Physicochemical and antimicrobial photodynamic chemotherapy (against E. coli) by indium phthalocyanines in the presence of silver–iron bimetallic nanoparticles
- Magadla, Aviwe, Oluwole, David O, Managa, Muthumuni, Nyokong, Tebello
- Authors: Magadla, Aviwe , Oluwole, David O , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187091 , vital:44564 , xlink:href="https://doi.org/10.1016/j.poly.2019.01.032"
- Description: In this work, Schiff base indium phthalocyanines: In–Cl tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine (complex 1b) and In–Cl tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine (complex 2b) are synthesized from tetra amino and tetra phenoxy amino phthalocyanines, respectively. These complexes were further quartenised with 1,3-propanesultone to form zwitterionic complexes 1 and 2, respectively. Silver–iron dimers (Ag–Fe3O4) and silver-iron core shell (Ag@Fe3O4) nanoparticles (NPs) were linked to the synthesised complexes. The photophysical and photochemical behaviour of the complexes and their conjugates with NPs were investigated in dimethyl sulfoxide. Complexes 2 and 2b and their conjugates were then used for photodynamic antimicrobial chemotherapy on Escherichia coli. The zwitter ionic photosensitiser 2 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2019
- Authors: Magadla, Aviwe , Oluwole, David O , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187091 , vital:44564 , xlink:href="https://doi.org/10.1016/j.poly.2019.01.032"
- Description: In this work, Schiff base indium phthalocyanines: In–Cl tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine (complex 1b) and In–Cl tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine (complex 2b) are synthesized from tetra amino and tetra phenoxy amino phthalocyanines, respectively. These complexes were further quartenised with 1,3-propanesultone to form zwitterionic complexes 1 and 2, respectively. Silver–iron dimers (Ag–Fe3O4) and silver-iron core shell (Ag@Fe3O4) nanoparticles (NPs) were linked to the synthesised complexes. The photophysical and photochemical behaviour of the complexes and their conjugates with NPs were investigated in dimethyl sulfoxide. Complexes 2 and 2b and their conjugates were then used for photodynamic antimicrobial chemotherapy on Escherichia coli. The zwitter ionic photosensitiser 2 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2019
Physicochemical and photodynamic antimicrobial chemotherapy activity of morpholine-substituted phthalocyanines: Effect of point of substitution and central metal
- Sindelo, Azole, Kobayashi, Nagao, Kimura, Mutsumi, Nyokong, Tebello
- Authors: Sindelo, Azole , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187438 , vital:44652 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.01.025"
- Description: In this study, novel metal-free, zinc and indium 1(4),8(11),15(18),22(25)-tetramorpholine (1a, 2a, 3a respectively) and 2(3), 9(10), 16(17),23(24)-tetramorpholine (1b, 2b, 3b respectively) phthalocyanines were synthesized and complexes 2 and 3 were quaternized. The photophysical and photochemical properties were investigated in dimethylsulfoxide. The non-peripherally substituted phthalocyanines generated higher singlet oxygen than the peripherally substituted phthalocyanines. Photodynamic antimicrobial chemotherapy activities towards inactivation of Escherichia coli, Staphylococcus aureus and Candida albican were evaluated, where all the quaternized Pcs showed total elimination of the micro-organism with log reductions greater than 9. Though the neutral Pcs had log reductions less than 2, for C. albican the percentage reduction was 68.5% for 2b showing the antifungal properties of the morpholine group.
- Full Text:
- Date Issued: 2019
- Authors: Sindelo, Azole , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187438 , vital:44652 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.01.025"
- Description: In this study, novel metal-free, zinc and indium 1(4),8(11),15(18),22(25)-tetramorpholine (1a, 2a, 3a respectively) and 2(3), 9(10), 16(17),23(24)-tetramorpholine (1b, 2b, 3b respectively) phthalocyanines were synthesized and complexes 2 and 3 were quaternized. The photophysical and photochemical properties were investigated in dimethylsulfoxide. The non-peripherally substituted phthalocyanines generated higher singlet oxygen than the peripherally substituted phthalocyanines. Photodynamic antimicrobial chemotherapy activities towards inactivation of Escherichia coli, Staphylococcus aureus and Candida albican were evaluated, where all the quaternized Pcs showed total elimination of the micro-organism with log reductions greater than 9. Though the neutral Pcs had log reductions less than 2, for C. albican the percentage reduction was 68.5% for 2b showing the antifungal properties of the morpholine group.
- Full Text:
- Date Issued: 2019
Phytochemical, anti-inflammatory and anti-trypanosomal properties of Anthocleista vogelii Planch (Loganiaceae) stem bark
- Eze, Fabian I, Siwe-Noundou, Xavier, Osadebe, Patience, Krause, Rui W M
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Osadebe, Patience , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194059 , vital:45419 , xlink:href="https://doi.org/10.1016/j.jep.2019.111851"
- Description: Ethnopharmacological relevance: Anthocleista vogelii Planch (Loganiaceae) is used in African Traditional Medicine for the treatment of pain and inflammatory disorders as well as sleeping sickness. Aim of the study: To determine the in vivo anti-inflammatory and in vitro anti-trypanosomal activities of the extracts of A. vogelii stem bark and identify the phytochemical classes of the fractions responsible for the activities. Materials and methods: The in vivo anti-inflammatory activity of the extracts was evaluated using the egg albumin-induced rat paw oedema model while the in vitro anti-trypanosomal activity was assessed on Trypanosoma brucei brucei. The in vitro cytotoxicity was assessed on HeLa (human cervix adenocarcinoma) cell line. Results: The methanolic extract of A. vogelii stem bark, with 11.2% yield, gave LD50 > 5000 mg/kg. The n-hexane fraction of the extract contains steroids, terpenes and fatty acids and yielded non-cytotoxic terpenoidal column fraction with anti-trypanosomal IC50 of 3.0 μg/mL. The ethylacetate fraction at 100 mg/kg dose significantly (p less than 0.05) provoked 37.8, 62.5 and 69.7% inhibition of oedema induced by egg-albumin at the second, fourth and sixth hours respectively. Conclusion: The study demonstrated that the anti-inflammatory and anti-trypanosomal activities of A. vogelii are probably due to non-cytotoxic terpenoids and validated the traditional use of A. vogelii in the treatment of inflammation and sleeping sickness.
