Synthesis and solvent effects on the electronic absorption and fluorescence spectral properties of substituted zinc phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283140 , vital:55914 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283140 , vital:55914 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
Synthesis and structure determination of 8-and 9-iodocamphorquinone bis (ethylene ketal)
- Magqi, Nceba, Lobb, Kevin A, Kaye, Perry T, Caira, Mino R
- Authors: Magqi, Nceba , Lobb, Kevin A , Kaye, Perry T , Caira, Mino R
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449399 , vital:74817 , xlink:href="https://doi.org/10.3184/030823407X209"
- Description: The structures of 8- and 9-iodocamphorquinone bis(ethylene ketal) have been confirmed by spectroscopic and single crystal X-ray analysis. The unexpected formation of the latter isomer is attributed to intramolecular rearrangement of the camphor skeleton, the mechanistic details of which have been explored using coset analysis.
- Full Text:
- Date Issued: 2007
- Authors: Magqi, Nceba , Lobb, Kevin A , Kaye, Perry T , Caira, Mino R
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449399 , vital:74817 , xlink:href="https://doi.org/10.3184/030823407X209"
- Description: The structures of 8- and 9-iodocamphorquinone bis(ethylene ketal) have been confirmed by spectroscopic and single crystal X-ray analysis. The unexpected formation of the latter isomer is attributed to intramolecular rearrangement of the camphor skeleton, the mechanistic details of which have been explored using coset analysis.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical properties of aryloxy tetra-substituted gallium and indium phthalocyanine derivatives
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281431 , vital:55724 , xlink:href="https://doi.org/10.1016/j.tet.2006.11.089"
- Description: The synthesis, photophysical and photochemical properties of the tetra-substituted aryloxy gallium(III) and indium(III) phthalocyanines are reported for the first time. General trends are described for photodegradation, singlet oxygen, fluorescence, and triplet quantum yields and triplet lifetimes of these compounds. The introduction of phenoxy and tert-butylphenoxy substituents on the ring resulted in lowering of fluorescence quantum yields and lifetimes, and triplet quantum yields, and an increase of kIC, kISC, and kF. Photoreduction of the complexes was observed during laser flash photolysis. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.41 to 0.91. Thus, these complexes show potential as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281431 , vital:55724 , xlink:href="https://doi.org/10.1016/j.tet.2006.11.089"
- Description: The synthesis, photophysical and photochemical properties of the tetra-substituted aryloxy gallium(III) and indium(III) phthalocyanines are reported for the first time. General trends are described for photodegradation, singlet oxygen, fluorescence, and triplet quantum yields and triplet lifetimes of these compounds. The introduction of phenoxy and tert-butylphenoxy substituents on the ring resulted in lowering of fluorescence quantum yields and lifetimes, and triplet quantum yields, and an increase of kIC, kISC, and kF. Photoreduction of the complexes was observed during laser flash photolysis. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.41 to 0.91. Thus, these complexes show potential as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
Synthesis, Photophysical and Photochemical Properties of Poly (oxyethylene)‐Substituted Phthalocyaninato Oxotitanium (IV) Complexes
- Atilla, Devrim, Durmus, Mahmut, Yılmaz, Özgür, Gürek, Ayşe Gül, Ahsen, Vefa, Nyokong, Tebello
- Authors: Atilla, Devrim , Durmus, Mahmut , Yılmaz, Özgür , Gürek, Ayşe Gül , Ahsen, Vefa , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271263 , vital:54526 , xlink:href="https://doi.org/10.1002/ejic.200700057"
- Description: The synthesis, photophysical and photochemical properties of tetra- and chlorotetrapoly(oxyethylene)-substituted oxotitanium(IV) phthalocyanines are reported for the first time. The new compounds were characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectra. These complexes showed monomeric behaviour in solution. General trends are described for photodegredation, singlet oxygen, triplet state and fluorescence quantum yields, and triplet and fluorescence lifetimes of these compounds in dimethyl sulfoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications. The complexes showed high triplet quantum yields and triplet lifetimes in DMSO. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism), were 0.72 and 0.78 for 3a and 5a, respectively. Thus, these complexes show potential as Type II photosensitizers. These complexes were also quenched by benzoquinone for fluorescence quenching studies.
