Facile synthesis, spectroscopic and electrochemical properties, and theoretical calculations of porphyrin dimers with a bridging amide-bonded xanthene moiety
- Liang, Xu, Xu, Li, Li, Minzhi, Mack, John, Stone, Justin, Nyokong, Tebello, Jiang, Yu, Kobayashi, Nagao, Zhu, Weihua
- Authors: Liang, Xu , Xu, Li , Li, Minzhi , Mack, John , Stone, Justin , Nyokong, Tebello , Jiang, Yu , Kobayashi, Nagao , Zhu, Weihua
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241390 , vital:50935 , xlink:href="https://doi.org/10.1142/S1088424615500492"
- Description: A free base porphyrin dimer bridged by a flexible amide-bonded xanthene moiety and its binuclear zinc(II) complex zinc(II) complex were synthesized and characterized. Structural characterization by MS and 1H NMR spectroscopy confirmed the bridged porphyrin dimer structure. The properties of the dimers were characterized by IR, UV-visible absorption, fluorescence and magnetic circular dichroism (MCD) spectroscopy, and electrochemistry studies. Theoretical calculations were carried out to analyze the electronic structures of porphyrin dimers with a bridging amide-bonded xanthene moiety.
- Full Text:
- Authors: Liang, Xu , Xu, Li , Li, Minzhi , Mack, John , Stone, Justin , Nyokong, Tebello , Jiang, Yu , Kobayashi, Nagao , Zhu, Weihua
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241390 , vital:50935 , xlink:href="https://doi.org/10.1142/S1088424615500492"
- Description: A free base porphyrin dimer bridged by a flexible amide-bonded xanthene moiety and its binuclear zinc(II) complex zinc(II) complex were synthesized and characterized. Structural characterization by MS and 1H NMR spectroscopy confirmed the bridged porphyrin dimer structure. The properties of the dimers were characterized by IR, UV-visible absorption, fluorescence and magnetic circular dichroism (MCD) spectroscopy, and electrochemistry studies. Theoretical calculations were carried out to analyze the electronic structures of porphyrin dimers with a bridging amide-bonded xanthene moiety.
- Full Text:
Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles
- Mthethwa, Thandekile, Nyokong, Tebello
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193598 , vital:45351 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193598 , vital:45351 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles
- Mthethwa, Thandekile, Nyokong, Tebello
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189865 , vital:44941 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189865 , vital:44941 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
- Full Text:
Fluorescence Behaviour of an Aluminium Octacarboxy Phthalocyanine-NaYGdF 4
- Taylor, Jessica, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189503 , vital:44852 , xlink:href="https://doi.org/10.1007/s10895-015-1539-8"
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions).
- Full Text:
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189503 , vital:44852 , xlink:href="https://doi.org/10.1007/s10895-015-1539-8"
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions).
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Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands
- Albert, Simon, Aswani, Shankar, Fisher, Paul L, Albert, Joelle
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
- Full Text:
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
- Full Text:
Genetic and biological characterisation of a novel Plutella xylostella granulovirus, PlxyGV-SA
- Abdulkadir, Fatima, Knox, Caroline M, Marsberg, Tamryn, Hill, Martin P, Moore, Sean D
- Authors: Abdulkadir, Fatima , Knox, Caroline M , Marsberg, Tamryn , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417971 , vital:71498 , xlink:href="https://doi.org/10.1007/s10526-015-9666-3"
- Description: Plutella xylostella granulovirus (PlxyGV) has been isolated from insect populations in many countries and is considered a potential biopesticide for sustainable control of P. xylostella (L.) (Lepidoptera: Plutellidae). Several PlxyGV isolates have been genetically characterised, and the full genome sequence of PlxyGV-Japan is available for comparison with novel isolates. A South African PlxyGV was recently recovered from an overcrowded laboratory P. xylostella colony and identified as a genetically distinct isolate by sequencing of the granulin gene and restriction endonuclease (REN) analysis of genomic DNA. In this report, PlxyGV-SA was further characterised by PCR amplification and sequencing of egt, lef-8 and lef-9 genes, and several amino acid substitutions were observed. The PstI REN profile of PlxyGV-SA was different from that of PlxyGV-Japan in terms of band size and number, thereby confirming its novel genetic identity. Surface dose bioassays showed that PlxyGV-SA is pathogenic to neonate but not late instar larvae at the same and higher virus doses, indicating that a biopesticide should be targeted at early larval stages in the field.
