Photophysicochemical behavior and antimicrobial activity of dihydroxosilicon tris (diaquaplatinum) octacarboxyphthalocyanine
- Managa, Muthumuni, Idowu, Mopelola A, Antunes, Edith M, Nyokong, Tebello
- Authors: Managa, Muthumuni , Idowu, Mopelola A , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241527 , vital:50947 , xlink:href="https://doi.org/10.1016/j.saa.2014.01.087"
- Description: Platination of dihydroxosilicon octacarboxyphthalocyanine (OH)2SiOCPc was successfully carried out to give dihydroxosilicon tris(diaquaplatinum)octacarboxyphthalocyanine (OH)2SiOCPc(Pt)3 conjugate. Slight blue shifting of the absorption spectrum of (OH)2SiOCPc(Pt)3 was observed on conjugation with platinum. Comparative photophysicochemical behavior and antimicrobial photo-activities of (OH)2SiOCPc(Pt)3 conjugate with (OH)2SiOCPc or Pt nanoparticles revealed that the heavy atom, Pt on the periphery of the phthalocyanine significantly enhanced its singlet oxygen generation with a quantum yield of 0.56 obtained for the (OH)2SiOCPc(Pt)3 conjugate. The (OH)2SiOCPc(Pt)3 conjugate showed highest antimicrobial activity towards Candida albicans and Escherichia coli compared to (OH)2SiOCPc and Pt nanoparticles alone under illumination.
- Full Text:
- Date Issued: 2014
- Authors: Managa, Muthumuni , Idowu, Mopelola A , Antunes, Edith M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241527 , vital:50947 , xlink:href="https://doi.org/10.1016/j.saa.2014.01.087"
- Description: Platination of dihydroxosilicon octacarboxyphthalocyanine (OH)2SiOCPc was successfully carried out to give dihydroxosilicon tris(diaquaplatinum)octacarboxyphthalocyanine (OH)2SiOCPc(Pt)3 conjugate. Slight blue shifting of the absorption spectrum of (OH)2SiOCPc(Pt)3 was observed on conjugation with platinum. Comparative photophysicochemical behavior and antimicrobial photo-activities of (OH)2SiOCPc(Pt)3 conjugate with (OH)2SiOCPc or Pt nanoparticles revealed that the heavy atom, Pt on the periphery of the phthalocyanine significantly enhanced its singlet oxygen generation with a quantum yield of 0.56 obtained for the (OH)2SiOCPc(Pt)3 conjugate. The (OH)2SiOCPc(Pt)3 conjugate showed highest antimicrobial activity towards Candida albicans and Escherichia coli compared to (OH)2SiOCPc and Pt nanoparticles alone under illumination.
- Full Text:
- Date Issued: 2014
Photophysicochemical properties and TD-DFT calculations of a novel terminal alkyne substituted metal free phthalocyanine
- Yilmaz, Yusuf, Mack, John, Sönmez, Mehmet, Nyokong, Tebello
- Authors: Yilmaz, Yusuf , Mack, John , Sönmez, Mehmet , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241562 , vital:50950 , xlink:href="https://doi.org/10.1142/S1088424613501241"
- Description: The synthesis of a novel free base tetrakis(prop-2-ynyloxy)phthalocyanine (2) is described, along with its characterization by IR, UV-visible absorption, and 1H NMR spectroscopy and mass spectrometry. The compound exhibited good solubility in a wide range of organic solvents and no significant aggregation was observed over a wide concentration range. The values for the singlet oxygen (ΦΔ), photodegradation, fluorescence (ΦF) and triplet state quantum yields and the fluorescence and triplet state lifetimes are reported. A relatively high ΦΔ value of 0.46 was obtained in DMSO. The ability to carry out "click" chemistry at the ligand periphery enhances the potential utility of 2 for use in bioconjugates in photodynamic therapy (PDT). A moderately high ΦF value of 0.18 is observed for emission in the therapeutic window in the near-IR region, which suggests that it may also be possible to determine the level of localization of 2 in tumor cells through bioimaging.
- Full Text:
- Date Issued: 2014
- Authors: Yilmaz, Yusuf , Mack, John , Sönmez, Mehmet , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241562 , vital:50950 , xlink:href="https://doi.org/10.1142/S1088424613501241"
- Description: The synthesis of a novel free base tetrakis(prop-2-ynyloxy)phthalocyanine (2) is described, along with its characterization by IR, UV-visible absorption, and 1H NMR spectroscopy and mass spectrometry. The compound exhibited good solubility in a wide range of organic solvents and no significant aggregation was observed over a wide concentration range. The values for the singlet oxygen (ΦΔ), photodegradation, fluorescence (ΦF) and triplet state quantum yields and the fluorescence and triplet state lifetimes are reported. A relatively high ΦΔ value of 0.46 was obtained in DMSO. The ability to carry out "click" chemistry at the ligand periphery enhances the potential utility of 2 for use in bioconjugates in photodynamic therapy (PDT). A moderately high ΦF value of 0.18 is observed for emission in the therapeutic window in the near-IR region, which suggests that it may also be possible to determine the level of localization of 2 in tumor cells through bioimaging.