- Full Text:
- Date Issued: 2007
- Authors: Atilla, Devrim , Durmus, Mahmut , Yılmaz, Özgür , Gürek, Ayşe Gül , Ahsen, Vefa , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271263 , vital:54526 , xlink:href="https://doi.org/10.1002/ejic.200700057"
- Description: The synthesis, photophysical and photochemical properties of tetra- and chlorotetrapoly(oxyethylene)-substituted oxotitanium(IV) phthalocyanines are reported for the first time. The new compounds were characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectra. These complexes showed monomeric behaviour in solution. General trends are described for photodegredation, singlet oxygen, triplet state and fluorescence quantum yields, and triplet and fluorescence lifetimes of these compounds in dimethyl sulfoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for PDT applications. The complexes showed high triplet quantum yields and triplet lifetimes in DMSO. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism), were 0.72 and 0.78 for 3a and 5a, respectively. Thus, these complexes show potential as Type II photosensitizers. These complexes were also quenched by benzoquinone for fluorescence quenching studies.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical properties of tetra-and octa-substituted gallium and indium phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271276 , vital:54529 , xlink:href="https://doi.org/10.1016/j.poly.2007.03.007"
- Description: The synthesis, photophysical and photochemical properties of the tetra- and octa-[4-(benzyloxyphenoxy)] substituted gallium(III) and indium(III) phthalocyanines are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. General trends are described for quantum yields of photodegredation, fluorescence quantum yields and lifetimes, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds in dimethylsulfoxide (DMSO). Substituted indium phthalocyanine complexes (7b–9b) showed much higher quantum yields of triplet state and shorter triplet lifetimes, compared to the substituted GaPc derivatives due to enhanced intersystem crossing (ISC) in the former. The gallium and indium phthalocyanine complexes showed phototransformation during laser irradiation due to ring reduction. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.51 to 0.94. Thus, these complexes show potential as photodynamic therapy of cancer.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271276 , vital:54529 , xlink:href="https://doi.org/10.1016/j.poly.2007.03.007"
- Description: The synthesis, photophysical and photochemical properties of the tetra- and octa-[4-(benzyloxyphenoxy)] substituted gallium(III) and indium(III) phthalocyanines are reported for the first time. The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. General trends are described for quantum yields of photodegredation, fluorescence quantum yields and lifetimes, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds in dimethylsulfoxide (DMSO). Substituted indium phthalocyanine complexes (7b–9b) showed much higher quantum yields of triplet state and shorter triplet lifetimes, compared to the substituted GaPc derivatives due to enhanced intersystem crossing (ISC) in the former. The gallium and indium phthalocyanine complexes showed phototransformation during laser irradiation due to ring reduction. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) ranged from 0.51 to 0.94. Thus, these complexes show potential as photodynamic therapy of cancer.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical studies of new water-soluble indium (III) phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283976 , vital:56007 , xlink:href="https://doi.org/10.1039/b618478b"
- Description: The preparation of water-soluble indium(III)phthalocyanine complexes is described for the first time in this study. Peripherally and non-peripherally 3-hydroxypyridine tetrasubstituted indium(III) phthalocyanines (5a, 6a) and their quaternarized derivatives (5b, 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b, 6b) show excellent solubility in water, which makes them potential photosensitizers for use in photodynamic therapy (PDT) applications. Photochemical and photophysical measurements were conducted on 3-pyridyloxy appended indium(III) phthalocyanines in dimethylsulfoxide (DMSO) for non-ionic (5b, 6b) derivatives. General trends are described for quantum yields of photodegradation, fluorescence lifetimes, fluorescence quantum yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) are very high (ΦΔ > 0.55). Thus, these complexes may be useful as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
Synthesis, photophysical and photochemical studies of new water-soluble indium (III) phthalocyanines
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283976 , vital:56007 , xlink:href="https://doi.org/10.1039/b618478b"
- Description: The preparation of water-soluble indium(III)phthalocyanine complexes is described for the first time in this study. Peripherally and non-peripherally 3-hydroxypyridine tetrasubstituted indium(III) phthalocyanines (5a, 6a) and their quaternarized derivatives (5b, 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b, 6b) show excellent solubility in water, which makes them potential photosensitizers for use in photodynamic therapy (PDT) applications. Photochemical and photophysical measurements were conducted on 3-pyridyloxy appended indium(III) phthalocyanines in dimethylsulfoxide (DMSO) for non-ionic (5b, 6b) derivatives. General trends are described for quantum yields of photodegradation, fluorescence lifetimes, fluorescence quantum yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The singlet oxygen quantum yields (ΦΔ), which give an indication of the potential of the complexes as photosensitizers in applications where singlet oxygen is required (Type II mechanism) are very high (ΦΔ > 0.55). Thus, these complexes may be useful as Type II photosensitizers.
- Full Text:
- Date Issued: 2007
The biology and laboratory host range of the weevil, Listronotus marginicollis (Hustache)(Coleoptera: Curculionidae), a natural enemy of the invasive aquatic weed, parrot's feather, Myriophyllum aquaticum (Velloso) Verde (Haloragaceae).
