List of Titles

Biocompatibility of biomaterials for nanoencapsulation: Current approaches

- Witika, Bwalya A, Makoni, Pedzisai A, Matafwali, Scott K, Chabalenge, Billy, Mwila, Chiluba, Kalungia, Aubrey C, Nkanga, Christian I, Bapolisi, Alain M, Walker, Roderick B

Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
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Date Issued: 2020

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Bioelectrocatalysis and surface analysis of gold coated with nickel oxide/hydroxide and glucose oxidase towards detection of glucose:

- Njoko, Nqobile, Louzada, Marcel, Britton, Jonathan, Khene, Samson M, Nyokong, Tebello, Mashazi, Philani N

Authors: Njoko, Nqobile , Louzada, Marcel , Britton, Jonathan , Khene, Samson M , Nyokong, Tebello , Mashazi, Philani N
Date: 2020
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/150071 , vital:38937 , https://doi.org/10.1016/j.colsurfb.2020.110981
Description: The fabricating of metal oxide thin films onto conducting surfaces continues to grow and their potential applications as surfaces for biosensor applications is of paramount importance. The correct orientation of glucose oxidase redox enzymes yields very important biointerfaces capable of selectively detecting D-glucose as a measure of blood sugar for healthy and diabetic sick patients. The electrodeposition of redox enzymes, such as glucose oxidase enzymes, onto gold electrode surfaces pre-modified with nickel oxide was investigated in this work.
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Date Issued: 2020

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Biological control of water lettuce, Pistia stratiotes L., facilitates macroinvertebrate biodiversity recovery: a mesocosm study

- Coetzee, Julie A, Langa, Susana D, Motitsoe, Samuel F, Hill, Martin P

Authors: Coetzee, Julie A , Langa, Susana D , Motitsoe, Samuel F , 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.
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Date Issued: 2020

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Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys)

- Taylor, Peter J, Kearney, Theresa, Dalton, Desire L, Chakona, Gamuchirai, Kelly, Christopher M, Barker, Nigel P

Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M , Barker, Nigel P
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
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Date Issued: 2020

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BODIPY dyes for application in the photo-oxidation of pollutants, photodynamic antimicrobial chemotherapy, and nonlinear optics

- Kelechi, Lebechi Augustus

Authors: Kelechi, Lebechi Augustus
Date: 2020
Subjects: Dyes and dyeing -- Chemistry , Fluorescent probes , Fluorescence spectroscopy
Language: English
Type: text , Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10962/140298 , vital:37859
Description: The synthesis and structural characterization of a series of BODIPY dyes to analyze both the effects of halogenations at the 2,6-positions and the introduction of styryl groups at the 3,5-positions. The photophysical properties of these dyes were investigated to determine their suitability as singlet oxygen-generating photosensitiser dyes for application in photocatalytic degradation of azo dyes and in photodynamic antimicrobial chemotherapy (PACT). Upon halogenation, the dyes showed high to moderate singlet oxygen quantum yields. The potential utility of electrospun polystyrene (PS) nanofibres embedded with halogenated BODIPY dyes for the photocatalytic degradation of Orange G and Methyl Orange from textile industry effluents were investigated. A comparison of the singlet oxygen quantum yield of the BODIPY dyes in solution and when embedded in the PS nanofibres support demonstrates that its photosensitiser properties are maintained in the nanofibre mats. The photocatalytic degradation properties of the PS nanofibres for Orange G and Methyl Orange were determined by using a 530 nm and 660 nm light-emitting diodes. The rate of photodegradation increases with both the Orange G and Methyl Orange concentrations and follows pseudo-first-order kinetics. The PACT activities of brominated BODIPYs on Escherichia coli and Staphylococcus aureus were investigated. Log reduction values of over 9 were obtained during the photoinactivation of Staphylococcus aureus. To be able to red-shift the main spectral band of the BODIPY dyes into the therapeutic window, styryl groups were introduced at the 3,5-positions through a modified Knoevenagel condensation reaction. Because the red-shifted spectral band lies above 532 nm, the second harmonic of the Nd:YAG laser, there is very minute absorption at this wavelength. One of the novel brominated BODIPY dyes was investigated for its potential utility as optical limiting materials in nonlinear optics (NLO), and the dyes demonstrated typical nonlinear absorption behaviour characterised by reverse saturable absorption (RSA) in Z-scan measurements. Excellent optical limiting parameters were obtained for third-order susceptibility and hyperpolarisability.
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Date Issued: 2020

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BTC price volatility: fundamentals versus information