- Full Text:
- Date Issued: 2014
Polyamide nanofiber membranes functionalized with zinc phthalocyanines
- Goethals, Annelies, Mugadza, Tawanda, Arslanoglu, Yasin, Zugle, Ruphino, Antunes, Edith M, Van Hulle, Stijn W, Nyokong, Tebello, De Clerck, Karen
- Authors: Goethals, Annelies , Mugadza, Tawanda , Arslanoglu, Yasin , Zugle, Ruphino , Antunes, Edith M , Van Hulle, Stijn W , Nyokong, Tebello , De Clerck, Karen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241505 , vital:50945 , xlink:href="https://doi.org/10.1002/app.40486"
- Description: Electrospinning is an efficient method for the production of polyamide nanofiber membranes that are suitable for water filtration. Previous studies have shown that nanofiber membranes have high clean water permeability. The pathogen removal efficiency can be improved by functionalization with (organic) biocides. However, these membranes, like other membranes, are vulnerable to fouling which reduces the filtration efficiency. Therefore the present article investigates the potential of zinc phthalocyanines, which can produce singlet oxygen in the presence of visible light, as a functionalizing agent. The polyamide nanofiber membranes were functionalized with phthalocyanines using both a pre-functionalizing and post-functionalizing method. Only the post-functionalization method shows to result in nanofiber membranes capable of producing singlet oxygen. After 30 min 45% of 1,2-diphenylisobenzofuran (DPBF), used as an oxygen quencher, was removed by reaction with singlet oxygen. This resulted in a removal rate of 0.33 mol DBPF mol−1Zn min−1. During short term leaching tests, phthalocyanines could not be detected.
- Full Text:
- Date Issued: 2014
- Authors: Goethals, Annelies , Mugadza, Tawanda , Arslanoglu, Yasin , Zugle, Ruphino , Antunes, Edith M , Van Hulle, Stijn W , Nyokong, Tebello , De Clerck, Karen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241505 , vital:50945 , xlink:href="https://doi.org/10.1002/app.40486"
- Description: Electrospinning is an efficient method for the production of polyamide nanofiber membranes that are suitable for water filtration. Previous studies have shown that nanofiber membranes have high clean water permeability. The pathogen removal efficiency can be improved by functionalization with (organic) biocides. However, these membranes, like other membranes, are vulnerable to fouling which reduces the filtration efficiency. Therefore the present article investigates the potential of zinc phthalocyanines, which can produce singlet oxygen in the presence of visible light, as a functionalizing agent. The polyamide nanofiber membranes were functionalized with phthalocyanines using both a pre-functionalizing and post-functionalizing method. Only the post-functionalization method shows to result in nanofiber membranes capable of producing singlet oxygen. After 30 min 45% of 1,2-diphenylisobenzofuran (DPBF), used as an oxygen quencher, was removed by reaction with singlet oxygen. This resulted in a removal rate of 0.33 mol DBPF mol−1Zn min−1. During short term leaching tests, phthalocyanines could not be detected.
- Full Text:
- Date Issued: 2014
Positioning non-timber forest products on the development agenda
- Shackleton, Charlie M, Pandey, Ashok K
- Authors: Shackleton, Charlie M , Pandey, Ashok K
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180992 , vital:43679 , xlink:href="https://doi.org/10.1016/j.forpol.2013.07.004"
- Description: Non-timber forests products (NTFPs) provide multiple livelihood benefits to local communities and regional and national economies. And yet this knowledge is rarely drawn upon in debates around and design of poverty alleviation or land use policies, strategies and projects. Unless the accumulating wealth of empirical evidence can be translated into policies and approaches at higher levels, and integrated into poverty alleviation programmes, it will have little impact on local and national poverty profiles. In this paper we propose and briefly discuss eight steps to facilitate integration of NTFPs into the development agenda, for the benefit of local communities. These include: (1) proper inventory of NTFP stocks, (2) research on NTFP ecology and sustainable harvest levels, (3) introduction of extension services for NTFPs, (4) inclusion of NTFPs in land management and trade-off decisions, (5) integration of NTFPs into sectoral policies, (6) ensuring NTFP commercialisation is not at the expense of local livelihood needs, (7) promoting security of access and use, and (8) examination of local contextual drivers of unsustainable use. Each is presented along with examples or proposals towards implementation.
- Full Text:
- Date Issued: 2014
- Authors: Shackleton, Charlie M , Pandey, Ashok K
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180992 , vital:43679 , xlink:href="https://doi.org/10.1016/j.forpol.2013.07.004"
- Description: Non-timber forests products (NTFPs) provide multiple livelihood benefits to local communities and regional and national economies. And yet this knowledge is rarely drawn upon in debates around and design of poverty alleviation or land use policies, strategies and projects. Unless the accumulating wealth of empirical evidence can be translated into policies and approaches at higher levels, and integrated into poverty alleviation programmes, it will have little impact on local and national poverty profiles. In this paper we propose and briefly discuss eight steps to facilitate integration of NTFPs into the development agenda, for the benefit of local communities. These include: (1) proper inventory of NTFP stocks, (2) research on NTFP ecology and sustainable harvest levels, (3) introduction of extension services for NTFPs, (4) inclusion of NTFPs in land management and trade-off decisions, (5) integration of NTFPs into sectoral policies, (6) ensuring NTFP commercialisation is not at the expense of local livelihood needs, (7) promoting security of access and use, and (8) examination of local contextual drivers of unsustainable use. Each is presented along with examples or proposals towards implementation.
