Study of the biotransformations and microbiological properties of cymbopogon citratus
- Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015
Surface modification of silica-coated gadolinium oxide nanoparticles with zinc tetracarboxyphenoxy phthalocyanine for the photodegradation of Orange G
- Ledwaba, Mpho, Masilela, Nkosiphile, Nyokong, Tebello, Antunes, Edith M
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193621 , vital:45353 , xlink:href="https://doi.org/10.1016/j.molcata.2015.03.023"
- Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics.
- Full Text:
- Date Issued: 2015
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193621 , vital:45353 , xlink:href="https://doi.org/10.1016/j.molcata.2015.03.023"
- Description: Zinc tetracarboxyphenoxy phthalocyanine was covalently linked to Gd2O3 nanoparticles for the photocatalytic degradation of Orange G. Characterization of the composite was carried out using XRD, TEM, XPS, UV–vis spectroscopy and FT-IR spectroscopy. The composite showed improved photophysical properties over the phthalocyanine alone and the catalyst was found to be reusable. Analyses of the photodegradation rates of the azo dye indicated pseudo first-order kinetics.
- Full Text:
- Date Issued: 2015
Synthesis and characterization of Na (Y, Gd) F4 upconversion nanoparticles and an investigation of their effects on the photophysical properties of an unsubstituted tetrathiophenoxy phthalocyanine
- Taylor, Jessica M, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241437 , vital:50939 , xlink:href="https://doi.org/10.1007/s11051-015-2889-5"
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs.
- Full Text:
- Date Issued: 2015
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241437 , vital:50939 , xlink:href="https://doi.org/10.1007/s11051-015-2889-5"
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs.
- Full Text:
- Date Issued: 2015
Synthesis and characterization of ZnO nanoparticle synthesized by a microwave-assisted combustion method and catalytic activity for the removal of ortho-nitrophenol
- Assi, Navid, Mohammadi, Ali, Sadr Manuchehri, Q, Walker, Roderick B
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
Synthesis and Photophysical Investigation of Tetraazaporphyrin Substituted with Aggregation‐Induced Emission (AIE) Active Moieties
- Tasso, Thiago T, Furuyama, Taniyuki, Mack, John, Nyokong, Tebello, Kobayashi, Nagao
- Authors: Tasso, Thiago T , Furuyama, Taniyuki , Mack, John , Nyokong, Tebello , Kobayashi, Nagao
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193553 , vital:45346 , xlink:href="https://doi.org/10.1002/ejic.201500726"
- Description: The synthesis and characterization of free-base and ZnII tetraazaporphyrins with tetraphenylethylene (TPE) or diphenylphenanthrene (DPP) moieties that are known to be aggregation-induced emission (AIE) active is reported. The optical spectra contain the characteristic Q and B absorption bands of Gouterman's four-orbital model and a broad envelope of weaker charge-transfer bands in the 450–600 nm region. The observed fluorescence emission lies beyond 670 nm and originates exclusively from the decay of the S1 state of the macrocycle, regardless of the excitation wavelength used. Theoretical calculations provide further evidence of strong electronic communication between the peripheral TPE or DPP moieties and the central ring. The ZnII complexes were found to have relatively high singlet-oxygen quantum yields.
- Full Text:
- Date Issued: 2015
- Authors: Tasso, Thiago T , Furuyama, Taniyuki , Mack, John , Nyokong, Tebello , Kobayashi, Nagao
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193553 , vital:45346 , xlink:href="https://doi.org/10.1002/ejic.201500726"
- Description: The synthesis and characterization of free-base and ZnII tetraazaporphyrins with tetraphenylethylene (TPE) or diphenylphenanthrene (DPP) moieties that are known to be aggregation-induced emission (AIE) active is reported. The optical spectra contain the characteristic Q and B absorption bands of Gouterman's four-orbital model and a broad envelope of weaker charge-transfer bands in the 450–600 nm region. The observed fluorescence emission lies beyond 670 nm and originates exclusively from the decay of the S1 state of the macrocycle, regardless of the excitation wavelength used. Theoretical calculations provide further evidence of strong electronic communication between the peripheral TPE or DPP moieties and the central ring. The ZnII complexes were found to have relatively high singlet-oxygen quantum yields.
- Full Text:
- Date Issued: 2015
Synthesis and photophysical properties of nanocomposites of aluminum tetrasulfonated phthalocyanine covalently linked to glutathione capped CdTe/CdS/ZnS quantum dots
- Oluwole, David O, Britton, Jonathan, Mashazi, Philani N, Nyokong, Tebello
- Authors: Oluwole, David O , Britton, Jonathan , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241379 , vital:50934 , xlink:href="https://doi.org/10.1016/j.synthmet.2015.04.015"
- Description: Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was covalently linked with different sizes of glutathione capped CdTe/CdS/ZnS quantum dots (QDs). The photophysical and Förster resonance energy transfer (FRET) properties of the nanoconjugates were investigated. The CdTe/CdS/ZnS(6.3) nanocomposite showed the highest enhancement in its photophysical properties while (CdTe/CdS/ZnS(3.2) nanocomposite showed the least. Highest FRET efficiency was observed in the linked CdTe/CdS/ZnS(6.3) nanocomposites at 93%. Hence, the combination of CdTe/CdS/ZnS with ClAlTSPc exhibited excellent photophysical properties.
