Borneol-triarylcorrole hybrids with chiral-optical response and anticancer behaviours
- Authors: Fu, Bo , Wang, Lin , Yu, Xiaoxiao , Fang, Xianying , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu , Xu, Haijun
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185294 , vital:44362 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109699"
- Description: A series of four multifunctional A2B type H3corroles with meso-borneol substituents at the B position have been synthesized and characterized. A detailed analysis of the optical properties was carried out, and a comparison was made with theoretical calculations to identify the key trends in the structure-property relationships. The meso-borneol substituent couples with the corrole core leading to clear CD signals in the B band region. Enhanced anti-cancer properties are observed in vitro relative to (−)-borneol with cell inhibition rates of up to 94%.
- Full Text:
- Date Issued: 2021
Cereal stem borer (Lepidoptera) assemblage structure in a sub-tropical agro-ecosystem, Eastern Cape Province, South Africa
- Authors: Niba, AS. , Mdazu, S.
- Date: 2021
- Subjects: Cereal products Stem borers Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6958 , vital:52619 , xlink:href="https://doi.org/10.1080/0035919X.2021.1893861"
- Description: Insect pests, especially lepidopterous stem borers, cause significant losses to cereal production at local and global scales. The borer species associated with cultivated grain cereals and alternative wild host plants were identified at three elevation gradients in the former Transkei area of the Eastern Cape Province, South Africa. Stem borer sampling was undertaken during maize crop and non-crop seasons in Port St Johns (PSJ), Mthatha and Elliot, sites that differ in elevation above sea level, annual precipitation and temperature. Morphologically identical borers retrieved from each sampling unit were recorded, processed and reared to adult stage for identification at an ambient temperature range of 25–28°C and a relative humidity range of 65–80%. Specimens were sorted first into morphospecies (MS1–MS6) based on external morphological characteristics. Six stem borer species (Busseola fusca, Sesamia calamistis, Eldana saccharina, Chilo orichalcocili, Chilo sacchariphagus and Chilo partellus) were collected during the survey. E. saccharina and C. orichalcocili were absent in PSJ; in Elliot, E. saccahrina occurred in very low numbers whereas C. partellus was absent. Busseola fusca was more abundant at high altitude (i.e. Elliot). Borer community structure in the study showed similarity between Mthatha and Elliot. Species richness and abundance across study sites were not statistically significant (P > 0.05). The study provides information on borer species occurrence in the study area, and techniques to identify larval stages for effective control by local farmers and extension workers. When designing strategies for borer control, elevation may not be a major concern at this spatial scale.
- Full Text:
- Date Issued: 2021
Cereal stem borer (Lepidoptera) assemblage structure in a sub-tropical agro-ecosystem, Eastern Cape Province, South Africa
- Authors: Niba, AS. , Mdazu, S.
- Date: 2021
- Subjects: Cereal products Stem borers Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6948 , vital:52620 , xlink:href="https://doi.org/10.1080/0035919X.2021.1893861"
- Description: Insect pests, especially lepidopterous stem borers, cause significant losses to cereal production at local and global scales. The borer species associated with cultivated grain cereals and alternative wild host plants were identified at three elevation gradients in the former Transkei area of the Eastern Cape Province, South Africa. Stem borer sampling was undertaken during maize crop and non-crop seasons in Port St Johns (PSJ), Mthatha and Elliot, sites that differ in elevation above sea level, annual precipitation and temperature. Morphologically identical borers retrieved from each sampling unit were recorded, processed and reared to adult stage for identification at an ambient temperature range of 25–28°C and a relative humidity range of 65–80%. Specimens were sorted first into morphospecies (MS1–MS6) based on external morphological characteristics. Six stem borer species (Busseola fusca, Sesamia calamistis, Eldana saccharina, Chilo orichalcocili, Chilo sacchariphagus and Chilo partellus) were collected during the survey. E. saccharina and C. orichalcocili were absent in PSJ; in Elliot, E. saccahrina occurred in very low numbers whereas C. partellus was absent. Busseola fusca was more abundant at high altitude (i.e. Elliot). Borer community structure in the study showed similarity between Mthatha and Elliot. Species richness and abundance across study sites were not statistically significant (P > 0.05). The study provides information on borer species occurrence in the study area, and techniques to identify larval stages for effective control by local farmers and extension workers. When designing strategies for borer control, elevation may not be a major concern at this spatial scale.
