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The Southern African Program on Ecosystem Change and Society: an emergent community of practice

- Biggs, Reinette, Reyers, Belinda, Blanchard, Ryan, Clements, Hayley S, Cockburn, Jessica J, Cumming, Graeme S, Cundill, Georgina, de Vos, Alta, Dziba, Luthando E, Esler, Karen J, Fabricius, Christo, Hamann, Maike, Henriksson, Rebecka, Kotschy, Karen, Lindborg, Regina, Luvuno, Linda, Masterson, Vanessa A, Nel, Jeanne L, O'Farrell, Patrick, Palmer, Carolyn G, Pereira, Laura, Pollard, Sharon, Preiser, Rika, Roux, Dirk J, Scholes, Robert J, Selomane, Odirlwe, Shackleton, Charlie M, Shackleton, Sheona, Sitas, Nadia, Slingsby, Jasper A, Spierenburg, Marja, Tengö, Maria

The use of a Subjective wellbeing scale as predictor of adherence to neuroleptic treatment to determine poor prognostic factor in African population with Schizophrenia

- Boshe, J J, Stein, Dan J, Campbell, Megan M

  • Authors: Boshe, J J , Stein, Dan J , Campbell, Megan M
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/450766 , vital:74980 , xlink:href="10.1192/j.eurpsy.2023.384"
  • Description: Objectives: To investigate and identify demographic and clinical predic-tors of subjective well-being in a sample of Xhosa people with schizo-phrenia on neuroleptic treatment. Methods: As a part of a large genetic study, 244 study participants with a confirmed diagnosis of schizophre-nia completed the translated SWN-K 20 scale. Internal consistency analysis was performed, and convergent analysis and exploratory analysis were conducted using Principal Component Analysis (PCA). Linear regression methods were used to determine predictors of SWBN in the sample population.
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  • Date Issued: 2023

Transboundary Fisheries Management in Kavango–Zambezi Transfrontier Conservation Area (KAZA-TFCA): Prospects and Dilemmas

- Imbwae, Imikendu, Aswani, Shankar, Sauer, Warwick H H, Hay, Clinton J

  • Authors: Imbwae, Imikendu , Aswani, Shankar , Sauer, Warwick H H , Hay, Clinton J
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/391433 , vital:68651 , xlink:href="https://doi.org/10.3390/su15054406"
  • Description: Inland fisheries in the Kavango–Zambezi Transfrontier Conservation Area (KAZA-TFCA) offer food security to the riverine communities across the region. They also contribute towards the attainment of the United Nations’ Sustainable Development Goals 1 and 15, which aim to alleviate poverty and maintain biodiversity conservation. Despite this significant role, the fisheries have suffered severe declines in the previous decades due to multiple factors, such as overfishing and poor legislation. Furthermore, climate change is exerting pressure by altering the ecology and productivity of the river systems. The unprecedented challenges of the COVID-19 pandemic have further constrained management efforts. Attempts to address these challenges have pointed towards transboundary fisheries management as a silver bullet in moving towards sustainable fisheries management. However, the implementation of this strategy in the region has encountered numerous roadblocks, thereby subjecting the river ecosystem to a wider environmental threat, with dire consequences on livelihoods. This paper reviews existing management and governance structures together with key informant interviews to elicit primary and secondary data essential for management at the regional level. The study identifies conflicting regulations, and inadequate policies and institutions across the region as major bottlenecks affecting the successful implementation of transboundary fisheries management. Finally, the paper offers some suggestions for the improvement of fisheries management in the region.
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  • Date Issued: 2023

TVET SI: Evaluating Boundary Crossing Social Learning in Vocational Education and Training: A value creation approach

- Lotz-Sisitka, Heila, Sisitka, Lawrence, Chakona, Gamuchirai, Matiwane, Mandilive L, Matambo, Chamu

