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:
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:
Substituent effect on the photophysical and nonlinear optical characteristics of Si phthalocyanine–Detonated nanodiamond conjugated systems in solution
- Matshitse, Refilwe, Nyokong, Tebello
- Authors: Matshitse, Refilwe , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186293 , vital:44482 , xlink:href="https://doi.org/10.1016/j.ica.2020.119447"
- Description: This work reports on the photophysical, nonlinear absorption and optical limiting properties of detonation nanodiamonds (DNDs)-silicon phthalocyanine nanoconjugate systems. Si(IV) hydroxide phthalocyanines employed are: 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyaninato (Si(OH)2TPPc), 2,9(10),16(17),23(24)-tetrakis-(4-tert-butyl) phthalocyanato (Si(OH)2TBPc) and phthalocyanato(Si(OH)2Pc). Pcs were covalently linked to nanondiamonds and investigated using 532 nm laser excitation at 7 ns pulses for their optical limiting properties. Si(OH)2TBPc and Si(OH)2Pc gave larger triplet quantum yields when linked to DNDs, while the value decreased for Si(OH)2TPPc in the presence of DNDs due to aggregation. However all Pcs showed enhanced nonlinear optical properties in the presence of DNDs. DNDs-Si(OH)2TPPc and DNDs-Si (OH)2TBPc gave the highest imaginary third-order susceptibility (Im[X(3)]) and hyperpolarizability (γ) at 5.19 × 10−8 and 3.85 × 10−8 esu and 2.66 × 10−27 and 1.97 × 10−27 esu, respectively. DNDs-Si(OH)2TBPc nanoconjugates showed lowest limiting threshold (Ilim) value of 0.01 J.cm−2 relative to 0.09 for DNDs-Si (OH)2TPPc.
- Full Text:
- Authors: Matshitse, Refilwe , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186293 , vital:44482 , xlink:href="https://doi.org/10.1016/j.ica.2020.119447"
- Description: This work reports on the photophysical, nonlinear absorption and optical limiting properties of detonation nanodiamonds (DNDs)-silicon phthalocyanine nanoconjugate systems. Si(IV) hydroxide phthalocyanines employed are: 2,9(10),16(17),23(24)-tetrakis-(4-pyridyloxy) phthalocyaninato (Si(OH)2TPPc), 2,9(10),16(17),23(24)-tetrakis-(4-tert-butyl) phthalocyanato (Si(OH)2TBPc) and phthalocyanato(Si(OH)2Pc). Pcs were covalently linked to nanondiamonds and investigated using 532 nm laser excitation at 7 ns pulses for their optical limiting properties. Si(OH)2TBPc and Si(OH)2Pc gave larger triplet quantum yields when linked to DNDs, while the value decreased for Si(OH)2TPPc in the presence of DNDs due to aggregation. However all Pcs showed enhanced nonlinear optical properties in the presence of DNDs. DNDs-Si(OH)2TPPc and DNDs-Si (OH)2TBPc gave the highest imaginary third-order susceptibility (Im[X(3)]) and hyperpolarizability (γ) at 5.19 × 10−8 and 3.85 × 10−8 esu and 2.66 × 10−27 and 1.97 × 10−27 esu, respectively. DNDs-Si(OH)2TBPc nanoconjugates showed lowest limiting threshold (Ilim) value of 0.01 J.cm−2 relative to 0.09 for DNDs-Si (OH)2TPPc.
- Full Text:
Susceptibility of Staphylococcus aureus to porphyrin-silver nanoparticle mediated photodynamic antimicrobial chemotherapy
- Shabangu, Samuel M, Babu, Balaji, Soy, Rodah C, Ovim, James, Amuhaya, Edith, Nyokong, Tebello
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Ovim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186262 , vital:44479 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117158"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is employed against multi drug resistant Staphylococcus aureus using porphyrins combined with silver nanoparticles to bring about a combined photodynamic effect. We employ Zn-meso-5,10,15,20-tetra(4-pyridyl) (1), Zn-meso-5,10,15,20-tetrathienyl (2), and Zn-meso-5-(4- hydroxyphenyl)- 10,15,20-tris(2-thienyl)(3) porphyrins and their self-assembled conjugates with silver nanoparticles for PACT against Staphylococcus aureus. Complex 3 with nanoparticles was found to perform better resulting in 0% bacterial viability at 60 min.
- Full Text:
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Ovim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186262 , vital:44479 , xlink:href="https://doi.org/10.1016/j.jlumin.2020.117158"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is employed against multi drug resistant Staphylococcus aureus using porphyrins combined with silver nanoparticles to bring about a combined photodynamic effect. We employ Zn-meso-5,10,15,20-tetra(4-pyridyl) (1), Zn-meso-5,10,15,20-tetrathienyl (2), and Zn-meso-5-(4- hydroxyphenyl)- 10,15,20-tris(2-thienyl)(3) porphyrins and their self-assembled conjugates with silver nanoparticles for PACT against Staphylococcus aureus. Complex 3 with nanoparticles was found to perform better resulting in 0% bacterial viability at 60 min.
- Full Text:
Synergistic effects of temperature and plant quality, on development time, size and lipid in Eccritotarsus eichhorniae
- Ismail, Mohannad, Brooks, Margot, Van Baaren, Joan, Albittar, Loulou
- Authors: Ismail, Mohannad , Brooks, Margot , Van Baaren, Joan , Albittar, Loulou
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426078 , vital:72312 , xlink:href="https://doi.org/10.1111/jen.12841"
- Description: Body size is an important biotic factor in evolutionary ecology, since it affects all aspects of insect physiology, life history and, consequently, fitness in ectothermic insects and how species adapt with their environment. It has been linked to tem-perature, with lower temperatures resulting in larger size. In this study, we tested the combined impact of temperature and plant quality on the body size, and de-velopment time from egg to adult of Eccritotarsus eichhorniae (Hemiptera: Miridae), an herbivorous insect used as a biological control agent against the invasive aquatic weed, water hyacinth Eichhornia crassipes (Pontederiaceae). We quantified insect size in individuals exposed to three temperatures (20, 25 and 30°C) combined with three qualities of host plant (high, medium and low) by calculating development time and measuring four traits: tibia length, forewing length, dry body mass and lipid con-tent, and we also determined the wing loading index. The development time, dry body mass and lipid content decreased linearly with increasing temperature and de-creasing plant quality. The decrease in size was the greatest when high temperature interacted with low plant quality. Smaller individuals had proportionately less lipid content. Wing loading decreased significantly with lower quality of host plant, result-ing in individuals likely to have theoretically higher flight ability. The results support the temperature-size rule (TSR) and that plant quality could influence the relationship between development time and the TSR. Results also provide novel evidence for a possible food quality-size rule for both sexes.
