Biological control of water lettuce, Pistia stratiotes L., facilitates macroinvertebrate biodiversity recovery: a mesocosm study
- Authors: Coetzee, Julie A , Langa, Susana D , Motitsoe, Samuel N , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423967 , vital:72112 , xlink:href="https://doi.org/10.1007/s10750-020-04369-w"
- Description: Floating aquatic weed infestations have negative socio-economic and environmental consequences to the ecosystems they invade. Despite the long history of invasion by macrophytes, only a few studies focus on their impacts on biodiversity, while the ecological benefits of biological control programmes against these species have been poorly quantified. We investigated the process of biotic homogenization following invasion by Pistia stratiotes on aquatic biodiversity, and recovery provided by biological control of this weed. Biotic homogenization is the increased similarity of biota as a result of introductions of non-native species. The study quantified the effect of P. stratiotes, and its biological control through the introduction of the weevil, Neohydronomus affinis on recruitment of benthic macroinvertebrates to artificial substrates. Mats of P. stratiotes altered the community composition and reduced diversity of benthic macroinvertebrates in comparison to an uninvaded control. However, reduction in percentage cover of the weed through biological control resulted in a significant increase in dissolved oxygen, and recovery of the benthic macroinvertebrate community that was comparable to the uninvaded state. This highlights the process of homogenization by an invasive macrophyte, providing a justification for sustained ecological and restoration efforts in the biological control of P. stratiotes where this plant is problematic.
- Full Text:
- Date Issued: 2020
Encapsulation and physicochemical evaluation of efavirenz in liposomes
- Authors: Okafor, Nnamdi Ikemefuna , Nkanga, Christian I , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183414 , vital:43988 , xlink:href="https://doi.org/10.1007/s40005-019-00458-8"
- Description: Antiretroviral therapy remains the most efective means of managing the human immune defciency virus/acquired immune defciency syndrome (HIV/AIDS). Application of therapeutics has been hampered by factors including poor bioavailability of most anti-retroviral compounds (ARV), side efects and an alarming emergence of drug resistant strains of the virus. Recent developments and use of drug delivery systems (DDS) has shown potential for improving the pharmacological profle of ARV. Amongst these complex DDS, liposomes have been explored for delivery of ARV. In this study, we have aimed at exploring efcient encapsulation of efavirenz (EFV), a potent ARV using diferent mass ratios of crude soybean lecithin and cholesterol. The EFV-loaded liposomes (EFL) were prepared using thin flm hydration and evaluated for particle size, zeta potential (ZP), encapsulation efciency (EE%), morphology and drug release studies. Diferential scanning calorimetry (DSC), X-ray difraction (XRD), energy dispersity spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy were used for comprehensive physicochemical characterization of EFL. EFL exhibited high encapsulation (99%) in 1:1 crude lecithin to cholesterol mass ratio. The average particle size and Zeta Potential of EFL were found to be 411.10±7.40 nm and −53.5.3±0.06 mV, respectively. EFL showed a relatively controlled EFV release behaviour that was similar to the dissolution profle of un-encapsulated EFV. This suggests that EFL represents a promising vehicle for efective EFV delivery while providing the advantages of a nano-scaled delivery system
- Full Text:
- Date Issued: 2020
Exploring how a genetic attribution to disease relates to stigma experiences of Xhosa patients with schizophrenia in South Africa
- Authors: Matshabane, Olivia P , Campbell, Megan , Faure, Marlyn C , Marshall, Patricia A , Mayosi, Bongani M , Stein, Dan J , Appelbaum, Paul S , de Vries, Jantina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302487 , vital:58201 , xlink:href="https://doi.org/10.1007/s00127-020-01875-z"
- Description: Background: Over the past three decades, a range of international stakeholders have highlighted the possibility that genomic research may impact stigma associated with psychiatric disorders. Limited research has been conducted in Africa to investigate this relation. Method In the present study, using focus group discussions, we explored the relation between genetic attribution and stigma among 36 Xhosa people with schizophrenia. We addressed three main questions: (1) What causal beliefs do Xhosa people with schizophrenia use to explain their illness and to what extent do genetic explanations play a role in these beliefs? (2) What are the internalised stigma experiences of Xhosa people with schizophrenia? (3) How do genetic explanations relate to stigma experiences, if at all? Results Most participants were able to define genetics and some linked genetics to disease causation. Despite adequate knowledge of genetics and an emphasis on genetic explanations of schizophrenia in the study, most participants held a multitude of causal explanations including: psychosocial, environmental, and cultural. Moreover, participants rarely mentioned disease cause when describing their stigma experiences. Discussion For this population group, there was no straight-forward relation between a genetic attribution and stigma. Therefore, we did not fnd evidence that genetic attribution may signifcantly increase stigma. Although North American and European literature provides conficting evidence regarding this relation, there is increased consensus that biomedical explanations for psychiatric disorders may reduce blame. This study found evidence supporting that consensus. This study provides an empirical foundation to inform ongoing work on the psychosocial implications of psychiatric genomics research in non-Western contexts.