  • Authors: Lotz-Sisitka, Heila , Sisitka, Lawrence , Chakona, Gamuchirai , Matiwane, Mandilive L , Matambo, Chamu
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/389925 , vital:68495 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/238540"
  • Description: This article focuses on the development and application of an evaluation model and approach for evaluating boundary crossing social learning in a Vocational Education and Training (VET) learning network in South Africa, with an emphasis on a Training of Trainers (ToT) course that helped to catalyse and strengthen this learning network via two iterations of the course over an eight-year period. The article shares how we adapted the value creation framework (VCF) of Wenger, Traynor and De Laat (2011; Wenger and Wenger-Traynor, 2020) in the evaluation of a VET Training of Trainers (ToT) programme and learning network that focussed on the uptake and circulation of rainwater harvesting and conservation (RWHandC) knowledge in a particular formal and informal VET context in the Eastern Cape, South Africa, where smallholder farmers were struggling to find water for producing food. The evaluated ToT course was catalytic in establishing a boundary crossing social learning network approach in a VET context that linked formal and informal VET (Lotz-Sisitka et al., 2016; Lotz-Sisitka et al., 2022; Pesanayi, 2019); hence we found it important to develop adequate tools for its evaluation. The focus of this article is to share how we developed an evaluation approach to this work. We share insights on the indicators developed for diff erent types of value created, and also insights gained into the use of this evaluation approach in a boundary crossing VET social learning project that took a ToT course as focus. In short, evaluation findings show that the boundary crossing ToT course off ers strong immediate, potential and applied value that can lead to realised and reframed value, especially if supported by ongoing learning network activities that follow the initial engagement in the boundary crossing ToT course. Th is leads, over time, to transformative value which is important in achieving the overall objective of such social learning, namely making knowledge more co-engaging, accessible and useful in the context where improved food security via better use of rainwater harvesting and conservation amongst smallholder farmers and household food producers is a necessary form of sustainable development. Orientation value, and enabling value were found to be vital for the emergence of other kinds of value. The evaluation model also allows for the lifting out of strategic value which points to wider uptake potential. All this creates the possibility for indicator development that can help inform iterative development of boundary crossing VET courses used to stimulate the co-construction of learning networks and ongoing social learning for sustainable development.
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  • Date Issued: 2023

Understanding foraging practices in Lagos metropolis to redesign urban greenspaces in support of human-nature interactions

- Adeyemi, Opeyemi, Shackleton, Charlie M

  • Authors: Adeyemi, Opeyemi , Shackleton, Charlie M
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/401353 , vital:69728 , xlink:href="https://doi.org/10.1016/j.ufug.2022.127805"
  • Description: Enhancing knowledge of urban foraging across different urban landscapes is an urgent matter given that about two-thirds of the world’s population is projected to live in urban areas by 2050, whilst 50 % of Africa’s population is expected to live in cities by 2030. This study was conducted in Lagos metropolis which is the economic hub of Africa’s most populous country. Data was collected using an in-person, semi-structured questionnaire from 347 persons who were 18 years or older to identify foragers and non-foragers, their sociodemographic profiles, and their foraging practices. Results revealed that about two out of three persons sampled forage to some degree. The collection happened more in domestic gardens (34 %) and streets (27 %) than in other foraging sites (such as unused lands, institutional grounds and lakes and riparian fringes). A total of 35 species were reportedly foraged within the metropolis, mostly for food (71 %) and medicine (26 %). Mango (Mangifera indica), pawpaw (Carica papaya), tropical almond (Terminalia catappa), fish (various species), bitter leaf (Vernonia amygdalina) and spinach (Spinacia oleracea) were the most gathered species. The distance travelled to foraging wild species ranged from 5 m to 25 km. The primary motivation for foraging was the acquisition of fresh and natural materials. However, some felt that foraging was a stressful activity. The unavailability of foraging sites and species was the major constraint to foraging in this megacity. Hence, efforts to increase the edible components of public green spaces and to provide free access could potentially allow more people to forage and make current foraging more secure. We suggest that making provisions for foraging in urban planning goals could contribute to the sustainable development of cities in Africa and elsewhere.
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  • Date Issued: 2023

Using Facebook user photos to quantify surface water dependency in Southern African arid-zone bird species