- Oberholzer, I G, Mafokoane, D L, Hill, Martin P
- Authors: Oberholzer, I G , Mafokoane, D L , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451555 , vital:75059 , https://hdl.handle.net/10520/EJC32727
- Description: Myriophyllum aquaticum (Velloso) Verde (Haloragaceae), parrot's feather, is a rooted aquatic plant, with stems of up to 3 m long and leafy terminal shoots. The plant roots in shallow water to form a dense tangle of stems and roots. The shoots emerge 200-500 mm above the water surface (Cilliers 1999). The leaves of the plant are feathery and occur in whorls. The stem-boring weevil, Listronotus marginicollis (Hustache) (Coleoptera: Curculionidae), was next considered as the most promising additional biological control agent for the control of M. aquaticum in southern Africa (Cilliers 1999).
- Full Text:
- Date Issued: 2007
- Authors: Oberholzer, I G , Mafokoane, D L , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451555 , vital:75059 , https://hdl.handle.net/10520/EJC32727
- Description: Myriophyllum aquaticum (Velloso) Verde (Haloragaceae), parrot's feather, is a rooted aquatic plant, with stems of up to 3 m long and leafy terminal shoots. The plant roots in shallow water to form a dense tangle of stems and roots. The shoots emerge 200-500 mm above the water surface (Cilliers 1999). The leaves of the plant are feathery and occur in whorls. The stem-boring weevil, Listronotus marginicollis (Hustache) (Coleoptera: Curculionidae), was next considered as the most promising additional biological control agent for the control of M. aquaticum in southern Africa (Cilliers 1999).
- Full Text:
- Date Issued: 2007
The deployment of an e-commerce platform and related projects in a rural area in South Africa
- Dalvit, Lorenzo, Muyingi, H Hyppolite, Terzoli, Alfredo, Thinyane, Mamello
- Authors: Dalvit, Lorenzo , Muyingi, H Hyppolite , Terzoli, Alfredo , Thinyane, Mamello
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428545 , vital:72519 , https://nru.uncst.go.ug/bitstream/handle/123456789/6552/Information%20Communica-tion%20Technologies%20%20page%20410.pdf?sequence=1andisAllowed=y#page=256
- Description: In our paper we describe the development and deployment of an ecommerce platform in Dwesa, a rural area in the former homeland of Transkei in South Africa. The system is designed to promote tourism and advertise local arts, crafts and music, and it entails a number of re-lated projects. Deployment of infrastructure, technical support, promo-tion of the initiative and teaching of computer literacy take place during monthly visits of approximately one week, and involve young research-ers from two universities (one previously disadvantaged; the other his-torically privileged). This ensures a synergy between technical exper-tise and understanding of the local context. Findings so far emphasise the importance of contextualising the intervention to suit local needs and adjust to the local context. The platform is currently being extended to include e-government, e-learning and e-health capabilities. If proven successful, this model can be exported to similar areas in South africa and in the rest of Africa. This could open up potential opportunities for the still unexplored market for ICT in rural Africa.
- Full Text:
- Date Issued: 2007
- Authors: Dalvit, Lorenzo , Muyingi, H Hyppolite , Terzoli, Alfredo , Thinyane, Mamello
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428545 , vital:72519 , https://nru.uncst.go.ug/bitstream/handle/123456789/6552/Information%20Communica-tion%20Technologies%20%20page%20410.pdf?sequence=1andisAllowed=y#page=256
- Description: In our paper we describe the development and deployment of an ecommerce platform in Dwesa, a rural area in the former homeland of Transkei in South Africa. The system is designed to promote tourism and advertise local arts, crafts and music, and it entails a number of re-lated projects. Deployment of infrastructure, technical support, promo-tion of the initiative and teaching of computer literacy take place during monthly visits of approximately one week, and involve young research-ers from two universities (one previously disadvantaged; the other his-torically privileged). This ensures a synergy between technical exper-tise and understanding of the local context. Findings so far emphasise the importance of contextualising the intervention to suit local needs and adjust to the local context. The platform is currently being extended to include e-government, e-learning and e-health capabilities. If proven successful, this model can be exported to similar areas in South africa and in the rest of Africa. This could open up potential opportunities for the still unexplored market for ICT in rural Africa.
- Full Text:
- Date Issued: 2007
The effect of temperature and salinity on oxygen consumption in the brachyuran crab Cyclograpsus punctatus (Crustacea: Decapoda: Grapsidae)
- Winch, James W W, Hodgson, Alan N
- Authors: Winch, James W W , Hodgson, Alan N
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447426 , vital:74624 , https://doi.org/10.1080/15627020.2007.11407384
- Description: The aquatic oxygen consumption of the estuarine brachyuran crab, Cyclograpsus punctatus, was investigated after a 24-hour acclimation period at different temperature (12.5, 20, 30°C) and salinity (9, 17.5, 35, and 44°) combinations . Salinity had no significant effect on oxygen consumption at 12.5 and 20°C in both large and small crabs. At 30°C and 44°, however, the rate of oxygen consumption declined in large crabs (from 0.233 to 0.176 mg O2 g wwt/h) and increased in small crabs (0.300 to 0.469 mg O2 g wwt/h). There was also a significant increase in the oxygen consumption (0.300 to 0.536 mg O2 g wwt/h) of small crabs at the high temperature/low salinity combination. Temperature had a significant effect on the rate of oxygen consumption at all salinities, with Q10 values ranging from 1.16 to 2.85. In all cases the mass-specific oxygen consumption rate of small crabs was higher than that of large crabs. The results suggest that the confinement of this species to the lower reaches of estuaries may, in part, be due to physiological constraints on juveniles and small individuals.
