Nonlinear optical properties of metal free and nickel binuclear phthalocyanines
- Kabwe, Kapambwe P, Louzada, Marcel, Britton, Jonathan, Olomola, Temitope O, Nyokong, Tebello, Khene, Samson M
- Authors: Kabwe, Kapambwe P , Louzada, Marcel , Britton, Jonathan , Olomola, Temitope O , Nyokong, Tebello , Khene, Samson M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186846 , vital:44539 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.05.003"
- Description: This work employs the open and closed Z-scan aperture technique to comparatively study the nonlinear optical (NLO) properties of nickel and metal free 4-tert-butylphenoxy phthalocyanine, biphenyl bridged bis-4-tert-butylphenoxy phthalocyanine and naphthalene bridged bis-4-tert-butylphenoxy phthalocyanine. Density functional theory (DFT) calculations of dipolar and octupolar ( J=1 and J=3) contribution were determined theoretically from hyper-Rayleigh scattering (HRS) response ( HRS) values.
- Full Text:
- Date Issued: 2019
- Authors: Kabwe, Kapambwe P , Louzada, Marcel , Britton, Jonathan , Olomola, Temitope O , Nyokong, Tebello , Khene, Samson M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186846 , vital:44539 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.05.003"
- Description: This work employs the open and closed Z-scan aperture technique to comparatively study the nonlinear optical (NLO) properties of nickel and metal free 4-tert-butylphenoxy phthalocyanine, biphenyl bridged bis-4-tert-butylphenoxy phthalocyanine and naphthalene bridged bis-4-tert-butylphenoxy phthalocyanine. Density functional theory (DFT) calculations of dipolar and octupolar ( J=1 and J=3) contribution were determined theoretically from hyper-Rayleigh scattering (HRS) response ( HRS) values.
- Full Text:
- Date Issued: 2019
Nonlinear optical responses of carbazole-substituted phthalocyanines conjugated to graphene quantum dots and in thin films
- Majeed, Shereen A, Nwaji, Njemuwa, Mack, John, Nyokong, Tebello, Makhseed, Saad
- Authors: Majeed, Shereen A , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello , Makhseed, Saad
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186938 , vital:44549 , xlink:href="https://doi.org/10.1016/j.jlumin.2019.04.034"
- Description: Three different phthalocyanine complexes substituted with carbazoles were conjugated to graphene quantum dots (GQDs) through π–π stacking. The morphologies, sizes, and crystallinities of the nanoconjugates were determined using Raman spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The nonlinear optical (NLO) properties of the metallophthalocyanines alone and when conjugated to the GQD nanomaterial in different solvents, as well as after having been embedded in thin films, were studied. The effects of the different substituents and solvents on the NLO properties of the metallophthalocyanines were evaluated. Enhancements in the photophysical properties of the complexes upon conjugation with the nanomaterial were observed. Fluorescence quantum yields, fluorescence lifetimes, triplet quantum yields, and triplet lifetimes were measured for the complexes, and for their conjugates in DMSO.
- Full Text:
- Date Issued: 2019
- Authors: Majeed, Shereen A , Nwaji, Njemuwa , Mack, John , Nyokong, Tebello , Makhseed, Saad
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186938 , vital:44549 , xlink:href="https://doi.org/10.1016/j.jlumin.2019.04.034"
- Description: Three different phthalocyanine complexes substituted with carbazoles were conjugated to graphene quantum dots (GQDs) through π–π stacking. The morphologies, sizes, and crystallinities of the nanoconjugates were determined using Raman spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The nonlinear optical (NLO) properties of the metallophthalocyanines alone and when conjugated to the GQD nanomaterial in different solvents, as well as after having been embedded in thin films, were studied. The effects of the different substituents and solvents on the NLO properties of the metallophthalocyanines were evaluated. Enhancements in the photophysical properties of the complexes upon conjugation with the nanomaterial were observed. Fluorescence quantum yields, fluorescence lifetimes, triplet quantum yields, and triplet lifetimes were measured for the complexes, and for their conjugates in DMSO.
- Full Text:
- Date Issued: 2019
Optical limiting and femtosecond pump-probe transient absorbance properties of a 3, 5-distyrylBODIPY dye
- Ngoy, Bokolombe P, May, Aviwe K, Mack, John, Nyokong, Tebello
- Authors: Ngoy, Bokolombe P , May, Aviwe K , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186835 , vital:44538 , xlink:href="https://doi.org/10.3389/fchem.2019.00740"
- Description: The optical limiting (OL) properties of a 3,5-di-p-benzyloxystyrylBODIPY dye with an p-acetamidophenyl moiety at the meso-position have been investigated by using the open-aperture Z-scan technique at 532 nm with 10 ns laser pulses. There is a ca. 140 nm red shift of the main spectral band to 644 nm relative to the corresponding BODIPY core dye, due to the incorporation of p-benzyloxystyryl groups at the 3,5-positions. As a result, there is relatively weak absorbance across most of the visible region under ambient light conditions. Analysis of the observed reverse saturable absorbance (RSA) profiles demonstrates that the dye is potentially suitable for use in optical limiting applications as has been reported previously for other 3,5-distyrylBODIPY dyes. Time-resolved transient absorption spectroscopy and kinetic studies with femtosecond and nanosecond scale laser pulses provide the first direct spectral evidence that excited state absorption (ESA) from the S1 state is responsible for the observed OL properties.
- Full Text:
- Date Issued: 2019
- Authors: Ngoy, Bokolombe P , May, Aviwe K , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186835 , vital:44538 , xlink:href="https://doi.org/10.3389/fchem.2019.00740"
- Description: The optical limiting (OL) properties of a 3,5-di-p-benzyloxystyrylBODIPY dye with an p-acetamidophenyl moiety at the meso-position have been investigated by using the open-aperture Z-scan technique at 532 nm with 10 ns laser pulses. There is a ca. 140 nm red shift of the main spectral band to 644 nm relative to the corresponding BODIPY core dye, due to the incorporation of p-benzyloxystyryl groups at the 3,5-positions. As a result, there is relatively weak absorbance across most of the visible region under ambient light conditions. Analysis of the observed reverse saturable absorbance (RSA) profiles demonstrates that the dye is potentially suitable for use in optical limiting applications as has been reported previously for other 3,5-distyrylBODIPY dyes. Time-resolved transient absorption spectroscopy and kinetic studies with femtosecond and nanosecond scale laser pulses provide the first direct spectral evidence that excited state absorption (ESA) from the S1 state is responsible for the observed OL properties.
