Sex, gender and Uvalo/Letswalo centred spirituality
- Magadla, Siphokazi, Magoqwana, Babalwa, Motsemme, Nthabiseng, Mohoto, Lieketso
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng , Mohoto, Lieketso
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298663 , vital:57725 , xlink:href="https://doi.org/10.1080/02589001.2021.1909711"
- Description: In Male Daughters, Female Husbands (1987) Amadiume argues that the female orientation of Nnobi society and its emphasis on female industriousness is ‘derived from goddess Idemili – the ancestral religious deity’ (27). While Christianity dominates the outlook and conservatism of the post-colonial African state, we are seeing a growing public presence of African spiritual practitioners in southern Africa. The interview with Lieketso Gogo Mapitsi Mohoto reflects on her journey of becoming a healer. She uses the concept of ‘uvalo' to argue for deeper connected spiritual awareness within this practice of healing. Using the Nguni concept of uvalo, she refers to the fluid meaning of intuition also known as Umbilini among Xhosa-speaking people, while Sesotho speakers call it Letswalo. This intimate connection with the Divine can sometimes mean a sense of fear for ordinary people, while it promotes a deep sense of knowing for the spiritually conscious. Gogo Mapitsi's connections between spirituality and land, speak to Amadiume’s matrifocal understanding of productivity as linked to the goddess Idemili in Nnobi histories. Gogo Mapitsi reminds us that the multiple health, economic, psychological crises we face today are linked 'to how uvalo works.' She tells us that the 'cultivation of that inner knowing and the cultivation of trust in that knowing' is central to how a Sangoma understands and responds to the needs of their society.
- Full Text:
- Date Issued: 2021
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng , Mohoto, Lieketso
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298663 , vital:57725 , xlink:href="https://doi.org/10.1080/02589001.2021.1909711"
- Description: In Male Daughters, Female Husbands (1987) Amadiume argues that the female orientation of Nnobi society and its emphasis on female industriousness is ‘derived from goddess Idemili – the ancestral religious deity’ (27). While Christianity dominates the outlook and conservatism of the post-colonial African state, we are seeing a growing public presence of African spiritual practitioners in southern Africa. The interview with Lieketso Gogo Mapitsi Mohoto reflects on her journey of becoming a healer. She uses the concept of ‘uvalo' to argue for deeper connected spiritual awareness within this practice of healing. Using the Nguni concept of uvalo, she refers to the fluid meaning of intuition also known as Umbilini among Xhosa-speaking people, while Sesotho speakers call it Letswalo. This intimate connection with the Divine can sometimes mean a sense of fear for ordinary people, while it promotes a deep sense of knowing for the spiritually conscious. Gogo Mapitsi's connections between spirituality and land, speak to Amadiume’s matrifocal understanding of productivity as linked to the goddess Idemili in Nnobi histories. Gogo Mapitsi reminds us that the multiple health, economic, psychological crises we face today are linked 'to how uvalo works.' She tells us that the 'cultivation of that inner knowing and the cultivation of trust in that knowing' is central to how a Sangoma understands and responds to the needs of their society.
- Full Text:
- Date Issued: 2021
Solar Driven Photocatalytic Activity of Porphyrin Sensitized TiO2
- Otieno, Sebastien, Lanterna, Anabel E, Mack, John, Derese, Solomon, Amuhaya, Edith K, Nyokong, Tebello, Scaiano, Juan C
- Authors: Otieno, Sebastien , Lanterna, Anabel E , Mack, John , Derese, Solomon , Amuhaya, Edith K , Nyokong, Tebello , Scaiano, Juan C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190612 , vital:45010 , xlink:href="https://doi.org/10.3390/molecules26113131"
- Description: The absence of a secure long-term sustainable energy supply is recognized as a major worldwide technological challenge. The generation of H2 through photocatalysis is an environmentally friendly alternative that can help solve the energy problem. Thus, the development of semiconductor materials that can absorb solar light is an attractive approach. TiO2 has a wide bandgap that suffers from no activity in the visible spectrum, limiting its use of solar radiation. In this research, the semiconductor absorption profile was extended into the visible region of the solar spectrum by preparing porphyrin-TiO2 (P-TiO2 ) composites of meso-tetra(4-bromophenyl)porphyrin (PP1) and meso-tetra(5-bromo-2-thienyl)porphyrin (PP2) and their In(III), Zn(II) and Ga(III) metal complexes. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed on the porphyrins to gain insight into their electron injection capability. The results demonstrate that P-TiO2 systems merit further in-depth study for applications that require efficient photocatalytic H2 generation.
- Full Text:
- Date Issued: 2021
- Authors: Otieno, Sebastien , Lanterna, Anabel E , Mack, John , Derese, Solomon , Amuhaya, Edith K , Nyokong, Tebello , Scaiano, Juan C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190612 , vital:45010 , xlink:href="https://doi.org/10.3390/molecules26113131"
- Description: The absence of a secure long-term sustainable energy supply is recognized as a major worldwide technological challenge. The generation of H2 through photocatalysis is an environmentally friendly alternative that can help solve the energy problem. Thus, the development of semiconductor materials that can absorb solar light is an attractive approach. TiO2 has a wide bandgap that suffers from no activity in the visible spectrum, limiting its use of solar radiation. In this research, the semiconductor absorption profile was extended into the visible region of the solar spectrum by preparing porphyrin-TiO2 (P-TiO2 ) composites of meso-tetra(4-bromophenyl)porphyrin (PP1) and meso-tetra(5-bromo-2-thienyl)porphyrin (PP2) and their In(III), Zn(II) and Ga(III) metal complexes. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed on the porphyrins to gain insight into their electron injection capability. The results demonstrate that P-TiO2 systems merit further in-depth study for applications that require efficient photocatalytic H2 generation.
- Full Text:
- Date Issued: 2021
Synthesis of a near infrared-actuated phthalocyanine-lipid vesicle system for augmented photodynamic therapy
- Nwahara, Namdi, Managa, Muthumuni, Stoffels, Mihlali, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello
- Authors: Nwahara, Namdi , Managa, Muthumuni , Stoffels, Mihlali , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185395 , vital:44383 , xlink:href="https://doi.org/10.1016/j.synthmet.2021.116811"
- Description: The efficacy of photodynamic therapy (PDT) is often limited by the poor bio-distributive properties of conventional photosensitizers and the local hypoxic microenvironment that characterises most solid tumours. Herein, a novel in situ oxygenic lipid formulation for photodynamic therapy (PDT) is reported. Such a hybrid was synthesized by adsorbing bimetallic nanozyme, MnO2@PtNPs (NPs = nanoparticles) onto graphene quantum dots (GQDs) – zinc (II) phthalocyanine conjugates, followed by liposomal encapsulation, affording it enhanced water solubility. The MnO2@PtNPs, which are is shown to possess excellent catalase-like properties surpassing that of MnO2 or PtNPs alone, serves to catalyze H2O2 to O2, while the zinc (II) phthalocyanine (1) serves to transform the formed oxygen to generate cytotoxic singlet oxygen immediately. We show that by combining each function of the respective building blocks, the as-synthesized 1-GQDs-MnO2@PtNPs-liposomes not only maintains the properties of oxygen supplementation through H2O2 catalysis but also displays cooperative properties for enhanced singlet oxygen production. Consequently, a remarkably improved PDT efficacy was observed for 1-GQDs-MnO2@PtNPs-liposomes in both normoxia and hypoxia. These results demonstrate the potential applicability of such nanozyme constituted 1-GQDs-MnO2@PtNPs-liposomes for achieving tumour treatment in hypoxic conditions by PDT.
