Photophysical properties of a novel styryl-BODIPY with a fused crown ether moiety
- Stone, Justin, Mack, John, Nyokong, Tebello, Kimura, Mitsumi, Kobayashi, Nagao
- Authors: Stone, Justin , Mack, John , Nyokong, Tebello , Kimura, Mitsumi , Kobayashi, Nagao
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188227 , vital:44736 , xlink:href="https://doi.org/10.1142/S1088424617500699"
- Description: The synthesis and characterization of a crown-ether-substituted 3-styrylBODIPY dye with a 4-isopropylphenyl group at the meso-position is reported. The effect that the incorporation of Na++ ions into the crown ether moiety has on the photophysical properties is investigated.
- Full Text:
- Date Issued: 2018
- Authors: Stone, Justin , Mack, John , Nyokong, Tebello , Kimura, Mitsumi , Kobayashi, Nagao
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188227 , vital:44736 , xlink:href="https://doi.org/10.1142/S1088424617500699"
- Description: The synthesis and characterization of a crown-ether-substituted 3-styrylBODIPY dye with a 4-isopropylphenyl group at the meso-position is reported. The effect that the incorporation of Na++ ions into the crown ether moiety has on the photophysical properties is investigated.
- Full Text:
- Date Issued: 2018
Photophysical studies of graphene quantum dots-Pyrene-derivatized porphyrins conjugates when encapsulated within Pluronic F127 micelles
- Managa, Muthumuni, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Managa, Muthumuni , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187971 , vital:44714 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.09.031"
- Description: Pyrene-derivatized H2, GaCl, and Zn porphyrins were immobilized on graphene quantum dots (GQDs) to form (GQDs-H2TPrP, GQDs-GaClTPrP, and GQDs-ZnTPrP) conjugates through the π-π stacking interaction method followed by encapsulating into Pluronic F127 micelles to form (GQDs-H2TPrP + F127, GQDs-GaClTPrP + F127, and GQDs-ZnTPrP + F127). Spectroscopic evidence shows that the resultant conjugates were stable due to the strong π-π stacking interaction between the GQDs and the porphyrins. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. GQDs-GaClTPrP + F127 showed highest values of the binding constant (Kb). The Stern-Volmer constant (Ksv) for GQDs-ZnTPrP + F127 were the highest compared to other porphyrins derivatives.
- Full Text:
- Date Issued: 2018
- Authors: Managa, Muthumuni , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187971 , vital:44714 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.09.031"
- Description: Pyrene-derivatized H2, GaCl, and Zn porphyrins were immobilized on graphene quantum dots (GQDs) to form (GQDs-H2TPrP, GQDs-GaClTPrP, and GQDs-ZnTPrP) conjugates through the π-π stacking interaction method followed by encapsulating into Pluronic F127 micelles to form (GQDs-H2TPrP + F127, GQDs-GaClTPrP + F127, and GQDs-ZnTPrP + F127). Spectroscopic evidence shows that the resultant conjugates were stable due to the strong π-π stacking interaction between the GQDs and the porphyrins. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. GQDs-GaClTPrP + F127 showed highest values of the binding constant (Kb). The Stern-Volmer constant (Ksv) for GQDs-ZnTPrP + F127 were the highest compared to other porphyrins derivatives.
- Full Text:
- Date Issued: 2018
Photophysicochemical behaviour and antimicrobial properties of monocarboxy Mg (II) and Al (III) phthalocyanine-magnetite conjugates
- Idowu, Mopelola A I, Xego, Solami, Arslanoglu, Yasin, Mark, John, Antunes, Edith M, Nyokong, Tebello
- Authors: Idowu, Mopelola A I , Xego, Solami , Arslanoglu, Yasin , Mark, John , Antunes, Edith M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188205 , vital:44734 , xlink:href="https://doi.org/10.1016/j.saa.2017.12.052"
- Description: Asymmetric Mg (II) or Al (III) phthalocyanine (containing a COOH group and 3-pyridylsulfanyl units) was conjugated via an amide bond to amino functionalized magnetic nanoparticle (AIMN) to form MgPc-AIMN or AlPc-AIMN conjugate, and characterized. The photophysicochemical behaviour of the phthalocyanine–AIMN conjugates was investigated and compared to the asymmetric Pcs and to the simple mixture of Pc with AIMNs without a chemical bond, (MPc-AIMN (mixed)). The directed covalent linkage of AIMNs to the asymmetrical metallopthalocyanines afforded improvements in the singlet oxygen (ФΔ) and triplet state quantum yield (ФT) as well as singlet oxygen lifetimes for the MPcs–AIMN-linked conjugates compared to MPc-AIMN (mixed) and MPcs alone. The asymmetric phthalocyanines and their conjugates showed effective antimicrobial activity against Escherichia coli bacteria under illumination.