- Full Text:
- Authors: Abdulkadir, Fatima , Knox, Caroline M , Marsberg, Tamryn , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417971 , vital:71498 , xlink:href="https://doi.org/10.1007/s10526-015-9666-3"
- Description: Plutella xylostella granulovirus (PlxyGV) has been isolated from insect populations in many countries and is considered a potential biopesticide for sustainable control of P. xylostella (L.) (Lepidoptera: Plutellidae). Several PlxyGV isolates have been genetically characterised, and the full genome sequence of PlxyGV-Japan is available for comparison with novel isolates. A South African PlxyGV was recently recovered from an overcrowded laboratory P. xylostella colony and identified as a genetically distinct isolate by sequencing of the granulin gene and restriction endonuclease (REN) analysis of genomic DNA. In this report, PlxyGV-SA was further characterised by PCR amplification and sequencing of egt, lef-8 and lef-9 genes, and several amino acid substitutions were observed. The PstI REN profile of PlxyGV-SA was different from that of PlxyGV-Japan in terms of band size and number, thereby confirming its novel genetic identity. Surface dose bioassays showed that PlxyGV-SA is pathogenic to neonate but not late instar larvae at the same and higher virus doses, indicating that a biopesticide should be targeted at early larval stages in the field.
- Full Text:
Global Cicada Sound Collection I: Recordings from South Africa and Malawi by BW Price and MH Villet and harvesting of BioAcoustica data by GBIF
- Baker, Ed, Price, Benjamin W, Rycroft, Simon, Villet, Martin H
- Authors: Baker, Ed , Price, Benjamin W , Rycroft, Simon , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441420 , vital:73886 , https://bdj.pensoft.net/articles.php?id=5792
- Description: Sound collections for singing insects provide important repositories that underpin existing research (eg Price et al. 2007 at http://bio. acousti. ca/node/11801; Price et al. 2010) and make bioacoustic collections available for future work, including insect communication (Ordish 1992), systematics (eg David et al. 2003), and automated identification (Bennett et al. 2015). The BioAcoustica platform (Baker et al. 2015) is both a repository and analysis platform for bioacoustic collections: allowing collections to be available in perpetuity, and also facilitating complex analyses using the BioVeL cloud infrastructure (Vicario et al. 2011). The Global Cicada Sound Collection is a project to make recordings of the world's cicadas (Hemiptera: Cicadidae) available using open licences to maximise their potential for study and reuse. This first component of the Global Cicada Sound Collection comprises recordings made between 2006 and 2008 of Cicadidae in South Africa and Malawi.
- Full Text:
- Authors: Baker, Ed , Price, Benjamin W , Rycroft, Simon , Villet, Martin H
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441420 , vital:73886 , https://bdj.pensoft.net/articles.php?id=5792
- Description: Sound collections for singing insects provide important repositories that underpin existing research (eg Price et al. 2007 at http://bio. acousti. ca/node/11801; Price et al. 2010) and make bioacoustic collections available for future work, including insect communication (Ordish 1992), systematics (eg David et al. 2003), and automated identification (Bennett et al. 2015). The BioAcoustica platform (Baker et al. 2015) is both a repository and analysis platform for bioacoustic collections: allowing collections to be available in perpetuity, and also facilitating complex analyses using the BioVeL cloud infrastructure (Vicario et al. 2011). The Global Cicada Sound Collection is a project to make recordings of the world's cicadas (Hemiptera: Cicadidae) available using open licences to maximise their potential for study and reuse. This first component of the Global Cicada Sound Collection comprises recordings made between 2006 and 2008 of Cicadidae in South Africa and Malawi.
