Synthesis and characterization of ZnO nanoparticle synthesized by a microwave-assisted combustion method and catalytic activity for the removal of ortho-nitrophenol
- Assi, Navid, Mohammadi, Ali, Sadr Manuchehri, Q, Walker, Roderick B
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
- Authors: Assi, Navid , Mohammadi, Ali , Sadr Manuchehri, Q , Walker, Roderick B
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183850 , vital:44075 , xlink:href="https://doi.org/10.1080/19443994.2014.891083"
- Description: ZnO nanoparticles were manufactured using microwave-assisted combustion. The structural and morphological properties of the nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Photocatalytic degradation of ortho-nitrophenol (O-NP) in aqueous solution using the synthesized nanoparticles was performed under UV–C irradiation and is reported for the first time. The effect of the initial O-NP concentration, amount of photocatalyst, pH, and salt was investigated during photodegradation. Analysis of the degraded samples using HPLC with UV detection revealed that photocatalysis in the presence of ZnO nanoparticles removed 98% of the O-NP in 5 h. In addition, the photocatalytic degradation kinetics of O-NP were studied, and the results suggest that the data are best fitted to pseudo-first-order kinetic and Langmuir–Hinshelwood models.
- Full Text:
- Date Issued: 2015
An integrated framework for assessing coastal community vulnerability across cultures, oceans and scales
- Aswani, Shankar, Howard, J A, Gasalla, Maria A, Jennings, Sarah, Malherbe, W, Martins, I M, Salim Shyam, Van Putten, Ingrid E, Swathilekshmi, P S, Narayanakumar, R, Watmough G R
- Authors: Aswani, Shankar , Howard, J A , Gasalla, Maria A , Jennings, Sarah , Malherbe, W , Martins, I M , Salim Shyam , Van Putten, Ingrid E , Swathilekshmi, P S , Narayanakumar, R , Watmough G R
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421581 , vital:71863 , xlink:href="https://doi.org/10.1080/17565529.2018.1442795"
- Description: Coastal communities are some of the most at-risk populations with respect to climate change impacts. It is therefore important to determine the vulnerability of such communities to co-develop viable adaptation options. Global efforts to address this issue include international scientific projects, such as Global Learning for Local Solutions (GULLS), which focuses on five fast warming regions of the southern hemisphere and aims to provide an understanding of the local scale processes influencing community vulnerability that can then be up-scaled to regional, country and global levels. This paper describes the development of a new social and ecological vulnerability framework which integrates exposure, sensitivity and adaptive capacity with the social livelihoods and food security approaches. It also measures community flexibility to understand better the adaptive capacity of different levels of community organization. The translation of the conceptual framework to an implementable method is described and its application in a number of “hotspot” countries, where ocean waters are warming faster than the rest of the world, is presented. Opportunities for cross-cultural comparisons to uncover similarities and differences in vulnerability and adaptation patterns among the study’s coastal communities, which can provide accelerated learning mechanisms to other coastal regions, are highlighted. The social and ecological framework and the associated survey approach allow for future integration of local-level vulnerability data with ecological and oceanographic models.
- Full Text:
- Date Issued: 2019
- Authors: Aswani, Shankar , Howard, J A , Gasalla, Maria A , Jennings, Sarah , Malherbe, W , Martins, I M , Salim Shyam , Van Putten, Ingrid E , Swathilekshmi, P S , Narayanakumar, R , Watmough G R
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421581 , vital:71863 , xlink:href="https://doi.org/10.1080/17565529.2018.1442795"
- Description: Coastal communities are some of the most at-risk populations with respect to climate change impacts. It is therefore important to determine the vulnerability of such communities to co-develop viable adaptation options. Global efforts to address this issue include international scientific projects, such as Global Learning for Local Solutions (GULLS), which focuses on five fast warming regions of the southern hemisphere and aims to provide an understanding of the local scale processes influencing community vulnerability that can then be up-scaled to regional, country and global levels. This paper describes the development of a new social and ecological vulnerability framework which integrates exposure, sensitivity and adaptive capacity with the social livelihoods and food security approaches. It also measures community flexibility to understand better the adaptive capacity of different levels of community organization. The translation of the conceptual framework to an implementable method is described and its application in a number of “hotspot” countries, where ocean waters are warming faster than the rest of the world, is presented. Opportunities for cross-cultural comparisons to uncover similarities and differences in vulnerability and adaptation patterns among the study’s coastal communities, which can provide accelerated learning mechanisms to other coastal regions, are highlighted. The social and ecological framework and the associated survey approach allow for future integration of local-level vulnerability data with ecological and oceanographic models.