- Full Text:
- Date Issued: 2021
- Authors: Nwahara, Namdi , Managa, Muthumuni , Stoffels, Mihlali , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185395 , vital:44383 , xlink:href="https://doi.org/10.1016/j.synthmet.2021.116811"
- Description: The efficacy of photodynamic therapy (PDT) is often limited by the poor bio-distributive properties of conventional photosensitizers and the local hypoxic microenvironment that characterises most solid tumours. Herein, a novel in situ oxygenic lipid formulation for photodynamic therapy (PDT) is reported. Such a hybrid was synthesized by adsorbing bimetallic nanozyme, MnO2@PtNPs (NPs = nanoparticles) onto graphene quantum dots (GQDs) – zinc (II) phthalocyanine conjugates, followed by liposomal encapsulation, affording it enhanced water solubility. The MnO2@PtNPs, which are is shown to possess excellent catalase-like properties surpassing that of MnO2 or PtNPs alone, serves to catalyze H2O2 to O2, while the zinc (II) phthalocyanine (1) serves to transform the formed oxygen to generate cytotoxic singlet oxygen immediately. We show that by combining each function of the respective building blocks, the as-synthesized 1-GQDs-MnO2@PtNPs-liposomes not only maintains the properties of oxygen supplementation through H2O2 catalysis but also displays cooperative properties for enhanced singlet oxygen production. Consequently, a remarkably improved PDT efficacy was observed for 1-GQDs-MnO2@PtNPs-liposomes in both normoxia and hypoxia. These results demonstrate the potential applicability of such nanozyme constituted 1-GQDs-MnO2@PtNPs-liposomes for achieving tumour treatment in hypoxic conditions by PDT.
- Full Text:
- Date Issued: 2021
Synthesis, theoretical calculations and laser flash photolysis studies of selected amphiphilic porphyrin derivatives used as biofilm photodegradative materials
- Openda, Yolande I, Ngoy, Bokolombe P, Muva, Jules T, Nyokong, Tebello
- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Muva, Jules T , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190589 , vital:45008 , xlink:href="https://doi.org/10.1039/D1NJ02651H"
- Description: Photodynamic antimicrobial activities of gallium and indium porphyrins as well as their quaternized derivatives have been investigated against S. aureus and E. coli biofilms, as well as on their planktonic (free floating) cells using a light emitting diode lamp at 415 nm. The studied photosensitizers show considerable ability to generate singlet oxygen and the quaternized molecules 2a and 3a are potential photodynamic antimicrobial chemotherapy (PACT) agents with log10 colony forming units >9 for E. coli and S. aureus planktonic cells. The quaternized derivatives are found to have higher ability to significantly suppress the biofilms of both S. aureus and E. coli in vitro. Therefore, this demonstrates that they are potentially suitable photosensitive agents for PACT use. The TD-B3LYP/LanL2DZ calculations were performed to evaluate the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. Our study shows excellent agreement between time-dependent density-functional theory (TD-DFT) excited energies and experimental S1 > S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-visible spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO−1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.
- Full Text:
- Date Issued: 2021
- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Muva, Jules T , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190589 , vital:45008 , xlink:href="https://doi.org/10.1039/D1NJ02651H"
- Description: Photodynamic antimicrobial activities of gallium and indium porphyrins as well as their quaternized derivatives have been investigated against S. aureus and E. coli biofilms, as well as on their planktonic (free floating) cells using a light emitting diode lamp at 415 nm. The studied photosensitizers show considerable ability to generate singlet oxygen and the quaternized molecules 2a and 3a are potential photodynamic antimicrobial chemotherapy (PACT) agents with log10 colony forming units >9 for E. coli and S. aureus planktonic cells. The quaternized derivatives are found to have higher ability to significantly suppress the biofilms of both S. aureus and E. coli in vitro. Therefore, this demonstrates that they are potentially suitable photosensitive agents for PACT use. The TD-B3LYP/LanL2DZ calculations were performed to evaluate the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. Our study shows excellent agreement between time-dependent density-functional theory (TD-DFT) excited energies and experimental S1 > S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-visible spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO−1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.
- Full Text:
- Date Issued: 2021
Terminaliamide, a new ceramide and other phytoconstituents from the roots of Terminalia mantaly H. Perrier and their biological activities
- Mbosso, Emmanuel, Siwe-Noundou, Xavier, Fannang, Simon, Song, Achille M, Assob, Jules C N, Hoppe, Heinrich, Krause, Rui W M
- Authors: Mbosso, Emmanuel , Siwe-Noundou, Xavier , Fannang, Simon , Song, Achille M , Assob, Jules C N , Hoppe, Heinrich , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191779 , vital:45163 , xlink:href="https://doi.org/10.1080/14786419.2019.1647425"
- Description: Terminaliamide (1), a new ceramide was isolated from the roots of Terminalia mantaly H. Perrier (Combretaceae) along with 4 known compounds (2–5). The structures of the compounds were elucidated using 1D and 2D NMR spectroscopy analysis and mass spectrometry. Compound 1 exhibited moderated antibacterial activity towards Staphylococcus aureus with MIC value of 62.5 μg/mL. The crude MeOH extract (TMr) highly reduced Plasmodium falciparum growth with an IC50 value of 10.11 μg/mL, while hexane fraction (F1) highly reduced Trypanosoma brucei brucei growth with an IC50 value of 5.60 µg/mL. All tested samples presented little or no in vitro cytotoxicity on HeLa cell line. The present work confirms that T. mantaly is medicinally important and may be used effectively as an antimicrobial, an antiplasmodial and an antitrypanosomial with promising therapeutic index.
- Full Text:
- Date Issued: 2021
- Authors: Mbosso, Emmanuel , Siwe-Noundou, Xavier , Fannang, Simon , Song, Achille M , Assob, Jules C N , Hoppe, Heinrich , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191779 , vital:45163 , xlink:href="https://doi.org/10.1080/14786419.2019.1647425"
- Description: Terminaliamide (1), a new ceramide was isolated from the roots of Terminalia mantaly H. Perrier (Combretaceae) along with 4 known compounds (2–5). The structures of the compounds were elucidated using 1D and 2D NMR spectroscopy analysis and mass spectrometry. Compound 1 exhibited moderated antibacterial activity towards Staphylococcus aureus with MIC value of 62.5 μg/mL. The crude MeOH extract (TMr) highly reduced Plasmodium falciparum growth with an IC50 value of 10.11 μg/mL, while hexane fraction (F1) highly reduced Trypanosoma brucei brucei growth with an IC50 value of 5.60 µg/mL. All tested samples presented little or no in vitro cytotoxicity on HeLa cell line. The present work confirms that T. mantaly is medicinally important and may be used effectively as an antimicrobial, an antiplasmodial and an antitrypanosomial with promising therapeutic index.