- Full Text:
- Date Issued: 2014
Potential Gaps during the Transition from the Embodied through Symbolic to Formal Worlds of Reflective Symmetry:
- Mhlolo, Michael K, Schäfer, Marc
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141117 , vital:37945 , https://doi.org/10.1080/10288457.2014.925269
- Description: Even though reflective symmetry is heavily embedded in the everyday, learners continue to experience challenges when they mathematize concepts from this informal/everyday context. In this article we argue that symmetry exists in nature, it can also be symbolized algebraically and it can be abstracted into the world of axioms and theorems. We problematize this multiple nature of symmetry which on one hand is supportive and on the other acts as a contributory factor to learners' gaps in knowledge. Tall's three worlds of mathematics helped us to show the transition of symmetry from the embodied through symbolic to the formal world and the inherent gaps attributed to the shifts in thinking thereof. We then used this same framework to analyse learners' responses to a reflective symmetry task. The results show that many learner responses could be explained explicitly by the lack of flexibility in the applicability of experiences in the embodied world of reflective symmetry.
- Full Text:
- Date Issued: 2014
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141117 , vital:37945 , https://doi.org/10.1080/10288457.2014.925269
- Description: Even though reflective symmetry is heavily embedded in the everyday, learners continue to experience challenges when they mathematize concepts from this informal/everyday context. In this article we argue that symmetry exists in nature, it can also be symbolized algebraically and it can be abstracted into the world of axioms and theorems. We problematize this multiple nature of symmetry which on one hand is supportive and on the other acts as a contributory factor to learners' gaps in knowledge. Tall's three worlds of mathematics helped us to show the transition of symmetry from the embodied through symbolic to the formal world and the inherent gaps attributed to the shifts in thinking thereof. We then used this same framework to analyse learners' responses to a reflective symmetry task. The results show that many learner responses could be explained explicitly by the lack of flexibility in the applicability of experiences in the embodied world of reflective symmetry.
- Full Text:
- Date Issued: 2014
Prioritisation of potential agents for the biological control of the invasive alien weed, Pereskia aculeata (Cactaceae), in South Africa
- Paterson, Iain D, Vitorino, Marcello D, de Cristo, S C, Martin, Grant D, Hill, Martin P
- Authors: Paterson, Iain D , Vitorino, Marcello D , de Cristo, S C , Martin, Grant D , Hill, Martin P
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76946 , vital:30644 , https://doi.org/10.1080/09583157.2013.864382
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Vitorino, Marcello D , de Cristo, S C , Martin, Grant D , Hill, Martin P
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76946 , vital:30644 , https://doi.org/10.1080/09583157.2013.864382
- Description: Pereskia aculeata Miller (Cactaceae) is an invasive alien species in South Africa that is native in Central and South America. In South Africa, P. aculeata outcompetes native plant species leading to a reduction in biodiversity at infested sites. Herbicidal and mechanical control of the plant is ineffective and unsustainable, so biological control is considered the only potential solution. Climatic matching and genotype matching indicated that the most appropriate regions in which to collect biological control agents were Santa Catarina and Rio de Janeiro provinces in Southern Brazil. Surveys throughout the native distribution resulted in 15 natural enemy species that were associated with the plant. Field host range data, as well as previous host plant records, were used to prioritise which of the species were most likely to be suitably host specific for release in South Africa. The mode of damage was used to determine which species were most likely to be damaging and effective if released. The most promising species prioritised for further study, including host specificity and impact studies, were the stem-wilter Catorhintha schaffneri Brailovsky and Garcia (Coreidae); the stem boring species Acanthodoxus machacalis Martins and Monné (Cerambycidae), Cryptorhynchus sp. (Curculionidae) and Maracayia chlorisalis (Walker) (Crambidae) and the fruit galler Asphondylia sp. (Cecidomyiidae). By prioritising the potential biological control agents that are most likely to be host-specific and damaging, the risk of conducting host specificity testing on unsuitable or ineffective biological control agents is reduced.
- Full Text:
- Date Issued: 2014
Re-thinking engagement: Dialogic strategies of alignment in letters to two South African newspapers
- Smith, Jade, Adendorff, Ralph
- Authors: Smith, Jade , Adendorff, Ralph
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125876 , vital:35828 , https://doi.org/10.1080/10228195.2014.909872
- Description: This article uses an appraisal analysis of 40 letters to the Daily Sun and The Times newspapers in South Africa to illustrate a reconceptualisation of the Engagement system. It discusses dialogism (Bakhtin 1981), which inspired the creation of the Engagement framework by White (2003), who classified attempts to either align or disalign readers with a writer’s stance. Contrary to the options for dialogic Engagement proposed by Martin and White (2005) and White and Don (2012), the data suggests that not all Engagement strategies carry equal power of alignment, as the framework’s systemic layout implies. This prompts a re-thinking of the Engagement categories as occurring along a continuum of their strength.
- Full Text:
- Date Issued: 2014
- Authors: Smith, Jade , Adendorff, Ralph
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125876 , vital:35828 , https://doi.org/10.1080/10228195.2014.909872
- Description: This article uses an appraisal analysis of 40 letters to the Daily Sun and The Times newspapers in South Africa to illustrate a reconceptualisation of the Engagement system. It discusses dialogism (Bakhtin 1981), which inspired the creation of the Engagement framework by White (2003), who classified attempts to either align or disalign readers with a writer’s stance. Contrary to the options for dialogic Engagement proposed by Martin and White (2005) and White and Don (2012), the data suggests that not all Engagement strategies carry equal power of alignment, as the framework’s systemic layout implies. This prompts a re-thinking of the Engagement categories as occurring along a continuum of their strength.
