Analytical Detection and Electrocatalysis of Paracetamol in Aqueous Media Using Rare‐Earth Double‐Decker Phthalocyaninato Chelates as Electrochemically Active Materials
- Sekhosana, Kutloana E, Nkhahle, Reitumetse, Nyokong, Tebello
- Authors: Sekhosana, Kutloana E , Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190840 , vital:45033 , xlink:href="https://doi.org/10.1002/slct.202002268"
- Description: Paracetamol (PA), being an analgesic and antipyretic medicine, can cause fatal hepatotoxicity and nephrotoxicity when overdosed. It is therefore important to develop electrochemical sensors that can monitor and quantify it in aquatic environments. In this study, rare-earth sandwich-type phthalocyaninato chelates based on neodymium (1 a) and samarium (1 b) were employed as electrocatalysts to modify glassy carbon electrodes (GCE) for the first time. It was found that 1 a-modified GCE (herein referred to as 1 a-GCE) is less conductive than 1 b-modified counterpart (1 b-GCE). A larger rate constant was also obtained for 1 b-GCE. It was established that a faster oxidation rate efficiency was responsible for lower limit of detection value obtained for 1 b-GCE as compared to 1 a-GCE.
- Full Text:
- Date Issued: 2020
- Authors: Sekhosana, Kutloana E , Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190840 , vital:45033 , xlink:href="https://doi.org/10.1002/slct.202002268"
- Description: Paracetamol (PA), being an analgesic and antipyretic medicine, can cause fatal hepatotoxicity and nephrotoxicity when overdosed. It is therefore important to develop electrochemical sensors that can monitor and quantify it in aquatic environments. In this study, rare-earth sandwich-type phthalocyaninato chelates based on neodymium (1 a) and samarium (1 b) were employed as electrocatalysts to modify glassy carbon electrodes (GCE) for the first time. It was found that 1 a-modified GCE (herein referred to as 1 a-GCE) is less conductive than 1 b-modified counterpart (1 b-GCE). A larger rate constant was also obtained for 1 b-GCE. It was established that a faster oxidation rate efficiency was responsible for lower limit of detection value obtained for 1 b-GCE as compared to 1 a-GCE.
- Full Text:
- Date Issued: 2020
Double-and quintuple-decker phthalocyaninato chelates as optical limiters in solution and thin film
- Sekhosana, Kutloano E, Nyokong, Tebello
- Authors: Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186733 , vital:44529 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107836"
- Description: The rare-earth quintuple-decker phthalocyaninato chelates (3a and 3b) were synthesized from their parent rare-earth double-decker phthalocyaninato precursors (2b and 2a). After extensive structural elucidation, these complexes were subjected to various spectroscopic techniques to investigate their electronic behavior. It was found that complexes 3a and 3b existed as the oxidized forms. When investigating the optical limiting properties, all these complexes were found to exhibit reverse saturable absorption, with complex 2a showing a more enhanced open-aperture Z-Scan signature than complex 2b. Interestingly, complexes 3a and 3b (in solution) exhibited better open-aperture Z-Scan signatures than their parent rare-earth double-decker phthalocyaninato precursors (2b and 2a). However, thin films fabricated from these complexes did not show an improvement in the optical limiting properties when compared to 2a, 3a, 3b except for that which was prepared from 2b. This study shows the importance of extensive π-electron system in phthalocyaninato complexes for optical limiting applications.
- Full Text:
- Date Issued: 2020
- Authors: Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186733 , vital:44529 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.107836"
- Description: The rare-earth quintuple-decker phthalocyaninato chelates (3a and 3b) were synthesized from their parent rare-earth double-decker phthalocyaninato precursors (2b and 2a). After extensive structural elucidation, these complexes were subjected to various spectroscopic techniques to investigate their electronic behavior. It was found that complexes 3a and 3b existed as the oxidized forms. When investigating the optical limiting properties, all these complexes were found to exhibit reverse saturable absorption, with complex 2a showing a more enhanced open-aperture Z-Scan signature than complex 2b. Interestingly, complexes 3a and 3b (in solution) exhibited better open-aperture Z-Scan signatures than their parent rare-earth double-decker phthalocyaninato precursors (2b and 2a). However, thin films fabricated from these complexes did not show an improvement in the optical limiting properties when compared to 2a, 3a, 3b except for that which was prepared from 2b. This study shows the importance of extensive π-electron system in phthalocyaninato complexes for optical limiting applications.
- Full Text:
- Date Issued: 2020
Synthesis of novel Schiff base cobalt (II) and iron (iii) complexes as cathode catalysts for microbial fuel cell applications
- Sen, Pinar, Akagunduz, Dilan, Aghdam, Araz S, Cebeci, Fevzi C, Nyokong, Tebello, Catal, Tunc
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz S , Cebeci, Fevzi C , Nyokong, Tebello , Catal, Tunc
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190861 , vital:45035 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Date Issued: 2020
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz S , Cebeci, Fevzi C , Nyokong, Tebello , Catal, Tunc
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190861 , vital:45035 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Date Issued: 2020
Synthesis of novel Schiff base cobalt (II) and iron (iii) complexes as cathode catalysts for microbial fuel cell applications
- Sen, Pinar, Akagunduz, Dilan, Aghdam, Araz Sheibani, Cebeci, Fevzi C, Nyokong, Tebello
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz Sheibani , Cebeci, Fevzi C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187015 , vital:44556 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Date Issued: 2020
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz Sheibani , Cebeci, Fevzi C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187015 , vital:44556 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Date Issued: 2020
New difluoroboron complexes based on N, O-chelated Schiff base ligands: Synthesis, characterization, DFT calculations and photophysical and electrochemical properties
- Sen, Pinar, Mpeta, Lekhetho S, Mack, John, Nyokong, Tebello
- Authors: Sen, Pinar , Mpeta, Lekhetho S , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186207 , vital:44473 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117262"
- Description: The synthesis of new Schiff bases and their dinuclear boron complexes is described, along with their characterization by 1H and 13C NMR, FT-IR, and UV–visible absorption spectroscopy, mass spectrometry, and EDX for elemental analysis. The optical and photophysical properties were examined in terms of their absorption and emission behavior, fluorescence quantum yields and fluorescence lifetimes. The flexible dinuclear boron complexes that are linked by a flexible carbon chain exhibited large Stokes shifts in the range from 92 nm to 115 nm in contrast to BODIPY dyes. Those properties make these complexes precious for applications in fluorescence materials. And also theoretical calculations were obtained by using Density Functional Theory (DFT) methods.
