Showing items 2441 - 2460 of 4139

Your selections:

Temperature tolerance and humidity requirements of select entomopathogenic fungal isolates for future use in citrus IPM programmes

  • Authors: Acheampong, M A , Coombes, Candice A , Moore, Sean D , Hill, Martin P
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/419399 , vital:71641 , xlink:href="https://doi.org/10.1016/j.jip.2020.107436"
  • Description: Several isolates of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitacae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitacae) have been investigated as possible microbial control agents of key citrus pests in South Africa. Although laboratory results have been promising, field trials against foliar pests have shown limited success. These findings highlighted the need to investigate other biological attributes of these fungal isolates besides virulence in order to select candidates that may be better suited for the foliar environment. Thus, this study investigated the influence of temperature on the in vitro growth of seven indigenous local isolates and the humidity requirements necessary to promote successful infection, in comparison with two commercial isolates (B. bassiana PPRI 5339 and M. anisopliae ICIPE 69). All the fungal isolates grew across a range of temperatures (8–34 °C) and optimally between 26 and 28 °C. Similarly, fungal infection of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) fifth instars occurred across a range of humidity levels (12%, 43%, 75%, 98%) regardless of fungal concentration, although external sporulation was restricted to treatments exposed to 98% relative humidity. It was concluded that neither temperature nor humidity, when considered alone, is likely to significantly influence the efficacy of any of the isolates in the field, given that they are active within temperature and humidity ranges experienced in South African citrus orchards.
  • Full Text:
  • Date Issued: 2020

The association between HIV tri-therapy with the development of Type-2 Diabetes Mellitus in a rural South African district: A case-control study

  • Authors: Bam, Nokwanda E , Mabunda, Sikhumbuzo A , Ntsaba, Jafta , Apalata, Teke , Monatshila, Sibusisu C , Chitha, Wesile
  • Date: 2020
  • Subjects: Type 2 diabetes , AIDS (Disease) , Rural health
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/11260/4008 , vital:43983 , https://doi.org/10.1371/journal.pone.0244067
  • Description: Combination antiretroviral drugs(cARVs)prolong patients’ lives but are unfortunately thought to increase complications related to metabolic disorders including type-2 Diabetes Mellitus(DM).We sought to confirm the association of cARVs with type-2DM and ascertain the extent of this association in a rural South African setting. A case-control study of 177 (33.33%) cases with HIV/AIDS and type-2 DM were selected and compared with 354 (66.67%) non-DM HIV/AIDS unmatched controls from a rural district of South Africa’s third most populous province (Eastern Cape). Cases were identified from community health centres using the district health information system, and controls were identified using simple random sampling from the same health facilities. Odds Ratios (OR), together with 95% confidence intervals, were calculated for all the univariable and multivariable logistic analyses. This study found that cARVs significantly increased the occurrence of type-2 DM among HIV patients. Patients on protease inhibitors (PIs) were at least 21 times significantly more likely to be diabetic than those on the fixed dose combination (FDC); those on stavudine (D4T) and zidovudine (AZT) were 2.45 times and 9.44 times respectively more likely to be diabetic than those on FDC. The odds of diabetes increased by more than three-folds for those who had been on antiretroviral drugs for more than 6 years.
  • Full Text:
  • Date Issued: 2020

The crystal structure of 2-oxo-2H-chromen-4-yl acetate, C11H8O4

  • Authors: Hulushe, Siya T , Manyeruke, Meloddy H , Hosten, Eric C , Kaye, Perry , Watkins, Gareth M
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/194048 , vital:45418 , xlink:href="https://doi.org/10.1515/ncrs-2019-0698"
  • Description: C11H8O4, monoclinic, P21/c (no. 14), a = 4.5947(2) Å, b = 10.5414(3) Å, c = 19.1611(7) Å, β = 94.084(2)°, V = 925.70(6) Å3, Z = 4, Rgt(F) = 0.0376, wRref(F 2) = 0.1109,T = 200(2) K.CCDC no.: 1906383
  • Full Text:
  • Date Issued: 2020

