Photodegradation of tetracycline by asymmetrical zinc (II) phthalocyanines conjugated to cobalt tungstate nanoparticles
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300233 , vital:57908 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132938"
- Description: This work focused on syntheses of novel asymmetrically tetra substituted Zn phthalocyanines (ZnPc) each containing a single carboxyl group, with the other substituents bearing alkynyl (complex 1) and fluorine containing groups (complexes 2 and 3). The complexes were conjugated to cobalt tungstate nanoparticles and employed as efficient photocatalysts for degradation of tetracycline in water. ZnPc complexes and their conjugates showed good photophysical and photochemical properties behaviour with complex 1 giving higher triplet and singlet oxygen quantum yields compared to 2 and 3. Complex 1 showed higher activity towards the photodegradation of tetracycline compared to complexes 2 and 3, with higher kobs and initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model.
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- Date Issued: 2022
Photodynamic activity of novel cationic porphyrins conjugated to graphene quantum dots against Staphylococcus aureus
- Authors: Magaela, Bridged N , Makola, Lekgowa C , Managa, Muthumuni , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295797 , vital:57379 , xlink:href="https://doi.org/10.1142/S1088424622500316"
- Description: Novel 5-(pyridyl)-10-15-20-tris(4-bromophenyl) porphyrin (complex 1), indium metal derivative (complex 2), and quaternized derivative (complex 3) were synthesized and conjugated to graphene quantum dots (GQDs). The conjugation of the porphyrins to GQDs was through ππ-ππ stacking. Herein, the ππ-ππ stacking approach was used to avoid covalent conjugation which might compromise the intrinsic chemical and physical properties. The photodynamic activities of the proposed nanomaterials were assessed towards Staphylococcus aureus cell obliteration. The photophysical properties of the prepared complexes were also studied prior to the application. Moreover, a decrease in fluorescence lifetimes was observed upon metalation of complex 1. As anticipated, singlet oxygen quantum yield (ΦΔ)ΦΔ) increased notably upon heavy metal (indium) insertion and upon composite formation. Antimicrobial photodynamic therapy comparative studies were done on quaternized and unquaternized indium porphyrins conjugated to GQDs. Complex 3-GQDs exhibited the highest antibacterial activities compared to other complexes, and this was attributed to the high ΦΔΦΔ which plays an imperative role in photodynamic therapy applications.
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- Date Issued: 2022
Photodynamic therapy activity of 5, 10, 15-tris (5-bromo-2-thienyl), 20 (phenylcarboxy) porphyrin conjugated to graphene quantum dot against MCF-7 breast cancer cells
- Authors: Makola, Lekgowa Collen , Nwahahra, Nnamdi , Managa, Muthumuni , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300244 , vital:57909 , xlink:href="https://doi.org/10.1080/00958972.2022.2087515"
- Description: A novel 5,10,15-tris(5-bromo-2-thienyl),20(phenylcarboxy)porphyrin and its gallium derivative have been synthesized and fully characterized by various spectroscopic techniques and their respective photophysical and photochemical properties, such as the singlet oxygen quantum yield (ΦΔ), fluorescence quantum yield (ΦF) and triplet lifetime (τT) were determined. The complexes were conjugated to PEI_GQDs resulting is stable conjugates, owing to strong π–π stacking interaction between the PEI_GQDs and the porphyrins. PDT studies were carried out on these nanoconjugates and results obtained indicated they are suitable candidates for further in-depth PDT studies.
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- Date Issued: 2022
Photodynamic therapy characteristics of phthalocyanines in the presence of boron doped detonation nanodiamonds
- Authors: Matshitse, Refilwe , Nwaji, Njemuwa , Managa, Muthimuni , Chen, Zhi-Long , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229921 , vital:49723 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102705"
- Description: The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone.
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- Date Issued: 2022
Phthalocyanine based fabricated exfoliated graphite photoanode for electrodegradation of 4-acetamidophenol under visible light irradiation
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295809 , vital:57380 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114115"
- Description: In this study exfoliated graphite (EG) was prepared from natural graphite flakes and incorporated with zinc phthalocyanine for fabrication of photoanode. The electron transfer capabilities of fabricated photoanode were examined by using cyclic voltammetry, electrochemical impedance spectroscopy and scanning electrochemical microscopy. Electrophotocatalytic degradation of 4-acetamidophenol in 0.1 M Na2SO4 electrolyte was performed. The photoanode with zinc phthalocyanine (EG-ZnPc) displayed better degradation compared to when only exfoliated graphite was used (EG). Furthermore, electrophotocatalytic degradation gave better performance (removal efficiency of 47.76%) than when individual electrochemical degradation and photodegradation techniques were used.