- Full Text:
- Date Issued: 2019
Overcoming essentialism in community psychology: The use of a narrative-discursive approach within African feminisms
- Mavuso, Jabulile M-J J, Chiweshe, Malvern T, Macleod, Catriona I
- Authors: Mavuso, Jabulile M-J J , Chiweshe, Malvern T , Macleod, Catriona I
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434131 , vital:73033 , ISBN 978-3-030-20000-8 , https://doi.org/10.1007/978-3-030-20001-5_2
- Description: A decolonial feminist community psychology approach understands individual experience as being embedded in, enabled and shaped by discursive and social power relations, and that transformative change is only possible through this contextualised understanding of individual experiences. African feminisms have been concerned with the challenging task of exploring and producing accounts of the complexity and multiplicity in womxn’s (and mxn’s) experiences of localised, multiple forms of oppression and the resistances enacted against them. We demonstrate how the utilisation of a narrative-discursive method in research that is guided by poststructural and postcolonial African feminist theorising may be a useful tool in realising the goals and aims of both decolonial feminist community psychology, and African feminist theorising. In this chapter, we draw on research that explored Zimbabwean womxn’s narratives of abortion decision-making and South African womxn’s and healthcare providers’ narratives of their experiences of the pre-abortion counselling healthcare encounter in the Eastern Cape public health sector. We also draw on our own intervention, a policy brief that had been developed into pre-abortion counselling guidelines which were informed by womxn’s narrated experiences. We argue that applying a narrative-discursive approach to African feminist theorising enables understandings of African womxn’s experiences and resistances which are informed by definitions of racial identity and culture, womxnhood, and social reality as dynamic social concepts and practices. These kinds of understandings facilitate community psychology interventions that are relevant and ‘emancipatory’ as they stem from the multiplicity of participants’ narrated experiences and the social and discursive power relations implicit in these narratives.
- Full Text:
- Date Issued: 2019
- Authors: Mavuso, Jabulile M-J J , Chiweshe, Malvern T , Macleod, Catriona I
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434131 , vital:73033 , ISBN 978-3-030-20000-8 , https://doi.org/10.1007/978-3-030-20001-5_2
- Description: A decolonial feminist community psychology approach understands individual experience as being embedded in, enabled and shaped by discursive and social power relations, and that transformative change is only possible through this contextualised understanding of individual experiences. African feminisms have been concerned with the challenging task of exploring and producing accounts of the complexity and multiplicity in womxn’s (and mxn’s) experiences of localised, multiple forms of oppression and the resistances enacted against them. We demonstrate how the utilisation of a narrative-discursive method in research that is guided by poststructural and postcolonial African feminist theorising may be a useful tool in realising the goals and aims of both decolonial feminist community psychology, and African feminist theorising. In this chapter, we draw on research that explored Zimbabwean womxn’s narratives of abortion decision-making and South African womxn’s and healthcare providers’ narratives of their experiences of the pre-abortion counselling healthcare encounter in the Eastern Cape public health sector. We also draw on our own intervention, a policy brief that had been developed into pre-abortion counselling guidelines which were informed by womxn’s narrated experiences. We argue that applying a narrative-discursive approach to African feminist theorising enables understandings of African womxn’s experiences and resistances which are informed by definitions of racial identity and culture, womxnhood, and social reality as dynamic social concepts and practices. These kinds of understandings facilitate community psychology interventions that are relevant and ‘emancipatory’ as they stem from the multiplicity of participants’ narrated experiences and the social and discursive power relations implicit in these narratives.
- Full Text:
- Date Issued: 2019
Participatory mapping in a developing country context: Lessons from South Africa
- Weyer, Dylan J, Bezerra, Joana C, de Vos, Alta
- Authors: Weyer, Dylan J , Bezerra, Joana C , de Vos, Alta
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416333 , vital:71340 , xlink:href="https://doi.org/10.3390/land8090134"
- Description: Digital participatory mapping improves accessibility to spatial information and the way in which knowledge is co-constructed and landscapes co-managed with impoverished communities. However, many unintended consequences for social and epistemic justice may be exacerbated in developing country contexts. Two South African case studies incorporating Direct-to-Digital participatory mapping in marginalized communities to inform land-use decision-making, and the ethical challenges of adopting this method are discussed. Understanding the past and present context of the site and the power dynamics at play is critical to develop trust and manage expectations among research participants. When employing unfamiliar technology, disparate literacy levels and language barriers create challenges for ensuring participants understand the risks of their involvement and recognize their rights. The logistics of using this approach in remote areas with poor infrastructure and deciding how best to leave the participants with the maps they have co-produced in an accessible format present further challenges. Overcoming these can however offer opportunity for redressing past injustices and empowering marginalized communities with a voice in decisions that affect their livelihoods.
- Full Text:
- Date Issued: 2019
- Authors: Weyer, Dylan J , Bezerra, Joana C , de Vos, Alta
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416333 , vital:71340 , xlink:href="https://doi.org/10.3390/land8090134"
- Description: Digital participatory mapping improves accessibility to spatial information and the way in which knowledge is co-constructed and landscapes co-managed with impoverished communities. However, many unintended consequences for social and epistemic justice may be exacerbated in developing country contexts. Two South African case studies incorporating Direct-to-Digital participatory mapping in marginalized communities to inform land-use decision-making, and the ethical challenges of adopting this method are discussed. Understanding the past and present context of the site and the power dynamics at play is critical to develop trust and manage expectations among research participants. When employing unfamiliar technology, disparate literacy levels and language barriers create challenges for ensuring participants understand the risks of their involvement and recognize their rights. The logistics of using this approach in remote areas with poor infrastructure and deciding how best to leave the participants with the maps they have co-produced in an accessible format present further challenges. Overcoming these can however offer opportunity for redressing past injustices and empowering marginalized communities with a voice in decisions that affect their livelihoods.
