Conjugation of azide-functionalised CdSe/ZnS quantum dots with tetrakis (5-hexyn-oxy) Fe (II) phthalocyanine via click chemistry for electrocatalysis
- Nxele, Siphesihle R, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188755 , vital:44782 , xlink:href="https://doi.org/10.1016/j.electacta.2016.01.234"
- Description: In this work, azide-funtionalised CdSe/ZnS QDs are conjugated with tetrakis(5-hexyn-oxy) Fe(II) phthalocyanine for the electrocatalytic detection of paraquat. The conjugate was fully characterised using various techniques to confirm the success of the reaction. They also showed good electrocatalytic ability towards the electroreduction of paraquat with limits of detection (LoD) of 5.9 × 10−9 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188755 , vital:44782 , xlink:href="https://doi.org/10.1016/j.electacta.2016.01.234"
- Description: In this work, azide-funtionalised CdSe/ZnS QDs are conjugated with tetrakis(5-hexyn-oxy) Fe(II) phthalocyanine for the electrocatalytic detection of paraquat. The conjugate was fully characterised using various techniques to confirm the success of the reaction. They also showed good electrocatalytic ability towards the electroreduction of paraquat with limits of detection (LoD) of 5.9 × 10−9 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
Constructions of roles in studio teaching and learning
- Authors: Belluigi, Dina Z
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59792 , vital:27651 , https://doi.org/10.1111/jade.12042
- Description: Various constructions of supervisors and students emerge from education literature on art, design and architecture studio pedagogy. Constructions of the supervisor within the studio and during assessment are considered, with a discussion of the threads which underpin them. This is followed by a discussion of some of the current dominant constructions of the student, and possible effects of these roles and relationships on their engagement with learning. As many of these constructions may be inherited or unconscious, a concern for the agency of those involved to rupture, subvert, rescript or resist such constructions motivates this research, while acknowledging that this may be limited by structural and cultural contexts.
- Full Text: false
- Date Issued: 2016
- Authors: Belluigi, Dina Z
- Date: 2016
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59792 , vital:27651 , https://doi.org/10.1111/jade.12042
- Description: Various constructions of supervisors and students emerge from education literature on art, design and architecture studio pedagogy. Constructions of the supervisor within the studio and during assessment are considered, with a discussion of the threads which underpin them. This is followed by a discussion of some of the current dominant constructions of the student, and possible effects of these roles and relationships on their engagement with learning. As many of these constructions may be inherited or unconscious, a concern for the agency of those involved to rupture, subvert, rescript or resist such constructions motivates this research, while acknowledging that this may be limited by structural and cultural contexts.
- Full Text: false
- Date Issued: 2016
Cyclodextrin grafted calcium carbonate vaterite particles: efficient system for tailored release of hydrophobic anticancer or hormone drugs
- Lakkakula, Jaya R, Kurapati, Rajendra, Tynga, Ivan, Krause, Rui W M, Abrahamse, Heidi, Raichur, Ashok M
- Authors: Lakkakula, Jaya R , Kurapati, Rajendra , Tynga, Ivan , Krause, Rui W M , Abrahamse, Heidi , Raichur, Ashok M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125435 , vital:35783 , https://doi.org/10.1039/C6RA12951J
- Description: Porous CaCO3 microparticles have been used earlier for sustained drug release of hydrophilic drugs but have certain drawbacks for use with hydrophobic drugs. Hence, to overcome these drawbacks, a novel composite of CaCO3 along with cyclodextrin (CD–CaCO3) for the delivery of hydrophobic drugs was developed. Cyclodextrins (CDs), when incorporated within CaCO3, increased the porosity and surface area of microparticles thereby enhancing the encapsulation efficiency of hydrophobic drugs (5-Fluorouracil or Na-L-thyroxine) by forming inclusion complexes with cyclodextrin. Thermogravimetric and FTIR studies confirmed the interaction between the cyclodextrin and CaCO3 microparticles. Raman spectra confirmed the peak of vaterite crystals before and after loading of hydrophobic drugs within the composite. In vitro release studies when performed at pH 4.8 (5-Fu) and pH 1.2 (Na-L-thy) showed release at low pH as CaCO3 is soluble at acidic pH unlike slower release at basic pH. Release kinetics followed a Higuchi kinetic model at pH 4.8 (5-Fu) and pH 1.2 (Na-L-thy) respectively.
- Full Text:
- Date Issued: 2016
- Authors: Lakkakula, Jaya R , Kurapati, Rajendra , Tynga, Ivan , Krause, Rui W M , Abrahamse, Heidi , Raichur, Ashok M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125435 , vital:35783 , https://doi.org/10.1039/C6RA12951J
- Description: Porous CaCO3 microparticles have been used earlier for sustained drug release of hydrophilic drugs but have certain drawbacks for use with hydrophobic drugs. Hence, to overcome these drawbacks, a novel composite of CaCO3 along with cyclodextrin (CD–CaCO3) for the delivery of hydrophobic drugs was developed. Cyclodextrins (CDs), when incorporated within CaCO3, increased the porosity and surface area of microparticles thereby enhancing the encapsulation efficiency of hydrophobic drugs (5-Fluorouracil or Na-L-thyroxine) by forming inclusion complexes with cyclodextrin. Thermogravimetric and FTIR studies confirmed the interaction between the cyclodextrin and CaCO3 microparticles. Raman spectra confirmed the peak of vaterite crystals before and after loading of hydrophobic drugs within the composite. In vitro release studies when performed at pH 4.8 (5-Fu) and pH 1.2 (Na-L-thy) showed release at low pH as CaCO3 is soluble at acidic pH unlike slower release at basic pH. Release kinetics followed a Higuchi kinetic model at pH 4.8 (5-Fu) and pH 1.2 (Na-L-thy) respectively.
