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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

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

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

Review of Importance of Weather and Environmental Variables in Agent-Based Arbovirus Models

- Pascoe, Luba, Clemen, Thomas, Bradshaw, Karen L, Nyambo, Devotha G

  • 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

- Bellingan, Terence A, Hugo, Sanet, Villet, Martin H, Weyl, Olaf L F

  • 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

Situating the diversity of Southern African environmental education scholarship within a global conversation at a critical juncture on Earth

- Olvitt, Lausanne L

  • 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

- 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

  • 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

- Magaela, N Bridged, Matshitse, Refilwe, Balaji, Babu, Managa, Muthumuni, Prinsloo, Earl, Nyokong, Tebello

  • 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%.
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  • Date Issued: 2022

Social-ecological change: insights from the Southern African Program on Ecosystem Change and Society

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

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

- Odame, Felix, Tshentu, Zenixole R, Lobb, Kevin A

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

South African Lagerstätte reveals middle Permian Gondwanan lakeshore ecosystem in exquisite detail

- Prevec, Rosemary, Nel, André, O.Day, Michael, Muir, Robert, Matiwane, Aviwe, Kirkaldy, Abigail P, Moyo, Sydney, Staniczek, Arnold, Cariglino, Bárbara, Maseko, Zolile, Kom, Nokuthula, Rubidge, Bruce S, Garrouste, Romain, Holland, Alexandra J, Barber-James, Helen M

  • Authors: Prevec, Rosemary , Nel, André , O.Day, Michael , Muir, Robert , Matiwane, Aviwe , Kirkaldy, Abigail P , Moyo, Sydney , Staniczek, Arnold , Cariglino, Bárbara , Maseko, Zolile , Kom, Nokuthula , Rubidge, Bruce S , Garrouste, Romain , Holland, Alexandra J , Barber-James, Helen M
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/426673 , vital:72378 , xlink:href="https://doi.org/10.1038/s42003-022-04132-y"
  • Description: Continental ecosystems of the middle Permian Period (273–259 million years ago) are poorly understood. In South Africa, the vertebrate fossil record is well documented for this time interval, but the plants and insects are virtually unknown, and are rare globally. This scarcity of data has hampered studies of the evolution and diversification of life, and has precluded detailed reconstructions and analyses of ecosystems of this critical period in Earth’s history. Here we introduce a new locality in the southern Karoo Basin that is producing exceptionally well-preserved and abundant fossils of novel freshwater and terrestrial insects, arachnids, and plants. Within a robust regional geochronological, geological and biostratigraphic context, this Konservat- and Konzentrat-Lagerstätte offers a unique opportunity for the study and reconstruction of a southern Gondwanan deltaic ecosystem that thrived 266–268 million years ago, and will serve as a high-resolution ecological baseline towards a better understanding of Permian extinction events.
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  • Date Issued: 2022

Stereotyping, Exploitation, and Appropriation of African Traditional Religious Beliefs: The Case of Nyaminyami, Water Spirit, among the Batonga People of Northwestern Zimbabwe, 1860s–1960s

- Matanzima, Joshua

  • Authors: Matanzima, Joshua
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/426543 , vital:72361 , xlink:href="https://doi.org/10.5325/jafrireli.10.1.0072"
  • Description: This article examines the forms of knowledge that existed between Africans and Europeans regarding local indigenous religious beliefs, focusing particularly on the case of Nyaminyami, a water spirit that is part of the belief systems prevalent among some BaTonga people of northwestern Zimbabwe. The article briefly outlines the “traditional” BaTonga beliefs and practices relating to Nyaminyami, which were diametrically opposed to those of the Europeans. It then scrutinizes the ways the beliefs have been exploited and appropriated by different interest groups and races from the 1860s to the 1960s. The BaTonga people, who held strong beliefs in Nyaminyami, and European colonists used the idea of Nyaminyami for different social, political, and environmental agendas prior to, during, and after resettlement. Nyaminyami played changing sociocultural and economic functions for the BaTonga people over time. They revered Nyaminyami as their river god in the nineteenth and twentieth centuries; they also appropriated the beliefs by rallying behind the river god for protection from their displacement in 1958 following the construction of the Kariba Dam on the Zambezi River. Nyaminyami was also appropriated by European interest groups who used the idea of Nyaminyami to cast Africa as the “dark continent” and to stereotype the BaTonga people as primitive. This article relies on data obtained through a reading of European explorers' texts and by gathering oral traditions among the BaTonga and Shangwe.
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  • Date Issued: 2022