- Full Text:
- Date Issued: 2019
Pereskiophaga brasiliensis, a natural enemy of the invasive alien cactus Pereskia aculeata, is not suitably host specific for biological control in South Africa
- Paterson, Iain D, Muskett, Phillippa C, Mdodana, LL, Vitorino, Marcello D
- Authors: Paterson, Iain D , Muskett, Phillippa C , Mdodana, LL , Vitorino, Marcello D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417498 , vital:71458 , xlink:href="https://doi.org/10.1080/09583157.2019.1581132"
- Description: The stem-mining weevil, Pereskiophaga brasiliensis, was a candidate biological control agent for the invasive cactus Pereskia aculeata in South Africa. In host specificity trials, it developed on two indigenous test plant species under choice and no-choice conditions. Pereskiophaga brasiliensis is therefore not suitably host specific for release in South Africa.
- Full Text:
- Date Issued: 2019
- Authors: Paterson, Iain D , Muskett, Phillippa C , Mdodana, LL , Vitorino, Marcello D
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417498 , vital:71458 , xlink:href="https://doi.org/10.1080/09583157.2019.1581132"
- Description: The stem-mining weevil, Pereskiophaga brasiliensis, was a candidate biological control agent for the invasive cactus Pereskia aculeata in South Africa. In host specificity trials, it developed on two indigenous test plant species under choice and no-choice conditions. Pereskiophaga brasiliensis is therefore not suitably host specific for release in South Africa.
- Full Text:
- Date Issued: 2019
Photo-physicochemical properties and in vitro photodynamic therapy activity of morpholine-substituted Zinc (II)-Phthalocyanines π-π stacked on biotinylated graphene quantum dots
- Nene, Lindokuhle, Managa, Muthumuni, Nyokong, Tebello
- Authors: Nene, Lindokuhle , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186993 , vital:44554 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.03.002"
- Description: Two morpholine-substituted Zn(II) phthalocyanines, complex 4 and the cationic 5, were synthesized and conjugated to graphene quantum dots (GQDs) and biotinylated GQDs (GQDs-biotin) by non-covalent π-π interactions. The GQDs-biotin are prepared as potential nanoparticle-based Pc delivery vector combined with a receptor-mediated transport system using biotin. The photo-physicochemical properties of the Pc complexes and their corresponding conjugates were studied. Upon conjugation, the fluorescence quantum yields decrease for 4 and 5, however, the triplet quantum yields were increased for the conjugates. All samples demonstrated singlet oxygen generation. For conjugated complexes, the singlet quantum yields decreased due to the screening effect in some cases. An increase in the photodynamic therapy activities upon quaternization was observed for the conjugates, with the cell viability decreasing from 66.2% to 51.2% after treatment for 4-GQDs and 5-GQDs, respectively. A relatively better performance was also observed for the cationic complex in combination with the biotin functionalized GQDs, 5-GQDs-biotin, where the cell viability was 34.9% after treatment. Moreover, the cellular uptake of 5-GQDs-biotin over 24 h was relatively higher compared to Pc complex alone and other PcsGQDs conjugates.
- Full Text:
- Date Issued: 2019
- Authors: Nene, Lindokuhle , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186993 , vital:44554 , xlink:href="https://doi.org/10.1016/j.dyepig.2019.03.002"
- Description: Two morpholine-substituted Zn(II) phthalocyanines, complex 4 and the cationic 5, were synthesized and conjugated to graphene quantum dots (GQDs) and biotinylated GQDs (GQDs-biotin) by non-covalent π-π interactions. The GQDs-biotin are prepared as potential nanoparticle-based Pc delivery vector combined with a receptor-mediated transport system using biotin. The photo-physicochemical properties of the Pc complexes and their corresponding conjugates were studied. Upon conjugation, the fluorescence quantum yields decrease for 4 and 5, however, the triplet quantum yields were increased for the conjugates. All samples demonstrated singlet oxygen generation. For conjugated complexes, the singlet quantum yields decreased due to the screening effect in some cases. An increase in the photodynamic therapy activities upon quaternization was observed for the conjugates, with the cell viability decreasing from 66.2% to 51.2% after treatment for 4-GQDs and 5-GQDs, respectively. A relatively better performance was also observed for the cationic complex in combination with the biotin functionalized GQDs, 5-GQDs-biotin, where the cell viability was 34.9% after treatment. Moreover, the cellular uptake of 5-GQDs-biotin over 24 h was relatively higher compared to Pc complex alone and other PcsGQDs conjugates.
- Full Text:
- Date Issued: 2019
Photophysical and enhanced nonlinear optical response in asymmetric benzothiazole substituted phthalocyanine covalently linked to semiconductor quantum dots
- Nwaji, Njemuwa, Dingiswayo, Somila, Mack, John, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Dingiswayo, Somila , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187851 , vital:44703 , xlink:href="https://doi.org/10.1016/j.saa.2018.06.098"
- Description: The synthesis of asymmetric benzothiazole substituted phthalocyanines (complexes 3 to 5) and their covalent attachment to glutathione (GSH) functionalized quantum dots (QDs) are reported in this work. Additionally, their photophysical and nonlinear optical properties were investigated. A decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield was observed when the complexes were covalently linked to glutathione (GSH) functionalized cadmium telluride (CdTe) quantum dots. Reverse saturable absorption was found to be predominantly dominated by excited state absorption. The observed limiting threshold values range from 0.29–0.75 J/cm2.
- Full Text:
- Date Issued: 2019
- Authors: Nwaji, Njemuwa , Dingiswayo, Somila , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187851 , vital:44703 , xlink:href="https://doi.org/10.1016/j.saa.2018.06.098"
- Description: The synthesis of asymmetric benzothiazole substituted phthalocyanines (complexes 3 to 5) and their covalent attachment to glutathione (GSH) functionalized quantum dots (QDs) are reported in this work. Additionally, their photophysical and nonlinear optical properties were investigated. A decrease in the fluorescence quantum yield with corresponding increase in the triplet quantum yield was observed when the complexes were covalently linked to glutathione (GSH) functionalized cadmium telluride (CdTe) quantum dots. Reverse saturable absorption was found to be predominantly dominated by excited state absorption. The observed limiting threshold values range from 0.29–0.75 J/cm2.