- Full Text:
- Date Issued: 2016
Cytotoxic activity of marine sponge extracts from the sub-Antarctic Islands and the Southern Ocean
- Olsen, Elisabeth, De Cerf, Christopher, Dziwornu, Godwin A, Puccinelli, Eleonora, Parker-Nance, Shirley, Ansorge, Isabelle J, Samaai, Toufiek, Dingle, Laura M K, Edkins, Adrienne L, Sunassee, Suthananda N
- Authors: Olsen, Elisabeth , De Cerf, Christopher , Dziwornu, Godwin A , Puccinelli, Eleonora , Parker-Nance, Shirley , Ansorge, Isabelle J , Samaai, Toufiek , Dingle, Laura M K , Edkins, Adrienne L , Sunassee, Suthananda N
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66300 , vital:28931 , https://doi.org/10.17159/sajs.2016/20160202
- Description: publisher version , Over the past 50 years, marine invertebrates, especially sponges, have proven to be a valuable source of new and/or bioactive natural products that have the potential to be further developed as lead compounds for pharmaceutical applications. Although marine benthic invertebrate communities occurring off the coast of South Africa have been explored for their biomedicinal potential, the natural product investigation of marine sponges from the sub-Antarctic Islands in the Southern Ocean for the presence of bioactive secondary metabolites has been relatively unexplored thus far. We report here the results for the biological screening of both aqueous and organic extracts prepared from nine specimens of eight species of marine sponges, collected from around Marion Island and the Prince Edward Islands in the Southern Ocean, for their cytotoxic activity against three cancer cell lines. The results obtained through this multidisciplinary collaborative research effort by exclusively South African institutions has provided an exciting opportunity to discover cytotoxic compounds from sub-Antarctic sponges, whilst contributing to our understanding of the biodiversity and geographic distributions of these cold-water invertebrates. Therefore, we acknowledge here the various contributions of the diverse scientific disciplines that played a pivotal role in providing the necessary platform for the future natural products chemistry investigation of these marine sponges from the sub- Antarctic Islands and the Southern Ocean. Significance: This study will contribute to understanding the biodiversity and geographic distributions of sponges in the Southern Ocean. This multidisciplinary project has enabled the investigation of marine sponges for the presence of cytotoxic compounds. Further investigation will lead to the isolation and identification of cytotoxic compounds present in the active sponge extracts. , University of Cape Town; South African Medical Research Council; National Research Foundation (South Africa); CANSA; Rhodes University; Department of Science and Technology; Department of Environmental Affairs; SANAP
- Full Text:
- Date Issued: 2016
- Authors: Olsen, Elisabeth , De Cerf, Christopher , Dziwornu, Godwin A , Puccinelli, Eleonora , Parker-Nance, Shirley , Ansorge, Isabelle J , Samaai, Toufiek , Dingle, Laura M K , Edkins, Adrienne L , Sunassee, Suthananda N
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66300 , vital:28931 , https://doi.org/10.17159/sajs.2016/20160202
- Description: publisher version , Over the past 50 years, marine invertebrates, especially sponges, have proven to be a valuable source of new and/or bioactive natural products that have the potential to be further developed as lead compounds for pharmaceutical applications. Although marine benthic invertebrate communities occurring off the coast of South Africa have been explored for their biomedicinal potential, the natural product investigation of marine sponges from the sub-Antarctic Islands in the Southern Ocean for the presence of bioactive secondary metabolites has been relatively unexplored thus far. We report here the results for the biological screening of both aqueous and organic extracts prepared from nine specimens of eight species of marine sponges, collected from around Marion Island and the Prince Edward Islands in the Southern Ocean, for their cytotoxic activity against three cancer cell lines. The results obtained through this multidisciplinary collaborative research effort by exclusively South African institutions has provided an exciting opportunity to discover cytotoxic compounds from sub-Antarctic sponges, whilst contributing to our understanding of the biodiversity and geographic distributions of these cold-water invertebrates. Therefore, we acknowledge here the various contributions of the diverse scientific disciplines that played a pivotal role in providing the necessary platform for the future natural products chemistry investigation of these marine sponges from the sub- Antarctic Islands and the Southern Ocean. Significance: This study will contribute to understanding the biodiversity and geographic distributions of sponges in the Southern Ocean. This multidisciplinary project has enabled the investigation of marine sponges for the presence of cytotoxic compounds. Further investigation will lead to the isolation and identification of cytotoxic compounds present in the active sponge extracts. , University of Cape Town; South African Medical Research Council; National Research Foundation (South Africa); CANSA; Rhodes University; Department of Science and Technology; Department of Environmental Affairs; SANAP
- Full Text:
- Date Issued: 2016
Decolonising education: visual arts, cohesion, transformation
- Nsele, Z
- Authors: Nsele, Z
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146456 , vital:38527 , https://savah.org.za/2016/01/18/call-for-papers-savah-conference-2016/#more-174
- Description: Rethinking Art History and Visual Culture in a Contemporary Context. The Rhodes Must Fall” and “Fees Must Fall” campaigns which arose in South Africa in the course of 2015, while focused on transformative agendas in a broad sense, also emphasised how various inheritances from the West have played a fundamental role in shaping universities – not only in terms of their curricula but also their institutional cultures more generally. Occurring in a context where the humanities are under threat and where neoliberal forces may upset what we understand as fundamental to the academic project, these recent calls for critical engagement with institutional histories and practices suggest that reconsideration of disciplinary knowledges and understandings have become increasingly urgent.
- Full Text:
- Date Issued: 2016
- Authors: Nsele, Z
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146456 , vital:38527 , https://savah.org.za/2016/01/18/call-for-papers-savah-conference-2016/#more-174
- Description: Rethinking Art History and Visual Culture in a Contemporary Context. The Rhodes Must Fall” and “Fees Must Fall” campaigns which arose in South Africa in the course of 2015, while focused on transformative agendas in a broad sense, also emphasised how various inheritances from the West have played a fundamental role in shaping universities – not only in terms of their curricula but also their institutional cultures more generally. Occurring in a context where the humanities are under threat and where neoliberal forces may upset what we understand as fundamental to the academic project, these recent calls for critical engagement with institutional histories and practices suggest that reconsideration of disciplinary knowledges and understandings have become increasingly urgent.