- Full Text:
- Date Issued: 2020
Nutrient-mediated silica uptake from agricultural runoff in invasive floating macrophytes: implications for biological control
- Authors: Baso, Nompumelelo C , Delport, Garyn A , Coetzee, Julie A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424803 , vital:72185 , xlink:href="https://doi.org/10.1007/s10750-020-04344-5"
- Description: Silica (Si) plays a significant role in alleviating the effects of biotic and abiotic stressors in many plants, especially in an agricultural context. With increased use of Si-based fertilisers, understanding plant responses to the addition of Si to their environment, particularly aquatic environments, is important. We investigated how two invasive macrophytes, Eichhornia crassipes and Pistia stratiotes, responded to different nutrient and Si concentrations, in the presence and absence of herbivory. Both species incorporated Si into their foliage, but uptake of Si did not increase under high nutrient availability but rather decreased, especially in P. stratiotes. Plant quality (i.e. C:N) for both weed species was affected more by nutrient concentrations than Si content, and the addition of Si had a negative effect on plant growth. Eichhornia crassipes increased daughter plant production under high Si conditions, while P. stratiotes plants showed no reproductive response to increased Si except in low nutrient conditions where reproduction was reduced. The addition of Si resulted in increased biomass of E. crassipes, while P. stratiotes was unaffected. These results highlight that runoff of Si from fertiliser alter aquatic plant–insect interactions, which has consequences for biological control.
- Full Text:
- Date Issued: 2020
Paul Ashwin Transforming university education, a manifesto: A review
- Authors: McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185886 , vital:44445 , xlink:href="https://doi.org/10.1007/s10734-020-00641-z"
- Description: This book is wide-ranging in its focus. It tackles student-centeredness, graduate premiums, credentialing, quality assurance, big data and rankings, and yet it offers a coherent engagement with these and many other contemporary issues. The coherence is brought about by the consistent application of one central idea throughout the book. That is that the value of higher education for both the individual and for society is that it brings the graduate into a transformational relationship with knowledge that changes their sense of who they are and thereby makes possible their doing all number of things in the world.
- Full Text:
- Date Issued: 2020
Plant-Based Synthesis of Silver Nanoparticles Using Aqueous Leaf Extract of Salvia officinalis: Characterization and its Antiplasmodial Activity
- Authors: Okaiyeto, Kunle , Hoppe, Heinrich C , Okoh, Anthony I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429472 , vital:72613 , xlink:href="https://doi.org/10.1007/s10876-020-01766-y"
- Description: In the present study, an aqueous leaf extract of Salvia officinalis was used to synthesize silver nanoparticles (AgNPs) and characterized with different techniques such as UV–vis spectroscopy, Fourier transform infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray spectroscopy (EDX), Transmission electron microscope (TEM) and thermogravimetric analysis (TGA). Subsequently, its cytotoxic effect against human cervix adenocarcinoma (HeLa) cells and antiplasmodial activity against Plasmodium falciparum were investigated. UV–vis spectrum of AgNPs displayed an absorption peak at 323 nm and TEM result revealed it to be spherical in shape with average size of 41 nm. FTIR results highlighted the key bioactive compounds that could be responsible for the reduction and capping of AgNPs and XRD analysis showed its crystalline nature with a face-centered cubic (fcc) structure. The synthesized AgNPs was found to be less cytotoxic against HeLa cells line and demonstrated good antiplasmodial potential (IC50 = 3.6 µg/mL). Findings from this study indicated that the AgNPs could serve as a template in the development of new drugs for the control of malaria and hence, further study is needed to identify and characterize the potent molecules that suppress the malaria parasite.
