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Photodynamic inactivation of methicillin-resistant Staphylococcus aureus using pyrrolidinium containing Schiff base phthalocyanines

  • Authors: Sindelo, Azole , Sen, Pinar , Nyokong, Tebello
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/360449 , vital:65089 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114535"
  • Description: New tetra-substituted zinc and indium Schiff base phthalocyanines (ZnPc and InPc, respectively) are synthesized and characterized herein. The ethyl pyrrolidine (ZnPc-2, InPc-2) and propyl pyrrolidine (ZnPc-3, InPc-3) substituted Schiff base Pcs were reacted with methyl iodide to form their cationic derivatives (ZnPc-2Q, InPc-2Q, ZnPc-3Q, and InPc-3Q, respectively). The photophysical and photochemical properties of the Pcs were studied. The cationic Pcs generated higher singlet oxygen quantum yield in aqueous media than the neutral Pcs. The photoinactivation of Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) strains was evaluated. 5 µM ZnPc-3Q and InPc-3Q inactivated 100 % of the MSSA and MRSA while 5 µM ZnPc-2Q and InPc-2Q eradicated 100 % for MSSA and 97.2 % and 98.7 % (respectively) of the MRSA. The photodynamic antimicrobial chemotherapy studies depended on singlet oxygen ability, the charges, and the extension of the alkyl groups.
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  • Date Issued: 2023

Rationalising the retro-Diels-Alder fragmentation pattern of viscutins using electrospray interface-tandem mass spectrometry coupled to theoretical modelling

  • Authors: Moyo, Babra , Novokoza, Yolanda , Tavengwa, Nikita T , Kuhnert, Nikolai , Lobb, Kevin A , Madala, Ntakadzeni E
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452786 , vital:75170 , xlink:href="https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9592"
  • Description: Although mass spectrometry (MS) is a powerful tool in structural elucidation of unknown flavonoids based on their unique fragmentation patterns, proposing the correct fragmentation mechanism is still a challenge from tandem mass spectrometry data only. In recent years, computational tools such as molecular networking and MS2LDA have played a major role in the identification of structurally related compounds through an in-depth survey of their fragmentation patterns.
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  • Date Issued: 2023

A simple quinoline-thiophene Schiff base turn-off chemosensor for Hg2+ detection

  • Authors: Musikavanhu, Brian , Muthusamy, Selvaraj , Zhu, Dongwei , Xue, Zhaoli , Yu, Qian , Chivumba, Choonzo N , Mack, John , Nyokong, Tebello , Wang, Shengjun , Zhao, Long
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/230362 , vital:49771 , xlink:href="https://doi.org/10.1016/j.saa.2021.120338"
  • Description: A new Schiff base probe (QT) consisting of 8-aminoquinoline (Q) and thiophene-2-carboxaldehyde (T) moieties has been synthesized. QT undergoes chelation-enhanced fluorescence quenching when exposed to Hg2+ due to coordination by the sulfur and nitrogen atoms of QT thus forming a facile “turn-off” sensor. The formation of the chelation complex was confirmed by UV–visible absorption and emission spectral measurements, 1H NMR titration and density functional theory calculations. These studies revealed that the probe exhibits high selectivity and sensitivity towards Hg2+ in the presence of other common metal ions. A low detection limit of 23.4 nM was determined and a Job plot confirmed a 2:1 stoichiometry between QT and Hg2+. The potential utility of QT as a sensor for Hg2+ ions in human HeLa cells was determined by confocal fluorescence microscopy, and its suitability for use in the field with environmental samples was tested with Whatman filter paper strips.
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  • Date Issued: 2022

Beyond epistemology: the challenge of reconceptualising knowledge in higher education