- Full Text:
- Date Issued: 2021
Terminaliamide, a new ceramide and other phytoconstituents from the roots of Terminalia mantaly H. Perrier and their biological activities
- Mbosso Teinkela, Jean E, Siwe-Noundou, Xavier, Fannang, Simone, Song, Achille M, Nguedia Assob, Jules C, Hoppe, Heinrich C, Krause, Rui W M
- Authors: Mbosso Teinkela, Jean E , Siwe-Noundou, Xavier , Fannang, Simone , Song, Achille M , Nguedia Assob, Jules C , Hoppe, Heinrich C , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194095 , vital:45422 , xlink:href="https://doi.org/10.1080/14786419.2019.1647425"
- Description: Terminaliamide (1), a new ceramide was isolated from the roots of Terminalia mantaly H. Perrier (Combretaceae) along with 4 known compounds (2–5). The structures of the compounds were elucidated using 1D and 2D NMR spectroscopy analysis and mass spectrometry. Compound 1 exhibited moderated antibacterial activity towards Staphylococcus aureus with MIC value of 62.5 μg/mL. The crude MeOH extract (TMr) highly reduced Plasmodium falciparum growth with an IC50 value of 10.11 μg/mL, while hexane fraction (F1) highly reduced Trypanosoma brucei brucei growth with an IC50 value of 5.60 µg/mL. All tested samples presented little or no in vitro cytotoxicity on HeLa cell line. The present work confirms that T. mantaly is medicinally important and may be used effectively as an antimicrobial, an antiplasmodial and an antitrypanosomial with promising therapeutic index.
- Full Text:
- Date Issued: 2021
- Authors: Mbosso Teinkela, Jean E , Siwe-Noundou, Xavier , Fannang, Simone , Song, Achille M , Nguedia Assob, Jules C , Hoppe, Heinrich C , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194095 , vital:45422 , xlink:href="https://doi.org/10.1080/14786419.2019.1647425"
- Description: Terminaliamide (1), a new ceramide was isolated from the roots of Terminalia mantaly H. Perrier (Combretaceae) along with 4 known compounds (2–5). The structures of the compounds were elucidated using 1D and 2D NMR spectroscopy analysis and mass spectrometry. Compound 1 exhibited moderated antibacterial activity towards Staphylococcus aureus with MIC value of 62.5 μg/mL. The crude MeOH extract (TMr) highly reduced Plasmodium falciparum growth with an IC50 value of 10.11 μg/mL, while hexane fraction (F1) highly reduced Trypanosoma brucei brucei growth with an IC50 value of 5.60 µg/mL. All tested samples presented little or no in vitro cytotoxicity on HeLa cell line. The present work confirms that T. mantaly is medicinally important and may be used effectively as an antimicrobial, an antiplasmodial and an antitrypanosomial with promising therapeutic index.
- Full Text:
- Date Issued: 2021
The antibacterial and antifungal properties of neutral, octacationic and hexadecacationic Zn phthalocyanines when conjugated to silver nanoparticles
- Mapukata, Sibusisiwe, Sen, Pinar, Osifeko, Olawale L, Nyokong, Tebello
- Authors: Mapukata, Sibusisiwe , Sen, Pinar , Osifeko, Olawale L , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185667 , vital:44408 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102361"
- Description: The syntheses and characterization of novel octacationic and hexadecacationic Pcs is reported. With the aim of enhancing singlet oxygen generation efficiencies and hence antimicrobial activities, these Pcs (including their neutral counterpart) are conjugated to Ag nanoparticles (AgNPs). The obtained results show that the conjugate composed of the neutral Pc has a higher loading of Pcs as well as a greater singlet oxygen quantum yield enhancement (in the presence of AgNPs) in DMSO. The antimicrobial efficiencies of the Pcs and their conjugates were evaluated and compared on S. aureus, E. coli and C. albicans. The cationic Pcs possess better activity than the neutral Pc against all the microorganisms with the hexadecacationic Pc being the best. This work therefore demonstrates that increase in the number of cationic charges on the reported Pcs results in enhanced antimicrobial activities, which is maintained even when conjugated to Ag nanoparticles. The high activity and lack of selectivity of the cationic Pcs when conjugated to Ag NPs against different microorganisms make them good candidates for real life antimicrobial treatments.
- Full Text:
- Date Issued: 2021
- Authors: Mapukata, Sibusisiwe , Sen, Pinar , Osifeko, Olawale L , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185667 , vital:44408 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102361"
- Description: The syntheses and characterization of novel octacationic and hexadecacationic Pcs is reported. With the aim of enhancing singlet oxygen generation efficiencies and hence antimicrobial activities, these Pcs (including their neutral counterpart) are conjugated to Ag nanoparticles (AgNPs). The obtained results show that the conjugate composed of the neutral Pc has a higher loading of Pcs as well as a greater singlet oxygen quantum yield enhancement (in the presence of AgNPs) in DMSO. The antimicrobial efficiencies of the Pcs and their conjugates were evaluated and compared on S. aureus, E. coli and C. albicans. The cationic Pcs possess better activity than the neutral Pc against all the microorganisms with the hexadecacationic Pc being the best. This work therefore demonstrates that increase in the number of cationic charges on the reported Pcs results in enhanced antimicrobial activities, which is maintained even when conjugated to Ag nanoparticles. The high activity and lack of selectivity of the cationic Pcs when conjugated to Ag NPs against different microorganisms make them good candidates for real life antimicrobial treatments.
- Full Text:
- Date Issued: 2021
The antibody assisted detection of HER2 on a cobalt porphyrin binuclear framework and gold functionalized graphene quantum dots modified electrode
- Centane, Sixole, Nyokong, Tebello
- Authors: Centane, Sixole , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185931 , vital:44449 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.114908"
- Description: In this work a novel simple, inexpensive and highly sensitive approach for the antibody assisted detection of the human epidermal growth factor receptor 2 (HER2) is presented. Three sensors using carboxylic group containing gold functionalized graphene quantum dots (SNGQDs@AuNPs), CoP-BNF (cobalt porphyrin binuclear framework) and CoP-BNF/SNGQDs@AuNPs (the conjugate) nanocomposites on a GCE were designed. The sensors were fabricated by covalent immobilization of the antibody to the GCE via an amide bond. The modified GCE was characterized using cyclic voltammetry and impedance spectroscopy. The performance of the sensors was assessed using electrochemical impedance spectroscopy. The selective recognition of the antibody towards HER2 on the electrode led to an increase of the electron transfer resistance (Rct). The different modified electrodes had low detection limit values: 0.0327 ng/mL, 0.0454 ng/mL and 0.1072 ng/mL towards the detection of HER2. The sensors showed good stability and reproducibility. The sensors showed promising potential in clinical applicability, in the detection of HER2 protein in human serum.
- Full Text:
- Date Issued: 2021
- Authors: Centane, Sixole , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185931 , vital:44449 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.114908"
- Description: In this work a novel simple, inexpensive and highly sensitive approach for the antibody assisted detection of the human epidermal growth factor receptor 2 (HER2) is presented. Three sensors using carboxylic group containing gold functionalized graphene quantum dots (SNGQDs@AuNPs), CoP-BNF (cobalt porphyrin binuclear framework) and CoP-BNF/SNGQDs@AuNPs (the conjugate) nanocomposites on a GCE were designed. The sensors were fabricated by covalent immobilization of the antibody to the GCE via an amide bond. The modified GCE was characterized using cyclic voltammetry and impedance spectroscopy. The performance of the sensors was assessed using electrochemical impedance spectroscopy. The selective recognition of the antibody towards HER2 on the electrode led to an increase of the electron transfer resistance (Rct). The different modified electrodes had low detection limit values: 0.0327 ng/mL, 0.0454 ng/mL and 0.1072 ng/mL towards the detection of HER2. The sensors showed good stability and reproducibility. The sensors showed promising potential in clinical applicability, in the detection of HER2 protein in human serum.