Structural modification of RhIIItriarylcorroles for enhanced electrocatalyzed hydrogen evolution reactions

- Zhu, Weihua, Li, Lihua, Wang, Yu, Mack, John, Dingiswayo, Somila, Nyokong, Tebello, Liang, Xu

  • Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
  • Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
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  • Date Issued: 2022

Suitably Strange: Re-imagining learning, scholar-activism, and justice

- McGarry, Dylan K

  • Authors: McGarry, Dylan K
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/371005 , vital:66402 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
  • Description: Using artworks emergent from my career as a pracademic and scholar activist, I attempt to share a ‘tactile theory’ of being and doing, that refer mainly to response-abilities (i.e., abilities to respond in accountable ways) in scholar activist educational sociology. I aim to make visible (and tactile) the sometimes-invisible qualities and practices needed for navigating the eroded and dying ecological relations of our generation, as well as warming up and making pliable the heteronormative, capitalist, patriarchal and anthropocentric conventions that are associated with it. In order to warm and sculpt these normative conventions, I argue for the need for ‘suitably strange’ practice. I present six images and associated prose that aim to optimally disrupt these conventions, towards generative rethinking and embodying learning, scholar activism and justice, and from which I explore a tactile theory, an example and related response-ability for each. I end with a reflection of how these suitably strange artefacts can help us develop a new concept of proactive-cognitive justice or ‘justness’.
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  • Date Issued: 2022

Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid

- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello

  • Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
  • Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
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  • Date Issued: 2022

Synergistic recognition and electrochemical sensing of 17β-Estradiol using ordered molecularly imprinted polymer-graphene oxide-silver nanoparticles composite films

- Regasa, Melkamu Biyana, Nyokong, Tebello

  • Authors: Regasa, Melkamu Biyana , Nyokong, Tebello
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/295829 , vital:57382 , xlink:href="https://doi.org/10.1016/j.jelechem.2022.116713"
  • Description: Synthetic molecularly imprinted polymers (MIPs) based functional materials become the best alternatives to alleviate the stability and cost issues related to biological receptors commonly used in biochemical sensors. To address this demand, we report the development of a highly selective and sensitive MIPs-based electrochemical sensor for the detection of 17β-estradiol (E2). The sensor was prepared based on the MIP-graphene oxide (GO)-silver nanoparticle (AgNP) nanocomposite functional materials electrodeposited on the surface of the glassy carbon electrode (GCE). At first, AgNp formation was facilitated by using ascorbic acid to reduce and stabilize it. A very stable MIP-GO-AgNP sensing layer with multifunctional units were formed using imidazole as a functional monomer (p-type-electron acceptor), GO (n-type-electron donor), and AgNP by using the electrodeposition method. The role of GO in the system is providing additional functional units to bind the template and improve materials morphology while that of AgNPs is acting as a catalyst and charge carrier. The characterization of the sensing materials was done by using Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, and cyclic voltammetry. After optimization of the essential parameters, the sensor was successfully applied to detect the target analyte using the square wave voltammetric technique. The prepared sensor exhibited a wide linear range of 10 fM-250 nM with the limit of detection and limit of quantification of 3.01 fM and 10.03 fM, respectively. The high percentage recoveries, sensitivity, repeatability, and easy fabrication of the MIP-GO-AgNP materials made the proposed sensor promising for environmental monitoring applications in the future.
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  • Date Issued: 2022

Synthesis and conformational studies of 5-bromo-1-[(N-substituted-carbamoyl) methyl]-7-azabenzimidazoles

- Oluwafemi, Kola A, Klein, Rosalyn, Lobb, Kevin A, Tshiwawa, Tendamudzimu, Isaacs, Michelle, Hoppe, Heinrich C, Kaye, Perry T

  • Authors: Oluwafemi, Kola A , Klein, Rosalyn , Lobb, Kevin A , Tshiwawa, Tendamudzimu , Isaacs, Michelle , Hoppe, Heinrich C , Kaye, Perry T
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452800 , vital:75171 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.133811"
  • Description: The Cs2CO3-catalysed condensation of 5-bromo-7-azabenzimidazole with a series of bromomethyl ketones has afforded a small library of ten, novel 5-bromo-1-[(N-substututed-carbamoyl)methyl]-7-azabenzimidazoles. Rotamerism in the products, as evidenced by the splitting of 1H- and 13C-NMR signals, is attributed to hindered internal rotation about the amide N-C(=O) bond, and has been explored using dynamic NMR (DNMR) analysis and computational methods at the GIAO B3LYP/6-311+G(2d,p) level of theory. Coalescence temperatures have been obtained for representative examples and rotational barriers determined experimentally and theoretically. A detailed theoretical analysis has been undertaken to explore conformations which may contribute to the relative populations of the s-cis and s-trans rotamers. The products have also been screened for cytotoxicity and activity against two parasitic protozoan strains (Plasmodium falciparum and Trypanosoma brucei).
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  • Date Issued: 2022