- Full Text:
- Date Issued: 2016
Design of a Configurable Embedded Network Tap Flow Generation using NetFlow v9 and IPFIX Formats
- Pennefather, Sean, Irwin, Barry V W
- Authors: Pennefather, Sean , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427756 , vital:72460 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622779_Design_of_a_Configurable_Embedded_Network_Tap_Flow_Generation_using_NetFlow_v9_and_IPFIX_Formats/links/5b9a19f2299bf14ad4d6a591/Design-of-a-Configurable-Embedded-Network-Tap-Flow-Generation-using-NetFlow-v9-and-IPFIX-Formats.pdf
- Description: This paper describes the design of a $200 hardware apparatus capable of passively monitoring network transmission at wire speeds of 100Mbit/s and generating NetFlow v9 or IPFIX compliant network flows for a downstream monitoring infrastructure. Testing of the apparatus hardware confirmed no network disruptions regardless of operational or power state while still being capable of correctly monitoring network traffic when configured. System testing under situations of heavy load confirmed apparatus capability at monitoring network traffic and correct generation of network flows compliant with either NetFlow v9 or IPFIX standards.
- Full Text:
- Date Issued: 2016
- Authors: Pennefather, Sean , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427756 , vital:72460 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622779_Design_of_a_Configurable_Embedded_Network_Tap_Flow_Generation_using_NetFlow_v9_and_IPFIX_Formats/links/5b9a19f2299bf14ad4d6a591/Design-of-a-Configurable-Embedded-Network-Tap-Flow-Generation-using-NetFlow-v9-and-IPFIX-Formats.pdf
- Description: This paper describes the design of a $200 hardware apparatus capable of passively monitoring network transmission at wire speeds of 100Mbit/s and generating NetFlow v9 or IPFIX compliant network flows for a downstream monitoring infrastructure. Testing of the apparatus hardware confirmed no network disruptions regardless of operational or power state while still being capable of correctly monitoring network traffic when configured. System testing under situations of heavy load confirmed apparatus capability at monitoring network traffic and correct generation of network flows compliant with either NetFlow v9 or IPFIX standards.
- Full Text:
- Date Issued: 2016
Detecting derivative malware samples using deobfuscation-assisted similarity analysis
- Wrench, Peter, Irwin, Barry V W
- Authors: Wrench, Peter , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429494 , vital:72617 , 10.23919/SAIEE.2016.8531543
- Description: The abundance of PHP-based Remote Access Trojans (or web shells) found in the wild has led malware researchers to develop systems capable of tracking and analysing these shells. In the past, such shells were ably classified using signature matching, a process that is currently unable to cope with the sheer volume and variety of web-based malware in circulation. Although a large percentage of newly-created webshell software incorporates portions of code derived from seminal shells such as c99 and r57, they are able to disguise this by making extensive use of obfuscation techniques intended to frustrate any attempts to dissect or reverse engineer the code. This paper presents an approach to shell classification and analysis (based on similarity to a body of known malware) in an attempt to create a comprehensive taxonomy of PHP-based web shells. Several different measures of similarity were used in conjunction with clustering algorithms and visualisation techniques in order to achieve this. Furthermore, an auxiliary component capable of syntactically deobfuscating PHP code is described. This was employed to reverse idiomatic obfuscation constructs used by software authors. It was found that this deobfuscation dramatically increased the observed levels of similarity by exposing additional code for analysis.
- Full Text:
- Date Issued: 2016
- Authors: Wrench, Peter , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429494 , vital:72617 , 10.23919/SAIEE.2016.8531543
- Description: The abundance of PHP-based Remote Access Trojans (or web shells) found in the wild has led malware researchers to develop systems capable of tracking and analysing these shells. In the past, such shells were ably classified using signature matching, a process that is currently unable to cope with the sheer volume and variety of web-based malware in circulation. Although a large percentage of newly-created webshell software incorporates portions of code derived from seminal shells such as c99 and r57, they are able to disguise this by making extensive use of obfuscation techniques intended to frustrate any attempts to dissect or reverse engineer the code. This paper presents an approach to shell classification and analysis (based on similarity to a body of known malware) in an attempt to create a comprehensive taxonomy of PHP-based web shells. Several different measures of similarity were used in conjunction with clustering algorithms and visualisation techniques in order to achieve this. Furthermore, an auxiliary component capable of syntactically deobfuscating PHP code is described. This was employed to reverse idiomatic obfuscation constructs used by software authors. It was found that this deobfuscation dramatically increased the observed levels of similarity by exposing additional code for analysis.
- Full Text:
- Date Issued: 2016
Detection of plant growth enhancing features in psychrotolerant yeasts from Patagonia (Argentina)
- Mestre, María C, Fontenla, Sonia, Bruzone, Marie C, Fernández, Natalia V, Dames, Joanna F
- Authors: Mestre, María C , Fontenla, Sonia , Bruzone, Marie C , Fernández, Natalia V , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448581 , vital:74744 , https://doi.org/10.1002/jobm.201500728
- Description: This study explores the biotechnological potential for plant production of twelve psychrotolerant yeasts strains from Northwest‐Patagonia. These strains were isolated from different substrates associated with Nothofagus sp. in native forests and Vaccinium sp. in a commercial plantation. Yeasts characterization was performed using in vitro assays to evaluate the production of auxin‐like compounds and siderophores, ability to solubilize inorganic phosphate and to reduce common plant pathogen growth. Strain YF8.3 identified as Aureobasidium pullullans was the main producer of auxin‐like and siderophores compounds. Phosphate solubilization was a characteristic observed by strains L8.12 and CRUB1775 identified as Holtermaniella takashimae and Candida maritima, respectively. Different yeast strains were able to inhibit the growth of Verticillium dahliae PPRI5569 and Pythium aphanidermatum PPRI 9009, but they all failed to inhibit the growth of Fusarium oxysporum PPRI5457. The present study, suggests that yeasts present in different environments in Northwestern‐Patagonian have physiological in vitro features which may influence plant growth. These results are promising for the developing of biological products based on Patagonian yeasts for plant production in cold‐temperate regions.