- Full Text:
- Date Issued: 2021
Constraints on improving higher education teaching and learning through funding
- Authors: Moyo, Temwa , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185854 , vital:44440 , xlink:href="http://dx.doi.org/10.17159/sajs.2021/7807"
- Description: In the midst of massification, targeted funding has been used in various countries to address inefficiencies in teaching and learning. In South Africa, arguments have been made for significant investments to be made and the University Capacity Development Grant (UCDG) in particular is being used as a driver for improved outputs. Prior to its implementation in 2018, the UCDG comprised the Research Development Grant and the Teaching Development Grant. The Teaching Development Grant was intended to address low retention and throughput rates and ZAR5.5 billion was spent to this end over a 12-year period. The analysis presented here of all Teaching Development Grant budget plans and progress reports from 2007 to 2015 shows that the undifferentiated implementation of the Teaching Development Grant within a differentiated sector limited its potential for system-wide gains. Institutions without adequate resources tended to divert Teaching Development Grant funds to attend to backlogs rather than to address teaching and learning practices and such universities lost much of their allocation through the withholding of unspent funds. This blanket practice addressed the symptoms of underspending but not the structural, cultural and agential mechanisms that led to such under-expenditure. Uneven access to the limited teaching development expertise also impacted on the use of the grant. This call for a context-based approach to funding has been identified as a key success factor in grant interventions in both African and European universities. We recommend a sector-wide response in the form of a national body or plan for the benefit of all universities and investment in financial management enhancement. The study contributes to a better understanding of how government funding interventions can achieve intended goals. The study calls for a more contextualised approach to funding and to greater collaboration across the sector to maximise limited capacity.
- Full Text:
- Date Issued: 2021
Disilane-bridged architectures with high optical transparency for optical limiting
- Authors: Feng, Hongjie , Zhou, Zhikuan , May, Aviwe K , Chen, Jiaying , Mack, John , Nyokong, Tebello , Gai, Lizhi , Lu, Hua
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190623 , vital:45011 , xlink:href="https://doi.org/10.1039/D1TC01488A"
- Description: A novel tetraphenylethylene (TPE) architecture that makes use of a disilane bridge was developed to successfully prepare organic optical power limiting (OPL) materials with high transparency. The σ-bridged TPE derivatives exhibit enhanced solid-state emission efficacies up to 4 times that of TPE. Due to the unique σ-electron delocalization, the incorporated Si–Si bridge gives rise to intense nonlinear optics (NLO) properties. These compounds show favorable optical transparency in the visible region, since the σ–π interaction has a relatively minor effect on the absorption properties of TPE. The poly(bisphenol A carbonate) (PBC) thin films of disilane-bridged compounds exhibit significant reverse saturable absorbance (RSA) responses during Z-scan measurements at 532 nm. In contrast, negligible OPL properties were observed in tetrahydrofuran (THF) solution and when a PBC thin film was prepared with TPE. The disilane-bridged molecular system represents a novel and easily prepared architecture for the construction of solid-state optical limiting materials.
- Full Text:
- Date Issued: 2021
Nothing forever
- Authors: Krueger, Anton
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225533 , vital:49233 , xlink:href="https://doi.org/10.5920/pam.1013"
- Description: Thank you to everybody who made contributions to this bumper 2021 Special Issue on Improvisation. Many thanks to our peer reviewers and especially to co-editors Deborah and Daniel for their help with the selection and editing process which has now culminated in a baker’s dozen texts. With contributions from Australia, South Africa, and New Zealand, as well as from France, the USA and the UK, the issue includes five interviews, four articles, two book reviews, a reflection and a score.
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- Date Issued: 2021
Preformulation characterization and identification of excipients for nevirapine loaded niosomes
- Authors: Witika, Bwalya A , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183126 , vital:43914 , xlink:href="https://doi.org/10.1691/ph.2021.0137"
- Description: Nevirapine (NVP) is used for the management of HIV/AIDS but must be dosed frequently, exhibits unpredictable bioavailability and a side effect profile that includes hepato- and dermo-toxicity. Niosomes are a colloidal drug delivery system that may be used to overcome the low bioavailability, side effect profile and frequent dosing needed when using conventional drug delivery systems. The compatibility of NVP with sorbitan esters, polysorbate, cholesterol and dihexadecyl phosphate (DCP) was investigated using Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red Spectroscopy (FTIR) and X-ray Powder Diffraction (XRPD). Screening studies were undertaken to identify potential excipients that would produce niosomes with target critical quality attributes (CQA) viz, a particle size (PS) less than 1000 nm, a polydispersity index (PDI) less than 0.500 and an entrapment efficiency greater than 90%. The results revealed that sorbitan esters in combination with cholesterol and 5 μmol DCP produced niosomes with the best CQA and Zeta potential (ZP) less than -30 mV which suggests good stability of the niosomes on storage. Sorbitan esters produced the smallest niosomes of less than 400 nm diameter with a PDI less than 0.400 and an entrapment efficiency of more than 78% without cholesterol. The addition of cholesterol and DCP was essential to form niosomes with target CQA.