- Full Text:
- Date Issued: 2020
- Authors: Sen, Pinar , Mpeta, Lekhetho S , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186207 , vital:44473 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117262"
- Description: The synthesis of new Schiff bases and their dinuclear boron complexes is described, along with their characterization by 1H and 13C NMR, FT-IR, and UV–visible absorption spectroscopy, mass spectrometry, and EDX for elemental analysis. The optical and photophysical properties were examined in terms of their absorption and emission behavior, fluorescence quantum yields and fluorescence lifetimes. The flexible dinuclear boron complexes that are linked by a flexible carbon chain exhibited large Stokes shifts in the range from 92 nm to 115 nm in contrast to BODIPY dyes. Those properties make these complexes precious for applications in fluorescence materials. And also theoretical calculations were obtained by using Density Functional Theory (DFT) methods.
- Full Text:
- Date Issued: 2020
Detection and effects of selected pharmaceutical compounds from selected water bodies in the Eastern Cape Province, South Africa
- Authors: Setshedi, Koketso Josinah
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177074 , vital:42788
- Description: Theses embargoed. Release date March 2023. , Thesis (MSc) -- Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Setshedi, Koketso Josinah
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177074 , vital:42788
- Description: Theses embargoed. Release date March 2023. , Thesis (MSc) -- Faculty of Pharmacy, Department of Pharmaceutical Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
Photodynamic antimicrobial chemotherapy of asymmetric porphyrin-silver conjugates towards photoinactivation of Staphylococcus aureus
- Shabangu, Samuel M, Babu, Balaji, Soy, Rodah C, Managa, Muthumuni, Sekhosana, Kutloano E, Nyokong, Tebello
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Managa, Muthumuni , Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186536 , vital:44509 , xlink:href="https://doi.org/10.1080/00958972.2020.1739273"
- Description: Asymmetric mono-carboxy-porphyrins, (5-(4-carboxyphenyl)10,15, 20-tris(pentafluorophenyl)porphyrinato zinc(II) (1), 5-(4- carboxyphenyl)10,15,20-triphenylporphyrinato zinc(II) (2) and 5-(4- carboxyphenyl)10,15,20-tris(2-thienyl)porphyrinato zinc(II) (3), were linked to Ag nanoparticles (AgNPs) through amide bonds and selfassembly (the latter only for 3). The porphyrins and conjugates were used for photodynamic antimicrobial chemotherapy (PACT) against Staphylococcus aureus. PACT uses singlet oxygen for antimicrobial activity. Complex 3 and its conjugates had higher singlet oxygen quantum yields and higher log reduction when compared with the rest of the porphyrins and corresponding conjugates. These high log reductions for 3 and its conjugate were attributed to the presence of sulfur groups whereby there was more interaction with the bacterial membrane.
- Full Text:
- Date Issued: 2020
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Managa, Muthumuni , Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186536 , vital:44509 , xlink:href="https://doi.org/10.1080/00958972.2020.1739273"
- Description: Asymmetric mono-carboxy-porphyrins, (5-(4-carboxyphenyl)10,15, 20-tris(pentafluorophenyl)porphyrinato zinc(II) (1), 5-(4- carboxyphenyl)10,15,20-triphenylporphyrinato zinc(II) (2) and 5-(4- carboxyphenyl)10,15,20-tris(2-thienyl)porphyrinato zinc(II) (3), were linked to Ag nanoparticles (AgNPs) through amide bonds and selfassembly (the latter only for 3). The porphyrins and conjugates were used for photodynamic antimicrobial chemotherapy (PACT) against Staphylococcus aureus. PACT uses singlet oxygen for antimicrobial activity. Complex 3 and its conjugates had higher singlet oxygen quantum yields and higher log reduction when compared with the rest of the porphyrins and corresponding conjugates. These high log reductions for 3 and its conjugate were attributed to the presence of sulfur groups whereby there was more interaction with the bacterial membrane.
- Full Text:
- Date Issued: 2020
Susceptibility of Staphylococcus aureus to porphyrin-silver nanoparticle mediated photodynamic antimicrobial chemotherapy
- Shabangu, Samuel M, Babu, Balaji, Soy, Rodah C, Ovim, James, Amuhaya, Edith, Nyokong, Tebello
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Ovim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186262 , vital:44479 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117158"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is employed against multi drug resistant Staphylococcus aureus using porphyrins combined with silver nanoparticles to bring about a combined photodynamic effect. We employ Zn-meso-5,10,15,20-tetra(4-pyridyl) (1), Zn-meso-5,10,15,20-tetrathienyl (2), and Zn-meso-5-(4- hydroxyphenyl)- 10,15,20-tris(2-thienyl)(3) porphyrins and their self-assembled conjugates with silver nanoparticles for PACT against Staphylococcus aureus. Complex 3 with nanoparticles was found to perform better resulting in 0% bacterial viability at 60 min.