- Full Text:
- Date Issued: 2021
The complex relationship between asset wealth, adaptation, and diversification in tropical fisheries
- Taylor, Sarah F, Aswani, Shankar, Jiddawi, Narriman, Coupland, Jack, James, Phillip, Kelly, Stephen, Kizenga, Hellen, Roberts, Michael, Popova, Ekaterina
- Authors: Taylor, Sarah F , Aswani, Shankar , Jiddawi, Narriman , Coupland, Jack , James, Phillip , Kelly, Stephen , Kizenga, Hellen , Roberts, Michael , Popova, Ekaterina
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403475 , vital:69964 , xlink:href="https://doi.org/10.1016/j.ocecoaman.2021.105808"
- Description: Marine small-scale fisheries are complex social and ecological systems that are currently pressurised by climate change, increasing demand for food, and expectation to sustain livelihoods. Species diversification and occupational diversification are often offered as adaptation strategies to increase the resilience of these fisheries to natural and economic shocks. However, little is known about the nature of species diversification within marine tropical fisheries. Based on 293 interviews with artisanal fishers from six coastal communities located at the isles of Zanzibar, Pemba, Mafia, and Mainland Tanga in Tanzania - we assess if fishers with the highest level of species diversification are the most financially secure and able to adapt to changes in the fishing industry. By creating an Asset Wealth Index (AWI) based on a Multiple Correspondence Approach (MCA), we investigate the relative levels of adaptive capacity and fishery connectivity within the different regional wealth quartiles. We find that less wealthy fishers target fewer species, making them less able to absorb changes in management measures focused on species, area, and closures. Likewise, fishers with higher wealth scores and higher adaptive capacity are able to better absorb the short-term losses of fisheries closures when compared to those with lower wealth and adaptive scores reliant on higher levels of fishery connectivity.
- Full Text:
- Date Issued: 2021
The complex relationship between asset wealth, adaptation, and diversification in tropical fisheries
- Authors: Taylor, Sarah F , Aswani, Shankar , Jiddawi, Narriman , Coupland, Jack , James, Phillip , Kelly, Stephen , Kizenga, Hellen , Roberts, Michael , Popova, Ekaterina
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403475 , vital:69964 , xlink:href="https://doi.org/10.1016/j.ocecoaman.2021.105808"
- Description: Marine small-scale fisheries are complex social and ecological systems that are currently pressurised by climate change, increasing demand for food, and expectation to sustain livelihoods. Species diversification and occupational diversification are often offered as adaptation strategies to increase the resilience of these fisheries to natural and economic shocks. However, little is known about the nature of species diversification within marine tropical fisheries. Based on 293 interviews with artisanal fishers from six coastal communities located at the isles of Zanzibar, Pemba, Mafia, and Mainland Tanga in Tanzania - we assess if fishers with the highest level of species diversification are the most financially secure and able to adapt to changes in the fishing industry. By creating an Asset Wealth Index (AWI) based on a Multiple Correspondence Approach (MCA), we investigate the relative levels of adaptive capacity and fishery connectivity within the different regional wealth quartiles. We find that less wealthy fishers target fewer species, making them less able to absorb changes in management measures focused on species, area, and closures. Likewise, fishers with higher wealth scores and higher adaptive capacity are able to better absorb the short-term losses of fisheries closures when compared to those with lower wealth and adaptive scores reliant on higher levels of fishery connectivity.
- Full Text:
- Date Issued: 2021
The cultural significance of plant-fiber crafts in Southern Africa: a comparative study of Eswatini, Malawi, and Zimbabwe
- Pullanikkatil, Deepa, Thondhlana, Gladman, Shackleton, Charlie M
- Authors: Pullanikkatil, Deepa , Thondhlana, Gladman , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399860 , vital:69564 , xlink:href="https://doi.org/10.1080/14728028.2021.1998797"
- Description: Traditional handicrafts made from various plant materials are produced by most cultures around the world. Many originated through symbolic and utilitarian needs that became ritualized through time, thereby gradually attaining greater value as cultural items or symbols rather than solely functional ones. Here we report on a survey of 343 crafters across Eswatini, Malawi, and Zimbabwe in southern Africa regarding the cultural uses and significance of the items they make from wild plant fibers and sell to local communities or tourists. The plant materials used were largely dictated by tradition and local availability and were crafted into a diverse range of products including baskets, mats, brooms, storage containers, hats, fish traps, ornaments, and furniture. Many products had uses and cultural significance at major ceremonies or rituals, such as weddings, funerals, initiation, and divination. The preparation and design of the different crafts were influenced by tradition as well as market demand as indicated by tourist fashions and advice provided by government or non-government agencies to boost income generation from crafts. Although the crafting of cultural objects is increasingly commercialized and subject to the tastes and fashions of tourist markets in the region, the traditional and cultural significance of such artifacts remains widely recognized and valued.
- Full Text:
- Date Issued: 2021
- Authors: Pullanikkatil, Deepa , Thondhlana, Gladman , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399860 , vital:69564 , xlink:href="https://doi.org/10.1080/14728028.2021.1998797"
- Description: Traditional handicrafts made from various plant materials are produced by most cultures around the world. Many originated through symbolic and utilitarian needs that became ritualized through time, thereby gradually attaining greater value as cultural items or symbols rather than solely functional ones. Here we report on a survey of 343 crafters across Eswatini, Malawi, and Zimbabwe in southern Africa regarding the cultural uses and significance of the items they make from wild plant fibers and sell to local communities or tourists. The plant materials used were largely dictated by tradition and local availability and were crafted into a diverse range of products including baskets, mats, brooms, storage containers, hats, fish traps, ornaments, and furniture. Many products had uses and cultural significance at major ceremonies or rituals, such as weddings, funerals, initiation, and divination. The preparation and design of the different crafts were influenced by tradition as well as market demand as indicated by tourist fashions and advice provided by government or non-government agencies to boost income generation from crafts. Although the crafting of cultural objects is increasingly commercialized and subject to the tastes and fashions of tourist markets in the region, the traditional and cultural significance of such artifacts remains widely recognized and valued.