- Full Text:
- Date Issued: 2019
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Osadebe, Patience , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194059 , vital:45419 , xlink:href="https://doi.org/10.1016/j.jep.2019.111851"
- Description: Ethnopharmacological relevance: Anthocleista vogelii Planch (Loganiaceae) is used in African Traditional Medicine for the treatment of pain and inflammatory disorders as well as sleeping sickness. Aim of the study: To determine the in vivo anti-inflammatory and in vitro anti-trypanosomal activities of the extracts of A. vogelii stem bark and identify the phytochemical classes of the fractions responsible for the activities. Materials and methods: The in vivo anti-inflammatory activity of the extracts was evaluated using the egg albumin-induced rat paw oedema model while the in vitro anti-trypanosomal activity was assessed on Trypanosoma brucei brucei. The in vitro cytotoxicity was assessed on HeLa (human cervix adenocarcinoma) cell line. Results: The methanolic extract of A. vogelii stem bark, with 11.2% yield, gave LD50 > 5000 mg/kg. The n-hexane fraction of the extract contains steroids, terpenes and fatty acids and yielded non-cytotoxic terpenoidal column fraction with anti-trypanosomal IC50 of 3.0 μg/mL. The ethylacetate fraction at 100 mg/kg dose significantly (p less than 0.05) provoked 37.8, 62.5 and 69.7% inhibition of oedema induced by egg-albumin at the second, fourth and sixth hours respectively. Conclusion: The study demonstrated that the anti-inflammatory and anti-trypanosomal activities of A. vogelii are probably due to non-cytotoxic terpenoids and validated the traditional use of A. vogelii in the treatment of inflammation and sleeping sickness.
- Full Text:
- Date Issued: 2019
Poverty reduction strategies and non-timber forest products
- Pullanikkatil, Deepa, Shackleton, Charlie M
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433583 , vital:72985 , ISBN 978-3-319-75580-9 , https://link.springer.com/chapter/10.1007/978-3-319-75580-9_1
- Description: The first of the 17 Global Goals that make up the 2030 Agenda for Sustainable Development is to end poverty in all its forms everywhere. Although the numbers of poor people in the world has declined over the last few decades, it is still alarmingly high, being approximately 770 million in 2013 (Fig. 1) (World Bank in Understanding Poverty 2017). Currently the majority of the world’s poor live in rural areas, and their livelihoods are dominated by land-based activities including gathering of Non-Timber Forest Products (NTFPs). There were rela tively few studies offering more socially orientated perspectives and insights on the links between NTFP use, dependency and poverty. The ordinary people using NTFPs, their reasons for doing so and their experiences are given in this book.
- Full Text:
- Date Issued: 2019
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433583 , vital:72985 , ISBN 978-3-319-75580-9 , https://link.springer.com/chapter/10.1007/978-3-319-75580-9_1
- Description: The first of the 17 Global Goals that make up the 2030 Agenda for Sustainable Development is to end poverty in all its forms everywhere. Although the numbers of poor people in the world has declined over the last few decades, it is still alarmingly high, being approximately 770 million in 2013 (Fig. 1) (World Bank in Understanding Poverty 2017). Currently the majority of the world’s poor live in rural areas, and their livelihoods are dominated by land-based activities including gathering of Non-Timber Forest Products (NTFPs). There were rela tively few studies offering more socially orientated perspectives and insights on the links between NTFP use, dependency and poverty. The ordinary people using NTFPs, their reasons for doing so and their experiences are given in this book.
- Full Text:
- Date Issued: 2019
Poverty reduction through non-timber forest products
- Pullanikkatil, Deepa, Shackleton, Charlie M
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/433598 , vital:72986 , ISBN 978-3-319-75580-9 , https://doi.org/10.1007/978-3-319-75580-9
- Description: This book narrates personal stories of people from around the world who have used natural products, in particular Non Timber Forest Products (NTFPs) as a means to come out of poverty. Ending poverty remains a major worldwide challenge and is the number one goal under the UN Sustainable Development Goals. The book fills an important knowledge gap; that of personal stories of NTFP users. This has not been part of past publications on NTFPs which tend to focus on statistics and analysis of numbers, thus, the human faces of NTFP users are missing. Narrative stories provide a wealth of data about people and their experiences rather than aggregated classifications, categories and characteristics of poverty. The objective of this book is to illustrate the poverty alleviation potential of NTFPs through documenting the personal life stories of individuals and households that lifted themselves out of poverty through trade of NTFPs. This book is for all who are interested in poverty alleviation and NTFPs.
- Full Text:
- Date Issued: 2019
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/433598 , vital:72986 , ISBN 978-3-319-75580-9 , https://doi.org/10.1007/978-3-319-75580-9
- Description: This book narrates personal stories of people from around the world who have used natural products, in particular Non Timber Forest Products (NTFPs) as a means to come out of poverty. Ending poverty remains a major worldwide challenge and is the number one goal under the UN Sustainable Development Goals. The book fills an important knowledge gap; that of personal stories of NTFP users. This has not been part of past publications on NTFPs which tend to focus on statistics and analysis of numbers, thus, the human faces of NTFP users are missing. Narrative stories provide a wealth of data about people and their experiences rather than aggregated classifications, categories and characteristics of poverty. The objective of this book is to illustrate the poverty alleviation potential of NTFPs through documenting the personal life stories of individuals and households that lifted themselves out of poverty through trade of NTFPs. This book is for all who are interested in poverty alleviation and NTFPs.
- Full Text:
- Date Issued: 2019
Pregnancy Decision Making: Abortion and Adoption
- Mavuso, Jabulile M-J J, Macleod, Catriona I
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434145 , vital:73034 , ISBN 9781119161899 , https://onlinelibrary.wiley.com/doi/book/10.1002/9781119171492
- Description: Pregnancy decision making encompasses a large range of interactions, including decisions and actions to avoid pregnancy or to become pregnant. This entry addresses the question of decision making regarding the outcome of a pregnancy: abortion or taking the pregnancy to term, with the latter resulting in parenting or adoption placement. Adolescents' pregnancy decision making has been a special area of focus for some decades now, particularly regarding whether adolescents are capable of making termination-of-pregnancy decisions. This entry highlights controversies concerning, first, teenage pregnancy as a social problem; second, risk research that seeks to outline the consequences of various reproductive decisions; third, questions around adolescents' maturity regarding making reproductive decisions; fourth, the reasons provided for various reproductive decisions; and, finally, issues surrounding the autonomy of young pregnant women in their reproductive decisions.