  • Authors: Luckett, Kathy , Blackie, Margaret A L
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/426598 , vital:72371 , xlink:href="https://doi.org/10.1080/13562517.2022.2111206"
  • Description: In this Point of Departure, we build on the scholarship of Suellen Shay. Shay explored the nature of higher education, examining assessment and the relation between curriculum and knowledge structures across several disciplines. She drew on the work of Bernstein and in her later work responded to the calls for decolonisation. We first contextualise the work of Basil Bernstein and explain its attraction for scholars of education development in the South African HE context. We then provide a brief summary of recent decolonial scholarship. On this basis, we speculate what a critique and caricature of the Bernsteinian tradition by the decolonial school might look like. In turn we offer a caricatured rebuttal by the Bernsteinian school to the decolonial critique. Finally, we pull our argument together and, by drawing on Bhaskar’s critical realism, assert the importance of an adequate theorisation of ontology.
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  • Date Issued: 2022

Climatic suitability and compatibility of the invasive Iris pseudacorus L.(Iridaceae) in the Southern Hemisphere: Considerations for biocontrol

  • Authors: Minuti, Gianmarco , Stiers, Iris , Coetzee, Julie A
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/423293 , vital:72045 , xlink:href="https://doi.org/10.1016/j.biocontrol.2022.104886"
  • Description: Iris pseudacorus L. (Iridaceae) is an emergent macrophyte native to Europe, North Africa and western Asia. Considered invasive in wetland habitats around the world, this species is now the target of a biocontrol programme in the Southern Hemisphere. Native range surveys of the weed led to the selection of the flea beetle, Aphthona nonstriata Goeze (Coleoptera: Chrysomelidae), as a candidate biocontrol agent. An important aspect to consider in weed biocontrol is the ability of an agent to establish and thrive in the environment where it is released. Climatic incompatibility between source and intended release sites can in fact limit the success of a biocontrol programme. In the current study, the potential climatic niche of I. pseudacorus and A. nonstriata in the Southern Hemisphere was analysed. The ecological niche modelling software MaxEnt was used to map the climatic suitability of both organisms across invaded regions in South America, southern Africa and Australasia. Furthermore, occurrence records from each invaded range were used independently to model the climatic compatibility of I. pseudacorus in Europe, in order to prioritize areas of the native range to explore during future surveys for potential biocontrol agents. The models identified areas at high risk of invasion by I. pseudacorus in northern Argentina, Uruguay, southern Brazil and central Chile, as well as numerous provinces of eastern South Africa, Lesotho, southern Australia and New Zealand. Accordingly, the highest climatic suitability for A. nonstriata was predicted across the humid temperate climates of north-east Argentina, Uruguay, southern Brazil, southern South Africa, south-east Australia and New Zealand. These results can eventually be used in future release plans to prioritize areas where establishment and survival of the agent is expected to be highest. At the same time, it may be useful to search the native range of the weed for biological control agents showing high climatic adaptation towards the intended release sites of each invaded range. In this regards, our climatic compatibility models identified high-priority areas across the Mediterranean regions of Italy and southern France, as well as the temperate regions of central and western Europe. Altogether, the current study provides useful new information to tackle the invasion and advance the biocontrol programme of I. pseudacorus in the Southern Hemisphere.
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  • Date Issued: 2022

Drug Resistance in the HIV-1 Subtype C Protease Enzyme: A High Throughput Virtual Screening Approach in Search of New Ligands with Activity

  • Authors: Sarron, Arthur F D , Lobb, Kevin A
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452699 , vital:75163 , xlink:href="10.2174/1871520622666220202161543"
  • Description: Background: HIV-1 subtype C protease is a strategic target for antiretroviral treatment. However, resistance to protease inhibi-tors appears after months of treatment. Chromones and 2- bis-coumarin derivatives show potential for inhibition of the HIV- subtype C protease. Objective: Different heterocyclic structures from the ZINC database were docked against Human Immuno-deficiency Virus-1 (HIV) subtype C protease crystal structure 2R5Q and 2R5P. The 5 best molecules were selected to be docked against 62 homology models based on HIV-protease se-quences from infants failing antiretroviral protease treatment. This experimentation was performed with two molecular docking programs: Autodock and Autodock Vina. These molecules were modified by substituting protons with different moieties, and the derivatives were docked against the same targets. Ligand-protein interactions, physical/chemical proprieties of the mole-cules, and dynamics simulations were analyzed.
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  • Date Issued: 2022