- Gbadebo, Adedeji Daniel, Adekunle, Ahmed Oluwatobi, Adebayo-Oke Abdulrauf Lukman, Adedokun, Wole, Akande, Joseph

Authors: Gbadebo, Adedeji Daniel , Adekunle, Ahmed Oluwatobi , Adebayo-Oke Abdulrauf Lukman , Adedokun, Wole , Akande, Joseph
Date: 2020
Subjects: Bitcoin price volatility , Bitcoin market fundamentals , Autoregressive Distributed Lag (ARDL)
Language: English
Type: article , text
Identifier: http://hdl.handle.net/11260/6978 , vital:52630 , https://doi.org/10.1080/23311975.2021.1984624
Description: This paper offers a plausible response to “what explains the sporadic volatility in the price of Bitcoin?” We hypothesized that market “fundamentals” and “information demands” are key drivers of Bitcoin’s unpredictable price fluctuation. We adopt the transfer-function [Autoregressive Distributed Lag, ARDL] model and its Bounds testing approach to verify how the volatility of the price of Bitcoin responds to its transaction volume, cryptocurrency market capitalisation, world market equity index and Google search. We found the existence of long-run cointegration relation and observed that all the variables except the equity index positively explain the volatility of Bitcoin price. The result established evidence that market fundamentals drive erratic swing in Bitcoin price than information.
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Date Issued: 2020

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Building a flexible and inexpensive multi-layer switch for software-defined networks

- Magwenzi, Tinashe

Authors: Magwenzi, Tinashe
Date: 2020
Subjects: Software-defined networking (Computer network technology) , Telecommunication -- Switching systems , OpenFlow (Computer network protocol) , Local area networks (Computer networks)
Language: English
Type: text , Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10962/142841 , vital:38122
Description: Software-Defined Networking (SDN) is a paradigm which enables the realisation of programmable network through the separation of the control logic from the forwarding functions. This separation is a departure from the traditional architecture. Much of the work done in SDN enabled devices has concentrated on higher end, high speed networks (10s GBit/s 100s GBit/s), rather than the relatively low bandwidth links (10s MBit/s to a few GBit/s) which are seen, for example, in South Africa. As SDN is increasingly becoming more accepted, due to its advantages over the traditional networks, it has been adopted for industrial purposes such as networking in data centres and network providers. The demand for programmable networks is increasing but is limited by the ability of providers to upgrade their infrastructure. In addition, as access to the Internet has become less expensive, the use of Internet is increasing in academic institutions, NGOs, and small to medium enterprises. This thesis details a means of building and managing a small scale Software-Defined Network using commodity hardware and open source tools. Core to the SDN Network illustrated in this thesis is the prototype of a multi-layer SDN switch. The proposed device is targeted to serve lower bandwidth communication (in relation to commercially produced high speed SDN-enabled devices). The performance of the prototype multilayer switch had shown to achieve: data-rates of up to 99.998%, average latencies that are under 40µs during forwarding/switching and under 100µs during routing while using packet sizes between 64 bytes and 1518 bytes, and a jitter of less than 15µs during all tests. This research explores in detail the design, development, and management of a multi-layer switch and its placement and integration in small scale SDN network. This includes testing of Layer 2 forwarding and Layer 3 routing, OpenFlow compliance testing, the management of the switch using created SDN applications, and real life network functionality such as forwarding, routing and VLAN networking to demonstrate its real world applicability.
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Date Issued: 2020

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Can fishing tourism contribute to conservation and sustainability via ecotourism?: a case study of the Fishery for Giant African Threadfin Polydactylus quadrifilis on the Kwanza Estuary, Angola

- Butler, Edward C, Childs, Amber-Robyn, Saayman, Andrea, Potts, Warren M

Authors: Butler, Edward C , Childs, Amber-Robyn , Saayman, Andrea , Potts, Warren M
Date: 2020
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/149253 , vital:38819 , https://doi.org/10.3390/su12104221
Description: It has been suggested that tourism fisheries can raise the value of landed catch, provide alternative livelihoods for local artisanal fishers and, because recreationally caught fishes are often released, simultaneously conserve stocks. However, for fishing tourism to meet ecotourism standards, sustainable, local economic benefit is imperative. This study aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary, Angola. The recreational fishery contributed significantly to economic productivity in an otherwise rural area, generating a total revenue (TR) of $236,826 per four-month fishing season.
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Date Issued: 2020

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Carnivore intra-guild competition in Selati Game Reserve, Limpopo Province, South Africa