- Full Text:
- Date Issued: 2019
Detecting change in local ecological knowledge: An application of an index of taxonomic distinctness to an ethnoichthyological classification in the Solomon Islands
- Aswani, Shankar, Ferse, Sebastien C, Stäbler, Moritz, Chong-Montenegro, Carolina
- Authors: Aswani, Shankar , Ferse, Sebastien C , Stäbler, Moritz , Chong-Montenegro, Carolina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406521 , vital:70282 , xlink:href="https://doi.org/10.1016/j.ecolind.2020.106865"
- Description: The global accelerating loss of biodiversity is having immediate repercussions for ecosystems and human wellbeing, particularly in areas where people depend intimately on their natural environment for their livelihoods. Dovetailing this loss is the demise of local/traditional knowledge systems resulting from factors such as changing lifestyle and the transformation of local belief systems. While the importance of local ecological knowledge (LEK) for documentation of biodiversity and environmental change and development of management responses is well established, quantitative tools to analyze and systematically compare LEK are scarce. In this research, we analyze the complexity of local ecological knowledge used by respondents to classify locally-recognized marine species. We do so by applying a modified index of taxonomic distinctness to an ethnoichthyological classification in coastal communities in the Solomon Islands. In addition, we assess simple taxonomic diversity (richness in locally-recognized species names) by comparing taxonomies collected in 1992–1995 and 2014–2015. Results indicate that both endogenous (gender, age) and exogenous (proximity to market) factors have discernible effects on folk taxonomic knowledge in the region, with younger respondents and communities closer to a regional market center displaying a significantly lower richness of local species names. Folk taxonomic distinctness was significantly reduced closer to the regional market. The modified index of taxonomic distinctness applied in this research provides a useful tool to explore facets of local ecological knowledge in addition to simple richness of terms, and to compare across different regions and cultural backgrounds. Understanding changes in LEK is important because such knowledge enables communities who are highly dependent on living natural resources to harvest and manage resources more efficiently and also to detect and react to environmental change.
- Full Text:
- Date Issued: 2020
- Authors: Aswani, Shankar , Ferse, Sebastien C , Stäbler, Moritz , Chong-Montenegro, Carolina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406521 , vital:70282 , xlink:href="https://doi.org/10.1016/j.ecolind.2020.106865"
- Description: The global accelerating loss of biodiversity is having immediate repercussions for ecosystems and human wellbeing, particularly in areas where people depend intimately on their natural environment for their livelihoods. Dovetailing this loss is the demise of local/traditional knowledge systems resulting from factors such as changing lifestyle and the transformation of local belief systems. While the importance of local ecological knowledge (LEK) for documentation of biodiversity and environmental change and development of management responses is well established, quantitative tools to analyze and systematically compare LEK are scarce. In this research, we analyze the complexity of local ecological knowledge used by respondents to classify locally-recognized marine species. We do so by applying a modified index of taxonomic distinctness to an ethnoichthyological classification in coastal communities in the Solomon Islands. In addition, we assess simple taxonomic diversity (richness in locally-recognized species names) by comparing taxonomies collected in 1992–1995 and 2014–2015. Results indicate that both endogenous (gender, age) and exogenous (proximity to market) factors have discernible effects on folk taxonomic knowledge in the region, with younger respondents and communities closer to a regional market center displaying a significantly lower richness of local species names. Folk taxonomic distinctness was significantly reduced closer to the regional market. The modified index of taxonomic distinctness applied in this research provides a useful tool to explore facets of local ecological knowledge in addition to simple richness of terms, and to compare across different regions and cultural backgrounds. Understanding changes in LEK is important because such knowledge enables communities who are highly dependent on living natural resources to harvest and manage resources more efficiently and also to detect and react to environmental change.
- Full Text:
- Date Issued: 2020
Design of Realistic Hybrid Marine Resource Management Programs in Oceania
- Aswani, Shankar, Ruddle, Kenneth
- Authors: Aswani, Shankar , Ruddle, Kenneth
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/422721 , vital:71972 , xlink:href="https://doi.org/10.2984/67.3.11"
- Description: This review article synthesizes the authors' several decades of multidisciplinary natural and social science and applied marine resource management experience in the Asia-Pacific region to examine the strengthening of coastal and marine resource management and conservation using alliances between local communities and external institutions. The objective is to assist the design of resource management and conservation programs that enhance the capacity of coastal communities in Oceania to confront both diminishing marine resources and the effects of climate change by providing guidelines for protecting marine biodiversity and vulnerable ecosystem functions. This article describes a management framework that hybridizes local beliefs and institutions expressed in customary management (CM) with such modern management concepts as marine protected areas (MPAs) and ecosystem-based management (EBM). Hybrid management accommodates the social, political, economic, and cultural contexts of Oceanic communities and, compared with recent or conventional management approaches, can therefore better address fundamental local concerns such as coastal degradation, climate change, sea level rise, weak governance, corruption, limited resources and staff to manage and monitor marine resources, and increasing poverty. Research on the hybridization of management systems demonstrates opportunities to establish context-appropriate EBM and/or other managerial arrangements that include terrestrial and adjacent coastal-marine ecosystems. Formal and informal CM systems are widespread in Oceania and in some parts of Southeast Asia, and if appropriate strategies are employed rapid progress toward hybrid CM-EBM could be enabled.