- Full Text:
- Date Issued: 2021
The distribution of selected woody invasive alien species in small towns in the Eastern Cape, South Africa
- Mabusela, A, Shackleton, Charlie M, Gewdla, Nanamhla
- Authors: Mabusela, A , Shackleton, Charlie M , Gewdla, Nanamhla
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401289 , vital:69723 , xlink:href="https://doi.org/10.1016/j.sajb.2021.05.019"
- Description: The potential and real negative and positive effects of invasive alien species (IAS) are increasingly recognised by researchers, land managers and decision-makers. However, most of the research and knowledge stems from understandings developed from rural and natural landscapes, with relatively little derived from studies in urban settings. Small towns in particular pose a novel suite of conditions that make the study and mangment of IAS particularly pressing. Here we examined the distribution of seven woody IAS (Acacia mearnsii, Cestrum laevigatum, Eucalyptus spp., Lantana camara, Melia azedarach, Senna didymobotrya and Solanaum mauritianum) within and between five small towns in the Eastern Cape via means of drive-by road surveys of every street in each town. Across the five towns and seven IAS 4,307 individuals were recorded, with the highest densities found in the two more coastal towns. Almost two-thirds (63%) of the IAS were located in residential properties, 24 % in public spaces and 13 % on road verges, closely mirroring the proportional area of these landuses. Within the residential landuse zone specifically, the townships had between 41 % and 61 % of all the recorded IAS plants per town, followed by the affluent neighbourhoods (22 – 41 %) and lastly, the RDP neighbourhoods (6 – 32 %). Cestrum laevigatum was the most abundant woody IAS across the five towns as a whole (1,783 inviduals). The second-most abundant species was M. azedarach (914 stems) and the least recorded was S. mauritianum (44). Additionally, there were differences in the general distribution of the seven species across residential neighbourhoods, with C. laevigatum (71.2 %), M. azedarach (49.3 %) and S. mauritianum (60.0 %) concentrated in township neighbourhoods, whilst A. mearnsii (66.4 %), L. camara (64.1 %) and Eucalyptus spp. (48.6 %) were most common in the affluent neighbourhoods. This study confirms that woody IAS are widespread in small towns of the region, but that they are unevenly distributed between towns and landuses within towns, indicating the need for local-scale inventories and management.
- Full Text:
- Date Issued: 2021
- Authors: Mabusela, A , Shackleton, Charlie M , Gewdla, Nanamhla
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401289 , vital:69723 , xlink:href="https://doi.org/10.1016/j.sajb.2021.05.019"
- Description: The potential and real negative and positive effects of invasive alien species (IAS) are increasingly recognised by researchers, land managers and decision-makers. However, most of the research and knowledge stems from understandings developed from rural and natural landscapes, with relatively little derived from studies in urban settings. Small towns in particular pose a novel suite of conditions that make the study and mangment of IAS particularly pressing. Here we examined the distribution of seven woody IAS (Acacia mearnsii, Cestrum laevigatum, Eucalyptus spp., Lantana camara, Melia azedarach, Senna didymobotrya and Solanaum mauritianum) within and between five small towns in the Eastern Cape via means of drive-by road surveys of every street in each town. Across the five towns and seven IAS 4,307 individuals were recorded, with the highest densities found in the two more coastal towns. Almost two-thirds (63%) of the IAS were located in residential properties, 24 % in public spaces and 13 % on road verges, closely mirroring the proportional area of these landuses. Within the residential landuse zone specifically, the townships had between 41 % and 61 % of all the recorded IAS plants per town, followed by the affluent neighbourhoods (22 – 41 %) and lastly, the RDP neighbourhoods (6 – 32 %). Cestrum laevigatum was the most abundant woody IAS across the five towns as a whole (1,783 inviduals). The second-most abundant species was M. azedarach (914 stems) and the least recorded was S. mauritianum (44). Additionally, there were differences in the general distribution of the seven species across residential neighbourhoods, with C. laevigatum (71.2 %), M. azedarach (49.3 %) and S. mauritianum (60.0 %) concentrated in township neighbourhoods, whilst A. mearnsii (66.4 %), L. camara (64.1 %) and Eucalyptus spp. (48.6 %) were most common in the affluent neighbourhoods. This study confirms that woody IAS are widespread in small towns of the region, but that they are unevenly distributed between towns and landuses within towns, indicating the need for local-scale inventories and management.
- Full Text:
- Date Issued: 2021
The effects of elevated atmospheric CO2 concentration on the biological control of invasive aquatic weeds
- Baso, Nompumelelo C, Coetzee, Julie A, Ripley, Brad S, Hill, Martin P
- Authors: Baso, Nompumelelo C , Coetzee, Julie A , Ripley, Brad S , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419423 , vital:71643 , xlink:href="https://doi.org/10.1016/j.aquabot.2020.103348"
- Description: There has been a rapid increase in atmospheric CO2 concentration, from pre-industrial values of 280 ppm to more than 400 ppm currently, and this is expected to double by the end of the 21st century. Studies have shown that plants grown at elevated CO2 concentrations have increased growth rates and invest more in carbon-based defences. This has important implications for the management of invasive alien plants, especially using biological control which is mostly dependent on herbivorous insects. The aim of this study was to investigate the effects of elevated atmospheric CO2 on the biological control of four invasive aquatic weeds (Azolla filiculoides, Salvinia molesta, Pistia stratiotes and Myriophyllum aquaticum). These species are currently under successful control by their respective biological control agents (Stenopelmus rufinasus, Cyrtobagous salviniae, Neohydronomus affinis, and Lysathia sp.) in South Africa. The plant species were grown in a two factorial design experiment, where atmospheric CO2 concentrations were set at ambient (400 ppm) or elevated (800 ppm), and plants were either subjected to or not subjected to herbivory by their target biological control agents. There was an overall increase in biomass production and C:N across all species at elevated CO2, both in the absence and presence of biological control, although C:N of M. aquaticum and biomass of A. filiculoides with herbivory were not constant with this trend. Insect feeding damage was reduced by elevated CO2, except for S. molesta. Thus, we can expect that plants will respond differently to CO2 increase, but the general trend suggests that these species will become more challenging to manage through biological control in future.
- Full Text:
- Date Issued: 2021
- Authors: Baso, Nompumelelo C , Coetzee, Julie A , Ripley, Brad S , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419423 , vital:71643 , xlink:href="https://doi.org/10.1016/j.aquabot.2020.103348"
- Description: There has been a rapid increase in atmospheric CO2 concentration, from pre-industrial values of 280 ppm to more than 400 ppm currently, and this is expected to double by the end of the 21st century. Studies have shown that plants grown at elevated CO2 concentrations have increased growth rates and invest more in carbon-based defences. This has important implications for the management of invasive alien plants, especially using biological control which is mostly dependent on herbivorous insects. The aim of this study was to investigate the effects of elevated atmospheric CO2 on the biological control of four invasive aquatic weeds (Azolla filiculoides, Salvinia molesta, Pistia stratiotes and Myriophyllum aquaticum). These species are currently under successful control by their respective biological control agents (Stenopelmus rufinasus, Cyrtobagous salviniae, Neohydronomus affinis, and Lysathia sp.) in South Africa. The plant species were grown in a two factorial design experiment, where atmospheric CO2 concentrations were set at ambient (400 ppm) or elevated (800 ppm), and plants were either subjected to or not subjected to herbivory by their target biological control agents. There was an overall increase in biomass production and C:N across all species at elevated CO2, both in the absence and presence of biological control, although C:N of M. aquaticum and biomass of A. filiculoides with herbivory were not constant with this trend. Insect feeding damage was reduced by elevated CO2, except for S. molesta. Thus, we can expect that plants will respond differently to CO2 increase, but the general trend suggests that these species will become more challenging to manage through biological control in future.
