiTSPc) film by electropolymerization (poly-NiTSPc-GCE) to form Poly-NiTSPc/AuNPs-GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔEp) of ferricyanide from 126 mV on poly-NiTSPc to 110 mV on poly-NiTSPc/AuNPs. The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving Ep = 0.78 V and the modified electrodes gave Ep = 0.62 V or 0.61 V. Poly-NiTSPc/AuNPs-GCE had higher currents compared to poly-NiTSPc-GCE. This indicates the enhancement effect caused by the AuNPs. Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly-NiTSPc/AuNPs-GCE was a better electrocatalyst than poly-NiTSPc-GCE or AuNPs-GCE.
- Full Text:
- Date Issued: 2014
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189774 , vital:44930 , xlink:href="https://doi.org/10.1142/S1088424614500333"
- Description: We report on the electrodeposition of gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine (NiTSPc) film by electropolymerization (poly-NiTSPc-GCE) to form Poly-NiTSPc/AuNPs-GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔEp) of ferricyanide from 126 mV on poly-NiTSPc to 110 mV on poly-NiTSPc/AuNPs. The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving Ep = 0.78 V and the modified electrodes gave Ep = 0.62 V or 0.61 V. Poly-NiTSPc/AuNPs-GCE had higher currents compared to poly-NiTSPc-GCE. This indicates the enhancement effect caused by the AuNPs. Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly-NiTSPc/AuNPs-GCE was a better electrocatalyst than poly-NiTSPc-GCE or AuNPs-GCE.
- Full Text:
- Date Issued: 2014
The impact of manufacturing variables on in vitro release of clobetasol 17-propionate from pilot scale cream formulations
- Fauzee, Ayesha F B, Khamanga, Sandile M, Walker, Roderick B
- Authors: Fauzee, Ayesha F B , Khamanga, Sandile M , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183872 , vital:44077 , xlink:href="https://doi.org/10.3109/03639045.2013.842579"
- Description: The purpose of the study was to evaluate the effect of different homogenization speeds and times, anchor speeds and cooling times on the viscosity and cumulative % clobetasol 17-propionate released per unit area at 72 h from pilot scale cream formulations. A 24 full factorial central composite design for four independent variables were investigated. Thirty pilot scale batches of cream formulations were manufactured using a Wintech® cream/ointment plant. The viscosity and in vitro release of CP were monitored and compared to an innovator product that is commercially available on the South African market, namely, Dermovate® cream. Contour and three-dimensional response surface plots were produced and the viscosity and cumulative % CP released per unit area at 72 h were found to be primarily dependent on the homogenization and anchor speeds. An increase in the homogenization and anchor speeds appeared to exhibit a synergistic effect on the resultant viscosity of the cream whereas an antagonistic effect was observed for the in vitro release of CP from the experimental cream formulations. The in vitro release profiles were best fitted to a Higuchi model and diffusion proved to be the dominant mechanism of drug release that was confirmed by use of the Korsmeyer–Peppas model. The research was further validated and confirmed by the high prognostic ability of response surface methodology (RSM) with a resultant mean percentage error of (±SD) 0.17 ± 0.093 suggesting that RSM may be an efficient tool for the development and optimization of topical formulations.
- Full Text:
- Date Issued: 2014
- Authors: Fauzee, Ayesha F B , Khamanga, Sandile M , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183872 , vital:44077 , xlink:href="https://doi.org/10.3109/03639045.2013.842579"
- Description: The purpose of the study was to evaluate the effect of different homogenization speeds and times, anchor speeds and cooling times on the viscosity and cumulative % clobetasol 17-propionate released per unit area at 72 h from pilot scale cream formulations. A 24 full factorial central composite design for four independent variables were investigated. Thirty pilot scale batches of cream formulations were manufactured using a Wintech® cream/ointment plant. The viscosity and in vitro release of CP were monitored and compared to an innovator product that is commercially available on the South African market, namely, Dermovate® cream. Contour and three-dimensional response surface plots were produced and the viscosity and cumulative % CP released per unit area at 72 h were found to be primarily dependent on the homogenization and anchor speeds. An increase in the homogenization and anchor speeds appeared to exhibit a synergistic effect on the resultant viscosity of the cream whereas an antagonistic effect was observed for the in vitro release of CP from the experimental cream formulations. The in vitro release profiles were best fitted to a Higuchi model and diffusion proved to be the dominant mechanism of drug release that was confirmed by use of the Korsmeyer–Peppas model. The research was further validated and confirmed by the high prognostic ability of response surface methodology (RSM) with a resultant mean percentage error of (±SD) 0.17 ± 0.093 suggesting that RSM may be an efficient tool for the development and optimization of topical formulations.