- Full Text:
- Date Issued: 2016
- Authors: Mestre, María C , Fontenla, Sonia , Bruzone, Marie C , Fernández, Natalia V , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448581 , vital:74744 , https://doi.org/10.1002/jobm.201500728
- Description: This study explores the biotechnological potential for plant production of twelve psychrotolerant yeasts strains from Northwest‐Patagonia. These strains were isolated from different substrates associated with Nothofagus sp. in native forests and Vaccinium sp. in a commercial plantation. Yeasts characterization was performed using in vitro assays to evaluate the production of auxin‐like compounds and siderophores, ability to solubilize inorganic phosphate and to reduce common plant pathogen growth. Strain YF8.3 identified as Aureobasidium pullullans was the main producer of auxin‐like and siderophores compounds. Phosphate solubilization was a characteristic observed by strains L8.12 and CRUB1775 identified as Holtermaniella takashimae and Candida maritima, respectively. Different yeast strains were able to inhibit the growth of Verticillium dahliae PPRI5569 and Pythium aphanidermatum PPRI 9009, but they all failed to inhibit the growth of Fusarium oxysporum PPRI5457. The present study, suggests that yeasts present in different environments in Northwestern‐Patagonian have physiological in vitro features which may influence plant growth. These results are promising for the developing of biological products based on Patagonian yeasts for plant production in cold‐temperate regions.
- Full Text:
- Date Issued: 2016
Developing a Multi Platform Countermeasure to Ensure a Secure Home
- Frieslaar, Ibraheem, Irwin, Barry V W
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427772 , vital:72461 , https://www.researchgate.net/profile/Ibraheem-Fries-laar/publication/312219190_Developing_a_Multi_Platform_Countermeasure_to_Ensure_a_Secure_Home/links/587747d508ae8fce492fb5e2/Developing-a-Multi-Platform-Countermeasure-to-Ensure-a-Secure-Home.pdf
- Description: This research proposes an investigation into the side channel analysis attacks against the AES algorithm on high powered devices. Currently the research field into this aspect is fairly new and there is room for more information to be discovered. This research proposes using a Raspberry Pi in conjunction with a Software Defined Radio to capture electromagnetic emanations in the low and high frequency domains. Two well-known side channel attacks will be used to recover the secret information based on the electromagnetic emanations. Furthermore, this research proposes investigating into a possible software countermeasure by using the high-powered devices features such as multi-threading.
- Full Text:
- Date Issued: 2016
- Authors: Frieslaar, Ibraheem , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427772 , vital:72461 , https://www.researchgate.net/profile/Ibraheem-Fries-laar/publication/312219190_Developing_a_Multi_Platform_Countermeasure_to_Ensure_a_Secure_Home/links/587747d508ae8fce492fb5e2/Developing-a-Multi-Platform-Countermeasure-to-Ensure-a-Secure-Home.pdf
- Description: This research proposes an investigation into the side channel analysis attacks against the AES algorithm on high powered devices. Currently the research field into this aspect is fairly new and there is room for more information to be discovered. This research proposes using a Raspberry Pi in conjunction with a Software Defined Radio to capture electromagnetic emanations in the low and high frequency domains. Two well-known side channel attacks will be used to recover the secret information based on the electromagnetic emanations. Furthermore, this research proposes investigating into a possible software countermeasure by using the high-powered devices features such as multi-threading.
- Full Text:
- Date Issued: 2016
Developing biosensors in developing countries: South Africa as a case study
- Fogel, Ronen, Limson, Janice L
- Authors: Fogel, Ronen , Limson, Janice L
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431661 , vital:72794 , xlink:href="https://doi.org/10.3390/bios6010005"
- Description: A mini-review of the reported biosensor research occurring in South Africa evidences a strong emphasis on electrochemical sensor research, guided by the opportunities this transduction platform holds for low-cost and robust sensing of numerous targets. Many of the reported publications centre on fundamental research into the signal transduction method, using model biorecognition elements, in line with international trends. Other research in this field is spread across several areas including: the application of nanotechnology; the identification and validation of biomarkers; development and testing of biorecognition agents (antibodies and aptamers) and design of electro-catalysts, most notably metallophthalocyanine. Biosensor targets commonly featured were pesticides and metals. Areas of regional import to sub-Saharan Africa, such as HIV/AIDs and tuberculosis diagnosis, are also apparent in a review of the available literature. Irrespective of the targets, the challenge to the effective deployment of such sensors remains shaped by social and economic realities such that the requirements thereof are for low-cost and universally easy to operate devices for field settings. While it is difficult to disentangle the intertwined roles of national policy, grant funding availability and, certainly, of global trends in shaping areas of emphasis in research, most notable is the strong role that nanotechnology, and to a certain extent biotechnology, plays in research regarding biosensor construction. Stronger emphasis on collaboration between scientists in theoretical modelling, nanomaterials application and or relevant stakeholders in the specific field (e.g., food or health monitoring) and researchers in biosensor design may help evolve focused research efforts towards development and deployment of low-cost biosensors.
- Full Text:
- Date Issued: 2016
- Authors: Fogel, Ronen , Limson, Janice L
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431661 , vital:72794 , xlink:href="https://doi.org/10.3390/bios6010005"
- Description: A mini-review of the reported biosensor research occurring in South Africa evidences a strong emphasis on electrochemical sensor research, guided by the opportunities this transduction platform holds for low-cost and robust sensing of numerous targets. Many of the reported publications centre on fundamental research into the signal transduction method, using model biorecognition elements, in line with international trends. Other research in this field is spread across several areas including: the application of nanotechnology; the identification and validation of biomarkers; development and testing of biorecognition agents (antibodies and aptamers) and design of electro-catalysts, most notably metallophthalocyanine. Biosensor targets commonly featured were pesticides and metals. Areas of regional import to sub-Saharan Africa, such as HIV/AIDs and tuberculosis diagnosis, are also apparent in a review of the available literature. Irrespective of the targets, the challenge to the effective deployment of such sensors remains shaped by social and economic realities such that the requirements thereof are for low-cost and universally easy to operate devices for field settings. While it is difficult to disentangle the intertwined roles of national policy, grant funding availability and, certainly, of global trends in shaping areas of emphasis in research, most notable is the strong role that nanotechnology, and to a certain extent biotechnology, plays in research regarding biosensor construction. Stronger emphasis on collaboration between scientists in theoretical modelling, nanomaterials application and or relevant stakeholders in the specific field (e.g., food or health monitoring) and researchers in biosensor design may help evolve focused research efforts towards development and deployment of low-cost biosensors.