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- Date Issued: 2022
Plagiarism and the commodification of knowledge
- Authors: McKenna, Sioux
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426967 , vital:72404 , xlink:href="https://doi.org/10.1007/s10734-022-00926-5"
- Description: Universities have put in place various policies and punishments to manage plagiarism and it is an issue of signifcant interest. This article looks at how plagiarism is discussed in the 55 Higher Education articles between 1982 and June 2022 that make some reference to the term. Many of the articles focused on a police-catch-punish approach and imbued a strong moral charge to the issue. In contrast to such articles were those that presented citation as a complex academic practice that needs to be engaged with educationally. Our understandings of and responses to plagiarism emerge from a number of causal mechanisms but I argue that a key mechanism is the commodifcation of knowledge. Where knowledge is a product to be packaged, bought, and sold, then ownership and attribution become more important than engagement and personal meaning making. Instead of our obsession with a police-catch-punish approach to plagiarism, at a more micro-level, we should be inducting students into the many roles citations serve, and at a macro-level, we should be engaging in considerations of the purposes of a higher education and how we might better enable students to enjoy a transformative relationship to knowledge.
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- Date Issued: 2022
Planetary Urgency, Researcher Reflexivity and ESE Research: Questions Arising from an Initial Exploration of Goethean-inspired Phenomenology
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437541 , vital:73392 , ISBN
- Description: Many of the theoretical and methodological frameworks that are currently influential in Environment and Sustainability Education (ESE) research in South Africa foreground interventionist research, activism, causal explanation, critique, social-ecological transformation and decoloniality. These frameworks guide ESE researchers to design, implement and report on research in particular ways, hence influencing how social-ecological phenomena, learning and social change are understood and enacted. In this essay, I present some exploratory perspectives on the relevance and potential contribution of phenomenological approaches to ESE research, especially Goethean inspired observation.
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- Date Issued: 2022
Postgraduate education in a globalised world
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434469 , vital:73066 , ISBN 9781991201225 , https://www.google.co.za/books/edition/The_Global_Scholar/KvQ3EAAAQBAJ?hl=enandgbpv=0
- Description: Interest in postgraduate education and the supervision of postgraduate research has developed in recent years, largely as a result of the impact of the so-called ‘knowledge economy’. South Africa’s National Plan 20301 draws on globalised discourses in holding that increases in the number of graduates, particularly at doctoral level, will contribute to economic prosperity because of the potential of postgraduate education to contribute to the processes of reinvention that drive the economic system itself. Even a brief glance at the mission and vision statements of a small sample of universities shows how this idea has been taken up within the higher education sector. In the context of high levels of unemployment, the idea that a postgraduate degree can lead to better work prospects also means that students who might never have considered doing a postgraduate degree previously, have now come forward to study at this level. All this then means that academics are being called upon to take on heavier supervision loads with a diverse array of students.
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- Date Issued: 2022
Principles of Computer Architecture
- Authors: Machanick, Philip
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439184 , vital:73553 , https://homes.cs.ru.ac.za/philip/Courses/CSHonsArch/HonsArchNotes2022.pdf
- Description: Last week, Control Data ... announced the 6600 system. I understand that in the laboratory developing the system there are only 34 people including the janitor. Of these, 14 are engineers and 4 are programmers... Contrasting this modest effort with our vast development activities, I fail to understand why we have lost our industry leadership position by letting someone else offer the world’s most powerful computer – Thomas Watson Jr., IBM CEO, August 1963 It seems like Mr. Watson has answered his own question – Seymour Cray
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- Date Issued: 2022
Promotion of Catalytic Oxygen Reduction Reactions
- Authors: Wei, Yuqin , Zhao, Long , Yuan, Rui , Xue, Zhaoli , Mack, John , Chivumba, Choonzo , Nyokong, Tebello , Zhang, Jianming
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300347 , vital:57919 , xlink:href="https://doi.org/10.1021/acs.inorgchem.2c01591"
- Description: Three ABAB-type cobalt meso-tetraarylporphyrins with fluorine (F-CoPor), acetic acid (AC-CoPor), and cyanoacetic acid (CN-CoPor) groups at the para-positions of phenyl rings at the 10,20-positions are synthesized and evaluated as catalysts for oxygen reduction reactions (ORRs). In density functional theory calculations, the frontier molecular orbitals of these complexes were found to be stabilized relative to model complexes with electron-withdrawing atoms or moieties on the meso-aryl rings. Electrochemical measurements suggest that electrodes with CN-CoPor (CN-CoPor/C) exhibit the most positive ORR potential values and the highest limiting current density in both acidic and alkali electrolytes, while the F-CoPor/C electrocatalyst exhibits extremely low ORR performance. The electron transfer numbers for the electrocatalysts are more than 3.0, indicating that a mixture of 2- and 4-electron transfer pathways occurs. The results demonstrate that coupling the hydrogen bonding properties and electron-withdrawing abilities through rational design of the substituent at the meso-position is an efficient way to modify the ORR performance.