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Historical demography of southern African patellid limpets: congruence of population expansions, but not phylogeography
- Mmonwa, Kolobe L, Teske, Peter R, McQuaid, Christopher D, Barker, Nigel P
- Authors: Mmonwa, Kolobe L , Teske, Peter R , McQuaid, Christopher D , Barker, Nigel P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444814 , vital:74300 , https://doi.org/10.2989/1814232X.2015.1009165
- Description: Global climatic oscillations have shaped the contemporary genetic structure of marine taxa in different ways. Previous demographic studies have indicated that various intertidal marine species display genetic signatures of demographic expansion that either pre- or postdate the Last Glacial Maximum. Such expansions and the ability of species to colonise new habitats will influence their genetic structure, but the link between scales of larval dispersal and the strength of phylogeographic structure is not always clear. We analysed a fragment of the mitochondrial COI gene of 11 sympatric species of intertidal southern African patellid limpets to investigate how ancient oceanographic dynamics have shaped and maintained their contemporary spatial genetic variation. Our data show that the patellid limpets investigated display congruent evidence of spatial expansion during the Late Pleistocene or Early Holocene, which corresponds with the establishment of the contemporary southern African shoreline. We argue that closely related and co-distributed southern African intertidal invertebrates responded to ancient climatic oscillations as a cohesive group. In contrast, contemporary oceanographic circulation has shaped the phylogeographic patterns of these limpets in different ways. We show close relationships between phylogeography and biogeography for some species, but not for others, despite the similarities in their life histories and exposure to the same climatic changes.
- Full Text:
- Authors: Mmonwa, Kolobe L , Teske, Peter R , McQuaid, Christopher D , Barker, Nigel P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444814 , vital:74300 , https://doi.org/10.2989/1814232X.2015.1009165
- Description: Global climatic oscillations have shaped the contemporary genetic structure of marine taxa in different ways. Previous demographic studies have indicated that various intertidal marine species display genetic signatures of demographic expansion that either pre- or postdate the Last Glacial Maximum. Such expansions and the ability of species to colonise new habitats will influence their genetic structure, but the link between scales of larval dispersal and the strength of phylogeographic structure is not always clear. We analysed a fragment of the mitochondrial COI gene of 11 sympatric species of intertidal southern African patellid limpets to investigate how ancient oceanographic dynamics have shaped and maintained their contemporary spatial genetic variation. Our data show that the patellid limpets investigated display congruent evidence of spatial expansion during the Late Pleistocene or Early Holocene, which corresponds with the establishment of the contemporary southern African shoreline. We argue that closely related and co-distributed southern African intertidal invertebrates responded to ancient climatic oscillations as a cohesive group. In contrast, contemporary oceanographic circulation has shaped the phylogeographic patterns of these limpets in different ways. We show close relationships between phylogeography and biogeography for some species, but not for others, despite the similarities in their life histories and exposure to the same climatic changes.
- Full Text:
Hit them where it hurts-tackling Facebook's misogyny problem: journalism next
- Authors: Roux, Kayla
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454745 , vital:75372 , https://hdl.handle.net/10520/EJC175783
- Description: Whether you believe in the power of social networking for political par-ticipation or are cynical of the 'clicktivists' and their 'slacktivism', there's no denying it: social media politics have become an inescapable part of our digital lives. From online petitions and NGO fan pages to heated Twitter wars and politically-motivated hacking, the internet has opened up countless new avenues in which people can express their support for causes, lobby powerful interest groups, and register their dissent with a well-orchestrated hashtag or viral campaign. But what if one so-cial network becomes the site of the struggle? What about when our digital lives become the subject of our politics?