- Full Text:
- Date Issued: 2021
The effects of the composition and structure of quantum dots combined with cobalt phthalocyanine and an aptamer on the electrochemical detection of prostate specific antigen
- Nxele, Siphesihle R, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185002 , vital:44315 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109407"
- Description: The ability to functionalize and modify graphene-based quantum dots has also allowed for the tuning of their activity in different applications. A comparative study is carried out in this work where a prostate specific aptamer (PSA) and cobalt phthalocyanine molecule are combined with graphene quantum dots (GQDs), nitrogen doped graphene quantum dots (NGQDs) and graphitic carbon nitride quantum dots (gCNQDs) in order to determine the effects of quantum dots type (and therefore composition) on the electrocatalytic ability of the sensor to detect the analyte of interest. For the detection of prostate-specific antigen, electrochemical impedance spectroscopy (EIS) is employed to determine detection limits as well as sensitivity and selectivity of the aptasensors. Results showed a good performance of all sensors fabricated with the NGQDs based aptasensor showing the best performance with a detection limit of 1.54 pM in EIS as well as negligible interference in mixed samples. This electrode was further verified in spiked human serum samples and good recovery and low detection limits were determined, putting this aptasensor in good stead as a reliable, efficient PSA aptasensor.
- Full Text:
- Date Issued: 2021
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185002 , vital:44315 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109407"
- Description: The ability to functionalize and modify graphene-based quantum dots has also allowed for the tuning of their activity in different applications. A comparative study is carried out in this work where a prostate specific aptamer (PSA) and cobalt phthalocyanine molecule are combined with graphene quantum dots (GQDs), nitrogen doped graphene quantum dots (NGQDs) and graphitic carbon nitride quantum dots (gCNQDs) in order to determine the effects of quantum dots type (and therefore composition) on the electrocatalytic ability of the sensor to detect the analyte of interest. For the detection of prostate-specific antigen, electrochemical impedance spectroscopy (EIS) is employed to determine detection limits as well as sensitivity and selectivity of the aptasensors. Results showed a good performance of all sensors fabricated with the NGQDs based aptasensor showing the best performance with a detection limit of 1.54 pM in EIS as well as negligible interference in mixed samples. This electrode was further verified in spiked human serum samples and good recovery and low detection limits were determined, putting this aptasensor in good stead as a reliable, efficient PSA aptasensor.
- Full Text:
- Date Issued: 2021
The electrochemical detection of prostate specific antigen on glassy carbon electrode modified with combinations of graphene quantum dots, cobalt phthalocyanine and an aptamer
- Nxele, Siphesihle R, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185013 , vital:44316 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111462"
- Description: Herein, a novel aptasensor is developed for the electrochemical detection of prostate specific antigen (PSA) on electrode surfaces modified using various combinations of a Cobalt phthalocyanine (CoPc), an aptamer and graphene quantum dots (GQDs). Electrochemical impedance spectroscopy (EIS) as well as differential pulse voltammetry (DPV) are employed for the detection of PSA. In both analytical techniques, linear calibration curves were observed at a concentration range of 1.2–2.0 pM. The glassy carbon electrode where CoPc and GQDs are placed on the electrode when non-covalently linked followed by addition of the aptamer (GQDs-CoPc(ππ)-aptamer (sequential)) showed the best performance with a limit of detection (LoD) as low as 0.66 pM when using DPV. The detection limits were much lower than the dangerous levels reported for PSA in males tested for prostate cancer. This electrode showed selectivity for PSA in the presence of bovine serum albumin, glucose and L-cysteine. The aptasensor showed good stability, reproducibility and repeatability, deeming it a promising early detection device for prostate cancer.
- Full Text:
- Date Issued: 2021
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185013 , vital:44316 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111462"
- Description: Herein, a novel aptasensor is developed for the electrochemical detection of prostate specific antigen (PSA) on electrode surfaces modified using various combinations of a Cobalt phthalocyanine (CoPc), an aptamer and graphene quantum dots (GQDs). Electrochemical impedance spectroscopy (EIS) as well as differential pulse voltammetry (DPV) are employed for the detection of PSA. In both analytical techniques, linear calibration curves were observed at a concentration range of 1.2–2.0 pM. The glassy carbon electrode where CoPc and GQDs are placed on the electrode when non-covalently linked followed by addition of the aptamer (GQDs-CoPc(ππ)-aptamer (sequential)) showed the best performance with a limit of detection (LoD) as low as 0.66 pM when using DPV. The detection limits were much lower than the dangerous levels reported for PSA in males tested for prostate cancer. This electrode showed selectivity for PSA in the presence of bovine serum albumin, glucose and L-cysteine. The aptasensor showed good stability, reproducibility and repeatability, deeming it a promising early detection device for prostate cancer.
- Full Text:
- Date Issued: 2021
The hermeneutics of recovery
- Kong, Camillia, Campbell, Megan, Kpobi, Lily, Swartz, Leslie, Atuire, Caesar
- Authors: Kong, Camillia , Campbell, Megan , Kpobi, Lily , Swartz, Leslie , Atuire, Caesar
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302554 , vital:58207 , xlink:href="https://doi.org/10.1177/13634615211000549"
- Description: The widespread use of faith-based and traditional healing for mental disorders within African contexts is well known. However, normative responses tend to fall within two camps: on one hand, those oriented towards the biomedical model of psychiatry stress the abuses and superstition of such healing, whilst critics adopting a more ‘local’ perspective have fundamentally challenged the universalist claims of biomedical diagnostic categories and psychiatric treatments. What seemingly emerges is a dichotomy between those who endorse more ‘universalist’ or ‘relativist’ approaches as an analytical lens to the challenges of the diverse healing strands within African contexts. In this article, we draw upon the resources of philosophy and existing empirical work to challenge the notion that constructive dialogue cannot be had between seemingly incommensurable healing practices in global mental health. First, we suggest the need for much-needed conceptual clarity to explore the hermeneutics of meaning, practice, and understanding, in order to forge constructive normative pathways of dialogue between seemingly incommensurable values and conceptual schemas around mental disorder and healing. Second, we contextualise the complex motives to emphasise difference amongst health practitioners within a competitive healing economy. Finally, we appeal to the notion of recovery as discovery as a fruitful conceptual framework which incorporates dialogue, comparative evaluation, and cross-cultural enrichment across divergent conceptualisations of mental health.
- Full Text:
- Date Issued: 2021
- Authors: Kong, Camillia , Campbell, Megan , Kpobi, Lily , Swartz, Leslie , Atuire, Caesar
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302554 , vital:58207 , xlink:href="https://doi.org/10.1177/13634615211000549"
- Description: The widespread use of faith-based and traditional healing for mental disorders within African contexts is well known. However, normative responses tend to fall within two camps: on one hand, those oriented towards the biomedical model of psychiatry stress the abuses and superstition of such healing, whilst critics adopting a more ‘local’ perspective have fundamentally challenged the universalist claims of biomedical diagnostic categories and psychiatric treatments. What seemingly emerges is a dichotomy between those who endorse more ‘universalist’ or ‘relativist’ approaches as an analytical lens to the challenges of the diverse healing strands within African contexts. In this article, we draw upon the resources of philosophy and existing empirical work to challenge the notion that constructive dialogue cannot be had between seemingly incommensurable healing practices in global mental health. First, we suggest the need for much-needed conceptual clarity to explore the hermeneutics of meaning, practice, and understanding, in order to forge constructive normative pathways of dialogue between seemingly incommensurable values and conceptual schemas around mental disorder and healing. Second, we contextualise the complex motives to emphasise difference amongst health practitioners within a competitive healing economy. Finally, we appeal to the notion of recovery as discovery as a fruitful conceptual framework which incorporates dialogue, comparative evaluation, and cross-cultural enrichment across divergent conceptualisations of mental health.