- Full Text:
- Authors: Ismail, Mohannad , Brooks, Margot , Van Baaren, Joan , Albittar, Loulou
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426078 , vital:72312 , xlink:href="https://doi.org/10.1111/jen.12841"
- Description: Body size is an important biotic factor in evolutionary ecology, since it affects all aspects of insect physiology, life history and, consequently, fitness in ectothermic insects and how species adapt with their environment. It has been linked to tem-perature, with lower temperatures resulting in larger size. In this study, we tested the combined impact of temperature and plant quality on the body size, and de-velopment time from egg to adult of Eccritotarsus eichhorniae (Hemiptera: Miridae), an herbivorous insect used as a biological control agent against the invasive aquatic weed, water hyacinth Eichhornia crassipes (Pontederiaceae). We quantified insect size in individuals exposed to three temperatures (20, 25 and 30°C) combined with three qualities of host plant (high, medium and low) by calculating development time and measuring four traits: tibia length, forewing length, dry body mass and lipid con-tent, and we also determined the wing loading index. The development time, dry body mass and lipid content decreased linearly with increasing temperature and de-creasing plant quality. The decrease in size was the greatest when high temperature interacted with low plant quality. Smaller individuals had proportionately less lipid content. Wing loading decreased significantly with lower quality of host plant, result-ing in individuals likely to have theoretically higher flight ability. The results support the temperature-size rule (TSR) and that plant quality could influence the relationship between development time and the TSR. Results also provide novel evidence for a possible food quality-size rule for both sexes.
- Full Text:
Synthesis and biological evaluation of bis-N2, N2′-(4-hydroxycoumarin-3-yl) ethylidene]-2, 3-dihydroxysuccinodihydrazides
- Manyeruke, Meloddy H, Tshiwawa, Thendamudzimu, Hoppe, Heinrich, Isaacs, Michelle, Seldon, Ronnett, Warner, Digby F, Krause, Rui W M, Kaye, Perry T
- Authors: Manyeruke, Meloddy H , Tshiwawa, Thendamudzimu , Hoppe, Heinrich , Isaacs, Michelle , Seldon, Ronnett , Warner, Digby F , Krause, Rui W M , Kaye, Perry T
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193430 , vital:45331 , xlink:href="https://doi.org/10.1016/j.bmcl.2019.126911"
- Description: A series of N2,N2′-bis[4-hydroxycoumarin-3-yl)ethylidene]-2,3-dihydroxysuccino-hydrazides, containing 4-hydroxycoumarin, hydrazine and tartaric acid moieties, have been prepared and examined for possible biological activity. Several of these compounds exhibit promising HIV-1 integrase inhibition (IC50 = 3.5 μM), and anti-T. brucei (32% viability) and anti-mycobacterial (Visual MIC90 = 15.63 μM) activity.
- Full Text:
- Authors: Manyeruke, Meloddy H , Tshiwawa, Thendamudzimu , Hoppe, Heinrich , Isaacs, Michelle , Seldon, Ronnett , Warner, Digby F , Krause, Rui W M , Kaye, Perry T
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193430 , vital:45331 , xlink:href="https://doi.org/10.1016/j.bmcl.2019.126911"
- Description: A series of N2,N2′-bis[4-hydroxycoumarin-3-yl)ethylidene]-2,3-dihydroxysuccino-hydrazides, containing 4-hydroxycoumarin, hydrazine and tartaric acid moieties, have been prepared and examined for possible biological activity. Several of these compounds exhibit promising HIV-1 integrase inhibition (IC50 = 3.5 μM), and anti-T. brucei (32% viability) and anti-mycobacterial (Visual MIC90 = 15.63 μM) activity.
- Full Text:
Synthesis and pharmacological evaluation of chlorin derivatives for photodynamic therapy of cholangiocarcinoma
- Gao, Ying-Hua, Li, Man-Yi, Saijad, Faiza, Wang, Jin-Hai, Meharban, Faiza, Gadoora, Malaz A, Yan, Yi-Jia, Nyokong, Tebello, Chen, Zhi-Long
- Authors: Gao, Ying-Hua , Li, Man-Yi , Saijad, Faiza , Wang, Jin-Hai , Meharban, Faiza , Gadoora, Malaz A , Yan, Yi-Jia , Nyokong, Tebello , Chen, Zhi-Long
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190873 , vital:45036 , xlink:href="https://doi.org/10.1016/j.ejmech.2020.112049"
- Description: Photodynamic therapy (PDT) has been developed as a promising therapeutic method in cancer treatment. The discovery of effective photosensitizer, which is the key factor of PDT, is highly desired. This paper reports the synthesis of novel chlorin derivatives, 5,10,15,20-tetraphenyl-[2:3]-[(methoxycarbonyl, carboxy)methano] chlorin I and 5,10,15,20-tetraphenyl-[2:3]- {[methoxycarbonyl, (2-hydroxyethyl)amide]methano}chlorin II. Their structures were characterized with UV–vis, 1HNMR, 13CNMR and HRMS spectroscopies. Photophysical and photochemical experiments results showed that compound I and II had an absorption maximum around 650 nm, with molar extinction coefficients of 1 × 104 M−1 cm−1. They had strong fluorescence emission in 650–660 nm upon excitation with 419–422 nm light. ESR showed that singlet oxygen was produced upon irradiation of compounds with 650 nm light in the presence of molecular oxygen. The photo-bleaching test indicated that the structure of compounds was stable. These new compounds exhibit excellent anti-tumor effects and lower toxicity compared to m-THPC in vitro and in vivo. Compound I and II had high tumor selectivity, which could induced tumor cells shrinkage and necrosis under 650 nm laser irradiation. Flow cytometry revealed that the compounds might mediate PDT effect at late apoptotic phase. These results make these compound I and II promising candidates for future study in photo-diagnosis and photodynamic therapy of cholangiocarcinoma.