- Full Text:
- Date Issued: 2007
- Authors: Winch, James W W , Hodgson, Alan N
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447426 , vital:74624 , https://doi.org/10.1080/15627020.2007.11407384
- Description: The aquatic oxygen consumption of the estuarine brachyuran crab, Cyclograpsus punctatus, was investigated after a 24-hour acclimation period at different temperature (12.5, 20, 30°C) and salinity (9, 17.5, 35, and 44°) combinations . Salinity had no significant effect on oxygen consumption at 12.5 and 20°C in both large and small crabs. At 30°C and 44°, however, the rate of oxygen consumption declined in large crabs (from 0.233 to 0.176 mg O2 g wwt/h) and increased in small crabs (0.300 to 0.469 mg O2 g wwt/h). There was also a significant increase in the oxygen consumption (0.300 to 0.536 mg O2 g wwt/h) of small crabs at the high temperature/low salinity combination. Temperature had a significant effect on the rate of oxygen consumption at all salinities, with Q10 values ranging from 1.16 to 2.85. In all cases the mass-specific oxygen consumption rate of small crabs was higher than that of large crabs. The results suggest that the confinement of this species to the lower reaches of estuaries may, in part, be due to physiological constraints on juveniles and small individuals.
- Full Text:
- Date Issued: 2007
The effects of buffer molarity, agitation rate and mesh size on verapamil release from modified release mini-tablets using USP Apparatus 3
- Khamanga, Sandile M, Walker, Roderick B
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6386 , http://hdl.handle.net/10962/d1006307
- Description: The effects of agitation rate, buffer molarity,and mesh size on the dissolution rate of verapamil hydrochloride from sustained release matrix tablets were studied using USP Apparatus 3. Eudragit® and Carbopol® were used as rate-retarding polymers in tablets prepared by wet granulation.The study was conducted to determine whether the drugs exhibit similar release characteristics when tested under the same dissolution conditions. It was found that the dissolution rate of verapamil hydrochloride was affected by the variables assessed in these studies.
- Full Text:
- Date Issued: 2007
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2007
- Language: English
- Type: text , Article
- Identifier: vital:6386 , http://hdl.handle.net/10962/d1006307
- Description: The effects of agitation rate, buffer molarity,and mesh size on the dissolution rate of verapamil hydrochloride from sustained release matrix tablets were studied using USP Apparatus 3. Eudragit® and Carbopol® were used as rate-retarding polymers in tablets prepared by wet granulation.The study was conducted to determine whether the drugs exhibit similar release characteristics when tested under the same dissolution conditions. It was found that the dissolution rate of verapamil hydrochloride was affected by the variables assessed in these studies.
- Full Text:
- Date Issued: 2007
The effects of fire on post-fire seed germination of selected Savanna woody species
- Authors: Shackleton, Charlie M
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183104 , vital:43912 , xlink:href=" https://doi.org/10.1111/j.1365-2028.2007.00766.x"
- Description: Although fire is recognized as an integral component of savanna dynamics, there is a dearth of understanding of its impacts on woody plant seeds. This study examined the impacts of fire in stimulating or constraining post-fire germination of seven common savanna woody species. Seeds of two species (Combretum hereroense and Euclea natalensis) failed to germinate irrespective of fire treatment. For the remaining five species, fire effects were dependent on seed location as either on the soil surface or buried. For surface seeds, fire effects reduced germination in four of the species, and stimulated it for one species (Acacia swazica). For buried seeds, fire had no effect. A significant proportion of surface seeds were destroyed by fire, and overall germination was higher for buried seed for most species other than A. swazica.
- Full Text:
- Date Issued: 2007
- Authors: Shackleton, Charlie M
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183104 , vital:43912 , xlink:href=" https://doi.org/10.1111/j.1365-2028.2007.00766.x"
- Description: Although fire is recognized as an integral component of savanna dynamics, there is a dearth of understanding of its impacts on woody plant seeds. This study examined the impacts of fire in stimulating or constraining post-fire germination of seven common savanna woody species. Seeds of two species (Combretum hereroense and Euclea natalensis) failed to germinate irrespective of fire treatment. For the remaining five species, fire effects were dependent on seed location as either on the soil surface or buried. For surface seeds, fire effects reduced germination in four of the species, and stimulated it for one species (Acacia swazica). For buried seeds, fire had no effect. A significant proportion of surface seeds were destroyed by fire, and overall germination was higher for buried seed for most species other than A. swazica.