- Full Text:
- Date Issued: 2014
The herbivorous arthropods associated with the invasive alien plant, Arundo donax, and the native analogous plant, Phragmites australis, in the Free State Province, South Africa s
- Canavan, Kim N, Paterson, Iain D, Hill, Martin P
- Authors: Canavan, Kim N , Paterson, Iain D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406155 , vital:70243 , xlink:href="https://hdl.handle.net/10520/EJC155690"
- Description: The Enemy Release Hypothesis (ERH) predicts that when plant species are introduced outside their native range there is a release from natural enemies resulting in the plants becoming problematic invasive alien species (Lake and Leishman 2004; Puliafico et al. 2008). The release from natural enemies may benefit alien plants more than simply reducing herbivory because, according to the Evolution of Increased Competitive Ability (EICA) hypothesis, without pressure from herbivores more resources that were previously allocated to defence can be allocated to reproduction (Blossey and Notzold 1995). Alien invasive plants are therefore expected to have simpler herbivore communities with fewer specialist herbivores (Frenzel and Brandl 2003; Heleno et al. 2008; Heger and Jeschke 2014).
- Full Text:
- Date Issued: 2014
- Authors: Canavan, Kim N , Paterson, Iain D , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406155 , vital:70243 , xlink:href="https://hdl.handle.net/10520/EJC155690"
- Description: The Enemy Release Hypothesis (ERH) predicts that when plant species are introduced outside their native range there is a release from natural enemies resulting in the plants becoming problematic invasive alien species (Lake and Leishman 2004; Puliafico et al. 2008). The release from natural enemies may benefit alien plants more than simply reducing herbivory because, according to the Evolution of Increased Competitive Ability (EICA) hypothesis, without pressure from herbivores more resources that were previously allocated to defence can be allocated to reproduction (Blossey and Notzold 1995). Alien invasive plants are therefore expected to have simpler herbivore communities with fewer specialist herbivores (Frenzel and Brandl 2003; Heleno et al. 2008; Heger and Jeschke 2014).
- Full Text:
- Date Issued: 2014
The extent and perceptions of vandalism as a cause of street tree damage in small towns in the Eastern Cape, South Africa
- Richardson, Emma, Shackleton, Charlie M
- Authors: Richardson, Emma , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180954 , vital:43676 , xlink:href="https://doi.org/10.1016/j.ufug.2014.04.003"
- Description: Street trees are important foundations of urban sustainability due to the ecosystem services that they provide society and the environment. However, street trees are vulnerable to vandalism and damage, especially when small, which constraints the flow of benefits they provide and also increases the costs of planting programmes. Despite being a common phenomenon, there is limited knowledge regarding the extent of vandalism and the reasons for it. Here we seek to understand the causes and extent of street tree damage in eleven small Eastern Cape (South Africa) towns and to assess the perceptions of residents and officials. The condition of newly planted street trees was assessed in each town and residents were interviewed in the two towns with the highest number of newly planted street trees. Almost half (42%) of recently planted street trees were totally snapped, ranging between 0% and 63% per town. There was no difference in the prevalence of trees being snapped between those with protective structures and those without. Each town used different structures around newly planted street trees, but in only two towns were all the structures intact. The prevalence of damage declined with increasing trunk thickness and increasing town size. According to residents, boredom, misbehaviour, lack of appreciation of trees and collection for wood were the main factors for tree vandalism by people along with damage by livestock. Ward councillors recognised the presence of vandalism, but indicated that it was not a priority topic in their ward meetings. Suggestions by residents to prevent vandalism included: planting in sensible areas, re-designing the protective structures, re-locating livestock and engendering community participation and ownership in all aspects of street tree planting.