- Full Text:
- Date Issued: 2014
Real-time monitoring of 3T3-L1 preadipocyte differentiation using a commercially available electric cell-substrate impedance sensor system
- Kramer, Adam H, Joos-Vandewalle, Julia, Edkins, Adrienne L, Frost, Carminita L, Prinsloo, Earl
- Authors: Kramer, Adam H , Joos-Vandewalle, Julia , Edkins, Adrienne L , Frost, Carminita L , Prinsloo, Earl
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431171 , vital:72751 , xlink:href="https://doi.org/10.1016/j.bbrc.2013.12.123"
- Description: Real-time analysis offers multiple benefits over traditional end point assays. Here, we present a method of monitoring the optimisation of the growth and differentiation of murine 3T3-L1 preadipocytes to adipocytes using the commercially available ACEA xCELLigence Real-Time Cell Analyser Single Plate (RTCA SP) system. Our findings indicate that the ACEA xCELLigence RTCA SP can reproducibly monitor the primary morphological changes in pre- and post-confluent 3T3-L1 fibroblasts induced to differentiate using insulin, dexamethasone, 3-isobutyl-1-methylxanthine and rosiglitazone; and may be a viable primary method of screening compounds for adipogenic factors.
- Full Text:
- Date Issued: 2014
- Authors: Kramer, Adam H , Joos-Vandewalle, Julia , Edkins, Adrienne L , Frost, Carminita L , Prinsloo, Earl
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431171 , vital:72751 , xlink:href="https://doi.org/10.1016/j.bbrc.2013.12.123"
- Description: Real-time analysis offers multiple benefits over traditional end point assays. Here, we present a method of monitoring the optimisation of the growth and differentiation of murine 3T3-L1 preadipocytes to adipocytes using the commercially available ACEA xCELLigence Real-Time Cell Analyser Single Plate (RTCA SP) system. Our findings indicate that the ACEA xCELLigence RTCA SP can reproducibly monitor the primary morphological changes in pre- and post-confluent 3T3-L1 fibroblasts induced to differentiate using insulin, dexamethasone, 3-isobutyl-1-methylxanthine and rosiglitazone; and may be a viable primary method of screening compounds for adipogenic factors.
- Full Text:
- Date Issued: 2014
Real-time monitoring of 3T3-L1 preadipocyte differentiation using a commercially available electric cell-substrate impedance sensor system:
- Kramer, Adam H, Joos-Vandewalle, Julia, Edkins, Adrienne L, Frost, Carminita L, Prinsloo, Earl
- Authors: Kramer, Adam H , Joos-Vandewalle, Julia , Edkins, Adrienne L , Frost, Carminita L , Prinsloo, Earl
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164830 , vital:41176 , DOI: 10.1016/j.bbrc.2013.12.123
- Description: Real-time analysis offers multiple benefits over traditional end point assays. Here, we present a method of monitoring the optimisation of the growth and differentiation of murine 3T3-L1 preadipocytes to adipocytes using the commercially available ACEA xCELLigence Real-Time Cell Analyser Single Plate (RTCA SP) system. Our findings indicate that the ACEA xCELLigence RTCA SP can reproducibly monitor the primary morphological changes in pre- and post-confluent 3T3-L1 fibroblasts induced to differentiate using insulin, dexamethasone, 3-isobutyl-1-methylxanthine and rosiglitazone; and may be a viable primary method of screening compounds for adipogenic factors.
- Full Text:
- Date Issued: 2014
- Authors: Kramer, Adam H , Joos-Vandewalle, Julia , Edkins, Adrienne L , Frost, Carminita L , Prinsloo, Earl
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164830 , vital:41176 , DOI: 10.1016/j.bbrc.2013.12.123
- Description: Real-time analysis offers multiple benefits over traditional end point assays. Here, we present a method of monitoring the optimisation of the growth and differentiation of murine 3T3-L1 preadipocytes to adipocytes using the commercially available ACEA xCELLigence Real-Time Cell Analyser Single Plate (RTCA SP) system. Our findings indicate that the ACEA xCELLigence RTCA SP can reproducibly monitor the primary morphological changes in pre- and post-confluent 3T3-L1 fibroblasts induced to differentiate using insulin, dexamethasone, 3-isobutyl-1-methylxanthine and rosiglitazone; and may be a viable primary method of screening compounds for adipogenic factors.
- Full Text:
- Date Issued: 2014
Reappraising the concept of biocultural diversity: a perspective from South Africa
- Cocks, Michelle L, Wiersum, K Freerk
- Authors: Cocks, Michelle L , Wiersum, K Freerk
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141176 , vital:37950 , DOI: 10.1007/s10745-014-9681-5
- Description: Biocultural diversity has been conceptualised as the sum of the world’s differences regarding biological diversity at all levels and cultural diversity in all its manifestations, and their interactions. The concept is often framed in the context of conservation as a retention versus loss model by emphasizing the religious and spiritual values of the natural environment and the positive interactions between traditional indigenous people and conservation of natural ecosystems and indigenous species. On the basis of our research amongst the ‘non-traditional’ amaXhosa in South Africa, we argue that this interpretation is too narrow and that the concept needs to be reappraised in order to capture the dynamic, complex and relational nature of bio-cultural diversity relations. We conclude that the concept involves a complex of human values and practices related to the three main dimensions of biodiversity at landscapes, species and genetic levels.
- Full Text:
- Date Issued: 2014
- Authors: Cocks, Michelle L , Wiersum, K Freerk
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141176 , vital:37950 , DOI: 10.1007/s10745-014-9681-5
- Description: Biocultural diversity has been conceptualised as the sum of the world’s differences regarding biological diversity at all levels and cultural diversity in all its manifestations, and their interactions. The concept is often framed in the context of conservation as a retention versus loss model by emphasizing the religious and spiritual values of the natural environment and the positive interactions between traditional indigenous people and conservation of natural ecosystems and indigenous species. On the basis of our research amongst the ‘non-traditional’ amaXhosa in South Africa, we argue that this interpretation is too narrow and that the concept needs to be reappraised in order to capture the dynamic, complex and relational nature of bio-cultural diversity relations. We conclude that the concept involves a complex of human values and practices related to the three main dimensions of biodiversity at landscapes, species and genetic levels.