The crystal structure of 2-oxo-2H-chromen-4-yl acetate, C11H8O4

  • Authors: Hulushe, Siya T , Manyeruke, Meloddy H , Hosten, Eric C , Kaye, Perry , Watkins, Gareth M , Krause, Rui W M
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/193442 , vital:45332 , xlink:href="https://doi.org/10.1515/ncrs-2019-0698"
  • Description: C11H8O4, monoclinic, P21/c (no. 14), a = 4.5947(2) Å, b = 10.5414(3) Å, c = 19.1611(7) Å, β = 94.084(2)°, V = 925.70(6) Å3, Z = 4, Rgt(F) = 0.0376, wRref(F 2) = 0.1109,T = 200(2) K.CCDC no.: 1906383
  • Full Text:
  • Date Issued: 2020

The effects of asymmetry in combination with reduced graphene oxide nanosheets on hydrazine electrocatalytic detection on cobalt phthalocyanines

  • Authors: Mpeta, Lekhetho S , Sen, Pinar , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186023 , vital:44456 , xlink:href="https://doi.org/10.1002/elan.202060094"
  • Description: New symmetric {tetrakis [4-(4-(5-chloro-1Hbenzo[d]imidazol-2-yl) phenoxy phthalocyaninato] Co (II) (CoTPc)} and low symmetry {tris tert butyl phenoxy mono [4-(4-(5-chloro-1H-benzo[d]imidazol-2-yl) phenoxy phthalocyaninato]} Co (II) (CoMPc) were successfully synthesised and combined with reduced graphene oxide nanosheets (rGONS) for electrocatalytic detection of hydrazine. Prior to electrocatalysis, the probes were characterised using cyclic voltammetry and electrochemical impedance spectroscopy. Chronoamperometry was used to determine catalytic rate constant and the limit of detection (LOD). CoMPc-rGONS gave catalytic rate constant and LOD of 1.37×106 M 1 s 1 and 0.82 μM respectively, rendering it a more suitable probe for hydrazine, due to low symmetry.
  • Full Text:
  • Date Issued: 2020

The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate creams

  • Authors: Fauzee, Ayesha F B , Walker, Roderick B
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/183275 , vital:43937 , xlink:href="https://doi.org/10.1080/23311916.2020.1804713"
  • Description: The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate (CP) cream formulations was investigated using a Central Composite Design of Experiments. Thirty batches of cream were manufactured and the formulation variables assessed were % v/v propylene glycol, % w/w Gelot® 64, cetostearyl alcohol and glyceryl monostearate content. The responses monitored included viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released at 72 hours. The responses were compared to those of a reference product, Dermovate® cream. ANOVA analysis revealed that viscosity, spreadability, and % CP released at 72 hours were significant formulation responses (p more than 0.05). Cetostearyl alcohol had the greatest impact on quality of pilot scale products. An increase in cetostearyl alcohol resulted in an increase in viscosity, a decrease in spreadability, and a decrease in % CP released at 72 hours. The optimized pilot scale CP formulation contained 46% v/v propylene glycol, 8.6% w/w cetostearyl alcohol, 10.5% w/w glyceryl monostearate, and 3.8% w/w Gelot® 64. The resultant viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released were 44633cP, 24.91cm2, 101.23 %, 76.98 g/cm2, 198.23 µS/cm, and 50.23%. The addition of cetostearyl alcohol and Gelot® 64 is critical for establishing a soft formulation that leads to the formation of a mixed crystal bilayer network of high viscosity. The formation of a separate crystalline lipophilic network usually occurs in semi-solid formulations that contain high concentrations of emulsifier, leading to an increase in shear stress and greater physicochemical stability of the formulation. The use of experimental design approaches to formulation development activities, permit evaluation of multiple factors simultaneously, reducing the time and costs associated with product development activities, whilst identifying a composition design space and ensuring stable and effective dosage forms are produced.
  • Full Text:
  • Date Issued: 2020

The impact of HIV knowledge and attitudes on HIV testing acceptance among patients in an emergency department in the Eastern Cape, South Africa