- Full Text:
- Date Issued: 2007
The Emerging Role of ubuntu-botho in Developing a Consensual South African Legal Culture
- Authors: Kruuse, Helen , Midgley, Rob
- Date: 2007
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54224 , vital:26413 , https://dspace.library.uu.nl/handle/1874/27652
- Description: Legal culture in apartheid South Africa has variously been described as conservative and positivist, with judicial deference to the executive and to parliamentary sovereignty; formalistic, technical and authoritarian; and ‘of reasoned argument’ and justification. Until 1994, law drew its legitimacy from the very fact that it was state sanctioned, and the material context or the social aftermath of the application of a rule was in many instances deemed irrelevant. However, the adoption, first, of the interim Constitution, and later the final Constitution, saw a desire to transform this legal culture. The Constitution is now more than a formal document regulating public power: it also embodies a normative value system in terms of which judges are called upon to interpret laws and their application.
- Full Text:
- Date Issued: 2007
- Authors: Kruuse, Helen , Midgley, Rob
- Date: 2007
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54224 , vital:26413 , https://dspace.library.uu.nl/handle/1874/27652
- Description: Legal culture in apartheid South Africa has variously been described as conservative and positivist, with judicial deference to the executive and to parliamentary sovereignty; formalistic, technical and authoritarian; and ‘of reasoned argument’ and justification. Until 1994, law drew its legitimacy from the very fact that it was state sanctioned, and the material context or the social aftermath of the application of a rule was in many instances deemed irrelevant. However, the adoption, first, of the interim Constitution, and later the final Constitution, saw a desire to transform this legal culture. The Constitution is now more than a formal document regulating public power: it also embodies a normative value system in terms of which judges are called upon to interpret laws and their application.
- Full Text:
- Date Issued: 2007
The habitus of the dominant: addressing rape and sexual assault at Rhodes University
- de Klerk, Vivian A, Klazinga, Larissa, McNeill, Amy
- Authors: de Klerk, Vivian A , Klazinga, Larissa , McNeill, Amy
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453352 , vital:75247 , https://doi.org/10.1080/10130950.2007.9674885
- Description: This article seeks to describe the changing ways in which Rhodes University has addressed rape and sexual assault. By highlighting the evolution of policies and methodologies, it aims to identify possible shortcomings of the past, and offer new strategies and principles which may be useful to fellow institutions grappling with sexual violence issues.
- Full Text:
- Date Issued: 2007
- Authors: de Klerk, Vivian A , Klazinga, Larissa , McNeill, Amy
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453352 , vital:75247 , https://doi.org/10.1080/10130950.2007.9674885
- Description: This article seeks to describe the changing ways in which Rhodes University has addressed rape and sexual assault. By highlighting the evolution of policies and methodologies, it aims to identify possible shortcomings of the past, and offer new strategies and principles which may be useful to fellow institutions grappling with sexual violence issues.
- Full Text:
- Date Issued: 2007
The humanities, vocationalism and the public good: exploring 'the Hamlet factor'
- Authors: Wright, Laurence
- Date: 2007
- Language: English
- Type: text , article
- Identifier: vital:7028 , http://hdl.handle.net/10962/d1007214 , https://doi.org/10.1080/17535360712331393503
- Description: preprint , This paper argues that the social mission of the humanities is no longer well understood by the public, sometimes not even by the very institutions seeking to attract students to these disciplines, the universities. It becomes difficult to argue for the cogency of research in the humanities, let alone for a specific national research agenda, when the general relation between the humanities and society is widely mistaken. To address such misapprehensions, the discussion outlines as clearly as possible the characteristic procedures of the humanities, the manner in which they inform individual and social transformation, and the contemporary predicament which makes them more rather than less needed in society’s repertoire of educational resources. With this understanding in place, the paper then puts forward suggestions for strengthening research in the humanities as part of a broader programme to renovate the humanities in the South African education system.
- Full Text:
- Date Issued: 2007
- Authors: Wright, Laurence
- Date: 2007
- Language: English
- Type: text , article
- Identifier: vital:7028 , http://hdl.handle.net/10962/d1007214 , https://doi.org/10.1080/17535360712331393503
- Description: preprint , This paper argues that the social mission of the humanities is no longer well understood by the public, sometimes not even by the very institutions seeking to attract students to these disciplines, the universities. It becomes difficult to argue for the cogency of research in the humanities, let alone for a specific national research agenda, when the general relation between the humanities and society is widely mistaken. To address such misapprehensions, the discussion outlines as clearly as possible the characteristic procedures of the humanities, the manner in which they inform individual and social transformation, and the contemporary predicament which makes them more rather than less needed in society’s repertoire of educational resources. With this understanding in place, the paper then puts forward suggestions for strengthening research in the humanities as part of a broader programme to renovate the humanities in the South African education system.