- Full Text:
- Authors: Gao, Ying-Hua , Li, Man-Yi , Saijad, Faiza , Wang, Jin-Hai , Meharban, Faiza , Gadoora, Malaz A , Yan, Yi-Jia , Nyokong, Tebello , Chen, Zhi-Long
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190873 , vital:45036 , xlink:href="https://doi.org/10.1016/j.ejmech.2020.112049"
- Description: Photodynamic therapy (PDT) has been developed as a promising therapeutic method in cancer treatment. The discovery of effective photosensitizer, which is the key factor of PDT, is highly desired. This paper reports the synthesis of novel chlorin derivatives, 5,10,15,20-tetraphenyl-[2:3]-[(methoxycarbonyl, carboxy)methano] chlorin I and 5,10,15,20-tetraphenyl-[2:3]- {[methoxycarbonyl, (2-hydroxyethyl)amide]methano}chlorin II. Their structures were characterized with UV–vis, 1HNMR, 13CNMR and HRMS spectroscopies. Photophysical and photochemical experiments results showed that compound I and II had an absorption maximum around 650 nm, with molar extinction coefficients of 1 × 104 M−1 cm−1. They had strong fluorescence emission in 650–660 nm upon excitation with 419–422 nm light. ESR showed that singlet oxygen was produced upon irradiation of compounds with 650 nm light in the presence of molecular oxygen. The photo-bleaching test indicated that the structure of compounds was stable. These new compounds exhibit excellent anti-tumor effects and lower toxicity compared to m-THPC in vitro and in vivo. Compound I and II had high tumor selectivity, which could induced tumor cells shrinkage and necrosis under 650 nm laser irradiation. Flow cytometry revealed that the compounds might mediate PDT effect at late apoptotic phase. These results make these compound I and II promising candidates for future study in photo-diagnosis and photodynamic therapy of cholangiocarcinoma.
- Full Text:
Synthesis of novel Schiff base cobalt (II) and iron (iii) complexes as cathode catalysts for microbial fuel cell applications
- Sen, Pinar, Akagunduz, Dilan, Aghdam, Araz S, Cebeci, Fevzi C, Nyokong, Tebello, Catal, Tunc
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz S , Cebeci, Fevzi C , Nyokong, Tebello , Catal, Tunc
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190861 , vital:45035 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz S , Cebeci, Fevzi C , Nyokong, Tebello , Catal, Tunc
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190861 , vital:45035 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
Synthesis of novel Schiff base cobalt (II) and iron (iii) complexes as cathode catalysts for microbial fuel cell applications
- Sen, Pinar, Akagunduz, Dilan, Aghdam, Araz Sheibani, Cebeci, Fevzi C, Nyokong, Tebello
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz Sheibani , Cebeci, Fevzi C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187015 , vital:44556 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz Sheibani , Cebeci, Fevzi C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187015 , vital:44556 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
Temperature tolerance and humidity requirements of select entomopathogenic fungal isolates for future use in citrus IPM programmes
- Acheampong, M A, Coombes, Candice A, Moore, Sean D, Hill, Martin P
- Authors: Acheampong, M A , Coombes, Candice A , Moore, Sean D , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419399 , vital:71641 , xlink:href="https://doi.org/10.1016/j.jip.2020.107436"
- Description: Several isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitacae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitacae) have been investigated as possible microbial control agents of key citrus pests in South Africa. Although laboratory results have been promising, field trials against foliar pests have shown limited success. These findings highlighted the need to investigate other biological attributes of these fungal isolates besides virulence in order to select candidates that may be better suited for the foliar environment. Thus, this study investigated the influence of temperature on the in vitro growth of seven indigenous local isolates and the humidity requirements necessary to promote successful infection, in comparison with two commercial isolates (B. bassiana PPRI 5339 and M. anisopliae ICIPE 69). All the fungal isolates grew across a range of temperatures (8–34 °C) and optimally between 26 and 28 °C. Similarly, fungal infection of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) fifth instars occurred across a range of humidity levels (12%, 43%, 75%, 98%) regardless of fungal concentration, although external sporulation was restricted to treatments exposed to 98% relative humidity. It was concluded that neither temperature nor humidity, when considered alone, is likely to significantly influence the efficacy of any of the isolates in the field, given that they are active within temperature and humidity ranges experienced in South African citrus orchards.
- Full Text:
- Authors: Acheampong, M A , Coombes, Candice A , Moore, Sean D , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419399 , vital:71641 , xlink:href="https://doi.org/10.1016/j.jip.2020.107436"
- Description: Several isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitacae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitacae) have been investigated as possible microbial control agents of key citrus pests in South Africa. Although laboratory results have been promising, field trials against foliar pests have shown limited success. These findings highlighted the need to investigate other biological attributes of these fungal isolates besides virulence in order to select candidates that may be better suited for the foliar environment. Thus, this study investigated the influence of temperature on the in vitro growth of seven indigenous local isolates and the humidity requirements necessary to promote successful infection, in comparison with two commercial isolates (B. bassiana PPRI 5339 and M. anisopliae ICIPE 69). All the fungal isolates grew across a range of temperatures (8–34 °C) and optimally between 26 and 28 °C. Similarly, fungal infection of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) fifth instars occurred across a range of humidity levels (12%, 43%, 75%, 98%) regardless of fungal concentration, although external sporulation was restricted to treatments exposed to 98% relative humidity. It was concluded that neither temperature nor humidity, when considered alone, is likely to significantly influence the efficacy of any of the isolates in the field, given that they are active within temperature and humidity ranges experienced in South African citrus orchards.
