Screening of ectomycorrhizal and other associated fungi in South African forest nurseries
- Chartier FitzGerald, Veronique C, Dames, Joanna F, Hawley, Greer L
- Authors: Chartier FitzGerald, Veronique C , Dames, Joanna F , Hawley, Greer L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426058 , vital:72310 , xlink:href="https://hdl.handle.net/10520/ejc-soufor-v82-n4-a8"
- Description: The South African forestry industry covers approximately 1.3 million hectares and is dependent on exotic pine and eucalypt species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi. This investigation assessed levels of naturally occurring ECM colonisation of Pinus patula seedlings from 10 different South African forestry nurseries using a grid line intersect method. Fungi from colonised roots were identified using morphological characteristics and Illumina sequencing. Colonisation of seedlings in production nurseries was low (2-21%). Morphologically, the ECM fungi Thelophora terrestris, Suillus sibiricus, and the genera Russula and Pseudotomentella were identified. Molecularly, the ECM fungi T. terrestris, Inocybe jacobi and the genus Sphaerosporella, as well as several other ECM-containing families were identified, along with many saprotrophic/ endophytic fungi belonging to genera such as Penicillium, Ramasonia and Talaromyces. As can be seen, a combination of both molecular and morphological identification techniques are needed as neither is able to give a full picture of the species present in isolation. This study reveals an initial insight into the root microbiome community associated with Pinus patula seedlings, which should be taken into account when inoculation with beneficial microbes is considered. It determined that natural ECM fungal root colonisation levels are very low throughout the South African nurseries investigated, indicating the need for ECM fungal inoculation, which can increase seedling growth, viability and resistance to pathogens.
- Full Text:
- Date Issued: 2020
- Authors: Chartier FitzGerald, Veronique C , Dames, Joanna F , Hawley, Greer L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426058 , vital:72310 , xlink:href="https://hdl.handle.net/10520/ejc-soufor-v82-n4-a8"
- Description: The South African forestry industry covers approximately 1.3 million hectares and is dependent on exotic pine and eucalypt species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi. This investigation assessed levels of naturally occurring ECM colonisation of Pinus patula seedlings from 10 different South African forestry nurseries using a grid line intersect method. Fungi from colonised roots were identified using morphological characteristics and Illumina sequencing. Colonisation of seedlings in production nurseries was low (2-21%). Morphologically, the ECM fungi Thelophora terrestris, Suillus sibiricus, and the genera Russula and Pseudotomentella were identified. Molecularly, the ECM fungi T. terrestris, Inocybe jacobi and the genus Sphaerosporella, as well as several other ECM-containing families were identified, along with many saprotrophic/ endophytic fungi belonging to genera such as Penicillium, Ramasonia and Talaromyces. As can be seen, a combination of both molecular and morphological identification techniques are needed as neither is able to give a full picture of the species present in isolation. This study reveals an initial insight into the root microbiome community associated with Pinus patula seedlings, which should be taken into account when inoculation with beneficial microbes is considered. It determined that natural ECM fungal root colonisation levels are very low throughout the South African nurseries investigated, indicating the need for ECM fungal inoculation, which can increase seedling growth, viability and resistance to pathogens.
- Full Text:
- Date Issued: 2020
Seeking Faculty Jobs Exploring the Relationship Between Academic’ s Social Class of Origin and Hiring Networks in Chilean Universities
- Authors: Chiappa, Roxana
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439508 , vital:73602 , https://doi.org/10.31619/caledu.n52.760
- Description: This research consisted of a qualitative case study on how a group of early-career doctorate holders in engineering (N=10) found academic positions in the Chilean academia. The analysis particularly explored how their social class of origin and their academic networks influenced their opportunities of getting an academic job. Findings show that social class of origin mediates the academic network configuration of academic-job seekers through unequal opportunities of completing their undergraduate degrees in prestigious Chilean universities with high research capacity, and subsequently, the unequal opportunities of studying a doctorate degree at top-ranked foreign universities. Only upper social class candidates who received their doctorate degrees from foreign highly prestigious universities were capable of securing positions at the top research-intensive Chilean universities. Overall, findings show that academic networks with professors who are knowledgeable of hiring processes are crucial at the moment of seeking academic jobs in the Chilean higher education system.
- Full Text:
- Date Issued: 2020
- Authors: Chiappa, Roxana
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439508 , vital:73602 , https://doi.org/10.31619/caledu.n52.760
- Description: This research consisted of a qualitative case study on how a group of early-career doctorate holders in engineering (N=10) found academic positions in the Chilean academia. The analysis particularly explored how their social class of origin and their academic networks influenced their opportunities of getting an academic job. Findings show that social class of origin mediates the academic network configuration of academic-job seekers through unequal opportunities of completing their undergraduate degrees in prestigious Chilean universities with high research capacity, and subsequently, the unequal opportunities of studying a doctorate degree at top-ranked foreign universities. Only upper social class candidates who received their doctorate degrees from foreign highly prestigious universities were capable of securing positions at the top research-intensive Chilean universities. Overall, findings show that academic networks with professors who are knowledgeable of hiring processes are crucial at the moment of seeking academic jobs in the Chilean higher education system.