- Full Text:
- Date Issued: 2020
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Ovim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186262 , vital:44479 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117158"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is employed against multi drug resistant Staphylococcus aureus using porphyrins combined with silver nanoparticles to bring about a combined photodynamic effect. We employ Zn-meso-5,10,15,20-tetra(4-pyridyl) (1), Zn-meso-5,10,15,20-tetrathienyl (2), and Zn-meso-5-(4- hydroxyphenyl)- 10,15,20-tris(2-thienyl)(3) porphyrins and their self-assembled conjugates with silver nanoparticles for PACT against Staphylococcus aureus. Complex 3 with nanoparticles was found to perform better resulting in 0% bacterial viability at 60 min.
- Full Text:
- Date Issued: 2020
Socioeconomic and geographic variations in antenatal care coverage in Angola: further analysis of the 2015 demographic and health survey
- Shibre, Gebretsadik, Zegeye, Betregiorgis, Idriss-Wheeler, Dina, Ahinkorah, Bright Opoku, Oladimeji, Olanrewaju, Yaya, Sanni
- Authors: Shibre, Gebretsadik , Zegeye, Betregiorgis , Idriss-Wheeler, Dina , Ahinkorah, Bright Opoku , Oladimeji, Olanrewaju , Yaya, Sanni
- Date: 2023
- Subjects: Prenatal care , Mothers -- Mortality , Health surveys
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4489 , vital:44125 , https://doi.org/10.1186/s12889-020-09320-1
- Description: In African countries, including Angola, antenatal care (ANC) coverage is suboptimal and maternal mortality is still high due to pregnancy and childbirth-related complications. There is evidence of disparities in the uptake of ANC services, however, little is known about both the socio-economic and geographic-based disparity in the use of ANC services in Angola. The aim of this study was to assess the extent of socio-economic, urban-rural and subnational inequality in ANC coverage in Angola. We analyzed data from the 2015 Angola Demographic and Health Survey (ADHS) using the World Health Organization (WHO) Health Equity Assessment Toolkit (HEAT) software. The analysis consisted of disaggregated ANC coverage rates using four equity stratifiers (economic status, education, residence, and region) and four summary measures (Difference, Population Attributable Risk, Ratio and Population Attributable Fraction). To measure statistical significance, an uncertainty interval (UI) of 95% was constructed around point estimates. The study showed both absolute and relative inequalities in coverage of ANC services in Angola. More specifically, inequality favored women who were rich (D = 54.2, 95% UI; 49.59, 58.70, PAF = 43.5, 95% UI; 40.12, 46.92), educated (PAR = 19.9, 95% UI; 18.14, 21.64, R = 2.14, 95% UI; 1.96, 2.32), living in regions such as Luanda (D = 51.7, 95% UI; 43.56, 59.85, R = 2.64, 95% UI; 2.01, 3.26) and residing in urban dwellings (PAF = 20, 95% UI; 17.70, 22.38, PAR = 12.3, 95% UI; 10.88, 13.75). The uptake of ANC services were lower among poor, uneducated, and rural residents as well as women from the Cuanza Sul region. Government policy makers must consider vulnerable subpopulations when designing needed interventions to improve ANC coverage in Angola to achieve the 2030 Sustainable Development Goal of reducing global maternal mortality ratio to 70 deaths per 100,000 live births.
- Full Text:
- Date Issued: 2023
- Authors: Shibre, Gebretsadik , Zegeye, Betregiorgis , Idriss-Wheeler, Dina , Ahinkorah, Bright Opoku , Oladimeji, Olanrewaju , Yaya, Sanni
- Date: 2023
- Subjects: Prenatal care , Mothers -- Mortality , Health surveys
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4489 , vital:44125 , https://doi.org/10.1186/s12889-020-09320-1
- Description: In African countries, including Angola, antenatal care (ANC) coverage is suboptimal and maternal mortality is still high due to pregnancy and childbirth-related complications. There is evidence of disparities in the uptake of ANC services, however, little is known about both the socio-economic and geographic-based disparity in the use of ANC services in Angola. The aim of this study was to assess the extent of socio-economic, urban-rural and subnational inequality in ANC coverage in Angola. We analyzed data from the 2015 Angola Demographic and Health Survey (ADHS) using the World Health Organization (WHO) Health Equity Assessment Toolkit (HEAT) software. The analysis consisted of disaggregated ANC coverage rates using four equity stratifiers (economic status, education, residence, and region) and four summary measures (Difference, Population Attributable Risk, Ratio and Population Attributable Fraction). To measure statistical significance, an uncertainty interval (UI) of 95% was constructed around point estimates. The study showed both absolute and relative inequalities in coverage of ANC services in Angola. More specifically, inequality favored women who were rich (D = 54.2, 95% UI; 49.59, 58.70, PAF = 43.5, 95% UI; 40.12, 46.92), educated (PAR = 19.9, 95% UI; 18.14, 21.64, R = 2.14, 95% UI; 1.96, 2.32), living in regions such as Luanda (D = 51.7, 95% UI; 43.56, 59.85, R = 2.64, 95% UI; 2.01, 3.26) and residing in urban dwellings (PAF = 20, 95% UI; 17.70, 22.38, PAR = 12.3, 95% UI; 10.88, 13.75). The uptake of ANC services were lower among poor, uneducated, and rural residents as well as women from the Cuanza Sul region. Government policy makers must consider vulnerable subpopulations when designing needed interventions to improve ANC coverage in Angola to achieve the 2030 Sustainable Development Goal of reducing global maternal mortality ratio to 70 deaths per 100,000 live births.