- Full Text:
- Date Issued: 2014
Reclaiming syndicalism: from Spain to South Africa to Global Labour Today
- Authors: van der Walt, Lucien
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144824 , vital:38382 , DOI: 10.15173/glj.v5i2.1153
- Description: Union politics remain central to the new century. It remains central because of the ongoing importance of unions as mass movements, internationally, and because unions, like other popular movements, are confronted with the very real challenge of articulating an alternative, transformative vision. There is much to be learned from the historic and current tradition of anarcho-and revolutionary syndicalism.
- Full Text:
- Date Issued: 2014
- Authors: van der Walt, Lucien
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144824 , vital:38382 , DOI: 10.15173/glj.v5i2.1153
- Description: Union politics remain central to the new century. It remains central because of the ongoing importance of unions as mass movements, internationally, and because unions, like other popular movements, are confronted with the very real challenge of articulating an alternative, transformative vision. There is much to be learned from the historic and current tradition of anarcho-and revolutionary syndicalism.
- Full Text:
- Date Issued: 2014
Residency patterns and migration dynamics of adult bull sharks (Carcharhinus leucas) on the east coast of southern Africa:
- Daly, Ryan, Smale, Malcolm J, Cowley, Paul D, Froneman, P William
- Authors: Daly, Ryan , Smale, Malcolm J , Cowley, Paul D , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143235 , vital:38213 , doi:10.1371/journal.pone.0109357
- Description: Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195–283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. The majority of sharks (n = 16) exhibited temporally and spatially variable residency patterns interspersed with migration events. Ten individuals undertook coastal migrations that ranged between 433 and 709 km (mean = 533 km) with eight of these sharks returning to the study site.
- Full Text:
- Date Issued: 2014
- Authors: Daly, Ryan , Smale, Malcolm J , Cowley, Paul D , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143235 , vital:38213 , doi:10.1371/journal.pone.0109357
- Description: Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195–283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. The majority of sharks (n = 16) exhibited temporally and spatially variable residency patterns interspersed with migration events. Ten individuals undertook coastal migrations that ranged between 433 and 709 km (mean = 533 km) with eight of these sharks returning to the study site.
- Full Text:
- Date Issued: 2014
Rise and fall of apartheid: photography and the bureaucracy of everyday life
- Authors: Simbao, Ruth K
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147604 , vital:38653 , DOI: 10.1080/02533952.2014.998052
- Description: The exhibition catalogue Rise and Fall of Apartheid is a valuable collection of photographic images that create, according to Enwezor, “a critical visualization and interrogation of […] [apartheid’s] normative symbols, signs and representation” (18). The catalogue focuses on African subjects as “agents of their own emancipation” (18), and contextualises South Africa’s anticipation of the end of apartheid within broader global changes in the late 1980s. Essays by Okwui Enwezor, Michael Godby, Achille Mbembe, Darren Newbury, Colin Richards, Patricia Hayes, Andries Walter Olifant, Rory Bester and Khwezi Gule are included in the catalogue, and are interspersed between photographic images that are grouped in chronological clusters: 1948–1959; 1960–1969; 1970–1979; 1980–1989; and 1990–1995.
- Full Text:
- Date Issued: 2014
- Authors: Simbao, Ruth K
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147604 , vital:38653 , DOI: 10.1080/02533952.2014.998052
- Description: The exhibition catalogue Rise and Fall of Apartheid is a valuable collection of photographic images that create, according to Enwezor, “a critical visualization and interrogation of […] [apartheid’s] normative symbols, signs and representation” (18). The catalogue focuses on African subjects as “agents of their own emancipation” (18), and contextualises South Africa’s anticipation of the end of apartheid within broader global changes in the late 1980s. Essays by Okwui Enwezor, Michael Godby, Achille Mbembe, Darren Newbury, Colin Richards, Patricia Hayes, Andries Walter Olifant, Rory Bester and Khwezi Gule are included in the catalogue, and are interspersed between photographic images that are grouped in chronological clusters: 1948–1959; 1960–1969; 1970–1979; 1980–1989; and 1990–1995.
- Full Text:
- Date Issued: 2014
Selective modulation of plasmodial Hsp70s by small molecules with antimalarial activity
- Cockburn, Ingrid, Boshoff, Aileen, Pesce, Eva-Rachele, Blatch, Gregory L
- Authors: Cockburn, Ingrid , Boshoff, Aileen , Pesce, Eva-Rachele , Blatch, Gregory L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431192 , vital:72752 , xlink:href="https://doi.org/10.1515/hsz-2014-0138"
- Description: Plasmodial heat shock protein 70 (Hsp70) chaperones represent a promising new class of antimalarial drug targets because of the important roles they play in the survival and pathogenesis of the malaria parasite Plasmodium falciparum. This study assessed a set of small molecules (lapachol, bromo-β-lapachona and malonganenones A, B and C) as potential modulators of two biologically important plasmodial Hsp70s, the parasite-resident PfHsp70-1 and the exported PfHsp70-x. Compounds of interest were assessed for modulatory effects on the steady-state basal and heat shock protein 40 (Hsp40)-stimulated ATPase activities of PfHsp70-1, PfHsp70-x and human Hsp70, as well as on the protein aggregation suppression activity of PfHsp70-x. The antimalarial marine alkaloid malonganenone A was of particular interest, as it was found to have limited cytotoxicity to mammalian cell lines and exhibited the desired properties of an effective plasmodial Hsp70 modulator. This compound was found to inhibit plasmodial and not human Hsp70 ATPase activity (Hsp40-stimulated), and hindered the aggregation suppression activity of PfHsp70-x. Furthermore, malonganenone A was shown to disrupt the interaction between PfHsp70-x and Hsp40. This is the first report to show that PfHsp70-x has chaperone activity, is stimulated by Hsp40 and can be specifically modulated by small molecule compounds.
