Rhodes University

Rhodes Repository (SEALS)
Not a member yet
    14013 research outputs found

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

    Get PDF
    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

    The prevalence, uses and cultural assimilation of shrub and tree invasive alien plants in a biodiversity hotspot along the Wild Coast, South Africa

    Get PDF
    Invasive alien plant species (IAPS) frequently offer both ecosystem services and disservices to rural communities with high livelihood dependency on local landscapes. However, biocultural relationships with IAPS may go deeper than just provisioning uses, as they may be assimilated into local belief systems manifest in them becoming embedded in cultural constructions such as naming, stories, songs and ceremonies. It is likely that IAPS that are culturally assimilated will represent a greater conflict of interest in the face of proposed controls of IAPS in biodiversity hotspots where conservation priorities are frequently deemed paramount by external agencies. Using a mixed-methods approach we undertook roadside surveys of 17 selected IAPS along the 250 km Wild Coast section of the Maputaland-Pondoland-Albany biodiversity hotspot, accompanied by questionnaire interviews with 48 local people. The mean number of IAPS per site was four, ranging from zero (only one site) to ten, and local inhabitants deemed the abundance of all but one of the species to be increasing. All species had been in the region for decades, had a vernacular name, and all but one had direct consumptive uses. Species with multiple uses were more widely recognised. However, there was only marginal incorporation of the IAPS into stories, songs and ceremonies, although medicinal uses of some IAPS were for cultural/spiritual needs rather than physical ailments per se. These results show that despite widespread use, there was as yet relatively limited cultural assimilation of the IAPS in the Wild Coast region

    The potential of social learning to upscale the Community Based Water Quality Management (CBWQM) process: A case study of the Mpophomeni and Baynespruit Enviro Champs project

    Get PDF
    Water is an essential component of human survival, with a wide variety of uses such as washing, cooking, drinking and growing food. Covering approximately 70% of the Earth’s surface, water is necessary for all human survival, and is a source of life for plants and animals. Only 0.036% of freshwater can be accessed and utilised by humans, which is not enough to support the rapidly growing population and economic development. This water is further exhausted by pollution caused by sewage leaks, littering, agricultural runoff and industry discharge which deteriorate water quality significantly. To exacerbate these water issues, the major issue of water accessibility is not directly linked to quantity but has been primarily attributed to poor water governance, at a global and local level (in South Africa). Poorly maintained water infrastructure and inadequate cooperative governance have resulted in the establishment of many Community Based Water Quality Management (CBWQM) projects in South Africa, to respond to water quality monitoring and management challenges. The aim of this study was firstly, to investigate how social learning was occurring within two CBWQM Communities of Practice (CoPs) located in KwaZulu-Natal, Pietermaritzburg, namely, the Baynespruit and the Mpophomeni Enviro Champs project (Case Study 1 and 2 respectively), and the potential of social learning to upscale CBWQM. Additionally, it sought to identify the type of support required for the scaling of social learning outcomes in CBWQM communities of practice, along two potential scaling pathways that were identified in a national study on scaling of CBWQM: Scaling Pathway 1(Policy engagement and support) and Scaling Pathway 2 (Capacity building). The research was undertaken as a qualitative case study approach, with data collected through semi-structured interviews, document, and questionnaire analysis to investigate social learning within the two selected case studies. The data was coded and indexed using a thematic analysis technique and an analytical framework as a tool to investigate how social learning was occurring in both case studies and explore the potential required to upscale it. The study found that there is an existing gap between policy and practice with regard to CBWQM support by government structures. Despite South African water policy advocating for public participation in water resource management, there has been limited support from government to support and resource CBWQM projects over a long period of time. To upscale the practice of CBWQM, the study found that capacity building and learning needs to be improved and better supported practically through models such as the 5Ts of learning, and through supporting CBWQM participants’ learning journey to establish learning pathways for them.Thesis (MEd) -- Faculty of Education, Education, 202