- Full Text:
- Authors: Roux, Kayla
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454745 , vital:75372 , https://hdl.handle.net/10520/EJC175783
- Description: Whether you believe in the power of social networking for political par-ticipation or are cynical of the 'clicktivists' and their 'slacktivism', there's no denying it: social media politics have become an inescapable part of our digital lives. From online petitions and NGO fan pages to heated Twitter wars and politically-motivated hacking, the internet has opened up countless new avenues in which people can express their support for causes, lobby powerful interest groups, and register their dissent with a well-orchestrated hashtag or viral campaign. But what if one so-cial network becomes the site of the struggle? What about when our digital lives become the subject of our politics?
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Host searching and oviposition behaviour of Agathis bishopi (Hymenoptera: Braconidae), a larval parasitoid of false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae): a potential proxy indicator for fruit infestation
- Zimba, Kennedy J, Heshula, Lelethu U P, Moore, Sean D, Hill, Martin P
- Authors: Zimba, Kennedy J , Heshula, Lelethu U P , Moore, Sean D , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
- Full Text:
- Authors: Zimba, Kennedy J , Heshula, Lelethu U P , Moore, Sean D , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
- Full Text:
How General-Purpose can a GPU be?
- Authors: Machanick, Philip
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439294 , vital:73563 , https://hdl.handle.net/10520/EJC181693
- Description: The use of graphics processing units (GPUs) in general-purpose computation (GPGPU) is a growing field. GPU instruction sets, while implementing a graphics pipeline, draw from a range of single instruction multiple data stream (SIMD) architectures characteristic of the heyday of supercomputers. Yet only one of these SIMD instruction sets has been of application on a wide enough range of problems to survive the era when the full range of supercomputer design variants was being explored: vector instructions.
- Full Text:
- Authors: Machanick, Philip
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439294 , vital:73563 , https://hdl.handle.net/10520/EJC181693
- Description: The use of graphics processing units (GPUs) in general-purpose computation (GPGPU) is a growing field. GPU instruction sets, while implementing a graphics pipeline, draw from a range of single instruction multiple data stream (SIMD) architectures characteristic of the heyday of supercomputers. Yet only one of these SIMD instruction sets has been of application on a wide enough range of problems to survive the era when the full range of supercomputer design variants was being explored: vector instructions.
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Human myiasis in rural South Africa is under-reported
- Kuria, Simon K, Villet, Martin H, Kingu, H J C, Dhaffala, A
- Authors: Kuria, Simon K , Villet, Martin H , Kingu, H J C , Dhaffala, A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442425 , vital:73983 , https://www.ajol.info/index.php/samj/article/view/114028
- Description: Background. Myiasis is the infestation of live tissue of humans and other vertebrates by larvae of flies. Worldwide, myiasis of humans is seldom reported, although the trend is gradually changing in some countries. Reports of human myiasis in Africa are few. Several cases of myiasis were recently seen at the Mthatha Hospital Complex, Mthatha, Eastern Cape Province, South Africa (SA).
- Full Text:
- Authors: Kuria, Simon K , Villet, Martin H , Kingu, H J C , Dhaffala, A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442425 , vital:73983 , https://www.ajol.info/index.php/samj/article/view/114028
- Description: Background. Myiasis is the infestation of live tissue of humans and other vertebrates by larvae of flies. Worldwide, myiasis of humans is seldom reported, although the trend is gradually changing in some countries. Reports of human myiasis in Africa are few. Several cases of myiasis were recently seen at the Mthatha Hospital Complex, Mthatha, Eastern Cape Province, South Africa (SA).