Ga III triarylcorroles with push–pull substitutions

  • Authors: Niu, Yingjie , Wang, Lin , Guo, Yingxin , Zhu, Weihua , Soy, Rodah C , Babu, Balaji , Mack, John , Nyokong, Tebello , Xu, Haijun , Liang, Xu
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/300079 , vital:57890 , xlink:href="https://doi.org/10.1039/D2DT01262F"
  • Description: Two A2B type H3corroles and two GaIIItriarylcorroles with carbazole substitutions at 10-positions were synthesized and characterized. An analysis of structure–property relationships of the corroles has been carried out by investigating the optical spectroscopy of the dyes to trends predicted in DFT and TD-DFT calculations. Interestingly, the photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT) activity properties of the GaIIItriarylcorroles were determined against the MCF-7 breast cancer line, and Staphyloccocus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The cationic G-2Q species exhibited the most favorable properties with an IC50 value of 7.8 μM against MCF-7 cells, and Log reduction values of 7.78 and 3.26 against planktonic S. aureus and E. coli at 0.5 and 10 μM, respectively.
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  • Date Issued: 2022

How many people globally actually use non-timber forest products?

  • Authors: Shackleton, Charlie M , de Vos, Alta
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/403200 , vital:69933 , xlink:href="https://doi.org/10.1016/j.forpol.2021.102659"
  • Description: Non-timber forest products (NTFPs) are widely used wild, biological products harvested from rural and urban landscapes for household subsistence, income and culture, thereby contributing to human wellbeing. Estimates of the numbers of people making use of, or being dependent on, NTFPs vary widely, and global estimates to date have excluded urban populations and also NTFP users in the Global North. Additionally, most global or continental estimates are two or more decades old, and hence do not account for significant worldwide changes in societies, cultures, economies and landscapes since the estimates were made. Here we collate more recent empirical studies reporting the number of NTFP users at fine scales that we extrapolate up for three broad regions, viz. rural areas of the Global South, urban areas of the Global South, and the Global North, as the basis for estimating the number of NTFP users globally. We calculate the lower and upper bounds, as well a median estimate. We find the lowest and median approximations to be 3.5 billion and 5.76 billion users globally, respectively, based on conservative approaches. This is more than double and triple, respectively, the oft cited and dated figure of 1.6 billion. Moreover, we find that only half of the global NTFP users are located in rural regions of the Global South, and that the other half are in urban areas and the Global North, showing that NTFPs are of importance across socio-economic and geographic regions, not just in remote and underdeveloped villages of the Global South. With such large numbers of users around the world, it is imperative that the supply, management, conservation and safeguarding of the values of NTFPs take a more central place in sectoral and development policies.
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  • Date Issued: 2022

Indium phthalocyanines

  • Authors: Pinar, Sen , Mack, John , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/229998 , vital:49731 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.131850"
  • Description: In this study, the photodynamic antimicrobial activities of a series of new tetra-substituted indium phthalocyanine (InPc) complexes are assessed. An aldehyde substituted complex (2) was initially prepared, which was converted through a condensatioreaction to an imine-pyrrolidine substituted complex (3), which in turn was quaternized to form a tetracationic species (4). Favorable photophysicochemical properties were obtained by incorporating a heavy In(III) ion into the central cavity. Aggregation studies revealed that 2–4 remain non-aggregated in DMSO at concentration below 25 µM. The photodeactivation of S.aureus and E.coli was studied. Log reduction values > 9.0 were obtained for cationic InPc 4 after 30 min of incubation and exposure to light for 75 min.
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  • Date Issued: 2022

Is the instrumental approach a ‘silver bullet’for addressing non-compliance in recreational fisheries: A South African case study