- Full Text:
- Date Issued: 2016
Development and assessment of a USP Apparatus 3 dissolution test method for sustained-release Nevirapine matrix tablets
- Mwila, Chiluba, Khamanga, Sandile M M, Walker, Roderick B
- Authors: Mwila, Chiluba , Khamanga, Sandile M M , Walker, Roderick B
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184779 , vital:44271 , xlink:href="https://doi.org/10.14227/dt230316p22"
- Description: Dissolution testing is a quality control tool used to assess batch-to-batch performance of dosage forms, thereby providing continued assurance of product quality. Analytical methods for the assessment of pharmaceutical product quality must be validated according to regulatory guidelines to ensure that tests are reliable and valid. Agitation rate, mesh pore size, surfactant concentration, and dissolution medium molarity are experimental parameters that may affect nevirapine (NVP) release and were investigated and optimized to ensure that consistent, reliable, and valid results using Apparatus 3 were produced. Agitation rate was investigated to establish an equivalent response to that observed for NVP release using Apparatus 2 at 50 rpm. A reciprocation rate of 5–10 dpm produced dissolution profiles that were similar to those observed using Apparatus 2. An increase in the molarity of the dissolution medium slightly increased the release rate of NVP, and a 50 mM buffer maintained at pH values mimicking gastrointestinal tract (GIT) conditions was selected for all experiments. With the addition of 2% sodium lauryl sulfate (SLS) to the dissolution medium, >80% NVP was released from the tablets over the test period. The NVP release rate increased with an increase in the mesh pore size; however, the extent of release was not affected by this parameter. Dissolution test samples were analyzed using HPLC, and dissolution methods were validated for NVP stability in the dissolution medium, specificity, linearity and range, repeatability, intermediate precision, and accuracy as defined by ICH. The dissolution method used for testing NVP tablets can be regarded as an appropriate tool for the evaluation of sustained-release (SR) NVP formulations and the impact of formulation composition and product quality attributes on drug release.
- Full Text:
- Date Issued: 2016
- Authors: Mwila, Chiluba , Khamanga, Sandile M M , Walker, Roderick B
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184779 , vital:44271 , xlink:href="https://doi.org/10.14227/dt230316p22"
- Description: Dissolution testing is a quality control tool used to assess batch-to-batch performance of dosage forms, thereby providing continued assurance of product quality. Analytical methods for the assessment of pharmaceutical product quality must be validated according to regulatory guidelines to ensure that tests are reliable and valid. Agitation rate, mesh pore size, surfactant concentration, and dissolution medium molarity are experimental parameters that may affect nevirapine (NVP) release and were investigated and optimized to ensure that consistent, reliable, and valid results using Apparatus 3 were produced. Agitation rate was investigated to establish an equivalent response to that observed for NVP release using Apparatus 2 at 50 rpm. A reciprocation rate of 5–10 dpm produced dissolution profiles that were similar to those observed using Apparatus 2. An increase in the molarity of the dissolution medium slightly increased the release rate of NVP, and a 50 mM buffer maintained at pH values mimicking gastrointestinal tract (GIT) conditions was selected for all experiments. With the addition of 2% sodium lauryl sulfate (SLS) to the dissolution medium, >80% NVP was released from the tablets over the test period. The NVP release rate increased with an increase in the mesh pore size; however, the extent of release was not affected by this parameter. Dissolution test samples were analyzed using HPLC, and dissolution methods were validated for NVP stability in the dissolution medium, specificity, linearity and range, repeatability, intermediate precision, and accuracy as defined by ICH. The dissolution method used for testing NVP tablets can be regarded as an appropriate tool for the evaluation of sustained-release (SR) NVP formulations and the impact of formulation composition and product quality attributes on drug release.
- Full Text:
- Date Issued: 2016
Development Discourse and Global History: From Colonialism to the Sustainable Development Goals. A book review
- Authors: Matthews, Sally
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142257 , vital:38063 , DOI: 10.1080/00220388.2016.1153185
- Description: Development Discourse and Global History: From Colonialism to the Sustainable Development Goals. A book review.
- Full Text:
- Date Issued: 2016
- Authors: Matthews, Sally
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142257 , vital:38063 , DOI: 10.1080/00220388.2016.1153185
- Description: Development Discourse and Global History: From Colonialism to the Sustainable Development Goals. A book review.
- Full Text:
- Date Issued: 2016
Development of nanocomposites of phosphorus-nitrogen co-doped graphene oxide nanosheets and nanosized cobalt phthalocyanines for electrocatalysis
- Shumba, Munyaradzai, Nyokong, Tebello
- Authors: Shumba, Munyaradzai , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188574 , vital:44766 , xlink:href="https://doi.org/10.1016/j.electacta.2016.07.079"
- Description: Conjugates of reduced phosphorus-nitrogen co-doped graphene oxide nanosheets (rPNDGONS), reduced phosphorus doped graphene oxide nanosheets (rPDGONS), reduced nitrogen doped graphene oxide nanosheets (rNDGONS), reduced pyrolised graphene oxide nanosheets (rpyGONS) with nanosized cobalt (II) phthalocyanine (CoPcNP) or cobalt tetra amino phenoxy phthalocyanine (CoTAPhPcNP) were characterised and tested for their electrocatalytic behaviour towards the detection of hydrogen peroxide. Cyclic and linear scan voltammetries, and chronoamperometry were used to evaluate the electrocatalytic nature of the designed probes. For hydrogen peroxide detection, CoPcNP-rPNDGONS-GCE oxidation gave sensitivity of 12.00 mA/M, limit of detection of 4.48 nM, a rate constant of 2.66 × 105 M−1 s−1, adsorption equilibrium constant of 3.7 × 102 M−1 and Gibbs free energy −14.84 kJmol−1. The lowest detection limit was obtained for CoTAPhPcNP-rPNDGONS-GCE at 1.21 nM.