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Improved triplet state parameters for indium octacarboxy phthalocyanines when conjugated to quantum dots and magnetite nanoparticles
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189337 , vital:44838 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: Fe3O4 magnetic nanoparticles (MNPs) and glutathione (GSH) capped CdSe@ZnS quantum dots (QDs) were separately coordinated to indium octacarboxy phthalocyanine (InPc(COOH)8) to form ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were determined for the conjugates. The triplet quantum yields increased from ΦT = 0.49 for InPc(COOH)8 alone to ΦT = 0.61 and 0.56 for InPc(COOH)8 in the conjugates: ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The lifetimes also became longer for the conjugates compared to Pc alone.
- Full Text:
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189337 , vital:44838 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: Fe3O4 magnetic nanoparticles (MNPs) and glutathione (GSH) capped CdSe@ZnS quantum dots (QDs) were separately coordinated to indium octacarboxy phthalocyanine (InPc(COOH)8) to form ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were determined for the conjugates. The triplet quantum yields increased from ΦT = 0.49 for InPc(COOH)8 alone to ΦT = 0.61 and 0.56 for InPc(COOH)8 in the conjugates: ClInPc(COOH)8–MNPs and ClInPc(COOH)8–GSH–CdSe@ZnS, respectively. The lifetimes also became longer for the conjugates compared to Pc alone.
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Integrating local knowledge and forest surveys to assess Lantana camara impacts on indigenous species recruitment in Mazeppa Bay, South Africa
- Jevon, Tui, Shackleton, Charlie M
- Authors: Jevon, Tui , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180843 , vital:43650 , xlink:href="https://doi.org/10.1007/s10745-015-9748-y"
- Description: Invasive alien species have variable impacts on peoples’ livelihoods, plant communities and species at the local scale. Local people often have deeper insights into and experiences of these impacts than can be measured by scientific surveys. Here we examine the impacts of Lantana camara on the recruitment of indigenous forest species, many of which are used by local people. We integrate findings from conversations with elderly respondents with standard ecological surveys. Both sources of information indicate that the increasing presence of Lantana suppresses the number and species richness of recruits of indigenous forest species, which may retard forest succession. Dense thickets of Lantana also restricted access to non-timber forest products and species of cultural significance. The origin and date of the Lantana introduction in the area was identified by respondents as the 1960s and it escaped into the wild in the early 1970s. These findings can be incorporated into locally based management considerations.
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- Authors: Jevon, Tui , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180843 , vital:43650 , xlink:href="https://doi.org/10.1007/s10745-015-9748-y"
- Description: Invasive alien species have variable impacts on peoples’ livelihoods, plant communities and species at the local scale. Local people often have deeper insights into and experiences of these impacts than can be measured by scientific surveys. Here we examine the impacts of Lantana camara on the recruitment of indigenous forest species, many of which are used by local people. We integrate findings from conversations with elderly respondents with standard ecological surveys. Both sources of information indicate that the increasing presence of Lantana suppresses the number and species richness of recruits of indigenous forest species, which may retard forest succession. Dense thickets of Lantana also restricted access to non-timber forest products and species of cultural significance. The origin and date of the Lantana introduction in the area was identified by respondents as the 1960s and it escaped into the wild in the early 1970s. These findings can be incorporated into locally based management considerations.
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Introduction, establishment and spread of the Southern mouthbrooder Pseudocrenilabrus philander in the Baakens River, Eastern Cape, South Africa
- Muller, Cuen, Weyl, Olaf L F, Strydom, Nadine A
- Authors: Muller, Cuen , Weyl, Olaf L F , Strydom, Nadine A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443879 , vital:74168 , https://doi.org/10.1080/15627020.2015.1058187
- Description: This paper provides evidence for the extralimital establishment and spread of Pseudocrenilabrus philander in the Baakens River, Eastern Cape, South Africa. Since the first occurrence record at a single locality in 1994 this species has now spread throughout the river and the population contains both reproductive adults and juveniles. Gut content analysis demonstrated potential dietary overlap with native fishes and predation on fish larvae. Pseudocrenilabrus philander in the Baakens River therefore satisfies all criteria for an invasive species in this river and was categorised as invasive using a unified framework for biological invasions.