- Full Text:
- Date Issued: 2014
- Authors: Richardson, Emma , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180954 , vital:43676 , xlink:href="https://doi.org/10.1016/j.ufug.2014.04.003"
- Description: Street trees are important foundations of urban sustainability due to the ecosystem services that they provide society and the environment. However, street trees are vulnerable to vandalism and damage, especially when small, which constraints the flow of benefits they provide and also increases the costs of planting programmes. Despite being a common phenomenon, there is limited knowledge regarding the extent of vandalism and the reasons for it. Here we seek to understand the causes and extent of street tree damage in eleven small Eastern Cape (South Africa) towns and to assess the perceptions of residents and officials. The condition of newly planted street trees was assessed in each town and residents were interviewed in the two towns with the highest number of newly planted street trees. Almost half (42%) of recently planted street trees were totally snapped, ranging between 0% and 63% per town. There was no difference in the prevalence of trees being snapped between those with protective structures and those without. Each town used different structures around newly planted street trees, but in only two towns were all the structures intact. The prevalence of damage declined with increasing trunk thickness and increasing town size. According to residents, boredom, misbehaviour, lack of appreciation of trees and collection for wood were the main factors for tree vandalism by people along with damage by livestock. Ward councillors recognised the presence of vandalism, but indicated that it was not a priority topic in their ward meetings. Suggestions by residents to prevent vandalism included: planting in sensible areas, re-designing the protective structures, re-locating livestock and engendering community participation and ownership in all aspects of street tree planting.
- Full Text:
- Date Issued: 2014
The ethical function of research and teaching
- Authors: Tabensky, Pedro
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305738 , vital:58608 , xlink:href="https://doi.org/10.1111/j.1469-5812.2011.00813.x"
- Description: It is the epistemic as well as the ethical responsibility of academics to aim to approach their research and teaching with a proper understanding of the ultimate ethical purpose or telos of their defining activities and products,which is the practical aim of promoting human flourishing. Minimally, academics should aim at understanding, and a key component of understanding is to understand the ideal ethical purpose of what is being researched and taught. For instance, sadistic Nazi medical researchers and teachers—Mengeles of sorts—in addition to having reprehensible commitments,would be significantly ignorant about their own intellectual concerns by virtue of their abject (belief-expressing) commitments. I will show that insights drawn from extreme cases such as this one apply across disciplines and in less extreme cases.
- Full Text:
- Date Issued: 2014
- Authors: Tabensky, Pedro
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305738 , vital:58608 , xlink:href="https://doi.org/10.1111/j.1469-5812.2011.00813.x"
- Description: It is the epistemic as well as the ethical responsibility of academics to aim to approach their research and teaching with a proper understanding of the ultimate ethical purpose or telos of their defining activities and products,which is the practical aim of promoting human flourishing. Minimally, academics should aim at understanding, and a key component of understanding is to understand the ideal ethical purpose of what is being researched and taught. For instance, sadistic Nazi medical researchers and teachers—Mengeles of sorts—in addition to having reprehensible commitments,would be significantly ignorant about their own intellectual concerns by virtue of their abject (belief-expressing) commitments. I will show that insights drawn from extreme cases such as this one apply across disciplines and in less extreme cases.