- Full Text:
- Date Issued: 2023
Effectiveness of private land conservation areas in maintaining natural land cover and biodiversity intactness
- Shumba, Tafadzwa, de Vos, Alta, Biggs, Reinette, Esler, Karen J, Ament, Judith M, Clements, Hayley S
- Authors: Shumba, Tafadzwa , de Vos, Alta , Biggs, Reinette , Esler, Karen J , Ament, Judith M , Clements, Hayley S
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415852 , vital:71294 , xlink:href="https://doi.org/10.1016/j.gecco.2020.e00935"
- Description: Private land conservation areas (PLCAs) are increasingly looked to for meeting the deficit left by state-owned protected areas in reaching global conservation targets. However, despite the increasing extent and recognition of PLCAs as a complementary conservation strategy, little research has been done to quantify their effectiveness; a critical consideration if they are to be counted towards international biodiversity conservation targets. The long history of PLCAs in South Africa provides an interesting case study to address this knowledge gap. Here, we quantified the effectiveness of South African PLCAs by comparing losses in natural land cover and biodiversity intactness within PLCAs with different levels of protection to that of unprotected control points. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in natural land cover and biodiversity intactness would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. Consequences of natural land cover loss on biodiversity intactness were thus assessed, thus advancing standard approaches for quantifying effectiveness.
- Full Text:
- Date Issued: 2020
- Authors: Shumba, Tafadzwa , de Vos, Alta , Biggs, Reinette , Esler, Karen J , Ament, Judith M , Clements, Hayley S
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415852 , vital:71294 , xlink:href="https://doi.org/10.1016/j.gecco.2020.e00935"
- Description: Private land conservation areas (PLCAs) are increasingly looked to for meeting the deficit left by state-owned protected areas in reaching global conservation targets. However, despite the increasing extent and recognition of PLCAs as a complementary conservation strategy, little research has been done to quantify their effectiveness; a critical consideration if they are to be counted towards international biodiversity conservation targets. The long history of PLCAs in South Africa provides an interesting case study to address this knowledge gap. Here, we quantified the effectiveness of South African PLCAs by comparing losses in natural land cover and biodiversity intactness within PLCAs with different levels of protection to that of unprotected control points. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in natural land cover and biodiversity intactness would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. Consequences of natural land cover loss on biodiversity intactness were thus assessed, thus advancing standard approaches for quantifying effectiveness.
- Full Text:
- Date Issued: 2020
Investigating cell culture models for improved understanding of adipose tissue and co-morbidities in vitro
- Authors: Stoffels, Mihlali
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164674 , vital:41154
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
- Full Text:
- Date Issued: 2020
- Authors: Stoffels, Mihlali
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164674 , vital:41154
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
- Full Text:
- Date Issued: 2020
Oral Phytothymol ameliorates the stress induced IBS symptoms
- Subramaniyam, Selvaraj, Yang, Shuyou, Diallo, Bakary N, Fanshu, Xu, Lei, Luo, Li, Chong, Tastan-Bishop, Özlem, Bhattacharyya, Sanjib
- Authors: Subramaniyam, Selvaraj , Yang, Shuyou , Diallo, Bakary N , Fanshu, Xu , Lei, Luo , Li, Chong , Tastan-Bishop, Özlem , Bhattacharyya, Sanjib
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426034 , vital:72308 , xlink:href="https://doi.org/10.1038/s41598-020-70420-4"
- Description: Physical stressors play a crucial role in the progression of irritable bowel syndrome (IBS). Here we report a heterogeneous physical stress induced IBS rat model which shows depression and subsequent modulation of IBS by oral treatment of thymol. Oral administration of Thymol reduces the stress induced IBS significantly altering the stress induced gastrointestinal hypermotility, prolonged the whole gut transit time, and increased abdominal withdrawal reflex suggesting gastrointestinal hypermotility and visceral discomfort caused the onset of depression. Immunohistochemical analysis in small intestine and colon of rats shows the decreased 5-HT3AR expression level while thymol treatment normalized the 5-HT3AR expression in the stressed rats. Molecular docking studies showed that thymol competes with endogenous serotonin and an antagonist, Tropisetron and all have similar binding energies to 5-HT3AR. Molecular dynamics simulations revealed that thymol and tropisetron might have similar effects on 5-HT3AR. Our study suggest that thymol improves IBS symptoms through 5-HT3AR, could be useful for the treatment of IBS.
- Full Text:
- Date Issued: 2020
- Authors: Subramaniyam, Selvaraj , Yang, Shuyou , Diallo, Bakary N , Fanshu, Xu , Lei, Luo , Li, Chong , Tastan-Bishop, Özlem , Bhattacharyya, Sanjib
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426034 , vital:72308 , xlink:href="https://doi.org/10.1038/s41598-020-70420-4"
- Description: Physical stressors play a crucial role in the progression of irritable bowel syndrome (IBS). Here we report a heterogeneous physical stress induced IBS rat model which shows depression and subsequent modulation of IBS by oral treatment of thymol. Oral administration of Thymol reduces the stress induced IBS significantly altering the stress induced gastrointestinal hypermotility, prolonged the whole gut transit time, and increased abdominal withdrawal reflex suggesting gastrointestinal hypermotility and visceral discomfort caused the onset of depression. Immunohistochemical analysis in small intestine and colon of rats shows the decreased 5-HT3AR expression level while thymol treatment normalized the 5-HT3AR expression in the stressed rats. Molecular docking studies showed that thymol competes with endogenous serotonin and an antagonist, Tropisetron and all have similar binding energies to 5-HT3AR. Molecular dynamics simulations revealed that thymol and tropisetron might have similar effects on 5-HT3AR. Our study suggest that thymol improves IBS symptoms through 5-HT3AR, could be useful for the treatment of IBS.