- Full Text:
- Date Issued: 2018
- Authors: Idowu, Mopelola A I , Xego, Solami , Arslanoglu, Yasin , Mark, John , Antunes, Edith M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188205 , vital:44734 , xlink:href="https://doi.org/10.1016/j.saa.2017.12.052"
- Description: Asymmetric Mg (II) or Al (III) phthalocyanine (containing a COOH group and 3-pyridylsulfanyl units) was conjugated via an amide bond to amino functionalized magnetic nanoparticle (AIMN) to form MgPc-AIMN or AlPc-AIMN conjugate, and characterized. The photophysicochemical behaviour of the phthalocyanine–AIMN conjugates was investigated and compared to the asymmetric Pcs and to the simple mixture of Pc with AIMNs without a chemical bond, (MPc-AIMN (mixed)). The directed covalent linkage of AIMNs to the asymmetrical metallopthalocyanines afforded improvements in the singlet oxygen (ФΔ) and triplet state quantum yield (ФT) as well as singlet oxygen lifetimes for the MPcs–AIMN-linked conjugates compared to MPc-AIMN (mixed) and MPcs alone. The asymmetric phthalocyanines and their conjugates showed effective antimicrobial activity against Escherichia coli bacteria under illumination.
- Full Text:
- Date Issued: 2018
Photophysicochemical properties and photodynamic therapy activity of highly water-soluble Zn (II) phthalocyanines
- Oluwole, David O, Sari, Fatma Aslihan, Prinsloo, Earl, Dube, Edith, Yuzer, Abdulcelil, Nyokong, Tebello, Ince, Mine
- Authors: Oluwole, David O , Sari, Fatma Aslihan , Prinsloo, Earl , Dube, Edith , Yuzer, Abdulcelil , Nyokong, Tebello , Ince, Mine
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234507 , vital:50203 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.090"
- Description: The syntheses of two zinc(II) phthalocyanines (ZnPcs) having either imidazole (ZnPc 1) or pyridiloxy (ZnPc 2) moieties as their macrocycle substituents are reported. Quaternization of the ZnPcs with methyl iodide afforded water soluble cationic phthalocyanines. The photophysical, photochemical properties and photodynamic therapy (PDT) activity of the ZnPcs were studied in solution. The fluorescence quantum yield and lifetime of ZnPc 1 were higher as compared to ZnPc 2. ZnPc 2 afforded higher triplet state (ΦT) and singlet oxygen quantum yields (ΦΔ) in comparison to ZnPc 1. The PDT activity of ZnPcs was investigated against human breast adenocarcinoma cells (MCF–7). The two compounds afforded a very minimal in vitro dark cytotoxicity with 85% viable cells at concentration ≤80 μM. On irradiation of the cells having the ZnPcs, ≥50% cell death was recorded for ZnPc 1 which was also evidenced by the cells photo–micrograph.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Sari, Fatma Aslihan , Prinsloo, Earl , Dube, Edith , Yuzer, Abdulcelil , Nyokong, Tebello , Ince, Mine
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234507 , vital:50203 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.090"
- Description: The syntheses of two zinc(II) phthalocyanines (ZnPcs) having either imidazole (ZnPc 1) or pyridiloxy (ZnPc 2) moieties as their macrocycle substituents are reported. Quaternization of the ZnPcs with methyl iodide afforded water soluble cationic phthalocyanines. The photophysical, photochemical properties and photodynamic therapy (PDT) activity of the ZnPcs were studied in solution. The fluorescence quantum yield and lifetime of ZnPc 1 were higher as compared to ZnPc 2. ZnPc 2 afforded higher triplet state (ΦT) and singlet oxygen quantum yields (ΦΔ) in comparison to ZnPc 1. The PDT activity of ZnPcs was investigated against human breast adenocarcinoma cells (MCF–7). The two compounds afforded a very minimal in vitro dark cytotoxicity with 85% viable cells at concentration ≤80 μM. On irradiation of the cells having the ZnPcs, ≥50% cell death was recorded for ZnPc 1 which was also evidenced by the cells photo–micrograph.
- Full Text:
- Date Issued: 2018
Photophysics and NLO properties of Ga (III) and In (III) phthalocyaninates bearing diethyleneglycol chains
- Managa, Muthumuni, Khene, Samson M, Britton, Jonathan, Martynov, Alexander G, Gorbunova, Yulia G, Tsivadze, Aslan Y, Nyokong, Tebello
- Authors: Managa, Muthumuni , Khene, Samson M , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Y , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237822 , vital:50556 , xlink:href="https://doi.org/10.1142/S1088424618500128"
- Description: This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2′′-(2′′′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxy phthalocyanine (1H2) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.
- Full Text:
- Date Issued: 2018
- Authors: Managa, Muthumuni , Khene, Samson M , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Y , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237822 , vital:50556 , xlink:href="https://doi.org/10.1142/S1088424618500128"
- Description: This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2′′-(2′′′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxy phthalocyanine (1H2) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.
