Morphological, genetic and biological characterisation of a novel alphabaculovirus isolated from Cryptophlebia peltastica (Lepidoptera: Tortricidae)
- Marsberg, Tamryn, Jukes, Michael, Krejmer-Rabalska, Martyna, Rabalski, Lukasz, Knox, Caroline, Moore, Sean D, Hill, Martin P, Szewczyk, Boguslaw
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2018
Optical limiting properties of 3, 5-dipyrenylvinyleneBODIPY dyes at 532 nm
- Kubheka, Gugu, Sanusi, Kayode, Mack, John, Nyokong, Tebello
- Authors: Kubheka, Gugu , Sanusi, Kayode , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237938 , vital:50567 , xlink:href="https://doi.org/10.1016/j.saa.2017.10.021"
- Description: The optical limiting (OL) properties of 3,5-dipyrenylvinyleneBODIPY dyes that contain both electron withdrawing and donating moieties have been investigated by using the z-scan technique at 532 nm in the nanosecond pulse range. The extension of the π-conjugation at the 3,5-positions with pyrenylvinylene groups results in a ca. 200 nm red shift of the main BODIPY spectral band to ca. 700 nm, so there is relatively weak absorbance at 532 nm under ambient light conditions. Reverse saturable absorbance (RSA) profiles are observed in response to incident pulsed laser light that is consistent with a two photon absorption-assisted excited state absorption (ESA) mechanism in CH2Cl2 solution and when the dyes are embedded in poly(bisphenol carbonate A) (PBC) polymer thin films. This demonstrates that 3,5-divinyleneBODIPY dyes are potentially suitable for use in OL applications, since limiting threshold fluence (Ilim) values of below 0.95 J cm−2 are observed when thin films are prepared.
- Full Text:
- Date Issued: 2018
- Authors: Kubheka, Gugu , Sanusi, Kayode , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237938 , vital:50567 , xlink:href="https://doi.org/10.1016/j.saa.2017.10.021"
- Description: The optical limiting (OL) properties of 3,5-dipyrenylvinyleneBODIPY dyes that contain both electron withdrawing and donating moieties have been investigated by using the z-scan technique at 532 nm in the nanosecond pulse range. The extension of the π-conjugation at the 3,5-positions with pyrenylvinylene groups results in a ca. 200 nm red shift of the main BODIPY spectral band to ca. 700 nm, so there is relatively weak absorbance at 532 nm under ambient light conditions. Reverse saturable absorbance (RSA) profiles are observed in response to incident pulsed laser light that is consistent with a two photon absorption-assisted excited state absorption (ESA) mechanism in CH2Cl2 solution and when the dyes are embedded in poly(bisphenol carbonate A) (PBC) polymer thin films. This demonstrates that 3,5-divinyleneBODIPY dyes are potentially suitable for use in OL applications, since limiting threshold fluence (Ilim) values of below 0.95 J cm−2 are observed when thin films are prepared.
- Full Text:
- Date Issued: 2018
Optical nonlinearity of pentadecylphenoxyl substituted sandwich–type metallophthalocyanines in the presence of Ag–CdSeTe/ZnTeSe nanocrystals: Effects of conjugation and central metals
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187899 , vital:44708 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.01.009"
- Description: Novel pentadecylphenoxyl substituted homoleptic sandwich–type metallophthalocyanines: bis (complexes 2 and 4 containing Eu and Dy, respectively) and tris (complexes 3 and 5 containing Eu and Dy, respectively) 2,9,16,23–tetrakis–(3–pentadecylphenoxyl) phthalocyanines and cadmium based (Ag–CdSeTe/ZnTeSe) nanocrystals (NCs) were synthesized. The nonlinear optical (NLO) behavior of the metallophthalocyanines and their composites with NCs were investigated using the open aperture Z–scan technique at excitation wavelength of 532 nm with 10 ns pulse. All of the samples exhibited interesting NLO attributes: among all the sandwich–type complexes, complex 5 afforded the most efficient NLO features accounting for large nonlinear absorption coefficient (βeff) value of 3500 cm/GW and limiting threshold (Ilim) value of 0.43 J cm−2. Overall, the composites of the triple decker sandwich–type complexes with Ag–CdSeTe/ZnTeSe yielded the best NLO characteristics with 3 and 5 accounting for the largest βeff value of 5500 cm/GW and Ilim value of 0.09 J cm−2. The synthesized complexes and their composites with NCs could be viable and efficient NLO absorber due to their interesting NLO activities.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187899 , vital:44708 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.01.009"