- Full Text:
- Date Issued: 2014
The effects of extracellular and intracellular Hop on cell migration processes
- Authors: Contu, Lara
- Date: 2014
- Subjects: Heat shock proteins , Metastasis , Cancer Chemotherapy , Molecular chaperones , Cell migration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193961 , vital:45410
- Description: The Hsp70/Hsp90-organising protein (Hop) is a 60 kDa co-chaperone that acts as an adaptor molecule, facilitating the transfer of client proteins between the Hsp70 and Hsp90 chaperone systems. Hop functions both intracellularly and extracellularly and has been implicated in many processes involved in cancer progression, including cell migration and invasion. Little is known about the mechanisms or domains by which extracellular Hop functions. In addition, little is known about the effects of Hop on signalling molecules involved in cell migration and invasion through regulation of actin dynamics. It was hypothesised that both extracellular and intracellular pools of Hop would regulate distinct cell migration processes by activation of cell signalling pathways or direct interactions with signalling intermediates. HS578T cells were treated with recombinant full length and truncated murine Hop proteins (overexpressed and purified in this study) to determine the effects of extracellular Hop and the independent domains on cell migration processes. Additionally, RNA interference (RNAi) techniques were used to determine the effect of Hop knockdown on cell migration related signalling intermediates and cell morphologies. A short hairpin RNA (shRNA) system for the stable knockdown of Hop was developed and used for a number of these studies. Treatment of HS578T cells with the TPR2A2B and TPR1 domains of Hop resulted in a significant decrease in cell migration and caused changes in the actin cytoskeleton and extracellular matrix proteins, gelatin and fibronectin. RhoC immunoprecipitated in a common complex with Hop and Hsp90. Hop knockdown reduced levels of actin and total RhoC, as well as active RhoC. In addition, knockdown of Hop resulted in a reduced migratory phenotype. We interpreted these data to indicate that intracellular Hop played a role in cell migration through regulation of RhoC activity, either through a direct interaction between Hop and RhoC, or an indirect interaction of RhoC with the Hsp90 multichaperone heterocomplex. Taken together, the data suggested that extracellular and intracellular Hop played distinct roles in extracellular and intracellular processes that lead to actin dynamics and cell migration. Understanding the mechanistic role of Hop in these processes is essential as it would aid in assessing the viability of Hop as a potential drug target for the treatment of metastatic cancers. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
- Full Text:
- Date Issued: 2014
- Authors: Contu, Lara
- Date: 2014
- Subjects: Heat shock proteins , Metastasis , Cancer Chemotherapy , Molecular chaperones , Cell migration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193961 , vital:45410
- Description: The Hsp70/Hsp90-organising protein (Hop) is a 60 kDa co-chaperone that acts as an adaptor molecule, facilitating the transfer of client proteins between the Hsp70 and Hsp90 chaperone systems. Hop functions both intracellularly and extracellularly and has been implicated in many processes involved in cancer progression, including cell migration and invasion. Little is known about the mechanisms or domains by which extracellular Hop functions. In addition, little is known about the effects of Hop on signalling molecules involved in cell migration and invasion through regulation of actin dynamics. It was hypothesised that both extracellular and intracellular pools of Hop would regulate distinct cell migration processes by activation of cell signalling pathways or direct interactions with signalling intermediates. HS578T cells were treated with recombinant full length and truncated murine Hop proteins (overexpressed and purified in this study) to determine the effects of extracellular Hop and the independent domains on cell migration processes. Additionally, RNA interference (RNAi) techniques were used to determine the effect of Hop knockdown on cell migration related signalling intermediates and cell morphologies. A short hairpin RNA (shRNA) system for the stable knockdown of Hop was developed and used for a number of these studies. Treatment of HS578T cells with the TPR2A2B and TPR1 domains of Hop resulted in a significant decrease in cell migration and caused changes in the actin cytoskeleton and extracellular matrix proteins, gelatin and fibronectin. RhoC immunoprecipitated in a common complex with Hop and Hsp90. Hop knockdown reduced levels of actin and total RhoC, as well as active RhoC. In addition, knockdown of Hop resulted in a reduced migratory phenotype. We interpreted these data to indicate that intracellular Hop played a role in cell migration through regulation of RhoC activity, either through a direct interaction between Hop and RhoC, or an indirect interaction of RhoC with the Hsp90 multichaperone heterocomplex. Taken together, the data suggested that extracellular and intracellular Hop played distinct roles in extracellular and intracellular processes that lead to actin dynamics and cell migration. Understanding the mechanistic role of Hop in these processes is essential as it would aid in assessing the viability of Hop as a potential drug target for the treatment of metastatic cancers. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
- Full Text:
- Date Issued: 2014
The effect of sap-sucking by Falconia intermedia (Hemiptera: Miridae) on the emission of volatile organic compounds from the leaves of Lantana camara varieties
- Heshula, Lelethu U, Hill, Martin P
- Authors: Heshula, Lelethu U , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406141 , vital:70242 , xlink:href="https://hdl.handle.net/10520/EJC150957"
- Description: Evidence from more than 100 plant species has confirmed that plants emit volatile organic chemicals (VOC) in response to herbivory (Karban and Baldwin 1997; Dicke et al. 2003; Arimura et al. 2005). Feeding-induced plant responses may result in higher levels of volatiles, and different bouquets of compounds being emitted by plants following herbivore damage (Wei et al. 2006). The emission of volatile chemicals may be beneficial to plants in two ways; undamaged plants may interpret the chemical signals from damaged plants and in turn prime themselves for defence (Arimura et al. 2000; Dicke et al. 2003; Agrawal 2005), or volatiles emitted by damaged plants may attract natural enemies of the herbivores, which may reduce further damage to the plants (Tumlinson et al. 1993; De Moraes et al. 1998; Dicke and Vet 1999).