- Full Text:
- Date Issued: 2018
Physicochemical properties of water soluble unsymmetrical phthalocyanine-folic acid conjugates
- Matlou, Gauta G, Kobayashi, Nagao, Kimura, Mutsumi, Nyokong, Tebello
- Authors: Matlou, Gauta G , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233240 , vital:50071 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.10.030"
- Description: This work reports on the successful chemical linkage of folic acid (FA) to Zn mono carboxyphenoxy phthalocyanine (1) and Zn mono carboxyphenoxy tri–(tert–butyl) phthalocyanine (2). The amide bond linkage of FA to phthalocyanine (Pc) is achieved for the first time through the FA-NH2 and Pc-COOH and confirmed using FTIR, MS, elemental analysis and NMR. The linked conjugates were found to be water soluble compared to the physical mixtures of FA and Pc, which allowed for studies of singlet oxygen in water. The Pc-FA linked conjugates (1-FA and 2-FA) were found to be singlet oxygen generators with the following singlet oxygen quantum yields: 1-FA = 0.61 and 2-FA = 0.47 in DMSO and 1-FA = 0.17 and 2-FA = 0.12 in water.
- Full Text:
- Date Issued: 2018
- Authors: Matlou, Gauta G , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233240 , vital:50071 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.10.030"
- Description: This work reports on the successful chemical linkage of folic acid (FA) to Zn mono carboxyphenoxy phthalocyanine (1) and Zn mono carboxyphenoxy tri–(tert–butyl) phthalocyanine (2). The amide bond linkage of FA to phthalocyanine (Pc) is achieved for the first time through the FA-NH2 and Pc-COOH and confirmed using FTIR, MS, elemental analysis and NMR. The linked conjugates were found to be water soluble compared to the physical mixtures of FA and Pc, which allowed for studies of singlet oxygen in water. The Pc-FA linked conjugates (1-FA and 2-FA) were found to be singlet oxygen generators with the following singlet oxygen quantum yields: 1-FA = 0.61 and 2-FA = 0.47 in DMSO and 1-FA = 0.17 and 2-FA = 0.12 in water.
- Full Text:
- Date Issued: 2018
Porphyrin dimers with a bridging chiral amide-bonded benzo-moiety
- Liang, Xu, Qin, Mingfeng, Zhou, Lin, Liu, Tingting, Li, Minzhi, Mack, John, Ndebele, Nobuhle, Nyokong, Tebello, Zhu, Weihua
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
- Full Text:
- Date Issued: 2018
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
- Full Text:
- Date Issued: 2018
Postgraduate writing groups as spaces of agency development
- Oluwole, David O, Achadu, A, Asfour, Fouad-Martin, Chakona, Gamuchirai, Mason, Paul, Mataruse, P, McKenna, Sioux
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
Price determination of non-timber forest products in different areas of South Africa
- Mugido, Worship, Shackleton, Charlie M
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179825 , vital:43192 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.12.010"
- Description: A wide variety of factors can influence the price determination of non-timber forest products (NTFPs) in individual markets. However, there is little understanding of differences across multiple markets within a uniform macro context, or how they might vary between different types of NTFPs. Therefore, this study sought to determine the factors and rationale behind the setting of prices for selected NTFPs in 15 different areas of South Africa. The results showed that the pricing factors considered by sellers when setting the prices of NTFP varied with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. Overall, transport costs, stock price, profit margin, time taken to collect or produce the product and market price were the widely used factors to determine prices for NTFPs. The marked variation in both markets and products show that there was no formal or certain price setting mechanism that was used by NTFP sellers establish the market prices of NTFPs, with price discovery being the most widespread.
- Full Text:
- Date Issued: 2018
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179825 , vital:43192 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.12.010"
- Description: A wide variety of factors can influence the price determination of non-timber forest products (NTFPs) in individual markets. However, there is little understanding of differences across multiple markets within a uniform macro context, or how they might vary between different types of NTFPs. Therefore, this study sought to determine the factors and rationale behind the setting of prices for selected NTFPs in 15 different areas of South Africa. The results showed that the pricing factors considered by sellers when setting the prices of NTFP varied with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. Overall, transport costs, stock price, profit margin, time taken to collect or produce the product and market price were the widely used factors to determine prices for NTFPs. The marked variation in both markets and products show that there was no formal or certain price setting mechanism that was used by NTFP sellers establish the market prices of NTFPs, with price discovery being the most widespread.