- Full Text:
- Date Issued: 2020
Ethics and education as practices of freedom
- Authors: Tabensky, Pedro
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305672 , vital:58602 , xlink:href="https://doi.org/10.1080/00131857.2020.1791822"
- Description: On the one hand, according to Richard Rorty, Paulo Freire and others, education is the practice of freedom. On the other hand, according to Michael Foucault, Mary Midgley and others, ethics is the practice of freedom. How, then, are education and ethics related to one another and what do these authors mean by ‘the practice of freedom’? In this piece, I argue that education and ethics are two mutually constitutive aspects of the practice of freedom. Individuals who are able to engage in this practice can most properly be said to be the authors of their lives, that is, individuals who, to borrow from Neil MacGregor, are able to find their ‘place in things’. To find our ‘place in things’ is to do the necessary educative work required for becoming the authors of our lives, that is, for self-actualization (as Rorty and John Dewey have argued). To take on the authorial role is, moreover, to be able effectively to take control of our lives, to organize them into unities for which we are individually responsible. This, according to Midgley, is precisely what it is to be ethical. This work, moreover, requires ongoing development, that is, education, in Dewey’s sense. I further argue that professional education and skills training cannot be understood properly in isolation from these broader educational aims and I criticize mainstream educational practices for not paying sufficient attention to the intimate relationship between the vocational and non-vocational aspects of education.
- Full Text:
- Date Issued: 2020
- Authors: Tabensky, Pedro
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305672 , vital:58602 , xlink:href="https://doi.org/10.1080/00131857.2020.1791822"
- Description: On the one hand, according to Richard Rorty, Paulo Freire and others, education is the practice of freedom. On the other hand, according to Michael Foucault, Mary Midgley and others, ethics is the practice of freedom. How, then, are education and ethics related to one another and what do these authors mean by ‘the practice of freedom’? In this piece, I argue that education and ethics are two mutually constitutive aspects of the practice of freedom. Individuals who are able to engage in this practice can most properly be said to be the authors of their lives, that is, individuals who, to borrow from Neil MacGregor, are able to find their ‘place in things’. To find our ‘place in things’ is to do the necessary educative work required for becoming the authors of our lives, that is, for self-actualization (as Rorty and John Dewey have argued). To take on the authorial role is, moreover, to be able effectively to take control of our lives, to organize them into unities for which we are individually responsible. This, according to Midgley, is precisely what it is to be ethical. This work, moreover, requires ongoing development, that is, education, in Dewey’s sense. I further argue that professional education and skills training cannot be understood properly in isolation from these broader educational aims and I criticize mainstream educational practices for not paying sufficient attention to the intimate relationship between the vocational and non-vocational aspects of education.
- Full Text:
- Date Issued: 2020
The Influence of Clientelism on the Informal Sector in Zimbabwe : a Case Study of Glen View 8 Complex, Harare
- Authors: Tandire, Justin
- Date: 2021-04
- Subjects: Patron and client -- Zimbabwe -- Harare , Informal sector (Economics) -- Zimbabwe -- Harare , Informal sector (Economics) -- Political aspects -- Zimbabwe -- Harare , Patronage, Political -- Zimbabwe -- Harare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe -- Social conditions , Glen View Complex 8 (Zimbabwe)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177986 , vital:42896 , 10.21504/10962/177986
- Description: This study focuses on the influence of clientelism in the informal sector of Zimbabwe in Glen View 8 (Complex). The study used the case of Glen view 8 (complex) in Harare Province. The study focused on political dynamics in the informal sector; livelihood strategies employed by informal sector operators; manifestation of “Big Men”, social networks in the informal sector; and different strategies employed by operators to overcome the problems of political manipulation, clientelism and patronage. It employs a qualitative research methodology to enable a nuanced comprehension of the clientelistic relationships that take place in the informal sector of Zimbabwe. Through in-depth interviews, focus group discussions, narratives and in-depth interviews with key informants, the study explored the clientelistic nature of the informal sector. The major findings of the study are that the informal sector in Zimbabwe is influenced by political patronage. It was established that patronage influences the informal sector in Zimbabwe in general and at Glen View Complex 8 in particular. Some of the operators revealed that patronage negatively affects their business as they are sometimes forced to attend political party meetings either at the complex or at ZANU-PF star rallies in town. The operators experience a plethora of problems such as lack of security, poor sanitation, stiff competition, poor infrastructure, lack of insurance and fire outbreaks. It has been revealed that most of the problems experienced at the complex are a result of the politicisation of the informal sector particularly by the ZANU-PF party. Operators at the complex have described the politicisation of the informal sector as a major drawback to their efforts of realising maximum benefits from their work. Therefore, the thrust of this thesis is premised on the de-politicisation of the informal sector as the starting point in the transformation of the activities of the operators. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Tandire, Justin
- Date: 2021-04
- Subjects: Patron and client -- Zimbabwe -- Harare , Informal sector (Economics) -- Zimbabwe -- Harare , Informal sector (Economics) -- Political aspects -- Zimbabwe -- Harare , Patronage, Political -- Zimbabwe -- Harare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe -- Social conditions , Glen View Complex 8 (Zimbabwe)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177986 , vital:42896 , 10.21504/10962/177986
- Description: This study focuses on the influence of clientelism in the informal sector of Zimbabwe in Glen View 8 (Complex). The study used the case of Glen view 8 (complex) in Harare Province. The study focused on political dynamics in the informal sector; livelihood strategies employed by informal sector operators; manifestation of “Big Men”, social networks in the informal sector; and different strategies employed by operators to overcome the problems of political manipulation, clientelism and patronage. It employs a qualitative research methodology to enable a nuanced comprehension of the clientelistic relationships that take place in the informal sector of Zimbabwe. Through in-depth interviews, focus group discussions, narratives and in-depth interviews with key informants, the study explored the clientelistic nature of the informal sector. The major findings of the study are that the informal sector in Zimbabwe is influenced by political patronage. It was established that patronage influences the informal sector in Zimbabwe in general and at Glen View Complex 8 in particular. Some of the operators revealed that patronage negatively affects their business as they are sometimes forced to attend political party meetings either at the complex or at ZANU-PF star rallies in town. The operators experience a plethora of problems such as lack of security, poor sanitation, stiff competition, poor infrastructure, lack of insurance and fire outbreaks. It has been revealed that most of the problems experienced at the complex are a result of the politicisation of the informal sector particularly by the ZANU-PF party. Operators at the complex have described the politicisation of the informal sector as a major drawback to their efforts of realising maximum benefits from their work. Therefore, the thrust of this thesis is premised on the de-politicisation of the informal sector as the starting point in the transformation of the activities of the operators. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2021
- Full Text:
- Date Issued: 2021-04
Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys)
- Taylor, Peter J, Kearney, Theresa, Dalton, Desire L, Chakona, Gamuchirai, Kelly, Christopher M, Barker, Nigel P
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
- Date Issued: 2020
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
- Date Issued: 2020
In Vitro Studies on Antioxidant and AntiParasitic Activities of Compounds Isolated from Rauvolfia caffra Sond
- Tlhapi, Dorcas B, Ramaite, Isaiah D, Anokwuru, Chinedu P, van Ree, Teunis, Hoppe, Heinrich C
- Authors: Tlhapi, Dorcas B , Ramaite, Isaiah D , Anokwuru, Chinedu P , van Ree, Teunis , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425993 , vital:72305 , xlink:href="https://doi.org/10.3390/molecules25173781"
- Description: As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 μg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 μg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.