- Full Text:
- Date Issued: 2015
- Authors: Oluwole, David O , Britton, Jonathan , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241379 , vital:50934 , xlink:href="https://doi.org/10.1016/j.synthmet.2015.04.015"
- Description: Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was covalently linked with different sizes of glutathione capped CdTe/CdS/ZnS quantum dots (QDs). The photophysical and Förster resonance energy transfer (FRET) properties of the nanoconjugates were investigated. The CdTe/CdS/ZnS(6.3) nanocomposite showed the highest enhancement in its photophysical properties while (CdTe/CdS/ZnS(3.2) nanocomposite showed the least. Highest FRET efficiency was observed in the linked CdTe/CdS/ZnS(6.3) nanocomposites at 93%. Hence, the combination of CdTe/CdS/ZnS with ClAlTSPc exhibited excellent photophysical properties.
- Full Text:
- Date Issued: 2015
Synthesis of single-walled carbon nanotubes by the pyrolysis of a compression activated iron (II) phthalocyanine/phthalocyanine metal-free derivative/ferric acetate mixture
- Mugadza, Tawanda, Antunes, Edith M, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Antunes, Edith M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189729 , vital:44926 , xlink:href="https://doi.org/10.1007/s12039-015-0886-y"
- Description: This paper reports on the synthesis of single walled carbon nanotubes (SWCNTs) from an activated mixture of iron (II) phthalocyanine, its metal-free derivative and ferric acetate. The powdered mixture was activated by compression into a tablet by applying a force of 300 kN, followed by re-grinding into powder and heating it to high temperatures (1000°C). The activation by compression resulted in more than 50% debundling of SWCNTs as judged by transition electron microscopy. Acid functionalization of the SWCNTs was confirmed by the increase in the D:G ratio from 0.56 to 0.87 in the Raman spectra and the observation of an average of one carboxylic acid group per 13 carbon atoms from thermogravimetric analysis (TGA). TGA also showed that the initial decomposition temperatures for the activated and non-activated mixtures to be 205°C and 245°C, respectively. Hence, activation leads to the lowering of the pyrolysis temperature of the phthalocyanines. X-ray diffraction, electronic absorption and Fourier transform infrared spectra were also employed to characterize the SWCNT.
- Full Text:
- Date Issued: 2015
- Authors: Mugadza, Tawanda , Antunes, Edith M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189729 , vital:44926 , xlink:href="https://doi.org/10.1007/s12039-015-0886-y"
- Description: This paper reports on the synthesis of single walled carbon nanotubes (SWCNTs) from an activated mixture of iron (II) phthalocyanine, its metal-free derivative and ferric acetate. The powdered mixture was activated by compression into a tablet by applying a force of 300 kN, followed by re-grinding into powder and heating it to high temperatures (1000°C). The activation by compression resulted in more than 50% debundling of SWCNTs as judged by transition electron microscopy. Acid functionalization of the SWCNTs was confirmed by the increase in the D:G ratio from 0.56 to 0.87 in the Raman spectra and the observation of an average of one carboxylic acid group per 13 carbon atoms from thermogravimetric analysis (TGA). TGA also showed that the initial decomposition temperatures for the activated and non-activated mixtures to be 205°C and 245°C, respectively. Hence, activation leads to the lowering of the pyrolysis temperature of the phthalocyanines. X-ray diffraction, electronic absorption and Fourier transform infrared spectra were also employed to characterize the SWCNT.
- Full Text:
- Date Issued: 2015
Synthesis, characterization and photophysical properties of an acenaphthalene fused-ring-expanded NIR absorbing aza-BODIPY dye
- Majumdar, Poulomi, Mack, John, Nyokong, Tebello
- Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189763 , vital:44929 , xlink:href="https://doi.org/10.1039/C5RA14916A"
- Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY.
- Full Text:
- Date Issued: 2015
- Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189763 , vital:44929 , xlink:href="https://doi.org/10.1039/C5RA14916A"
- Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY.
- Full Text:
- Date Issued: 2015
Synthesis, photophysical and nonlinear optical behavior of neodymium based trisphthalocyanine
- Sekhosana, Kutloana E, Amuhaya, Edith, Khene, Samson M, Nyokong, Tebello
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Khene, Samson M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241412 , vital:50937 , xlink:href="https://doi.org/10.1016/j.ica.2014.11.029"
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex.
- Full Text:
- Date Issued: 2015
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Khene, Samson M , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241412 , vital:50937 , xlink:href="https://doi.org/10.1016/j.ica.2014.11.029"
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex.
- Full Text:
- Date Issued: 2015
Synthesis, photophysics and photochemistry of phthalocyanine-ɛ-polylysine conjugates in the presence of metal nanoparticles against Staphylococcus aureus
- Nombona, Nolwazi, Antunes, Edith M, Chidawanyika, Wadzanai J U, Kleyi, Phumelele, Tshentu, Zenixole, Nyokong, Tebello
- Authors: Nombona, Nolwazi , Antunes, Edith M , Chidawanyika, Wadzanai J U , Kleyi, Phumelele , Tshentu, Zenixole , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244439 , vital:51257 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: This work reports on the photodynamic activity of Zn phthalocyanine-ɛ-polylysine conjugates in the presence of gold and silver nanoparticles (NPs) towards the inactivation of Staphylococcus aureus (S. aureus). The conjugates showed high photoinactivation with ∼6% growth at a drug dose of 3 μM and fluence of 39.6 mW/cm2 for 10 min irradiation time in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC50) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The MIC50 was lowest for the conjugate of 3 with ɛ-polylysine at concentrations of less than 0.0058 μM in the presence of AgNPs. The lethal photosensitization of microorganisms has emerged as a promising treatment since bacteria have reduced possibilities of developing resistance to photodynamic therapy.