- Dixon, Elizabeth A, Smit, Ben

  • Authors: Dixon, Elizabeth A , Smit, Ben
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/441668 , vital:73905 , https://doi.org/10.1080/01584197.2023.2182223
  • Description: Birds need to maintain their hydration by either gaining water from their food or by drinking surface water. Many arid-zone birds do not need to consume surface water to maintain body condition. Conservationists need to better understand avian use of surface water sources to inform management plans in a warming world. In this study, we explored the use of Facebook’s image search as a tool to predict interspecific variations in avian surface water use. There was a significant correlation between the proportion of Facebook photographs of each species associated with surface water, and surface water use indices for these species based on published field studies. These findings suggest that Facebook may be a useful source of data for determining the dependence of bird species on surface water. Future research could address the potential for Facebook and other social media platforms for answering a range of ecological questions relating to avian water dependency.
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  • Date Issued: 2023

Wing-moult and seasonal occurrence of sunbirds (Nectariniidae) captured at four sites in the Eastern Cape, South Africa

- Bonnevie, Bo T, Craig, Adrian J F K, Hulley, Patrick E, Schultz, Albert, Tree, Anthony J

  • Authors: Bonnevie, Bo T , Craig, Adrian J F K , Hulley, Patrick E , Schultz, Albert , Tree, Anthony J
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/449607 , vital:74833 , https://doi.org/10.2989/00306525.2022.2075482
  • Description: Ringing activity in the Eastern Cape province, South Africa, spanned 30 years, with three sites active concurrently over a 14-year period, and three sites over a 6-year period. In total, in the course of 714 ringing days, in all months, we handled 1 207 Amethyst Sunbirds, 708 Southern Double-collared Sunbirds, 707 Greater Double-collared Sunbirds, 381 Grey Sunbirds, 121 Malachite Sunbirds and 140 Collared Sunbirds. Although individuals of all six species were recaptured more than five years after ringing, and despite evidence of the seasonal passage of sunbirds at two sites near the Indian Ocean coast, no birds were recaptured away from the original ringing site.
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  • Date Issued: 2023

Women farmers leading and co-learning in an agroecology movement at the intersections of gender and climate

- Chanyau, Ludwig, Rosenberg, Eureta

  • Authors: Chanyau, Ludwig , Rosenberg, Eureta
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/373873 , vital:66730 , xlink:href="https://doi.org/10.1080/10130950.2023.2239313"
  • Description: This study, carried out in the Eastern Cape Province of South Africa, was particularly interested in women farmers’ access to social learning spaces for expanding their knowledge about farming in the context of climate change. Small-scale women and peasant farmers face historical intersectional inequalities as a result of the colonial and apartheid past which has continued to disadvantage women in the present through exclusion, limited or no access to finance, insecure or no land tenure, little bargaining power and unequal access to water. The gender prejudices and unequal access to resources experienced by women is brought into sharp relief by climate change. The article provides a case study of an agroecology movement led by women farmers that promotes climate-appropriate, low-cost farming practices using community and home gardens. The practices are tried out and further developed by women farmers themselves, relying on agroecology-informed extension services, open dialogue and the support of communities of practice. Unlike traditional top-down approaches to farmer learning common in public extension services, extension officers in the movement participate in creating conditions for co-learning and co-construction of new knowledge − that is, social learning − thus responding directly to their needs as farmers. The lead researcher joined in and observed farming and learning activities following an ethnographic approach. Farmers and other movement members were engaged in semi-structured interviews which explored the value derived from social learning (Wenger-Trayner and Wenger-Trayner Citation2020). The article concludes that the movement is responding to many of the intersectional challenges that women farmers in the Eastern Cape face. Further, its social learning approach holds potential for expanding women farmers’ ability to provide for themselves and their communities and inform their climate change adaptation.
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  • Date Issued: 2023