- Full Text:
- Date Issued: 2020
- Authors: Tlhapi, Dorcas B , Ramaite, Isaiah D , Anokwuru, Chinedu P , van Ree, Teunis , Hoppe, Heinrich C
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425993 , vital:72305 , xlink:href="https://doi.org/10.3390/molecules25173781"
- Description: As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 μg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 μg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.
- Full Text:
- Date Issued: 2020
Exploring a systems approach to mainstreaming sustainability in universities: A case study of Rhodes University in South Africa
- Togo, Muchaiteyi, Lotz-Sisitka, Heila
- Authors: Togo, Muchaiteyi , Lotz-Sisitka, Heila
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182857 , vital:43886 , xlink:href="https://doi.org/10.1080/13504622.2012.749974"
- Description: This paper explores the use of systems theory to inform the mainstreaming of sustainability in a university’s functions as it responds to sustainable development challenges in its local context. Offering a case study of Rhodes University, the paper shows how the use of systems models and concepts, underpinned by a critical realist ontology and an understanding of morphogenetic change processes, have the potential to enable universities to mobilise their operations to respond to local sustainability challenges. In this instance, the success of such an approach is shown to depend on commitments from the university community and the availability of enabling inputs, such as financial and human resources. The paper concludes with reflections and recommendations to inform further development of a newly emerging systems approach in sustainability mainstreaming at Rhodes University, and other institutions pursuing similar approaches and goals.
- Full Text:
- Date Issued: 2013
- Authors: Togo, Muchaiteyi , Lotz-Sisitka, Heila
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182857 , vital:43886 , xlink:href="https://doi.org/10.1080/13504622.2012.749974"
- Description: This paper explores the use of systems theory to inform the mainstreaming of sustainability in a university’s functions as it responds to sustainable development challenges in its local context. Offering a case study of Rhodes University, the paper shows how the use of systems models and concepts, underpinned by a critical realist ontology and an understanding of morphogenetic change processes, have the potential to enable universities to mobilise their operations to respond to local sustainability challenges. In this instance, the success of such an approach is shown to depend on commitments from the university community and the availability of enabling inputs, such as financial and human resources. The paper concludes with reflections and recommendations to inform further development of a newly emerging systems approach in sustainability mainstreaming at Rhodes University, and other institutions pursuing similar approaches and goals.
- Full Text:
- Date Issued: 2013
A narrative study of students’ and staff’s experiences of living with HIV and AIDS at Rhodes University
- Authors: Tsope, Lindiwe
- Date: 2021-04
- Subjects: AIDS (Disease) South Africa Makhanda , HIV infections South Africa Makhanda , College students Health and hygiene South Africa Makhanda , Universities and colleges South Africa Makhanda Employees Health and hygiene , Stigma (Social psychology) , AIDS (Disease) Social aspects South Africa Makhanda , HIV infections Social aspects South Africa Makhanda , AIDS (Disease) Psychological aspects , HIV infections Psychological aspects , Health counseling South Africa Makhanda , Discourse analysis, Narrative
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/176894 , vital:42769 , 10.21504/10962/176894
- Description: A narrative study of students’ and staff’s experiences of living with HIV and AIDS at Rhodes University Research on HIV and AIDS in university settings, especially research exploring the experience of living with the disease, has been minimal. As a response to the knowledge and research gaps, this thesis is a qualitative study involving students and staff living with HIV (LWH) and accessing treatment (ART) at the Rhodes University Health Care Centre. This study explored the personal and social symbolisms as well as meanings attached to living with HIV, through in-depth interviews with ten students and staff living with HIV, all purposively sampled and recruited through the Rhodes University Health Care Centre. Using social constructionism, symbolic interactionism and the theory of biographical disruption, the narratives revealed a positive and inspirational side of living with HIV and AIDS – especially emphasizing that PLWHA do not have to surrender to the deadly narrative of the disease. It became evident that stigma, both internal and external, largely influences illness narratives. Furthermore, the study revealed the social reconstruction of life narratives both in order to understand the illness in terms of past social experiences and to reaffirm the impression that life has a course and the self has a purpose. All participants found that accessing treatment from the Rhodes University Health Care Centre positively influenced their experiences of adherence and reconstruction of narratives. The study indicates that HIV-related interventions in place at the university need to pay more attention to the psychosocial needs of PLWH, involvement of PWLH, as well as keeping up with the continuously changing global HIV narrative. The study argues for more attention to in-depth experiences and personal narratives in HIV and AIDS, and PLWHA education at Rhodes University. , Thesis (PhD) -- Humanities, Department of Sociology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Tsope, Lindiwe
- Date: 2021-04
- Subjects: AIDS (Disease) South Africa Makhanda , HIV infections South Africa Makhanda , College students Health and hygiene South Africa Makhanda , Universities and colleges South Africa Makhanda Employees Health and hygiene , Stigma (Social psychology) , AIDS (Disease) Social aspects South Africa Makhanda , HIV infections Social aspects South Africa Makhanda , AIDS (Disease) Psychological aspects , HIV infections Psychological aspects , Health counseling South Africa Makhanda , Discourse analysis, Narrative
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/176894 , vital:42769 , 10.21504/10962/176894