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- Date Issued: 2022
Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications
- Authors: Ntsimango, Songeziwe , Gandidzanwa, Sendibitiyosi , Joseph, Sinelizwi V , Hosten, Eric C , Randall, Marvin , Edkins, Adrienne L , Khene, Samson M , Mashazi, Philani N , Nyokong, Tebello , Abrahams, Abubak’r , Tshentu, Zenixole R
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300257 , vital:57910 , xlink:href="https://doi.org/10.1002/open.202200037"
- Description: A novel alternative route to access rhenium(V)−phthalocyanine complexes through direct metalation of metal-free phthalocyanines (H2Pcs) with a rhenium(VII) salt in the presence of various two-electron reducing agents is presented. Direct ion metalation of tetraamino- or tetranitrophthalocyanine with perrhenate (ReO4−) in the presence of triphenylphosphine led to oxidative decomposition of the H2Pcs, giving their respective phthalonitriles. Conversely, treatment of H2Pcs with ReO4− employing sodium metabisulfite yielded the desired ReVO−Pc complex. Finally, reaction of H2Pcs with ReO4− and NaBH4 as reducing agent led to the formation of rhenium oxide (RexOy) nanoparticles (NPs). The NP synthesis was optimised, and the RexOy NPs were capped with folic acid (FA) conjugated with tetraaminophthalocyanine (TAPc) to enhance their cancer cell targeting ability. The cytotoxicity profile of the resultant RexOy−TAPc−FA NPs was assessed and found to be greater than 80 % viability in four cell lines, namely, MDA−MB-231, HCC7, HCC1806 and HEK293T. Non-cytotoxic concentrations were determined and employed in cancer cell localization studies. The particle size effect on localization of NPs was also investigated using confocal fluorescence and transmission electron microscopy. The smaller NPs (≈10 nm) were found to exhibit stronger fluorescence properties than the ≈50 nm NPs and exhibited better cell localization ability than the ≈50 nm NPs.
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- Date Issued: 2022
Refining youth sexualities empowerment programmes: The development of the Masizixhobise Toolkit based on a critical sexual and reproductive citizenship framework
- Authors: Macleod, Catriona I , Moore, Sarah-Ann
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434158 , vital:73035 , ISBN 9781003139782 , https://www.taylorfrancis.com/chapters/edit/10.4324/9781003139782-15/refining-youth-sexualities-empowerment-programmes-catriona-ida-macleod-sarah-moore
- Description: Youth sexualities programmes frequently focus on empowering young people in relation to sexual decision-making and interactions. Within these programmes, however, empowerment is mostly equated with the individualised concepts of self-efficacy and agency to the exclusion of interpersonal and social (i.e. collective) components. Resultantly, the social justice aspects of empowerment may be overlooked. Noting this, some researchers have argued for the adoption of a broader, integrative conceptualisation of empowerment. Macleod’s and Vincent’s critical sexual and reproductive citizenship (CSRC) framework provides such a conceptualisation. This framework draws from feminist re-workings of the principles of citizenship and applies these to understandings of CSRC. Based on this framework, key issues for consideration in programmes are: sexual and reproductive citizenship as status and practice; situated agency; differentiated universalism; the interweaving of the private and public; and the politics of recognition, redistribution and reparation. This chapter discusses the development of a programme refinement toolkit based on a CSRC framework, named the Masizixhobise Toolkit; how the elements outlined above were operationalised into questions; an illustrative example; and the partnership formed with a youth empowerment non-governmental organisation in developing the toolkit.