  • Authors: Bova, Christopher S , Stephens, Jed , Aswani, Shankar , Potts, Warren M
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/391359 , vital:68644 , xlink:href="https://doi.org/10.1016/j.fishres.2022.106439"
  • Description: Non-compliance with recreational fishery regulations is considered to be one of the biggest threats to the sustainability of fisheries. Dedicated non-compliance studies are seldom carried out at the national level which makes it difficult to discern the behavioural compliance norms within a population. The instrumental approach for compliance is the traditional paradigm in recreational fisheries. It postulates that increased enforcement activities and the corresponding punishment will improve compliance behaviour, although there is little empirical evidence for such a supposition within the recreational fisheries context. Using face-to-face encounter surveys employing the ballot box method for reducing social desirability bias (SDB), South African marine shore-based fishery (MSBF) participants were questioned on their compliance behaviour with a set of regulations pertaining to the fishery. Overall non-compliance levels were very high (52%), and non-compliance levels with individual regulations varied based on provincial locality. Perceptions and observations of enforcement activity had no significant impact on compliance behaviour. Participants that had previously been caught by law enforcement violating the regulations were still more likely to violate the regulations than participants that had not faced enforcement action. Results indicate that calls for increased enforcement as a means of improving compliance behaviour are questionable in the South African MSBF, and further emphasise the need to develop alternative approaches, such as those pertaining to normative theory, within recreational fisheries.
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  • Date Issued: 2022

Solvent promoted tautomerism in thione-containing tetraazatricyclics: evidence from 1H NMR spectroscopy and transition state studies

  • Authors: Odame, Felix , Tshentu, Zenixole R , Lobb, Kevin A
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/453198 , vital:75230 , xlink:href="https://link.springer.com/article/10.1007/s00894-022-05204-w"
  • Description: Tautomerism in the nitro substituted thione-containing traazatricyclics has been investigated. Evidence from 1 H NMR indicating the existence of the tautomers has been augmented with computational studies providing evidence of the stability or otherwise of these tautomers. The role of water and DMSO in the formation of the tautomers has been explained. The role of the nitro group in assisting in the formation of the tautomers has been discussed.
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  • Date Issued: 2022

The molecular basis of the effect of temperature on the structure and function of SARS-CoV-2 spike protein

  • Authors: Khan, Faez I , Lobb, Kevin A , Lai, Dakun
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/453223 , vital:75232 , xlink:href="https://doi.org/10.3389/fmolb.2022.794960"
  • Description: The remarkable rise of the current COVID-19 pandemic to every part of the globe has raised key concerns for the current public healthcare system. The spike (S) protein of SARS-CoV-2 shows an important part in the cell membrane fusion and receptor recognition. It is a key target for vaccine production. Several researchers studied the nature of this protein under various environmental conditions. In this work, we applied molecular modeling and extensive molecular dynamics simulation approaches at 0°C (273.15 K), 20°C (293.15 K), 40°C (313.15 K), and 60°C (333.15 K) to study the detailed conformational alterations in the SARS-CoV-2 S protein. Our aim is to understand the influence of temperatures on the structure, function, and dynamics of the S protein of SARS-CoV-2. The structural deviations, and atomic and residual fluctuations were least at low (0°C) and high (60°C) temperature. Even the internal residues of the SARS-CoV-2 S protein are not accessible to solvent at high temperature. Furthermore, there was no unfolding of SARS-CoV-2 spike S reported at higher temperature. The most stable conformations of the SARS-CoV-2 S protein were reported at 20°C, but the free energy minimum region of the SARS-CoV-2 S protein was sharper at 40°C than other temperatures. Our findings revealed that higher temperatures have little or no influence on the stability and folding of the SARS-CoV-2 S protein.
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  • Date Issued: 2022

The synergistic effects of coupling Au nanoparticles with an alkynyl Co (II) phthalocyanine on the detection of prostate specific antigen