    Social innovation that connects people to coasts in the Anthropocene

    Get PDF
    Post-industrial society is driving global environmental change, which is a challenge for all generations, current and future. The Anthropocene is the geological epoch in which humans dominate and it is rooted in the past, present, and future. Future sustainability is building on the momentum of the fundamental importance of studying human dynamics and governance of coupled social and ecological systems. In the Anthropocene, social innovation may play a critical role in achieving new pathways to sustainability. This conventional narrative review uses a qualitative analysis anchored in the Grounded Theory Method and a systematic collection and analysis of papers to identify broad types of social innovations. Scientific journal articles published since 2018 were prioritised for inclusion. The six types of social innovation proposed are (a) authentic engagement; (b) artful and engaging communication; (c) urging and compelling change; (d) governance for social-ecological systems; (e) anticipation in governance; and (f) lived experiences and values. The six innovations proposed in this paper can be embedded within, and form part of, social action using a science–society compact for the sustainable development of coasts in the Anthropocene

    Quinolone-Pyrazinamide Derivatives: synthesis, characterisation, in silico ADME analysis and in vitro biological evaluation against Mycobacterium tuberculosis

    Get PDF
    Tuberculosis is one of the leading causes of death worldwide caused by an infectious species, Mycobacterium tuberculosis (Mtb). Some of the factors that contribute to the prevalence of this disease include the complexity of diagnosis, prolonged period of therapy, side effects associated with current TB drugs, the prevalence of resistance against the current treatment options and a high incidence of co-infection with HIV/AIDS. Thus, there is a need for new alternative drugs to provide safer and shorter treatment therapy options that are not susceptible to the development of drug resistance. In this project, we focus our attention on the quinolone pharmacophore. Quinolones are currently used as alternative options in the treatment of resistant strains of Mtb. Previous work pertaining to quinolone-isoniazid hybrid compounds showed promising in vitro activity against the H37Rv strain of Mtb and served as the inspiration to pursue this project. The journey commenced with the synthesis of quinolone-pyrazinamide hybrid compounds (Figure 3.1). These compounds were synthesised, through the attachment of the quinolone and the pyrazinamide entity through a hydrazine linker. The synthesised compounds were purified, and their structural identity confirmed using common spectroscopic techniques including 1H and 13C NMR, infra-red (IR) and mass spectrometry. In vitro biological assays were performed by testing for the activity against the H37RvMA strain of Mtb. The bioassays were performed in triplicates to ensure the accuracy of the results. Moxifloxacin and isoniazid were tested as control compounds. Finally, the resultant compounds were profiled in silico for physicochemical and ADMET properties using open access software SwissADME. All the synthesised compounds 3.8a-f showed no activity against H37RvMA. In most cases, the resulting compounds showed minimal to no activity (MICs ≥ 57.3 μM) in all three media. During the in vitro studies, the compounds showed significant precipitation in the media over time suggesting poor aqueous solubility. The SwissADME analysis of these compounds indicated poor solubility in aqueous media, which is likely linked to their molecular size and complexity. Despite poor aqueous solubility, compounds 3.8a-f showed acceptable physicochemical properties and ADME parameters. No PAINs (Pan-assay interference compounds) were observed. Minimal to no interaction with CYP enzymes were predicted. Most of the compounds were compatible with the Lipinski’s rules of five.Thesis (MSc) -- Faculty of Science, Chemistry, 202

    Combination of photodynamic antimicrobial chemotherapy and ciprofloxacin to combat S. aureus and E. coli resistant biofilms

    Get PDF
    Photodynamic antimicrobial chemotherapy (PACT) coupled with an antibiotic, ciprofloxacin (CIP), was investigated using two indium metallated cationic photosensitizers, a porphyrin (1) and a phthalocyanine (2). Applying PACT followed by the antibiotic treatment led to a remarkable reduction in the biofilm cell survival of two antibiotic-resistant bacterial strains, S. aureus (Gram-positive) and E. coli (Gram-nenative). Treating both bacteria strains with PACT alone showed no significant activity at 32 µM with 15 min irradiation, while CIP alone exhibited a minimum biofilm inhibition concentration (MBIC) at 4 and 8 µg/mL on S. aureus and E. coli, respectively following 24 h incubation. The combined treatment resulted in the complete eradication of the matured biofilms with high log10 reduction values of 7.05 and 7.20 on S. aureus and E. coli, respectively, at low concentrations. It was found that 15 min PACT irradiation of 8 µM of complexes (1 and 2) combined with 2 µg/mL of CIP have a 100% reduction of the resistant S. aureus biofilms. Whereas the total killing of E. coli was obtained when combining 8 µM of complex 1 and 16 µM of complex 2 both combined with 4 µg/mL of CIP