- Full Text:
- Date Issued: 2020
Synthesis of novel Schiff base cobalt (II) and iron (iii) complexes as cathode catalysts for microbial fuel cell applications
- Authors: Sen, Pinar , Akagunduz, Dilan , Aghdam, Araz S , Cebeci, Fevzi C , Nyokong, Tebello , Catal, Tunc
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190861 , vital:45035 , xlink:href="https://doi.org/10.1007/s10904-019-01286-x"
- Description: In this study, the synthesis and characterization of a new Schiff base and its cobalt(II) and iron(III) complexes were performed fully characterized by common spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, UV–Vis and MS and elemental analysis. The cathodes prepared with only activated carbon, Co-Schiff base complex, and Fe-Schiff base complex mixed with activated carbon as the carrier were examined in single chamber air cathode microbial fuel cells (MFCs). The spectroscopic results confirm the structure of novel Schiff base and its complexes with cobalt (II) and Fe(III). MFC results showed that Fe-Schiff base complex generated higher voltage generation using glucose as the carbon source. Cyclic voltammetry results showed the conductivity and catalytic features of the cathodes developed in this study. Scanning electron microscopic results showed the distribution the complexes on the cathode surface. In conclusion, a novel Schiff base and its complexes with cobalt (II) and iron (III) can be employed into MFC technology to be used in green electricity production, and might help decreasing the operating costs of wastewater treatment plants.
- Full Text:
- Date Issued: 2020
The conundrums of counselling women in violent intimate partner relationships in South Africa: implications for practice
- Authors: Fleischack, Anne , Macleod, Catriona I , Böhmke, Werner
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444117 , vital:74191 , xlink:href="https://doi.org/10.1007/s10447-019-09384-8"
- Description: Little research focuses on how counsellors experience counselling encounters concerning intimate partner violence. This study reports on narrative research conducted with eight South African non-governmental organisation counsellors. Participants spoke of creating productive and caring counselling dynamics, and providing non-directive counselling. However, they also indicated providing moral guidance, particularly in cases where pregnancy or children were involved. Success was viewed rather narrowly as the women leaving the relationship, setting up ‘all-or-nothing’ outcomes. Such ‘success’ led to counsellor happiness, whilst failure in this regard led to counsellors experiencing anger and burn-out. We conclude that the conundrums evident in these data are grounded in patriarchal systems, limiting the efficacy of counselling based on a bondage and deliverance narrative. Implications for practice and training are also outlined.
- Full Text:
- Date Issued: 2020
Young people and environmental affordances in urban sustainable development
- Authors: Nissen, Sylvia , Prendergast, Kate , Aoyagi, Midori , Burningham, Kate , Hasan, Mohammed Mehedi , Hayward, Bronwyn , Jackson, Tim , Jha, Vimlendu , Mattar, Helio , Schudel, Ingrid J , Venn, Sue , Yoshida, Aya
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/294460 , vital:57223 , xlink:href="https://doi.org/10.1186/s42055-020-00039-w"
- Description: Background: Cities are at the fore of sustainability challenges of the twenty-first century, and many, particularly in Asia and Africa, are predominantly youthful spaces. Understanding young people's experiences in urban environments is therefore important as we strive to achieve both the Sustainable Development Goals and the Paris Agreement. Two amenities identified in the urban Sustainable Development Goal 11, transport and public and green space, are specifically recognised as applying to youth. Yet, there is little analysis that explicitly considers how youth experience these amenities across the Global North and South, and no current measures for understanding progress in youth experiences of green space and transport. Results: This paper provides a comparative analysis of young people's experiences with local transport and green space in seven diverse urban communities (Christchurch, New Zealand; Dhaka, Bangladesh; Lambeth/London, UK; Makhanda, South Africa; New Delhi, India; São Paulo, Brazil; and Yokohama, Japan). Our study contributes to a growing body of literature that seeks to listen to child and youth perspectives to understand their environmental experiences. We examine the 'affordances' young residents aged 12 to 24 years currently associate with green space and transport amenities. Affordances are defined here as the inter-relationships between what a local environment offers young people and their perceptions and actions. Drawing on focus groups and interviews conducted with 332 young people, we identify five affordances young people associate in relation to transport and public space across these diverse urban settings: (1) social inclusion and belonging; (2) autonomy; (3) physical comfort and security; (4) relaxation and reflection; and (5) health and fitness. Conclusions The paper contributes to growing interdisciplinary research interest in measuring affordances as a way to advance the Sustainable Development Goals in an urban context. In providing a comparative account of young people's experiences across diverse contexts, our discussion highlights how affordances in relation to transport or public and green space can help understand the multiple interconnections between the well-being of young people and sustainability. In particular, we argue that it is not merely the provision of transport or public and green space that matters, but the nuanced meaning of places and experiences as understood by local communities that needs to be recognised if we are to better support urban youth wellbeing and advance sustainable development goals.
- Full Text:
- Date Issued: 2020