- Full Text:
- Date Issued: 2021
Sustainable Human Resource Practices for Organizational Competitiveness Post the Covid-19 Pandemic
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Personel Management Covid-19 (Disease) Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8118 , vital:61396 , xlink:href="https://www.abacademies.org/articles/Sustainable-human-resource-practices-for-organizational-competitiveness-post-the-covid-19-1528-2686-27-2-480.pdf"
- Description: The study was formulated to tap into the future of HRM given the disruptions arising from the Covid-119 pandemic as well as the progression of the global technological environment to the fourth industrial revolution. The aim of the study was to: the Covid-19 induced HRM practices underpinning future organizational competitiveness. A literature review strategy was adopted to achieve the study objective. The study established seven emerging themes to inform HRM practices for the competitiveness of organizations in future following the Covid-19 disturbances. These themes are: primacy of HRM, increased cyber influences, digitalization, remote HRM, human-machine interface skills, human-organisation strategic links as well as human-technology interface competencies. Based on the study findings, the study recommended HRM departments to move to HR 4.0 through the adoption of industry 4.0 technologies, increased automation, and digitalization as well as strengthen virtualization systems.
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- Date Issued: 2021
The potential influence of commercial plant nurseries in shaping the urban forest in South Africa
- Authors: Arnoldi, Marco , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398408 , vital:69409 , xlink:href="https://doi.org/10.1016/j.ufug.2021.127254"
- Description: A substantial portion of urban green infrastructure is under private tenure in residents’ and business/corporate gardens. Therefore, the ways that urban residents manage their gardens can influence the type, quantity and quality of ecosystem services and disservices in urban areas. Plant nurseries are a major source of trees for urban residents, and so the types of trees and species that nurseries stock influence the composition of private gardens. Consequently, this study aimed to examine the roles that plant nurseries play in shaping the urban forest in South Africa. To do so, an online and direct questionnaire was used to gather data from 30 nurseries across 19 urban centres in South Africa. The main questions included species selection criteria, customer tree inquiries, best-selling tree species, attitudes towards increasing urban tree cover and diversity and whether they think climate change will affect the selection of species to stock. The results show that there is a strong preference for indigenous trees, which were also most commonly listed as best-sellers. Non-native species that were commonly sold were ones that provided provisioning services, particularly edible fruits. Drought tolerance influenced selection criteria and customer demand. Vachellia spp. and Olea europaea were commonly inquired about and most commonly listed amongst the best-sellers. Nursery owners valued the importance of increasing tree cover and diversity in urban areas, listing many perceived benefits for doing so. We conclude that there is a clear preference for indigenous tree species by customers and nursery owners, which in time could increase the proportion and cover of native species.
- Full Text:
- Date Issued: 2021
The role of causal knowledge in stigma considerations in African genomics research
- Authors: Matshabane, Olivia P , Campbell, Megan , Appelbaum, Paul S , Marshall, Patricia A , Stein, Dan J , de Vries, Jantina
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302578 , vital:58209 , xlink:href="https://doi.org/10.1016/j.socscimed.2021.113902"
- Description: Introduction: Advances in genomics research have raised several ethical concerns. One concern is the potential impact of genomics research on stigma experienced by people affected by a disease. Studies have found that the type of illness as well as disease causal beliefs impact on the relation between genetic attribution and stigma. This study explored the potential impact of genetic attribution of disease on stigma among Xhosa people with Rheumatic Heart Disease (RHD). Methods: Study participants were 46 Xhosa people with RHD living in the Western Cape Province of South Africa. Using video vignettes in 7 focus group discussions we explored whether and how genetic attribution may impact on disease-stigma. Vignettes introduced participants to non-genetic and genetic causal explanations and were followed-up with a series of open-ended questions eliciting their perceptions of non-genetic disease causes as well as genetic causation and its impact on internalised stigma. Results: This study found that Xhosa people with RHD have a general understanding of genetics and genetic attribution for disease. Additionally, and not withstanding their genetic knowledge, these participants hold multiple disease causal beliefs including genetic, infectious disease, psychosocial, behavioural and cultural explanations. While there was evidence of internalised stigma experiences among participants, these appeared not to be related to a genetic attribution to the disease. Discussion: The findings of this study provide clues as to why it is unlikely that a genetic conceptualisation of disease impacts internalised stigma experiences of Xhosa people. The causal explanations provided by participants reflect their cultural understandings and their context, namely, living in low-income and poverty-stricken environments. Divergence in these findings from much of the evidence from high-income countries emphasises that context matters when considering the impact of genetic attribution on stigma and caution against generalising findings from one part of the globe to another.
- Full Text:
- Date Issued: 2021