  • Authors: Nxele, Siphesihle Robin , Nkhahle, Reitumetse , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/230232 , vital:49756 , xlink:href="https://doi.org/10.1016/j.talanta.2021.122948"
  • Description: Prostate specific antigen (PSA) aptasensors are fabricated using a novel asymmetrically substituted Co phthalocyanine (CoPc), gold nanoparticles (AuNPs) and PSA-specific antigen. The fabricated aptasensors are: GCE-AuNPs-Aptamer, GCE@CoPc-Aptamer and GCE-AuNPs@CoPc-Aptamer (GCE = glassy carbon electrode). The fabricated sensors are characterized at each modification step to monitor the changes occurring at the sensor surface. Concentration studies were carried out using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) to determine detection limits. All the fabricated aptasensors were found to be highly specific and selective but the GCE-AuNPs@CoPc-Aptamer nanoconjugate performed the best. The aptasensors were also tested in spiked serum samples and detection limits, as well as % recoveries were determined. The results obtained showed that the GCE-AuNPs@CoPc-Aptamer has the potential to be used for clinical studies as the results agree with those obtained for detection of PSA in buffer.
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  • Date Issued: 2022

Trees stocks in domestic gardens and willingness to participate in tree planting initiatives in low-cost housing areas of the Eastern Cape, South Africa

  • Authors: Gwedla, Nanamhla , Shackleton, Charlie , Olvitt, Lausanne L
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/372825 , vital:66626 , xlink:href="https://doi.org/10.1016/j.ufug.2022.127484"
  • Description: Increasing human populations and rapid urbanization in sub-Saharan Africa have prompted the development and maintenance of urban green infrastructure, including urban trees for sustainability, human wellbeing, liveability and climate resilience. However, there are still insufficient amounts and large inequities in the distribution of trees between and within towns and cities of the Global North and South. In South Africa, urban green space planning and planting are encoded in several policies at national level. However, these policies are rarely translated into specific guides, standards or actions, and consequently disparities in urban trees and green space distribution persist. This study assessed the prevalence of urban trees in domestic gardens in low-cost housing areas (LCHAs) of eight small to medium-sized towns in the Eastern Cape province of South Africa and examined residents’ perceptions in this regard. This was done via surveys with 800 households in old and recently developed LCHAs. The results revealed that most households (52 %) had at least one tree in their yard, with more households in the older neighbourhoods (60 %) reporting having trees than in the newer ones (44 %). Most of the trees (66 %) had been deliberately planted as opposed to natural regeneration. Experience of formal urban tree planting programs was low, but 75 % of residents expressed willingness to participate in the future, preferably in tree planting and maintenance. Urban green spaces and trees cannot be an afterthought in the development of sustainable human settlements, and municipal plans should reflect tangible commitments in this regard. Meeting goals for greener LCHAs requires the involvement of local residents, and for municipal authorities to be receptive to the wishes of residents and willingness to green their residential areas.
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  • Date Issued: 2022

Ultrasensitive detection of prostate-specific antigen using glucose-encapsulated nanoliposomes anti-PSA polyclonal antibody as detection nanobioprobes