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The crystal structure of 2-oxo-2H-chromen-4-yl acetate, C11H8O4
- Hulushe, Siya T, Manyeruke, Meloddy H, Hosten, Eric C, Kaye, Perry, Watkins, Gareth M
- Authors: Hulushe, Siya T , Manyeruke, Meloddy H , Hosten, Eric C , Kaye, Perry , Watkins, Gareth M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194048 , vital:45418 , xlink:href="https://doi.org/10.1515/ncrs-2019-0698"
- Description: C11H8O4, monoclinic, P21/c (no. 14), a = 4.5947(2) Å, b = 10.5414(3) Å, c = 19.1611(7) Å, β = 94.084(2)°, V = 925.70(6) Å3, Z = 4, Rgt(F) = 0.0376, wRref(F 2) = 0.1109,T = 200(2) K.CCDC no.: 1906383
- Full Text:
- Authors: Hulushe, Siya T , Manyeruke, Meloddy H , Hosten, Eric C , Kaye, Perry , Watkins, Gareth M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194048 , vital:45418 , xlink:href="https://doi.org/10.1515/ncrs-2019-0698"
- Description: C11H8O4, monoclinic, P21/c (no. 14), a = 4.5947(2) Å, b = 10.5414(3) Å, c = 19.1611(7) Å, β = 94.084(2)°, V = 925.70(6) Å3, Z = 4, Rgt(F) = 0.0376, wRref(F 2) = 0.1109,T = 200(2) K.CCDC no.: 1906383
- Full Text:
The effects of asymmetry in combination with reduced graphene oxide nanosheets on hydrazine electrocatalytic detection on cobalt phthalocyanines
- Mpeta, Lekhetho S, Sen, Pinar, Nyokong, Tebello
- Authors: Mpeta, Lekhetho S , Sen, Pinar , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186023 , vital:44456 , xlink:href="https://doi.org/10.1002/elan.202060094"
- Description: New symmetric {tetrakis [4-(4-(5-chloro-1Hbenzo[d]imidazol-2-yl) phenoxy phthalocyaninato] Co (II) (CoTPc)} and low symmetry {tris tert butyl phenoxy mono [4-(4-(5-chloro-1H-benzo[d]imidazol-2-yl) phenoxy phthalocyaninato]} Co (II) (CoMPc) were successfully synthesised and combined with reduced graphene oxide nanosheets (rGONS) for electrocatalytic detection of hydrazine. Prior to electrocatalysis, the probes were characterised using cyclic voltammetry and electrochemical impedance spectroscopy. Chronoamperometry was used to determine catalytic rate constant and the limit of detection (LOD). CoMPc-rGONS gave catalytic rate constant and LOD of 1.37×106 M 1 s 1 and 0.82 μM respectively, rendering it a more suitable probe for hydrazine, due to low symmetry.
- Full Text:
- Authors: Mpeta, Lekhetho S , Sen, Pinar , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186023 , vital:44456 , xlink:href="https://doi.org/10.1002/elan.202060094"
- Description: New symmetric {tetrakis [4-(4-(5-chloro-1Hbenzo[d]imidazol-2-yl) phenoxy phthalocyaninato] Co (II) (CoTPc)} and low symmetry {tris tert butyl phenoxy mono [4-(4-(5-chloro-1H-benzo[d]imidazol-2-yl) phenoxy phthalocyaninato]} Co (II) (CoMPc) were successfully synthesised and combined with reduced graphene oxide nanosheets (rGONS) for electrocatalytic detection of hydrazine. Prior to electrocatalysis, the probes were characterised using cyclic voltammetry and electrochemical impedance spectroscopy. Chronoamperometry was used to determine catalytic rate constant and the limit of detection (LOD). CoMPc-rGONS gave catalytic rate constant and LOD of 1.37×106 M 1 s 1 and 0.82 μM respectively, rendering it a more suitable probe for hydrazine, due to low symmetry.
- Full Text:
The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate creams
- Fauzee, Ayesha F B, Walker, Roderick B
- Authors: Fauzee, Ayesha F B , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183275 , vital:43937 , xlink:href="https://doi.org/10.1080/23311916.2020.1804713"
- Description: The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate (CP) cream formulations was investigated using a Central Composite Design of Experiments. Thirty batches of cream were manufactured and the formulation variables assessed were % v/v propylene glycol, % w/w Gelot® 64, cetostearyl alcohol and glyceryl monostearate content. The responses monitored included viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released at 72 hours. The responses were compared to those of a reference product, Dermovate® cream. ANOVA analysis revealed that viscosity, spreadability, and % CP released at 72 hours were significant formulation responses (p more than 0.05). Cetostearyl alcohol had the greatest impact on quality of pilot scale products. An increase in cetostearyl alcohol resulted in an increase in viscosity, a decrease in spreadability, and a decrease in % CP released at 72 hours. The optimized pilot scale CP formulation contained 46% v/v propylene glycol, 8.6% w/w cetostearyl alcohol, 10.5% w/w glyceryl monostearate, and 3.8% w/w Gelot® 64. The resultant viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released were 44633cP, 24.91cm2, 101.23 %, 76.98 g/cm2, 198.23 µS/cm, and 50.23%. The addition of cetostearyl alcohol and Gelot® 64 is critical for establishing a soft formulation that leads to the formation of a mixed crystal bilayer network of high viscosity. The formation of a separate crystalline lipophilic network usually occurs in semi-solid formulations that contain high concentrations of emulsifier, leading to an increase in shear stress and greater physicochemical stability of the formulation. The use of experimental design approaches to formulation development activities, permit evaluation of multiple factors simultaneously, reducing the time and costs associated with product development activities, whilst identifying a composition design space and ensuring stable and effective dosage forms are produced.
- Full Text:
- Authors: Fauzee, Ayesha F B , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183275 , vital:43937 , xlink:href="https://doi.org/10.1080/23311916.2020.1804713"
- Description: The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate (CP) cream formulations was investigated using a Central Composite Design of Experiments. Thirty batches of cream were manufactured and the formulation variables assessed were % v/v propylene glycol, % w/w Gelot® 64, cetostearyl alcohol and glyceryl monostearate content. The responses monitored included viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released at 72 hours. The responses were compared to those of a reference product, Dermovate® cream. ANOVA analysis revealed that viscosity, spreadability, and % CP released at 72 hours were significant formulation responses (p more than 0.05). Cetostearyl alcohol had the greatest impact on quality of pilot scale products. An increase in cetostearyl alcohol resulted in an increase in viscosity, a decrease in spreadability, and a decrease in % CP released at 72 hours. The optimized pilot scale CP formulation contained 46% v/v propylene glycol, 8.6% w/w cetostearyl alcohol, 10.5% w/w glyceryl monostearate, and 3.8% w/w Gelot® 64. The resultant viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released were 44633cP, 24.91cm2, 101.23 %, 76.98 g/cm2, 198.23 µS/cm, and 50.23%. The addition of cetostearyl alcohol and Gelot® 64 is critical for establishing a soft formulation that leads to the formation of a mixed crystal bilayer network of high viscosity. The formation of a separate crystalline lipophilic network usually occurs in semi-solid formulations that contain high concentrations of emulsifier, leading to an increase in shear stress and greater physicochemical stability of the formulation. The use of experimental design approaches to formulation development activities, permit evaluation of multiple factors simultaneously, reducing the time and costs associated with product development activities, whilst identifying a composition design space and ensuring stable and effective dosage forms are produced.
- Full Text:
The influence of citrus orchard age on the ecology of entomopathogenic fungi and nematodes
- Albertyn ,Sonnica, Moore, Sean D, Marsberg, Tamryn, Coombes, Candice A, Hill, Martin P
- Authors: Albertyn ,Sonnica , Moore, Sean D , Marsberg, Tamryn , Coombes, Candice A , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417545 , vital:71462 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
- Description: A three-year survey of the ecology of entomopathogenic nematodes (EPN) and entomopathogenic fungi (EPF) was undertaken on soils from citrus orchards of different ages to determine the influence of orchard age on the ecology of entomopathogenic fungi and nematodes. The influence of mulch and irrigation method on the occurrence of EPN and EPF was also determined. Most of the isolates recovered (n = 810) were Beauveria sp. (87.88% of all isolates), followed by Metarhizium sp. (11.87% of all isolates). Only 0.24% of soil samples collected during this study tested positive for EPN. All EPN isolates recovered were Heterorhabditis bacteriophora. No significant differences in EPF occurrence were recorded between orchards under drip and micro-sprinkler irrigation. EPF occurrence was significantly lower (P = 0.016) in orchards covered by mulch (31.85% ± 2.07% occurrence) than in orchards with no covering (38.57% ± 1.57% occurrence). EPF occurrence of 40.33 ± 2.13% was highest in non-bearing orchards, followed by mature orchards (nine years or older) (36.76 ± 2.05% of samples) with the lowest EPF occurrence of 25.30 ± 2.02% reported in juvenile orchards (four to eight years old). Juvenile orchards sustain significantly less EPF than mature and non-bearing orchards because of the combined negative impact of less favourable environmental conditions (lower shade density) and fungicide applications.
- Full Text:
- Authors: Albertyn ,Sonnica , Moore, Sean D , Marsberg, Tamryn , Coombes, Candice A , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417545 , vital:71462 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
- Description: A three-year survey of the ecology of entomopathogenic nematodes (EPN) and entomopathogenic fungi (EPF) was undertaken on soils from citrus orchards of different ages to determine the influence of orchard age on the ecology of entomopathogenic fungi and nematodes. The influence of mulch and irrigation method on the occurrence of EPN and EPF was also determined. Most of the isolates recovered (n = 810) were Beauveria sp. (87.88% of all isolates), followed by Metarhizium sp. (11.87% of all isolates). Only 0.24% of soil samples collected during this study tested positive for EPN. All EPN isolates recovered were Heterorhabditis bacteriophora. No significant differences in EPF occurrence were recorded between orchards under drip and micro-sprinkler irrigation. EPF occurrence was significantly lower (P = 0.016) in orchards covered by mulch (31.85% ± 2.07% occurrence) than in orchards with no covering (38.57% ± 1.57% occurrence). EPF occurrence of 40.33 ± 2.13% was highest in non-bearing orchards, followed by mature orchards (nine years or older) (36.76 ± 2.05% of samples) with the lowest EPF occurrence of 25.30 ± 2.02% reported in juvenile orchards (four to eight years old). Juvenile orchards sustain significantly less EPF than mature and non-bearing orchards because of the combined negative impact of less favourable environmental conditions (lower shade density) and fungicide applications.
- Full Text:
The invasive grass genus Nassella in South Africa: A synthesis
- Mapaura Anthony, Canavan, Kim N, Richardson, David M, Clark, Vincent R, Steenhuisen, Sandy-Lynn
- Authors: Mapaura Anthony , Canavan, Kim N , Richardson, David M , Clark, Vincent R , Steenhuisen, Sandy-Lynn
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424842 , vital:72188 , xlink:href="https://doi.org/10.1016/j.sajb.2020.08.031"
- Description: Three species of Nassella have naturalized in South Africa. Nassella trichotoma and N. tenuissima are declared weeds under category 1b of the National Environmental Management: Biodiversity Act (NEM:BA) and occur mainly in the montane grasslands of the Western and Eastern Cape provinces. Nassella neesiana is not listed in NEM:BA but is naturalized in the Eastern Cape, Western Cape and Free State provinces. Research conducted in the 1970s and 1980s led to vigorous government-funded awareness and control campaigns which ended in 2000. No research on Nassella distribution or control has been undertaken since then. Despite this hiatus, Nassella remains a dangerous genus in southern Africa, given the serious impacts of these species in similar social-ecological systems in Australia and New Zealand. This paper presents a synthesis of available information about Nassella invasions in South Africa and identifies research gaps. It specifically addresses these questions: What identification issues exist? What is the current spatial distribution of Nassella? What is the autecology of the genus? What are the social-ecological impacts of Nassella? What control measures are currently applied and what are their strengths and limitations? What do we know about Nassella distribution and its response to climate change? This paper highlights many knowledge gaps about Nassella, such as the species’ current distribution range, field identification and detection difficulties, and the uncoordinated control efforts that require urgent research to inform an effective management response.