- Description: A narrative study of students’ and staff’s experiences of living with HIV and AIDS at Rhodes University Research on HIV and AIDS in university settings, especially research exploring the experience of living with the disease, has been minimal. As a response to the knowledge and research gaps, this thesis is a qualitative study involving students and staff living with HIV (LWH) and accessing treatment (ART) at the Rhodes University Health Care Centre. This study explored the personal and social symbolisms as well as meanings attached to living with HIV, through in-depth interviews with ten students and staff living with HIV, all purposively sampled and recruited through the Rhodes University Health Care Centre. Using social constructionism, symbolic interactionism and the theory of biographical disruption, the narratives revealed a positive and inspirational side of living with HIV and AIDS – especially emphasizing that PLWHA do not have to surrender to the deadly narrative of the disease. It became evident that stigma, both internal and external, largely influences illness narratives. Furthermore, the study revealed the social reconstruction of life narratives both in order to understand the illness in terms of past social experiences and to reaffirm the impression that life has a course and the self has a purpose. All participants found that accessing treatment from the Rhodes University Health Care Centre positively influenced their experiences of adherence and reconstruction of narratives. The study indicates that HIV-related interventions in place at the university need to pay more attention to the psychosocial needs of PLWH, involvement of PWLH, as well as keeping up with the continuously changing global HIV narrative. The study argues for more attention to in-depth experiences and personal narratives in HIV and AIDS, and PLWHA education at Rhodes University. , Thesis (PhD) -- Humanities, Department of Sociology, 2021
- Full Text:
- Date Issued: 2021-04
Multiplexed Mass Spectrometry: Single, On-Bead, Detection Analysis Using MALDI-TOF MS
- Authors: Twala, Busisiwe Victoria
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164693 , vital:41155 , doi:10.21504/10962/164693
- Description: Thesis (PhD)--Rhodes University, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Twala, Busisiwe Victoria
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164693 , vital:41155 , doi:10.21504/10962/164693
- Description: Thesis (PhD)--Rhodes University, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Exploring the structural integrity of a picornavirus capsid
- Authors: Upfold, Nicole Sarah
- Date: 2020
- Subjects: Picornaviruses , Immunoglobulins , Capsids (Virology) , Viruses Morphology , RNA viruses
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/131837 , vital:36758 , DOI https://doi.org/10.21504/10962/131837
- Description: Picornaviruses are a diverse family of small RNA viruses that cause a broad range of human and veterinary diseases. Despite decades of research into the molecular biology of these pathogens, no antivirals and few vaccines are commercially available for the treatment and prevention of picornavirus infections. The capsids of these non-enveloped viruses are involved in many important aspects of the picornavirus lifecycle, such as cell attachment and entry, uncoating, and protection of the viral RNA. Although the structures of many picornavirus capsids have been solved, a broader understanding of the molecular determinants that are required for structural integrity and stability is imperative for an improved understanding of the basic biology of these viruses, and for designing effective control strategies. Collectively, this thesis aims to elucidate the molecular determinants of structural stability and integrity in the Theiler’s murine encephalomyelitis virus capsid (TMEV). To study the TMEV GDVII capsid using biochemical techniques, neutralising polyclonal antibodies were generated against GDVII particles. The antibodies recognised linear epitopes in the C-terminus of the VP1 protein, but not those present in VP2 or VP3. The VP1 C-terminal residues were mapped to a loop above the putative receptor binding pit on the capsid surface, which prompted an investigation into the potential binding site of the TMEV co-receptor, heparan sulphate. Molecular docking revealed that heparan interacts with residues of the receptor binding pocket, as well as residues of the adjoining VP1 C-terminal loop. These findings suggest that the antibodies neutralise virus infection by preventing attachment of the virus to the co-receptor and possibly the unknown primary receptor. Few studies have identified the specific residues and interactions at subunit interfaces that significantly contribute to picornavirus capsid stability, assembly, and function. A novel in-silico screen was developed for the prediction of hotspot residues at protein-protein interfaces of a virus capsid. This screen can be applied to elucidate the residues that contribute significantly to the intraprotomer, interprotomer and interpentamer interfaces of any picornavirus capsid, on condition that the structure of the virus is available. The screen was applied to TMEV GDVII resulting in the identification of hotspots, several of which correspond to residues that are known to be important for aspects of the virus lifecycle, such as those that contribute to pH stability or form part of receptor binding sites. This observation suggests that residues involved in specific capsid functions may also play a role in capsid stability. Many of the residues identified as hotspots in TMEV corresponded to those required for assembly, uncoating, and virus growth in representative picornaviruses from various genera, suggesting that the residues that regulate capsid stability may be somewhat conserved across the family. Hotspots identified at the interpentamer interfaces of TMEV were individually substituted to alanine to further explore their importance to the TMEV lifecycle. All the amino acid substitutions prevented completion of the virus lifecycle as no CPE was observed following transfection of susceptible cells. Immunofluorescence experiments demonstrated that virus protein synthesis and RNA replication were not inhibited by substitution of the hotspot residues, but that infectivity was severely impeded. This confirmed that the residues were required for some aspect of the virus lifecycle, such as capsid assembly, or were critical for maintaining the conformational stability of the TMEV particles. Virus capsids become unstable and are prone to dissociation under certain conditions such as extreme pH and non-physiological temperatures. The thermostability of