- Full Text:
- Date Issued: 2014
- Authors: Cockburn, Ingrid , Boshoff, Aileen , Pesce, Eva-Rachele , Blatch, Gregory L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431192 , vital:72752 , xlink:href="https://doi.org/10.1515/hsz-2014-0138"
- Description: Plasmodial heat shock protein 70 (Hsp70) chaperones represent a promising new class of antimalarial drug targets because of the important roles they play in the survival and pathogenesis of the malaria parasite Plasmodium falciparum. This study assessed a set of small molecules (lapachol, bromo-β-lapachona and malonganenones A, B and C) as potential modulators of two biologically important plasmodial Hsp70s, the parasite-resident PfHsp70-1 and the exported PfHsp70-x. Compounds of interest were assessed for modulatory effects on the steady-state basal and heat shock protein 40 (Hsp40)-stimulated ATPase activities of PfHsp70-1, PfHsp70-x and human Hsp70, as well as on the protein aggregation suppression activity of PfHsp70-x. The antimalarial marine alkaloid malonganenone A was of particular interest, as it was found to have limited cytotoxicity to mammalian cell lines and exhibited the desired properties of an effective plasmodial Hsp70 modulator. This compound was found to inhibit plasmodial and not human Hsp70 ATPase activity (Hsp40-stimulated), and hindered the aggregation suppression activity of PfHsp70-x. Furthermore, malonganenone A was shown to disrupt the interaction between PfHsp70-x and Hsp40. This is the first report to show that PfHsp70-x has chaperone activity, is stimulated by Hsp40 and can be specifically modulated by small molecule compounds.
- Full Text:
- Date Issued: 2014
Sequence and domain conservation of the coelacanth Hsp40 and Hsp90 chaperones suggests conservation of function
- Tastan Bishop, Özlem, Edkins, Adrienne L, Blatch, Gregory L
- Authors: Tastan Bishop, Özlem , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126932 , vital:35936 , https://doi.10.1002/jez.b.22541
- Description: Molecular chaperones and their associated co‐chaperones play an important role in preserving and regulating the active conformational state of cellular proteins. The chaperone complement of the Indonesian Coelacanth, Latimeria menadoensis, was elucidated using transcriptomic sequences. Heat shock protein 90 (Hsp90) and heat shock protein 40 (Hsp40) chaperones, and associated cochaperones were focused on, and homologous human sequences were used to search the sequence databases. Coelacanth homologs of the cytosolic, mitochondrial and endoplasmic reticulum (ER) homologs of human Hsp90 were identified, as well as all of the major co‐chaperones of the cytosolic isoform. Most of the human Hsp40s were found to have coelacanth homologs, and the data suggested that all of the chaperone machinery for protein folding at the ribosome, protein translocation to cellular compartments such as the ER and protein degradation were conserved. Some interesting similarities and differences were identified when interrogating human, mouse, and zebrafish homologs. For example, DnaJB13 is predicted to be a non‐functional Hsp40 in humans, mouse, and zebrafish due to a corrupted histidine‐proline‐aspartic acid (HPD) motif, while the coelacanth homolog has an intact HPD. These and other comparisons enabled important functional and evolutionary questions to be posed for future experimental studies.
- Full Text:
- Date Issued: 2014
- Authors: Tastan Bishop, Özlem , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126932 , vital:35936 , https://doi.10.1002/jez.b.22541
- Description: Molecular chaperones and their associated co‐chaperones play an important role in preserving and regulating the active conformational state of cellular proteins. The chaperone complement of the Indonesian Coelacanth, Latimeria menadoensis, was elucidated using transcriptomic sequences. Heat shock protein 90 (Hsp90) and heat shock protein 40 (Hsp40) chaperones, and associated cochaperones were focused on, and homologous human sequences were used to search the sequence databases. Coelacanth homologs of the cytosolic, mitochondrial and endoplasmic reticulum (ER) homologs of human Hsp90 were identified, as well as all of the major co‐chaperones of the cytosolic isoform. Most of the human Hsp40s were found to have coelacanth homologs, and the data suggested that all of the chaperone machinery for protein folding at the ribosome, protein translocation to cellular compartments such as the ER and protein degradation were conserved. Some interesting similarities and differences were identified when interrogating human, mouse, and zebrafish homologs. For example, DnaJB13 is predicted to be a non‐functional Hsp40 in humans, mouse, and zebrafish due to a corrupted histidine‐proline‐aspartic acid (HPD) motif, while the coelacanth homolog has an intact HPD. These and other comparisons enabled important functional and evolutionary questions to be posed for future experimental studies.
- Full Text:
- Date Issued: 2014
Shame, divine cannibalism, and the spectacle of subaltern suffering in Ken Barris's What Kind of Child:
- Authors: Marais, Mike
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144028 , vital:38304 , https://hdl.handle.net/10520/EJC171544
- Description: This essay examines the aesthetic and ethical dimensions of Ken Barns's portrayal of the life of a street child in What Kind of Child. Responses to literary representations of subaltem suffering are sharply divided. On the one hand, there is the commonsense view that such representations require one to imagine what the situation of other people may be like, and that, in doing so, one opens oneself to their experience of life. To the extent that representations of suffering inspire one to reflect on one's relations to others, they are salutary. On the other hand, though, such depictions, like poverty tourism, may be accused of providing a spectacle of distant suffering that one vicariously experiences from a position of privilege and then dircards.