- Full Text:
- Date Issued: 2013
- Authors: Aswani, Shankar , Ruddle, Kenneth
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/422721 , vital:71972 , xlink:href="https://doi.org/10.2984/67.3.11"
- Description: This review article synthesizes the authors' several decades of multidisciplinary natural and social science and applied marine resource management experience in the Asia-Pacific region to examine the strengthening of coastal and marine resource management and conservation using alliances between local communities and external institutions. The objective is to assist the design of resource management and conservation programs that enhance the capacity of coastal communities in Oceania to confront both diminishing marine resources and the effects of climate change by providing guidelines for protecting marine biodiversity and vulnerable ecosystem functions. This article describes a management framework that hybridizes local beliefs and institutions expressed in customary management (CM) with such modern management concepts as marine protected areas (MPAs) and ecosystem-based management (EBM). Hybrid management accommodates the social, political, economic, and cultural contexts of Oceanic communities and, compared with recent or conventional management approaches, can therefore better address fundamental local concerns such as coastal degradation, climate change, sea level rise, weak governance, corruption, limited resources and staff to manage and monitor marine resources, and increasing poverty. Research on the hybridization of management systems demonstrates opportunities to establish context-appropriate EBM and/or other managerial arrangements that include terrestrial and adjacent coastal-marine ecosystems. Formal and informal CM systems are widespread in Oceania and in some parts of Southeast Asia, and if appropriate strategies are employed rapid progress toward hybrid CM-EBM could be enabled.
- Full Text:
- Date Issued: 2013
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 and photodynamic potential of tetra-and octa-triethyleneoxysulfonyl substituted zinc phthalocyanines
- Atilla, Devrim, Savdan, Nil, Durmus, Mahmut, Gürek, Ayşe Gül, Khan, Tania, Rück, Angelika, Walt, Heinrich, Nyokong, Tebello, Ahsen, Vefa
- Authors: Atilla, Devrim , Savdan, Nil , Durmus, Mahmut , Gürek, Ayşe Gül , Khan, Tania , Rück, Angelika , Walt, Heinrich , Nyokong, Tebello , Ahsen, Vefa
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281342 , vital:55715 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.022"
- Description: Synthesis of the water soluble zinc phthalocyanines (3, 4) obtained from the phthalonitriles substituted with oligo(ethyleneoxy)thia groups are described. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, including HSQC, HMBC and COSY bidimensional correlation techniques, electronic spectroscopy and mass spectra. The aggregation behaviour of the phthalocyanine compounds (3, 4) was investigated using UV–vis spectroscopy in dimethylsulphoxide. Photochemical and photophysical measurements were conducted on oligo(ethyleneoxy)thia appended zinc phthalocyanines. General trends are described for quantum yields of photodegredation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The phototoxicity against cancer cells of the new compounds was investigated during several in vitro experiments. The dye-sensitized photooxidation of 1,3-diphenylisobenzofurane via 1O2 was studied in dimethylsulphoxide.
- Full Text:
- Date Issued: 2007
- Authors: Atilla, Devrim , Savdan, Nil , Durmus, Mahmut , Gürek, Ayşe Gül , Khan, Tania , Rück, Angelika , Walt, Heinrich , Nyokong, Tebello , Ahsen, Vefa
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281342 , vital:55715 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.022"
- Description: Synthesis of the water soluble zinc phthalocyanines (3, 4) obtained from the phthalonitriles substituted with oligo(ethyleneoxy)thia groups are described. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, including HSQC, HMBC and COSY bidimensional correlation techniques, electronic spectroscopy and mass spectra. The aggregation behaviour of the phthalocyanine compounds (3, 4) was investigated using UV–vis spectroscopy in dimethylsulphoxide. Photochemical and photophysical measurements were conducted on oligo(ethyleneoxy)thia appended zinc phthalocyanines. General trends are described for quantum yields of photodegredation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The phototoxicity against cancer cells of the new compounds was investigated during several in vitro experiments. The dye-sensitized photooxidation of 1,3-diphenylisobenzofurane via 1O2 was studied in dimethylsulphoxide.