- Full Text:
- Date Issued: 2015
- Authors: Nombona, Nolwazi , Antunes, Edith M , Chidawanyika, Wadzanai J U , Kleyi, Phumelele , Tshentu, Zenixole , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244439 , vital:51257 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: This work reports on the photodynamic activity of Zn phthalocyanine-ɛ-polylysine conjugates in the presence of gold and silver nanoparticles (NPs) towards the inactivation of Staphylococcus aureus (S. aureus). The conjugates showed high photoinactivation with ∼6% growth at a drug dose of 3 μM and fluence of 39.6 mW/cm2 for 10 min irradiation time in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC50) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The MIC50 was lowest for the conjugate of 3 with ɛ-polylysine at concentrations of less than 0.0058 μM in the presence of AgNPs. The lethal photosensitization of microorganisms has emerged as a promising treatment since bacteria have reduced possibilities of developing resistance to photodynamic therapy.
- Full Text:
- Date Issued: 2015
The benefits from and barriers to participation in civic environmental organisations in South Africa
- Higgins, Olivia, Shackleton, Charlie M
- Authors: Higgins, Olivia , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180813 , vital:43648 , xlink:href="https://doi.org/10.1007/s10531-015-0924-6"
- Description: With growing global public awareness of a wide range of conservation and environmental issues, environmental volunteerism is increasing. In order to attract and retain volunteers, it is useful to understand what benefits they hope for as well as the barriers that hinder their participation. Here we examine the benefits from and barriers to participation in 26 conservation and environmental civic organisations in South Africa, categorised by their primary mission as botanical, wildlife or green. Questionnaires were sent to volunteers on the mailing list of each civic organisation (and 66 responses received), supplemented with direct interviews with key staff and five focus group discussions. There were differences in the perception of benefits obtained and barriers experienced by volunteers between the three groups. Respondents from botanical and green civic organisations rated enjoyment of the task as the primary benefit, whereas the most common response amongst wildlife organisation volunteers was a higher level of life satisfaction. Lack of time was a major barrier across all groups, whilst lack of communication between organisers and volunteers was mentioned frequently by volunteers in wildlife and green organisations. The mean number of hours offered per volunteer was significantly higher amongst wildlife organisations than either botanical or green ones, but for all three, the value of volunteer contributions was, at several millions of rand annually, substantial. There was no relationship between the number of perceived benefits and the number of hours volunteered. This study indicates that motivations and barriers differ amongst volunteers, which is important to acknowledge in attracting and optimising the contributions of conservation and environmental volunteers.
- Full Text:
- Date Issued: 2015
The benefits from and barriers to participation in civic environmental organisations in South Africa
- Authors: Higgins, Olivia , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180813 , vital:43648 , xlink:href="https://doi.org/10.1007/s10531-015-0924-6"
- Description: With growing global public awareness of a wide range of conservation and environmental issues, environmental volunteerism is increasing. In order to attract and retain volunteers, it is useful to understand what benefits they hope for as well as the barriers that hinder their participation. Here we examine the benefits from and barriers to participation in 26 conservation and environmental civic organisations in South Africa, categorised by their primary mission as botanical, wildlife or green. Questionnaires were sent to volunteers on the mailing list of each civic organisation (and 66 responses received), supplemented with direct interviews with key staff and five focus group discussions. There were differences in the perception of benefits obtained and barriers experienced by volunteers between the three groups. Respondents from botanical and green civic organisations rated enjoyment of the task as the primary benefit, whereas the most common response amongst wildlife organisation volunteers was a higher level of life satisfaction. Lack of time was a major barrier across all groups, whilst lack of communication between organisers and volunteers was mentioned frequently by volunteers in wildlife and green organisations. The mean number of hours offered per volunteer was significantly higher amongst wildlife organisations than either botanical or green ones, but for all three, the value of volunteer contributions was, at several millions of rand annually, substantial. There was no relationship between the number of perceived benefits and the number of hours volunteered. This study indicates that motivations and barriers differ amongst volunteers, which is important to acknowledge in attracting and optimising the contributions of conservation and environmental volunteers.