- Description: Novel pentadecylphenoxyl substituted homoleptic sandwich–type metallophthalocyanines: bis (complexes 2 and 4 containing Eu and Dy, respectively) and tris (complexes 3 and 5 containing Eu and Dy, respectively) 2,9,16,23–tetrakis–(3–pentadecylphenoxyl) phthalocyanines and cadmium based (Ag–CdSeTe/ZnTeSe) nanocrystals (NCs) were synthesized. The nonlinear optical (NLO) behavior of the metallophthalocyanines and their composites with NCs were investigated using the open aperture Z–scan technique at excitation wavelength of 532 nm with 10 ns pulse. All of the samples exhibited interesting NLO attributes: among all the sandwich–type complexes, complex 5 afforded the most efficient NLO features accounting for large nonlinear absorption coefficient (βeff) value of 3500 cm/GW and limiting threshold (Ilim) value of 0.43 J cm−2. Overall, the composites of the triple decker sandwich–type complexes with Ag–CdSeTe/ZnTeSe yielded the best NLO characteristics with 3 and 5 accounting for the largest βeff value of 5500 cm/GW and Ilim value of 0.09 J cm−2. The synthesized complexes and their composites with NCs could be viable and efficient NLO absorber due to their interesting NLO activities.
- Full Text:
- Date Issued: 2018
Optimizing phthalocyanine based dye-sensitized solar cells: The role of reduced graphene oxide
- Chindeka, Francis, Mashazi, Philani N, Britton, Jonathan, Fomo, Gertrude, Oluwole, David O, Sindelo, Azole, Nyokong, Tebello
- Authors: Chindeka, Francis , Mashazi, Philani N , Britton, Jonathan , Fomo, Gertrude , Oluwole, David O , Sindelo, Azole , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187770 , vital:44695 , xlink:href="https://doi.org/10.1016/j.synthmet.2018.10.021"
- Description: Dye-sensitized solar cells (DSSC) were fabricated by incorporating graphene materials as catalysts at the counter electrode. Platinum was also used as a catalyst for comparison purposes. Different phthalocyanines: hydroxyl indium tetracarboxyphenoxy phthalocyanine (1), chloro indium octacarboxy phthalocyanine (2) and dibenzoic acid silicon phthalocyanine (3) were used as dyes. Complex 3 gave the highest power conversion efficiency (η) of 3.19% when using nitrogen doped reduced graphene oxide nanosheets (NrGONS) as a catalyst at the counter electrode, and TiO2 containing rGONS at the anode. The value is close to 3.8% obtained when using Pt catalyst instead of NrGONS at the cathode, thus confirming that NrGONS is a promising candidate to replace the more expensive Pt. The study also shows that placing rGONS on both the anode and cathode improves efficiency.
- Full Text:
- Date Issued: 2018
- Authors: Chindeka, Francis , Mashazi, Philani N , Britton, Jonathan , Fomo, Gertrude , Oluwole, David O , Sindelo, Azole , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187770 , vital:44695 , xlink:href="https://doi.org/10.1016/j.synthmet.2018.10.021"
- Description: Dye-sensitized solar cells (DSSC) were fabricated by incorporating graphene materials as catalysts at the counter electrode. Platinum was also used as a catalyst for comparison purposes. Different phthalocyanines: hydroxyl indium tetracarboxyphenoxy phthalocyanine (1), chloro indium octacarboxy phthalocyanine (2) and dibenzoic acid silicon phthalocyanine (3) were used as dyes. Complex 3 gave the highest power conversion efficiency (η) of 3.19% when using nitrogen doped reduced graphene oxide nanosheets (NrGONS) as a catalyst at the counter electrode, and TiO2 containing rGONS at the anode. The value is close to 3.8% obtained when using Pt catalyst instead of NrGONS at the cathode, thus confirming that NrGONS is a promising candidate to replace the more expensive Pt. The study also shows that placing rGONS on both the anode and cathode improves efficiency.