- Full Text:
- Date Issued: 2014
- Authors: Marais, Mike
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144028 , vital:38304 , https://hdl.handle.net/10520/EJC171544
- Description: This essay examines the aesthetic and ethical dimensions of Ken Barns's portrayal of the life of a street child in What Kind of Child. Responses to literary representations of subaltem suffering are sharply divided. On the one hand, there is the commonsense view that such representations require one to imagine what the situation of other people may be like, and that, in doing so, one opens oneself to their experience of life. To the extent that representations of suffering inspire one to reflect on one's relations to others, they are salutary. On the other hand, though, such depictions, like poverty tourism, may be accused of providing a spectacle of distant suffering that one vicariously experiences from a position of privilege and then dircards.
- Full Text:
- Date Issued: 2014
Simple, illustrated medicines information improves ARV knowledge and patient self-efficacy in limited literacy South African HIV patients:
- Dowse, Roslind, Barford, Kirsty-Lee, Browne, Sara H
- Authors: Dowse, Roslind , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156698 , vital:40039 , DOI: 10.1080/09540121.2014.931559
- Description: Few studies have investigated antiretroviral (ARV) knowledge and self-efficacy in limited literacy patients. Using a randomized controlled study design, we investigated the influence of a simple pre-tested patient information leaflet (PIL) containing both text and illustrations on HIV- and ARV-related knowledge and on self-efficacy over six months in a limited literacy African population. The recruited patients were randomly allocated to either control (standard care) or intervention group (standard care plus illustrated PIL). HIV and medicines-related knowledge was evaluated with a 22-question test at baseline, one, three, and six months. Self-efficacy was assessed using a modified version of the HIV Treatment Adherence Self-Efficacy Scale.
- Full Text:
- Date Issued: 2014
- Authors: Dowse, Roslind , Barford, Kirsty-Lee , Browne, Sara H
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156698 , vital:40039 , DOI: 10.1080/09540121.2014.931559
- Description: Few studies have investigated antiretroviral (ARV) knowledge and self-efficacy in limited literacy patients. Using a randomized controlled study design, we investigated the influence of a simple pre-tested patient information leaflet (PIL) containing both text and illustrations on HIV- and ARV-related knowledge and on self-efficacy over six months in a limited literacy African population. The recruited patients were randomly allocated to either control (standard care) or intervention group (standard care plus illustrated PIL). HIV and medicines-related knowledge was evaluated with a 22-question test at baseline, one, three, and six months. Self-efficacy was assessed using a modified version of the HIV Treatment Adherence Self-Efficacy Scale.
- Full Text:
- Date Issued: 2014
Smallholder farmers’ access to credit in the Amathole District Municipality, Eastern Cape Province, South Africa
- Baiyegunhi, Lloyd J S, Fraser, Gavin C G
- Authors: Baiyegunhi, Lloyd J S , Fraser, Gavin C G
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69351 , vital:29503 , https://jarts.info/index.php/jarts/article/view/2014121946870/814
- Description: Provision of credit has being identified as an important instrument for improving the welfare of smallholder farmers directly and for enhancing productive capacity through financing investment by the farmers in their human and physical capital. This study investigated the individual and household characteristics that influence credit market access in Amathole District Municipality, Eastern Cape Province, South Africa, using a cross sectional data from smallholder farmers’ household survey. The aim is to provide a better understanding of the households’ level socio-economic characteristics, not only because they influence household’s demand for credit but also due to the fact that potential lenders are most likely to base their assessment of borrowers’ creditworthiness on such characteristics. The results of the logistic regression suggest that credit market access was significantly influenced by variables such as gender, education, households’ income, value of assets, savings, dependency ratio, repayment capacity and social capital. Implications for rural credit delivery are discussed.
- Full Text:
- Date Issued: 2014
- Authors: Baiyegunhi, Lloyd J S , Fraser, Gavin C G
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69351 , vital:29503 , https://jarts.info/index.php/jarts/article/view/2014121946870/814
- Description: Provision of credit has being identified as an important instrument for improving the welfare of smallholder farmers directly and for enhancing productive capacity through financing investment by the farmers in their human and physical capital. This study investigated the individual and household characteristics that influence credit market access in Amathole District Municipality, Eastern Cape Province, South Africa, using a cross sectional data from smallholder farmers’ household survey. The aim is to provide a better understanding of the households’ level socio-economic characteristics, not only because they influence household’s demand for credit but also due to the fact that potential lenders are most likely to base their assessment of borrowers’ creditworthiness on such characteristics. The results of the logistic regression suggest that credit market access was significantly influenced by variables such as gender, education, households’ income, value of assets, savings, dependency ratio, repayment capacity and social capital. Implications for rural credit delivery are discussed.