- Full Text:
- Date Issued: 2007
The relationship between female pupal mass and fecundity of Gratiana spadicea (Klug, 1829)(Coleoptera: Chrysomelidae)
- Czypionka, K, Hill, Martin P
- Authors: Czypionka, K , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451568 , vital:75060 , https://hdl.handle.net/10520/EJC32729
- Description: In the early 1900s Solanum sisymbriifolium Lamarck (Solanaceae), commonly known as dense thorned bitter apple and previously referred to as wild tomato, was introduced into southern Africa and has since become an invasive weed (Hill and Hulley 1995, 1996). In 1994 a chrysomelid beetle, Gratiana spadicea (Klug, 1829) (Coleoptera : Chrysomelidae), was introduced as a biological control agent against the weed (Hill and Hulley 1995). Prior to its release, various specificity tests were conducted to identify the potential host range of this agent. These included larval survival and adult choice and no-choice tests on several native and commercial Solanum species. These specificity tests generally identify the potential host range of an agent accurately, but fail to predict the magnitude of non-target risks in the field (Wan and Harris 1997; Louda et al. 2003).
- Full Text:
- Date Issued: 2007
- Authors: Czypionka, K , Hill, Martin P
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451568 , vital:75060 , https://hdl.handle.net/10520/EJC32729
- Description: In the early 1900s Solanum sisymbriifolium Lamarck (Solanaceae), commonly known as dense thorned bitter apple and previously referred to as wild tomato, was introduced into southern Africa and has since become an invasive weed (Hill and Hulley 1995, 1996). In 1994 a chrysomelid beetle, Gratiana spadicea (Klug, 1829) (Coleoptera : Chrysomelidae), was introduced as a biological control agent against the weed (Hill and Hulley 1995). Prior to its release, various specificity tests were conducted to identify the potential host range of this agent. These included larval survival and adult choice and no-choice tests on several native and commercial Solanum species. These specificity tests generally identify the potential host range of an agent accurately, but fail to predict the magnitude of non-target risks in the field (Wan and Harris 1997; Louda et al. 2003).
- Full Text:
- Date Issued: 2007
The relevance of sustainable development principles and goals through a case study of Gold Fields and Living Gold
- Authors: Ferreira, Adrian
- Date: 2007
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192977 , vital:45286
- Description: The conventional definition of sustainable development as proposed by the Brundtland Report (United Nations, 1987), involving the integration of economic, social and environmental components, is widely accepted. Presumed benefits of these current framework applications tend to perpetuate a business as usual status, with no real sustainable development occurring. The growing debate surrounding this topic makes the case for relevant and contextual inputs to be included into sustainable development objectives. A case study, of Gold Fields and Living Gold, attempts to create a deeper understanding of the components of this debate, and begins to contextualise sustainable development principles, goals and their outcomes. This is carried out though an enquiry of the use of cultural development as a fourth sustainable development category. The case study includes the opinions of a directly affected local community entity (Living Gold) in order to observe the difference between the two organisations (Gold Fields and Living Gold). During the study, the focus began to move away from purely unabated growth impacts and looked to the creation and fostering of resilience and flexibility by the use of adaptive management. In breeding states of resilience, it was recognised that cultural impacts played an important role in ensuring long term systemic resilience. The case study involved assessing the feedback and responses of strategically selected individuals at both organisations, with Gold Fields representing a more western centric entity and Living Gold a formal representation of a traditional/ indigenous community. Similarities and differences were assessed in order to understand how current sustainable development criteria might differ between organisations that have different end objectives in mind, yet are dependent on each other. The findings resulted in a perspective of how culture could be used to describe the qualities of a local community, and how to begin aligning development goals with affected communities. The result was the development of the Integrated Resilience Sustainability Method and the consequent development of the Balanced Bottom Line Framework, which seeks to promote sustainable development along the lines of economic, social, environmental and cultural development. , Thesis (MBA) -- Faculty of Commerce, Rhodes Investec Business School, 2007
- Full Text:
- Date Issued: 2007
- Authors: Ferreira, Adrian
- Date: 2007
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192977 , vital:45286