- Full Text:
- Date Issued: 2018
Production, purification, and characterisation of proteases from an ericoid mycorrhizal fungus, Oidiodendron maius
- Authors: Manyumwa, Colleen Varaidzo
- Date: 2018
- Subjects: Ascomycetes , Mycorrhizal fungi , Ericaceae , Proteolytic enzymes , Silver Recycling
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62833 , vital:28298
- Description: The aim of this study was to produce, purify and characterise proteases from the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b/KP119480), as well as to explore their potential application in the recovery of silver from X-ray film. Firstly, the growth of the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b), was studied, and its ability to produce proteolytic enzymes was investigated. O. maius proved to grow well in the dark, submerged in Modified Melin Norkran’s liquid medium at a pH of 5 and at 25°C. Pure cultures of the fungus were maintained on Potato Dextrose Agar (PDA). The fungus grew on PDA plates containing different substrates including haemoglobin, casein, gelatin as well as azocasein. Zones of clearance, however, were only observed on plates containing gelatin after treatment with mercuric chloride, HgCl2. Proteases were successfully produced after 14 days when gelatin was incorporated into the growth medium. After production of the proteases, purification and characterisation of the enzymes was performed. Purification of the enzymes was performed by acetone precipitation followed by ultrafiltration with 50 kDa and 30 kDa cut off membrane filters. A final purification fold of approximately 37.6 was achieved. Unusual yields of above 100% were observed after each purification step with the final yield achieved being 196% with a final specific activity of 2707 U/mg. SDS-PAGE revealed a protease band of 35 kDa which was also visible on the zymogram at approximately 36 kDa. The zymogram showed clear hydrolysis bands against a blue background after staining with Coomassie Brilliant Blue. Physico-chemical characterisation of the protease revealed its pH optimum to be pH 3.0 and its temperature optimum 68°C. Another peak was observed on the pH profile at pH 7.0. The protease exhibited high thermostability at temperatures 37°C, 80°C as well as 100°C with the enzyme retaining close to 50% of its initial activity after 4 h of exposure to all three temperatures. All ions tested for their effects on the proteases, except Ca2+, enhanced protease activity. Ca2+ did not exhibit any significant effect on the enzyme’s activity while Zn2+ had the highest effect, enhancing enzyme activity by 305%. The proteases, however, were not significantly inhibited by EDTA, a metal chelating agent and a known metalloprotease inhibitor. The enzyme was classified as an aspartic protease due to complete inhibition by 25 μM of pepstatin A, coupled to its low pH optimum of 3.0. Addition of trans-Epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), a cysteine protease inhibitor, and 2-mercaptoethanol increased protease activity. The proteases exhibited a narrow substrate specificity towards gelatin and no other substrate. Substrate kinetics values were plotted on a Michaelis-Menten Graph and showed that the enzyme had a Vmax of 55.25 U/ml and a Km of 2.7 mg/ml gelatin. A low Km indicated that the protease had a high affinity for gelatin. Silver recovery studies from X-ray film revealed the proteases’ capability to remove silver from X-ray film, leaving the film intact. The recovery of silver was perceived visually, by film observation, as well as by scan electron microscopy (SEM) images, where clearance of the film was observed after incubation with the enzyme. Energy dispersive X-ray spectroscopy (EDS) profiles also confirmed removal of silver from the film, with a Ag peak showing on the profile of the film before treatment with the proteases and no peak after treatment. The crude protease sample was, however, catalytically more efficient compared to the partially purified sample. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
- Authors: Manyumwa, Colleen Varaidzo
- Date: 2018
- Subjects: Ascomycetes , Mycorrhizal fungi , Ericaceae , Proteolytic enzymes , Silver Recycling
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/62833 , vital:28298
- Description: The aim of this study was to produce, purify and characterise proteases from the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b/KP119480), as well as to explore their potential application in the recovery of silver from X-ray film. Firstly, the growth of the ericoid mycorrhizal fungus, Oidiodendron maius (CafRU082b), was studied, and its ability to produce proteolytic enzymes was investigated. O. maius proved to grow well in the dark, submerged in Modified Melin Norkran’s liquid medium at a pH of 5 and at 25°C. Pure cultures of the fungus were maintained on Potato Dextrose Agar (PDA). The fungus grew on PDA plates containing different substrates including haemoglobin, casein, gelatin as well as azocasein. Zones of clearance, however, were only observed on plates containing gelatin after treatment with mercuric chloride, HgCl2. Proteases were successfully produced after 14 days when gelatin was incorporated into the growth medium. After production of the proteases, purification and characterisation of the enzymes was performed. Purification of the enzymes was performed by acetone precipitation followed by ultrafiltration with 50 kDa and 30 kDa cut off membrane filters. A final purification fold of approximately 37.6 was achieved. Unusual yields of above 100% were observed after each purification step with the final yield achieved being 196% with a final specific activity of 2707 U/mg. SDS-PAGE revealed a protease band of 35 kDa which was also visible on the zymogram at approximately 36 kDa. The zymogram showed clear hydrolysis bands against a blue background after staining with Coomassie Brilliant Blue. Physico-chemical characterisation of the protease revealed its pH optimum to be pH 3.0 and its temperature optimum 68°C. Another peak was observed on the pH profile at pH 7.0. The protease exhibited high thermostability at temperatures 37°C, 80°C as well as 100°C with the enzyme retaining close to 50% of its initial activity after 4 h of exposure to all three temperatures. All ions tested for their effects on the proteases, except Ca2+, enhanced protease activity. Ca2+ did not exhibit any significant effect on the enzyme’s activity while Zn2+ had the highest effect, enhancing enzyme activity by 305%. The proteases, however, were not significantly inhibited by EDTA, a metal