  • Authors: Mwanza, Daniel , Mfamela, Nololo , Adeniyi, Omotayo , Nyokong, Tebello , Mashazi, Philani N
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/300268 , vital:57911 , xlink:href="https://doi.org/10.1016/j.talanta.2022.123483"
  • Description: In this work, the preparation of glucose encapsulating nanoliposomes was achieved using two different lipid formulations, labelled as F1 and F2. Both formulations contained phosphatidylcholine (PC), oleylamido-4-butanoic acid (OABA) and in addition, F1 had cholesterol (CHO) while F2 contained cholesteroyl hemisussinate (CHEMS). These formulations were studied for their pH sensitivity and controlled release of encapsulated glucose for indirect detection of prostate-specific antigen (PSA) using sandwich immunoassay. As a signal generator, encapsulated glucose in nanoliposomes was quantified directly using the personal glucose meter (PGM) and colorimetrically using peroxidase property of horseradish peroxidase (HRP) enzyme and Pd|PdO as nanozymes. Controlled release of the encapsulated glucose was achieved using the pH effect or Triton-X 100 as a surfactant to destabilize the liposomal structure. The F2 formulation showed maximum controlled release at acidic phosphate buffer saline (PBS, pH 5.0). The concentration of encapsulated glucose was found to be high in F2 formulation and these were applied for the indirect detection of PSA. The limit of detection (LOD) values for PSA were found to be 53 fg mL−1, 64 fg mL−1 and 10 fg mL−1 when HRP, Pd|PdO and PGM were respectively used. The detection signal was linear over a wide concentration range for PSA including the clinical range of 4–10 ng mL−1. The HRP system showed low LOD value when compared with Pd|PdO nanozymes. PGM system gave lowest LOD values owing to the sensitivity of the system towards glucose. Pd|PdO nanozyme system showed good stability over a wide temperature up to 80 °C. PGM system required less reaction time (2 min), low reagents and results were readily generated in digital format.
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  • Date Issued: 2022

COVID-19 and the future of work and organisational psychology

  • Authors: Pérez-Nebra, Amalia , Sklaveniti, Chrysavgi , Islam, Gazi , Petrović, Ivana , Pickett, Jennifer , Alija, Makfire , Matthijs Bal, P , Tekeste, Milena , Vukelić, Milica , Bazana, Sandiso , Sanderson, Zoe
  • Date: 2021
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/453742 , vital:75282 , xlink:href="http://dx.doi.org/10.4102/sajip.v47i0.1854"
  • Description: ORIENTATION: The coronavirus disease 2019 (COVID-19) pandemic has caused a 'coronafication' of research and academia, including the instrumentalisation of academic research towards the demands of society and governments. Whilst an enormous number of special issues and articles are devoted on the topic, there are few fundamental reflections on how the current pandemic will affect science and work and organisational psychology in the long run. RESEARCH PURPOSE: The current overview, written by a group of members of the Future of Work and Organisational Psychology (FOWOP) Movement, focuses on the central issues relating to work and organisational psychology that have emerged as a result of the COVID-19 crisis.
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  • Date Issued: 2021

Electrografting of isophthalic acid monolayer and covalent attachment of antibody onto carbon surfaces

  • Authors: Mwanza, Daniel , Phal, Sereilakhena , Nyokong, Tebello , Tesfalidet, Solomon , Mashazi, Philani N
  • Date: 2021
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/231345 , vital:49879 , xlink:href="https://doi.org/10.1016/j.electacta.2021.139360"
  • Description: In this study, a 5-diazonium isophthalic acid was synthesized and electrografted onto glassy carbon (GCE) and screen-printed carbon (SPCE) electrodes. SPCE was used to demonstrate fabrication of a miniature device and to compare with conventional glassy carbon electrodes. The isophthalic acid (IPA) electrografted thin film was used for the immobilization of anti-methotrexate antibody (Ab) using carbodiimide activation chemistry to form antibody modified surfaces, GCE-IPA-Ab and SPCE-IPA-Ab. The GCE -IPA-Ab and SPCE-IPA-Ab surfaces were used as capacitive biosensors for the detection of methotrexate (MTX) in phosphate buffer (pH 7.4) using capacitive electrochemical impedance spectroscopy (EIS). The EIS data was analyzed using singular value decomposition (SVD). Principal component regression analysis gave R2 values of 0.99 for both the GCE-IPA-Ab and SPCE-IPA-Ab surfaces. The detection limit from the calibration curve of the GCE-IPA-Ab and SPCE-IPA-Ab was calculated to be 7.0 pmol.L−1 and 5.5 pmol.L−1, respectively.
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  • Date Issued: 2021

Evaluating Community Engagement Strategies to Manage Stigma in Two African Genomics Studies Involving People Living with Schizophrenia or Rheumatic Heart Disease