- Full Text:
- Date Issued: 2019
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434145 , vital:73034 , ISBN 9781119161899 , https://onlinelibrary.wiley.com/doi/book/10.1002/9781119171492
- Description: Pregnancy decision making encompasses a large range of interactions, including decisions and actions to avoid pregnancy or to become pregnant. This entry addresses the question of decision making regarding the outcome of a pregnancy: abortion or taking the pregnancy to term, with the latter resulting in parenting or adoption placement. Adolescents' pregnancy decision making has been a special area of focus for some decades now, particularly regarding whether adolescents are capable of making termination-of-pregnancy decisions. This entry highlights controversies concerning, first, teenage pregnancy as a social problem; second, risk research that seeks to outline the consequences of various reproductive decisions; third, questions around adolescents' maturity regarding making reproductive decisions; fourth, the reasons provided for various reproductive decisions; and, finally, issues surrounding the autonomy of young pregnant women in their reproductive decisions.
- Full Text:
- Date Issued: 2019
Preparation of NIR absorbing axial substituted tin (iv) porphyrins and their photocytotoxic properties
- Babu, Balaji, Amuhaya, Edith K, Oluwole, David O, Prinsloo, Earl, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Amuhaya, Edith K , Oluwole, David O , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234592 , vital:50211 , xlink:href="https://doi.org/10.1039/C8MD00373D"
- Description: Sn(IV) porphyrins ([Sn(IV)TTP(3PyO)2] (5) and [Sn(IV)TPP(3PyO)2] (6) [tetrathienylporphyrin (TTP), tetraphenylporphyrin (TPP), and pyridyloxy (PyO)]) were prepared and characterized and their photocytotoxicity upon irradiation with 625 nm light has been studied. The presence of the 3PyO axial ligands was found to limit the aggregation and enhance the solubility of 5 and 6 in DMF/H2O (1 : 1). The photophysical properties and photodynamic therapy (PDT) activity of the meso-2-thienyl and meso-phenyl-substituted Sn(IV) porphyrins are compared. 5 and 6 were found to be photocytotoxic in MCF-7 cancer cells when irradiated with a Thorlabs M625L3 LED at 625 nm but remained nontoxic in the dark. The PDT activity of Sn(IV) meso-tetra-2-thienylporphyrin 5 was found to be significantly enhanced relative to its analogous tetraphenylporphyrin 6. There is a marked red-shift of the Q00 band of 5 into the therapeutic window due to the meso-2-thienyl rings, and 5 has an unusually high singlet oxygen quantum yield value of 0.83 in DMF. The results demonstrate that readily synthesized axially ligated Sn(IV) meso-arylporphyrins are potentially suitable for use as singlet oxygen photosensitizers in biomedical applications and merit further in depth investigation in this context.
- Full Text:
- Date Issued: 2019
- Authors: Babu, Balaji , Amuhaya, Edith K , Oluwole, David O , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234592 , vital:50211 , xlink:href="https://doi.org/10.1039/C8MD00373D"
- Description: Sn(IV) porphyrins ([Sn(IV)TTP(3PyO)2] (5) and [Sn(IV)TPP(3PyO)2] (6) [tetrathienylporphyrin (TTP), tetraphenylporphyrin (TPP), and pyridyloxy (PyO)]) were prepared and characterized and their photocytotoxicity upon irradiation with 625 nm light has been studied. The presence of the 3PyO axial ligands was found to limit the aggregation and enhance the solubility of 5 and 6 in DMF/H2O (1 : 1). The photophysical properties and photodynamic therapy (PDT) activity of the meso-2-thienyl and meso-phenyl-substituted Sn(IV) porphyrins are compared. 5 and 6 were found to be photocytotoxic in MCF-7 cancer cells when irradiated with a Thorlabs M625L3 LED at 625 nm but remained nontoxic in the dark. The PDT activity of Sn(IV) meso-tetra-2-thienylporphyrin 5 was found to be significantly enhanced relative to its analogous tetraphenylporphyrin 6. There is a marked red-shift of the Q00 band of 5 into the therapeutic window due to the meso-2-thienyl rings, and 5 has an unusually high singlet oxygen quantum yield value of 0.83 in DMF. The results demonstrate that readily synthesized axially ligated Sn(IV) meso-arylporphyrins are potentially suitable for use as singlet oxygen photosensitizers in biomedical applications and merit further in depth investigation in this context.
- Full Text:
- Date Issued: 2019
Privately protected areas provide key opportunities for the regional persistence of large- and medium-sized mammals
- Clements, Hayley S, Kerley, Graham I, Cumming, Graeme S, de Vos, Alta, Cook, Carly N
- Authors: Clements, Hayley S , Kerley, Graham I , Cumming, Graeme S , de Vos, Alta , Cook, Carly N
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416383 , vital:71344 , xlink:href="https://doi.org/10.1111/1365-2664.13300"
- Description: Biodiversity conservation relies heavily on protected areas (PAs). However, in locations that are desirable for agriculture, industry, or human habitation (e.g., low -land habitats on fertile soils, coastal zones), land is often privately owned and state-owned PAs tend to be under-represented. Despite the potentially disproportionate contribution that privately protected areas (PPAs) could make to representing biodiversity and supporting its persistence across regional PA estates, this contribution is poorly understood.
- Full Text:
- Date Issued: 2019
- Authors: Clements, Hayley S , Kerley, Graham I , Cumming, Graeme S , de Vos, Alta , Cook, Carly N
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416383 , vital:71344 , xlink:href="https://doi.org/10.1111/1365-2664.13300"
- Description: Biodiversity conservation relies heavily on protected areas (PAs). However, in locations that are desirable for agriculture, industry, or human habitation (e.g., low -land habitats on fertile soils, coastal zones), land is often privately owned and state-owned PAs tend to be under-represented. Despite the potentially disproportionate contribution that privately protected areas (PPAs) could make to representing biodiversity and supporting its persistence across regional PA estates, this contribution is poorly understood.