- Full Text:
- Date Issued: 2019
Photophysical and nonlinear optical characteristics of pyridyl substituted phthalocyanine-detonation nanodiamond conjugated systems in solution
- Matshitse, Refilwe, Khene, Samson M, Nyokong, Tebello
- Authors: Matshitse, Refilwe , Khene, Samson M , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187079 , vital:44563 , xlink:href="https://doi.org/10.1016/j.diamond.2019.03.013"
- Description: In this study photophysical, nonlinear absorption and optical limiting properties of detonation nanodiamonds (DNDs)-phthalocyanine nanoconjugate systems containing: 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyaninato (H2TPPc), 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyanato zinc(II) (ZnTPPc) and 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyanato silicon(IV) hydroxide (Si(OH)2TPPc), were investigated in dimethylsulfoxide solution. Pcs were non-covalently linked to nanondiamonds (also covalently linked for Si(OH)2TPPc) and investigated using 532 nm laser excitation at 10 ns pulses for their optical limiting properties. Complexes that have higher triplet state absorption also possessed enhanced nonlinear optical behaviour following reverse saturable absorption mechanism. Superior optical performance is observed when the Pcs had a central metal with axial ligands conjugated to DNDs in solution. Nanoconjugate of DNDs-Si(OH)2TPPc and respective Pc in solution gave the highest imaginary third-order susceptibility (Im[X(3)]) and hyperpolarizability (γ) at 2.91 × 10−8 and 3.17 × 10−8 esu and 3.88 × 10−28 and 4.22 × 10−28 esu, respectively, with Ilim value of 0.47 and 0.39 J·cm−2.
- Full Text:
- Date Issued: 2019
- Authors: Matshitse, Refilwe , Khene, Samson M , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187079 , vital:44563 , xlink:href="https://doi.org/10.1016/j.diamond.2019.03.013"
- Description: In this study photophysical, nonlinear absorption and optical limiting properties of detonation nanodiamonds (DNDs)-phthalocyanine nanoconjugate systems containing: 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyaninato (H2TPPc), 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyanato zinc(II) (ZnTPPc) and 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyanato silicon(IV) hydroxide (Si(OH)2TPPc), were investigated in dimethylsulfoxide solution. Pcs were non-covalently linked to nanondiamonds (also covalently linked for Si(OH)2TPPc) and investigated using 532 nm laser excitation at 10 ns pulses for their optical limiting properties. Complexes that have higher triplet state absorption also possessed enhanced nonlinear optical behaviour following reverse saturable absorption mechanism. Superior optical performance is observed when the Pcs had a central metal with axial ligands conjugated to DNDs in solution. Nanoconjugate of DNDs-Si(OH)2TPPc and respective Pc in solution gave the highest imaginary third-order susceptibility (Im[X(3)]) and hyperpolarizability (γ) at 2.91 × 10−8 and 3.17 × 10−8 esu and 3.88 × 10−28 and 4.22 × 10−28 esu, respectively, with Ilim value of 0.47 and 0.39 J·cm−2.
- Full Text:
- Date Issued: 2019
Photophysical properties and photodynamic therapy activities of detonated nanodiamonds-BODIPY-phthalocyanines nanoassemblies
- Matshitse, Refilwe, Ngoy, Bokolombe P, Managa, Muthumuni, Mack, John, Nyokong, Tebello
- Authors: Matshitse, Refilwe , Ngoy, Bokolombe P , Managa, Muthumuni , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186981 , vital:44553 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.03.007"
- Description: This work reports on the synthesis of nanoassemblies of supramolecular hybrids containing detonated nanodiamonds (DNDs) covalently linked to halogenated BODIPY (DNDs-BODIPY) by an amide bond, followed by π–π stacking of 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) on the DNDs-BODIPY conjugate, to form nanoassembly represented as ZnTPPcQ-DNDs-BODIPY. ZnTPPcQ-DNDs-BODIPY has a higher singlet oxygen quantum yield of 0.50 in water. Therefore, the construction of a three component photodynamic therapy agent (ZnTPPcQ-DNDs-BODIPY) as a single photosentisiser improved singlet quantum yields of the Pc. Zeta potential studies of ZnTPPcQ-DNDs-BODIPY under various temperatures, concentrations and pH conditions, showed the conjugate is more stable at pHs 2, 4 and 7 and at high concentrations (50 μg/mL) and temperatures (80 °C). ZnTPPcQ-DNDs-BODIPY showed high photodynamic therapy (PDT) activity with a low MCF-7 cell viability of 21 ± 5% when compared to 31 ± 2%, 30 ± 2% and 28 ± 2% cell viability at the highest tested concentration of 50 μg/mL for DNDs, ZnTPPcQ-DND and DNDs-BODIPY, respectively.
- Full Text:
- Date Issued: 2019
- Authors: Matshitse, Refilwe , Ngoy, Bokolombe P , Managa, Muthumuni , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186981 , vital:44553 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.03.007"
- Description: This work reports on the synthesis of nanoassemblies of supramolecular hybrids containing detonated nanodiamonds (DNDs) covalently linked to halogenated BODIPY (DNDs-BODIPY) by an amide bond, followed by π–π stacking of 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) on the DNDs-BODIPY conjugate, to form nanoassembly represented as ZnTPPcQ-DNDs-BODIPY. ZnTPPcQ-DNDs-BODIPY has a higher singlet oxygen quantum yield of 0.50 in water. Therefore, the construction of a three component photodynamic therapy agent (ZnTPPcQ-DNDs-BODIPY) as a single photosentisiser improved singlet quantum yields of the Pc. Zeta potential studies of ZnTPPcQ-DNDs-BODIPY under various temperatures, concentrations and pH conditions, showed the conjugate is more stable at pHs 2, 4 and 7 and at high concentrations (50 μg/mL) and temperatures (80 °C). ZnTPPcQ-DNDs-BODIPY showed high photodynamic therapy (PDT) activity with a low MCF-7 cell viability of 21 ± 5% when compared to 31 ± 2%, 30 ± 2% and 28 ± 2% cell viability at the highest tested concentration of 50 μg/mL for DNDs, ZnTPPcQ-DND and DNDs-BODIPY, respectively.