A Change Project story: learning and caring for South Africa’s rivers

- Chetty, Preven

  • Authors: Chetty, Preven
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/391060 , vital:68613 , xlink:href="https://eeasa.org.za/wp-content/uploads/2023/02/Final-EEASA-Bulletin-20212022-Final.pdf"
  • Description: Water quality and scarcity is a major concern in Southern Africa and globally especially as the threat of climate change looms even closer. The current drought in South Africa and worsening rainfall has exposed the brittle nature of this country’s resilience to water shortages. Compounded to this is the fact that most rivers in South Africa are not adequately cared for and are under tremendous strain. Everyone who depends on these rivers whether directly or indirectly will soon be entering a new era where water will no longer be a ubiquitous commodity.
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  • Date Issued: 2022

A laminated, emergentist view of skills ecosystems

- Ramsarup, Presha, Lotz-Sisitka, Heila, McGrath, Simon

  • Authors: Ramsarup, Presha , Lotz-Sisitka, Heila , McGrath, Simon
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/370074 , vital:66295 , xlink:href="https://doi.org/10.1080/14767430.2022.2145768"
  • Description: In this paper we present a model of vocational education and training (VET) that can be used to guide decisions relating to VET in Africa today. This model takes the critique of the neoclassical, neoliberal model of VET as its starting point. Guided by Bhaskar's Critical Naturalism, we use immanent critique to consider the adequacy of proposed alternatives to the neoclassical approach, such as: the heterodox approach, which foregrounds explanations based on human capital and political economy; and Hodgson and Spours' social ecosystem model, which addresses some of the limitations of the heterodox account by including, social and ecosystem elements. Finally, we offer a version of the social ecosystem model that, according to our analysis, explains more of the empirical evidence than previous models. Our version of the social ecosystem model differs from earlier versions in terms of its explicit reference to the critical realist ideas of position- practices and emergence.
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  • Date Issued: 2022

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

- Musikavanhu, Brian, Muthusamy, Selvaraj, Zhu, Dongwei, Xue, Zhaoli, Yu, Qian, Chivumba, Choonzo N, Mack, John, Nyokong, Tebello, Wang, Shengjun, Zhao, Long

  • 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

A Sn (iv) porphyrin with mitochondria targeting properties for enhanced photodynamic activity against MCF-7 cells

- Babu, Balaji, Mack, John, Nyokong, Tebello

  • Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
  • Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
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  • Date Issued: 2022

African birds as army ant followers

- Craig, Adrian J F K

  • Authors: Craig, Adrian J F K
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/448772 , vital:74759 , https://doi.org/10.1007/s10336-022-01987-0
  • Description: Ant-following birds have been studied extensively in the Neotropics, but much less information is currently available for the Afrotropics. There are published records of 168 African bird species from 37 families foraging in association with driver ants (Dorylus, sub-family Dorylinae). However, of 52 bird species assessed as regular ant-followers, 38 belong to three families, which are disproportionately represented compared to other large Afrotropical bird families: Muscicapidae (18 spp.), Pycnonotidae (13 spp.) and Turdidae (7 spp.). The extent to which these birds are dependent on ants through their annual cycle is not known. African driver ants forage primarily under shaded, humid conditions by day, and may spend a month or longer underground. Conservation assessments of African forest habitats suggest that both driver ants and ant-following birds may be especially sensitive to the loss of forest cover.
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  • Date Issued: 2022

Age and growth of the Cape knifejaw Oplegnathus conwayi, an endemic South African teleost

- Foster, Ryan M, Childs, Amber-Robyn, Mann, Bruce Q, Potts, Warren M

  • Authors: Foster, Ryan M , Childs, Amber-Robyn , Mann, Bruce Q , Potts, Warren M
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/443128 , vital:74080 , https://doi.org/10.1080/15627020.2022.2035254
  • Description: The South African spearfishery targets a variety of data-deficient species, which are consequently poorly managed. This study aimed to describe the age and growth of one of these species, the Cape knifejaw, Oplegnathus conwayi, which is endemic to the southern and eastern coasts of South Africa. Monthly biological samples were collected through research spearfishing (n = 170) and augmented by recreational spearfishers’ catches (n = 135). The results indicated that the O. conwayi population sex ratio was skewed towards males (1M:0.6F). The length- and age-frequency distributions were similar between sexes. Oplegnathus conwayi is a relatively slow-growing species, with a maximum-recorded age of 27 years. No significant differences were observed between male and female growth, with the overall population growth curve being best described as L(t) = 697.15(1 − e−0.06(t−6.30)). The slow growth observed in this species is characteristic of a species that is vulnerable to overexploitation, and accordingly a precautionary approach to future management is recommended.
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  • Date Issued: 2022