- Full Text:
- Date Issued: 2019
Probing the potential of social ecosystemic skills approaches for green skills planning: Perspectives from Expanded Public Works Programme studies
- Authors: Lotz-Sisitka, Heila
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/392924 , vital:68812 , ISBN 9780429279362 , https://doi.org/10.4324/9780429279362
- Description: The Expanded Public Works Programme (EPWP) in South Africa is an extensive governmental intervention to provide work opportunities. The EPWP context is a significant site of green skills emergence in South Africa, especially at the elementary occupation level. The training associated with these programmes has, to date, been largely top down, and little nuanced understanding exists on the training and learning pathways potential development for these green skills. There is a paradox between the top down approach to training, and the primarily regional implementation platforms of EPWP job opportunities and their developmental intent. To reconcile this paradox, I draw on social ecosystemic skills research to probe the potential for such a conceptual and theoretical framework for guiding green skills research for the EPWP. I share some methodologies and insights developed in EPWP green skills research projects that offer potential for providing insight into a social ecosystemic model for green skills research in EPWP programmes. Social ecosystemic models in skills research seek to develop skills development approaches that forge stronger connections between working, living and learning, foregrounding regional, place-based models for skills planning that require interfacing with vertical facilitatory mechanisms and horizontal connectivities.
- Full Text:
- Date Issued: 2019
- Authors: Lotz-Sisitka, Heila
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/392924 , vital:68812 , ISBN 9780429279362 , https://doi.org/10.4324/9780429279362
- Description: The Expanded Public Works Programme (EPWP) in South Africa is an extensive governmental intervention to provide work opportunities. The EPWP context is a significant site of green skills emergence in South Africa, especially at the elementary occupation level. The training associated with these programmes has, to date, been largely top down, and little nuanced understanding exists on the training and learning pathways potential development for these green skills. There is a paradox between the top down approach to training, and the primarily regional implementation platforms of EPWP job opportunities and their developmental intent. To reconcile this paradox, I draw on social ecosystemic skills research to probe the potential for such a conceptual and theoretical framework for guiding green skills research for the EPWP. I share some methodologies and insights developed in EPWP green skills research projects that offer potential for providing insight into a social ecosystemic model for green skills research in EPWP programmes. Social ecosystemic models in skills research seek to develop skills development approaches that forge stronger connections between working, living and learning, foregrounding regional, place-based models for skills planning that require interfacing with vertical facilitatory mechanisms and horizontal connectivities.
- Full Text:
- Date Issued: 2019
Purification and biochemical characterisation of a putative sodium channel agonist secreted from the South African Knobbly sea anemone Bunodosoma capense
- van Losenoord, Wynand, Krause, Jason, Parker-Nance, Shirley, Krause, Rui W M, Stoychey, Stoyan, Frost, Carminita L
- Authors: van Losenoord, Wynand , Krause, Jason , Parker-Nance, Shirley , Krause, Rui W M , Stoychey, Stoyan , Frost, Carminita L
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194082 , vital:45421 , xlink:href="https://doi.org/10.1016/j.toxicon.2019.06.222"
- Description: Voltage gated ion channels have become a subject of investigation as possible pharmaceutical targets. Research has linked the activity of ion channels directly to anti-inflammatory pathways, energy homeostasis, cancer proliferation and painful diabetic neuropathy. Sea anemones secrete a diverse array of bioactive compounds including potassium and sodium channel toxins. A putative novel sodium channel agonist (molecular mass of 4619.7 Da) with a predicted sequence: CLCNSDGPSV RGNTLSGILW LAGCPSGWHN CKKHKPTIGW CCK was isolated from Bunodosoma capense using a modified stimulation technique to induce the secretion of the neurotoxin rich mucus confirmed by an Artemia nauplii bio-assay. The peptide purification combined size-exclusion and reverse-phase high performance liquid chromatography. A thallium-based ion flux assay confirmed the presence of a sodium channel agonist/inhibitor and purity was determined using a modified tricine SDS-PAGE system. The peptide isolated indicated the presence of multiple disulfide bonds in a tight β-defensin cystine conformation. An IC50 value of 26 nM was determined for total channel inhibition on MCF-7 cells. The unique putative sodium channel agonist initiating with a cystine bond indicates a divergent evolution to those previously isolated from Bunodosoma species.
- Full Text:
- Date Issued: 2019
- Authors: van Losenoord, Wynand , Krause, Jason , Parker-Nance, Shirley , Krause, Rui W M , Stoychey, Stoyan , Frost, Carminita L
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194082 , vital:45421 , xlink:href="https://doi.org/10.1016/j.toxicon.2019.06.222"
- Description: Voltage gated ion channels have become a subject of investigation as possible pharmaceutical targets. Research has linked the activity of ion channels directly to anti-inflammatory pathways, energy homeostasis, cancer proliferation and painful diabetic neuropathy. Sea anemones secrete a diverse array of bioactive compounds including potassium and sodium channel toxins. A putative novel sodium channel agonist (molecular mass of 4619.7 Da) with a predicted sequence: CLCNSDGPSV RGNTLSGILW LAGCPSGWHN CKKHKPTIGW CCK was isolated from Bunodosoma capense using a modified stimulation technique to induce the secretion of the neurotoxin rich mucus confirmed by an Artemia nauplii bio-assay. The peptide purification combined size-exclusion and reverse-phase high performance liquid chromatography. A thallium-based ion flux assay confirmed the presence of a sodium channel agonist/inhibitor and purity was determined using a modified tricine SDS-PAGE system. The peptide isolated indicated the presence of multiple disulfide bonds in a tight β-defensin cystine conformation. An IC50 value of 26 nM was determined for total channel inhibition on MCF-7 cells. The unique putative sodium channel agonist initiating with a cystine bond indicates a divergent evolution to those previously isolated from Bunodosoma species.
