List of Titles

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

- Makola, Lekgowa Collen, Nwahahra, Nnamdi, Managa, Muthumuni, Nyokong, Tebello

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

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Photodynamic therapy characteristics of phthalocyanines in the presence of boron doped detonation nanodiamonds

- Matshitse, Refilwe, Nwaji, Njemuwa, Managa, Muthimuni, Chen, Zhi-Long, Nyokong, Tebello

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

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Phthalocyanine based fabricated exfoliated graphite photoanode for electrodegradation of 4-acetamidophenol under visible light irradiation

- Mpeta, Lekhetho S, Nyokong, Tebello

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

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Plagiarism and the commodification of knowledge

- McKenna, Sioux

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

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Planetary Urgency, Researcher Reflexivity and ESE Research: Questions Arising from an Initial Exploration of Goethean-inspired Phenomenology

- Olvitt, Lausanne L

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

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Plant disease detection using multispectral imaging

- De Silva, Malitha, Brown, Dane L

Authors: De Silva, Malitha , Brown, Dane L
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/463439 , vital:76409 , xlink:href="https://link.springer.com/chapter/10.1007/978-3-031-35641-4_24"
Description: People worldwide are undergoing many challenges, including food scarcity. Many pieces of research are now focused on improving agriculture to increase the harvest and reduce the cost. Identifying plant diseases and pests in the early stages helps to enhance the yield and reduce costs. However, most plant disease identification research with computer vision has been done with images taken in controlled environments on publically available data sets. Near-Infrared (NIR) imaging is a favourable approach for identifying plant diseases. Therefore, this study collected NIR images of healthy and diseased leaves in the natural environment. The dataset is tested with eight Convolutional Neural Network (CNN) models with different train-test splits ranging from 10:90 to 90:10. The evaluated models attained their highest training and test accuracies from the 70:30 split onwards. Xception outperformed all the other models in all train-test splits and achieved 100% accuracy, precision and recall in the 80:20 train-test split.
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Date Issued: 2022

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Postgraduate education in a globalised world

- Boughey, Chrissie

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

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Preparation, characterization, and in vitro evaluation of polymer-based wound dressings for the management of chronic wounds

- Alven, Sibusiso

Authors: Alven, Sibusiso
Date: 2022
Subjects: Toxicity testing -- In vitro , Wound healing , Chronic diseases
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/27992 , vital:71414
Description: Microbial infections are responsible for the retarded recovery process of chronic wounds. Polymer-based scaffolds possess features suitable for the treatment of chronic injuries. However, these scaffolds are commonly encapsulated with therapeutic agents to enhance their biological activities, including antibacterial efficacy. In this research, two types of polymer-based scaffolds were formulated and evaluated as effective formulations for the treatment of chronic wounds: sponges and topical gels. Sponges were formulated from cross-linking of gelatin and PEG. Ag nanoparticles and metronidazole were incorporated into the sponges to improve their antibacterial activity. Topical gels were loaded with essential oils and Ag nanoparticles and prepared from CMC and poloxamer. The prepared sponges and topical gels were evaluated using various analysis and characterization techniques. SEM/EDX, FTIR, and TGA were employed to characterize gelatin/PEG hybrid sponges followed by porosity, in vitro biodegradability, cytotoxicity, and antibacterial studies. FTIR, SEM/EDX, and TGA confirmed their physicochemical properties and successful fabrication of sponges loaded with metronidazole and Ag nanoparticles. The sponges were biodegradable, indicating their capability to induce skin regeneration. The drug release studies showed a rapid release of metronidazole 28.32-71.97 percent from the sponges over the first hour, followed by a sustained drug release. The Ag nanoparticles were released in a sustained manner, suggesting that these sponges can rapidly destroy bacteria and inhibit persisting bacterial infections as well as protect the lesion bed from further bacteria infections. The in vitro antibacterial studies of sponges displayed superior antibacterial activity against most of the Gram-negative and Gram-positive bacteria strains commonly found in chronic wound infections with a MIC value of 15.625 μg/mL. In vitro cytotoxicity experiments revealed excellent biocompatibility with a percent cell viability of more than 70 percent. The in vitro wound scratch healing assay exhibited that the sponges encapsulated with only metronidazole promoted high cell migration than the dual drug-loaded sponges and untreated cells, suggesting its potential to quicken the wound healing process. CMC/Poloxamer topical gels were also characterized by FTIR, followed by pH, viscosity, spreadability, cytotoxicity, and antibacterial studies. FTIR showed successful preparation of CMC/Poloxamer topical gels loaded with essential oils and Ag nanoparticles. The topical gels exhibited pH in the range of 5.20-6.68, spreadability between 5.4 and 5.9 cm, and viscosity ranged from 216 to 1200 cP at 50 rpm and 210–858 cP at 100 rpm. The in vitro drug release studies demonstrated that Ag nanoparticles were released from the topical gels in a sustained manner. Most formulated topical gels demonstrated superior antimicrobial efficacy against Gram-positive and Gram-negative bacteria strains than the blank gel and controls. The cytotoxicity analysis displayed more than 90.83 percent cell viability for the topical gels, revealing excellent biocompatibility. The outcomes revealed that the topical gels enriched with essential oils lavender and tea tree and Ag nanoparticles and sponges incorporated with metronidazole and Ag nanoparticles are potential wound dressing scaffolds that can be employed for the treatment of chronic infected injuries. The in vitro wound healing experiments showed that the HaCaT cells cultured with gels co-enriched with lavender oil and Ag nanoparticles possessed a higher rate of closure in comparison to the untreated cells for 96 hours. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
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Date Issued: 2022