- Full Text:
- Date Issued: 2014
- Authors: Heshula, Lelethu U , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406141 , vital:70242 , xlink:href="https://hdl.handle.net/10520/EJC150957"
- Description: Evidence from more than 100 plant species has confirmed that plants emit volatile organic chemicals (VOC) in response to herbivory (Karban and Baldwin 1997; Dicke et al. 2003; Arimura et al. 2005). Feeding-induced plant responses may result in higher levels of volatiles, and different bouquets of compounds being emitted by plants following herbivore damage (Wei et al. 2006). The emission of volatile chemicals may be beneficial to plants in two ways; undamaged plants may interpret the chemical signals from damaged plants and in turn prime themselves for defence (Arimura et al. 2000; Dicke et al. 2003; Agrawal 2005), or volatiles emitted by damaged plants may attract natural enemies of the herbivores, which may reduce further damage to the plants (Tumlinson et al. 1993; De Moraes et al. 1998; Dicke and Vet 1999).
- Full Text:
- Date Issued: 2014
The comparative growth rates of indigenous street and garden trees in Grahamstown, South Africa
- De Lacy, Peter J G, Shackleton, Charlie M
- Authors: De Lacy, Peter J G , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180943 , vital:43672 , xlink:href="https://doi.org/10.1016/j.sajb.2014.02.007"
- Description: Urban forestry is advocated worldwide as a means of enhancing the liveability of towns and cities, and mitigating some of the anticipated impacts of climate change. Optimisation of the benefits of trees in urban areas is dependent upon knowledge of tree form, growth, and the products and benefits that trees provide. Growth rates are a vital variable for modelling benefits, yet there is a significant gap in knowledge pertaining to growth rates of trees in urban areas, especially indigenous species in developing world countries. Here we report on growth rates of indigenous street and garden trees in Grahamstown, South Africa, using two approaches; tree ring counts on increment cores and mean rates from trees of known planting age. Growth equations for both street and garden trees were derived. There was no significant difference in mean growth rates determined via the two methods. For both methods street trees grew approximately 30% slower than trees in gardens.
- Full Text:
- Date Issued: 2014
- Authors: De Lacy, Peter J G , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180943 , vital:43672 , xlink:href="https://doi.org/10.1016/j.sajb.2014.02.007"
- Description: Urban forestry is advocated worldwide as a means of enhancing the liveability of towns and cities, and mitigating some of the anticipated impacts of climate change. Optimisation of the benefits of trees in urban areas is dependent upon knowledge of tree form, growth, and the products and benefits that trees provide. Growth rates are a vital variable for modelling benefits, yet there is a significant gap in knowledge pertaining to growth rates of trees in urban areas, especially indigenous species in developing world countries. Here we report on growth rates of indigenous street and garden trees in Grahamstown, South Africa, using two approaches; tree ring counts on increment cores and mean rates from trees of known planting age. Growth equations for both street and garden trees were derived. There was no significant difference in mean growth rates determined via the two methods. For both methods street trees grew approximately 30% slower than trees in gardens.