- Full Text:
- Date Issued: 2019
Photophysical properties and photodynamic therapy activity of a meso-tetra (4-carboxyphenyl) porphyrin tetramethyl ester–graphene quantum dot conjugate
- Managa, Muthumuni, Ngoy, Bokolombe P, Nyokong, Tebello
- Authors: Managa, Muthumuni , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187533 , vital:44669 , xlink:href="https://doi.org/10.1039/C8NJ06175K"
- Description: Novel meso-tetra(4-carboxyphenyl)porphyrin tetramethyl ester metal derivatives were synthesised and characterized. These derivatives were interacted with graphene quantum dots (GDQs). Spectroscopic evidence that was obtained showed that the resultant conjugates were stable due to the strong π–π stacking interaction between the GQDs and the porphyrins. The fluorescence and singlet oxygen generating behaviour of the porphyrins and the nanoconjugates were investigated following incorporation. The dark toxicity and photodynamic therapy activities of the porphyrins and the nanoconjugates were successfully studied using MCF-7 breast cancer cells. Cell viability for the dark toxicity was more than 90% for all complexes. The PDT activities at the highest concentration of 120 μg ml−1 showed a decrease in cell viability down to 15.2% for the GaClTMPP–GQDs.
- Full Text:
- Date Issued: 2019
- Authors: Managa, Muthumuni , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187533 , vital:44669 , xlink:href="https://doi.org/10.1039/C8NJ06175K"
- Description: Novel meso-tetra(4-carboxyphenyl)porphyrin tetramethyl ester metal derivatives were synthesised and characterized. These derivatives were interacted with graphene quantum dots (GDQs). Spectroscopic evidence that was obtained showed that the resultant conjugates were stable due to the strong π–π stacking interaction between the GQDs and the porphyrins. The fluorescence and singlet oxygen generating behaviour of the porphyrins and the nanoconjugates were investigated following incorporation. The dark toxicity and photodynamic therapy activities of the porphyrins and the nanoconjugates were successfully studied using MCF-7 breast cancer cells. Cell viability for the dark toxicity was more than 90% for all complexes. The PDT activities at the highest concentration of 120 μg ml−1 showed a decrease in cell viability down to 15.2% for the GaClTMPP–GQDs.
- Full Text:
- Date Issued: 2019
Photophysicochemical and photodynamic therapy properties of metallophthalocyanines linked to gold speckled silica nanoparticles
- Dube, Edith, Oluwole, David O, Niemuwa, Nwaji, Prinsloo, Earl, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Niemuwa, Nwaji , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187472 , vital:44657 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.01.019"
- Description: This work reports on the linkage of 2(3),9(10),16(17),23(24) tetrakis [(benzo[d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (1) and indium(III) chloride (2) to gold speckled silica (GSS) nanoparticles via gold to sulphur (Au-S) and gold to nitrogen (Au-N) self-assembly to form the conjugates: 1-GSS and 2-GSS. The formed conjugates were characterized using microscopic and spectroscopic techniques, and the photophysicochemical properties and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7 cells) were studied. The conjugates afforded decrease in fluorescence quantum yields with corresponding increase in triplet and singlet oxygen quantum yields when compared to phthalocyanines alone. Singlet oxygen is cytotoxic to cancer cells hence it is important for PDT. The in vitro dark toxicity of complex 2 and 2-GSS against MCF–7 cells showed ≥93% viable cells within concentration ranges of 10–160 μg/mL. 2–GSS showed enhanced PDT activity with less than 50% viable cells at 80 μg/mL as compared to 2 and GSS alone which showed > 60% viable cells within 10–160 μg/mL. The observed improvements in the PDT activity of 2-GSS could be attributed to the high singlet oxygen generation of 2-GSS compared to 2 alone in addition to the phototoxicity of GSS.
- Full Text:
- Date Issued: 2019
- Authors: Dube, Edith , Oluwole, David O , Niemuwa, Nwaji , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187472 , vital:44657 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.01.019"
- Description: This work reports on the linkage of 2(3),9(10),16(17),23(24) tetrakis [(benzo[d]thiazol-2-yl phenoxy) phthalocyaninato] zinc(II) (1) and indium(III) chloride (2) to gold speckled silica (GSS) nanoparticles via gold to sulphur (Au-S) and gold to nitrogen (Au-N) self-assembly to form the conjugates: 1-GSS and 2-GSS. The formed conjugates were characterized using microscopic and spectroscopic techniques, and the photophysicochemical properties and photodynamic therapy (PDT) activity against human breast adenocarcinoma cell line (MCF-7 cells) were studied. The conjugates afforded decrease in fluorescence quantum yields with corresponding increase in triplet and singlet oxygen quantum yields when compared to phthalocyanines alone. Singlet oxygen is cytotoxic to cancer cells hence it is important for PDT. The in vitro dark toxicity of complex 2 and 2-GSS against MCF–7 cells showed ≥93% viable cells within concentration ranges of 10–160 μg/mL. 2–GSS showed enhanced PDT activity with less than 50% viable cells at 80 μg/mL as compared to 2 and GSS alone which showed > 60% viable cells within 10–160 μg/mL. The observed improvements in the PDT activity of 2-GSS could be attributed to the high singlet oxygen generation of 2-GSS compared to 2 alone in addition to the phototoxicity of GSS.