- Comley, Jessica

Authors: Comley, Jessica
Date: 2020
Subjects: Hyenas -- Behavior -- South Africa , Hyenas -- South Africa , Hyenas -- Ecology -- South Africa , Top predators -- South Africa , Top predators -- Ecology -- South Africa , Animal communities -- South Africa , Animal behavior -- South Africa , Mutualism (Biology) -- South Africa , Coexistence of species -- South Africa , Game farms -- South Africa , Selati Game Reserve (South Africa)
Language: English
Type: text , Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10962/115558 , vital:34163
Description: Carnivore intra-guild interactions can be important drivers of carnivore community composition and ecosystem functioning. Large carnivores are particularly important since they occupy the highest trophic levels and can exert extensive influences on subordinate carnivores and prey species. Given Africa’s rapidly expanding human population, enclosed reserves such as those found in South Africa, may become increasingly important for carnivore conservation. A major concern, however, is that the interactions and co-existence of multiple carnivores in these systems is poorly understood. Additionally, the majority of reserves in South Africa are small ( 400km²), potentially increasing the likelihood of competition. My research aimed to provide insight into the interactions and co-existence of a multi-carnivore community within a small, enclosed reserve in South Africa (Selati Game Reserve). I tackled this task by using a combination of field techniques including camera trap surveys, ungulate transect surveys, aerial count surveys, location data collected from collared large carnivores and scat and kill site analyses. I found that carnivore-carnivore interactions, and their associated impacts, varied within the carnivore guild and that co-existence may be due to trade-offs between various risks (i.e. interference and exploitative competition) and benefits (i.e. resources such as food and space). My findings also revealed that large carnivores, such as lions (Panthera leo), spotted hyaenas (Crocuta crocuta) and leopards (Panthera pardus) do not have homogenous effects and that site-specific research on multiple-carnivores is integral for conserving biodiversity and ecosystem dynamics. Lions were the dominant large carnivore (in terms of intra-guild predation, space use and resource use) despite being outnumbered seven to one by spotted hyaenas. Leopard occupancy was negatively influenced by lions and leopard diet overlapped almost completely (91%) with spotted hyaenas, suggesting increased kleptoparasitism of leopard kills by spotted hyaenas. While my study provides valuable insight into the complexity of carnivore intra-guild competition in a small, enclosed reserve it also highlights major research gaps and emphasises the need for ecosystem-based research throughout southern Africa to fully understand how multiple sympatric carnivores co-exist in these systems.
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Date Issued: 2020

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Charlie Hebdo as a critical event in a secondary school: Muslim students’ complex positioning in relation to the attack

- Tize, Carola, Berckmoes, Lidewyde, de Jong, Joop, Reis, Ria

Authors: Tize, Carola , Berckmoes, Lidewyde , de Jong, Joop , Reis, Ria
Date: 2020
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/156400 , vital:39986 , DOI: 10.1177/1363461520903814
Description: This paper examines responses to the 2015 terror attack on Charlie Hebdo, a French satirical magazine, amongst students in a secondary school in Berlin-Neukölln, Germany. The Charlie Hebdo attack occurred in the final weeks of a 19-month ethnographic study in the community. By analyzing the responses in the school to this critical event, we identify what is at stake for Muslim students.
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Date Issued: 2020

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Chemical archeoceanography:

- Albarede, Francis, Thibon, Fanny, Blichert-Toft, Janne, Tsikos, Harilaos

Authors: Albarede, Francis , Thibon, Fanny , Blichert-Toft, Janne , Tsikos, Harilaos
Date: 2020
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/149065 , vital:38801 , https://doi.org/10.1016/j.chemgeo.2020.119625
Description: Elemental fluxes to the ocean are expected to increase with the surface area of continental exposure to weathering and atmospheric PCO2. The record of phosphorus in sediments, which has no notable source within the ocean, and the radiogenic strontium isotopes in Archean carbonates indicate that, prior to the Great Oxidation Event (GOE), subaerial expanses represented only about 20% of the modern continental surface area, i.e. 7% of the surface of the Earth. Because these simple first-order observations, in contrast to the low oxygen content of the pre-GOE atmosphere, have so far received only little attention in the appraisal of the marine chemistry of the early Earth, a reassessment of the chemistry of the pre-GOE ocean is warranted. Here we discuss some of the geochemical cycles of the Archean world, including protons, alkalinity, electrons, and other electrolytes, and attempt to build a first conceptual framework for Chemical Archeoceanography.
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Date Issued: 2020

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Chirema Chine Mazano Chinotamba Chakazendama Madziro