Synthesis of 2, 3-dihydroxy-3-(N-substituted carbamoyl) propylphosphonic acid derivatives as hybrid DOXP-fosmidomycin analogues

- Mutorwa, Marius K, Lobb, Kevin A, Klein, Rosalyn, Blatch, Gregory L, Kaye, Perry T

  • Authors: Mutorwa, Marius K , Lobb, Kevin A , Klein, Rosalyn , Blatch, Gregory L , Kaye, Perry T
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/453212 , vital:75231 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132453"
  • Description: A six-step synthetic pathway has been established to access a series of racemic 2,3-dihydroxy-3-(Nsubstituted carbamoyl)propylphosphonic acid derivatives, designed to contain structural features common to both the natural substrate 1-deoxy-D-xylulose 5-phosphate (DOXP) of the Plasmodium falciparum (Pf) DXR enzyme and its known inhibitor, fosmidomycin. Positive STD-NMR and in silico docking data obtained for some of the compounds indicate their capacity to bind to the analogous E.coli DXR enzyme.
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  • Date Issued: 2022

Synthesis, stereochemistry and in vitro STD NMR and in silico HIV-1 PR enzyme-binding potential of MBH-derived inhibitors

- Tukulula, Matshawandile, Olasupo, Idris A, Mugumbate, Grace C, Lobb, Kevin A, Klein, Rosalyn, Sayed, Yasien, Tshiwawa, Tendamudzimu, Kaye, Perry T

  • Authors: Tukulula, Matshawandile , Olasupo, Idris A , Mugumbate, Grace C , Lobb, Kevin A , Klein, Rosalyn , Sayed, Yasien , Tshiwawa, Tendamudzimu , Kaye, Perry T
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452813 , vital:75172 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.133716"
  • Description: Aza-Michael reactions of a pyridine-3-carbaldehyde-derived Morita-Baylis-Hillman (MBH) adduct with various amines have afforded a series of 10 diastereomeric products, stereochemical analysis of which has been achieved using a combination of NMR (1D, 2D and NOESY) and computer modelling methods. Saturation Transfer Difference (STD) 1H NMR spectroscopy and in silico molecular docking studies have been used to explore the HIV-1 protease sub-type C enzyme binding potential of these compounds in five different HIV-1 PR enzyme receptors.
  • Full Text:
  • Date Issued: 2022

Systematic review of genome-wide association studies of anxiety disorders and neuroticism

- Van Der Walt, Kristien, Campbell, Megan, Stein, Dan J, Dalvie, Shareefa

  • Authors: Van Der Walt, Kristien , Campbell, Megan , Stein, Dan J , Dalvie, Shareefa
  • Date: 2022
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/302532 , vital:58205 , xlink:href="https://doi.org//10.1080/15622975.2022.2099970"
  • Description: Objectives: To summarise SNP associations identified by genome-wide association studies (GWASs) of anxiety disorders and neuroticism; to appraise the quality of individual studies, and to assess the ancestral diversity of study participants. Methods: We searched PubMed, Scopus, PsychInfo and PubPsych for GWASs of anxiety disorders, non-diagnostic traits (such as anxiety sensitivity), and neuroticism, and extracted all SNPs that surpassed genome-wide significance. We graded study quality using Q-genie scores and reviewed the ancestral diversity of included participants. Results: 32 studies met our inclusion criteria. A total of 563 independent significant variants were identified, of which 29 were replicated nominally in independent samples, and 3 were replicated significantly. The studies had good global quality, but many smaller studies were underpowered. Phenotypic heterogeneity for anxiety (and less so for neuroticism) seemed to reflect the complexity of capturing this trait. Ancestral diversity was poor, with 70% of studies including only populations of European ancestry. Conclusion: The functionality of genes identified by GWASs of anxiety and neuroticism deserves further investigation. Future GWASs should have larger sample sizes, more rigorous phenotyping and include more ancestrally diverse population groups.
  • Full Text:
  • Date Issued: 2022
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