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- Authors: Muller, Cuen , Weyl, Olaf L F , Strydom, Nadine A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443879 , vital:74168 , https://doi.org/10.1080/15627020.2015.1058187
- Description: This paper provides evidence for the extralimital establishment and spread of Pseudocrenilabrus philander in the Baakens River, Eastern Cape, South Africa. Since the first occurrence record at a single locality in 1994 this species has now spread throughout the river and the population contains both reproductive adults and juveniles. Gut content analysis demonstrated potential dietary overlap with native fishes and predation on fish larvae. Pseudocrenilabrus philander in the Baakens River therefore satisfies all criteria for an invasive species in this river and was categorised as invasive using a unified framework for biological invasions.
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Iodine-Doped Cobalt Phthalocyanine Supported on Multiwalled Carbon Nanotubes for Electrocatalysis of Oxygen Reduction Reaction
- Nyoni, Stephen, Mashazi, Philani N, Nyokong, Tebello
- Authors: Nyoni, Stephen , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189434 , vital:44846 , xlink:href="https://doi.org/10.1002/elan.201400499"
- Description: 4-(4,6-Diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II) (CoPyPc) was iodine doped, and its electrocatalytic properties explored. Physical characterization techniques such as UV-vis, X-ray photoelectron, electron paramagnetic resonance and infra-red spectroscopy were used. Cyclic voltammetry, electrochemical impedance spectroscopy and rotating disk electrode were used for electrochemical characterization of electrodes modified with the prepared phthalocyanine and its nanocomposites. The electrocatalytic effect of a new iodine-doped cobalt phthalocyanine derivative supported on multiwalled carbon nanotubes was then investigated towards oxygen reduction reaction. The electrocatalytic activity of the iodine-doped cobalt phthalocyanine was found to be superior in terms of current over the undoped phthalocyanine nanocomposite.
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- Authors: Nyoni, Stephen , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189434 , vital:44846 , xlink:href="https://doi.org/10.1002/elan.201400499"
- Description: 4-(4,6-Diaminopyrimidin-2-ylthio) phthalocyaninatocobalt(II) (CoPyPc) was iodine doped, and its electrocatalytic properties explored. Physical characterization techniques such as UV-vis, X-ray photoelectron, electron paramagnetic resonance and infra-red spectroscopy were used. Cyclic voltammetry, electrochemical impedance spectroscopy and rotating disk electrode were used for electrochemical characterization of electrodes modified with the prepared phthalocyanine and its nanocomposites. The electrocatalytic effect of a new iodine-doped cobalt phthalocyanine derivative supported on multiwalled carbon nanotubes was then investigated towards oxygen reduction reaction. The electrocatalytic activity of the iodine-doped cobalt phthalocyanine was found to be superior in terms of current over the undoped phthalocyanine nanocomposite.
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Isomerization of the 2-Norbornyl Carbocation
- Authors: Lobb, Kevin A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447992 , vital:74689 , xlink:href="https://doi.org/10.1002/ejoc.201500518"
- Description: In order to elucidate the mechanism for the isomerization of the 2-norbornyl carbocation into its most stable isomer, the 1,3-dimethylcyclopentenyl carbocation, an extensive set of the possible isomers of C7H11+ has been generated. Each one of these may undergo a number of transformations, and location of these transition states provides a searchable graph, from which pathways may be identified. This reveals that the preferred route for isomerization of the 2-norbornyl carbocation is not by ring opening of the non-classical center as has been reported in the literature (with an activation energy of 33.2 kcal/mol), but is initiated by cleavage of the C3–C4 bond (23.5 kcal/mol). Further, no single mechanism is sufficient to describe the full sequence of isomerizations of the 2-norbornyl carbocation to its most stable isomer, the 1,3-dimethylcylcopentenyl carbocation, but rather a collection (> 109) of pathways.