- Full Text:
- Date Issued: 2015
The design and evaluation of targeted patient-centred health information to improve knowledge and behavioural outcomes in tuberculosis patients with limited literacy
- Authors: Patel, Sonal
- Date: 2015
- Subjects: Tuberculosis Patients , Health literacy , Patient education , Communication in medicine , Picture-writing
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194071 , vital:45420 , DOI 10.21504/10962/194071
- Description: South Africa carries a significant TB burden as evidenced in the 2013 statistics which report 450 000 new active TB cases and 890 000 TB-related mortalities. For successful treatment outcomes, 90% adherence is necessary, but many patients prematurely discontinue treatment due to poor knowledge and understanding of their complex TB medicines. Patient education is pivotal in improving knowledge, health literacy and behavioural outcomes such as health information seeking, self-efficacy and adherence. In the under-resourced South African healthcare system, time and capacity to adequately counsel patients are limited. The value of written medicine information (WMI) to supplement the verbal information provided by healthcare professionals (HCPs) has been widely investigated but minimal South African research is available. Current WMI distributed in South Africa is mainly generated by pharmaceutical manufacturers and is complex, incomprehensible and undesirable to patients. TB-related WMI focuses mainly on the disease, with little information relating to TB medicines and their use. The overall aim of this project was to improve patient knowledge about their TB medicines through the use of a simple illustrated patient information leaflet (PIL). Objectives to achieve this aim included: investigation of the medicine information seeking behaviour (MISB) of long term patients attending public health sector facilities; the development and validation of a medicine literacy test (MLT) to identify patients with limited health literacy requiring additional support and counselling; the development and evaluation of a patient-centred illustrated PIL for first-line TB treatment; the assessment of self-efficacy and adherence using modified versions of the HIV Treatment Adherence Self-Efficacy Scale (HIV-ASES) and Morisky 8-item Medicine Adherence Scale (MMAS-8), respectively, and the investigation of the impact of the PIL on patient knowledge and these health-related behaviours. Six focus group discussions (FGDs) conducted in 34 isiXhosa-speaking patients with limited formal education taking long-term treatment explored themes related to information needs, information-seeking practices and awareness of and ability to utilize information sources. Codes were analysed and potential themes and subthemes were identified and refined. The findings of this study reflected a passive, disempowered patient due to both patient-related and systemic healthcare factors. Poor awareness of information sources, lack of health-related knowledge, stigma and lack of awareness of the importance of appropriate medicine-related knowledge contributed to a lack of information-seeking practice. Patients neither asked questions nor were encouraged to do so. All expressed an unmet need for information and a desire for receiving relevant, appropriate, written medicine-related information. Feedback from this phase of the study was used to inform the development of the targeted patientcentred PIL. A double-sided A4 PIL containing information about TB medicines was designed giving careful consideration to content, format and layout features. Twenty five pictograms were designed through a rigorous, iterative design process and were included in the PIL that was evaluated in a randomised control trial (RCT) conducted amongst 120 TB patients attending a high burden TB clinic in South Africa. Interviews were conducted in either isiXhosa or Afrikaans via a trained interpreter. Patients were randomly allocated to either a control (standard care) or an experimental group (standard care plus brief counselling using the PIL). Two interviews were conducted using a prepared questionnaire; one at baseline followed by a 4-week follow-up. Baseline data included demographics, medicine literacy test, health information sources, knowledge of TB medicines, self-reported adherence and self-efficacy. Data collected at the 4-week follow-up interview included TB knowledge, self-reported adherence, self-efficacy, opinion of TB medicine information and interpretation of pictograms. Data were analysed using t-test, correlations, chi-square and ANOVA tests at a 0.05 level of significance. The PIL was successful in improving patient knowledge of the disease, TB medicine-taking, side effects, drug-resistant TB and HIV and TB co-infection. At baseline, there was no significant difference in the overall mean percentage knowledge score between the control and experimental groups (p=0.074). At follow-up, the percentage knowledge score for the experimental group increased significantly from 59.0% to 84.6% (p<0.001) and showed a significantly higher score than the control group (p<0.001), displaying evidence of the impact of the PIL as a counselling tool on patient knowledge. The PIL generated a highly positive response in the experimental group who indicated that they had referred to the leaflet over the last month and that it had played an important role in improving their TB medicine-related knowledge. This was reflected in the experimental group knowledge score of greater than 80% for almost three quarters of the patients whereas only 14% in the control group achieved this score. Patients appreciated the inclusion of pictograms and strongly felt that they helped them to recall and understand the textual PIL content. The study found that patients want side effect information and, interestingly, did not perceive the presentation of side effects in pictorial form to constitute a risk factor for nonadherence. Use of the illustrated PIL (experimental group) resulted in a significant improvement in patient self-efficacy (p=0.002), but showed no effect on self-reported adherence (p=0.563). Neither self-efficacy nor adherence was influenced by gender, age or education. An education effect on knowledge was only observed in the control group at baseline. The newly developed MLT was shown to be a valid and reliable tool and a moderate, positive and significant correlation was noted between the MLT score and baseline TB medicine-related knowledge in both the control and experimental groups. As there is a paucity of studies investigating the influence of take-home written leaflets on TB medicine knowledge and on patient behaviour, this study represents a significant knowledge contribution. It is the first study to report the development and evaluation of a patient-centred PIL to address the dearth of available TB medicine information. The use of targeted user-friendly, illustrated information leaflets can be a valuable counselling aid to improve patient knowledge and self-efficacy, particularly among patients with limited literacy. However, careful consideration of the design and content, with input from the endusers at all stages of the process, will optimise its effectiveness. The proposed framework for the development and implementation of patient-centred health and medicines information in a developing country context presented in this thesis could be used as a theoretical basis for informing the development of effective information materials targeting other disease states. Local patients taking TB medicines identified nurses, WMI and media as their current sources of information but they expressed a strong desire to know more about their treatment. Targeted public health interventions that focus on medicine-taking information and behaviours and encourage patients to adopt a more active, questioning role in health consultations could improve health literacy and empower patients in their medicine-taking practices. , Thesis (PhD) -- Faculty of Pharmacy, Pharmacy, 2015
- Full Text:
- Date Issued: 2015
- Authors: Patel, Sonal
- Date: 2015
- Subjects: Tuberculosis Patients , Health literacy , Patient education , Communication in medicine , Picture-writing
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194071 , vital:45420 , DOI 10.21504/10962/194071