Application of gold and palladium nanoparticles supported on polymelamine microspheres in the oxidation of 1-phenylethanol and some other phenyl substituted alcohols

- Storm, Ené, Maggott, Emile D, Mashazi, Philani N, Nyokong, Tebello, Malgas-Enus, Rehana, Mapolie, Selwyn F

  • Authors: Storm, Ené , Maggott, Emile D , Mashazi, Philani N , Nyokong, Tebello , Malgas-Enus, Rehana , Mapolie, Selwyn F
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/299824 , vital:57858 , xlink:href="https://doi.org/10.1016/j.mcat.2022.112456"
  • Description: Melamine formaldehyde and melamine resorcinol formaldehyde microspheres were decorated with Au and Pd nanoparticles and applied as heterogeneous catalysts in the oxidation of 1-phenylethanol. The catalysts showed similar activities irrespective of the support employed. Moderate conversion activities of 48–50% were achieved when using acetonitrile as solvent; however, when employing water as solvent, the supported catalysts formed a three-phase, emulsion system which facilitated the catalytic conversion of 1-phenylethanol to acetophenone at much higher conversions of around 83%. The oxidant, TBHP, decomposed rapidly in acetonitrile, whilst it remained stable in aqueous solution, leading to the enhanced activities observed when using water as solvent. These systems also proved to be recyclable for up to five cycles, with only slight loss of activity observed; this can be attributed to the physical loss of catalyst during the workup procedure conducted between each cycle.
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  • Date Issued: 2022

Aptamer versus antibody as probes for the impedimetric biosensor for human epidermal growth factor receptor

- Centane, Sixolile, Nyokong, Tebello

  • Authors: Centane, Sixolile , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/229884 , vital:49720 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2022.111764"
  • Description: In the present work, the performance of aptamer and antibody bioreceptors for the detection of the human epidermal growth factor receptor (HER2) cancer biomarker on a glassy carbon electrode is reported. The carboxylic acid group rich graphene quantum dots (GQDs) modified with gold nanoparticles and a porphyrin binuclear framework (CoP-BNF) were used to modify the glassy carbon electrode. The aptamer and antibody were both amine functionalized and attached to GQDs and CoP-BNF through an amide bond. The designed immunosensors and aptasensors in this work were characterized using electrochemical impedance spectroscopy. The aptasensors, compared to the immunosensors gave better limit of detection values. The aptasensor outperforms the immunosensor in terms of its reusability and storability, while the immunosensor could not be regenerated for subsequent experiments. The potential applicability of all sensors in this work was also investigated, by detection of HER2 in spiked human serum with acceptable results.
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  • Date Issued: 2022

Assessing climate risk to support urban forests in a changing climate

- Esperon-Rodriguez, Manuel, Rymer, Paul D, Power, Sally A, Barton, David N, Cariñanos, Paloma, Dobbs, Cynnamon, Eleuterio, Ana A, Escobedo, Francisco J, Hauer, Richard, Hermy, Martin, Jahani, Ali, Onyekwelu, Jonathan C, Östberg, Johan, Pataki, Diane, Randrup, Thomas B, Rasmussen, Tørres, Roman, Lara A, Russo, Alessio, Shackleton, Charlie M, Solfjeld, Ingjerd, van Doorn, Natalie S, Wells, Matthew J, Wiström, Björn, Yan, Pengbo, Yang, Jun, Tjoelker, Mark G

Assessing the electrocatalytic activity of a localized push-pull system in cobalt phthalocyanine/graphene quantum dot hybrids