chelating agent and a known metalloprotease inhibitor. The enzyme was classified as an aspartic protease due to complete inhibition by 25 μM of pepstatin A, coupled to its low pH optimum of 3.0. Addition of trans-Epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64), a cysteine protease inhibitor, and 2-mercaptoethanol increased protease activity. The proteases exhibited a narrow substrate specificity towards gelatin and no other substrate. Substrate kinetics values were plotted on a Michaelis-Menten Graph and showed that the enzyme had a Vmax of 55.25 U/ml and a Km of 2.7 mg/ml gelatin. A low Km indicated that the protease had a high affinity for gelatin. Silver recovery studies from X-ray film revealed the proteases’ capability to remove silver from X-ray film, leaving the film intact. The recovery of silver was perceived visually, by film observation, as well as by scan electron microscopy (SEM) images, where clearance of the film was observed after incubation with the enzyme. Energy dispersive X-ray spectroscopy (EDS) profiles also confirmed removal of silver from the film, with a Ag peak showing on the profile of the film before treatment with the proteases and no peak after treatment. The crude protease sample was, however, catalytically more efficient compared to the partially purified sample. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2018
- Full Text:
- Date Issued: 2018
Prospects for biological control of cactus weeds in Namibia
- Paterson, Iain D, Manheimmer, C A, Zimmermann, Helmuth G
- Authors: Paterson, Iain D , Manheimmer, C A , Zimmermann, Helmuth G
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417522 , vital:71460 , xlink:href="https://doi.org/10.1080/09583157.2018.1562040"
- Description: Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.
- Full Text:
- Date Issued: 2018
- Authors: Paterson, Iain D , Manheimmer, C A , Zimmermann, Helmuth G
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417522 , vital:71460 , xlink:href="https://doi.org/10.1080/09583157.2018.1562040"
- Description: Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.
- Full Text:
- Date Issued: 2018
Pyridone substituted phthalocyanines: Photophysico-chemical properties and TD-DFT calculations
- Abdurrahmanoğlu, Şaziye, Canlica, Mevlüde, Mack, John, Nyokong, Tebello
- Authors: Abdurrahmanoğlu, Şaziye , Canlica, Mevlüde , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188216 , vital:44735 , xlink:href="https://doi.org/10.1142/S1088424617500730"
- Description: 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and 11H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.
- Full Text:
- Date Issued: 2018
- Authors: Abdurrahmanoğlu, Şaziye , Canlica, Mevlüde , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188216 , vital:44735 , xlink:href="https://doi.org/10.1142/S1088424617500730"
- Description: 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and 11H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.
- Full Text:
- Date Issued: 2018
Quantitation of zolpidem in biological fluids by electro-driven microextraction combined with HPLC-UV analysis
- Yaripour, Saeid, Mohammadi, Ali, Esfanjani, Isa, Walker, Roderick B, Nojavan, Saeed
- Authors: Yaripour, Saeid , Mohammadi, Ali , Esfanjani, Isa , Walker, Roderick B , Nojavan, Saeed
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184723 , vital:44266 , xlink:href="http://dx.doi.org/10.17179/excli2018-1140"
- Description: In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R2 >0.9991) with repeatability (%RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.
- Full Text:
- Date Issued: 2018
- Authors: Yaripour, Saeid , Mohammadi, Ali , Esfanjani, Isa , Walker, Roderick B , Nojavan, Saeed
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184723 , vital:44266 , xlink:href="http://dx.doi.org/10.17179/excli2018-1140"
- Description: In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R2 >0.9991) with repeatability (%RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.
- Full Text:
- Date Issued: 2018
Relational values about nature in protected area research
- de Vos, Alta, Bezerra, Joana C, Roux, Dirk J
- Authors: de Vos, Alta , Bezerra, Joana C , Roux, Dirk J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416396 , vital:71345 , xlink:href="https://doi.org/10.1016/j.cosust.2018.10.018"
- Description: Protected areas are increasingly expected to justify their existence in terms of their importance to society. However, this importance, and the complex ways in which people relate to protected areas, cannot be captured by instrumental and intrinsic value framings alone. Rather, our understanding of the role of protected areas in society needs to take account of people’s relational values about nature. Here we review the literature on values associated with human-nature connection and related concepts to highlight which approaches are currently being used to understand expressions of relational values in empirical protected area research. Our results highlights seven ‘application domains’ for relational values research, highlighting expressions of relational values, and the stakeholder focus of each. Place-focused and psychological theories were most common across these domains. This work represents a first step in developing the foundations of a relational value research agenda in protected areas.
- Full Text:
- Date Issued: 2018
- Authors: de Vos, Alta , Bezerra, Joana C , Roux, Dirk J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416396 , vital:71345 , xlink:href="https://doi.org/10.1016/j.cosust.2018.10.018"
- Description: Protected areas are increasingly expected to justify their existence in terms of their importance to society. However, this importance, and the complex ways in which people relate to protected areas, cannot be captured by instrumental and intrinsic value framings alone. Rather, our understanding of the role of protected areas in society needs to take account of people’s relational values about nature. Here we review the literature on values associated with human-nature connection and related concepts to highlight which approaches are currently being used to understand expressions of relational values in empirical protected area research. Our results highlights seven ‘application domains’ for relational values research, highlighting expressions of relational values, and the stakeholder focus of each. Place-focused and psychological theories were most common across these domains. This work represents a first step in developing the foundations of a relational value research agenda in protected areas.