- Description: South Africa carries a significant TB burden as evidenced in the 2013 statistics which report 450 000 new active TB cases and 890 000 TB-related mortalities. For successful treatment outcomes, 90% adherence is necessary, but many patients prematurely discontinue treatment due to poor knowledge and understanding of their complex TB medicines. Patient education is pivotal in improving knowledge, health literacy and behavioural outcomes such as health information seeking, self-efficacy and adherence. In the under-resourced South African healthcare system, time and capacity to adequately counsel patients are limited. The value of written medicine information (WMI) to supplement the verbal information provided by healthcare professionals (HCPs) has been widely investigated but minimal South African research is available. Current WMI distributed in South Africa is mainly generated by pharmaceutical manufacturers and is complex, incomprehensible and undesirable to patients. TB-related WMI focuses mainly on the disease, with little information relating to TB medicines and their use. The overall aim of this project was to improve patient knowledge about their TB medicines through the use of a simple illustrated patient information leaflet (PIL). Objectives to achieve this aim included: investigation of the medicine information seeking behaviour (MISB) of long term patients attending public health sector facilities; the development and validation of a medicine literacy test (MLT) to identify patients with limited health literacy requiring additional support and counselling; the development and evaluation of a patient-centred illustrated PIL for first-line TB treatment; the assessment of self-efficacy and adherence using modified versions of the HIV Treatment Adherence Self-Efficacy Scale (HIV-ASES) and Morisky 8-item Medicine Adherence Scale (MMAS-8), respectively, and the investigation of the impact of the PIL on patient knowledge and these health-related behaviours. Six focus group discussions (FGDs) conducted in 34 isiXhosa-speaking patients with limited formal education taking long-term treatment explored themes related to information needs, information-seeking practices and awareness of and ability to utilize information sources. Codes were analysed and potential themes and subthemes were identified and refined. The findings of this study reflected a passive, disempowered patient due to both patient-related and systemic healthcare factors. Poor awareness of information sources, lack of health-related knowledge, stigma and lack of awareness of the importance of appropriate medicine-related knowledge contributed to a lack of information-seeking practice. Patients neither asked questions nor were encouraged to do so. All expressed an unmet need for information and a desire for receiving relevant, appropriate, written medicine-related information. Feedback from this phase of the study was used to inform the development of the targeted patientcentred PIL. A double-sided A4 PIL containing information about TB medicines was designed giving careful consideration to content, format and layout features. Twenty five pictograms were designed through a rigorous, iterative design process and were included in the PIL that was evaluated in a randomised control trial (RCT) conducted amongst 120 TB patients attending a high burden TB clinic in South Africa. Interviews were conducted in either isiXhosa or Afrikaans via a trained interpreter. Patients were randomly allocated to either a control (standard care) or an experimental group (standard care plus brief counselling using the PIL). Two interviews were conducted using a prepared questionnaire; one at baseline followed by a 4-week follow-up. Baseline data included demographics, medicine literacy test, health information sources, knowledge of TB medicines, self-reported adherence and self-efficacy. Data collected at the 4-week follow-up interview included TB knowledge, self-reported adherence, self-efficacy, opinion of TB medicine information and interpretation of pictograms. Data were analysed using t-test, correlations, chi-square and ANOVA tests at a 0.05 level of significance. The PIL was successful in improving patient knowledge of the disease, TB medicine-taking, side effects, drug-resistant TB and HIV and TB co-infection. At baseline, there was no significant difference in the overall mean percentage knowledge score between the control and experimental groups (p=0.074). At follow-up, the percentage knowledge score for the experimental group increased significantly from 59.0% to 84.6% (p<0.001) and showed a significantly higher score than the control group (p<0.001), displaying evidence of the impact of the PIL as a counselling tool on patient knowledge. The PIL generated a highly positive response in the experimental group who indicated that they had referred to the leaflet over the last month and that it had played an important role in improving their TB medicine-related knowledge. This was reflected in the experimental group knowledge score of greater than 80% for almost three quarters of the patients whereas only 14% in the control group achieved this score. Patients appreciated the inclusion of pictograms and strongly felt that they helped them to recall and understand the textual PIL content. The study found that patients want side effect information and, interestingly, did not perceive the presentation of side effects in pictorial form to constitute a risk factor for nonadherence. Use of the illustrated PIL (experimental group) resulted in a significant improvement in patient self-efficacy (p=0.002), but showed no effect on self-reported adherence (p=0.563). Neither self-efficacy nor adherence was influenced by gender, age or education. An education effect on knowledge was only observed in the control group at baseline. The newly developed MLT was shown to be a valid and reliable tool and a moderate, positive and significant correlation was noted between the MLT score and baseline TB medicine-related knowledge in both the control and experimental groups. As there is a paucity of studies investigating the influence of take-home written leaflets on TB medicine knowledge and on patient behaviour, this study represents a significant knowledge contribution. It is the first study to report the development and evaluation of a patient-centred PIL to address the dearth of available TB medicine information. The use of targeted user-friendly, illustrated information leaflets can be a valuable counselling aid to improve patient knowledge and self-efficacy, particularly among patients with limited literacy. However, careful consideration of the design and content, with input from the endusers at all stages of the process, will optimise its effectiveness. The proposed framework for the development and implementation of patient-centred health and medicines information in a developing country context presented in this thesis could be used as a theoretical basis for informing the development of effective information materials targeting other disease states. Local patients taking TB medicines identified nurses, WMI and media as their current sources of information but they expressed a strong desire to know more about their treatment. Targeted public health interventions that focus on medicine-taking information and behaviours and encourage patients to adopt a more active, questioning role in health consultations could improve health literacy and empower patients in their medicine-taking practices. , Thesis (PhD) -- Faculty of Pharmacy, Pharmacy, 2015
- Full Text:
- Date Issued: 2015
The development of palladium (II)-specific amine-functionalized silica-based microparticles
- Fayemi, Omolola E, Ogunlaja, Adeniyi S, Antunes, Edith M, Nyokong, Tebello, Tshentu, Zenixole R
- Authors: Fayemi, Omolola E , Ogunlaja, Adeniyi S , Antunes, Edith M , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241083 , vital:50903 , xlink:href="https://doi.org/10.1080/01496395.2014.978017"
- Description: The adsorption and separation of platinum(IV) and palladium(II) chlorido species ([PtCl6]2− and [PdCl4]2−) on silica-based microparticles functionalized with ammonium centers based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetriamine (TETA) and tris-(2-aminoethyl)amine (TAEA) were investigated. The functionalized sorbent materials were characterized using SEM, XPS, BET, and FTIR. The sorbents were used in the batch and column study for adsorption and selective separation of [PtCl62− and PdCl4]2−. The adsorption model for both [PtCl6]2− and [PdCl4]2− on the different sorbent materials fitted the Freundlich isotherm with R2 values > 0.99. The S-TETA sorbent material was palladium(II) specific. Pd(II) loaded on the silica column was recovered using 3% m/v thiourea solution as the eluting agent. Separation of platinum and palladium was achieved by selective stripping of [PtCl6]2− with 0.5 M of NaClO4 in 1.0 M HCl while Pd(II) was eluted with 0.5 M thiourea in 1.0 M HCl. The separation of palladium (Pd) from a mixture containing platinum (Pt), iridium (Ir), and rhodium (Rh) was successful on silica functionalized with triethylenetriamine (TETA) showing specificity for palladium(II) and a loading capacity of 0.27 mg/g. S-TETA showed potential for use in the recovery of palladium from platinum group metals such as from solutions of worn out automobile emission control catalytic convertors and other secondary sources.