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- Authors: Lobb, Kevin A
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447992 , vital:74689 , xlink:href="https://doi.org/10.1002/ejoc.201500518"
- Description: In order to elucidate the mechanism for the isomerization of the 2-norbornyl carbocation into its most stable isomer, the 1,3-dimethylcyclopentenyl carbocation, an extensive set of the possible isomers of C7H11+ has been generated. Each one of these may undergo a number of transformations, and location of these transition states provides a searchable graph, from which pathways may be identified. This reveals that the preferred route for isomerization of the 2-norbornyl carbocation is not by ring opening of the non-classical center as has been reported in the literature (with an activation energy of 33.2 kcal/mol), but is initiated by cleavage of the C3–C4 bond (23.5 kcal/mol). Further, no single mechanism is sufficient to describe the full sequence of isomerizations of the 2-norbornyl carbocation to its most stable isomer, the 1,3-dimethylcylcopentenyl carbocation, but rather a collection (> 109) of pathways.
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Local wood demand, land cover change and the state of Albany thicket on an urban commonage in the Eastern Cape, South Africa
- Stickler, M M, Shackleton, Charlie M
- Authors: Stickler, M M , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398343 , vital:69402 , xlink:href="https://doi.org/10.1007/s00267-014-0396-6"
- Description: Understanding the rates and causes of land-use change is crucial in identifying solutions, especially in sensitive landscapes and ecosystems, as well as in places undergoing rapid political, socioeconomic or ecological change. Despite considerable concern at the rate of transformation and degradation of the biodiversity-rich Albany Thicket biome in South Africa, most knowledge is gleaned from private commercial lands and state conservation areas. In comparison, there is limited work in communal areas where land uses include biomass extraction, especially for firewood and construction timber. We used aerial photographs to analyze land use and cover change in the high- and low-use zones of an urban commonage and an adjacent protected area over almost six decades, which included a major political transition. Field sampling was undertaken to characterize the current state of the vegetation and soils of the commonage and protected area and to determine the supply and demand for firewood and construction timber. Between the 1950s and 1980s, there was a clear increase in woody vegetation cover, which was reversed after the political transition in the mid-1990s. However, current woody plant standing stocks and sustainable annual production rates are well above current firewood demand, suggesting other probable causes for the decline in woody plant cover. The fragmentation of woody plant cover is paralleled by increases in grassy areas and bare ground, an increase in soil compaction, and decreases in soil moisture, carbon, and nutrients.
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- Authors: Stickler, M M , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398343 , vital:69402 , xlink:href="https://doi.org/10.1007/s00267-014-0396-6"
- Description: Understanding the rates and causes of land-use change is crucial in identifying solutions, especially in sensitive landscapes and ecosystems, as well as in places undergoing rapid political, socioeconomic or ecological change. Despite considerable concern at the rate of transformation and degradation of the biodiversity-rich Albany Thicket biome in South Africa, most knowledge is gleaned from private commercial lands and state conservation areas. In comparison, there is limited work in communal areas where land uses include biomass extraction, especially for firewood and construction timber. We used aerial photographs to analyze land use and cover change in the high- and low-use zones of an urban commonage and an adjacent protected area over almost six decades, which included a major political transition. Field sampling was undertaken to characterize the current state of the vegetation and soils of the commonage and protected area and to determine the supply and demand for firewood and construction timber. Between the 1950s and 1980s, there was a clear increase in woody vegetation cover, which was reversed after the political transition in the mid-1990s. However, current woody plant standing stocks and sustainable annual production rates are well above current firewood demand, suggesting other probable causes for the decline in woody plant cover. The fragmentation of woody plant cover is paralleled by increases in grassy areas and bare ground, an increase in soil compaction, and decreases in soil moisture, carbon, and nutrients.