- Full Text:
- Date Issued: 2007
Biosynthesis of silver nanoparticles from Acacia mearnsii De Wild stem bark and its antinociceptive properties
- Avoseh, Opeyemi N, Oyedeji, Opeoluwa O, Aremu, Olukayode, Nkeh-Chungag, Benedicta N, Songca, Sandile P, Oyedeji, Adebola Omowunmi, Mohan, Sneha, Oluwafemi, Oluwatobi S
- Authors: Avoseh, Opeyemi N , Oyedeji, Opeoluwa O , Aremu, Olukayode , Nkeh-Chungag, Benedicta N , Songca, Sandile P , Oyedeji, Adebola Omowunmi , Mohan, Sneha , Oluwafemi, Oluwatobi S
- Date: 2017
- Subjects: Metal nanoparticles , Acacia mearnsii , Nociceptive pain
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/1528 , vital:37774 , https://doi.org/10.1080/17518253.2017.1287310
- Description: The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%.
- Full Text:
- Date Issued: 2017
- Authors: Avoseh, Opeyemi N , Oyedeji, Opeoluwa O , Aremu, Olukayode , Nkeh-Chungag, Benedicta N , Songca, Sandile P , Oyedeji, Adebola Omowunmi , Mohan, Sneha , Oluwafemi, Oluwatobi S
- Date: 2017
- Subjects: Metal nanoparticles , Acacia mearnsii , Nociceptive pain
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/1528 , vital:37774 , https://doi.org/10.1080/17518253.2017.1287310
- Description: The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%.
- Full Text:
- Date Issued: 2017
Comprehensive data on the mechanical properties and biodegradation profile of polylactide composites developed for hard tissue repairs
- Aworinde, Abraham K, Adeosun, Samson O, Oyawale, Festus A, Emagbetere, Eyere, Ishola, Felix A, Olatunji, Obafemi, Akinlab, Stephen, Oyedepo, Sunday O, Ajayi, Oluseyi O, Akinlabi, Esther T
- Authors: Aworinde, Abraham K , Adeosun, Samson O , Oyawale, Festus A , Emagbetere, Eyere , Ishola, Felix A , Olatunji, Obafemi , Akinlab, Stephen , Oyedepo, Sunday O , Ajayi, Oluseyi O , Akinlabi, Esther T
- Date: 2020
- Subjects: Regeneration (Biology) , Vickers microhardness , Melt-blending technique
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3149 , vital:43158 , https://doi.org/10.1016/j.dib.2020.106107
- Description: Africa, the ancestral home of all modern humans, is the most informative continent for understanding the human genome and its contribution to complex disease. To better understand the genetics of schizophrenia, we studied the illness in the Xhosa population of South Africa, recruiting 909 cases and 917 age-, gender-, and residence-matched controls. Individuals with schizophrenia were significantly more likely than controls to harbor private, severely damaging mutations in genes that are critical to synaptic function, including neural circuitry mediated by the neurotransmitters glutamine, γ-aminobutyric acid, and dopamine. Schizophrenia is genetically highly heterogeneous, involving severe ultrarare mutations in genes that are critical to synaptic plasticity. The depth of genetic variation in Africa revealed this relationship with a moderate sample size and informed our understanding of the genetics of schizophrenia worldwide.
- Full Text:
- Date Issued: 2020
- Authors: Aworinde, Abraham K , Adeosun, Samson O , Oyawale, Festus A , Emagbetere, Eyere , Ishola, Felix A , Olatunji, Obafemi , Akinlab, Stephen , Oyedepo, Sunday O , Ajayi, Oluseyi O , Akinlabi, Esther T
- Date: 2020
- Subjects: Regeneration (Biology) , Vickers microhardness , Melt-blending technique
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3149 , vital:43158 , https://doi.org/10.1016/j.dib.2020.106107
- Description: Africa, the ancestral home of all modern humans, is the most informative continent for understanding the human genome and its contribution to complex disease. To better understand the genetics of schizophrenia, we studied the illness in the Xhosa population of South Africa, recruiting 909 cases and 917 age-, gender-, and residence-matched controls. Individuals with schizophrenia were significantly more likely than controls to harbor private, severely damaging mutations in genes that are critical to synaptic function, including neural circuitry mediated by the neurotransmitters glutamine, γ-aminobutyric acid, and dopamine. Schizophrenia is genetically highly heterogeneous, involving severe ultrarare mutations in genes that are critical to synaptic plasticity. The depth of genetic variation in Africa revealed this relationship with a moderate sample size and informed our understanding of the genetics of schizophrenia worldwide.