- Full Text:
- Date Issued: 2019
Physicochemical and antimicrobial photodynamic chemotherapy (against E. coli) by indium phthalocyanines in the presence of silver–iron bimetallic nanoparticles
- Magadla, Aviwe, Oluwole, David O, Managa, Muthumuni, Nyokong, Tebello
- Authors: Magadla, Aviwe , Oluwole, David O , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187091 , vital:44564 , xlink:href="https://doi.org/10.1016/j.poly.2019.01.032"
- Description: In this work, Schiff base indium phthalocyanines: In–Cl tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine (complex 1b) and In–Cl tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine (complex 2b) are synthesized from tetra amino and tetra phenoxy amino phthalocyanines, respectively. These complexes were further quartenised with 1,3-propanesultone to form zwitterionic complexes 1 and 2, respectively. Silver–iron dimers (Ag–Fe3O4) and silver-iron core shell (Ag@Fe3O4) nanoparticles (NPs) were linked to the synthesised complexes. The photophysical and photochemical behaviour of the complexes and their conjugates with NPs were investigated in dimethyl sulfoxide. Complexes 2 and 2b and their conjugates were then used for photodynamic antimicrobial chemotherapy on Escherichia coli. The zwitter ionic photosensitiser 2 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2019
- Authors: Magadla, Aviwe , Oluwole, David O , Managa, Muthumuni , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187091 , vital:44564 , xlink:href="https://doi.org/10.1016/j.poly.2019.01.032"
- Description: In this work, Schiff base indium phthalocyanines: In–Cl tetrakis N,N-dimethyl-4-(methylimino) phthalocyanine (complex 1b) and In–Cl tetrakis phenoxy N,N-dimethyl-4-(methylimino) phthalocyanine (complex 2b) are synthesized from tetra amino and tetra phenoxy amino phthalocyanines, respectively. These complexes were further quartenised with 1,3-propanesultone to form zwitterionic complexes 1 and 2, respectively. Silver–iron dimers (Ag–Fe3O4) and silver-iron core shell (Ag@Fe3O4) nanoparticles (NPs) were linked to the synthesised complexes. The photophysical and photochemical behaviour of the complexes and their conjugates with NPs were investigated in dimethyl sulfoxide. Complexes 2 and 2b and their conjugates were then used for photodynamic antimicrobial chemotherapy on Escherichia coli. The zwitter ionic photosensitiser 2 and its conjugates showed better efficiency for photodynamic antimicrobial chemotherapy compared to their neutral counterparts.
- Full Text:
- Date Issued: 2019
Physicochemical and photodynamic antimicrobial chemotherapy activity of morpholine-substituted phthalocyanines: Effect of point of substitution and central metal
- Sindelo, Azole, Kobayashi, Nagao, Kimura, Mutsumi, Nyokong, Tebello
- Authors: Sindelo, Azole , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187438 , vital:44652 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.01.025"
- Description: In this study, novel metal-free, zinc and indium 1(4),8(11),15(18),22(25)-tetramorpholine (1a, 2a, 3a respectively) and 2(3), 9(10), 16(17),23(24)-tetramorpholine (1b, 2b, 3b respectively) phthalocyanines were synthesized and complexes 2 and 3 were quaternized. The photophysical and photochemical properties were investigated in dimethylsulfoxide. The non-peripherally substituted phthalocyanines generated higher singlet oxygen than the peripherally substituted phthalocyanines. Photodynamic antimicrobial chemotherapy activities towards inactivation of Escherichia coli, Staphylococcus aureus and Candida albican were evaluated, where all the quaternized Pcs showed total elimination of the micro-organism with log reductions greater than 9. Though the neutral Pcs had log reductions less than 2, for C. albican the percentage reduction was 68.5% for 2b showing the antifungal properties of the morpholine group.
- Full Text:
- Date Issued: 2019
- Authors: Sindelo, Azole , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187438 , vital:44652 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.01.025"
- Description: In this study, novel metal-free, zinc and indium 1(4),8(11),15(18),22(25)-tetramorpholine (1a, 2a, 3a respectively) and 2(3), 9(10), 16(17),23(24)-tetramorpholine (1b, 2b, 3b respectively) phthalocyanines were synthesized and complexes 2 and 3 were quaternized. The photophysical and photochemical properties were investigated in dimethylsulfoxide. The non-peripherally substituted phthalocyanines generated higher singlet oxygen than the peripherally substituted phthalocyanines. Photodynamic antimicrobial chemotherapy activities towards inactivation of Escherichia coli, Staphylococcus aureus and Candida albican were evaluated, where all the quaternized Pcs showed total elimination of the micro-organism with log reductions greater than 9. Though the neutral Pcs had log reductions less than 2, for C. albican the percentage reduction was 68.5% for 2b showing the antifungal properties of the morpholine group.
- Full Text:
- Date Issued: 2019
Phytochemical, anti-inflammatory and anti-trypanosomal properties of Anthocleista vogelii Planch (Loganiaceae) stem bark
- Eze, Fabian I, Siwe-Noundou, Xavier, Osadebe, Patience, Krause, Rui W M
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Osadebe, Patience , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194059 , vital:45419 , xlink:href="https://doi.org/10.1016/j.jep.2019.111851"
- Description: Ethnopharmacological relevance: Anthocleista vogelii Planch (Loganiaceae) is used in African Traditional Medicine for the treatment of pain and inflammatory disorders as well as sleeping sickness. Aim of the study: To determine the in vivo anti-inflammatory and in vitro anti-trypanosomal activities of the extracts of A. vogelii stem bark and identify the phytochemical classes of the fractions responsible for the activities. Materials and methods: The in vivo anti-inflammatory activity of the extracts was evaluated using the egg albumin-induced rat paw oedema model while the in vitro anti-trypanosomal activity was assessed on Trypanosoma brucei brucei. The in vitro cytotoxicity was assessed on HeLa (human cervix adenocarcinoma) cell line. Results: The methanolic extract of A. vogelii stem bark, with 11.2% yield, gave LD50 > 5000 mg/kg. The n-hexane fraction of the extract contains steroids, terpenes and fatty acids and yielded non-cytotoxic terpenoidal column fraction with anti-trypanosomal IC50 of 3.0 μg/mL. The ethylacetate fraction at 100 mg/kg dose significantly (p less than 0.05) provoked 37.8, 62.5 and 69.7% inhibition of oedema induced by egg-albumin at the second, fourth and sixth hours respectively. Conclusion: The study demonstrated that the anti-inflammatory and anti-trypanosomal activities of A. vogelii are probably due to non-cytotoxic terpenoids and validated the traditional use of A. vogelii in the treatment of inflammation and sleeping sickness.