- Full Text:
- Date Issued: 2018
Photodynamic therapy activity of zinc phthalocyanine linked to folic acid and magnetic nanoparticles
- Matlou, Gauta G, Oluwole, David O, Prinsloo, Earl, Nyokong, Tebello
- Authors: Matlou, Gauta G , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234429 , vital:50195 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2018.07.025"
- Description: In this work, the photodynamic therapy (PDT) activities (using human carcinoma adherent MCF-7 cells) of zinc phthalocyanine derivatives: complexes 1 (Zn mono cinnamic acid phthalocyanine) and 2 (zinc mono carboxyphenoxy phthalocyanine) when covalently linked to folic acid (FA) and amine functionalized magnetic nanoparticles (AMNPs) are reported. The covalent linkage of asymmetric zinc cinnamic acid Pc (1) to FA (1-FA) through an amide bond is reported for the first time. Complex 1 is insoluble in water, but upon linkage to FA, (to form 1-FA) the molecule become water soluble, hence the UV–Vis spectrum and singlet oxygen quantum yield for 1-FA were also done in water since water solubility is essential for biological applications. The reported 2-FA is also water soluble. Linking complexes 1 and 2 to FA and AMNPs decreased the dark toxicity of 1 and 2 on MCF-7 cells. Pc-FA (1-FA and 2-FA) conjugates had better singlet oxygen quantum yields (Φ∆) in DMSO as compared to Pc-AMNPs (1-AMNPs and 2-AMNPs). The water- soluble 1-FA and 2-FA also achieved a better photodynamic therapy (PDT) activity as compared to 1-AMNPs and 2-AMNPs. Folic acid targeting on the tumor cells may have also facilitated better bioavailability of 1-FA and 2-FA and improved PDT activity on MCF-7 cells over AMNPs carriers.
- Full Text:
- Date Issued: 2018
Photodynamic therapy activity of zinc phthalocyanine linked to folic acid and magnetic nanoparticles
- Authors: Matlou, Gauta G , Oluwole, David O , Prinsloo, Earl , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234429 , vital:50195 , xlink:href="https://doi.org/10.1016/j.jphotobiol.2018.07.025"
- Description: In this work, the photodynamic therapy (PDT) activities (using human carcinoma adherent MCF-7 cells) of zinc phthalocyanine derivatives: complexes 1 (Zn mono cinnamic acid phthalocyanine) and 2 (zinc mono carboxyphenoxy phthalocyanine) when covalently linked to folic acid (FA) and amine functionalized magnetic nanoparticles (AMNPs) are reported. The covalent linkage of asymmetric zinc cinnamic acid Pc (1) to FA (1-FA) through an amide bond is reported for the first time. Complex 1 is insoluble in water, but upon linkage to FA, (to form 1-FA) the molecule become water soluble, hence the UV–Vis spectrum and singlet oxygen quantum yield for 1-FA were also done in water since water solubility is essential for biological applications. The reported 2-FA is also water soluble. Linking complexes 1 and 2 to FA and AMNPs decreased the dark toxicity of 1 and 2 on MCF-7 cells. Pc-FA (1-FA and 2-FA) conjugates had better singlet oxygen quantum yields (Φ∆) in DMSO as compared to Pc-AMNPs (1-AMNPs and 2-AMNPs). The water- soluble 1-FA and 2-FA also achieved a better photodynamic therapy (PDT) activity as compared to 1-AMNPs and 2-AMNPs. Folic acid targeting on the tumor cells may have also facilitated better bioavailability of 1-FA and 2-FA and improved PDT activity on MCF-7 cells over AMNPs carriers.