- Full Text:
- Date Issued: 2020
Thien-2-yl substituted chlorins as photosensitizers for photodynamic therapy and photodynamic antimicrobial chemotherapy
- Babu, Balaji, Sindelo, Azole, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Sindelo, Azole , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190578 , vital:45007 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108886"
- Description: The synthesis and characterization of meso-tetra(thien-2-yl)chlorin (1) and meso-tetra(5-bromothien-2-yl)chlorin (2) is reported. These dyes have red-shifted absorption maxima compared to those of the analogous meso-tetraphenylchlorin (3). 1 and 2 have Q bands at 660 and 664 nm, respectively, singlet oxygen quantum yields of 0.60 and 0.64 and exhibit good photostability. The triplet states were found to have lifetimes of 8.6 μs in N2 purged DMF. Time-dependent cellular uptake of chlorins reached a maximum in MCF-7 cancer cells after 12 h. Upon irradiation with a Thorlabs M660L3 LED (280 mW cm−2), 2 exhibited better photocytotoxicity with an IC50 value of 2.7 μM against MCF-7 cells. The 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFDA) assay provided evidence for intracellular generation of reactive oxygen species. Photodynamic inactivation of bacteria by the chlorins was also studied. 2 exhibits better activity with log reduction values of 7.42 and 8.34 towards Staphylococcus aureus and Escherichia coli, respectively, under illumination for 60 min at 660 nm with a Thorlabs M660L3 LED (280 mW cm−2). These results demonstrate that 2 is a promising candidate for future in vivo experiments and merits further in-depth investigation.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Sindelo, Azole , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190578 , vital:45007 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108886"
- Description: The synthesis and characterization of meso-tetra(thien-2-yl)chlorin (1) and meso-tetra(5-bromothien-2-yl)chlorin (2) is reported. These dyes have red-shifted absorption maxima compared to those of the analogous meso-tetraphenylchlorin (3). 1 and 2 have Q bands at 660 and 664 nm, respectively, singlet oxygen quantum yields of 0.60 and 0.64 and exhibit good photostability. The triplet states were found to have lifetimes of 8.6 μs in N2 purged DMF. Time-dependent cellular uptake of chlorins reached a maximum in MCF-7 cancer cells after 12 h. Upon irradiation with a Thorlabs M660L3 LED (280 mW cm−2), 2 exhibited better photocytotoxicity with an IC50 value of 2.7 μM against MCF-7 cells. The 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFDA) assay provided evidence for intracellular generation of reactive oxygen species. Photodynamic inactivation of bacteria by the chlorins was also studied. 2 exhibits better activity with log reduction values of 7.42 and 8.34 towards Staphylococcus aureus and Escherichia coli, respectively, under illumination for 60 min at 660 nm with a Thorlabs M660L3 LED (280 mW cm−2). These results demonstrate that 2 is a promising candidate for future in vivo experiments and merits further in-depth investigation.
- Full Text:
- Date Issued: 2021
Photodynamic activity of Sn (IV) tetrathien-2-ylchlorin against MCF-7 breast cancer cells
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185920 , vital:44448 , xlink:href="https://doi.org/10.1039/d0dt03958f"
- Description: A new readily-synthesized Sn(IV) tetraarylchlorin with thien-2-yl substituents (SnC) has been prepared and fully characterized by various spectroscopic techniques and its photophysical and photochemical properties, such as the singlet oxygen quantum yield (ΦΔ), fluorescence quantum yield (ΦF), triplet lifetime (τT) and photostability, have been evaluated. SnC has an unusually high ΦΔ value of 0.89 in DMF. Studies on the photodynamic activity against MCF-7 breast cancer cells exhibited a very low IC50 value of 0.9 μM and high phototoxicity (dark versus light) indices of >27.8 after irradiation with a 660 nm Thorlabs LED (280 mW cm−2). The results demonstrate that Sn(IV) tetraarylchlorins of this type are suitable candidates for further in-depth PDT studies.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185920 , vital:44448 , xlink:href="https://doi.org/10.1039/d0dt03958f"
- Description: A new readily-synthesized Sn(IV) tetraarylchlorin with thien-2-yl substituents (SnC) has been prepared and fully characterized by various spectroscopic techniques and its photophysical and photochemical properties, such as the singlet oxygen quantum yield (ΦΔ), fluorescence quantum yield (ΦF), triplet lifetime (τT) and photostability, have been evaluated. SnC has an unusually high ΦΔ value of 0.89 in DMF. Studies on the photodynamic activity against MCF-7 breast cancer cells exhibited a very low IC50 value of 0.9 μM and high phototoxicity (dark versus light) indices of >27.8 after irradiation with a 660 nm Thorlabs LED (280 mW cm−2). The results demonstrate that Sn(IV) tetraarylchlorins of this type are suitable candidates for further in-depth PDT studies.