- Full Text:
- Date Issued: 2019
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Osadebe, Patience , Krause, Rui W M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194059 , vital:45419 , xlink:href="https://doi.org/10.1016/j.jep.2019.111851"
- Description: Ethnopharmacological relevance: Anthocleista vogelii Planch (Loganiaceae) is used in African Traditional Medicine for the treatment of pain and inflammatory disorders as well as sleeping sickness. Aim of the study: To determine the in vivo anti-inflammatory and in vitro anti-trypanosomal activities of the extracts of A. vogelii stem bark and identify the phytochemical classes of the fractions responsible for the activities. Materials and methods: The in vivo anti-inflammatory activity of the extracts was evaluated using the egg albumin-induced rat paw oedema model while the in vitro anti-trypanosomal activity was assessed on Trypanosoma brucei brucei. The in vitro cytotoxicity was assessed on HeLa (human cervix adenocarcinoma) cell line. Results: The methanolic extract of A. vogelii stem bark, with 11.2% yield, gave LD50 > 5000 mg/kg. The n-hexane fraction of the extract contains steroids, terpenes and fatty acids and yielded non-cytotoxic terpenoidal column fraction with anti-trypanosomal IC50 of 3.0 μg/mL. The ethylacetate fraction at 100 mg/kg dose significantly (p less than 0.05) provoked 37.8, 62.5 and 69.7% inhibition of oedema induced by egg-albumin at the second, fourth and sixth hours respectively. Conclusion: The study demonstrated that the anti-inflammatory and anti-trypanosomal activities of A. vogelii are probably due to non-cytotoxic terpenoids and validated the traditional use of A. vogelii in the treatment of inflammation and sleeping sickness.
- Full Text:
- Date Issued: 2019
Poverty reduction strategies and non-timber forest products
- Pullanikkatil, Deepa, Shackleton, Charlie M
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433583 , vital:72985 , ISBN 978-3-319-75580-9 , https://link.springer.com/chapter/10.1007/978-3-319-75580-9_1
- Description: The first of the 17 Global Goals that make up the 2030 Agenda for Sustainable Development is to end poverty in all its forms everywhere. Although the numbers of poor people in the world has declined over the last few decades, it is still alarmingly high, being approximately 770 million in 2013 (Fig. 1) (World Bank in Understanding Poverty 2017). Currently the majority of the world’s poor live in rural areas, and their livelihoods are dominated by land-based activities including gathering of Non-Timber Forest Products (NTFPs). There were rela tively few studies offering more socially orientated perspectives and insights on the links between NTFP use, dependency and poverty. The ordinary people using NTFPs, their reasons for doing so and their experiences are given in this book.
- Full Text:
- Date Issued: 2019
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433583 , vital:72985 , ISBN 978-3-319-75580-9 , https://link.springer.com/chapter/10.1007/978-3-319-75580-9_1
- Description: The first of the 17 Global Goals that make up the 2030 Agenda for Sustainable Development is to end poverty in all its forms everywhere. Although the numbers of poor people in the world has declined over the last few decades, it is still alarmingly high, being approximately 770 million in 2013 (Fig. 1) (World Bank in Understanding Poverty 2017). Currently the majority of the world’s poor live in rural areas, and their livelihoods are dominated by land-based activities including gathering of Non-Timber Forest Products (NTFPs). There were rela tively few studies offering more socially orientated perspectives and insights on the links between NTFP use, dependency and poverty. The ordinary people using NTFPs, their reasons for doing so and their experiences are given in this book.
- Full Text:
- Date Issued: 2019
Poverty reduction through non-timber forest products
- Pullanikkatil, Deepa, Shackleton, Charlie M
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/433598 , vital:72986 , ISBN 978-3-319-75580-9 , https://doi.org/10.1007/978-3-319-75580-9
- Description: This book narrates personal stories of people from around the world who have used natural products, in particular Non Timber Forest Products (NTFPs) as a means to come out of poverty. Ending poverty remains a major worldwide challenge and is the number one goal under the UN Sustainable Development Goals. The book fills an important knowledge gap; that of personal stories of NTFP users. This has not been part of past publications on NTFPs which tend to focus on statistics and analysis of numbers, thus, the human faces of NTFP users are missing. Narrative stories provide a wealth of data about people and their experiences rather than aggregated classifications, categories and characteristics of poverty. The objective of this book is to illustrate the poverty alleviation potential of NTFPs through documenting the personal life stories of individuals and households that lifted themselves out of poverty through trade of NTFPs. This book is for all who are interested in poverty alleviation and NTFPs.
- Full Text:
- Date Issued: 2019
- Authors: Pullanikkatil, Deepa , Shackleton, Charlie M
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/433598 , vital:72986 , ISBN 978-3-319-75580-9 , https://doi.org/10.1007/978-3-319-75580-9
- Description: This book narrates personal stories of people from around the world who have used natural products, in particular Non Timber Forest Products (NTFPs) as a means to come out of poverty. Ending poverty remains a major worldwide challenge and is the number one goal under the UN Sustainable Development Goals. The book fills an important knowledge gap; that of personal stories of NTFP users. This has not been part of past publications on NTFPs which tend to focus on statistics and analysis of numbers, thus, the human faces of NTFP users are missing. Narrative stories provide a wealth of data about people and their experiences rather than aggregated classifications, categories and characteristics of poverty. The objective of this book is to illustrate the poverty alleviation potential of NTFPs through documenting the personal life stories of individuals and households that lifted themselves out of poverty through trade of NTFPs. This book is for all who are interested in poverty alleviation and NTFPs.
- Full Text:
- Date Issued: 2019
Pregnancy Decision Making: Abortion and Adoption
- Mavuso, Jabulile M-J J, Macleod, Catriona I
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434145 , vital:73034 , ISBN 9781119161899 , https://onlinelibrary.wiley.com/doi/book/10.1002/9781119171492
- Description: Pregnancy decision making encompasses a large range of interactions, including decisions and actions to avoid pregnancy or to become pregnant. This entry addresses the question of decision making regarding the outcome of a pregnancy: abortion or taking the pregnancy to term, with the latter resulting in parenting or adoption placement. Adolescents' pregnancy decision making has been a special area of focus for some decades now, particularly regarding whether adolescents are capable of making termination-of-pregnancy decisions. This entry highlights controversies concerning, first, teenage pregnancy as a social problem; second, risk research that seeks to outline the consequences of various reproductive decisions; third, questions around adolescents' maturity regarding making reproductive decisions; fourth, the reasons provided for various reproductive decisions; and, finally, issues surrounding the autonomy of young pregnant women in their reproductive decisions.