- Full Text:
- Date Issued: 2015
- Authors: Fayemi, Omolola E , Ogunlaja, Adeniyi S , Antunes, Edith M , Nyokong, Tebello , Tshentu, Zenixole R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241083 , vital:50903 , xlink:href="https://doi.org/10.1080/01496395.2014.978017"
- Description: The adsorption and separation of platinum(IV) and palladium(II) chlorido species ([PtCl6]2− and [PdCl4]2−) on silica-based microparticles functionalized with ammonium centers based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetriamine (TETA) and tris-(2-aminoethyl)amine (TAEA) were investigated. The functionalized sorbent materials were characterized using SEM, XPS, BET, and FTIR. The sorbents were used in the batch and column study for adsorption and selective separation of [PtCl62− and PdCl4]2−. The adsorption model for both [PtCl6]2− and [PdCl4]2− on the different sorbent materials fitted the Freundlich isotherm with R2 values > 0.99. The S-TETA sorbent material was palladium(II) specific. Pd(II) loaded on the silica column was recovered using 3% m/v thiourea solution as the eluting agent. Separation of platinum and palladium was achieved by selective stripping of [PtCl6]2− with 0.5 M of NaClO4 in 1.0 M HCl while Pd(II) was eluted with 0.5 M thiourea in 1.0 M HCl. The separation of palladium (Pd) from a mixture containing platinum (Pt), iridium (Ir), and rhodium (Rh) was successful on silica functionalized with triethylenetriamine (TETA) showing specificity for palladium(II) and a loading capacity of 0.27 mg/g. S-TETA showed potential for use in the recovery of palladium from platinum group metals such as from solutions of worn out automobile emission control catalytic convertors and other secondary sources.
- Full Text:
- Date Issued: 2015
The development visions and attitudes towards urban forestry of officials responsible for greening in South African towns
- Gwedla, Nanamhla, Shackleton, Charlie M
- Authors: Gwedla, Nanamhla , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180856 , vital:43651 , xlink:href="https://doi.org/10.1016/j.landusepol.2014.07.004"
- Description: The planting and maintenance of trees in public areas of South African towns is the responsibility of local municipalities. Therefore, it is necessary to appreciate the visions and attitudes of municipal officials and decision-makers in charge of such activities for an understanding of the distribution and abundance of trees along streets and in urban green spaces. We hypothesised that the town size and relative wealth and current extent of trees in public places would influence the visions of such officials. We therefore conducted 24 semi-structured interviews with the officials responsible for urban tree planting in 24 towns in the Eastern Cape province, whilst also assessing the abundance of street trees via GIS counts. The density of street trees was variable, ranging from 0.5 to 9.5 trees/ha. There were significantly positive relationships between town size, relative wealth measures and street tree density. Several of the managers did not include environmental issues or trees in vision of the future for their town, although most did. There was no relationship between the managers’ visions for the future and attitudes and current street tree density. Most of the managers experienced several constraints in trying to implement their vision, notably a lack of funds for urban forestry, limited space for tree planting in low-cost housing developments, vandalism, and lack of skilled personnel.
- Full Text:
- Date Issued: 2015
- Authors: Gwedla, Nanamhla , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180856 , vital:43651 , xlink:href="https://doi.org/10.1016/j.landusepol.2014.07.004"
- Description: The planting and maintenance of trees in public areas of South African towns is the responsibility of local municipalities. Therefore, it is necessary to appreciate the visions and attitudes of municipal officials and decision-makers in charge of such activities for an understanding of the distribution and abundance of trees along streets and in urban green spaces. We hypothesised that the town size and relative wealth and current extent of trees in public places would influence the visions of such officials. We therefore conducted 24 semi-structured interviews with the officials responsible for urban tree planting in 24 towns in the Eastern Cape province, whilst also assessing the abundance of street trees via GIS counts. The density of street trees was variable, ranging from 0.5 to 9.5 trees/ha. There were significantly positive relationships between town size, relative wealth measures and street tree density. Several of the managers did not include environmental issues or trees in vision of the future for their town, although most did. There was no relationship between the managers’ visions for the future and attitudes and current street tree density. Most of the managers experienced several constraints in trying to implement their vision, notably a lack of funds for urban forestry, limited space for tree planting in low-cost housing developments, vandalism, and lack of skilled personnel.