- Full Text:
- Date Issued: 2014
Some life-history parameters of the non-native amphipod Platorchestia platensis (Talitridae) in a warm temperate South African estuary
- Hodgson, Alan N, Booth, Anthony J, David-Engelbrecht, Viginia, Henninger, Tony O
- Authors: Hodgson, Alan N , Booth, Anthony J , David-Engelbrecht, Viginia , Henninger, Tony O
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126976 , vital:35940 , https://doi.10.1080/0035919X.2014.941961
- Description: Density, population structure, growth, mortality and aspects of reproduction of the non-native amphipod Platorchestia platensis were studied for 20 consecutive months (October 2008 to May 2010) in the supralittoral wrack of the Knysna Estuary, South Africa. Amphipod density varied over the sampling period with the lowest numbers recorded in summer (January and February). Ovigerous females with embryos, and juveniles were found in most months with peaks in recruitment found in both April and October, suggesting that in Knysna this species is a biannual breeder. Average female size was significantly greater in winter, with larger females tending to brood more embryos. The largest adults (13.5 mm total length) were always male although the monthly sex ratio was nearly always female biased. Growth rate estimated from a cohort analysis was about 1 mm per month and monthly survival about 69%. The ability to reproduce all year round may be one reason why this introduced species has become established within this warm temperate estuary.
- Full Text:
- Date Issued: 2014
- Authors: Hodgson, Alan N , Booth, Anthony J , David-Engelbrecht, Viginia , Henninger, Tony O
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126976 , vital:35940 , https://doi.10.1080/0035919X.2014.941961
- Description: Density, population structure, growth, mortality and aspects of reproduction of the non-native amphipod Platorchestia platensis were studied for 20 consecutive months (October 2008 to May 2010) in the supralittoral wrack of the Knysna Estuary, South Africa. Amphipod density varied over the sampling period with the lowest numbers recorded in summer (January and February). Ovigerous females with embryos, and juveniles were found in most months with peaks in recruitment found in both April and October, suggesting that in Knysna this species is a biannual breeder. Average female size was significantly greater in winter, with larger females tending to brood more embryos. The largest adults (13.5 mm total length) were always male although the monthly sex ratio was nearly always female biased. Growth rate estimated from a cohort analysis was about 1 mm per month and monthly survival about 69%. The ability to reproduce all year round may be one reason why this introduced species has become established within this warm temperate estuary.
- Full Text:
- Date Issued: 2014
Sorption of hydrophobic organic compounds on natural sorbents and organoclays from aqueous and non-aqueous solutions: a mini-review
- Moyo, Francis, Tandlich, Roman, Wilhelmi, Brendan S, Balaz, Stefan
- Authors: Moyo, Francis , Tandlich, Roman , Wilhelmi, Brendan S , Balaz, Stefan
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71614 , vital:29925 , https://doi.org/10.3390/ijerph110505020
- Description: Renewed focus on the sorption of hydrophobic organic chemicals (HOCs) onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possible role of both in the prevention of environmental contamination by HOCs. Literature data indicates that certain siloxane surfaces can be hydrophobic. Therefore soils can retain HOCs even at low soil organic levels and the extent will depend on the structure of the pollutant and the type and concentration of clay minerals in the sorbent. Clay minerals are wettable by nonpolar solvents and so sorption of HOCs onto them from aqueous and non-aqueous solutions is possible. This is important for two reasons: firstly, the movement and remediation of soil environments will be a function of the concentration and type of clay minerals in the soil. Secondly, low-cost sorbents such as kaolinite and expandable clays can be added to soils or contaminated environments as temporary retention barriers for HOCs. Inorganic cations sorbed onto the kaolinite have a strong influence on the rate and extent of sorption of hydrophobic organic pollutants onto kaolinite. Structural sorbate classes that can be retained by the kaolinite matrix are limited by hydrogen bonding between hydroxyl groups of the octahedral alumosilicate sheet and the tetrahedral sheet with silicon. Soil organic carbon plays a key role in the sorption of HOCs onto soils, but the extent will be strongly affected by the structure of the organic soil matter and the presence of soot. Structural characterisation of soil organic matter in a particular soil should be conducted during a particular contamination event. Contamination by mining extractants and antibiotics will require renewed focus on the use of the QSAR approaches in the context of the sorption of HOCs onto clay minerals from aqueous and non-aqueous solutions.
- Full Text:
- Date Issued: 2014
- Authors: Moyo, Francis , Tandlich, Roman , Wilhelmi, Brendan S , Balaz, Stefan
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71614 , vital:29925 , https://doi.org/10.3390/ijerph110505020
- Description: Renewed focus on the sorption of hydrophobic organic chemicals (HOCs) onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possible role of both in the prevention of environmental contamination by HOCs. Literature data indicates that certain siloxane surfaces can be hydrophobic. Therefore soils can retain HOCs even at low soil organic levels and the extent will depend on the structure of the pollutant and the type and concentration of clay minerals in the sorbent. Clay minerals are wettable by nonpolar solvents and so sorption of HOCs onto them from aqueous and non-aqueous solutions is possible. This is important for two reasons: firstly, the movement and remediation of soil environments will be a function of the concentration and type of clay minerals in the soil. Secondly, low-cost sorbents such as kaolinite and expandable clays can be added to soils or contaminated environments as temporary retention barriers for HOCs. Inorganic cations sorbed onto the kaolinite have a strong influence on the rate and extent of sorption of hydrophobic organic pollutants onto kaolinite. Structural sorbate classes that can be retained by the kaolinite matrix are limited by hydrogen bonding between hydroxyl groups of the octahedral alumosilicate sheet and the tetrahedral sheet with silicon. Soil organic carbon plays a key role in the sorption of HOCs onto soils, but the extent will be strongly affected by the structure of the organic soil matter and the presence of soot. Structural characterisation of soil organic matter in a particular soil should be conducted during a particular contamination event. Contamination by mining extractants and antibiotics will require renewed focus on the use of the QSAR approaches in the context of the sorption of HOCs onto clay minerals from aqueous and non-aqueous solutions.
- Full Text:
- Date Issued: 2014