- Full Text:
- Date Issued: 2018
Photophysical and strong optical limiting properties of ball-type phthalocyanines dimers and their monomeric analogues
- Nwaji, Njemuwa, Mack, John, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187930 , vital:44711 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.10.045"
- Description: The nonlinear optical behaviors of ball-type phthalocyanine complexes: 1′,11,’15′,25′-tetrakis-[4,4′-((4-formyl-1,2-bisphenoxyl))bis(phthalocyaninato zinc (II)] (5), 1′,11,’15′,25′-tetrakis-[4,4′-((4-formyl-1,2-bisphenoxyl) bis(phthalocyaninato gallium (III) chloride)] (6), and 1′, 11,’15′,25′-tetrakis-4,4′-((4-formyl-1,2-phenoxyl)bis(phthalocyaninato indium (III) chloride)] (7) and the corresponding monomeric derivatives 8–10 were investigated using nanosecond pulse open aperture Z-scan technique at 532 nm. The nonlinear response showed strong reverse saturable absorption for all the complexes both in solution and when embedded in polymer matrix. The dimeric complexes showed better optical limiting properties compared to the monomeric derivatives. The βeff values for the dimeric complexes 5–7 were found to be 48.5, 55.2, and 60.1 cm/GW for 5, 6A, and 7 respectively, higher than the corresponding monomeric derivatives 8–10. Enhanced optical limiting properties were observed when the complexes were formulated in thin films. The second order hyperpolarizability values were in order of 10−28–10−26 esu in solution and 10−27–10−26 in films.
- Full Text:
- Date Issued: 2018
- Authors: Nwaji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187930 , vital:44711 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.10.045"
- Description: The nonlinear optical behaviors of ball-type phthalocyanine complexes: 1′,11,’15′,25′-tetrakis-[4,4′-((4-formyl-1,2-bisphenoxyl))bis(phthalocyaninato zinc (II)] (5), 1′,11,’15′,25′-tetrakis-[4,4′-((4-formyl-1,2-bisphenoxyl) bis(phthalocyaninato gallium (III) chloride)] (6), and 1′, 11,’15′,25′-tetrakis-4,4′-((4-formyl-1,2-phenoxyl)bis(phthalocyaninato indium (III) chloride)] (7) and the corresponding monomeric derivatives 8–10 were investigated using nanosecond pulse open aperture Z-scan technique at 532 nm. The nonlinear response showed strong reverse saturable absorption for all the complexes both in solution and when embedded in polymer matrix. The dimeric complexes showed better optical limiting properties compared to the monomeric derivatives. The βeff values for the dimeric complexes 5–7 were found to be 48.5, 55.2, and 60.1 cm/GW for 5, 6A, and 7 respectively, higher than the corresponding monomeric derivatives 8–10. Enhanced optical limiting properties were observed when the complexes were formulated in thin films. The second order hyperpolarizability values were in order of 10−28–10−26 esu in solution and 10−27–10−26 in films.
- 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
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
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
Relational values about nature in protected area research
- de Vos, Alta, Bezerra, Joana C, Roux, Dirk
- Authors: de Vos, Alta , Bezerra, Joana C , Roux, Dirk
- 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
- 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
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
Special section on urbanisation and ecosystem services in sub-Saharan Africa: Current status and scenarios
- Pauleit, Stephan, Lindley, Sarah, Lotz-Sisitka, Heila, Shackleton, Charlie M
- Authors: Pauleit, Stephan , Lindley, Sarah , Lotz-Sisitka, Heila , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183082 , vital:43910 , xlink:href="https://doi.org/10.1016/j.landurbplan.2018.09.008"
- Description: The African continent is facing unprecedented population growth in the 21st century. Most of this growth will be absorbed by urban areas where the overall population is projected to triple from presently appr. 400 people to 1.3 billion people in 2050 (UN-Habitat, 2014). In sub-Saharan Africa, which is the focus of this Special Issue, not only the number of megacities with more than 10 million such as Lagos will rise, but smaller or medium sized cities will attract most of this growth (UN-Habitat, 2014). The majority of this increase is taking place in the form of informal settlements where people are living in poverty and where basic facilities and services such as a secure supply of clean drinking water and safe waste water disposal are missing.
- Full Text:
- Date Issued: 2018
- Authors: Pauleit, Stephan , Lindley, Sarah , Lotz-Sisitka, Heila , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183082 , vital:43910 , xlink:href="https://doi.org/10.1016/j.landurbplan.2018.09.008"
- Description: The African continent is facing unprecedented population growth in the 21st century. Most of this growth will be absorbed by urban areas where the overall population is projected to triple from presently appr. 400 people to 1.3 billion people in 2050 (UN-Habitat, 2014). In sub-Saharan Africa, which is the focus of this Special Issue, not only the number of megacities with more than 10 million such as Lagos will rise, but smaller or medium sized cities will attract most of this growth (UN-Habitat, 2014). The majority of this increase is taking place in the form of informal settlements where people are living in poverty and where basic facilities and services such as a secure supply of clean drinking water and safe waste water disposal are missing.