- Full Text:
- Date Issued: 2021
Naked Eye and Colorimetric Detection of Cyanide with a 1, 3‐Diethyl‐2‐thiobarbituric Acid Substituted Ferrocene Chemosensor
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190567 , vital:45006 , xlink:href="https://doi.org/10.1002/slct.202100163"
- Description: A 1,3-diethyl-2-thiobarbituric-acid-substituted ferrocene (FET) has been evaluated for its cyanide sensing ability by UV-visible absorption spectroscopy and other characterization methods. FET provides a ratiometric colorimetric chemosensor for the CN− anion detection in 1 : 1 DMSO/H2O (v/v) solution. The addition of CN− results in an immediate color change from dark blue to pale orange that is visible to the naked eye. Mechanism studies and molecular modelling with TD-DFT calculations demonstrate that nucleophilic addition of CN− to an electrophilic sp2-hybridized carbon atom blocks charge transfer from the ferrocene ring complex to the thiobarbituric acid moiety. The FET sensor exhibits excellent selectivity for CN− and a limit of detection of 0.2 μM.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190567 , vital:45006 , xlink:href="https://doi.org/10.1002/slct.202100163"
- Description: A 1,3-diethyl-2-thiobarbituric-acid-substituted ferrocene (FET) has been evaluated for its cyanide sensing ability by UV-visible absorption spectroscopy and other characterization methods. FET provides a ratiometric colorimetric chemosensor for the CN− anion detection in 1 : 1 DMSO/H2O (v/v) solution. The addition of CN− results in an immediate color change from dark blue to pale orange that is visible to the naked eye. Mechanism studies and molecular modelling with TD-DFT calculations demonstrate that nucleophilic addition of CN− to an electrophilic sp2-hybridized carbon atom blocks charge transfer from the ferrocene ring complex to the thiobarbituric acid moiety. The FET sensor exhibits excellent selectivity for CN− and a limit of detection of 0.2 μM.
- Full Text:
- Date Issued: 2021
Photocytotoxicity of heavy-atom-free thiobarbituric acid functionalized pyrene derivatives against MCF-7 cancer cells
- Babu, Balaji, Ali, Thaslima A, Ochappan, Thivagar, Mack, John, Nyokong, Tebello, Sethuraman, Mathur G
- Authors: Babu, Balaji , Ali, Thaslima A , Ochappan, Thivagar , Mack, John , Nyokong, Tebello , Sethuraman, Mathur G
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190556 , vital:45005 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.102102"
- Description: Two thiobarbituric acid-functionalized pyrene derivatives (P1, P2) have been synthesized to explore the photophysical properties and photodynamic activity of dyes of this type. Both compounds exhibit an intense intramolecular charge transfer (ICT) band at ca. 470 nm, which is absent in the spectra of the precursor. P1 and P2 exhibit singlet oxygen generation on irradiation with light with moderate singlet oxygen yields of 0.36 and 0.32, respectively, in DMSO. P1 showed better photodynamic activity against MCF-7 cells with an IC50 value of 18.3 μM under illumination at 455 nm for 60 min with a Thorlabs M455L3 LED (330 mW.cm−2).
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Ali, Thaslima A , Ochappan, Thivagar , Mack, John , Nyokong, Tebello , Sethuraman, Mathur G
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190556 , vital:45005 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.102102"
- Description: Two thiobarbituric acid-functionalized pyrene derivatives (P1, P2) have been synthesized to explore the photophysical properties and photodynamic activity of dyes of this type. Both compounds exhibit an intense intramolecular charge transfer (ICT) band at ca. 470 nm, which is absent in the spectra of the precursor. P1 and P2 exhibit singlet oxygen generation on irradiation with light with moderate singlet oxygen yields of 0.36 and 0.32, respectively, in DMSO. P1 showed better photodynamic activity against MCF-7 cells with an IC50 value of 18.3 μM under illumination at 455 nm for 60 min with a Thorlabs M455L3 LED (330 mW.cm−2).
- Full Text:
- Date Issued: 2021
A heavy-atom-free π-extended N-confused porphyrin as a photosensitizer for photodynamic therapy
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
- Full Text:
- Date Issued: 2021
A Sn (iv) porphyrin with mitochondria targeting properties for enhanced photodynamic activity against MCF-7 cells
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
An octabrominated Sn (iv) tetraisopropylporphyrin as a photosensitizer dye for singlet oxygen biomedical applications
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186679 , vital:44524 , xlink:href="https://doi.org/10.1039/D0DT01915A"
- Description: Two novel Sn(IV) tetraisopropylphenylporphyrins have been synthesized to explore the effect of octabromination at the β-pyrrole positions on their photophysical properties and photodynamic activity. The lower energy Q band of an octabrominated complex lies at 675 nm well within the therapeutic window. The octabrominated dye has a relatively high singlet oxygen quantum yield of 0.78 in DMF and exhibits favorable photodynamic activity against MCF-7 cells with an IC50 value of 10.7 μM and a 5.74 log reduction value (5 μM) towards S. aureus under illumination at 660 nm for 60 min with a Thorlabs M660L3 LED (280 mW cm−2).
- Full Text:
- Date Issued: 2020
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186679 , vital:44524 , xlink:href="https://doi.org/10.1039/D0DT01915A"
- Description: Two novel Sn(IV) tetraisopropylphenylporphyrins have been synthesized to explore the effect of octabromination at the β-pyrrole positions on their photophysical properties and photodynamic activity. The lower energy Q band of an octabrominated complex lies at 675 nm well within the therapeutic window. The octabrominated dye has a relatively high singlet oxygen quantum yield of 0.78 in DMF and exhibits favorable photodynamic activity against MCF-7 cells with an IC50 value of 10.7 μM and a 5.74 log reduction value (5 μM) towards S. aureus under illumination at 660 nm for 60 min with a Thorlabs M660L3 LED (280 mW cm−2).