- Full Text:
- Date Issued: 2016
- Authors: Shumba, Munyaradzai , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188574 , vital:44766 , xlink:href="https://doi.org/10.1016/j.electacta.2016.07.079"
- Description: Conjugates of reduced phosphorus-nitrogen co-doped graphene oxide nanosheets (rPNDGONS), reduced phosphorus doped graphene oxide nanosheets (rPDGONS), reduced nitrogen doped graphene oxide nanosheets (rNDGONS), reduced pyrolised graphene oxide nanosheets (rpyGONS) with nanosized cobalt (II) phthalocyanine (CoPcNP) or cobalt tetra amino phenoxy phthalocyanine (CoTAPhPcNP) were characterised and tested for their electrocatalytic behaviour towards the detection of hydrogen peroxide. Cyclic and linear scan voltammetries, and chronoamperometry were used to evaluate the electrocatalytic nature of the designed probes. For hydrogen peroxide detection, CoPcNP-rPNDGONS-GCE oxidation gave sensitivity of 12.00 mA/M, limit of detection of 4.48 nM, a rate constant of 2.66 × 105 M−1 s−1, adsorption equilibrium constant of 3.7 × 102 M−1 and Gibbs free energy −14.84 kJmol−1. The lowest detection limit was obtained for CoTAPhPcNP-rPNDGONS-GCE at 1.21 nM.
- Full Text:
- Date Issued: 2016
Developmental and spatial variations in the diet signatures of hyperbenthic shrimp Nauticaris marionis at the Prince Edward Islands based on stable isotope ratios and fatty acid profiles
- Richoux, Nicole B, Allan, Elizabeth L, Froneman, P William
- Authors: Richoux, Nicole B , Allan, Elizabeth L , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67923 , vital:29169 , https://doi.org/10.1016/j.csr.2016.02.0131
- Description: Publisher version , The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.
- Full Text: false
- Date Issued: 2016
- Authors: Richoux, Nicole B , Allan, Elizabeth L , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67923 , vital:29169 , https://doi.org/10.1016/j.csr.2016.02.0131
- Description: Publisher version , The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.
- Full Text: false
- Date Issued: 2016
Diatom-based water quality monitoring in southern Africa: challenges and future prospects
- Dalu, Tatenda, Froneman, P William
- Authors: Dalu, Tatenda , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124297 , vital:35590 , http://dx.doi.org/10.4314/wsa.v42i4.05
- Description: Diatoms are of significant ecological importance in aquatic ecosystems, which stems from their dynamic position at the base of the trophic web as primary producers. Because diatom communities have specific environmental requirements and respond rapidly to changes in environmental conditions they are often employed as a cost-effective method to assess anthropogenic impacts and health statuses of aquatic ecosystems, particularly in Europe and North America. The purpose of this review is to summarise the challenges and future prospects associated with biological water quality monitoring using diatoms with special focus on southern Africa. Much work still needs to be carried out on diatom tolerances, ecological preferences and ecophysiology. It is recommended that past research pertaining to African diatom taxonomy should be made readily accessible to all through electronic media for use as a reference point. Moreover, following the same approach as for macroinvertebrate biomonitoring, African and other developing countries can resort to intermediate diatom taxonomy (i.e. genus), which is easier, less time-consuming and requires less-skilled personnel. While the lack of capacity and baseline information on diatom community composition and ecological requirements represent significant hurdles, diatom biomonitoring potentially holds much promise for understanding the ecological functioning and management of aquatic ecosystems in southern Africa. The application of diatom-based water quality assessment protocols has direct and immediate value for use as an ‘added-value’ assessment tool in addition to the use of macroinvertebrates and fish indices as these can indicate anthropogenically impacted and pristine sites.
- Full Text:
- Date Issued: 2016
- Authors: Dalu, Tatenda , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124297 , vital:35590 , http://dx.doi.org/10.4314/wsa.v42i4.05
- Description: Diatoms are of significant ecological importance in aquatic ecosystems, which stems from their dynamic position at the base of the trophic web as primary producers. Because diatom communities have specific environmental requirements and respond rapidly to changes in environmental conditions they are often employed as a cost-effective method to assess anthropogenic impacts and health statuses of aquatic ecosystems, particularly in Europe and North America. The purpose of this review is to summarise the challenges and future prospects associated with biological water quality monitoring using diatoms with special focus on southern Africa. Much work still needs to be carried out on diatom tolerances, ecological preferences and ecophysiology. It is recommended that past research pertaining to African diatom taxonomy should be made readily accessible to all through electronic media for use as a reference point. Moreover, following the same approach as for macroinvertebrate biomonitoring, African and other developing countries can resort to intermediate diatom taxonomy (i.e. genus), which is easier, less time-consuming and requires less-skilled personnel. While the lack of capacity and baseline information on diatom community composition and ecological requirements represent significant hurdles, diatom biomonitoring potentially holds much promise for understanding the ecological functioning and management of aquatic ecosystems in southern Africa. The application of diatom-based water quality assessment protocols has direct and immediate value for use as an ‘added-value’ assessment tool in addition to the use of macroinvertebrates and fish indices as these can indicate anthropogenically impacted and pristine sites.