- Mapondera, Wallen

Authors: Mapondera, Wallen
Date: 2020
Subjects: Art, Zimbabwean , Art -- Economic aspects -- Zimbabwe , Artists -- Zimbabwe , Takadiwa, Moffet , Nyandoro, Gareth , Clottey, Serge Attiku , Mapondera, Wallen -- Exhibitions
Language: English
Type: text , Thesis , Masters , MFA
Identifier: http://hdl.handle.net/10962/147457 , vital:38638
Description: This mini-thesis has developed as a practice-based supporting document to the exhibition Chirema Chine Mazano Chinotamba Chakazendama Madziro. The exhibition responds to how people become innovative in finding alternative means of survival and staying relevant in an economically depressed country. Zimbabwe is often the first country that comes to mind when people talk about hyperinflation; the situation was and still is intolerable, but somehow its citizens find means to pull through. Unemployment and poverty are the main causes of physical and mental problems for an individual. With this thesis, I highlight the innovations employed by Zimbabweans as a way of keeping themselves busy. I approach this through analysing the Zimbabwean general public’s creative reactions, and by tracing Zimbabwean visual artists’ use of found objects as a reaction to the country’s economic hardships. As people have been pushed to find alternative ways of survival, Zimbabwean artists in particular also shifted from using conventional art materials due to their unavailability. They began to redefine what art material is by employing objects in their artworks that previously had a non-art function. As such, there is a growing need to recognise, classify and document the shifts and establish platforms to generate growth of these innovations. In this minithesis I discuss my own practice, and I analyse the works of Moffat Takadiwa, Gareth Nyandoro and Serge Attiku Clottey.
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Date Issued: 2020

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Choreographies of protest performance as recruitment to activism and the movement of perception during the 2015 re-emergence of student activism at Rhodes University

- Qoza, Phiwokazi

Authors: Qoza, Phiwokazi
Date: 2020
Subjects: College students -- Political activity -- South Africa , Student protesters -- South Africa , Student movements -- South Africa , Higher education and state -- South Africa , Performance art -- Political aspects -- South Africa , Protest songs -- South Africa
Language: English
Type: text , Thesis , Masters , MA
Identifier: http://hdl.handle.net/10962/141692 , vital:37997
Description: It has been argued that individuals participate in activism due to an identification with the preferences and interests of an emerging group of actors or in solidarity with a pre-existing network that has resorted to a number of protest repertoires in order to make claims or demands. Additionally, an emerging instance of protest is often linked to an image of previous protest events through the employment of a combination of master frames which function as discursive articulation of the encounter in familiar terms, creating a frame resonance which recruits adherents and constituents. To understand why some bystanders to protest transcended to actors in protest and the development of frames within a protest cycle, a performance ethnography is employed to observe and analyse choreographies of protest which took place at an institution of higher education in South Africa during the 2015 re-emergence of wide-spread student activism. It is found that in encountering an atmosphere of protest there emerged a relation of feeling, referred to as “feeling the vibe or atmosphere”, which those who became protest performers resolved in ways which increased their capacity to act in favour of co-constituting that atmosphere. During the encounter between the bystander body and the atmosphere of protest, non-linear somatic communication, characterised by active and passive gestures and postures, occurred through which protest performers developed contact and connection with other bodies as a result of the displacement of space. This thesis suggests that participation in activism can be about going with the flow of movement in an uncertain and ambiguous moment and is not limited to an identification with the pre-existing organization of preferences and interests as a frame of resonance emerges to signify somatic communication which differentiated bodies in the duration of protest performance. Therefore, this thesis uses the theory of affect to situate student activism in-between the politics of performance and the performance of politics whereupon the rhythm of song creates an opening for the kinaesthetic to create form from spontaneous movement of the body as an event of the movement of perception and the perception of movement.
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Date Issued: 2020

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Climate modelling suggests a review of the legal status of Brazilian pepper Schinus terebinthifolia in South Africa is required:

- Martin, Grant D, Magengelele, Nwabisa L, Paterson, Iain D, Sutton, Guy F

Authors: Martin, Grant D , Magengelele, Nwabisa L , Paterson, Iain D , Sutton, Guy F
Date: 2020
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/148606 , vital:38754 , https://doi.org/10.1016/j.sajb.2020.04.019
Description: Brazilian pepper (Schinus terebinthifolia) is a tree native to subtropical South America that was introduced into South Africa in the early 1900s as an ornamental plant. The tree has since escaped cultivation and has invaded ruderal and pristine habitats along the eastern coast of South Africa. Brazilian Pepper is also one of the most problematic invasive alien plants in Florida, USA. We modelled the climatically suitable area for this species in South Africa using MaxEnt, with five distinct datasets: incorporating both the native and the invaded range of the species, as well as different backgrounds.
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Date Issued: 2020