- Full Text:
- Date Issued: 2019
Quantifying the accuracy of small subnet-equivalent sampling of IPv4 internet background radiation datasets
- Chindipha, Stones, D, Irwin, Barry V W, Herbert, Alan
- Authors: Chindipha, Stones, D , Irwin, Barry V W , Herbert, Alan
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430271 , vital:72679 , https://doi.org/10.1145/3351108.3351129
- Description: Network telescopes have been used for over a decade to aid in identifying threats by gathering unsolicited network traffic. This Internet Background Radiation (IBR) data has proved to be a significant source of intelligence in combating emerging threats on the Internet at large. Traditionally, operation has required a significant contiguous block of IP addresses. Continued operation of such sensors by researchers and adoption by organisations as part of its operation intelligence is becoming a challenge due to the global shortage of IPv4 addresses. The pressure is on to use allocated IP addresses for operational purposes. Future use of IBR collection methods is likely to be limited to smaller IP address pools, which may not be contiguous. This paper offers a first step towards evaluating the feasibility of such small sensors. An evaluation is conducted of the random sampling of various subnet sized equivalents. The accuracy of observable data is compared against a traditional 'small' IPv4 network telescope using a /24 net-block. Results show that for much of the IBR data, sensors consisting of smaller, non-contiguous blocks of addresses are able to achieve high accuracy rates vs. the base case. While the results obtained given the current nature of IBR, it proves the viability for organisations to utilise free IP addresses within their networks for IBR collection and ultimately the production of Threat intelligence.
- Full Text:
- Date Issued: 2019
- Authors: Chindipha, Stones, D , Irwin, Barry V W , Herbert, Alan
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430271 , vital:72679 , https://doi.org/10.1145/3351108.3351129
- Description: Network telescopes have been used for over a decade to aid in identifying threats by gathering unsolicited network traffic. This Internet Background Radiation (IBR) data has proved to be a significant source of intelligence in combating emerging threats on the Internet at large. Traditionally, operation has required a significant contiguous block of IP addresses. Continued operation of such sensors by researchers and adoption by organisations as part of its operation intelligence is becoming a challenge due to the global shortage of IPv4 addresses. The pressure is on to use allocated IP addresses for operational purposes. Future use of IBR collection methods is likely to be limited to smaller IP address pools, which may not be contiguous. This paper offers a first step towards evaluating the feasibility of such small sensors. An evaluation is conducted of the random sampling of various subnet sized equivalents. The accuracy of observable data is compared against a traditional 'small' IPv4 network telescope using a /24 net-block. Results show that for much of the IBR data, sensors consisting of smaller, non-contiguous blocks of addresses are able to achieve high accuracy rates vs. the base case. While the results obtained given the current nature of IBR, it proves the viability for organisations to utilise free IP addresses within their networks for IBR collection and ultimately the production of Threat intelligence.
- Full Text:
- Date Issued: 2019
Rebellion and revolution
- Authors: Tabensky, Pedro
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305721 , vital:58606 , xlink:href="https://doi.org/10.1080/0969725X.2019.1574085"
- Description: In this piece I will focus on what I think is a central aspect of Albert Camus’s thinking, embodied in the distinction he makes in The Rebel between rebel and revolutionary. His is a philosophy of rebellion and he thinks that revolutions are a distorted expression of our need to rebel against that which we cannot accept. His views should serve as a counterpoint to those who think that an all-or-nothing approach to social change is desirable (those who, for instance, are too quick to justify murderous campaigns allegedly aimed at justice). And the issue here is not that embodied crudely in the reactionary (or conservative)/radical dichotomy. Rather, it is a defence of the need to rebel within limits, not so much to preserve the old against the threat of the new but, instead, to preserve basic human decency from the dark side of outrage, without dismissing what is crucial about outrage and emancipatory struggles.
- Full Text:
- Date Issued: 2019
- Authors: Tabensky, Pedro
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305721 , vital:58606 , xlink:href="https://doi.org/10.1080/0969725X.2019.1574085"
- Description: In this piece I will focus on what I think is a central aspect of Albert Camus’s thinking, embodied in the distinction he makes in The Rebel between rebel and revolutionary. His is a philosophy of rebellion and he thinks that revolutions are a distorted expression of our need to rebel against that which we cannot accept. His views should serve as a counterpoint to those who think that an all-or-nothing approach to social change is desirable (those who, for instance, are too quick to justify murderous campaigns allegedly aimed at justice). And the issue here is not that embodied crudely in the reactionary (or conservative)/radical dichotomy. Rather, it is a defence of the need to rebel within limits, not so much to preserve the old against the threat of the new but, instead, to preserve basic human decency from the dark side of outrage, without dismissing what is crucial about outrage and emancipatory struggles.
- Full Text:
- Date Issued: 2019
Remedies, repentance and the doctrine of election in South African contract law
- Authors: Glover, Graham B
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186712 , vital:44527 , xlink:href="https://hdl.handle.net/10520/EJC-1a756528b2"
- Description: One of the main features of South Africa’s law on remedies for breach of contract is the doctrine of election. In cases where a major breach has occurred, or a cancellation clause entitles the aggrieved party to seek cancellation, the aggrieved party has an election either to cancel or to claim performance, and will be held to that binary choice. In Primat Construction CC v Nelson Mandela Bay Metropolitan Municipality the Supreme Court of Appeal recently recognised an exception to the usual election rule, specifically in cases involving repudiation. In terms of the ‘repentance principle’, a party who experiences repudiation may initially seek performance in the hope that the breaching party will repent of their breach; but if it does not, the aggrieved party may then change its mind and seek cancellation. This essay considers the history of the doctrine of election and the path to the recognition of its qualifier, the repentance principle. Thereafter, the essay poses the question whether it remains desirable for the strict doctrine of election to continue to apply in South African law, bearing in mind that a strict election can have an unduly constraining effect on the interests of the non-breaching (or ‘innocent’) party. This analysis is informed by the broader policy considerations behind the recognition of the repentance principle; the fact that other analogous exceptions to the election rule do exist; and the fact that other jurisdictions do not adopt such a strict approach to the aggrieved party’s choice of remedy.