- Description: The conventional definition of sustainable development as proposed by the Brundtland Report (United Nations, 1987), involving the integration of economic, social and environmental components, is widely accepted. Presumed benefits of these current framework applications tend to perpetuate a business as usual status, with no real sustainable development occurring. The growing debate surrounding this topic makes the case for relevant and contextual inputs to be included into sustainable development objectives. A case study, of Gold Fields and Living Gold, attempts to create a deeper understanding of the components of this debate, and begins to contextualise sustainable development principles, goals and their outcomes. This is carried out though an enquiry of the use of cultural development as a fourth sustainable development category. The case study includes the opinions of a directly affected local community entity (Living Gold) in order to observe the difference between the two organisations (Gold Fields and Living Gold). During the study, the focus began to move away from purely unabated growth impacts and looked to the creation and fostering of resilience and flexibility by the use of adaptive management. In breeding states of resilience, it was recognised that cultural impacts played an important role in ensuring long term systemic resilience. The case study involved assessing the feedback and responses of strategically selected individuals at both organisations, with Gold Fields representing a more western centric entity and Living Gold a formal representation of a traditional/ indigenous community. Similarities and differences were assessed in order to understand how current sustainable development criteria might differ between organisations that have different end objectives in mind, yet are dependent on each other. The findings resulted in a perspective of how culture could be used to describe the qualities of a local community, and how to begin aligning development goals with affected communities. The result was the development of the Integrated Resilience Sustainability Method and the consequent development of the Balanced Bottom Line Framework, which seeks to promote sustainable development along the lines of economic, social, environmental and cultural development. , Thesis (MBA) -- Faculty of Commerce, Rhodes Investec Business School, 2007
- Full Text:
- Date Issued: 2007
The status of the southern ground-hornbill in the Grahamstown region, Eastern Cape, South Africa
- Hulley, Patrick E, Craig, Adrian J F K
- Authors: Hulley, Patrick E , Craig, Adrian J F K
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447909 , vital:74683 , https://www.tandfonline.com/doi/pdf/10.2989/OSTRICH.2007.78.1.13.57
- Description: The Eastern Cape has been the southernmost limit of distribution for the Southern Ground-Hornbill Bucorvus leadbeateri throughout the period for which there are written records (Vernon 1986, Vernon and Herremans 1997). No records are known west of Port Elizabeth and the only ones from this 1 map square (33 S 27 E) date from the nineteenth century. Vernon (1986) noted that nest and roost sites for groundhornbills were in large trees or on cliffs, from which the birds commuted to forage in open country. The forest/thicket and grassland mosaic in the Eastern Cape is apparently ancient (Skead 1987), but the grassland sector has been greatly modified by agriculture and human settlement. Since the assessment of the Southern Ground-Hornbill’s status as ‘vulnerable’in the latest Red Data Book (Barnes 2000), it has been suggested that populations in South Africa have declined to a point where its true status is ‘endangered’but this revision was not accepted by IUCN (AC Kemp, pers. comm.). The recent initiative by the Mabula-based NGO, the Ground-hornbill Research and Conservation Project, to reintroduce birds to the Eastern Cape, prompted us to examine records of sightings in this region. The main focus is the Grahamstown map square 33 S 26 E, in which the release site of the first birds—Shamwari Private Game Reserve—is situated. Our source is the published records in Diaz Diary, the newsletter of the Diaz Cross Bird Club, which has branches in Grahamstown and Kenton-on-Sea, covering the period 1978–2004 inclusive.
- Full Text:
- Date Issued: 2007
- Authors: Hulley, Patrick E , Craig, Adrian J F K
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447909 , vital:74683 , https://www.tandfonline.com/doi/pdf/10.2989/OSTRICH.2007.78.1.13.57
- Description: The Eastern Cape has been the southernmost limit of distribution for the Southern Ground-Hornbill Bucorvus leadbeateri throughout the period for which there are written records (Vernon 1986, Vernon and Herremans 1997). No records are known west of Port Elizabeth and the only ones from this 1 map square (33 S 27 E) date from the nineteenth century. Vernon (1986) noted that nest and roost sites for groundhornbills were in large trees or on cliffs, from which the birds commuted to forage in open country. The forest/thicket and grassland mosaic in the Eastern Cape is apparently ancient (Skead 1987), but the grassland sector has been greatly modified by agriculture and human settlement. Since the assessment of the Southern Ground-Hornbill’s status as ‘vulnerable’in the latest Red Data Book (Barnes 2000), it has been suggested that populations in South Africa have declined to a point where its true status is ‘endangered’but this revision was not accepted by IUCN (AC Kemp, pers. comm.). The recent initiative by the Mabula-based NGO, the Ground-hornbill Research and Conservation Project, to reintroduce birds to the Eastern Cape, prompted us to examine records of sightings in this region. The main focus is the Grahamstown map square 33 S 26 E, in which the release site of the first birds—Shamwari Private Game Reserve—is situated. Our source is the published records in Diaz Diary, the newsletter of the Diaz Cross Bird Club, which has branches in Grahamstown and Kenton-on-Sea, covering the period 1978–2004 inclusive.