- 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
Social and structural barriers related to menstruation across diverse schools in the Eastern Cape
- Macleod, Catriona I, Du Toit, Ryan, Paphitis, Sharli A, Kelland, Lindsay
- Authors: Macleod, Catriona I , Du Toit, Ryan , Paphitis, Sharli A , Kelland, Lindsay
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444385 , vital:74224 , xlink:href="https://hdl.handle.net/10520/ejc-educat-v40-n3-a9"
- Description: The barriers to education associatedwith menstruation vary from country to countryand within countries. We report on a cross-sectional survey conducted in diverse schools in 2districts of the Eastern Cape, South Africa. Using multi-stage sampling(stratified random sampling of schools, and purposive sampling of Grade 11 female-identifiediilearners), we accessed1,035 respondents with an average age of 17.2 years. Respondents completed a questionnaire developed from previous questionnaires and our readings of the literature. We report here on results pertaining to the social and structural barriers relatedto menstruation. Just over one fifth of young womeniiiacross the whole sample reported missing an average of 1.8 days of school per menstrual cycle, while a significant minority reportedrestrictions related to sporting and classroom activities. Results show, contrary to expectations, that young womenattending under-resourced schools report missing fewer days than young womenattending resourced schools, despite young womenin under-resourced schools experiencing inadequate sanitationfacilities and feeling unsafeusingthese facilities. This research indicates the importance of recognising social as well as structural features when considering the gendered barriers to education that menstruation may represent.
- Full Text:
- Date Issued: 2020
- Authors: Macleod, Catriona I , Du Toit, Ryan , Paphitis, Sharli A , Kelland, Lindsay
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444385 , vital:74224 , xlink:href="https://hdl.handle.net/10520/ejc-educat-v40-n3-a9"
- Description: The barriers to education associatedwith menstruation vary from country to countryand within countries. We report on a cross-sectional survey conducted in diverse schools in 2districts of the Eastern Cape, South Africa. Using multi-stage sampling(stratified random sampling of schools, and purposive sampling of Grade 11 female-identifiediilearners), we accessed1,035 respondents with an average age of 17.2 years. Respondents completed a questionnaire developed from previous questionnaires and our readings of the literature. We report here on results pertaining to the social and structural barriers relatedto menstruation. Just over one fifth of young womeniiiacross the whole sample reported missing an average of 1.8 days of school per menstrual cycle, while a significant minority reportedrestrictions related to sporting and classroom activities. Results show, contrary to expectations, that young womenattending under-resourced schools report missing fewer days than young womenattending resourced schools, despite young womenin under-resourced schools experiencing inadequate sanitationfacilities and feeling unsafeusingthese facilities. This research indicates the importance of recognising social as well as structural features when considering the gendered barriers to education that menstruation may represent.
- Full Text:
- Date Issued: 2020
SoTL: A mechanism for understanding and finding solutions to teaching and learning challenges
- Authors: Vorster, Jo-Anne A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445727 , vital:74419 , https://doi.org/10.36615/sotls.v4i2.149
- Description: The paper argues that the Scholarship of Teaching and Learning (SoTL) is a necessary strategy for mitigating the many teaching and learning challenges in South African higher education that prevent a large proportion of students from achieving academic success. Research suggests that well-structured and coordinated educational practices that are valued and supported by institutions are crucial for student success. While there exists a very useful body of scholarship on teaching and learning in higher education in South Africa, the persistently high levels of student failure and dropout across the system points to the need for more research into teaching and learning dilemmas in diverse institutional, disciplinary and classroom contexts. I argue that if more academics are to conduct SoTL, it has to be valued and supported by institutions and academic leaders. Even though more SoTL is needed to contribute to solving the many pedagogic dilemmas South African academics encounter, it is counter-productive to expect all academics to conduct SoTL. Rigorous SoTL requires immersion in educational ideas, concepts, theories and research processes. Many academics may not have the time or inclination to work in the area of SoTL, but I suggest that all must be scholarly teachers of their disciplines.
- Full Text: false
- Date Issued: 2020
- Authors: Vorster, Jo-Anne A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445727 , vital:74419 , https://doi.org/10.36615/sotls.v4i2.149
- Description: The paper argues that the Scholarship of Teaching and Learning (SoTL) is a necessary strategy for mitigating the many teaching and learning challenges in South African higher education that prevent a large proportion of students from achieving academic success. Research suggests that well-structured and coordinated educational practices that are valued and supported by institutions are crucial for student success. While there exists a very useful body of scholarship on teaching and learning in higher education in South Africa, the persistently high levels of student failure and dropout across the system points to the need for more research into teaching and learning dilemmas in diverse institutional, disciplinary and classroom contexts. I argue that if more academics are to conduct SoTL, it has to be valued and supported by institutions and academic leaders. Even though more SoTL is needed to contribute to solving the many pedagogic dilemmas South African academics encounter, it is counter-productive to expect all academics to conduct SoTL. Rigorous SoTL requires immersion in educational ideas, concepts, theories and research processes. Many academics may not have the time or inclination to work in the area of SoTL, but I suggest that all must be scholarly teachers of their disciplines.