  • Authors: Campbell, Megan M , Matshabane, Olivia P , Mqulwana, Sibonile , Mndini, Michael , Nagdee, Mohammed , Stein, Dan J , de Vries, Jantina
  • Date: 2021
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/302475 , vital:58199 , xlink:href="https://doi.org/10.1155/2021/9926495"
  • Description: In global health research and genomics research specifically, community engagement has gained prominence in enhancing ethical conduct, particularly in managing the risk of stigmatization, but there is minimal scientific evidence on how to do this effectively. This article reports on community engagement evaluation strategies in two African genomics studies: the Stigma in African Genomics Research study and the Genomics of Schizophrenia in South African Xhosa People (SAX) study. Within the Stigma in African Genomics Research study, a self-report rating scale and open-ended questions were used to track participant responses to an experiential theatre workshop. The workshop focused on participant experiences of living with schizophrenia or rheumatic heart disease (RHD). While the schizophrenia group reported more alienation and less stigma resistance than the RHD group, both groups demonstrated increased stigma resistance over time, after participating in the workshops. Hearing from others living with and managing the same illness normalised participants’ own experiences and encouraged them. Within the SAX study, a short rating scale and qualitative feedback methods were used to evaluate a Mental Health Literacy Day targeting mental health stigma. Information talks about (i) the symptoms of schizophrenia and treatment options and (ii) the illness experiences of a patient in recovery were rated as the most helpful on the day. Audience members reported that these talks challenged negative perceptions about severe mental illness. Three important learnings emerged from these evaluations: firstly, integration of evaluation strategies at the research study planning phase is likely to promote more effective community engagement. Secondly, a combination of quantitative and qualitative methods that draw on simple descriptive statistics and thematic analysis can provide nuanced perspectives about the value of community engagement. Thirdly, such evidence is necessary in establishing and promoting the science of community engagement in genomics research and health research more broadly.
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  • Date Issued: 2021

Industry 4.0 and Skills Deficiencies in the HRM Function: Case Study of the HRM Department of a selected organisation in Cape Town

  • Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
  • Date: 2021
  • Subjects: Personel Management Industry 4.0 Article
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/11260/8095 , vital:61395 , xlink:href="https://www.abacademies.org/articles/industry-40-and-skills-deficiencies-in-the-hrm-function-case-study-of-the-hrm-department-of-a-selected-organization-in-cape-town-10664.html"
  • 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

Interaction of silver nanoparticles with catechol O-methyltransferase: Spectroscopic and simulation analyses

  • Authors: Usman, Aminu , Lobb, Kevin A , Pletschke, Brett I , Whiteley, Christopher G , Wilhelmi, Brendan S
  • Date: 2021
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/451095 , vital:75018 , xlink:href=" https://doi.org/10.1016/j.bbrep.2021.101013"
  • Description: Catechol O-methyltransferase, an enzyme involved in the metabolism of catechol containing compounds, catalyzes the transfer of a methyl group between S-adenosylmethionine and the hydroxyl groups of the catechol. Furthermore it is considered a potential drug target for Parkinson’s disease as it metabolizes the drug levodopa. Consequently inhibitors of the enzyme would increase levels of levodopa. In this study, absorption, fluorescence and infrared spectroscopy as well as computational simulation studies investigated human soluble catechol Omethyltransferase interaction with silver nanoparticles. The nanoparticles form a corona with the enzyme and quenches the fluorescence of Trp143. This amino acid maintains the correct structural orientation for the catechol ring during catalysis through a static mechanism supported by a non-fluorescent fluorophore–nanoparticle complex. The enzyme has one binding site for AgNPs in a thermodynamically spontaneous binding driven by electrostatic interactions as confirmed by negative ΔG and ΔH and positive ΔS values. Fourier transform infrared spectroscopy within the amide I region of the enzyme indicated that the interaction causes relaxation of its β− structures, while simulation studies indicated the involvement of six polar amino acids. These findings suggest AgNPs influence the catalytic activity of catechol O-methyltransferase, and therefore have potential in controlling the activity of the enzyme.
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  • Date Issued: 2021
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