- Full Text:
- Date Issued: 2019
- Authors: Mavuso, Jabulile M-J J , Macleod, Catriona I
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434145 , vital:73034 , ISBN 9781119161899 , https://onlinelibrary.wiley.com/doi/book/10.1002/9781119171492
- Description: Pregnancy decision making encompasses a large range of interactions, including decisions and actions to avoid pregnancy or to become pregnant. This entry addresses the question of decision making regarding the outcome of a pregnancy: abortion or taking the pregnancy to term, with the latter resulting in parenting or adoption placement. Adolescents' pregnancy decision making has been a special area of focus for some decades now, particularly regarding whether adolescents are capable of making termination-of-pregnancy decisions. This entry highlights controversies concerning, first, teenage pregnancy as a social problem; second, risk research that seeks to outline the consequences of various reproductive decisions; third, questions around adolescents' maturity regarding making reproductive decisions; fourth, the reasons provided for various reproductive decisions; and, finally, issues surrounding the autonomy of young pregnant women in their reproductive decisions.
- Full Text:
- Date Issued: 2019
Preparation of NIR absorbing axial substituted tin (iv) porphyrins and their photocytotoxic properties
- Babu, Balaji, Amuhaya, Edith K, Oluwole, David O, Prinsloo, Earl, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Amuhaya, Edith K , Oluwole, David O , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234592 , vital:50211 , xlink:href="https://doi.org/10.1039/C8MD00373D"
- Description: Sn(IV) porphyrins ([Sn(IV)TTP(3PyO)2] (5) and [Sn(IV)TPP(3PyO)2] (6) [tetrathienylporphyrin (TTP), tetraphenylporphyrin (TPP), and pyridyloxy (PyO)]) were prepared and characterized and their photocytotoxicity upon irradiation with 625 nm light has been studied. The presence of the 3PyO axial ligands was found to limit the aggregation and enhance the solubility of 5 and 6 in DMF/H2O (1 : 1). The photophysical properties and photodynamic therapy (PDT) activity of the meso-2-thienyl and meso-phenyl-substituted Sn(IV) porphyrins are compared. 5 and 6 were found to be photocytotoxic in MCF-7 cancer cells when irradiated with a Thorlabs M625L3 LED at 625 nm but remained nontoxic in the dark. The PDT activity of Sn(IV) meso-tetra-2-thienylporphyrin 5 was found to be significantly enhanced relative to its analogous tetraphenylporphyrin 6. There is a marked red-shift of the Q00 band of 5 into the therapeutic window due to the meso-2-thienyl rings, and 5 has an unusually high singlet oxygen quantum yield value of 0.83 in DMF. The results demonstrate that readily synthesized axially ligated Sn(IV) meso-arylporphyrins are potentially suitable for use as singlet oxygen photosensitizers in biomedical applications and merit further in depth investigation in this context.
- Full Text:
- Date Issued: 2019
- Authors: Babu, Balaji , Amuhaya, Edith K , Oluwole, David O , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234592 , vital:50211 , xlink:href="https://doi.org/10.1039/C8MD00373D"
- Description: Sn(IV) porphyrins ([Sn(IV)TTP(3PyO)2] (5) and [Sn(IV)TPP(3PyO)2] (6) [tetrathienylporphyrin (TTP), tetraphenylporphyrin (TPP), and pyridyloxy (PyO)]) were prepared and characterized and their photocytotoxicity upon irradiation with 625 nm light has been studied. The presence of the 3PyO axial ligands was found to limit the aggregation and enhance the solubility of 5 and 6 in DMF/H2O (1 : 1). The photophysical properties and photodynamic therapy (PDT) activity of the meso-2-thienyl and meso-phenyl-substituted Sn(IV) porphyrins are compared. 5 and 6 were found to be photocytotoxic in MCF-7 cancer cells when irradiated with a Thorlabs M625L3 LED at 625 nm but remained nontoxic in the dark. The PDT activity of Sn(IV) meso-tetra-2-thienylporphyrin 5 was found to be significantly enhanced relative to its analogous tetraphenylporphyrin 6. There is a marked red-shift of the Q00 band of 5 into the therapeutic window due to the meso-2-thienyl rings, and 5 has an unusually high singlet oxygen quantum yield value of 0.83 in DMF. The results demonstrate that readily synthesized axially ligated Sn(IV) meso-arylporphyrins are potentially suitable for use as singlet oxygen photosensitizers in biomedical applications and merit further in depth investigation in this context.
- Full Text:
- Date Issued: 2019
Privately protected areas provide key opportunities for the regional persistence of large- and medium-sized mammals
- Clements, Hayley S, Kerley, Graham I, Cumming, Graeme S, de Vos, Alta, Cook, Carly N
- Authors: Clements, Hayley S , Kerley, Graham I , Cumming, Graeme S , de Vos, Alta , Cook, Carly N
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416383 , vital:71344 , xlink:href="https://doi.org/10.1111/1365-2664.13300"
- Description: Biodiversity conservation relies heavily on protected areas (PAs). However, in locations that are desirable for agriculture, industry, or human habitation (e.g., low -land habitats on fertile soils, coastal zones), land is often privately owned and state-owned PAs tend to be under-represented. Despite the potentially disproportionate contribution that privately protected areas (PPAs) could make to representing biodiversity and supporting its persistence across regional PA estates, this contribution is poorly understood.
- Full Text:
- Date Issued: 2019
- Authors: Clements, Hayley S , Kerley, Graham I , Cumming, Graeme S , de Vos, Alta , Cook, Carly N
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416383 , vital:71344 , xlink:href="https://doi.org/10.1111/1365-2664.13300"
- Description: Biodiversity conservation relies heavily on protected areas (PAs). However, in locations that are desirable for agriculture, industry, or human habitation (e.g., low -land habitats on fertile soils, coastal zones), land is often privately owned and state-owned PAs tend to be under-represented. Despite the potentially disproportionate contribution that privately protected areas (PPAs) could make to representing biodiversity and supporting its persistence across regional PA estates, this contribution is poorly understood.
- Full Text:
- Date Issued: 2019