- Full Text:
- Date Issued: 2019
- Authors: Glover, Graham B
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186712 , vital:44527 , xlink:href="https://hdl.handle.net/10520/EJC-1a756528b2"
- Description: One of the main features of South Africa’s law on remedies for breach of contract is the doctrine of election. In cases where a major breach has occurred, or a cancellation clause entitles the aggrieved party to seek cancellation, the aggrieved party has an election either to cancel or to claim performance, and will be held to that binary choice. In Primat Construction CC v Nelson Mandela Bay Metropolitan Municipality the Supreme Court of Appeal recently recognised an exception to the usual election rule, specifically in cases involving repudiation. In terms of the ‘repentance principle’, a party who experiences repudiation may initially seek performance in the hope that the breaching party will repent of their breach; but if it does not, the aggrieved party may then change its mind and seek cancellation. This essay considers the history of the doctrine of election and the path to the recognition of its qualifier, the repentance principle. Thereafter, the essay poses the question whether it remains desirable for the strict doctrine of election to continue to apply in South African law, bearing in mind that a strict election can have an unduly constraining effect on the interests of the non-breaching (or ‘innocent’) party. This analysis is informed by the broader policy considerations behind the recognition of the repentance principle; the fact that other analogous exceptions to the election rule do exist; and the fact that other jurisdictions do not adopt such a strict approach to the aggrieved party’s choice of remedy.
- Full Text:
- Date Issued: 2019
Research for the people, by the people: The political practice of cognitive justice and transformative learning in environmental social movements
- Authors: Burt, Jane C
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392177 , vital:68728 , xlink:href="https://doi.org/10.3390/su11205611"
- Description: This paper describes how Changing Practice courses, developed by environmental activists in South Africa and based on social learning practice, have seeded cognitive justice action. For the educator-activists who facilitated these courses, it became apparent that we needed a bold emancipatory pedagogy which included cognitive justice issues. This enabled us and the activist-researcher participants to understand the extent to which local, indigenous, and spiritual knowledge had been excluded from water governance. The paper investigates how participants in the ‘Water and Tradition’ change project, established by the Vaal Environmental Justice Alliance (VEJA, engaged with cognitive justice, to demonstrate how African spiritual practice offers a re-visioning of the natural world. Finally, using the tools of critical realist theory, the paper reviews how VEJA bring about transformative social action through their participation in the Changing Practice course.
- Full Text:
- Date Issued: 2019
- Authors: Burt, Jane C
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/392177 , vital:68728 , xlink:href="https://doi.org/10.3390/su11205611"
- Description: This paper describes how Changing Practice courses, developed by environmental activists in South Africa and based on social learning practice, have seeded cognitive justice action. For the educator-activists who facilitated these courses, it became apparent that we needed a bold emancipatory pedagogy which included cognitive justice issues. This enabled us and the activist-researcher participants to understand the extent to which local, indigenous, and spiritual knowledge had been excluded from water governance. The paper investigates how participants in the ‘Water and Tradition’ change project, established by the Vaal Environmental Justice Alliance (VEJA, engaged with cognitive justice, to demonstrate how African spiritual practice offers a re-visioning of the natural world. Finally, using the tools of critical realist theory, the paper reviews how VEJA bring about transformative social action through their participation in the Changing Practice course.
- Full Text:
- Date Issued: 2019
Risk assessment to interpret the physiological host range of Hydrellia egeriae, a biocontrol agent for Egeria densa
- Smith, Rosalie, Mangan, Rosie, Coetzee, Julie A
- Authors: Smith, Rosalie , Mangan, Rosie , Coetzee, Julie A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418053 , vital:71504 , xlink:href="https://doi.org/10.1007/s10526-019-09942-4"
- Description: Egeria densa Planchon (Hydrocharitaceae) is a submerged macrophyte native to South America. It forms part of a new suite of invasive aquatic plants that has benefited from open nutrient-rich freshwater systems following the successful biological control of floating aquatic plants in South Africa. The specificity of the leaf-mining fly, Hydrellia egeriae Rodrigues (Diptera: Ephydridae) was tested, using traditional laboratory host-specificity testing (i.e., no-choice and paired choice). Only one non-target species, Lagarosiphon major Deeming (Hydrocharitaceae) supported larval development during pair-choice tests. In order to avoid the rejection of a safe and potentially effective agent, continuation (i.e., multiple generations) tests were conducted to measure the ability of the non-target species to nutritionally support a population indefinitely. None of these species could sustain a viable agent population for more than three generations. Laboratory host-specificity tests are limited as they exempt certain insect-host behaviours. To enhance the interpretation of host-specificity results, a risk assessment was conducted using agent preference (i.e., choice tests) and performance (i.e., choice and continuation tests) results. The feeding and reproductive risk that H. egeriae poses to non-target species is below 2%. Based on these findings, permission for its release in South Africa has been obtained.
- Full Text:
- Date Issued: 2019
- Authors: Smith, Rosalie , Mangan, Rosie , Coetzee, Julie A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418053 , vital:71504 , xlink:href="https://doi.org/10.1007/s10526-019-09942-4"
- Description: Egeria densa Planchon (Hydrocharitaceae) is a submerged macrophyte native to South America. It forms part of a new suite of invasive aquatic plants that has benefited from open nutrient-rich freshwater systems following the successful biological control of floating aquatic plants in South Africa. The specificity of the leaf-mining fly, Hydrellia egeriae Rodrigues (Diptera: Ephydridae) was tested, using traditional laboratory host-specificity testing (i.e., no-choice and paired choice). Only one non-target species, Lagarosiphon major Deeming (Hydrocharitaceae) supported larval development during pair-choice tests. In order to avoid the rejection of a safe and potentially effective agent, continuation (i.e., multiple generations) tests were conducted to measure the ability of the non-target species to nutritionally support a population indefinitely. None of these species could sustain a viable agent population for more than three generations. Laboratory host-specificity tests are limited as they exempt certain insect-host behaviours. To enhance the interpretation of host-specificity results, a risk assessment was conducted using agent preference (i.e., choice tests) and performance (i.e., choice and continuation tests) results. The feeding and reproductive risk that H. egeriae poses to non-target species is below 2%. Based on these findings, permission for its release in South Africa has been obtained.