- Full Text:
- Date Issued: 2021
The improved antibacterial efficiency of a zinc phthalocyanine when embedded on silver nanoparticle modified silica nanofibers
- Mapukata, Sivuyisiwe, Britton, Jonathan, Osifeko, Olawale L, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Britton, Jonathan , Osifeko, Olawale L , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185784 , vital:44423 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.102100"
- Description: This work reports on the fabrication and modification of electrospun polymer free silica nanofibers (SiO2 NFs) with the aim of creating heterogeneous antibacterial catalysts. The optical and photophysical properties of the obtained NFs i.e. bare SiO2, Ag-SiO2, Pc-SiO2 and Pc@Ag-SiO2 NFs (Pc = phthalocyanine) were compared and reported. The singlet oxygen quantum yields of the Pc-SiO2 and Pc@Ag-SiO2 NFs were also quantified and found to be 0.08 and 0.12, respectively, in water. All the modified SiO2 NFs were found to possess photoactivity against S. aureus with the most effective being the Pc@Ag-SiO2 NFs due to the synergy between the Pc and Ag nanoparticles. The bare SiO2 NFs do not exhibit any antibacterial activity while the Ag-SiO2 and Pc@Ag-SiO2 NFs were found to also exhibit dark toxicity. The generated photocatalysts are attractive because they are active against bacteria and they are easily retrievable post-application. The nanocatalysts reported herein are therefore feasible candidates for real-life antibacterial applications.
- Full Text:
- Date Issued: 2021
- Authors: Mapukata, Sivuyisiwe , Britton, Jonathan , Osifeko, Olawale L , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185784 , vital:44423 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.102100"
- Description: This work reports on the fabrication and modification of electrospun polymer free silica nanofibers (SiO2 NFs) with the aim of creating heterogeneous antibacterial catalysts. The optical and photophysical properties of the obtained NFs i.e. bare SiO2, Ag-SiO2, Pc-SiO2 and Pc@Ag-SiO2 NFs (Pc = phthalocyanine) were compared and reported. The singlet oxygen quantum yields of the Pc-SiO2 and Pc@Ag-SiO2 NFs were also quantified and found to be 0.08 and 0.12, respectively, in water. All the modified SiO2 NFs were found to possess photoactivity against S. aureus with the most effective being the Pc@Ag-SiO2 NFs due to the synergy between the Pc and Ag nanoparticles. The bare SiO2 NFs do not exhibit any antibacterial activity while the Ag-SiO2 and Pc@Ag-SiO2 NFs were found to also exhibit dark toxicity. The generated photocatalysts are attractive because they are active against bacteria and they are easily retrievable post-application. The nanocatalysts reported herein are therefore feasible candidates for real-life antibacterial applications.
- Full Text:
- Date Issued: 2021
The influence of biophysical and socio-economic factors on the effectiveness of private land conservation areas in preventing natural land cover loss across South Africa
- Shumba, Tafadzwa, de Vos, Alta, Biggs, Reinette, Esler, Karen J, Clements, Hayley S
- Authors: Shumba, Tafadzwa , de Vos, Alta , Biggs, Reinette , Esler, Karen J , Clements, Hayley S
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415940 , vital:71302 , xlink:href="https://doi.org/10.1016/j.gecco.2021.e01670"
- Description: There is increasing interest in the potential of private land conservation areas (PLCAs) as a complementary biodiversity conservation strategy to state-owned protected areas. However, there is limited understanding of how the diverse social-ecological contexts of PLCAs influence their effectiveness in conserving biodiversity. Here, we investigated how the effectiveness of South African PLCAs in conserving biodiversity varied across social-ecological contexts, using natural land cover as a proxy. Social-ecological contexts were represented by biophysical and legal factors (distance to towns and roads, elevation, slope, terrain ruggedness, rainfall, PLCA size, distance to state-owned national parks, and presence of legal protection) and, for a subset of commercially-operated PLCAs, management factors (adopted business model, and profitability).
- Full Text:
- Date Issued: 2021
- Authors: Shumba, Tafadzwa , de Vos, Alta , Biggs, Reinette , Esler, Karen J , Clements, Hayley S
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415940 , vital:71302 , xlink:href="https://doi.org/10.1016/j.gecco.2021.e01670"
- Description: There is increasing interest in the potential of private land conservation areas (PLCAs) as a complementary biodiversity conservation strategy to state-owned protected areas. However, there is limited understanding of how the diverse social-ecological contexts of PLCAs influence their effectiveness in conserving biodiversity. Here, we investigated how the effectiveness of South African PLCAs in conserving biodiversity varied across social-ecological contexts, using natural land cover as a proxy. Social-ecological contexts were represented by biophysical and legal factors (distance to towns and roads, elevation, slope, terrain ruggedness, rainfall, PLCA size, distance to state-owned national parks, and presence of legal protection) and, for a subset of commercially-operated PLCAs, management factors (adopted business model, and profitability).
- Full Text:
- Date Issued: 2021
The influence of citrus orchard age on the ecology of entomopathogenic fungi and nematodes
- Albertyn, Sonnica, Moore, Sean D, Marsberg, Tamryn, Coombes, Candice A, Hill, Martin P
- Authors: Albertyn, Sonnica , Moore, Sean D , Marsberg, Tamryn , Coombes, Candice A , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417790 , vital:71486 , xlink:href="https://doi.org/10.1080/09583157.2020.1830949"
- Description: A three-year survey of the ecology of entomopathogenic nematodes (EPN) and entomopathogenic fungi (EPF) was undertaken on soils from citrus orchards of different ages to determine the influence of orchard age on the ecology of entomopathogenic fungi and nematodes. The influence of mulch and irrigation method on the occurrence of EPN and EPF was also determined. Most of the isolates recovered (n = 810) were Beauveria sp. (87.88% of all isolates), followed by Metarhizium sp. (11.87% of all isolates). Only 0.24% of soil samples collected during this study tested positive for EPN. All EPN isolates recovered were Heterorhabditis bacteriophora. No significant differences in EPF occurrence were recorded between orchards under drip and micro-sprinkler irrigation. EPF occurrence was significantly lower (P = 0.016) in orchards covered by mulch (31.85% ± 2.07% occurrence) than in orchards with no covering (38.57% ± 1.57% occurrence). EPF occurrence of 40.33 ± 2.13% was highest in non-bearing orchards, followed by mature orchards (nine years or older) (36.76 ± 2.05% of samples) with the lowest EPF occurrence of 25.30 ± 2.02% reported in juvenile orchards (four to eight years old). Juvenile orchards sustain significantly less EPF than mature and non-bearing orchards because of the combined negative impact of less favourable environmental conditions (lower shade density) and fungicide applications.