- Full Text:
- Date Issued: 2016
Diet of the endemic bivalve Solen cylindraceus inferred from stable isotope analysis in the Kariega Estuary, South Africa
- Nel, Holly A, Froneman, P William
- Authors: Nel, Holly A , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67933 , vital:29170 , https://doi.org/10.1080/13235818.2016.1175917
- Description: Publisher version , Sedentary filter-feeders such as the razor clam (Solen cylindraceus) are believed to indiscriminately exploit a carbon source derived from particulate organic matter (POM). POM demonstrates a high degree of spatial and temporal variability in composition, which may result in intraspecific dietary variation. This study aimed to investigate seasonal ontogenetic shifts in the feeding ecology of S. cylindraceus using dual stable isotopic (δ13C and δ15N) analyses in the oligotrophic temperate permanently open Kariega Estuary, South Africa. Mixing model results demonstrate that the different size classes of S. cylindraceus had a diet comprised mainly of POM. However, size grouping did have a significant effect on carbon and nitrogen signatures. Specifically, during winter, carbon isotopic signatures became more depleted with a decrease in size, while both winter and summer δ15N values became more nitrogen enriched with an increase in size. The observed trend in the ratios can likely be ascribed to the hydrodynamics of the system. Data from this study suggest that there may be some degree of variation among the different size cohorts, although this needs further investigation.
- Full Text: false
- Date Issued: 2016
- Authors: Nel, Holly A , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67933 , vital:29170 , https://doi.org/10.1080/13235818.2016.1175917
- Description: Publisher version , Sedentary filter-feeders such as the razor clam (Solen cylindraceus) are believed to indiscriminately exploit a carbon source derived from particulate organic matter (POM). POM demonstrates a high degree of spatial and temporal variability in composition, which may result in intraspecific dietary variation. This study aimed to investigate seasonal ontogenetic shifts in the feeding ecology of S. cylindraceus using dual stable isotopic (δ13C and δ15N) analyses in the oligotrophic temperate permanently open Kariega Estuary, South Africa. Mixing model results demonstrate that the different size classes of S. cylindraceus had a diet comprised mainly of POM. However, size grouping did have a significant effect on carbon and nitrogen signatures. Specifically, during winter, carbon isotopic signatures became more depleted with a decrease in size, while both winter and summer δ15N values became more nitrogen enriched with an increase in size. The observed trend in the ratios can likely be ascribed to the hydrodynamics of the system. Data from this study suggest that there may be some degree of variation among the different size cohorts, although this needs further investigation.
- Full Text: false
- Date Issued: 2016
Disaster management policy options to address the sanitation challenges in South Africa
- Hoossein, Shafick, Tandlich, Roman, Whittington-Jones, Kevin J, Laubscher, Richard K, Madikizela, Phindile, Zuma, Bongumusa M
- Authors: Hoossein, Shafick , Tandlich, Roman , Whittington-Jones, Kevin J , Laubscher, Richard K , Madikizela, Phindile , Zuma, Bongumusa M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75938 , vital:30485 , https://www.neha.org/node/28591
- Description: The current population of South Africa has been migrating into informal urban settlements that lack adequate sanitation service delivery, caused at least in part by the lack of the necessary skills in the local government sector and the lack of buy in from the community into the provided sanitation facilities. The authors report results of policy research into the relevant disaster management options that could be applied to improve the sanitation service delivery in South Africa. The best policy option was identified as the draft Disaster Management Regulations: Disaster Management. Local government can use these tools through the formation of the volunteer units from the nongovernmental organization sector, the business community, and from among the end users of sanitation facilities. Formation of the volunteer unit should follow the principles of cooperative governance and participatory approach to disaster management. Implementation should be facilitated through the adoption of locally specific municipal by laws.
- Full Text: false
- Date Issued: 2016
- Authors: Hoossein, Shafick , Tandlich, Roman , Whittington-Jones, Kevin J , Laubscher, Richard K , Madikizela, Phindile , Zuma, Bongumusa M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75938 , vital:30485 , https://www.neha.org/node/28591
- Description: The current population of South Africa has been migrating into informal urban settlements that lack adequate sanitation service delivery, caused at least in part by the lack of the necessary skills in the local government sector and the lack of buy in from the community into the provided sanitation facilities. The authors report results of policy research into the relevant disaster management options that could be applied to improve the sanitation service delivery in South Africa. The best policy option was identified as the draft Disaster Management Regulations: Disaster Management. Local government can use these tools through the formation of the volunteer units from the nongovernmental organization sector, the business community, and from among the end users of sanitation facilities. Formation of the volunteer unit should follow the principles of cooperative governance and participatory approach to disaster management. Implementation should be facilitated through the adoption of locally specific municipal by laws.
- Full Text: false
- Date Issued: 2016
Disentangling the identities and distribution patterns of the introduced beachfleas Orchestia gammarellus and Platorchestia platensis (Crustacea: Amphipoda Talitridae) in South Africa
- Diemer, Natalie, Griffiths, Charles L, Hodgson, Alan N
- Authors: Diemer, Natalie , Griffiths, Charles L , Hodgson, Alan N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443163 , vital:74084 , https://doi.org/10.1080/15627020.2016.1268930
- Description: Two introduced beachfleas, Orchestia gammarellus and Platorchestia platensis, have been recorded from South Africa, but have been misidentified by some earlier researchers and, prior to this study, each was also known from just a few, scattered observations, such that their true distributions remained obscure. We illustrate both species to clarify the features that identify and distinguish them and determine their true distributions by re-examining historical samples and by collecting new material from estuaries and lagoons along the west and south coasts of South Africa. Adult males of O. gammarellus have slender antennae and characteristic expanded, flattened, oar-like distal segments on pereopod 7. Adult males of P. platensis have the peduncle of antenna 2 strongly swollen and have bulbous, but not flattened, distal segments on pereopod 7. Both species occur under wrack and other debris along the banks of estuaries and sheltered lagoons. Orchestia gammarellus is found only along the south-west coast, in the Berg River Estuary, Langebaan Lagoon and the Diep River Estuary. Previous records from Knysna were misidentifications of P. platensis. Platorchestia platensis is found at one west coast site, Langebaan Lagoon, but is widely distributed from Cape Point eastwards to at least Algoa Bay. Both species share the same habitats as several other native beachfleas and competitive interactions between native and introduced species merit investigation.