- Full Text:
- Date Issued: 2014
The challenges of re-skilling former prison inmates in the 21st century: a case study of Nkonkobe municipality, Eastern Cape - South Africa
- Authors: Ralasi, Nolusindiso
- Date: 2014
- Subjects: Criminals -- Rehabilitation , Prisoners -- Education , Alternatives to imprisonment
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25687 , vital:64432
- Description: The main aim of this study is to investigate challenges of re-skilling former inmates in South Africa in the 21st century. This is a case study of the Nkonkobe Municipality, Eastern Cape - South Africa. The objectives of this research are: to identify the current skills and education programmes offered by the DCS, to establish perceptions of inmates regarding the role of the DCS in skills training and education, to find out whether the current former inmates feel the support of society, to ascertain the offenders’ education levels, professional skills and job experience before and after prison, to identify the status of the offenders’ rights and rehabilitation programmes, to provide recommendations on ways to cement policy loopholes that have a deleterious effect on the government’s drive to create a whole new world for the ex-inmates and their holding communities. A qualitative research design was used to collect data from the participants in order to obtain in-depth information concerning the perceived impact of the life skills programmes on the behaviour and conduct of former inmates who participated in the programme. The findings reveal that the life skills programmes had an impact on the behaviour of former inmates because the life skills that they had gained from the programme mostly helped them desist from committing the offences that they used to commit. The life skills also curbed their anti-social behaviour tendencies. The factors that contributed to the success of the project included the approaches that the facilitators used to run the project, such as, motivating the inmates in everything that they did and the cooperation between the facilitators, the prison and the community. The findings also reveal that the good team work that occurred between the former inmates, support from the community, as well as the support from the Department of Correctional Services contributed to the success of the project. It was also suggested that the project should include all youths in the community; imprisonment should not be a passport to empowerment. The final suggestion was that the project should include all stakeholders in the community. The life skills projects should target unemployed youths in the communities so that they can gain skills that can help them become self-employed. The study also recommends that the life skills programmes should be implemented in all prisons in South Africa to provide inmates with life skills that can help them face day-to-day life challenges. This study culminates in the realisation that no life skills programmes can be successful in any society if they exclude the core social members who are law-abiding citizens. This is key to ensure that these programmes do not polarise the society due to empowerment being erroneously viewed as a preserve of those who did not abide by societal laws. This would set a wrong precedence that this study seeks to forestall. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014
- Authors: Ralasi, Nolusindiso
- Date: 2014
- Subjects: Criminals -- Rehabilitation , Prisoners -- Education , Alternatives to imprisonment
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25687 , vital:64432
- Description: The main aim of this study is to investigate challenges of re-skilling former inmates in South Africa in the 21st century. This is a case study of the Nkonkobe Municipality, Eastern Cape - South Africa. The objectives of this research are: to identify the current skills and education programmes offered by the DCS, to establish perceptions of inmates regarding the role of the DCS in skills training and education, to find out whether the current former inmates feel the support of society, to ascertain the offenders’ education levels, professional skills and job experience before and after prison, to identify the status of the offenders’ rights and rehabilitation programmes, to provide recommendations on ways to cement policy loopholes that have a deleterious effect on the government’s drive to create a whole new world for the ex-inmates and their holding communities. A qualitative research design was used to collect data from the participants in order to obtain in-depth information concerning the perceived impact of the life skills programmes on the behaviour and conduct of former inmates who participated in the programme. The findings reveal that the life skills programmes had an impact on the behaviour of former inmates because the life skills that they had gained from the programme mostly helped them desist from committing the offences that they used to commit. The life skills also curbed their anti-social behaviour tendencies. The factors that contributed to the success of the project included the approaches that the facilitators used to run the project, such as, motivating the inmates in everything that they did and the cooperation between the facilitators, the prison and the community. The findings also reveal that the good team work that occurred between the former inmates, support from the community, as well as the support from the Department of Correctional Services contributed to the success of the project. It was also suggested that the project should include all youths in the community; imprisonment should not be a passport to empowerment. The final suggestion was that the project should include all stakeholders in the community. The life skills projects should target unemployed youths in the communities so that they can gain skills that can help them become self-employed. The study also recommends that the life skills programmes should be implemented in all prisons in South Africa to provide inmates with life skills that can help them face day-to-day life challenges. This study culminates in the realisation that no life skills programmes can be successful in any society if they exclude the core social members who are law-abiding citizens. This is key to ensure that these programmes do not polarise the society due to empowerment being erroneously viewed as a preserve of those who did not abide by societal laws. This would set a wrong precedence that this study seeks to forestall. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014