- Full Text:
- Authors: Mapaura Anthony , Canavan, Kim N , Richardson, David M , Clark, Vincent R , Steenhuisen, Sandy-Lynn
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424842 , vital:72188 , xlink:href="https://doi.org/10.1016/j.sajb.2020.08.031"
- Description: Three species of Nassella have naturalized in South Africa. Nassella trichotoma and N. tenuissima are declared weeds under category 1b of the National Environmental Management: Biodiversity Act (NEM:BA) and occur mainly in the montane grasslands of the Western and Eastern Cape provinces. Nassella neesiana is not listed in NEM:BA but is naturalized in the Eastern Cape, Western Cape and Free State provinces. Research conducted in the 1970s and 1980s led to vigorous government-funded awareness and control campaigns which ended in 2000. No research on Nassella distribution or control has been undertaken since then. Despite this hiatus, Nassella remains a dangerous genus in southern Africa, given the serious impacts of these species in similar social-ecological systems in Australia and New Zealand. This paper presents a synthesis of available information about Nassella invasions in South Africa and identifies research gaps. It specifically addresses these questions: What identification issues exist? What is the current spatial distribution of Nassella? What is the autecology of the genus? What are the social-ecological impacts of Nassella? What control measures are currently applied and what are their strengths and limitations? What do we know about Nassella distribution and its response to climate change? This paper highlights many knowledge gaps about Nassella, such as the species’ current distribution range, field identification and detection difficulties, and the uncoordinated control efforts that require urgent research to inform an effective management response.
- Full Text:
The modulation of the photophysical and photodynamic therapy activities of a phthalocyanine by detonation nanodiamonds: Comparison with graphene quantum dots and carbon nanodots
- Matshitse, Refilwe, Managa, Muthumuni, Nyokong, Tebello
- Authors: Matshitse, Refilwe , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186690 , vital:44525 , xlink:href="https://doi.org/10.1016/j.diamond.2019.107617"
- Description: A positively charged phthalocyanine (2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ)) was non-covalently linked to carbon based nanoparticles: detonation nanodiamonds (DNDs), carbon dots (CDs) and graphene quantum dots (GQDs) to form nanosembles of DNDs-ZnTPPcQ, GQDs-ZnTPPcQ and CDs-ZnTPPcQ, respectively. Irrespective of its small size and the least number of Pcs (41.67 μg loading per milligram of DNDs), DNDs-ZnTPPcQ gave the highest singlet oxygen quantum yield (0.62) in dimethyl sulfoxide compared to the rest of the conjugates. This resulted in superior PDT activity against MCF7 breast cancer lines, with the lowest cell viability of 28% compared to ZnTPPcQ-CDs and ZnTPPcQ-GQDs at 30.1 ± 0.02% and 31.4 ± 0.23%, respectively.
- Full Text:
- Authors: Matshitse, Refilwe , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186690 , vital:44525 , xlink:href="https://doi.org/10.1016/j.diamond.2019.107617"
- Description: A positively charged phthalocyanine (2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ)) was non-covalently linked to carbon based nanoparticles: detonation nanodiamonds (DNDs), carbon dots (CDs) and graphene quantum dots (GQDs) to form nanosembles of DNDs-ZnTPPcQ, GQDs-ZnTPPcQ and CDs-ZnTPPcQ, respectively. Irrespective of its small size and the least number of Pcs (41.67 μg loading per milligram of DNDs), DNDs-ZnTPPcQ gave the highest singlet oxygen quantum yield (0.62) in dimethyl sulfoxide compared to the rest of the conjugates. This resulted in superior PDT activity against MCF7 breast cancer lines, with the lowest cell viability of 28% compared to ZnTPPcQ-CDs and ZnTPPcQ-GQDs at 30.1 ± 0.02% and 31.4 ± 0.23%, respectively.
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The photodynamic antimicrobial chemotherapy of Stapphylococcus aureus using an asymmetrical zinc phthalocyanine conjugated to silver and iron oxide based nanoparticles
- Mapukata, Sivuyisiwe, Nwahara, Nnamdi, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Nwahara, Nnamdi , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186078 , vital:44461 , xlink:href="https://doi.org/10.1016/j.jphotochem.2020.112813"
- Description: The synthesis and characterisation of asymmetrical zinc(II) 2(3)-mono-isophthalic acid-9(10),16(17),23 (24)-tri (tert-butylphenoxy) phthalocyanine (complex 4) are reported. The phthalocyanine is conjugated to cysteamine capped silver nanoparticles (Cys-Ag NPs), amine functionalised iron oxide magnetic nanoparticles (NH2-Fe3O4 NPs) and a core-shell composite of the two (Cys-Fe3O4@Ag) via amide bonds. The photo-physico-chemical properties of complex 4 and its respective nanoconjugates (4-Ag, 4-Fe3O4 NPs and 4-Fe3O4@Ag NPs) are also reported. The nanoconjugates showed improved triplet and singlet oxygen quantum yields compared to complex 4. The antibacterial activity of complex 4 and its nanoconjugates were also evaluated on S. aureus wherein their activity was found to be mainly visible light driven with the best catalyst being 4-Fe3O4@Ag. The work therefore demonstrates the feasibility of phthalocyanine-nanoparticle based compounds as potential agents in real life antibacterial treatment
- Full Text:
- Authors: Mapukata, Sivuyisiwe , Nwahara, Nnamdi , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186078 , vital:44461 , xlink:href="https://doi.org/10.1016/j.jphotochem.2020.112813"
- Description: The synthesis and characterisation of asymmetrical zinc(II) 2(3)-mono-isophthalic acid-9(10),16(17),23 (24)-tri (tert-butylphenoxy) phthalocyanine (complex 4) are reported. The phthalocyanine is conjugated to cysteamine capped silver nanoparticles (Cys-Ag NPs), amine functionalised iron oxide magnetic nanoparticles (NH2-Fe3O4 NPs) and a core-shell composite of the two (Cys-Fe3O4@Ag) via amide bonds. The photo-physico-chemical properties of complex 4 and its respective nanoconjugates (4-Ag, 4-Fe3O4 NPs and 4-Fe3O4@Ag NPs) are also reported. The nanoconjugates showed improved triplet and singlet oxygen quantum yields compared to complex 4. The antibacterial activity of complex 4 and its nanoconjugates were also evaluated on S. aureus wherein their activity was found to be mainly visible light driven with the best catalyst being 4-Fe3O4@Ag. The work therefore demonstrates the feasibility of phthalocyanine-nanoparticle based compounds as potential agents in real life antibacterial treatment