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Climate responsive innovation within the agricultural curriculum and learning system

- van Staden, Wilma

Authors: van Staden, Wilma
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/389744 , vital:68479 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/186598"
Description: The purpose of this paper is to outline the climate responsive innovation process within the agricultural innovation system of the North West Province, South Africa. The focus was on the embedded curriculum and learning activity system and its responses to social-ecological and earth system changes influenced by climate change. It outlines the barriers and processes hampering curriculum and learning innovations towards climate-smart responsiveness, and also examines the processes required to initiate micro and macro innovations. This paper focusses on how actors within the system can initiate curriculum innovation and climate responsiveness through micro innovations when supported and how this can lead to macro innovations. The system experienced various barriers during the innovation process and overcame many challenges during the journey towards climate-smart responsiveness through the identification of contradictions within the system, developing tools to assist in the transitioning process and expansion in the social-spatial dimension by establishing a learning network within the surrounding communities. The research indicated that the catalysing of the curriculum and learning system required specific tools, time and the understanding of the importance of micro-level innovation.
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Date Issued: 2020

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Clinically established biodegradable long acting injectables

- Nkanga, Christian I, Fisch, Andreas, Rad-Malkshahi, Mazda, Romic, Marieta D, Kittel, Birgit, Ullrich, Thomas, Wang, Jing, Krause, Rui W M, Adler, Sabine, Lammers, Twan, Hennink, Wim E, Ramazani, Farshad

Authors: Nkanga, Christian I , Fisch, Andreas , Rad-Malkshahi, Mazda , Romic, Marieta D , Kittel, Birgit , Ullrich, Thomas , Wang, Jing , Krause, Rui W M , Adler, Sabine , Lammers, Twan , Hennink, Wim E , Ramazani, Farshad
Date: 2020
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/193386 , vital:45327 , xlink:href="https://doi.org/10.1016/j.addr.2020.11.008"
Description: Long acting injectable formulations have been developed to sustain the action of drugs in the body over desired periods of time. These delivery platforms have been utilized for both systemic and local drug delivery applications. This review gives an overview of long acting injectable systems that are currently in clinical use. These products are categorized in three different groups: biodegradable polymeric systems, including microparticles and implants; micro and nanocrystal suspensions and oil-based formulations. Furthermore, the applications of these drug delivery platforms for the management of various chronic diseases are summarized. Finally, this review addresses industrial challenges regarding the development of long acting injectable formulations.
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Date Issued: 2020

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Co-loading of isoniazid-grafted phthalocyanine-in-cyclodextrin and rifampicin in crude soybean lecithin liposomes: Formulation, spectroscopic and biological characterization

- Nkanga, Christian I, Roth, Michael, Walker, Roderick B, Noundou, Xavier S, Krause, Rui W M

Authors: Nkanga, Christian I , Roth, Michael , 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/10962/183481 , vital:43999 , xlink:href="https://doi.org/10.1166/jbn.2020.2880"
Description: An inclusion complex of isoniazid-grafted phthalocyanine with gamma-cyclodextrin (Complex) was co-encapsulated with rifampicin (RIF) in crude soybean lecithin liposomes using a heating method. The encapsulation efficiency (%EE) of the Complex-RIF co-loaded liposomes (Rif-Complex-Lips) was determined using UV-Vis spectrophotometry. Rif-Complex-Lips formulations were evaluated using dynamic light scattering, transmission electron microscopy (TEM), 1H-NMR, absorption and emission spectroscopy. Dialysis was used for drug release study in two different media, pH 6.4 and 7.4. HeLa cells were used to assess potential cytotoxicity, and the uptake by lung fibroblasts and epithelial cells was investigated using fluorescence microscopy. The particle size and Zeta potential of Rif-Complex-Lips were approximately 594 nm and –50 mV. Spectroscopic analyses demonstrated molecular distribution of the cargo within the lipid core, and encapsulation efficiency of 58% for Complex and 86% for RIF. TEM analysis unveiled the existence of spherical nanoparticles in our samples, indicating the presence of liposomes. Rif-Complex-Lips exhibited much higher release rates for both INH and RIF at pH 6.4 compared to those tested at pH 7.4. In addition, there was no cytotoxicity on HeLa cells, but remarkable Rif-Complex-Lips internalization by peripheral lung fibroblasts and epithelial cells. Hence, Rif-Complex-Lips are promising vehicles for intracellular delivery of antimicrobial drugs.
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Date Issued: 2020

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