    Social Learning and Regenerative Sustainability: Unlocking value created in sustainability projects in higher education

    Get PDF
    This qualitative study considers two bodies of theory, regenerative sustainability and social learning theory, within a tertiary education context. Universities offer unique opportunities, across both the formal and informal curriculum, that engage with the two-fold socioeconomic and environmental crises. The study explores both the promise of unlocking value in an ex-linear economy; and the healing and regenerative benefits in moving toward greener practices. Through an embedded case study at Rhodes University, in the Eastern Cape of South Africa, this research explores the value that is being unlocked in campus-based sustainability projects, when considered through a social learning lens (Lave and Wenger, 1991). Invitations to participate in this study were extended to project-leads of sustainability initiatives originating from Rhodes University campus. Six projects, which have been active on campus in recent years, were selected and, through semi-structured interviews, the insights of 12 participants were captured and analysed using the associated Value Creation Framework (VCF) developed by Wenger, Trayner and De Laat (Wenger, Trayner, de Laat, 2011) and later Wenger-Trayner and Wenger Trayner (2014, 2015, 2020). The VCF consists of value cycles that interconnect dynamically, including Orientating, Strategic, Enabling, Immediate, Potential, Applied, Realised and Reframed or Transformative value cycles. The study identified instances of all these value cycles, within and across the six embedded case studies (project). Drawing on social learning theorists the analysis further focused on instances of collaboration, agency and boundary crossing. Additional themes that emerged across the majority of the embedded study projects, were a convergence of socio and eco; a whole-systems perspective shared by project leads; the importance of the social commons; language as an enabler; and problem solving for system change. A recommendation is proposed to further unlock the unbounded value created through such projects by reframing the informal curriculum opportunities offered on university campuses as social learning spaces where students can practice agency. To do so, would require formalizing various forms of system support, thus facilitating expanded learning in regenerative sustainability activities, for the common social and planetary good.Thesis (MEd) -- Faculty of Education, Education, 202

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

    Get PDF
    Sustainability-focused research networks and communities of practice have emerged as a key response and strategy to build capacity and knowledge to support transformation towards more sustainable, just and equitable futures. This paper synthesises insights from the development of a community of practice on social-ecological systems (SES) research in southern Africa over the past decade, linked to the international Programme on Ecosystem Change and Society (PECS). This community consists of a network of researchers who carry out place-based SES research in the southern African region. They interact through various cross-cutting working groups and also host a variety of public colloquia and student and practitioner training events. Known as the Southern African Program on Ecosystem Change and Society (SAPECS), its core objectives are to: (1) derive new approaches and empirical insights on SES dynamics in the southern African context; (2) have a tangible impact by mainstreaming knowledge into policy and practice; and (3) grow the community of practice engaged in SES research and governance, including researchers, students and practitioners. This paper reflects on experiences in building the SAPECS community, with the aim of supporting the development of similar networks elsewhere in the world, particularly in the Global South

    The in-vitro proliferation-suppression of MCF-7 and HeLa cell lines mediated by differently substituted ionic phthalocyanines in sonodynamic therapy supplemented-photodynamic therapy

    Get PDF
    This work focuses on the study of the effects of the ultrasonic frequency (MHz) and power (W.cm−2) on the stability, reactive oxygen species yields and cytotoxicity activities of differently substituted ionic phthalocyanines (Pcs) in sonodynamic therapy (SDT). Four ultrasonic parameters were investigated: Par I (1 MHz: 1 W.cm−2), Par II (1 MHz: 2 W.cm−2), Par III (3 MHz: 1 W.cm−2) and Par IV (3 MHz: 2 W.cm−2). A higher degradation of the Pcs was observed with increasing power at the Par II. Two reactive oxygen species (ROS) were detected in the ultrasound treated Pcs: singlet oxygen and hydroxyl radicals. Due to minimal degradation of most Pcs, Par I was chosen for SDT, photodynamic therapy (PDT), and photo-sonodynamic therapy (PSDT) against Michigan Cancer Foundation-7 and Henrietta Lacks cancer cell lines. PSDT generally showed improved therapeutic efficacies of the Pcs compared to the SDT and PDT mono treatments


    full texts


    metadata records
    Updated in last 30 days.
    Rhodes Repository (SEALS) is based in South Africa
    Access Repository Dashboard
    Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