- Full Text:
The photophysicochemical properties and photodynamic therapy activity of In and Zn phthalocyanines when incorporated into individual or mixed Pluronic® micelles
- Motloung, Banele M, Babu, Balaji, Prinsloo, Earl, Nyokong, Tebello
- Authors: Motloung, Banele M , Babu, Balaji , Prinsloo, Earl , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186124 , vital:44465 , xlink:href="https://doi.org/10.1016/j.poly.2020.114683"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of tetra-pyridyloxy (1,2) and benzothiazole (3, 4) substituted indium (III) (1,3) and zinc (2, 4) phthalocyanines (Pcs) and their incorporation into Pluronic® F127 and Pluronic L121/F127 mixed micelles (the latter for 3 and 4 only) are presented in this study. The InPcs exhibited higher singlet oxygen (ΦΔ) at 0.76 and 0.68 compared to the ZnPc’s at 0.47 and 0.44 in dimethyl sulfoxide. The ΦΔ values in the presence of Pluronic® F127 and in water, were 0.39 and 0.42 for InPcs and 0.23 and 0.37 for ZnPc. The ΦΔ values in the presence of Pluronic F127/L121 mixed micelles for complex 3 and 4 were 0.51 and 0.29 in water. The Kp was determined using the water and octanol system. InPcs had larger Kp values suggesting that they are more likely to be taken up by the cancer cells hence they showed better PDT activity
- Full Text:
- Authors: Motloung, Banele M , Babu, Balaji , Prinsloo, Earl , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186124 , vital:44465 , xlink:href="https://doi.org/10.1016/j.poly.2020.114683"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of tetra-pyridyloxy (1,2) and benzothiazole (3, 4) substituted indium (III) (1,3) and zinc (2, 4) phthalocyanines (Pcs) and their incorporation into Pluronic® F127 and Pluronic L121/F127 mixed micelles (the latter for 3 and 4 only) are presented in this study. The InPcs exhibited higher singlet oxygen (ΦΔ) at 0.76 and 0.68 compared to the ZnPc’s at 0.47 and 0.44 in dimethyl sulfoxide. The ΦΔ values in the presence of Pluronic® F127 and in water, were 0.39 and 0.42 for InPcs and 0.23 and 0.37 for ZnPc. The ΦΔ values in the presence of Pluronic F127/L121 mixed micelles for complex 3 and 4 were 0.51 and 0.29 in water. The Kp was determined using the water and octanol system. InPcs had larger Kp values suggesting that they are more likely to be taken up by the cancer cells hence they showed better PDT activity
- Full Text:
The potential for biological control on cryptic plant invasions
- Canavan, Kim, Canavan, Susan, Harms, Nathan E, Lambertini, Carla, Paterson, Iain D, Thum, Ryan
- Authors: Canavan, Kim , Canavan, Susan , Harms, Nathan E , Lambertini, Carla , Paterson, Iain D , Thum, Ryan
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423562 , vital:72072 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104243"
- Description: Cryptic invasions can be defined as ‘the occurrence of an invasive species or genotype that was not previously recognised as alien in origin or not distinguished from other aliens’. Such invasions can result in negative impacts on the recipient ecosystems and disturb the evolutionary history of native plant populations. Many cryptic invasions have become so problematic that there is a need to implement control measures. This paper explores the potential for biological control to be implemented as a means of managing cryptic invasions. Firstly, the paper defines the different forms of cryptic invasion, differentiating between interspecific and intraspecific invasions; this hierarchy influences how to detect, study and ultimately implement biological control when cryptic invasions occur. Secondly, unique challenges associated with biological control programmes for cryptic invasions are addressed, including: the need for intraspecific level host specificity in agents, the occurrence of hybridisation between native species/lineages and the target weed, the role of enemy release in cryptic invasions in the presence of closely related native plant species/lineages, and a review of potential stakeholder conflicts of interest and legislation. Biological control of cryptic invasions has been shown to be possible, however the process will be more difficult and complex than controlling traditional targets and will likely take up more time and resources. If these challenges are overcome, then biological control programmes against cryptic invasions should be able to proceed and maintain the same standards as traditional biological control programmes.
- Full Text:
- Authors: Canavan, Kim , Canavan, Susan , Harms, Nathan E , Lambertini, Carla , Paterson, Iain D , Thum, Ryan
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423562 , vital:72072 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104243"
- Description: Cryptic invasions can be defined as ‘the occurrence of an invasive species or genotype that was not previously recognised as alien in origin or not distinguished from other aliens’. Such invasions can result in negative impacts on the recipient ecosystems and disturb the evolutionary history of native plant populations. Many cryptic invasions have become so problematic that there is a need to implement control measures. This paper explores the potential for biological control to be implemented as a means of managing cryptic invasions. Firstly, the paper defines the different forms of cryptic invasion, differentiating between interspecific and intraspecific invasions; this hierarchy influences how to detect, study and ultimately implement biological control when cryptic invasions occur. Secondly, unique challenges associated with biological control programmes for cryptic invasions are addressed, including: the need for intraspecific level host specificity in agents, the occurrence of hybridisation between native species/lineages and the target weed, the role of enemy release in cryptic invasions in the presence of closely related native plant species/lineages, and a review of potential stakeholder conflicts of interest and legislation. Biological control of cryptic invasions has been shown to be possible, however the process will be more difficult and complex than controlling traditional targets and will likely take up more time and resources. If these challenges are overcome, then biological control programmes against cryptic invasions should be able to proceed and maintain the same standards as traditional biological control programmes.