- Full Text:
- Date Issued: 2019
Short term stability testing of efavirenz-loaded solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC) dispersions
- Makoni, Pedzisai A, Kasongo, Kasongo W, Walker, Roderick B
- Authors: Makoni, Pedzisai A , Kasongo, Kasongo W , Walker, Roderick B
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183492 , vital:44000 , xlink:href="https://doi.org/10.3390/pharmaceutics11080397"
- Description: The short term stability of efavirenz-loaded solid lipid nanoparticle and nanostructured lipid carrier dispersions was investigated. Hot High Pressure Homogenization with the capability for scale up production was successfully used to manufacture the nanocarriers without the use of toxic organic solvents for the first time. Glyceryl monostearate and Transcutol® HP were used as the solid and liquid lipids. Tween® 80 was used to stabilize the lipid nanocarriers. A Box-Behnken Design was used to identify the optimum operating and production conditions viz., 1100 bar for 3 cycles for the solid lipid nanoparticles and 1500 bar for 5 cycles for nanostructured lipid carriers. The optimized nanocarriers were predicted to exhibit 10% efavirenz loading with 3% and 4% Tween® 80 for solid lipid nanoparticles and nanostructured lipid carriers, respectively. Characterization of the optimized solid lipid nanoparticle and nanostructured lipid carrier formulations in relation to shape, surface morphology, polymorphism, crystallinity and compatibility revealed stable formulations with particle sizes in the nanometer range had been produced. The nanocarriers had excellent efavirenz loading with the encapsulation efficiency >90%. The optimized nanocarriers exhibited biphasic in vitro release patterns with an initial burst release during the initial 0–3 h followed by sustained release over a 24 h period The colloidal systems showed excellent stability in terms of Zeta potential, particle size, polydispersity index and encapsulation efficiency when stored for 8 weeks at 25 °C/60% RH in comparison to when stored at 40 °C/75% RH. The formulations manufactured using the optimized conditions and composition proved to be physically stable as aqueous dispersions.
- Full Text:
- Date Issued: 2019
- Authors: Makoni, Pedzisai A , Kasongo, Kasongo W , Walker, Roderick B
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183492 , vital:44000 , xlink:href="https://doi.org/10.3390/pharmaceutics11080397"
- Description: The short term stability of efavirenz-loaded solid lipid nanoparticle and nanostructured lipid carrier dispersions was investigated. Hot High Pressure Homogenization with the capability for scale up production was successfully used to manufacture the nanocarriers without the use of toxic organic solvents for the first time. Glyceryl monostearate and Transcutol® HP were used as the solid and liquid lipids. Tween® 80 was used to stabilize the lipid nanocarriers. A Box-Behnken Design was used to identify the optimum operating and production conditions viz., 1100 bar for 3 cycles for the solid lipid nanoparticles and 1500 bar for 5 cycles for nanostructured lipid carriers. The optimized nanocarriers were predicted to exhibit 10% efavirenz loading with 3% and 4% Tween® 80 for solid lipid nanoparticles and nanostructured lipid carriers, respectively. Characterization of the optimized solid lipid nanoparticle and nanostructured lipid carrier formulations in relation to shape, surface morphology, polymorphism, crystallinity and compatibility revealed stable formulations with particle sizes in the nanometer range had been produced. The nanocarriers had excellent efavirenz loading with the encapsulation efficiency >90%. The optimized nanocarriers exhibited biphasic in vitro release patterns with an initial burst release during the initial 0–3 h followed by sustained release over a 24 h period The colloidal systems showed excellent stability in terms of Zeta potential, particle size, polydispersity index and encapsulation efficiency when stored for 8 weeks at 25 °C/60% RH in comparison to when stored at 40 °C/75% RH. The formulations manufactured using the optimized conditions and composition proved to be physically stable as aqueous dispersions.
- Full Text:
- Date Issued: 2019
Simulated global increases in atmospheric CO2 alter the tissue composition, but not the growth of some submerged aquatic plant bicarbonate users growing in DIC rich waters
- Hussner, Andreas, Smith, Rosali, Mettler-Altmann, Tabea, Hill, Martin P, Coetzee, Julie A
- Authors: Hussner, Andreas , Smith, Rosali , Mettler-Altmann, Tabea , Hill, Martin P , Coetzee, Julie A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419388 , vital:71640 , xlink:href="https://doi.org/10.1016/j.aquabot.2018.11.009"
- Description: Current global change scenarios predict an increase in atmospheric CO2 from the current 380 ppm to a value ranging from 540 ppm to 960 ppm by the year 2100. The effects of three air CO2 levels (400, 600 and 800 ppm) on five submerged aquatic plants that utilize HCO3− were studied, using the elevated CO2 Open Top Chamber facility at Rhodes University (Grahamstown, South Africa). Plants grew in water with two different initial dissolved inorganic carbon (DIC) concentrations of 1.5 and 3.0 mM. Overall, the growth rates and biomass allocation to roots were not affected by the initial DIC and air CO2, even though differences between the species were found. Furthermore, no overall effects were found on net photosynthesis, chlorophyll and starch content, even though significant effects of CO2 and DIC were observed in some species. In contrast, with increasing DIC and air CO2 a significant global decline in leaf nitrogen content linked with an increased C:N molar ratio was observed. The results indicate that submerged aquatic HCO3− users will be less affected by atmospheric CO2 increases when growing in DIC rich waters, in comparison to obligate CO2 users growing under CO2 limiting conditions as documented in previous studies. However, the changes found in plant nitrogen illustrate that atmospheric CO2 increases will affect nitrogen absorption by submerged plants, with subsequent ecosystem level effects.
- Full Text:
- Date Issued: 2019
- Authors: Hussner, Andreas , Smith, Rosali , Mettler-Altmann, Tabea , Hill, Martin P , Coetzee, Julie A
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419388 , vital:71640 , xlink:href="https://doi.org/10.1016/j.aquabot.2018.11.009"
- Description: Current global change scenarios predict an increase in atmospheric CO2 from the current 380 ppm to a value ranging from 540 ppm to 960 ppm by the year 2100. The effects of three air CO2 levels (400, 600 and 800 ppm) on five submerged aquatic plants that utilize HCO3− were studied, using the elevated CO2 Open Top Chamber facility at Rhodes University (Grahamstown, South Africa). Plants grew in water with two different initial dissolved inorganic carbon (DIC) concentrations of 1.5 and 3.0 mM. Overall, the growth rates and biomass allocation to roots were not affected by the initial DIC and air CO2, even though differences between the species were found. Furthermore, no overall effects were found on net photosynthesis, chlorophyll and starch content, even though significant effects of CO2 and DIC were observed in some species. In contrast, with increasing DIC and air CO2 a significant global decline in leaf nitrogen content linked with an increased C:N molar ratio was observed. The results indicate that submerged aquatic HCO3− users will be less affected by atmospheric CO2 increases when growing in DIC rich waters, in comparison to obligate CO2 users growing under CO2 limiting conditions as documented in previous studies. However, the changes found in plant nitrogen illustrate that atmospheric CO2 increases will affect nitrogen absorption by submerged plants, with subsequent ecosystem level effects.