- Full Text:
- Date Issued: 2018
Reproductive phenology of two Mimusops species in relation to climate, tree diameter and canopy position in Benin (West Africa)
- Sinasson Sanni, Giséle K, Shackleton, Charlie M, Sinsin, Brian
- Authors: Sinasson Sanni, Giséle K , Shackleton, Charlie M , Sinsin, Brian
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180337 , vital:43354 , xlink:href=" https://doi.org/10.1111/aje.12457"
- Description: Assessing species phenology provides useful understanding about their autecology, to contribute to management strategies. We monitored reproductive phenology of Mimusops andongensis and Mimusops kummel, and its relationship with climate, tree diameter and canopy position. We sampled trees in six diameter classes and noted their canopy position. For both species flowering began in the dry season through to the rainy season, but peaked in the dry season, whilst fruiting occurred in the rainy season and peaked during the most humid period. Flowering was positively correlated with temperature. Conversely, fruiting was negatively correlated with temperature and positively with rainfall, only in the Guineo-Sudanian zone. For M. andongensis, flowering and fruiting prevalences were positively linked to stem diameter, while only flowering was significantly related to canopy position. For M. kummel, the relationship with stem diameter was significant for flowering prevalence only and in the Guineo-Sudanian zone. Results suggest that phylogenetic membership is an important factor restricting Mimusops species phenology. Flowering and fruiting of both species are influenced by climate, and consequently climate change might shift their phenological patterns. Long-term investigations, considering flowering and fruiting abortion, will help to better understand the species phenology and perhaps predict demographic dynamics.
- Full Text:
- Date Issued: 2018
- Authors: Sinasson Sanni, Giséle K , Shackleton, Charlie M , Sinsin, Brian
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180337 , vital:43354 , xlink:href=" https://doi.org/10.1111/aje.12457"
- Description: Assessing species phenology provides useful understanding about their autecology, to contribute to management strategies. We monitored reproductive phenology of Mimusops andongensis and Mimusops kummel, and its relationship with climate, tree diameter and canopy position. We sampled trees in six diameter classes and noted their canopy position. For both species flowering began in the dry season through to the rainy season, but peaked in the dry season, whilst fruiting occurred in the rainy season and peaked during the most humid period. Flowering was positively correlated with temperature. Conversely, fruiting was negatively correlated with temperature and positively with rainfall, only in the Guineo-Sudanian zone. For M. andongensis, flowering and fruiting prevalences were positively linked to stem diameter, while only flowering was significantly related to canopy position. For M. kummel, the relationship with stem diameter was significant for flowering prevalence only and in the Guineo-Sudanian zone. Results suggest that phylogenetic membership is an important factor restricting Mimusops species phenology. Flowering and fruiting of both species are influenced by climate, and consequently climate change might shift their phenological patterns. Long-term investigations, considering flowering and fruiting abortion, will help to better understand the species phenology and perhaps predict demographic dynamics.
- Full Text:
- Date Issued: 2018
Rethinking urban green infrastructure and ecosystem services from the perspective of sub-Saharan African cities
- Lindley, Sarah, Pauleit, Stephan, Yeshitela, Kumelachew, Cilliers, Sarel, Shackleton, Charlie M
- Authors: Lindley, Sarah , Pauleit, Stephan , Yeshitela, Kumelachew , Cilliers, Sarel , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398357 , vital:69403 , xlink:href="https://doi.org/10.1016/j.landurbplan.2018.08.016"
- Description: Urban green infrastructure and its ecosystem services are often conceptualised in terms of a predominantly western perspective of cities and their wider social, economic and environmental challenges. However, the benefits which are derived from urban ecosystems are equally – if not more – important in the cities of the developing world. Cities in sub-Saharan Africa are well known to be facing severe pressures. Nevertheless, despite the challenges of rapid population change, high levels of poverty and seemingly chaotic urban development processes, there are also tremendous opportunities. Realising the opportunities around urban green infrastructure and its benefits requires harnessing the inherent local knowledge and community innovation associated with a multitude of inter-connected urban social-ecological systems. Such systems are a powerful driving force shaping urban realities. Associated planning regimes are frequently lambasted as being either absent, weakly enforced, corrupt or wholly inappropriate. Much of this criticism is justified. However, it must also be recognised that decision-makers are frequently working in contexts which lack the scientific foundations through which their decision-making might be made more effective and complementary to bottom-up initiatives. The paucity of research into urban ecosystems in sub-Saharan Africa and the lack of development of context-specific conceptual, theoretical and empirical foundations is a problem which must be addressed. Drawing on papers from a Special Issue centred on urban green infrastructure and urban ecosystem services in sub-Saharan Africa, we consider what concepts and frameworks are in use and what needs to be considered when framing future research. We also synthesise key messages from the Special Issue and draw together themes to help create a new research agenda for the international research community.