- Full Text:
- Date Issued: 2016
- Authors: Diemer, Natalie , Griffiths, Charles L , Hodgson, Alan N
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443163 , vital:74084 , https://doi.org/10.1080/15627020.2016.1268930
- Description: Two introduced beachfleas, Orchestia gammarellus and Platorchestia platensis, have been recorded from South Africa, but have been misidentified by some earlier researchers and, prior to this study, each was also known from just a few, scattered observations, such that their true distributions remained obscure. We illustrate both species to clarify the features that identify and distinguish them and determine their true distributions by re-examining historical samples and by collecting new material from estuaries and lagoons along the west and south coasts of South Africa. Adult males of O. gammarellus have slender antennae and characteristic expanded, flattened, oar-like distal segments on pereopod 7. Adult males of P. platensis have the peduncle of antenna 2 strongly swollen and have bulbous, but not flattened, distal segments on pereopod 7. Both species occur under wrack and other debris along the banks of estuaries and sheltered lagoons. Orchestia gammarellus is found only along the south-west coast, in the Berg River Estuary, Langebaan Lagoon and the Diep River Estuary. Previous records from Knysna were misidentifications of P. platensis. Platorchestia platensis is found at one west coast site, Langebaan Lagoon, but is widely distributed from Cape Point eastwards to at least Algoa Bay. Both species share the same habitats as several other native beachfleas and competitive interactions between native and introduced species merit investigation.
- Full Text:
- Date Issued: 2016
Distribution and ecological assessment of heavy metals in irrigation channel sediments in a typical rural area of south China
- Gu, Chiming, Liu, Yi, Li, Zhiguo, Mohamed, Ibrahim, Zhang, Ronghua, Brooks, Margot, Chen, Fang
- Authors: Gu, Chiming , Liu, Yi , Li, Zhiguo , Mohamed, Ibrahim , Zhang, Ronghua , Brooks, Margot , Chen, Fang
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66924 , vital:29000 , ISSN 0925-8574 , https://doi.org/10.1016/j.ecoleng.2016.01.054
- Description: Publisher version , Elevated levels of heavy metals in sediments of irrigation channels can pose risks for crops and livestock, as well as for human health. In this study sediment samples were collected from the irrigation channel in a typical rural area of south China, and digested, in order to analyze their contents for the presence of heavy metals Cu, Zn, Pb, Cr, Cd, and Ni, as well as the non-metal As, to assess total concentrations and pollution levels. The pollution load index and potential ecological risk index of these elements were utilized to assess contamination levels and ecotoxicity. Our results showed that the concentrations of the 7 elements were in the order of Zn > Ni > Cr > Cu > As > Pb > Cd. With the exception of Cr and Pb, concentrations of elements were higher than their background in soil, especially for Cd (1.79 mg kg−1), As (99.61 mg kg−1) and Ni (142.62 mg kg−1), which were 18.49, 8.89 and 5.30 times their background concentrations, respectively. The whole sampled zone was characterized by medium pollution and had a very high potential ecological risk. The area of arable land presented a medium pollution risk, while areas near to the path or road showed high risk of pollution. The predominant contributors to elevated ecological risk for the whole zone were Cd and As.
- Full Text: false
- Date Issued: 2016
- Authors: Gu, Chiming , Liu, Yi , Li, Zhiguo , Mohamed, Ibrahim , Zhang, Ronghua , Brooks, Margot , Chen, Fang
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66924 , vital:29000 , ISSN 0925-8574 , https://doi.org/10.1016/j.ecoleng.2016.01.054
- Description: Publisher version , Elevated levels of heavy metals in sediments of irrigation channels can pose risks for crops and livestock, as well as for human health. In this study sediment samples were collected from the irrigation channel in a typical rural area of south China, and digested, in order to analyze their contents for the presence of heavy metals Cu, Zn, Pb, Cr, Cd, and Ni, as well as the non-metal As, to assess total concentrations and pollution levels. The pollution load index and potential ecological risk index of these elements were utilized to assess contamination levels and ecotoxicity. Our results showed that the concentrations of the 7 elements were in the order of Zn > Ni > Cr > Cu > As > Pb > Cd. With the exception of Cr and Pb, concentrations of elements were higher than their background in soil, especially for Cd (1.79 mg kg−1), As (99.61 mg kg−1) and Ni (142.62 mg kg−1), which were 18.49, 8.89 and 5.30 times their background concentrations, respectively. The whole sampled zone was characterized by medium pollution and had a very high potential ecological risk. The area of arable land presented a medium pollution risk, while areas near to the path or road showed high risk of pollution. The predominant contributors to elevated ecological risk for the whole zone were Cd and As.
- Full Text: false
- Date Issued: 2016
Distribution and use of cash income from basket and mat crafting: Implications for rural livelihoods in the Eastern Cape, South Africa
- Adam, Y O, Shackleton, Charlie M
- Authors: Adam, Y O , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180434 , vital:43388 , xlink:href="https://doi.org/10.1080/14728028.2016.1186576"
- Description: The objective of this paper was to investigate the extent to which baskets and mats local trade contributes to rural livelihoods of the crafters’ household and community downstream income. Primary data were collected through structured interviews with 83 crafters from Noqhekwana village in Port St. Johns municipality using snowball sampling in May, 2015. The survey was supplemented by secondary data and direct observations. The findings show that crafting contributed 35% of crafter’s household total income. The received income is spent on expenses in the household and downstream actors depending on the crafter’s priorities. Lack of organization between crafters, access to sufficient raw material, and low prices were identified as major challenges involved in the production and trade of the products.
- Full Text:
- Date Issued: 2016
- Authors: Adam, Y O , Shackleton, Charlie M
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180434 , vital:43388 , xlink:href="https://doi.org/10.1080/14728028.2016.1186576"
- Description: The objective of this paper was to investigate the extent to which baskets and mats local trade contributes to rural livelihoods of the crafters’ household and community downstream income. Primary data were collected through structured interviews with 83 crafters from Noqhekwana village in Port St. Johns municipality using snowball sampling in May, 2015. The survey was supplemented by secondary data and direct observations. The findings show that crafting contributed 35% of crafter’s household total income. The received income is spent on expenses in the household and downstream actors depending on the crafter’s priorities. Lack of organization between crafters, access to sufficient raw material, and low prices were identified as major challenges involved in the production and trade of the products.
- Full Text:
- Date Issued: 2016