- Full Text:
- Date Issued: 2020
Sn (iv) N-confused porphyrins as photosensitizer dyes for photodynamic therapy in the near IR region
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186648 , vital:44521 , xlink:href="https://doi.org/10.1039/D0DT03296D"
- Description: The utility of Sn(IV) N-confused porphyrin (SnNCP) for use as photosensitizer dyes in photodynamic therapy is investigated. SnNCP has an unusually high singlet oxygen quantum yield of 0.72 in DMSO. IC50 values of 1.6 and 12.8 μM were obtained against MCF-7 cells upon irradiation with 660 and 780 nm LEDs.
- Full Text:
- Date Issued: 2020
Sn (iv) N-confused porphyrins as photosensitizer dyes for photodynamic therapy in the near IR region
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186648 , vital:44521 , xlink:href="https://doi.org/10.1039/D0DT03296D"
- Description: The utility of Sn(IV) N-confused porphyrin (SnNCP) for use as photosensitizer dyes in photodynamic therapy is investigated. SnNCP has an unusually high singlet oxygen quantum yield of 0.72 in DMSO. IC50 values of 1.6 and 12.8 μM were obtained against MCF-7 cells upon irradiation with 660 and 780 nm LEDs.
- Full Text:
- Date Issued: 2020
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
Synthesis, characterization and photodynamic activity of Sn (iv) triarylcorroles with red-shifted Q bands
- Babu, Balaji, Prinsloo, Earl, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187521 , vital:44668 , xlink:href="https://doi.org/10.1039/C9NJ03391B"
- Description: Two Sn(IV) triarylcorroles were synthesised and characterized. The absorption spectrum of a meso-thien-2-yl substituted tin(IV)corrole (1-Sn) is red shifted compared to its phenyl analogue (2-Sn) and shows no sign of aggregation in solution. 1-Sn and 2-Sn exhibited singlet oxygen quantum yields of 0.87 and 0.54 in DMF, and have a triplet lifetime of 31 and 50 μs, respectively. Time dependent cellular uptake in MCF-7 cells for 1-Sn reached a peak at 24 h, and 1-Sn was found to be more lipophilic than 2-Sn. 1-Sn showed good photo-cytotoxicity on exposure to a Thorlabs 625 nm LED with an IC50 value of 3.2 μM and remained inactive in the dark.
- Full Text:
- Date Issued: 2019
- Authors: Babu, Balaji , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187521 , vital:44668 , xlink:href="https://doi.org/10.1039/C9NJ03391B"
- Description: Two Sn(IV) triarylcorroles were synthesised and characterized. The absorption spectrum of a meso-thien-2-yl substituted tin(IV)corrole (1-Sn) is red shifted compared to its phenyl analogue (2-Sn) and shows no sign of aggregation in solution. 1-Sn and 2-Sn exhibited singlet oxygen quantum yields of 0.87 and 0.54 in DMF, and have a triplet lifetime of 31 and 50 μs, respectively. Time dependent cellular uptake in MCF-7 cells for 1-Sn reached a peak at 24 h, and 1-Sn was found to be more lipophilic than 2-Sn. 1-Sn showed good photo-cytotoxicity on exposure to a Thorlabs 625 nm LED with an IC50 value of 3.2 μM and remained inactive in the dark.
- Full Text:
- Date Issued: 2019
Valuing South Africa's savannas: Methodological Issues
- Ballance, A, Shackleton, Charlie M, Shackleton, Sheona E, Geach, B S, Crookes, D, De Wit, M, Evans, J, von Maltitz, G, Willis, C B, Kelatwang, S, Havemann, J
- Authors: Ballance, A , Shackleton, Charlie M , Shackleton, Sheona E , Geach, B S , Crookes, D , De Wit, M , Evans, J , von Maltitz, G , Willis, C B , Kelatwang, S , Havemann, J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182262 , vital:43816 , xlink:href="https://hdl.handle.net/10520/EJC33860"
- Description: Natural resource valuation techniques have been applied in recent years to savannas and savanna resources in South and southern Africa. Results from these studies have been used to demonstrate the importance of savannas, and to assist in resource-use planning. Because these studies have been conducted to meet different research objectives a large number of disparities exist between studies. This makes comparison of results difficult and identification of underlying drivers of value is problematic. This paper discusses issues which can lead to differences in estimates of resource value, and makes recommendations for future studies to reduce incompatibilities. In particular, this paper recommends that future studies make full descriptions of the objectives of the study, the background characteristics of the study area (including the social, political, economic, cultural, and biophysical characteristics), the methods used, and assumptions made. In this way, the values reported from case studies may be used in other research and decision-making exercises.