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- Date Issued: 2022
Reflections from early-career researchers on the past, present and future of doctoral education
- Authors: Mason, Shannon , Lévesque, Maude , Meki-Kombe, Charity , Abel, Sophie , Balaban, Corina , Chiappa, Roxana , Grund, Martin , Joubert, Biandri , Kuchumova, Gulfiya , Mantai, Lilia , Main, Joyce , Motshoane, Puleng , Qi, Jing , Steyn, Ronel , Zheng, Gaoming
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434543 , vital:73075 , ISBN 9781800080218 , https://library.oapen.org/bitstream/handle/20.500.12657/58197/1/9781800080188.pdf#page=264
- Description: Early-career researchers (ECRs) played a unique and explicit role in the development of the Hannover Recommendations 2019. We, the ECRs, were the recipients of competitive travel scholarships generously funded by Volkswagen Stiftung, whose support brought us together from across the globe. Attendance at the culminating conference in Germany presented an opportunity for some that would have otherwise been inaccessible without that support. Our role was to work alongside established scholars to design and develop a set of recommendations to provide a foundation for the future of doctoral education internationally. We each participated in different capacities, with some members of the group joining preliminary pre-conference online meetings and contributing to group discussions at the workshop in the days prior to the conference, which also involved the drafting of written reports. Others joined later in the process, participating in the discussions that were a central part of the conference proceedings. During the events we also had informal opportunities to discuss issues related to various aspects of doctoral education. Although we participated in varying degrees and contexts, we each contributed to discussions on the current status and future directions of doctoral education globally.
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- Date Issued: 2022
Reproductive health systems analyses and the reparative reproductive justice approach: a case study of unsafe abortion in Lesotho
- Authors: Macleod, Catriona I , Reynolds, John H
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441288 , vital:73874 , xlink:href="https://doi.org/10.1080/17441692.2021.1887317"
- Description: Health systems analyses are touted as mechanisms through which health policy and planning may be implemented. An example is the WHO health systems approach that connects people (needs, rights, perspectives) with services and technologies (equitable access, quality of care, mix of interventions) and with policies and institutional capacities (laws, regulations, human/physical resources, management and financing). The approach is comprehensive and multi-faceted, which is a strength. We argue, however, that health systems analyses should be supplemented with a focus on reproductive justice. Using the WHO health systems approach as an exemplar, we show how the reparative reproductive justice approach outlined by the first author and colleagues assists with outlining comprehensive remedies to the inequities identified in the systems analysis. We argue for attention to remedies at individual and collective, material and symbolic levels. We illustrate our argument using unsafe abortion, legal abortion services and post-abortion care in Lesotho as a case study. We outline the policies, services and people components of abortion in Lesotho using the WHO systems model, followed by a reparative justice analysis of remedies.
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- Date Issued: 2022
Review of Importance of Weather and Environmental Variables in Agent-Based Arbovirus Models
- Authors: Pascoe, Luba , Clemen, Thomas , Bradshaw, Karen L , Nyambo, Devotha G
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440300 , vital:73764 , xlink:href="https://doi.org/10.3390/ijerph192315578"
- Description: The study sought to review the works of literature on agent-based modeling and the influence of climatic and environmental factors on disease outbreak, transmission, and surveillance. Thus, drawing the influence of environmental variables such as vegetation index, households, mosquito habitats, breeding sites, and climatic variables including precipitation or rainfall, temperature, wind speed, and relative humidity on dengue disease modeling using the agent-based model in an African context and globally was the aim of the study. A search strategy was developed and used to search for relevant articles from four databases, namely, PubMed, Scopus, Research4Life, and Google Scholar. Inclusion criteria were developed, and 20 articles met the criteria and have been included in the review. From the reviewed works of literature, the study observed that climatic and environmental factors may influence the arbovirus disease outbreak, transmission, and surveillance. Thus, there is a call for further research on the area. To benefit from arbovirus modeling, it is crucial to consider the influence of climatic and environmental factors, especially in Africa, where there are limited studies exploring this phenomenon.
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- Date Issued: 2022
Season and environment modulate aquatic invertebrates’ responses to trout and indigenous fishes in three South African mountain streams
- Authors: Bellingan, Terence A , Hugo, Sanet , Villet, Martin H , Weyl, Olaf L F
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441487 , vital:73893 , https://doi.org/10.3389/fenvs.2022.1004939
- Description: Introduced organisms are seen as one of the greatest threats to resource sustainability worldwide, and aquatic macroinvertebrates are regarded as good indicators of the health of water resources. To explore these two perspectives, the responses of macroinvertebrate faunas to native and introduced fishes in three headwater tributaries of the Keiskamma River system, South Africa, were examined by comparing potential indicator communities in reaches considered to be fishless, reaches invaded by introduced salmonid species, and reaches containing native fishes. Patterns in the macroinvertebrate faunal assemblage data were driven strongly by season and flow rate, and less strongly by the presence of insectivorous fishes and biotope availability, a finding in parallel with several similar studies from the region. This affirms that aquatic macroinvertebrate faunas are responsive indicators of both environmental and biotic factors and leaves room for further studies to resolve the effects of non-native fish in the Keiskamma River system and other similar systems from South Africa.