TMEV was explored by selecting GDVII virions with improved thermal tolerance through serial passage and heat exposure. Thermostable virions that could tolerate temperatures above 57 °C had reduced infective titres compared to the wild type TMEV suggesting that the virus adapted to thermal stress at the expense of viral fitness. Sequencing the capsid encoding regions of the mutant virions revealed a pair of amino acid substitutions that were present in all mutants. Additional substitutions that were unique to viruses selected at different temperatures were also identified. Most of the substitutions were located within the intraprotomer interfaces of the virus, unlike previous studies on enteroviruses where mutations were mostly localised to the receptor binding pocket. This thesis provides the first analysis of the structural determinants of TMEV capsid stability. The generation of tools to further explore the capsid structures of TMEV and other picornaviruses provides an opportunity for future studies which may contribute to the development of novel control strategies against this important family of viruses. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text: false
- Date Issued: 2020
- Authors: Upfold, Nicole Sarah
- Date: 2020
- Subjects: Picornaviruses , Immunoglobulins , Capsids (Virology) , Viruses Morphology , RNA viruses
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/131837 , vital:36758 , DOI https://doi.org/10.21504/10962/131837
- Description: Picornaviruses are a diverse family of small RNA viruses that cause a broad range of human and veterinary diseases. Despite decades of research into the molecular biology of these pathogens, no antivirals and few vaccines are commercially available for the treatment and prevention of picornavirus infections. The capsids of these non-enveloped viruses are involved in many important aspects of the picornavirus lifecycle, such as cell attachment and entry, uncoating, and protection of the viral RNA. Although the structures of many picornavirus capsids have been solved, a broader understanding of the molecular determinants that are required for structural integrity and stability is imperative for an improved understanding of the basic biology of these viruses, and for designing effective control strategies. Collectively, this thesis aims to elucidate the molecular determinants of structural stability and integrity in the Theiler’s murine encephalomyelitis virus capsid (TMEV). To study the TMEV GDVII capsid using biochemical techniques, neutralising polyclonal antibodies were generated against GDVII particles. The antibodies recognised linear epitopes in the C-terminus of the VP1 protein, but not those present in VP2 or VP3. The VP1 C-terminal residues were mapped to a loop above the putative receptor binding pit on the capsid surface, which prompted an investigation into the potential binding site of the TMEV co-receptor, heparan sulphate. Molecular docking revealed that heparan interacts with residues of the receptor binding pocket, as well as residues of the adjoining VP1 C-terminal loop. These findings suggest that the antibodies neutralise virus infection by preventing attachment of the virus to the co-receptor and possibly the unknown primary receptor. Few studies have identified the specific residues and interactions at subunit interfaces that significantly contribute to picornavirus capsid stability, assembly, and function. A novel in-silico screen was developed for the prediction of hotspot residues at protein-protein interfaces of a virus capsid. This screen can be applied to elucidate the residues that contribute significantly to the intraprotomer, interprotomer and interpentamer interfaces of any picornavirus capsid, on condition that the structure of the virus is available. The screen was applied to TMEV GDVII resulting in the identification of hotspots, several of which correspond to residues that are known to be important for aspects of the virus lifecycle, such as those that contribute to pH stability or form part of receptor binding sites. This observation suggests that residues involved in specific capsid functions may also play a role in capsid stability. Many of the residues identified as hotspots in TMEV corresponded to those required for assembly, uncoating, and virus growth in representative picornaviruses from various genera, suggesting that the residues that regulate capsid stability may be somewhat conserved across the family. Hotspots identified at the interpentamer interfaces of TMEV were individually substituted to alanine to further explore their importance to the TMEV lifecycle. All the amino acid substitutions prevented completion of the virus lifecycle as no CPE was observed following transfection of susceptible cells. Immunofluorescence experiments demonstrated that virus protein synthesis and RNA replication were not inhibited by substitution of the hotspot residues, but that infectivity was severely impeded. This confirmed that the residues were required for some aspect of the virus lifecycle, such as capsid assembly, or were critical for maintaining the conformational stability of the TMEV particles. Virus capsids become unstable and are prone to dissociation under certain conditions such as extreme pH and non-physiological temperatures. The thermostability of TMEV was explored by selecting GDVII virions with improved thermal tolerance through serial passage and heat exposure. Thermostable virions that could tolerate temperatures above 57 °C had reduced infective titres compared to the wild type TMEV suggesting that the virus adapted to thermal stress at the expense of viral fitness. Sequencing the capsid encoding regions of the mutant virions revealed a pair of amino acid substitutions that were present in all mutants. Additional substitutions that were unique to viruses selected at different temperatures were also identified. Most of the substitutions were located within the intraprotomer interfaces of the virus, unlike previous studies on enteroviruses where mutations were mostly localised to the receptor binding pocket. This thesis provides the first analysis of the structural determinants of TMEV capsid stability. The generation of tools to further explore the capsid structures of TMEV and other picornaviruses provides an opportunity for future studies which may contribute to the development of novel control strategies against this important family of viruses. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
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- Date Issued: 2020