- Full Text:
- Date Issued: 2007
The synthesis, fluorescence behaviour and singlet oxygen studies of new water-soluble cationic gallium (III) phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/280207 , vital:55586 , xlink:href="https://doi.org/10.1016/j.inoche.2006.11.012"
- Description: The preparation of cationic water-soluble gallium phthalocyanine derivatives are described for the first time. Peripheral and non-peripheral 3-hydroxypyridine tetrasubstituted gallium(III)phthalocyanines (5a, 6a) and their quaternarized derivatives (5b and 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b and 6b) are soluble in water and not aggregated (in water and in organic solvents) within a wide concentration range. General trends are described for singlet oxygen quantum yields, fluorescence quantum yields and fluorescence lifetimes of these compounds. These complexes showed better singlet oxygen quantum yields in water than the related quarternarized porphyrazine complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/280207 , vital:55586 , xlink:href="https://doi.org/10.1016/j.inoche.2006.11.012"
- Description: The preparation of cationic water-soluble gallium phthalocyanine derivatives are described for the first time. Peripheral and non-peripheral 3-hydroxypyridine tetrasubstituted gallium(III)phthalocyanines (5a, 6a) and their quaternarized derivatives (5b and 6b) have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. The quaternarized compounds (5b and 6b) are soluble in water and not aggregated (in water and in organic solvents) within a wide concentration range. General trends are described for singlet oxygen quantum yields, fluorescence quantum yields and fluorescence lifetimes of these compounds. These complexes showed better singlet oxygen quantum yields in water than the related quarternarized porphyrazine complexes.
- Full Text:
- Date Issued: 2007
The thirtieth anniversary of the Soweto uprisings: reading the shadow in Sam Nzima's iconic photograph of Hector Pieterson
- Authors: Simbao, Ruth K
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147536 , vital:38647 , https://doi.org/10.1162/afar.2007.40.2.52
- Description: This haunting photograph (Fig. 1) from the 1976 Soweto Uprisings in South Africa is often referred to as the single most important photograph to emerge from the struggle against apartheid (Purtilo 1999:22). According to South African film director Feizel Mamdoo, there are particular moments in history that are defined by photographic, celluloid, or television images, such as the world famous photograph of the Saigon girl, naked and burning from napalm (Worsdale 1998; see also Richards 2001). He argues that the iconic photograph by Sam Nzima depicting Hector Pieterson being carried in the arms of Mbuyisa Makhubu, with his distraught sister Antionette1 running alongside, is comparable in the way that “it marks history, both social and personal” (Worsdale 1998).
- Full Text:
- Date Issued: 2007
- Authors: Simbao, Ruth K
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147536 , vital:38647 , https://doi.org/10.1162/afar.2007.40.2.52
- Description: This haunting photograph (Fig. 1) from the 1976 Soweto Uprisings in South Africa is often referred to as the single most important photograph to emerge from the struggle against apartheid (Purtilo 1999:22). According to South African film director Feizel Mamdoo, there are particular moments in history that are defined by photographic, celluloid, or television images, such as the world famous photograph of the Saigon girl, naked and burning from napalm (Worsdale 1998; see also Richards 2001). He argues that the iconic photograph by Sam Nzima depicting Hector Pieterson being carried in the arms of Mbuyisa Makhubu, with his distraught sister Antionette1 running alongside, is comparable in the way that “it marks history, both social and personal” (Worsdale 1998).
- Full Text:
- Date Issued: 2007
Think Piece : an opening dialogue with Think Pieces and feature articles on learning in a changing world in this journal
- Authors: Lotz-Sisitka, Heila
- Date: 2007
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59602 , vital:27630 , https://www.ajol.info/index.php/sajee/article/view/122734
- Description: From Conclusion:This opening Think Piece invites you into such a dialogue, with this journal, its words and flows of meaning, and with the World Environmental Education Congress, its words and flows of meaning. Dialogue, as explained by Bohm, and as illustrated in the thought experiments in this paper, is a process of creatively and experimentally seeking out meaning and coherence through listening, and through deeper explorations of the tacit, implicate order. It is also a free process, where you as individual are invited to seek out the relations between your thoughts and the collective. Welcome to the process.
- Full Text:
- Date Issued: 2007
- Authors: Lotz-Sisitka, Heila
- Date: 2007
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59602 , vital:27630 , https://www.ajol.info/index.php/sajee/article/view/122734
- Description: From Conclusion:This opening Think Piece invites you into such a dialogue, with this journal, its words and flows of meaning, and with the World Environmental Education Congress, its words and flows of meaning. Dialogue, as explained by Bohm, and as illustrated in the thought experiments in this paper, is a process of creatively and experimentally seeking out meaning and coherence through listening, and through deeper explorations of the tacit, implicate order. It is also a free process, where you as individual are invited to seek out the relations between your thoughts and the collective. Welcome to the process.
- Full Text:
- Date Issued: 2007