- Nkhahle, Reitumetse, Nyokong, Tebello

  • Authors: Nkhahle, Reitumetse , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/229909 , vital:49722 , xlink:href="https://doi.org/10.1016/j.matchemphys.2022.125842"
  • Description: In this study, two cobalt phthalocyanines (asymmetric complex 1) and symmetric (complex 2) were synthesized and conjugated to nitrogen-doped graphene quantum dots (NGQDs) through covalent and non-covalent means to create Co phthalocyanine (CoPc)-NGQDs hybrid systems. The CoPcs and conjugates were applied as electrode modifiers on a glassy carbon electrode in the electrochemical sensing of nitrite. Of the CoPcs alone, complex 1 performed better than complex 2 regarding the limits of detection (LoD) recorded (5.74 μM for 1 and 15.1 μM for 2). Regarding the conjugates/nanocomposites, the π-π stacked conjugate derived from complex 2 (2πNGQDs) demonstrated highly favourable electrochemical potential with an LoD value of 0.70 μM. The nanocomposites fashioned from complex 1 were marred by a reduced loading which rendered the conjugates poor electrochemical sensors. These observations however do not disqualify GQDs as complementary nanomaterials to phthalocyanines but rather shed light on seeking alternative routes to increasing the Pc loading in conjugates (more so in π-π stacked conjugates).
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  • Date Issued: 2022

Assessing the Impact of DNS Configuration on Low Bandwidth Networks

- Okuthe, J A, Terzoli, Alfredo

  • Authors: Okuthe, J A , Terzoli, Alfredo
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/430903 , vital:72726 , https://doi.org/10.1007/978-3-031-34896-9_6
  • Description: Domain name system (DNS) is an essential enabler for connecting us-ers and services on the Internet. DNS translates human readable do-main names into IP addresses and precedes client connection to a server via a domain name. DNS service is therefore expected to con-sume network bandwidth even though it offers no direct benefit to the user. Having observed the large component of DNS traffic on the com-munity network local loop in our previous study, we migrated the DNS service from a server on the LAN to the gateway router and reconfig-ured the cache time-to-live. Results from the analysis of network traffic captured from the gateway router interface show a 26% decrease in the downlink bandwidth utilization and 46% decline in the uplink bandwidth utilization. The DNS component of the local loop traffic reduces from 45.28% to 4.11%. On the other hand, the Web component of the local loop traffic increases from 49.42% to 95.49%. Data collected from a mirroring port on the LAN switch indicate a decrease in the DNS portion of the internal traffic from 0.38% to 0.18%. Although the DNS reconfigu-ration helps alleviate network bandwidth constraints and reduces DNS component of the traffic, the Web portion increases. The implementa-tion of effective, efficient and sustainable Web traffic management is therefore required.
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  • Date Issued: 2022

Asymmetrical zinc (II) phthalocyanines conjugated to metal tungstate nanoparticles for photoinactivation of Staphylococcus aureus

- Mgidlana, Sithi, Managa, Muthumuni, Nyokong, Tebello

  • Authors: Mgidlana, Sithi , Managa, Muthumuni , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/295718 , vital:57372 , xlink:href="https://doi.org/10.1080/00958972.2022.2090837"
  • Description: In this study, we report for the first time on the photodynamic antimicrobial chemotherapy (PACT) of asymmetrical zinc(II) phthalocyanines and their conjugates with nickel tungstate (NiWO4), cobalt tungstate (CoWO4) and bismuth tungstate (Bi2WO6) nanoparticles. CoWO4, NiWO4 and Bi2WO6 were capped with glutathione and covalently linked to three asymmetrical zinc(II) phthalocyanines for PACT. The plate count method was used to investigate the effect of covalently linking asymmetrical zinc(II) phthalocyanines to nanoparticles under light (for PACT against Staphylococcus aureus) and in the dark. Both Pc complexes and the conjugates indicated minimum dark-toxicity. The conjugates showed greater antimicrobial activity against a gram-positive and drug resistant bacteria, Staphylococcus aureus, than Pc complexes alone.
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  • Date Issued: 2022
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