Thaumatotibia leucotreta and the Navel orange: ovipositional preferences and host susceptibility
- Love, C N, Hill, Martin P, Moore, Sean D
- Authors: Love, C N , Hill, Martin P , Moore, Sean D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423811 , vital:72095 , xlink:href="https://doi.org/10.1111/jen.12126"
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), presents a significant threat to the South African citrus industry. To limit income loss due to direct larval damage or from fruit rejection due to the phytosanitary status of this pest, additional pre-harvest control techniques are required for Navel oranges, which are known to be susceptible to T.leucotreta damage. A number of Navel orange cultivars have been developed, and differences in female T. leucotretaovi positional preference and susceptibility of cultivars to larval penetration are known to exist. Navel orange cultivars were grouped according to time of maturity (early, mid- and late season). Female T.leucotreta were subjected to choice and no-choice tests with these cultivars, measured by oviposition. Host susceptibility was tested by allowing neonate T. leucotreta larvae to penetrate the different Navel cultivars. In the early maturing group, Fischer Navels were least preferred for oviposition and the least susceptible to larval penetration. The mid- and late season maturing groupings showed limited differences in oviposition preference, although host susceptibility did appear to be an important factor in assessing the vulnerability of fruit to T. leucotreta. Despite being widely planted in South Africa, the mid-season Palmer Navels were highly susceptible to larval penetration, while for the late season cultivars, Cambria and Glen Ora Late were the least susceptible to T. leucotreta. As a result of these laboratory trials, it is recommended that farmers increase cultivation of Fischer Navels as the principal early season cultivar, avoid Palmer Navels in favour of other mid-season maturing cultivars and give preference to the late maturing Cambria and Glen Ora Late cultivars, to limit T. Leucotreta damage.
- Full Text:
- Date Issued: 2014
- Authors: Love, C N , Hill, Martin P , Moore, Sean D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423811 , vital:72095 , xlink:href="https://doi.org/10.1111/jen.12126"
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), presents a significant threat to the South African citrus industry. To limit income loss due to direct larval damage or from fruit rejection due to the phytosanitary status of this pest, additional pre-harvest control techniques are required for Navel oranges, which are known to be susceptible to T.leucotreta damage. A number of Navel orange cultivars have been developed, and differences in female T. leucotretaovi positional preference and susceptibility of cultivars to larval penetration are known to exist. Navel orange cultivars were grouped according to time of maturity (early, mid- and late season). Female T.leucotreta were subjected to choice and no-choice tests with these cultivars, measured by oviposition. Host susceptibility was tested by allowing neonate T. leucotreta larvae to penetrate the different Navel cultivars. In the early maturing group, Fischer Navels were least preferred for oviposition and the least susceptible to larval penetration. The mid- and late season maturing groupings showed limited differences in oviposition preference, although host susceptibility did appear to be an important factor in assessing the vulnerability of fruit to T. leucotreta. Despite being widely planted in South Africa, the mid-season Palmer Navels were highly susceptible to larval penetration, while for the late season cultivars, Cambria and Glen Ora Late were the least susceptible to T. leucotreta. As a result of these laboratory trials, it is recommended that farmers increase cultivation of Fischer Navels as the principal early season cultivar, avoid Palmer Navels in favour of other mid-season maturing cultivars and give preference to the late maturing Cambria and Glen Ora Late cultivars, to limit T. Leucotreta damage.
- Full Text:
- Date Issued: 2014
Synthesis, photophysicochemical properties and TD-DFT calculations of tetrakis (2-benzoyl-4-chlorophenoxy) phthalocyanines
- Yilmaz, Yusuf, Mack, John, Sener, M Kasim, Sönmez, Mehmet, Nyokong, Tebello
- Authors: Yilmaz, Yusuf , Mack, John , Sener, M Kasim , Sönmez, Mehmet , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241538 , vital:50948 , xlink:href="https://doi.org/10.1142/S1088424614500047"
- Description: The synthesis of metal free, magnesium and zinc tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanine derivatives (2–4) is described along with their characterization by elemental analysis, IR, UV-visible absorption, and 1H NMR spectroscopy and mass spectrometry. Trends observed in the fluorescence, triplet state, singlet oxygen and photodegradation quantum yields and the triplet state lifetimes are also analyzed. The compounds exhibit high solubility in a wide range of organic solvents and no evidence of aggregation was observed over a wide concentration range. The Zn(II) complex (4) was found to have a very high singlet oxygen quantum yield (ΦΔ = 0.78) in dimethylsulfoxide (DMSO) and a reasonably large triplet state quantum yield (ΦT = 0.82). The photophysical and photochemical properties clearly demonstrate that these compounds could prove useful in singlet oxygen applications such as photodynamic therapy (PDT). DFT and TD-DFT calculations were used to assess the impact of the positional isomerism of the 2-benzoyl-4-chlorophenoxy substituents on the electronic structures and optical spectroscopy.
- Full Text:
- Date Issued: 2014
- Authors: Yilmaz, Yusuf , Mack, John , Sener, M Kasim , Sönmez, Mehmet , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241538 , vital:50948 , xlink:href="https://doi.org/10.1142/S1088424614500047"
- Description: The synthesis of metal free, magnesium and zinc tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanine derivatives (2–4) is described along with their characterization by elemental analysis, IR, UV-visible absorption, and 1H NMR spectroscopy and mass spectrometry. Trends observed in the fluorescence, triplet state, singlet oxygen and photodegradation quantum yields and the triplet state lifetimes are also analyzed. The compounds exhibit high solubility in a wide range of organic solvents and no evidence of aggregation was observed over a wide concentration range. The Zn(II) complex (4) was found to have a very high singlet oxygen quantum yield (ΦΔ = 0.78) in dimethylsulfoxide (DMSO) and a reasonably large triplet state quantum yield (ΦT = 0.82). The photophysical and photochemical properties clearly demonstrate that these compounds could prove useful in singlet oxygen applications such as photodynamic therapy (PDT). DFT and TD-DFT calculations were used to assess the impact of the positional isomerism of the 2-benzoyl-4-chlorophenoxy substituents on the electronic structures and optical spectroscopy.
- Full Text:
- Date Issued: 2014
Synthesis, characterization and photodynamic therapy properties of an octa-4-tert-butylphenoxy-substituted phosphorus (V) triazatetrabenzcorrole
- Shi, Maohu, Tian, Jiangwei, Mkhize, Colin, Kubheka, Gugu, Zhou, Jinfeng, Mack, John, Nyokong, Tebello, Shen, Zhen
- Authors: Shi, Maohu , Tian, Jiangwei , Mkhize, Colin , Kubheka, Gugu , Zhou, Jinfeng , Mack, John , Nyokong, Tebello , Shen, Zhen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241494 , vital:50944 , xlink:href="https://doi.org/10.1142/S1088424614500436"
- Description: A novel octa-4-tert-butylphenoxy-substituted phosphorus(V) triazatetrabenzcorrole (PVTBC), has been synthesized and characterized by MALDI-TOF MS and NMR, FT-IR and MCD spectroscopy. The fluorescence emission spectrum was used to determine the fluorescence quantum yield and the quantum yield for singlet oxygen generation was calculated by using 1,3-diphenylisobenzofuran as a scavenger. The photocytoxicity against U87MG cells was measured. The results indicated that PVTBC is potentially useful as an NIR region photosensitizer for photodynamic therapy (PDT).
- Full Text:
- Date Issued: 2014
- Authors: Shi, Maohu , Tian, Jiangwei , Mkhize, Colin , Kubheka, Gugu , Zhou, Jinfeng , Mack, John , Nyokong, Tebello , Shen, Zhen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241494 , vital:50944 , xlink:href="https://doi.org/10.1142/S1088424614500436"
- Description: A novel octa-4-tert-butylphenoxy-substituted phosphorus(V) triazatetrabenzcorrole (PVTBC), has been synthesized and characterized by MALDI-TOF MS and NMR, FT-IR and MCD spectroscopy. The fluorescence emission spectrum was used to determine the fluorescence quantum yield and the quantum yield for singlet oxygen generation was calculated by using 1,3-diphenylisobenzofuran as a scavenger. The photocytoxicity against U87MG cells was measured. The results indicated that PVTBC is potentially useful as an NIR region photosensitizer for photodynamic therapy (PDT).
- Full Text:
- Date Issued: 2014