- Full Text:
- Date Issued: 2018
Synthesis, photophysicochemical and photodynamic antimicrobial chemotherapy studies of indium pyridyl phthalocyanines: Charge versus bridging atom
- Sindelo, Azole, Nyokong, Tebello
- Authors: Sindelo, Azole , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187650 , vital:44683 , xlink:href="https://doi.org/10.1016/j.ica.2018.02.020"
- Description: 2(3), 9(10), 16(17), 23(24)-Octapyridylsulfanyl phthalocyaninato chloroindium(III) (complex 1a) and its quaternized derivative 2(3), 9(10), 16(17), 23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (complex 1b) were synthesised. The triplet quantum yields were 0.53 and 0.48 while the singlet oxygen quantum yields were 0.46 and 0.33 in DMF for 1a and 1b, respectively. The photodynamic antimicrobial chemotherapy (PACT) activity of 1b (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium(III) triiodide (2) (containing 3 positive charges) and 2-[4-(N-Methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (3) (containing 4 positive charges). Complex 1b gave log reductions of 4.21, 8.30 and 3.21 for Gram(−) E. coli, Gram(+) S. aureus and C. albicans, respectively. When comparing 1b, 2 and 3, the largest log reductions for E. coli were obtained for complex 3 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
- Full Text:
- Date Issued: 2018
- Authors: Sindelo, Azole , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187650 , vital:44683 , xlink:href="https://doi.org/10.1016/j.ica.2018.02.020"
- Description: 2(3), 9(10), 16(17), 23(24)-Octapyridylsulfanyl phthalocyaninato chloroindium(III) (complex 1a) and its quaternized derivative 2(3), 9(10), 16(17), 23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (complex 1b) were synthesised. The triplet quantum yields were 0.53 and 0.48 while the singlet oxygen quantum yields were 0.46 and 0.33 in DMF for 1a and 1b, respectively. The photodynamic antimicrobial chemotherapy (PACT) activity of 1b (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium(III) triiodide (2) (containing 3 positive charges) and 2-[4-(N-Methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (3) (containing 4 positive charges). Complex 1b gave log reductions of 4.21, 8.30 and 3.21 for Gram(−) E. coli, Gram(+) S. aureus and C. albicans, respectively. When comparing 1b, 2 and 3, the largest log reductions for E. coli were obtained for complex 3 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
- Full Text:
- Date Issued: 2018
The potential use of natural resources in urban informal settlements as substitutes for financial capital during flooding emergencies
- Dalu, Mwazvita, Shackleton, Charlie M
- Authors: Dalu, Mwazvita , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179814 , vital:43191 , xlink:href="https://doi.org/10.1016/j.pce.2018.03.002"
- Description: Rapid and widespread land cover change and the subsequent loss of the buffering capacity provided by healthy ecosystems against natural hazards has resulted in increased vulnerability to natural hazards. There is an insufficient understanding of the natural resources contribution to the resilience of poor urban communities living in informal settlements and the financial implications thereof. Thus, household strategies used to recover from the October 2012 flood shock were investigated within the informal settlements of three small South African towns using questionnaires. Within the vulnerability paradigm and the sustainable livelihood framework, the study also quantified and evaluated the relative contribution of natural resources to recovery strategies and the impacts on household financial capital. We found that natural resources contributed up to 70% to recovery of households from the flood shock, most of this being to reconstruct housing structures after the flood. Factors such as household head education level, household income, kinship level, the extent of property damage and the cost associated with property rehabilitation significantly influenced the uptake of natural resources in recovery from floods, and this was variable among settlements and towns. The main findings showed that natural resources reduced household vulnerability of urban informal settlements by providing an emergency-net function that substitutes financial capital. Their inclusion in disaster management plans and responses has the potential to contribute to the sustainable livelihoods of the urban poor in the Eastern Cape, South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Dalu, Mwazvita , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179814 , vital:43191 , xlink:href="https://doi.org/10.1016/j.pce.2018.03.002"
- Description: Rapid and widespread land cover change and the subsequent loss of the buffering capacity provided by healthy ecosystems against natural hazards has resulted in increased vulnerability to natural hazards. There is an insufficient understanding of the natural resources contribution to the resilience of poor urban communities living in informal settlements and the financial implications thereof. Thus, household strategies used to recover from the October 2012 flood shock were investigated within the informal settlements of three small South African towns using questionnaires. Within the vulnerability paradigm and the sustainable livelihood framework, the study also quantified and evaluated the relative contribution of natural resources to recovery strategies and the impacts on household financial capital. We found that natural resources contributed up to 70% to recovery of households from the flood shock, most of this being to reconstruct housing structures after the flood. Factors such as household head education level, household income, kinship level, the extent of property damage and the cost associated with property rehabilitation significantly influenced the uptake of natural resources in recovery from floods, and this was variable among settlements and towns. The main findings showed that natural resources reduced household vulnerability of urban informal settlements by providing an emergency-net function that substitutes financial capital. Their inclusion in disaster management plans and responses has the potential to contribute to the sustainable livelihoods of the urban poor in the Eastern Cape, South Africa.