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- Date Issued: 2022
Shrub Detection in High-Resolution Imagery: A Comparative Study of Two Deep Learning Approaches
- Authors: James, Katherine , Bradshaw, Karen L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/440326 , vital:73766 , ISBN 9783030955021 , https://doi.org/10.1007/978-3-030-95502-1_41
- Description: A common task in high-resolution remotely-sensed aerial imagery is the detection of particular target plant species for various ecological and agricultural applications. Although traditionally object-based image analysis approaches have been the most popular method for this task, deep learning approaches such as image patch-based convolutional neural networks (CNNs) have been seen to outperform these older approaches. To a lesser extent, fully convolutional networks (FCNs) that allow for semantic segmentation of images, have also begun to be used in the broader literature. This study investigates patch-based CNNs and FCN-based segmentation for shrub detection, targeting a particular invasive shrub genus. The results show that while a patch-based CNN demonstrates strong performance on ideal image patches, the FCN outperforms this approach on real-world proposed image patches with a 52% higher object-level precision and comparable recall. This indicates that FCN-based segmentation approaches are a promising alternative to patch-based approaches, with the added advantage of not requiring any hand-tuning of a patch proposal algorithm.
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- Date Issued: 2022
Situating the diversity of Southern African environmental education scholarship within a global conversation at a critical juncture on Earth
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389869 , vital:68491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/247386"
- Description: ¬The collection of papers in Volume 38 in many ways mirrors the diversity of research methodologies and teaching approaches in the contemporary eld of Environmental and Sustainability Education. ¬ e seven papers remind us that, whilst environmental educators and researchers are largely in agreement over the nature and causes of the social-ecological problems that we face in sub-Saharan Africa, there is less certainty around what types of educational approaches and pedagogies are adequate to help resolve them. ¬ e papers in this volume either o er pedagogical innovations that may strengthen teaching and learning for sustainable futures, or they provide insights into the social, cultural and economic contexts in which such teaching and learning occurs.
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- Date Issued: 2022
Small but strong: Socioeconomic and ecological resilience of a small European fishing community affected by a submarine volcanic eruption
- Authors: De la Cruz-Modino, Raquel , Piñeiro-Corbeira, Cristina , Gutiérrez-Barroso, Josué , González-Cruz, Carla , Barreiro, Rodolfo , Batista-Medina, José A , Pascual-Fernández, José , González, José A , Santana-Talavera, Agustín , Aswani, Shankar
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391397 , vital:68648 , xlink:href="https://doi.org/10.1016/j.ocecoaman.2022.106124"
- Description: Small-scale coastal fishing communities are facing many new challenges, such as rapid ecological changes created by anthropogenic and natural events like earthquakes or volcanic eruptions. This paper explores how a coastal population has responded to such an event and highlights the diverse coping strategies used to tackle it. This research was conducted on the island of El Hierro (Spain), where a submarine volcanic eruption occurred in 2011, affecting a multiple-use Marine Protected Area (MPA) and the nearby fishing community of La Restinga. Our study illustrates how the local population coped with this situation by combining multiple monetary and non-monetary activities (e.g., informal exchanges) as well as the role of institutions in increasing local resilience by supporting fishers' demands and allowing their participation in the decision-making process in the immediate wake of a catastrophic event. Local families also exploited various natural resources in and near the MPA, thus ensuring access to crucial marine resources and continued recreational/cultural services. The results suggest that collective action played a key role in the recovery process after the eruption, creating some advantages for different local groups despite the hazardous nature of the event.
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- Date Issued: 2022
Sn (IV) porphyrin-biotin decorated nitrogen doped graphene quantum dots nanohybrids for photodynamic therapy
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Balaji, Babu , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230018 , vital:49733 , xlink:href="https://doi.org/10.1016/j.poly.2021.115624"
- Description: Photodynamic therapy (PDT) is a minimally invasive therapeutic procedure for cancer treatment. This study focuses on the synthesis, photophysicochemical properties, and PDT activity of Sn (IV) porphyrin (2), when linked to biotin decorated nitrogen doped graphene quantum dots (B-NGQDs). The porphyrin complex 2 was conjugated through an ester bond to B-NGQDs to form 2-B-NGQDs. Singlet oxygen quantum yield increased for 2 when linked to B-NGQDs to form 2-B-NQGDs. The dark toxicity and photodynamic therapy studies were conducted for 2, NGQDs and their conjugates using MCF-7 breast cancer cells. The cell viability for dark toxicity of all the compounds was above 90%, and 2-B-NGQDs showed high PDT activity at a concentration of 40 µg/mL with cell viability of 22%.
- Full Text:
- Date Issued: 2022