- Full Text:
- Date Issued: 2018
- Authors: Lindley, Sarah , Pauleit, Stephan , Yeshitela, Kumelachew , Cilliers, Sarel , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398357 , vital:69403 , xlink:href="https://doi.org/10.1016/j.landurbplan.2018.08.016"
- Description: Urban green infrastructure and its ecosystem services are often conceptualised in terms of a predominantly western perspective of cities and their wider social, economic and environmental challenges. However, the benefits which are derived from urban ecosystems are equally – if not more – important in the cities of the developing world. Cities in sub-Saharan Africa are well known to be facing severe pressures. Nevertheless, despite the challenges of rapid population change, high levels of poverty and seemingly chaotic urban development processes, there are also tremendous opportunities. Realising the opportunities around urban green infrastructure and its benefits requires harnessing the inherent local knowledge and community innovation associated with a multitude of inter-connected urban social-ecological systems. Such systems are a powerful driving force shaping urban realities. Associated planning regimes are frequently lambasted as being either absent, weakly enforced, corrupt or wholly inappropriate. Much of this criticism is justified. However, it must also be recognised that decision-makers are frequently working in contexts which lack the scientific foundations through which their decision-making might be made more effective and complementary to bottom-up initiatives. The paucity of research into urban ecosystems in sub-Saharan Africa and the lack of development of context-specific conceptual, theoretical and empirical foundations is a problem which must be addressed. Drawing on papers from a Special Issue centred on urban green infrastructure and urban ecosystem services in sub-Saharan Africa, we consider what concepts and frameworks are in use and what needs to be considered when framing future research. We also synthesise key messages from the Special Issue and draw together themes to help create a new research agenda for the international research community.
- Full Text:
- Date Issued: 2018
Revolutionary trends at the National Arts Festival 2017 (an overview)
- Authors: Krueger, Anton
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225563 , vital:49235 , xlink:href="https://doi.org/10.1080/10137548.2017.1407025"
- Description: My 2017 Fest Everybody's festival is different. Each individual charts their own course in navigating this vast, unwieldy, multidisciplinary festival of festivals that happens every year in the Eastern Cape. Since the long running print version of the festival paper, Cue went under this year when Standard Bank withdrew funding, I wasn't officially reviewing and this freed me up to play a bit more and to see things that appealed to me, rather than having to attend shows from a sense of obligation.
- Full Text:
- Date Issued: 2018
- Authors: Krueger, Anton
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225563 , vital:49235 , xlink:href="https://doi.org/10.1080/10137548.2017.1407025"
- Description: My 2017 Fest Everybody's festival is different. Each individual charts their own course in navigating this vast, unwieldy, multidisciplinary festival of festivals that happens every year in the Eastern Cape. Since the long running print version of the festival paper, Cue went under this year when Standard Bank withdrew funding, I wasn't officially reviewing and this freed me up to play a bit more and to see things that appealed to me, rather than having to attend shows from a sense of obligation.
- Full Text:
- Date Issued: 2018
Satisfaction with family life in South Africa: The role of socioeconomic status
- Botha, Ferdi, Booysen, Frikkie
- Authors: Botha, Ferdi , Booysen, Frikkie
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396115 , vital:69151 , xlink:href="https://doi.org/10.1007/s10902-017-9929-z"
- Description: This paper investigates the determinants of self-reported satisfaction with family life, applied to the South African context, with socioeconomic status (SES) as the main covariate and family functioning as the secondary covariate of interest. An individual-, household-, and subjective SES index is constructed via multiple correspondence analysis. Structural equation modelling (SEM) and multiple-group SEM (MGSEM) are used to analyse the role of SES in explaining satisfaction with family life. Higher levels of SES, especially household SES and subjective SES, are related to greater satisfaction with family life. Family functioning, in terms of better family flexibility, is associated with higher satisfaction with family life. The MGSEM results indicate that the role of family flexibility in explaining satisfaction with family life is similar across SES quartiles; family flexibility is an important predictor of family-life satisfaction, regardless of SES quartile.
- Full Text:
- Date Issued: 2018
- Authors: Botha, Ferdi , Booysen, Frikkie
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396115 , vital:69151 , xlink:href="https://doi.org/10.1007/s10902-017-9929-z"
- Description: This paper investigates the determinants of self-reported satisfaction with family life, applied to the South African context, with socioeconomic status (SES) as the main covariate and family functioning as the secondary covariate of interest. An individual-, household-, and subjective SES index is constructed via multiple correspondence analysis. Structural equation modelling (SEM) and multiple-group SEM (MGSEM) are used to analyse the role of SES in explaining satisfaction with family life. Higher levels of SES, especially household SES and subjective SES, are related to greater satisfaction with family life. Family functioning, in terms of better family flexibility, is associated with higher satisfaction with family life. The MGSEM results indicate that the role of family flexibility in explaining satisfaction with family life is similar across SES quartiles; family flexibility is an important predictor of family-life satisfaction, regardless of SES quartile.