  • Authors: Ryan, Sofia , Hahn, Elizabeth , Rao, Aditi , Mwinnyaa, George , Black, John , Nyanisa, Yandisa , Quinn, Thomas C , Hansoti, Bhakti , Maharaj, Roshen , Mvandaba, Nomzamo
  • Date: 2020
  • Subjects: HIV testing , Emergency departments
  • Language: English
  • Type: article , text
  • Identifier: http://hdl.handle.net/11260/4473 , vital:44123 , https://doi.org/10.1186/s12889-020-09170-x
  • Description: Transmission of HIV in South Africa continues to be high due to a large proportion of individuals living with undiagnosed HIV. Uptake of HIV testing is influenced by a multitude of factors including the patient’s knowledge and beliefs about HIV. Methods: This study sought to quantify the impact of knowledge and attitudes on HIV testing acceptance in an emergency department by co-administering a validated HIV knowledge and attitudes survey to patients who were subsequently offered HIV testing. During the study period 223 patients were interviewed and offered HIV testing. Individuals reporting more negative overall attitudes (p = 0.006), higher levels of stigma to HIV testing, and individuals who believed their test was confidential were more likely to accept an HIV test. Interventions focused on improving patient perceptions around testing confidentiality will likely have the greatest impact on testing acceptance in the emergency department.
  • Full Text:
  • Date Issued: 2020

The influence of citrus orchard age on the ecology of entomopathogenic fungi and nematodes

  • Authors: Albertyn ,Sonnica , Moore, Sean D , Marsberg, Tamryn , Coombes, Candice A , Hill, Martin P
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/417545 , vital:71462 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
  • Description: A three-year survey of the ecology of entomopathogenic nematodes (EPN) and entomopathogenic fungi (EPF) was undertaken on soils from citrus orchards of different ages to determine the influence of orchard age on the ecology of entomopathogenic fungi and nematodes. The influence of mulch and irrigation method on the occurrence of EPN and EPF was also determined. Most of the isolates recovered (n = 810) were Beauveria sp. (87.88% of all isolates), followed by Metarhizium sp. (11.87% of all isolates). Only 0.24% of soil samples collected during this study tested positive for EPN. All EPN isolates recovered were Heterorhabditis bacteriophora. No significant differences in EPF occurrence were recorded between orchards under drip and micro-sprinkler irrigation. EPF occurrence was significantly lower (P = 0.016) in orchards covered by mulch (31.85% ± 2.07% occurrence) than in orchards with no covering (38.57% ± 1.57% occurrence). EPF occurrence of 40.33 ± 2.13% was highest in non-bearing orchards, followed by mature orchards (nine years or older) (36.76 ± 2.05% of samples) with the lowest EPF occurrence of 25.30 ± 2.02% reported in juvenile orchards (four to eight years old). Juvenile orchards sustain significantly less EPF than mature and non-bearing orchards because of the combined negative impact of less favourable environmental conditions (lower shade density) and fungicide applications.
  • Full Text:
  • Date Issued: 2020

The Integration of Personally-owned Information and Communication Technologies (PICTs) for Teaching and Learning in Resource-Constrained Higher Education Environments – The Case of a Nigerian University

  • Authors: Lewis, Oláñrewájú Olúrotimi
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/163582 , vital:41050 , doi:10.21504/10962/163582
  • Description: Thesis (PhD)--Rhodes University, Faculty of Commerce, Information Systems, 2020
  • Full Text:
  • Date Issued: 2020

The invasive grass genus Nassella in South Africa: A synthesis

  • Authors: Mapaura Anthony , Canavan, Kim N , Richardson, David M , Clark, Vincent R , Steenhuisen, Sandy-Lynn
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/424842 , vital:72188 , xlink:href="https://doi.org/10.1016/j.sajb.2020.08.031"
  • Description: Three species of Nassella have naturalized in South Africa. Nassella trichotoma and N. tenuissima are declared weeds under category 1b of the National Environmental Management: Biodiversity Act (NEM:BA) and occur mainly in the montane grasslands of the Western and Eastern Cape provinces. Nassella neesiana is not listed in NEM:BA but is naturalized in the Eastern Cape, Western Cape and Free State provinces. Research conducted in the 1970s and 1980s led to vigorous government-funded awareness and control campaigns which ended in 2000. No research on Nassella distribution or control has been undertaken since then. Despite this hiatus, Nassella remains a dangerous genus in southern Africa, given the serious impacts of these species in similar social-ecological systems in Australia and New Zealand. This paper presents a synthesis of available information about Nassella invasions in South Africa and identifies research gaps. It specifically addresses these questions: What identification issues exist? What is the current spatial distribution of Nassella? What is the autecology of the genus? What are the social-ecological impacts of Nassella? What control measures are currently applied and what are their strengths and limitations? What do we know about Nassella distribution and its response to climate change? This paper highlights many knowledge gaps about Nassella, such as the species’ current distribution range, field identification and detection difficulties, and the uncoordinated control efforts that require urgent research to inform an effective management response.
  • Full Text:
  • Date Issued: 2020

The modulation of the photophysical and photodynamic therapy activities of a phthalocyanine by detonation nanodiamonds: Comparison with graphene quantum dots and carbon nanodots

  • Authors: Matshitse, Refilwe , Managa, Muthumuni , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186690 , vital:44525 , xlink:href="https://doi.org/10.1016/j.diamond.2019.107617"
  • Description: A positively charged phthalocyanine (2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ)) was non-covalently linked to carbon based nanoparticles: detonation nanodiamonds (DNDs), carbon dots (CDs) and graphene quantum dots (GQDs) to form nanosembles of DNDs-ZnTPPcQ, GQDs-ZnTPPcQ and CDs-ZnTPPcQ, respectively. Irrespective of its small size and the least number of Pcs (41.67 μg loading per milligram of DNDs), DNDs-ZnTPPcQ gave the highest singlet oxygen quantum yield (0.62) in dimethyl sulfoxide compared to the rest of the conjugates. This resulted in superior PDT activity against MCF7 breast cancer lines, with the lowest cell viability of 28% compared to ZnTPPcQ-CDs and ZnTPPcQ-GQDs at 30.1 ± 0.02% and 31.4 ± 0.23%, respectively.
  • Full Text:
  • Date Issued: 2020

The novobiocin-induced turnover of fibronectin via low density lipoprotein receptor-related protein 1 alters matrix morphology with physiological consequences on cell growth and migration

  • Authors: Boёl, Natasha Marie-Eraine
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/114778 , vital:34034 , 10.21504/10962/114778
  • Description: Fibronectin (FN), an extracellular matrix protein, is secreted as a soluble dimer which is assembled into an insoluble extracellular matrix. The dynamics of FN matrix assembly and degradation play a large role in cell migration and invasion thereby contributing to the metastatic potential of cancer cells. Previous studies have shown the direct binding of Heat Shock Protein 90 kDa (Hsp90) and FN in vitro, and that inhibition of Hsp90 with novobiocin (NOV) caused internalisation of the FN matrix. Low density lipoprotein receptor-related protein 1 (LRP1) is a ubiquitous receptor known to bind both Hsp90 and FN. Using an LRP1 expressing Hs578T breast cancer cell line and an isogenic mouse embryonic fibroblast (MEF) model system of differential LRP1 expression we demonstrate that LRP1 is involved in turnover of FN in response to C-terminal Hsp90 inhibition. The first objective of this study was to identify the mechanism of NOV-induced LRP1-mediated FN turnover. Our data show that NOV-mediated FN turnover via LRP1 did not require the activity of matrix metalloproteinases (MMPs), which play an important role in processing and degradation of the extracellular matrix and FN. In addition, the levels of the main FN receptor responsible for its extracellular assembly, β1-integrin, did not change in response to NOV. LRP1 is known to undergo regulated intramembrane proteolysis (RIP) which generates smaller fragments that may translocate to the nucleus and modulate gene transcription. Using inhibitors of LRP1 cleavage and nuclear fractionation we determined that LRP1 processing was not required for the NOV-induced FN response suggesting that a mechanism unrelated to LRP1 RIP is involved. A possible mechanism may be in altered Hsp90-LRP1 cell signalling as we observed disruption of the FN-Hsp90-LRP1 complex at the cell surface in NOV treated cells. How this affects downstream eHsp90-LRP1 signalling is still to be determined but may be related to a significant increase in phospho-AKT and loss of phospho-ERK upon NOV-treatment; two key signalling proteins involved in FN matrix regulation and which are downstream of LRP1 signalling. The second objective of this study was to determine the physiological consequences associated with FN turnover in response to NOV treatment. Using migration assays we demonstrated that levels of insoluble matrix-associated FN and FN concentration are not solely responsible for migratory capacity of cells on decellularized extracellular matrices, but rather that structural composition and integrity of the matrix plays a bigger role. Using confocal and scanning electron microscopy, we identified NOV treated matrices to be flatter, less mature and contain thicker, rope-like FN fibrils to which cells adhered better but were generally less proliferative. Comparatively, cells adhered less to the more mature and 3-dimensional untreated matrices but exhibited increased spreading and cell growth, which may in part be due to the thinner fibrils and web-like matrix. In summary, this study substantiates the role of LRP1 in NOV-mediated FN turnover, and provides new insights into the possible mechanisms of the Hsp90-LRP1 mediated loss of FN matrix. This is the first study to demonstrate some of the functional consequences related to FN turnover by NOV at the ECM level. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
  • Full Text: false
  • Date Issued: 2020

The photodynamic antimicrobial chemotherapy of Stapphylococcus aureus using an asymmetrical zinc phthalocyanine conjugated to silver and iron oxide based nanoparticles

  • Authors: Mapukata, Sivuyisiwe , Nwahara, Nnamdi , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186078 , vital:44461 , xlink:href="https://doi.org/10.1016/j.jphotochem.2020.112813"
  • Description: The synthesis and characterisation of asymmetrical zinc(II) 2(3)-mono-isophthalic acid-9(10),16(17),23 (24)-tri (tert-butylphenoxy) phthalocyanine (complex 4) are reported. The phthalocyanine is conjugated to cysteamine capped silver nanoparticles (Cys-Ag NPs), amine functionalised iron oxide magnetic nanoparticles (NH2-Fe3O4 NPs) and a core-shell composite of the two (Cys-Fe3O4@Ag) via amide bonds. The photo-physico-chemical properties of complex 4 and its respective nanoconjugates (4-Ag, 4-Fe3O4 NPs and 4-Fe3O4@Ag NPs) are also reported. The nanoconjugates showed improved triplet and singlet oxygen quantum yields compared to complex 4. The antibacterial activity of complex 4 and its nanoconjugates were also evaluated on S. aureus wherein their activity was found to be mainly visible light driven with the best catalyst being 4-Fe3O4@Ag. The work therefore demonstrates the feasibility of phthalocyanine-nanoparticle based compounds as potential agents in real life antibacterial treatment
  • Full Text:
  • Date Issued: 2020

The photophysicochemical properties and photodynamic therapy activity of In and Zn phthalocyanines when incorporated into individual or mixed Pluronic® micelles

  • Authors: Motloung, Banele M , Babu, Balaji , Prinsloo, Earl , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186124 , vital:44465 , xlink:href="https://doi.org/10.1016/j.poly.2020.114683"
  • Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of tetra-pyridyloxy (1,2) and benzothiazole (3, 4) substituted indium (III) (1,3) and zinc (2, 4) phthalocyanines (Pcs) and their incorporation into Pluronic® F127 and Pluronic L121/F127 mixed micelles (the latter for 3 and 4 only) are presented in this study. The InPcs exhibited higher singlet oxygen (ΦΔ) at 0.76 and 0.68 compared to the ZnPc’s at 0.47 and 0.44 in dimethyl sulfoxide. The ΦΔ values in the presence of Pluronic® F127 and in water, were 0.39 and 0.42 for InPcs and 0.23 and 0.37 for ZnPc. The ΦΔ values in the presence of Pluronic F127/L121 mixed micelles for complex 3 and 4 were 0.51 and 0.29 in water. The Kp was determined using the water and octanol system. InPcs had larger Kp values suggesting that they are more likely to be taken up by the cancer cells hence they showed better PDT activity
  • Full Text:
  • Date Issued: 2020

The potential for biological control on cryptic plant invasions

  • Authors: Canavan, Kim , Canavan, Susan , Harms, Nathan E , Lambertini, Carla , Paterson, Iain D , Thum, Ryan
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/423562 , vital:72072 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104243"
  • Description: Cryptic invasions can be defined as ‘the occurrence of an invasive species or genotype that was not previously recognised as alien in origin or not distinguished from other aliens’. Such invasions can result in negative impacts on the recipient ecosystems and disturb the evolutionary history of native plant populations. Many cryptic invasions have become so problematic that there is a need to implement control measures. This paper explores the potential for biological control to be implemented as a means of managing cryptic invasions. Firstly, the paper defines the different forms of cryptic invasion, differentiating between interspecific and intraspecific invasions; this hierarchy influences how to detect, study and ultimately implement biological control when cryptic invasions occur. Secondly, unique challenges associated with biological control programmes for cryptic invasions are addressed, including: the need for intraspecific level host specificity in agents, the occurrence of hybridisation between native species/lineages and the target weed, the role of enemy release in cryptic invasions in the presence of closely related native plant species/lineages, and a review of potential stakeholder conflicts of interest and legislation. Biological control of cryptic invasions has been shown to be possible, however the process will be more difficult and complex than controlling traditional targets and will likely take up more time and resources. If these challenges are overcome, then biological control programmes against cryptic invasions should be able to proceed and maintain the same standards as traditional biological control programmes.
  • Full Text:
  • Date Issued: 2020

The relationship between childhood trauma and schizophrenia in the Genomics of Schizophrenia in the Xhosa people (SAX) study in South Africa

  • Authors: Mall, Sumaya , Platt, Jonathan M , Temmingh, Henk , Musenge, Eustasius , Campbell, Megan , Susser, Ezra , Stein, Dan J
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/302567 , vital:58208 , xlink:href="https://doi.org/10.1017/S0033291719001703"
  • Description: Background. Evidence from high-income countries suggests that childhood trauma is associated with schizophrenia. Studies of childhood trauma and schizophrenia in low and middle income (LMIC) countries are limited. This study examined the prevalence of childhood traumatic experiences among cases and controls and the relationship between specific and cumulative childhood traumatic experiences and schizophrenia in a sample in South Africa. Methods. Data were from the Genomics of Schizophrenia in the South African Xhosa people study. Cases with schizophrenia and matched controls were recruited from provincial hospitals and clinics in the Western and Eastern Cape regions in South Africa. Childhood traumatic experiences were measured using the Childhood Trauma Questionnaire (CTQ). Adjusted logistic regression models estimated associations between individual and cumulative childhood traumatic experiences and schizophrenia. Results. Traumatic experiences were more prevalent among cases than controls. The odds of schizophrenia were 2.44 times higher among those who experienced any trauma than those who reported no traumatic experiences (95% CI 1.77–3.37). The odds of schizophrenia were elevated among those who experienced physical/emotional abuse (OR 1.59, CI 1.28–1.97), neglect (OR 1.39, CI 1.16–1.68), and sexual abuse (OR 1.22, CI 1.03–1.45) compared to those who did not. Cumulative physical/emotional abuse and neglect experiences increased the odds of schizophrenia as a dose–response relationship. Conclusion. Childhood trauma is common in this population. Among many other benefits, interventions to prevent childhood trauma may contribute to a decreasing occurrence of schizophrenia.
  • Full Text:
  • Date Issued: 2020

The Rise of the Executive Dean and the Slide into Managerialism

  • Authors: McKenna, Sioux
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/187139 , vital:44573 , xlink:href="http://dx.doi.org/10.17159/2221-4070/2020/v9i0a6"
  • Description: Universities have long been characterised by hierarchical and paternalistic management structures and institutional cultures. Change is therefore to be welcomed but, in contexts where social change is urgently needed, it is possible to mistake a change in any direction as being worthwhile. Around the world, recent shifts in university leadership and management have been towards managerialist approaches that work against a shared responsibility for the academic project. Accusations of managerialism often refer to a general sense that institutions are becoming bureaucratic, or that it is the logic of the market that drives decision-making. But beyond vague complaints, these accusations fail to identify the exact processes whereby managerialism takes hold of the institution. This article hones in on one specific example of institutional change in order to argue that it is implicated in the move towards managerialism: most universities in South Africa have changed from having elected deans, selected by faculty, to executive deans, appointed by selection committee. Crudely distinguished, it can be said that elected deans represent the interests of their faculty up into various institutional structures whereas executive deans are tasked with implementing the decisions of top management down into faculty. This paper tracks the differences between the two forms of deanship through reflections on discussions about such a change at one South African institution, Rhodes University. It analyses the literature to argue that we do not have to choose between patriarchal management and compliance-based managerialism. Instead, we can choose shared responsibility for the academic project.
  • Full Text:
  • Date Issued: 2020

The Role of HSP70/HSP90 Organizing Protein (Hop) in the Heat Shock Factor 1 (HSF1)-mediated Stress Response

  • Authors: Chakraborty, Abantika
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/163204 , vital:41018 , doi:10.21504/10962/163204
  • Description: Molecular chaperones regulate cellular proteostasis. They control protein conformation and prevent misfolding and aggregation under both normal and stressful environments, ultimately resulting in cell survival. The project aimed to understand the role of the HSP70 – HSP90 Organizing Protein (Hop/STIP1) in the survival of stressed cells and the function of the stress-responsive transcription factor, Heat Shock Factor 1 (HSF1). HSF1 protein levels were significantly reduced in Hop-depleted HEK293T cells compared to controls by ELISA, western blot, and mass spectrometry. HSF1 transcriptional activity at the HSP70 promoter, and binding of a biotinylated HSE oligonucleotide under basal conditions were significantly reduced, consistent with the reduced levels of HSF1. In response to heat shock, HSF1 levels in Hop-depleted cells increased to that of controls, but there was still significantly lowerHSF1 transcriptional activity and HSE binding. Hop-depleted HEK293T cells were more sensitive than controls to the HSF1 inhibitor KRIBB11 and showed reduced short-term and long-term proliferation. Unlike the HSP90 inhibitor 17-DMAG, which had no effect, the HSP70 inhibitor JG98, further decreased the levels of HSF1 in Hop-depleted cells, suggesting a role for HSP70 in the Hop-mediated effects. There was punctate nuclear staining for HSF1 in Hop-depleted cells under both basal and heat shock conditions, as well as reduced nuclear localization and increased cytoplasmic accumulation of HSF1 in response to heat shock. Hop and HSF1 colocalized in cells, and HSF1 could be isolated in complex with Hop and HSP70. Loss of Hop reduced HSF1 in HSP70complexes but did not affect HSF1 abundance in HSP90 complexes. Hop-depleted cells showed reduced short-term and long-term survival compared to controls, an effect that was potentiated by the JG98 HSP70 inhibitor. Taken together, these data suggest that Hop regulation of HSF1activity is via a mechanism involving reductions in HSP70 interaction, as well as reduced nuclear localization, and DNA binding, and is consistent with reduced cellular fitness under basal and stress conditions. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
  • Full Text:
  • Date Issued: 2020

The role of primary schools in promoting democratic values of justice, equality and liberty in pupils: a study of Shamva district, Zimbabwe

  • Authors: Dzavo, Joseph
  • Date: 2020
  • Subjects: Democracy and education , Education -- Zimbabwe -- History , Education, Primary -- Curricula
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10353/27297 , vital:66696
  • Description: This study examines the role of primary schools in promoting democratic values of justice, equality and liberty in pupils in Shamva District, Zimbabwe. The study was necessitated by the continual abuse of democratic values by school leavers in the district before, during and after elections. Such continued abuses make one wonder if schools really inculcate democratic values of justice, equality and liberty in their pupilsas enshrined in the curriculum. Using a qualitative approach, the study is located within the interpretivist research paradigm. A case study design was adopted and three primary schools in Shamva District were purposively and conveniently selected for this study. The sample comprised three 3 primary schools heads, three 3 deputy heads, nine 9 teachers, five 5 school leavers and fifteen 15 prefects aged between 10 and 15 years old. Data was generated through semi-structured face-to-face interviews, focus group interviews and document analysis. The findings of the study revealed that schools had challenges in inculcating democratic values of justice, equality and liberty in learners. The challenges included difficulties in interpreting the syllabi on inculcation of democratic values of justice, equality and liberty in learners; democratic values being viewed as sensitive content usually misconstrued to be favouring certain political agendas by community members; and the lack of a clear cut democratic values curriculum framework to guide teachers on teaching democratic values of justice, equality and liberty. Some of the recommendations were that teachers should be protected by legal instruments like policies to enable them to freely teach sensitive content. Teachers also need empowerment in syllabus interpretation on the inculcation of democratic values to be able to effectively promote the teaching of democratic values of justice, equality and liberty. , Thesis (PhD) -- Faculty of Education, 2020
  • Full Text:
  • Date Issued: 2020

The role of the Hop co-chaperone in the formation of Hsp90 complexes: chaperone link to glycolysis

  • Authors: Maharaj, Shantal
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/163593 , vital:41051 , doi:10.21504/10962/163593
  • Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
  • Full Text:
  • Date Issued: 2020
  • Disclaimer
  • Privacy
  • Copyright
  • Contact