- Full Text:
- Date Issued: 2018
The production and commercialization of palm wine from Hyphaene coriacea and Phoenix reclinata in Zitundo area, southern Mozambique
- Martins, Angelina R O, Shackleton, Charlie M
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179802 , vital:43190 , xlink:href="https://doi.org/10.1016/j.sajb.2018.02.389"
- Description: In southern Mozambique a traditional wine is produced using the sap from two palm species, Hyphaene coriacea and Phoenix reclinata. Production of palm wine is one of the main livelihood activities in the Zitundo area. We examined the local production and trade of palm wine in the area. Using structured interviews we investigated the tapping activity, local management practices and the palm wine market, and assessed the incomes derived from palm wine sales and the tappers' perceptions on productivity, abundance and sales fluctuation. Tapping palms was practiced year round in five of the sixteen villages in the area and the mean number of palms tapped per day was 102 ± 52 per tapper. Tappers spent an average of 25 ± 18 h per week on tapping activities resulting in an average return to labour of R39 (± US$3) per hour. The mean, annual, net income from palm wine sales was R24,981 ± R12,094 (US$1878 ± 909) per tapper, which accounted for 85% ± 22% of the tappers' annual household income. Palm wine is a highly commercial commodity in Zitundo area, with an average commercialization index of 63% ± 23%, and is likely to help alleviate poverty in the area. Hyphaene coriacea was tapped more than Phoenix reclinata, although most tappers regard the wine from the latter to be of a better quality. The importance of palm tapping in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area, towards inclusion in sectoral development policies and conservation programmes.
- Full Text:
- Date Issued: 2018
- Authors: Martins, Angelina R O , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179802 , vital:43190 , xlink:href="https://doi.org/10.1016/j.sajb.2018.02.389"
- Description: In southern Mozambique a traditional wine is produced using the sap from two palm species, Hyphaene coriacea and Phoenix reclinata. Production of palm wine is one of the main livelihood activities in the Zitundo area. We examined the local production and trade of palm wine in the area. Using structured interviews we investigated the tapping activity, local management practices and the palm wine market, and assessed the incomes derived from palm wine sales and the tappers' perceptions on productivity, abundance and sales fluctuation. Tapping palms was practiced year round in five of the sixteen villages in the area and the mean number of palms tapped per day was 102 ± 52 per tapper. Tappers spent an average of 25 ± 18 h per week on tapping activities resulting in an average return to labour of R39 (± US$3) per hour. The mean, annual, net income from palm wine sales was R24,981 ± R12,094 (US$1878 ± 909) per tapper, which accounted for 85% ± 22% of the tappers' annual household income. Palm wine is a highly commercial commodity in Zitundo area, with an average commercialization index of 63% ± 23%, and is likely to help alleviate poverty in the area. Hyphaene coriacea was tapped more than Phoenix reclinata, although most tappers regard the wine from the latter to be of a better quality. The importance of palm tapping in local livelihoods and poverty alleviation needs greater acknowledgement by government and development agencies in the area, towards inclusion in sectoral development policies and conservation programmes.