- Full Text:
- Date Issued: 2019
Spectroscopic and nonlinear optical properties of alkyl thio substituted binuclear phthalocyanines
- Makinde, Zainab O, Louzada, Marcel S, Britton, Jonathan, Nyokong, Tebello, Khene, Samson M
- Authors: Makinde, Zainab O , Louzada, Marcel S , Britton, Jonathan , Nyokong, Tebello , Khene, Samson M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187485 , vital:44661 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.10.022"
- Description: This work presents the spectroscopic and nonlinear optical properties of metal free binuclear and monomeric 4- (pentylthio)phthalocyanine and cobalt 4,5-(bipentylthio)phthalocyanine. Second order nonlinear absorption coefficient (β) values for the complexes were determined and compared.
- Full Text:
- Date Issued: 2019
- Authors: Makinde, Zainab O , Louzada, Marcel S , Britton, Jonathan , Nyokong, Tebello , Khene, Samson M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187485 , vital:44661 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.10.022"
- Description: This work presents the spectroscopic and nonlinear optical properties of metal free binuclear and monomeric 4- (pentylthio)phthalocyanine and cobalt 4,5-(bipentylthio)phthalocyanine. Second order nonlinear absorption coefficient (β) values for the complexes were determined and compared.
- Full Text:
- Date Issued: 2019
Spectroscopic characterization and photodynamic antimicrobial chemotherapy of phthalocyanine-silver triangular nanoprism conjugates when supported on asymmetric polymer membranes
- Mafukidze, Donovan M, Sindelo, Azole, Nyokong, Tebello
- Authors: Mafukidze, Donovan M , Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186927 , vital:44548 , xlink:href="https://doi.org/10.1016/j.saa.2019.04.054"
- Description: Silver triangular nanoprisms were synthesized and conjugated to zinc (ZnPc) and indium (InPc) phthalocyanines prior to embedding in asymmetric membranes. Conjugation of nanoparticles increased triplet state and singlet oxygen quantum yields of the phthalocyanines as well as enhancing photodynamic antimicrobial chemotherapy (PACT) activity against bacteria (S. aureus). The ZnPc derivative showed higher PACT activity when compared to the InPc, possibly due to degradation of the latter in aqueous media.
- Full Text:
- Date Issued: 2019
- Authors: Mafukidze, Donovan M , Sindelo, Azole , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186927 , vital:44548 , xlink:href="https://doi.org/10.1016/j.saa.2019.04.054"
- Description: Silver triangular nanoprisms were synthesized and conjugated to zinc (ZnPc) and indium (InPc) phthalocyanines prior to embedding in asymmetric membranes. Conjugation of nanoparticles increased triplet state and singlet oxygen quantum yields of the phthalocyanines as well as enhancing photodynamic antimicrobial chemotherapy (PACT) activity against bacteria (S. aureus). The ZnPc derivative showed higher PACT activity when compared to the InPc, possibly due to degradation of the latter in aqueous media.
- Full Text:
- Date Issued: 2019
Stability indicating HPLC-ECD method for the analysis of clarithromycin in pharmaceutical dosage forms: Method scaling versus re-validation.
- Makoni, Pedzisai A, Chikukwa, Mellisa, Khamanga, Sandile M, Walker, Roderick B
- Authors: Makoni, Pedzisai A , Chikukwa, Mellisa , Khamanga, Sandile M , Walker, Roderick B
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183387 , vital:43984 , xlink:href="https://doi.org/10.3390/scipharm87040031"
- Description: An isocratic high-performance liquid chromatographic method using electrochemical detection (HPLC-ECD) for the quantitation of clarithromycin (CLA) was developed using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). The method was validated using International Conference on Harmonization (ICH) guidelines with an analytical run time of 20 min. Method re-validation following a change in analytical column was successful in reducing the analytical run time to 13 min, decreasing solvent consumption thus facilitating environmental and financial sustainability. The applicability of using the United States Pharmacopeia (USP) method scaling approach in place of method re-validation using a column with a different L–designation to the original analytical column, was investigated. The scaled method met all USP system suitability requirements for resolution, tailing factor and % relative standard deviation (RSD). The re-validated and scaled method was successfully used to resolve CLA from manufacturing excipients in commercially available dosage forms. Although USP method scaling is only permitted for columns within the same L-designation, these data suggest that it may also be applicable to columns of different designation.
- Full Text:
- Date Issued: 2019
- Authors: Makoni, Pedzisai A , Chikukwa, Mellisa , Khamanga, Sandile M , Walker, Roderick B
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183387 , vital:43984 , xlink:href="https://doi.org/10.3390/scipharm87040031"
- Description: An isocratic high-performance liquid chromatographic method using electrochemical detection (HPLC-ECD) for the quantitation of clarithromycin (CLA) was developed using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). The method was validated using International Conference on Harmonization (ICH) guidelines with an analytical run time of 20 min. Method re-validation following a change in analytical column was successful in reducing the analytical run time to 13 min, decreasing solvent consumption thus facilitating environmental and financial sustainability. The applicability of using the United States Pharmacopeia (USP) method scaling approach in place of method re-validation using a column with a different L–designation to the original analytical column, was investigated. The scaled method met all USP system suitability requirements for resolution, tailing factor and % relative standard deviation (RSD). The re-validated and scaled method was successfully used to resolve CLA from manufacturing excipients in commercially available dosage forms. Although USP method scaling is only permitted for columns within the same L-designation, these data suggest that it may also be applicable to columns of different designation.
- Full Text:
- Date Issued: 2019