- Full Text:
- Date Issued: 2001
- Authors: Ballance, A , Shackleton, Charlie M , Shackleton, Sheona E , Geach, B S , Crookes, D , De Wit, M , Evans, J , von Maltitz, G , Willis, C B , Kelatwang, S , Havemann, J
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182262 , vital:43816 , xlink:href="https://hdl.handle.net/10520/EJC33860"
- Description: Natural resource valuation techniques have been applied in recent years to savannas and savanna resources in South and southern Africa. Results from these studies have been used to demonstrate the importance of savannas, and to assist in resource-use planning. Because these studies have been conducted to meet different research objectives a large number of disparities exist between studies. This makes comparison of results difficult and identification of underlying drivers of value is problematic. This paper discusses issues which can lead to differences in estimates of resource value, and makes recommendations for future studies to reduce incompatibilities. In particular, this paper recommends that future studies make full descriptions of the objectives of the study, the background characteristics of the study area (including the social, political, economic, cultural, and biophysical characteristics), the methods used, and assumptions made. In this way, the values reported from case studies may be used in other research and decision-making exercises.
- Full Text:
- Date Issued: 2001
The association between HIV tri-therapy with the development of Type-2 Diabetes Mellitus in a rural South African district: A case-control study
- Bam, Nokwanda E, Mabunda, Sikhumbuzo A, Ntsaba, Jafta, Apalata, Teke, Monatshila, Sibusisu C, Chitha, Wesile
- Authors: Bam, Nokwanda E , Mabunda, Sikhumbuzo A , Ntsaba, Jafta , Apalata, Teke , Monatshila, Sibusisu C , Chitha, Wesile
- Date: 2020
- Subjects: Type 2 diabetes , AIDS (Disease) , Rural health
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4008 , vital:43983 , https://doi.org/10.1371/journal.pone.0244067
- Description: Combination antiretroviral drugs(cARVs)prolong patients’ lives but are unfortunately thought to increase complications related to metabolic disorders including type-2 Diabetes Mellitus(DM).We sought to confirm the association of cARVs with type-2DM and ascertain the extent of this association in a rural South African setting. A case-control study of 177 (33.33%) cases with HIV/AIDS and type-2 DM were selected and compared with 354 (66.67%) non-DM HIV/AIDS unmatched controls from a rural district of South Africa’s third most populous province (Eastern Cape). Cases were identified from community health centres using the district health information system, and controls were identified using simple random sampling from the same health facilities. Odds Ratios (OR), together with 95% confidence intervals, were calculated for all the univariable and multivariable logistic analyses. This study found that cARVs significantly increased the occurrence of type-2 DM among HIV patients. Patients on protease inhibitors (PIs) were at least 21 times significantly more likely to be diabetic than those on the fixed dose combination (FDC); those on stavudine (D4T) and zidovudine (AZT) were 2.45 times and 9.44 times respectively more likely to be diabetic than those on FDC. The odds of diabetes increased by more than three-folds for those who had been on antiretroviral drugs for more than 6 years.
- Full Text:
- Date Issued: 2020
- Authors: Bam, Nokwanda E , Mabunda, Sikhumbuzo A , Ntsaba, Jafta , Apalata, Teke , Monatshila, Sibusisu C , Chitha, Wesile
- Date: 2020
- Subjects: Type 2 diabetes , AIDS (Disease) , Rural health
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4008 , vital:43983 , https://doi.org/10.1371/journal.pone.0244067
- Description: Combination antiretroviral drugs(cARVs)prolong patients’ lives but are unfortunately thought to increase complications related to metabolic disorders including type-2 Diabetes Mellitus(DM).We sought to confirm the association of cARVs with type-2DM and ascertain the extent of this association in a rural South African setting. A case-control study of 177 (33.33%) cases with HIV/AIDS and type-2 DM were selected and compared with 354 (66.67%) non-DM HIV/AIDS unmatched controls from a rural district of South Africa’s third most populous province (Eastern Cape). Cases were identified from community health centres using the district health information system, and controls were identified using simple random sampling from the same health facilities. Odds Ratios (OR), together with 95% confidence intervals, were calculated for all the univariable and multivariable logistic analyses. This study found that cARVs significantly increased the occurrence of type-2 DM among HIV patients. Patients on protease inhibitors (PIs) were at least 21 times significantly more likely to be diabetic than those on the fixed dose combination (FDC); those on stavudine (D4T) and zidovudine (AZT) were 2.45 times and 9.44 times respectively more likely to be diabetic than those on FDC. The odds of diabetes increased by more than three-folds for those who had been on antiretroviral drugs for more than 6 years.
- Full Text:
- Date Issued: 2020