- Full Text:
The relationship between childhood trauma and schizophrenia in the Genomics of Schizophrenia in the Xhosa people (SAX) study in South Africa
- Mall, Sumaya, Platt, Jonathan M, Temmingh, Henk, Musenge, Eustasius, Campbell, Megan, Susser, Ezra, Stein, Dan J
- Authors: Mall, Sumaya , Platt, Jonathan M , Temmingh, Henk , Musenge, Eustasius , Campbell, Megan , Susser, Ezra , Stein, Dan J
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302567 , vital:58208 , xlink:href="https://doi.org/10.1017/S0033291719001703"
- Description: Background. Evidence from high-income countries suggests that childhood trauma is associated with schizophrenia. Studies of childhood trauma and schizophrenia in low and middle income (LMIC) countries are limited. This study examined the prevalence of childhood traumatic experiences among cases and controls and the relationship between specific and cumulative childhood traumatic experiences and schizophrenia in a sample in South Africa. Methods. Data were from the Genomics of Schizophrenia in the South African Xhosa people study. Cases with schizophrenia and matched controls were recruited from provincial hospitals and clinics in the Western and Eastern Cape regions in South Africa. Childhood traumatic experiences were measured using the Childhood Trauma Questionnaire (CTQ). Adjusted logistic regression models estimated associations between individual and cumulative childhood traumatic experiences and schizophrenia. Results. Traumatic experiences were more prevalent among cases than controls. The odds of schizophrenia were 2.44 times higher among those who experienced any trauma than those who reported no traumatic experiences (95% CI 1.77–3.37). The odds of schizophrenia were elevated among those who experienced physical/emotional abuse (OR 1.59, CI 1.28–1.97), neglect (OR 1.39, CI 1.16–1.68), and sexual abuse (OR 1.22, CI 1.03–1.45) compared to those who did not. Cumulative physical/emotional abuse and neglect experiences increased the odds of schizophrenia as a dose–response relationship. Conclusion. Childhood trauma is common in this population. Among many other benefits, interventions to prevent childhood trauma may contribute to a decreasing occurrence of schizophrenia.
- Full Text:
- Authors: Mall, Sumaya , Platt, Jonathan M , Temmingh, Henk , Musenge, Eustasius , Campbell, Megan , Susser, Ezra , Stein, Dan J
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302567 , vital:58208 , xlink:href="https://doi.org/10.1017/S0033291719001703"
- Description: Background. Evidence from high-income countries suggests that childhood trauma is associated with schizophrenia. Studies of childhood trauma and schizophrenia in low and middle income (LMIC) countries are limited. This study examined the prevalence of childhood traumatic experiences among cases and controls and the relationship between specific and cumulative childhood traumatic experiences and schizophrenia in a sample in South Africa. Methods. Data were from the Genomics of Schizophrenia in the South African Xhosa people study. Cases with schizophrenia and matched controls were recruited from provincial hospitals and clinics in the Western and Eastern Cape regions in South Africa. Childhood traumatic experiences were measured using the Childhood Trauma Questionnaire (CTQ). Adjusted logistic regression models estimated associations between individual and cumulative childhood traumatic experiences and schizophrenia. Results. Traumatic experiences were more prevalent among cases than controls. The odds of schizophrenia were 2.44 times higher among those who experienced any trauma than those who reported no traumatic experiences (95% CI 1.77–3.37). The odds of schizophrenia were elevated among those who experienced physical/emotional abuse (OR 1.59, CI 1.28–1.97), neglect (OR 1.39, CI 1.16–1.68), and sexual abuse (OR 1.22, CI 1.03–1.45) compared to those who did not. Cumulative physical/emotional abuse and neglect experiences increased the odds of schizophrenia as a dose–response relationship. Conclusion. Childhood trauma is common in this population. Among many other benefits, interventions to prevent childhood trauma may contribute to a decreasing occurrence of schizophrenia.
- Full Text:
The Rise of the Executive Dean and the Slide into Managerialism
- Authors: McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187139 , vital:44573 , xlink:href="http://dx.doi.org/10.17159/2221-4070/2020/v9i0a6"
- Description: Universities have long been characterised by hierarchical and paternalistic management structures and institutional cultures. Change is therefore to be welcomed but, in contexts where social change is urgently needed, it is possible to mistake a change in any direction as being worthwhile. Around the world, recent shifts in university leadership and management have been towards managerialist approaches that work against a shared responsibility for the academic project. Accusations of managerialism often refer to a general sense that institutions are becoming bureaucratic, or that it is the logic of the market that drives decision-making. But beyond vague complaints, these accusations fail to identify the exact processes whereby managerialism takes hold of the institution. This article hones in on one specific example of institutional change in order to argue that it is implicated in the move towards managerialism: most universities in South Africa have changed from having elected deans, selected by faculty, to executive deans, appointed by selection committee. Crudely distinguished, it can be said that elected deans represent the interests of their faculty up into various institutional structures whereas executive deans are tasked with implementing the decisions of top management down into faculty. This paper tracks the differences between the two forms of deanship through reflections on discussions about such a change at one South African institution, Rhodes University. It analyses the literature to argue that we do not have to choose between patriarchal management and compliance-based managerialism. Instead, we can choose shared responsibility for the academic project.
- Full Text:
- Authors: McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187139 , vital:44573 , xlink:href="http://dx.doi.org/10.17159/2221-4070/2020/v9i0a6"
- Description: Universities have long been characterised by hierarchical and paternalistic management structures and institutional cultures. Change is therefore to be welcomed but, in contexts where social change is urgently needed, it is possible to mistake a change in any direction as being worthwhile. Around the world, recent shifts in university leadership and management have been towards managerialist approaches that work against a shared responsibility for the academic project. Accusations of managerialism often refer to a general sense that institutions are becoming bureaucratic, or that it is the logic of the market that drives decision-making. But beyond vague complaints, these accusations fail to identify the exact processes whereby managerialism takes hold of the institution. This article hones in on one specific example of institutional change in order to argue that it is implicated in the move towards managerialism: most universities in South Africa have changed from having elected deans, selected by faculty, to executive deans, appointed by selection committee. Crudely distinguished, it can be said that elected deans represent the interests of their faculty up into various institutional structures whereas executive deans are tasked with implementing the decisions of top management down into faculty. This paper tracks the differences between the two forms of deanship through reflections on discussions about such a change at one South African institution, Rhodes University. It analyses the literature to argue that we do not have to choose between patriarchal management and compliance-based managerialism. Instead, we can choose shared responsibility for the academic project.
- Full Text: