1834 research outputs found
Sort by
Focus areas of cardiovascular medical device research in South Africa
No full textWe investigated the focus of cardiovascular medical device research in South Africa over the 15-year period 2000 - 2014. Information drawn from journal articles was used for the analysis, with attention to articles describing a contribution to the development of a cardiovascular medical device, or a new application of an existing device. The findings suggest that research has focused on diagnostic and monitoring as well as prosthetic cardiovascular medical devices, with specific emphasis on vascular and valvular heart diseasesNational Research Foundation (South Africa
Rhythmic trajectory design and control for rehabilitative walking in patients with lower limb disorder
No full textWearable robotic systems have been a mechanism which clearly drives the motive of bringing back paraplegics back on their feet as well as executing difficult task beyond human ability. The purpose of this research study is to design and investigate the efficacy of rehabilitative walking in patients with lower limb disorders using oscillators which may commonly be referred to as central pattern generators (CPGs). In order to achieve this, a rhythmic trajectory is designed using Van der Pol oscillators. This rhythmic trajectory commensurates with the movement pattern of the hips and knees for a normal walking gait of humans. The dynamical model of a five-link biped exoskeletal device having four actuated joints is computed with regard to the wearer using Lagrangian principles in the sagittal plane. A feedback linearization control technique is therefore utilized for tracking the rhythmic trajectory to achieve a proper following of the human walking gait. Matlab/Simulink is used to validate this proposed strategy in the presence of uncertainties with a view to implementing it practically in the laboratory with human in the loop. Results show that humans with the aid of the exoskeleton device will possess the ability to track this rhythmic trajectory representing the hip and knee joint movements. The controller proved robust enough against disturbance.National Research Foundation (South Africa
Testing epidemiological functional groups as predictors of avian haemosporidia patterns in southern Africa
No full textUnderstanding the dynamics of multihost parasites and the roles of different host species in parasite epidemiology requires consideration of the whole animal community. Host communities may be composed of hundreds of interacting species, making it necessary to simplify the problem. One approach to summarizing the host community in a way that is relevant to the epidemiology of the parasite is to group host species into epidemiological functional groups (EpiFGs). We used EpiFGs to test our understanding of avian malaria (Plasmodium and Haemoproteus) dynamics in four communities of wetland‐associated birds in southern Africa. Bird counts and captures were undertaken every 2–4 months over 2 yr and malaria was diagnosed by nested PCR. One hundred and seventy‐six bird species were allocated to a set of EpiFGs according to their assumed roles in introducing and maintaining the parasite in the system. Roles were quantified as relative risks from avian foraging, roosting, and movement ecology and assumed interaction with vector species. We compared our estimated a priori risks to empirical data from 3414 captured birds from four sites and 3485 half‐hour point counts. After accounting for relative avian abundance, our risk estimates significantly correlated with the observed prevalence of Haemoproteus but not Plasmodium. Although avian roosting height (for both malarial genera) and movement ecology (for Plasmodium) separately influenced prevalence, host behavior alone was not sufficient to predict Plasmodiumpatterns in our communities. Host taxonomy and relative abundance were also important for this parasite. Although using EpiFGs enabled us to predict the infection patterns of only one genus of heamosporidia, our approach holds promise for examining the influence of host community composition on the transmission of vector‐borne parasites and identifying gaps in our understanding of host–parasite interactions.NRF-South Afric
Finance and auditing breakaway session
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 7th annual Research Administrators Workshop (RAW) from 4 to 6 October 2016 in Polokwane. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management
Research administrators workshop - report 2016
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 7th annual Research Administrators Workshop (RAW) from 4 to 6 October 2016 in Polokwane. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management
Enhancing research impact in Africa through strategic partnerships
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 7th annual Research Administrators Workshop (RAW) from 4 to 6 October 2016 in Polokwane. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management
RAW 2016 – the role of the DA
No full textThe Grants Management and Systems Administration (GMSA) Directorate hosted its 7th annual Research Administrators Workshop (RAW) from 4 to 6 October 2016 in Polokwane. The workshop aimed to bring together key stakeholders from universities and science councils across South Africa, including international delegates, to share experiences and best practices in research administration and management
Prising open the black box: the production of knowledge on the mental health ‘treatment gap’ in Africa
No full textIn this research I surface the epistemological assumptions underpinning thinking on the apparent high numbers of people with mental illness in Africa not receiving care, known as the ‘treatment gap’. I thus prise open the ‘black box’ of this knowledge, scrutinising its underlying meaning codes and capillaries of power.
I explore knowledge produced on the ‘treatment gap’ at three different sites: 1) Mental health research in Africa published over the last decade; 2) National mental health policies of 14 African countries; 3) Narratives of 28 psychiatrists all working in public mental health care provision in South Africa, Uganda, Ethiopia or Nigeria. For my analysis I develop a theoretical toolbox which draws on concepts from two broad and multidisciplinary fields, namely Science and Technology Studies (STS) and Postcolonial Studies.
What emerged was that knowledge on the ‘gap’ in mental health care is deeply inserted within the episteme of European Colonial Modernity, and thus saturated with Eurocentric tendencies. In particular, two paradigms are playing a fundamental role, those of evidence-based science (including biomedicine) and human rights. I destabilise the inevitability of these paradigms by putting them in historical perspective, and shedding light on the many questionable certainties and binary oppositions upon which they are based. I show how they have become the gatekeepers of knowledge, ultimately occluding ‘other’ ways of knowing which are based upon alternative epistemological codes. The somewhat singular voice of scholarly authority was, however, at times softened by certain quieter and more marginalised voices. These suggested avenues out of which more decolonised,
‘Africa-focused’ models of scholarship might potentially grow. To sum up, I surface particular tensions and hold them up to the light, with the hope of disturbing certain intellectual reflexes and creating a space for potential alternatives. Ultimately, this might help foster different sorts of conversations on the ‘treatment gap’ from those created by current seats of power.P&M Flanagan ScholarshipNational Research Foundation (South Africa)Oppenheimer Memorial Trus
Genomic resource development for the South African scallop, pecten sulcicostatus
No full textAlthough South Africa boasts a rich biodiversity, many South African species,
especially marine species, remain uncharacterised. Many of these species show
great potential for commercial use, in particular for the aquaculture of endemic
species for high-value, specialised markets. Only once these species have been
identified and genetically characterised can the feasibility of aquaculture be
evaluated.
‘Scallop’ refers to species of marine bivalve molluscs in the family Pectinidae,
although it may also refer to species in other closely related families within the
superfamily Pectinoidea. There are 29 scallop species in the waters surrounding
South Africa, and of these, Pecten sulcicostatus has been identified as a candidate
species for aquaculture. Non-destructive sampling is necessary for studies on
genetic fitness and population structure to not be hindered by the death of the study
individuals. DNA extraction methods using non-destructive sample tissue have not
been developed for scallops, therefore this study compared the use of various tissue
types in DNA extraction, allowing for the development of an effective non-destructive
DNA extraction method for P. sulcicostatus using tentacle tissue and mucus swabs.
This study also allowed for the development of an effective DNA extraction method
for use on dried or degraded tissue, which will, in turn, allow for the use of
opportunistic and historic samples in future studies on P. sulcicostatus.
Despite the potential commercial value of P. sulcicostatus, no genetic resources are
available for this endemic species. The development of genetic markers will assist in
future studies on the genetic composition of this species as well as the genetic
constitution of P. sulcicostatus populations along the South African coast – factors
which are important for the formulation of effective genetic management strategies.
This study therefore aimed to develop genetic markers for P. sulcicostatus and to
conduct preliminary analyses using these markers to demonstrate their usefulness
for future studies, which will assist in the establishment of a sustainable aquaculture
industry. This study allowed for the optimisation of a fragment of the 16S rRNA gene
which was successfully used to determine intra- and interspecific genetic diversity
and shed light on the evolutionary relationship of five Pecten species. A set of 10
microsatellite markers was developed for P. sulcicostatus using cross-species amplification from Pecten maximus, a sister species to P. sulcicostatus, with a
success rate of 50%. The set of microsatellite markers was successfully applied to
generate genetic diversity data, which, in future studies, could be used to evaluate
the extent of intra- and interpopulation genetic partitioning and variation. This study
also provided the first reduced genome sequences for P. sulcicostatus, with over 7.3
million reads. The use of two bioinformatic approaches aided in the identification of
55 putative microsatellite markers as well as 2 530 putative SNPs. Although currently
limited, this study marks the first step towards providing genetic information to assist
in the development of genetic management strategies within the context of
establishing a sustainable aquaculture industry for this endemic species. The genetic
resources developed in this study could be used in various downstream applications
such as genetic diversity assessment, population structure inference, linkage studies
as well as marker assisted selection. In future, the microsatellite markers and SNPs
developed in this study could also be continuously used to monitor genetic diversity
as the species is subjected to aquaculture.National Research Foundatio
Heterologous expression of cellulase genes in natural saccharomyces cerevisaie strains
No full textThe yeast Saccharomyces cerevisiae is regularly chosen for the heterologous production of
industrial and medically relevant proteins, due to its rapid growth rate, high cell density
fermentation capabilities, microbial safety and eukaryotic post-translational processing.
Identifying strains with superior secretion and production of recombinant proteins, whether for
pharmaceutical, agricultural or industrial processes, has the benefit of lowering production
costs. This holds true for second generation (2G) cellulosic bioethanol production, where high
titers of key cellulolytic enzymes are needed to break down complex lignocellulosic substrates.
While several secretion-enhancing strategies have been attempted in heterologous production
hosts, these strategies were limited by bottlenecks in the secretory pathway. Although protein
characteristics and host restrictions are likely to contribute to these bottlenecks, these
limitations are poorly understood.
Exploiting naturally occurring yeast variants has shown great potential to identifying strains
with varying fermentation profiles and tolerance to industrial stresses. The same variation is
expected in the secreted and total heterologous cellulolytic activity levels between natural
S. cerevisiae strains. Many natural yeast strains may not be suitable for direct industrial
fermentation, however industrially relevant traits could be transferred to industrial strains,
thereby creating a novel yeast strains with extra beneficial features. In this study, the potential
of natural S. cerevisiae strains with regards to superior cellulolytic activity levels, robustness
and other ideal characteristics for 2G cellulosic bioethanol production were evaluated.
Preliminary screening of thirty natural strains for the production of Saccharomycopsis
fibuligera Cel3A (S.f.Cel3A) activity demonstrated variation in secreted cellulase activity
levels, allowing us to select seven strains with promising phenotypes. After cellulase genes
were expressed on episomal and delta integrative plasmids in S .cerevisiae strains, the secreted
activity yields of episomally produced Trichoderma reesei Cel5A (T.r.Cel5A) and
Talaromyces emersonii Cel7A (T.e.Cel7A) were 3.5- and 3.7-fold higher in natural strain YI13
compared to reference strain S288c. However, no single strain had highest secreted activity for
all three enzymes, suggesting cell specific activity levels is dependent on the genetic
background of the host and properties of the protein. Nevertheless, YI13 was identified to be
highly tolerant to secretion and cell wall stresses (predicted to result in higher cell specific
activities).
Stellenbosch University https://scholar.sun.ac.za
iii
After evaluating other industrially relevant characteristics including growth vigour,
fermentation vigour and tolerance to industrial stressors, natural strains were identified to have
promising features for 2G cellulosic ethanol production. Variation in the fermentative
(YP-glucose and Avicel cellulose) profiles of S. cerevisiae strains are observed, with the natural
strains producing similar titers of ethanol (9.0 g/L) compared with the benchmark MH1000
strain in YP-glucose fermentation conditions. Multi-tolerance traits to industrial stresses were
demonstrated by the YI13 strain including high ethanol tolerance (10% w/v), high temperature
tolerance (37oC and 40oC), and tolerance to a cocktail of inhibitory compounds found in
lignocellulosic hydrolysates, suggesting that this strain has a balance between an effective
secretion pathway and robustness to withstand environmental conditions. These strains are a
significant step toward creating an efficient cellulase secreting yeast for 2G bioethanol
production.National Research Foundatio