- Full Text:
- Date Issued: 2015
The direct-use value of urban tree non-timber forest products to household income in poorer suburbs in South African towns
- Kaoma, Humphrey, Shackleton, Charlie M
- Authors: Kaoma, Humphrey , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180778 , vital:43645 , xlink:href="https://doi.org/10.1016/j.forpol.2015.08.005"
- Description: Valuation of the contribution of non-timber forest products (NTFPs) to household incomes has been well researched in the rural and remote areas of the developing world. In comparison, there has been little investigation of the contribution of NTFPs in urban areas and amongst the urban poor. This paper reports results from a survey of 450 households across three towns on the use and value of tree NTFPs collected by households in the poorer areas from their own homesteads, open spaces within towns and at the urban periphery. Collection (and purchase) of tree NTFPs was widespread, especially of firewood and fruits. The ratio collected from homesteads relative to other urban spaces differed between products and the amount required. Overall, approximately 20% of household income was derived from urban tree NTFPs. The highest contribution (33%) was amongst the poorest sectors represented by mostly recent migrants to towns who were living in informal settlements whilst trying to establish a foothold in the urban economy. In the formal housing areas the contribution was at least 14%, which has been overlooked by standard income surveys in urban areas.
- Full Text:
- Date Issued: 2015
- Authors: Kaoma, Humphrey , Shackleton, Charlie M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180778 , vital:43645 , xlink:href="https://doi.org/10.1016/j.forpol.2015.08.005"
- Description: Valuation of the contribution of non-timber forest products (NTFPs) to household incomes has been well researched in the rural and remote areas of the developing world. In comparison, there has been little investigation of the contribution of NTFPs in urban areas and amongst the urban poor. This paper reports results from a survey of 450 households across three towns on the use and value of tree NTFPs collected by households in the poorer areas from their own homesteads, open spaces within towns and at the urban periphery. Collection (and purchase) of tree NTFPs was widespread, especially of firewood and fruits. The ratio collected from homesteads relative to other urban spaces differed between products and the amount required. Overall, approximately 20% of household income was derived from urban tree NTFPs. The highest contribution (33%) was amongst the poorest sectors represented by mostly recent migrants to towns who were living in informal settlements whilst trying to establish a foothold in the urban economy. In the formal housing areas the contribution was at least 14%, which has been overlooked by standard income surveys in urban areas.
- Full Text:
- Date Issued: 2015
The effect of ascorbic acid on the photophysical properties and photodynamic therapy activities of zinc phthalocyanine-single walled carbon nanotube conjugate on MCF-7 cancer cells
- Ogbodu, Racheal O, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189066 , vital:44813 , xlink:href="https://doi.org/10.1016/j.saa.2015.06.063"
- Description: Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π–π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents.
- Full Text:
- Date Issued: 2015
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189066 , vital:44813 , xlink:href="https://doi.org/10.1016/j.saa.2015.06.063"
- Description: Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π–π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents.
- Full Text:
- Date Issued: 2015
The effect of long-distance transportation on the fitness of irradiated false codling Moth (Lepidoptera: Tortricidae) for use in a sterile insect release program
- Nepgen, Eugene S, Hill, Martin P, Moore, Sean D
- Authors: Nepgen, Eugene S , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423835 , vital:72098 , xlink:href="https://doi.org/10.1093/jee/tov246"
- Description: The effect of cold immobilization and long-distance transport of irradiated Thaumatotibia leucotreta (Meyrick) on the flight ability of male (?) and female (/) moths, the longevity of male and female moths, and the realized fecundity of mating pairs CIM (chilled irradiated moths) / CIM?, CIM/ NIP (nonirradiated pupae) ?, NIP/ CIM?, and NIP/ NIP? was examined to improve application of the sterile insect technique (SIT). Adult moths treated with 150 Gy of gamma radiation were immobilized with cold temperature between 4 and 6C inside a polyurethane cooler box and transported for 12 h by road from Citrusdal, Western Cape Province, to Addo, Eastern Cape Province. Nonirradiated moths were transported as pupae inside a cardboard tray and removed by hand after which male and female pupae were separated and placed inside containers for eclosion. Male and female moths were individually placed inside petri dishes to determine longevity or paired with irradiated and nonirradiated counterparts to evaluate realized fecundity before incubation in 100% darkness at 25C and 75% relative humidity. Flight tests were conducted indoors at 25C by release of individual moths per hand. A significant decrease in flight ability and longevity of irradiated false codling moth was found after handling, cold immobilization, and transport, although critically, realized fecundity was not affected. Because of the impact of long-distance transport on quality of the released insects as well as the efficacy of SIT, comprehensive protocols for this critical step in the process need to be developed for a pestiferous insect with phytosanitary status such as false codling moth.
- Full Text:
- Date Issued: 2015
- Authors: Nepgen, Eugene S , Hill, Martin P , Moore, Sean D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423835 , vital:72098 , xlink:href="https://doi.org/10.1093/jee/tov246"
- Description: The effect of cold immobilization and long-distance transport of irradiated Thaumatotibia leucotreta (Meyrick) on the flight ability of male (?) and female (/) moths, the longevity of male and female moths, and the realized fecundity of mating pairs CIM (chilled irradiated moths) / CIM?, CIM/ NIP (nonirradiated pupae) ?, NIP/ CIM?, and NIP/ NIP? was examined to improve application of the sterile insect technique (SIT). Adult moths treated with 150 Gy of gamma radiation were immobilized with cold temperature between 4 and 6C inside a polyurethane cooler box and transported for 12 h by road from Citrusdal, Western Cape Province, to Addo, Eastern Cape Province. Nonirradiated moths were transported as pupae inside a cardboard tray and removed by hand after which male and female pupae were separated and placed inside containers for eclosion. Male and female moths were individually placed inside petri dishes to determine longevity or paired with irradiated and nonirradiated counterparts to evaluate realized fecundity before incubation in 100% darkness at 25C and 75% relative humidity. Flight tests were conducted indoors at 25C by release of individual moths per hand. A significant decrease in flight ability and longevity of irradiated false codling moth was found after handling, cold immobilization, and transport, although critically, realized fecundity was not affected. Because of the impact of long-distance transport on quality of the released insects as well as the efficacy of SIT, comprehensive protocols for this critical step in the process need to be developed for a pestiferous insect with phytosanitary status such as false codling moth.
- Full Text:
- Date Issued: 2015
The effects of gold coated and uncoated zinc oxide nanohexagons on the photophysicochemical properties of the low symmetry zinc phthalocyanine
- D'Souza, Sarah, Ogbodu, Rachael, Nyokong, Tebello
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
- Full Text:
- Date Issued: 2015
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
- Full Text:
- Date Issued: 2015
The impact of globalization on economic growth in South Africa
- Authors: Maronga, Vimbai Linah
- Date: 2015
- Subjects: Economic development -- South Africa , International economic integration , International trade
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25861 , vital:64552
- Description: The dissertation investigated the impact of globalization on the economic growth of South Africa using annual South African data covering the period 1975 to 2011. The study used Johansen cointegration and vector error correction model to determine the impact of globalization on economic growth in South Africa. The VECM model with South African variables was specified and used to assess the effects of globalization on South Africa’s economic growth. Results of the study suggested that the South African economic growth was negatively impacted by globalization in the long run. Using the results conclusions and policy recommendations were made using these results. , Thesis (MCom) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015
- Authors: Maronga, Vimbai Linah
- Date: 2015
- Subjects: Economic development -- South Africa , International economic integration , International trade
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25861 , vital:64552
- Description: The dissertation investigated the impact of globalization on the economic growth of South Africa using annual South African data covering the period 1975 to 2011. The study used Johansen cointegration and vector error correction model to determine the impact of globalization on economic growth in South Africa. The VECM model with South African variables was specified and used to assess the effects of globalization on South Africa’s economic growth. Results of the study suggested that the South African economic growth was negatively impacted by globalization in the long run. Using the results conclusions and policy recommendations were made using these results. , Thesis (MCom) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015
The impact of unguided animal husbandry on the peripheral and landscape elements: the case of Alice
- Chungag, Anye https://orcid.org/0000-0002-2308-9410
- Authors: Chungag, Anye https://orcid.org/0000-0002-2308-9410
- Date: 2015
- Subjects: Livestock , Animal culture , Animal culture -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19511 , vital:43134
- Description: This study is based on Unguided Animal Husbandry as practiced in the town of Alice and its surrounding locations. It underscores the fact that though cattle are domesticated animals, they are still migratory in character. Their migratory tendency is prompted by the need of food and water and sometimes convenient rest positions. The search for food, water and rest may lead cattle to travel for many kilometres away from enclosure. This movement allows them to establish eating and drinking preferences and locations which become habitual, hence tracks develop along these paths which greatly compromise the soil, water and vegetation quality of the landscape. This study identifies such tracks and investigates the impact of cattle movement on soil physical properties and vegetation characteristics. However all this is against the back drop of the open access land regime; a mode of exploiting common property to which all have equal rights. It is a system of land management that comes with inherent challenges. Amongst them a selfish inclination of taking decisions that is motivated by egoistic interests and utmost personal gain. Secondly no thought is given to management and sustainability, subjecting common property to Haddins (1968) philosophy ‘The tragedy of the commons’. The results of the study show that when cattle is left to free range in common property they establish feeding, drinking and rest habits that have greater negative consequences on ecosystem elements of soil, vegetation and water than the positive effects they bring. The open access regime under which this farming system operates is appraised and recommendations proposed for its amelioration. , Thesis (MPhil) (Environmental Studies) -- University of Fort Hare, 2015
- Full Text:
- Date Issued: 2015
- Authors: Chungag, Anye https://orcid.org/0000-0002-2308-9410
- Date: 2015
- Subjects: Livestock , Animal culture , Animal culture -- South Africa -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19511 , vital:43134
- Description: This study is based on Unguided Animal Husbandry as practiced in the town of Alice and its surrounding locations. It underscores the fact that though cattle are domesticated animals, they are still migratory in character. Their migratory tendency is prompted by the need of food and water and sometimes convenient rest positions. The search for food, water and rest may lead cattle to travel for many kilometres away from enclosure. This movement allows them to establish eating and drinking preferences and locations which become habitual, hence tracks develop along these paths which greatly compromise the soil, water and vegetation quality of the landscape. This study identifies such tracks and investigates the impact of cattle movement on soil physical properties and vegetation characteristics. However all this is against the back drop of the open access land regime; a mode of exploiting common property to which all have equal rights. It is a system of land management that comes with inherent challenges. Amongst them a selfish inclination of taking decisions that is motivated by egoistic interests and utmost personal gain. Secondly no thought is given to management and sustainability, subjecting common property to Haddins (1968) philosophy ‘The tragedy of the commons’. The results of the study show that when cattle is left to free range in common property they establish feeding, drinking and rest habits that have greater negative consequences on ecosystem elements of soil, vegetation and water than the positive effects they bring. The open access regime under which this farming system operates is appraised and recommendations proposed for its amelioration. , Thesis (MPhil) (Environmental Studies) -- University of Fort Hare, 2015
- Full Text:
- Date Issued: 2015