- Full Text:
- Date Issued: 2021
- Authors: Albertyn, Sonnica , Moore, Sean D , Marsberg, Tamryn , Coombes, Candice A , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417790 , vital:71486 , xlink:href="https://doi.org/10.1080/09583157.2020.1830949"
- Description: A three-year survey of the ecology of entomopathogenic nematodes (EPN) and entomopathogenic fungi (EPF) was undertaken on soils from citrus orchards of different ages to determine the influence of orchard age on the ecology of entomopathogenic fungi and nematodes. The influence of mulch and irrigation method on the occurrence of EPN and EPF was also determined. Most of the isolates recovered (n = 810) were Beauveria sp. (87.88% of all isolates), followed by Metarhizium sp. (11.87% of all isolates). Only 0.24% of soil samples collected during this study tested positive for EPN. All EPN isolates recovered were Heterorhabditis bacteriophora. No significant differences in EPF occurrence were recorded between orchards under drip and micro-sprinkler irrigation. EPF occurrence was significantly lower (P = 0.016) in orchards covered by mulch (31.85% ± 2.07% occurrence) than in orchards with no covering (38.57% ± 1.57% occurrence). EPF occurrence of 40.33 ± 2.13% was highest in non-bearing orchards, followed by mature orchards (nine years or older) (36.76 ± 2.05% of samples) with the lowest EPF occurrence of 25.30 ± 2.02% reported in juvenile orchards (four to eight years old). Juvenile orchards sustain significantly less EPF than mature and non-bearing orchards because of the combined negative impact of less favourable environmental conditions (lower shade density) and fungicide applications.
- Full Text:
- Date Issued: 2021
The photodynamic activities of the gold nanoparticle conjugates of phosphorus (V) and gallium (III) A3 meso-triarylcorroles
- Soy, Rodah C, Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Soy, Rodah C , Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185678 , vital:44409 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109631"
- Description: The synthesis and characterization of series of P(V) and Ga(III) A3 triarylcorrole complexes with 4-methylthiophenyl (2a, 3a), thien-3-yl (2b, 3b) and thien-2-yl (2c, 3c) meso-groups are reported along with the physicochemical and photodynamic activity properties of the dyes and their gold nanoparticle (AuNP) conjugates. The Ga(III) corrole series have lower fluorescence quantum yields and higher singlet oxygen quantum yields than the analogous P(V) complexes. Upon conjugation to AuNPs, the fluorescence quantum yields of the P(V) and Ga(III) corroles decrease, while the singlet oxygen quantum yields increase due to an external heavy atom effect. The P(V) and Ga(III) corroles exhibit relatively low in vitro dark cytotoxicity, which was further enhanced upon conjugation to AuNPs. The P(V) complexes and their AuNP conjugates display more favorable PDT activity properties upon illumination with a Thorlabs 625 nm light-emitting diode (288 J cm−2) with phototoxicity indices > 18.5 and 20.8, respectively, for the meso-thienyl-substituted 2b-AuNP and 2c-AuNP conjugates. Optical spectroscopy analyses demonstrate that this can be attributed to there being significantly less aggregation due to the presence of two trans-hydroxy axial ligands.
- Full Text:
- Date Issued: 2021
- Authors: Soy, Rodah C , Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185678 , vital:44409 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109631"
- Description: The synthesis and characterization of series of P(V) and Ga(III) A3 triarylcorrole complexes with 4-methylthiophenyl (2a, 3a), thien-3-yl (2b, 3b) and thien-2-yl (2c, 3c) meso-groups are reported along with the physicochemical and photodynamic activity properties of the dyes and their gold nanoparticle (AuNP) conjugates. The Ga(III) corrole series have lower fluorescence quantum yields and higher singlet oxygen quantum yields than the analogous P(V) complexes. Upon conjugation to AuNPs, the fluorescence quantum yields of the P(V) and Ga(III) corroles decrease, while the singlet oxygen quantum yields increase due to an external heavy atom effect. The P(V) and Ga(III) corroles exhibit relatively low in vitro dark cytotoxicity, which was further enhanced upon conjugation to AuNPs. The P(V) complexes and their AuNP conjugates display more favorable PDT activity properties upon illumination with a Thorlabs 625 nm light-emitting diode (288 J cm−2) with phototoxicity indices > 18.5 and 20.8, respectively, for the meso-thienyl-substituted 2b-AuNP and 2c-AuNP conjugates. Optical spectroscopy analyses demonstrate that this can be attributed to there being significantly less aggregation due to the presence of two trans-hydroxy axial ligands.
- Full Text:
- Date Issued: 2021
The photodynamic activities of the gold nanoparticle conjugates of phosphorus (V) and gallium (III) A3 meso-triarylcorroles
- Soy, Rodah C, Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Soy, Rodah C , Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184978 , vital:44313 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109631"
- Description: The synthesis and characterization of series of P(V) and Ga(III) A3 triarylcorrole complexes with 4-methylthiophenyl (2a, 3a), thien-3-yl (2b, 3b) and thien-2-yl (2c, 3c) meso-groups are reported along with the physicochemical and photodynamic activity properties of the dyes and their gold nanoparticle (AuNP) conjugates. The Ga(III) corrole series have lower fluorescence quantum yields and higher singlet oxygen quantum yields than the analogous P(V) complexes. Upon conjugation to AuNPs, the fluorescence quantum yields of the P(V) and Ga(III) corroles decrease, while the singlet oxygen quantum yields increase due to an external heavy atom effect. The P(V) and Ga(III) corroles exhibit relatively low in vitro dark cytotoxicity, which was further enhanced upon conjugation to AuNPs. The P(V) complexes and their AuNP conjugates display more favorable PDT activity properties upon illumination with a Thorlabs 625 nm light-emitting diode (288 J cm−2) with phototoxicity indices > 18.5 and 20.8, respectively, for the meso-thienyl-substituted 2b-AuNP and 2c-AuNP conjugates. Optical spectroscopy analyses demonstrate that this can be attributed to there being significantly less aggregation due to the presence of two trans-hydroxy axial ligands.
- Full Text:
- Date Issued: 2021
- Authors: Soy, Rodah C , Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184978 , vital:44313 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109631"
- Description: The synthesis and characterization of series of P(V) and Ga(III) A3 triarylcorrole complexes with 4-methylthiophenyl (2a, 3a), thien-3-yl (2b, 3b) and thien-2-yl (2c, 3c) meso-groups are reported along with the physicochemical and photodynamic activity properties of the dyes and their gold nanoparticle (AuNP) conjugates. The Ga(III) corrole series have lower fluorescence quantum yields and higher singlet oxygen quantum yields than the analogous P(V) complexes. Upon conjugation to AuNPs, the fluorescence quantum yields of the P(V) and Ga(III) corroles decrease, while the singlet oxygen quantum yields increase due to an external heavy atom effect. The P(V) and Ga(III) corroles exhibit relatively low in vitro dark cytotoxicity, which was further enhanced upon conjugation to AuNPs. The P(V) complexes and their AuNP conjugates display more favorable PDT activity properties upon illumination with a Thorlabs 625 nm light-emitting diode (288 J cm−2) with phototoxicity indices > 18.5 and 20.8, respectively, for the meso-thienyl-substituted 2b-AuNP and 2c-AuNP conjugates. Optical spectroscopy analyses demonstrate that this can be attributed to there being significantly less aggregation due to the presence of two trans-hydroxy axial ligands.
- Full Text:
- Date Issued: 2021