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Principles of Computer Architecture

- Machanick, Philip

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

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Promotion of Catalytic Oxygen Reduction Reactions

- Wei, Yuqin, Zhao, Long, Yuan, Rui, Xue, Zhaoli, Mack, John, Chivumba, Choonzo, Nyokong, Tebello, Zhang, Jianming

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

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Reaction of Perrhenate with Phthalocyanine Derivatives in the Presence of Reducing Agents and Rhenium Oxide Nanoparticles in Biomedical Applications

- 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

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

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Refining youth sexualities empowerment programmes: The development of the Masizixhobise Toolkit based on a critical sexual and reproductive citizenship framework

- Macleod, Catriona I, Moore, Sarah-Ann

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

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Reflections from early-career researchers on the past, present and future of doctoral education

- 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

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

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Regioselectivity, chemical bonding and physical nature of the interaction between imidazole and XAHs (X= H, F, Cl, Br, CH3, and A= S, Se, Te)

- Isamura, Bienfait K, Lobb, Kevin A, Muya, Jules T

Authors: Isamura, Bienfait K , Lobb, Kevin A , Muya, Jules T
Date: 2022
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/453183 , vital:75229 , xlink:href="https://doi.org/10.1080/00268976.2022.2026511"
Description: Theambidentreactivityofsmall-sizedXAHs(X=H,F,Cl,Br,CH3,andA=S,Se,Te)moleculestowardsthe imidazole molecule (IMZ) has been investigated using wave function (MP2) and Density Func-tional Theory (B3LYP, B3LYP-D3). Molecular electrostatic potentials (MEPs) and frontier molecularorbitals of monomers are computed to rationalise the regioselectivity of IMZ towards XAHs. Thechemical bonding of each complex is described in the framework of the quantum theory of atomsin molecules (QTAIM) and natural bond orbital (NBO) paradigms. The symmetry-adapted pertur-bation theory (SAPT) is employed to assess the physical nature of the interactions. Our findingssuggest that XAHs mainly bind to IMZ through H-bonding and chalcogen-bonding interactionsof weak to moderate strength, with binding energies ranging from−3.1 to−17.6 kcal/mol at theMP2/aug-cc-pVDZ(-PP) level. Topological QTAIM descriptors reveal all H-bonds between IMZ andXAHs to be purely noncovalent contacts, while chalcogen bonds of halogenated XAHs (X=F, Cl, Br) show a partial covalent character. SAPT2 calculations indicate that both H-bonded and chalcogen-bonded complexes are mainly stabilised by electrostatic interactions. Insights drawn from this studyare expected to constitute the bedrock for further investigations about noncovalent interactionbetween middle to big-sized chalcogen-containing molecules and imidazole derivatives.
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Date Issued: 2022

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Reproductive health systems analyses and the reparative reproductive justice approach: a case study of unsafe abortion in Lesotho

- Macleod, Catriona I, Reynolds, John H

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

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