- Full Text:
- Date Issued: 2018
Towards transformative social learning on the path to 1.5 degrees
- Macintyre, Thomas, Lotz-Sisitka, Heila, Wals, Arjen E, Vogel, Coleen, Tassone, Valenina
- Authors: Macintyre, Thomas , Lotz-Sisitka, Heila , Wals, Arjen E , Vogel, Coleen , Tassone, Valenina
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182461 , vital:43832 , xlink:href="https://doi.org/10.1016/j.cosust.2017.12.003"
- Description: This paper provides insights into learning orientations and approaches that encourage change and transformation on the path to achieving the 1.5 degree C target. This literature review of the climate change and education/learning interface positions relevant literature in a heuristic tool, and reveals different learning approaches to addressing climate change. We highlight that although traditional lines of departure for achieving climate targets are usually technocratic in nature, especially if a zero emissions pathway is aimed for, there is an increasing realisation that climate issues are complex, deeply intertwined with unsustainable development and cultural change, and require collective engagement. Through considering the 1.5 degree C target as a metaphor for the fundamental changes needed in society, we argue that a wide range of learning orientations, including more inclusive and transformative social learning approaches, are needed to address the colossal challenges facing society.
- Full Text:
- Date Issued: 2018
- Authors: Macintyre, Thomas , Lotz-Sisitka, Heila , Wals, Arjen E , Vogel, Coleen , Tassone, Valenina
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182461 , vital:43832 , xlink:href="https://doi.org/10.1016/j.cosust.2017.12.003"
- Description: This paper provides insights into learning orientations and approaches that encourage change and transformation on the path to achieving the 1.5 degree C target. This literature review of the climate change and education/learning interface positions relevant literature in a heuristic tool, and reveals different learning approaches to addressing climate change. We highlight that although traditional lines of departure for achieving climate targets are usually technocratic in nature, especially if a zero emissions pathway is aimed for, there is an increasing realisation that climate issues are complex, deeply intertwined with unsustainable development and cultural change, and require collective engagement. Through considering the 1.5 degree C target as a metaphor for the fundamental changes needed in society, we argue that a wide range of learning orientations, including more inclusive and transformative social learning approaches, are needed to address the colossal challenges facing society.
- Full Text:
- Date Issued: 2018
A2B type copper (III) corroles containing zero-to-five fluorine atoms
- Li, Minzhi, Niu, Yingjie, Zhu, Weihua, Mack, John, Fomo, Gertrude, Nyokong, Tebello, Liang, Xu
- Authors: Li, Minzhi , Niu, Yingjie , Zhu, Weihua , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238275 , vital:50604 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.10.044"
- Description: Four low symmetric A2B meso-substituted Cu(III)corroles with electron withdrawing meso-aryl rings have been synthesized and characterized. A detailed analysis of the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry and spectroelectrochemistry to a series of DFT and TD-DFT calculations. A series of experiments demonstrate that these Cu(III)corroles can be used as highly effective catalysts for hydrogen evolution reactions (HERs). Moreover, when the number of fluorine atoms at B meso-position is increased, there is a marked enhancement in the catalytic ability of the corrole complexes, which demonstrates that modification to the structures of low symmetry corroles is a useful strategy for developing new HER catalysts.
- Full Text:
- Date Issued: 2017
- Authors: Li, Minzhi , Niu, Yingjie , Zhu, Weihua , Mack, John , Fomo, Gertrude , Nyokong, Tebello , Liang, Xu
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/238275 , vital:50604 , xlink:href="https://doi.org/10.1016/j.dyepig.2016.10.044"
- Description: Four low symmetric A2B meso-substituted Cu(III)corroles with electron withdrawing meso-aryl rings have been synthesized and characterized. A detailed analysis of the optical and redox properties has been carried out by comparing their optical spectroscopy, electrochemistry and spectroelectrochemistry to a series of DFT and TD-DFT calculations. A series of experiments demonstrate that these Cu(III)corroles can be used as highly effective catalysts for hydrogen evolution reactions (HERs). Moreover, when the number of fluorine atoms at B meso-position is increased, there is a marked enhancement in the catalytic ability of the corrole complexes, which demonstrates that modification to the structures of low symmetry corroles is a useful strategy for developing new HER catalysts.
- Full Text:
- Date Issued: 2017