- Full Text:
- Date Issued: 2018
Seed extract of Psoralea corylifolia and its constituent bakuchiol impairs AHL-based quorum sensing and biofilm formation in food-and human-related pathogens
- Husain, Fohad M, Ahmad, Iqbal, Khan, Faez I, Al-Shabib, Nasser A, Baig, Mohammad H, Hussain, Afzal, Rehman, Md T, Alajmi, Mohamed F, Lobb, Kevin A
- Authors: Husain, Fohad M , Ahmad, Iqbal , Khan, Faez I , Al-Shabib, Nasser A , Baig, Mohammad H , Hussain, Afzal , Rehman, Md T , Alajmi, Mohamed F , Lobb, Kevin A
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447182 , vital:74590 , xlink:href="https://doi.org/10.3389/fcimb.2018.00351"
- Description: The emergence of multi-drug resistance in pathogenic bacteria in clinical settings as well as food-borne infections has become a serious health concern. The problem of drug resistance necessitates the need for alternative novel therapeutic strategies to combat this menace. One such approach is targeting the quorum-sensing (QS) controlled virulence and biofilm formation. In this study, we first screened different fractions of Psoralea corylifolia (seed) for their anti-QS property in the Chromobacterium violaceum 12472 strain.
- Full Text:
- Date Issued: 2018
- Authors: Husain, Fohad M , Ahmad, Iqbal , Khan, Faez I , Al-Shabib, Nasser A , Baig, Mohammad H , Hussain, Afzal , Rehman, Md T , Alajmi, Mohamed F , Lobb, Kevin A
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447182 , vital:74590 , xlink:href="https://doi.org/10.3389/fcimb.2018.00351"
- Description: The emergence of multi-drug resistance in pathogenic bacteria in clinical settings as well as food-borne infections has become a serious health concern. The problem of drug resistance necessitates the need for alternative novel therapeutic strategies to combat this menace. One such approach is targeting the quorum-sensing (QS) controlled virulence and biofilm formation. In this study, we first screened different fractions of Psoralea corylifolia (seed) for their anti-QS property in the Chromobacterium violaceum 12472 strain.
- Full Text:
- Date Issued: 2018
Singlet oxygen generating properties of different sizes of charged Graphene quantum dot Nanoconjugates with a positively charged Phthalocyanine
- Matshitse, Refilwe, Nyokong, Tebello
- Authors: Matshitse, Refilwe , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187614 , vital:44680 , xlink:href="https://doi.org/10.1007/s10895-018-2247-y"
- Description: Various sizes of graphene quantum dots (GQDs) denoted as GQD2, GQD6 and GQD10 (increasing in size) were non-covalently attached to 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) to form GQDs-ZnTPPcQ nanoconjugates. X-ray photoelectron spectroscopy (XPS) showed that increasing sizes of GQDs decreases the atomic concentrations of oxygen, which leads to blue shift in spectra of the GQDs. Relative to Pcs alone (0.03), the presence of GQDs improved the singlet oxygen quantum yields with the following values: GQD2-ZnTPPcQ (0.17), GQD6-ZnTPPcQ (0.27) and GQD10-ZnTPPcQ (0.11). GQD2-ZnTPPcQ nanoconjugate system had the most ZnTPPcQ loading, but did not generate the most singlet oxygen species due to aggregation. This study shows that, the quantity of oxygen, size and quality of GQDs as well as amount of Pc loading are amongst the vital properties to consider when constructing GQD-nanoconjugate systems with optimal singlet oxygen quantum yields.
- Full Text:
- Date Issued: 2018
- Authors: Matshitse, Refilwe , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187614 , vital:44680 , xlink:href="https://doi.org/10.1007/s10895-018-2247-y"
- Description: Various sizes of graphene quantum dots (GQDs) denoted as GQD2, GQD6 and GQD10 (increasing in size) were non-covalently attached to 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) to form GQDs-ZnTPPcQ nanoconjugates. X-ray photoelectron spectroscopy (XPS) showed that increasing sizes of GQDs decreases the atomic concentrations of oxygen, which leads to blue shift in spectra of the GQDs. Relative to Pcs alone (0.03), the presence of GQDs improved the singlet oxygen quantum yields with the following values: GQD2-ZnTPPcQ (0.17), GQD6-ZnTPPcQ (0.27) and GQD10-ZnTPPcQ (0.11). GQD2-ZnTPPcQ nanoconjugate system had the most ZnTPPcQ loading, but did not generate the most singlet oxygen species due to aggregation. This study shows that, the quantity of oxygen, size and quality of GQDs as well as amount of Pc loading are amongst the vital properties to consider when constructing GQD-nanoconjugate systems with optimal singlet oxygen quantum yields.
- Full Text:
- Date Issued: 2018