- Full Text: false
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
Susceptibility of Staphylococcus aureus to porphyrin-silver nanoparticle mediated photodynamic antimicrobial chemotherapy
- Shabangu, Samuel M, Babu, Balaji, Soy, Rodah C, Ovim, James, Amuhaya, Edith K, Nyokong, Tebello
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Ovim, James , Amuhaya, Edith K , 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:
- Date Issued: 2020
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Ovim, James , Amuhaya, Edith K , 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
Synthesis and biological evaluation of bis-N2, N2′-(4-hydroxycoumarin-3-yl) ethylidene]-2, 3-dihydroxysuccinodihydrazides
- Manyeruke, Meloddy H, Tshiwawa, Thendamudzimu, Hoppe, Heinrich C, Isaacs, Michelle, Seldon, Ronnett, Warner, Digby F, Krause, Rui W M, Kaye, Perry T
- Authors: Manyeruke, Meloddy H , Tshiwawa, Thendamudzimu , Hoppe, Heinrich C , 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:
- Date Issued: 2020
- Authors: Manyeruke, Meloddy H , Tshiwawa, Thendamudzimu , Hoppe, Heinrich C , 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
The birds of Fort Fordyce Reserve, Eastern Cape
- Craig, Adrian J F K, Hulley, Patrick E
- Authors: Craig, Adrian J F K , Hulley, Patrick E
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449897 , vital:74862 , https://doi.org/10.15641/bo.v11i0.687
- Description: The avifauna of this forest reserve has been surveyed, based on observations and mist-netting over a ten-year period. We have recorded 175 species, of which 56 are considered" true" forest birds in this region. These include four summer migrants, and four occasional visitors; the others are likely to be resident. Four species of conservation concern, the Knysna Woodpecker, African Crowned Eagle, Lanner Falcon and Bush Blackcap probably nest within the protected area.
- Full Text:
- Date Issued: 2020
- Authors: Craig, Adrian J F K , Hulley, Patrick E
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449897 , vital:74862 , https://doi.org/10.15641/bo.v11i0.687
- Description: The avifauna of this forest reserve has been surveyed, based on observations and mist-netting over a ten-year period. We have recorded 175 species, of which 56 are considered" true" forest birds in this region. These include four summer migrants, and four occasional visitors; the others are likely to be resident. Four species of conservation concern, the Knysna Woodpecker, African Crowned Eagle, Lanner Falcon and Bush Blackcap probably nest within the protected area.
- Full Text:
- Date Issued: 2020
The conundrums of counselling women in violent intimate partner relationships in South Africa: implications for practice
- Fleischack, Anne, Macleod, Catriona I, Böhmke, Werner
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444117 , vital:74191 , xlink:href="https://doi.org/10.1007/s10447-019-09384-8"
- Description: Little research focuses on how counsellors experience counselling encounters concerning intimate partner violence. This study reports on narrative research conducted with eight South African non-governmental organisation counsellors. Participants spoke of creating productive and caring counselling dynamics, and providing non-directive counselling. However, they also indicated providing moral guidance, particularly in cases where pregnancy or children were involved. Success was viewed rather narrowly as the women leaving the relationship, setting up ‘all-or-nothing’ outcomes. Such ‘success’ led to counsellor happiness, whilst failure in this regard led to counsellors experiencing anger and burn-out. We conclude that the conundrums evident in these data are grounded in patriarchal systems, limiting the efficacy of counselling based on a bondage and deliverance narrative. Implications for practice and training are also outlined.
- Full Text:
- Date Issued: 2020
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444117 , vital:74191 , xlink:href="https://doi.org/10.1007/s10447-019-09384-8"
- Description: Little research focuses on how counsellors experience counselling encounters concerning intimate partner violence. This study reports on narrative research conducted with eight South African non-governmental organisation counsellors. Participants spoke of creating productive and caring counselling dynamics, and providing non-directive counselling. However, they also indicated providing moral guidance, particularly in cases where pregnancy or children were involved. Success was viewed rather narrowly as the women leaving the relationship, setting up ‘all-or-nothing’ outcomes. Such ‘success’ led to counsellor happiness, whilst failure in this regard led to counsellors experiencing anger and burn-out. We conclude that the conundrums evident in these data are grounded in patriarchal systems, limiting the efficacy of counselling based on a bondage and deliverance narrative. Implications for practice and training are also outlined.
- Full Text:
- Date Issued: 2020
The crystal structure of 2-oxo-2H-chromen-4-yl acetate, C11H8O4
- Hulushe, Siyabonga T, Manyeruke, Meloddy H, Hosten, Eric C, Kaye, Perry, Watkins, Gareth M
- Authors: Hulushe, Siyabonga 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:
- Date Issued: 2020
- Authors: Hulushe, Siyabonga 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020
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:
- Date Issued: 2020
- 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:
- Date Issued: 2020