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Meso-and axially-modified IrIIItriarylcorroles with tunable electrocatalytic properties
- Zhang, Xifeng, Wang, Yu, Zhu, Weihua, Mack, John, Soy, Rodah C, Nyokong, Tebello, Liang, Xu
- Authors: Zhang, Xifeng , Wang, Yu , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Liang, Xu
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190851 , vital:45034 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: The synthesis of three A2B type Ir(III)triarylcorroles with meso-aryl substituents that provide electron donating (push) and withdrawing (pull) properties and three A3 type IrIIItriphenylcorroles with differing pyridine axial ligands is reported, along with their structural characterization. An analysis of the structure-property relationships in the optical and redox properties has been carried out by comparing their optical spectroscopy and electrochemistry to trends predicted in DFT and TD-DFT calculations. The results demonstrate that A2B type IrIIItriarylcorroles are highly efficient electrocatalyzed oxygen reduction reactions (ORRs) and that their reactivity can be modulated by modulating the electronic structure by changing the nature of the meso-substituent at the B-positions, and even axial pyridine ligands.
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- Authors: Zhang, Xifeng , Wang, Yu , Zhu, Weihua , Mack, John , Soy, Rodah C , Nyokong, Tebello , Liang, Xu
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190851 , vital:45034 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: The synthesis of three A2B type Ir(III)triarylcorroles with meso-aryl substituents that provide electron donating (push) and withdrawing (pull) properties and three A3 type IrIIItriphenylcorroles with differing pyridine axial ligands is reported, along with their structural characterization. An analysis of the structure-property relationships in the optical and redox properties has been carried out by comparing their optical spectroscopy and electrochemistry to trends predicted in DFT and TD-DFT calculations. The results demonstrate that A2B type IrIIItriarylcorroles are highly efficient electrocatalyzed oxygen reduction reactions (ORRs) and that their reactivity can be modulated by modulating the electronic structure by changing the nature of the meso-substituent at the B-positions, and even axial pyridine ligands.
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Mips2C: programming from the machine up
- Authors: Machanick, Philip
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439226 , vital:73557 , https://homes.cs.ru.ac.za/philip/Courses/CS2-arch-C/Cs2MIPS2C.pdf
- Description: WHY THIS BOOK? Some years ago I took part in a panel discussion titled “Programming Early Considered Harmful” at the SIGCSE 2001 conference [Hitchner et al. 2001]. Once of those present was Yale Patt, whom I had met briefly on a sabbatical at University of Michigan, where he was at the time a professor working in computer architecture. His role on the panel was to proselytise his book, Introduction to Computing Systems: From bits and gates to C and beyond [Patt and Patel 2013], which introduced programming from the low level up. I found the idea intriguing particularly as I also was concerned with the problem that students tend to stick with the first thing they learn. If my concern was correct, it should be better to start with the programming model you want them to internalize, rather than start with machine level programming. Nonenetheless, I am always open to new ideas, and when the opportunity presented itself to run a computer organization course followed by a C course, I decided to try the idea for myself.
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- Authors: Machanick, Philip
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439226 , vital:73557 , https://homes.cs.ru.ac.za/philip/Courses/CS2-arch-C/Cs2MIPS2C.pdf
- Description: WHY THIS BOOK? Some years ago I took part in a panel discussion titled “Programming Early Considered Harmful” at the SIGCSE 2001 conference [Hitchner et al. 2001]. Once of those present was Yale Patt, whom I had met briefly on a sabbatical at University of Michigan, where he was at the time a professor working in computer architecture. His role on the panel was to proselytise his book, Introduction to Computing Systems: From bits and gates to C and beyond [Patt and Patel 2013], which introduced programming from the low level up. I found the idea intriguing particularly as I also was concerned with the problem that students tend to stick with the first thing they learn. If my concern was correct, it should be better to start with the programming model you want them to internalize, rather than start with machine level programming. Nonenetheless, I am always open to new ideas, and when the opportunity presented itself to run a computer organization course followed by a C course, I decided to try the idea for myself.
- Full Text: