Preformulation characterization and identification of excipients for nevirapine loaded niosomes
- Witika, Bwalya A, Walker, Roderick B
- Authors: Witika, Bwalya A , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183126 , vital:43914 , xlink:href="https://doi.org/10.1691/ph.2021.0137"
- Description: Nevirapine (NVP) is used for the management of HIV/AIDS but must be dosed frequently, exhibits unpredictable bioavailability and a side effect profile that includes hepato- and dermo-toxicity. Niosomes are a colloidal drug delivery system that may be used to overcome the low bioavailability, side effect profile and frequent dosing needed when using conventional drug delivery systems. The compatibility of NVP with sorbitan esters, polysorbate, cholesterol and dihexadecyl phosphate (DCP) was investigated using Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red Spectroscopy (FTIR) and X-ray Powder Diffraction (XRPD). Screening studies were undertaken to identify potential excipients that would produce niosomes with target critical quality attributes (CQA) viz, a particle size (PS) less than 1000 nm, a polydispersity index (PDI) less than 0.500 and an entrapment efficiency greater than 90%. The results revealed that sorbitan esters in combination with cholesterol and 5 μmol DCP produced niosomes with the best CQA and Zeta potential (ZP) less than -30 mV which suggests good stability of the niosomes on storage. Sorbitan esters produced the smallest niosomes of less than 400 nm diameter with a PDI less than 0.400 and an entrapment efficiency of more than 78% without cholesterol. The addition of cholesterol and DCP was essential to form niosomes with target CQA.
- Full Text:
- Authors: Witika, Bwalya A , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183126 , vital:43914 , xlink:href="https://doi.org/10.1691/ph.2021.0137"
- Description: Nevirapine (NVP) is used for the management of HIV/AIDS but must be dosed frequently, exhibits unpredictable bioavailability and a side effect profile that includes hepato- and dermo-toxicity. Niosomes are a colloidal drug delivery system that may be used to overcome the low bioavailability, side effect profile and frequent dosing needed when using conventional drug delivery systems. The compatibility of NVP with sorbitan esters, polysorbate, cholesterol and dihexadecyl phosphate (DCP) was investigated using Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Fourier Transform Infra-red Spectroscopy (FTIR) and X-ray Powder Diffraction (XRPD). Screening studies were undertaken to identify potential excipients that would produce niosomes with target critical quality attributes (CQA) viz, a particle size (PS) less than 1000 nm, a polydispersity index (PDI) less than 0.500 and an entrapment efficiency greater than 90%. The results revealed that sorbitan esters in combination with cholesterol and 5 μmol DCP produced niosomes with the best CQA and Zeta potential (ZP) less than -30 mV which suggests good stability of the niosomes on storage. Sorbitan esters produced the smallest niosomes of less than 400 nm diameter with a PDI less than 0.400 and an entrapment efficiency of more than 78% without cholesterol. The addition of cholesterol and DCP was essential to form niosomes with target CQA.
- Full Text:
Prevalence and clinical correlates of substance use disorders in South African Xhosa patients with schizophrenia
- Temmingh, Henk, Susser, Ezra, Mall, Sumaya, Campbell, Megan, Sibeko, Goodman, Stein, Dan J
- Authors: Temmingh, Henk , Susser, Ezra , Mall, Sumaya , Campbell, Megan , Sibeko, Goodman , Stein, Dan J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302509 , vital:58203 , xlink:href="https://doi.org/10.1007/s00127-020-01942-5"
- Description: Purpose: To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs. Methods: Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs. Results: In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Signifcant predictors of any SUD were younger age (41–55 vs. 21–30: OR=0.7, 95% CI=0.5–0.9), male sex (OR=8.6, 95% CI=5.1–14.6), inpatient status (OR=1.7, 95% CI=1.3–2.1), post-traumatic stress symptoms (OR=4.6, 95% CI=1.6–13.3), legal (OR=3.4, 95% CI=2.0–5.5) and economic problems (OR=1.4, 95% CI=1.0–2.0). Methamphetamine use disorders occurred signifcantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were signifcantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were signifcantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs. Conclusion: SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.
- Full Text:
- Authors: Temmingh, Henk , Susser, Ezra , Mall, Sumaya , Campbell, Megan , Sibeko, Goodman , Stein, Dan J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302509 , vital:58203 , xlink:href="https://doi.org/10.1007/s00127-020-01942-5"
- Description: Purpose: To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs. Methods: Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs. Results: In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Signifcant predictors of any SUD were younger age (41–55 vs. 21–30: OR=0.7, 95% CI=0.5–0.9), male sex (OR=8.6, 95% CI=5.1–14.6), inpatient status (OR=1.7, 95% CI=1.3–2.1), post-traumatic stress symptoms (OR=4.6, 95% CI=1.6–13.3), legal (OR=3.4, 95% CI=2.0–5.5) and economic problems (OR=1.4, 95% CI=1.0–2.0). Methamphetamine use disorders occurred signifcantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were signifcantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were signifcantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs. Conclusion: SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.
- Full Text:
Prioritisation of targets for weed biological control I: a review of existing prioritisation schemes and development of a system for South Africa
- Downey, Paul O, Paterson, Iain D, Canavan, Kim N, Hill, Martin P
- Authors: Downey, Paul O , Paterson, Iain D , Canavan, Kim N , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417763 , vital:71484 , xlink:href="https://doi.org/10.1080/09583157.2021.1918636"
- Description: Biological control is widely utilised for the management of invasive alien plants (IAP). With the ever-increasing number of IAPs, it is important to prioritise targets for biocontrol in order to maximise the use of resources and the chances of success. This paper reviewed 12 previous systems developed to prioritise plant targets for biocontrol. The review underpins the selection of attributes and methodologies for the prioritisation of targets for biocontrol in South Africa. All of the previous systems are purpose-built and context-specific, so a new system is required for the South African setting. Previous prioritisation systems were assessed based on the attributes and methodology adopted. The attributes of previous systems were grouped into three sections, being (1) impact/importance of the target plant, (2) likelihood of achieving success, and (3) investment required. Nineteen attributes from previous systems are included in the new system, while nine were excluded due to a requirement for legislation and/or research, or because they conflicted with objectives of the new system in some way. Two methodological approaches were identified for how systems sourced information, either sourcing information through expert knowledge or the use of available literature and data. This information was then applied through either a quantitative or qualitative scoring method. A quantitative scoring method, with information sourced from available resources, was selected as the most appropriate methodology in the context of the new system for South Africa. This review streamlined the development and testing of the South African Biological Control Target Selection system.
- Full Text:
- Authors: Downey, Paul O , Paterson, Iain D , Canavan, Kim N , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417763 , vital:71484 , xlink:href="https://doi.org/10.1080/09583157.2021.1918636"
- Description: Biological control is widely utilised for the management of invasive alien plants (IAP). With the ever-increasing number of IAPs, it is important to prioritise targets for biocontrol in order to maximise the use of resources and the chances of success. This paper reviewed 12 previous systems developed to prioritise plant targets for biocontrol. The review underpins the selection of attributes and methodologies for the prioritisation of targets for biocontrol in South Africa. All of the previous systems are purpose-built and context-specific, so a new system is required for the South African setting. Previous prioritisation systems were assessed based on the attributes and methodology adopted. The attributes of previous systems were grouped into three sections, being (1) impact/importance of the target plant, (2) likelihood of achieving success, and (3) investment required. Nineteen attributes from previous systems are included in the new system, while nine were excluded due to a requirement for legislation and/or research, or because they conflicted with objectives of the new system in some way. Two methodological approaches were identified for how systems sourced information, either sourcing information through expert knowledge or the use of available literature and data. This information was then applied through either a quantitative or qualitative scoring method. A quantitative scoring method, with information sourced from available resources, was selected as the most appropriate methodology in the context of the new system for South Africa. This review streamlined the development and testing of the South African Biological Control Target Selection system.
- Full Text:
Prioritising biological control agents for release against Sporobolus pyramidalis and Sporobolus natalensis (Poaceae) in Australia
- Authors: Sutton, Guy Frederick
- Date: 2021
- Subjects: Grasses -- Diseases and pests , Bruchophagus , Wasps , Alien plants -- Biological control -- Australia , Sporobolus -- Biological control -- Africa , Sporobolus -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insects as biological pest control agents -- Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172445 , vital:42201 , 10.21504/10962/172445
- Description: Sporobolus pyramidalis Beauv. and S. natalensis (Steud.) Th. Dur. and Schinz. (giant rat’s tail grass) (Poaceae), invade rangelands and pastures in eastern Australia, costing the livestock industry approximately AUS$ 60 million per annum in grazing losses. Mechanical and chemical control options are costly and largely ineffective. Biological control is viewed as the most promising control option, however this management strategy has largely been avoided for grasses, due to their perceived lack of suitably host-specific and damaging natural enemies. In this thesis, the prospects for using biological control against S. pyramidalis and S. natalensis in Australia was assessed, in light of these potential challenges. Climate matching models were used to identify high-priority geographic regions within the plants’ native distributions to survey for potential biological control agents. High-priority regions to perform surveys were identified by modelling the climatic suitability for S. pyramidalis and S. natalensis in sub-Saharan Africa (i.e. their potential native ranges’), and climatic compatibility with regions where biological control is intended in Australia. High-priority regions for S. pyramidalis included: (1) coastal East Africa, ranging from north-eastern South Africa to Uganda, including south-eastern DRC, (2) some parts of West Africa, including inland regions of the Ivory Coast and western Nigeria, (3) northern Angola and (4) eastern Madagascar, and for S. natalensis included: (1) eastern South Africa, (2) eastern Zimbabwe, (3) Burundi, (4) central Ethiopia and (5) central Madagascar. Prospective control agents collected from these regions have the highest probability of establishing and proliferating in Australia, if released. In surveys of the insect assemblages on S. pyramidalis and S. natalensis in the climatically-matched region of eastern South Africa fifteen insect herbivores associated with the grasses were identified. Insect feeding guild, geographic distributions, and seasonal abundances suggest that three stem-boring phytophagous wasps, Tetramesa sp. 1, Tetramesa sp. 2 and Bruchophagus sp. 1 (Hymenoptera: Eurytomidae), have potential as control agents. Species accumulation curves indicated that additional surveys in South Africa are unlikely to yield additional potential control agents. Field host-range surveys of 47 non-target grass species in South Africa showed that Tetramesa sp. 1, Tetramesa sp. 2, and Bruchophagus sp. 1, were only recorded from S. pyramidalis and S. natalensis. Integrating field host-range with phylogenetic relationships between plant species indicated that no native Australian Sporobolus species or economic crops and pastures are expected to be attacked by these wasps. All three wasp species are predicted to be suitably host-specific for release in Australia. Three other endophagous herbivores attacked non-target native African Sporobolus species that share a close phylogenetic relationship to native Australian Sporobolus species, and therefore, demonstrate considerable risk of non-target damage. These species should not be considered as potential control agents. Under native-range, open-field conditions, Tetramesa sp. 1 caused an approximately 5-fold greater reduction in plant survival and reproductive output than Tetramesa sp. 2 and Bruchophagus sp. 1. Tetramesa sp. 1 in combination with Tetramesa sp. 2 did not significantly increase the level of damage, while Bruchophagus sp. 1 may decrease the efficiency of Tetramesa sp. 1, if released in combination. Tetramesa 1 is therefore the most promising candidate agent. Prioritising potential agents using predicted efficacy allowed otherwise equally suitable prospective agents to be prioritised in a strategic manner. Prioritising which natural enemies to target as biological control agents is a complex task. Field host range and damage assessments in the native range may provide more realistic data than typical studies performed under artificial conditions in a laboratory or quarantine. Moreover, it could assist practitioners in prioritising the most suitable agent(s) at the earliest stage in the programme as possible. This study demonstrated that grasses are suitable targets for biological control as they can harbour host-specific and damaging natural enemies.
- Full Text:
- Authors: Sutton, Guy Frederick
- Date: 2021
- Subjects: Grasses -- Diseases and pests , Bruchophagus , Wasps , Alien plants -- Biological control -- Australia , Sporobolus -- Biological control -- Africa , Sporobolus -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insects as biological pest control agents -- Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172445 , vital:42201 , 10.21504/10962/172445
- Description: Sporobolus pyramidalis Beauv. and S. natalensis (Steud.) Th. Dur. and Schinz. (giant rat’s tail grass) (Poaceae), invade rangelands and pastures in eastern Australia, costing the livestock industry approximately AUS$ 60 million per annum in grazing losses. Mechanical and chemical control options are costly and largely ineffective. Biological control is viewed as the most promising control option, however this management strategy has largely been avoided for grasses, due to their perceived lack of suitably host-specific and damaging natural enemies. In this thesis, the prospects for using biological control against S. pyramidalis and S. natalensis in Australia was assessed, in light of these potential challenges. Climate matching models were used to identify high-priority geographic regions within the plants’ native distributions to survey for potential biological control agents. High-priority regions to perform surveys were identified by modelling the climatic suitability for S. pyramidalis and S. natalensis in sub-Saharan Africa (i.e. their potential native ranges’), and climatic compatibility with regions where biological control is intended in Australia. High-priority regions for S. pyramidalis included: (1) coastal East Africa, ranging from north-eastern South Africa to Uganda, including south-eastern DRC, (2) some parts of West Africa, including inland regions of the Ivory Coast and western Nigeria, (3) northern Angola and (4) eastern Madagascar, and for S. natalensis included: (1) eastern South Africa, (2) eastern Zimbabwe, (3) Burundi, (4) central Ethiopia and (5) central Madagascar. Prospective control agents collected from these regions have the highest probability of establishing and proliferating in Australia, if released. In surveys of the insect assemblages on S. pyramidalis and S. natalensis in the climatically-matched region of eastern South Africa fifteen insect herbivores associated with the grasses were identified. Insect feeding guild, geographic distributions, and seasonal abundances suggest that three stem-boring phytophagous wasps, Tetramesa sp. 1, Tetramesa sp. 2 and Bruchophagus sp. 1 (Hymenoptera: Eurytomidae), have potential as control agents. Species accumulation curves indicated that additional surveys in South Africa are unlikely to yield additional potential control agents. Field host-range surveys of 47 non-target grass species in South Africa showed that Tetramesa sp. 1, Tetramesa sp. 2, and Bruchophagus sp. 1, were only recorded from S. pyramidalis and S. natalensis. Integrating field host-range with phylogenetic relationships between plant species indicated that no native Australian Sporobolus species or economic crops and pastures are expected to be attacked by these wasps. All three wasp species are predicted to be suitably host-specific for release in Australia. Three other endophagous herbivores attacked non-target native African Sporobolus species that share a close phylogenetic relationship to native Australian Sporobolus species, and therefore, demonstrate considerable risk of non-target damage. These species should not be considered as potential control agents. Under native-range, open-field conditions, Tetramesa sp. 1 caused an approximately 5-fold greater reduction in plant survival and reproductive output than Tetramesa sp. 2 and Bruchophagus sp. 1. Tetramesa sp. 1 in combination with Tetramesa sp. 2 did not significantly increase the level of damage, while Bruchophagus sp. 1 may decrease the efficiency of Tetramesa sp. 1, if released in combination. Tetramesa 1 is therefore the most promising candidate agent. Prioritising potential agents using predicted efficacy allowed otherwise equally suitable prospective agents to be prioritised in a strategic manner. Prioritising which natural enemies to target as biological control agents is a complex task. Field host range and damage assessments in the native range may provide more realistic data than typical studies performed under artificial conditions in a laboratory or quarantine. Moreover, it could assist practitioners in prioritising the most suitable agent(s) at the earliest stage in the programme as possible. This study demonstrated that grasses are suitable targets for biological control as they can harbour host-specific and damaging natural enemies.
- Full Text:
Progress and prospects for the biological control of invasive alien grasses Poaceae) in South Africa
- Sutton, Guy F, Bownes, Angela, Visser, Vernon, Mapaura, Anthony, Canavan, Kim N
- Authors: Sutton, Guy F , Bownes, Angela , Visser, Vernon , Mapaura, Anthony , Canavan, Kim N
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414448 , vital:71147 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a12"
- Description: Historically, invasive alien grasses have not been considered a major threat in South Africa, and as a result, very few resources are allocated to their management. However, there is an increasing awareness of the severe environmental and socio-economic impacts of invasive grasses and the need for appropriate management options for their control. South Africa has a long history of successfully implementing weed biological control (biocontrol) to manage invasive alien plants, however much like the rest of the world, invasive grasses do not feature prominently as targets for biocontrol. The implementation and early indicators of success of the few grass biocontrol programmes globally and the finding that grasses can be suitable targets, suggests that biocontrol could start to play an important role in managing invasive alien grasses in South Africa. In this paper, we evaluated the prospects for implementing novel grass biocontrol projects over the next ten years against 48 grasses that have been determined to represent the highest risk based on their current environmental and economic impacts. The grasses were ranked in order of priority using the Biological Control Target Selection system. Five grasses were prioritised – Arundo donax L., Cortaderia jubata (Lem.) Stapf, Cortaderia selloana (Schult and Schult) Asch. and Graebn., Nassella trichotoma (Hack. ex Arech.), and Glyceria maxima (Hartm.) Holmb., based on attributes that make them suitable biocontrol targets. Arundo donax has already been the target of a biocontrol programme in South Africa. We reviewed the progress made towards the biocontrol of this species and discuss how this programme could be developed going forward. Moreover, we outline how biocontrol could be implemented to manage the remaining four high-priority targets. While biocontrol of grasses is not without its challenges (e.g. unresolved taxonomies, conflicts of interest and a lack of supporting legislation), South Africa has an opportunity to learn from existing global research and begin to invest in biocontrol of high-priority species that are in most need of control.
- Full Text:
Progress and prospects for the biological control of invasive alien grasses Poaceae) in South Africa
- Authors: Sutton, Guy F , Bownes, Angela , Visser, Vernon , Mapaura, Anthony , Canavan, Kim N
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414448 , vital:71147 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a12"
- Description: Historically, invasive alien grasses have not been considered a major threat in South Africa, and as a result, very few resources are allocated to their management. However, there is an increasing awareness of the severe environmental and socio-economic impacts of invasive grasses and the need for appropriate management options for their control. South Africa has a long history of successfully implementing weed biological control (biocontrol) to manage invasive alien plants, however much like the rest of the world, invasive grasses do not feature prominently as targets for biocontrol. The implementation and early indicators of success of the few grass biocontrol programmes globally and the finding that grasses can be suitable targets, suggests that biocontrol could start to play an important role in managing invasive alien grasses in South Africa. In this paper, we evaluated the prospects for implementing novel grass biocontrol projects over the next ten years against 48 grasses that have been determined to represent the highest risk based on their current environmental and economic impacts. The grasses were ranked in order of priority using the Biological Control Target Selection system. Five grasses were prioritised – Arundo donax L., Cortaderia jubata (Lem.) Stapf, Cortaderia selloana (Schult and Schult) Asch. and Graebn., Nassella trichotoma (Hack. ex Arech.), and Glyceria maxima (Hartm.) Holmb., based on attributes that make them suitable biocontrol targets. Arundo donax has already been the target of a biocontrol programme in South Africa. We reviewed the progress made towards the biocontrol of this species and discuss how this programme could be developed going forward. Moreover, we outline how biocontrol could be implemented to manage the remaining four high-priority targets. While biocontrol of grasses is not without its challenges (e.g. unresolved taxonomies, conflicts of interest and a lack of supporting legislation), South Africa has an opportunity to learn from existing global research and begin to invest in biocontrol of high-priority species that are in most need of control.
- Full Text:
Promising photodynamic antimicrobial activity of polyimine substituted zinc phthalocyanine and its polycationic derivative when conjugated to nitrogen, sulfur, co-doped graphene quantum dots against Staphylococcus aureus
- Sen, Pinar, Nyokong, Tebello
- Authors: Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185304 , vital:44363 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102300"
- Description: Antimicrobial resistance is a most important problem facing the treatment of infectious diseases. Antimicrobial photodynamic therapy is an alternative treatment strategy, considered to be cost-effective and feasible. For this purpose, octa-imine substituted ZnPc (3) have been prepared and conjugated to nitrogen, sulfur co-doped graphene quantum dots (N,S-GQDs) through π-π stacking. The photophysical and photochemical properties of Pc alone and and Pc-conjugated to the GQD nanomaterial such as absorption, fluorescence, fluorescence life time, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions before in vitro cell studies. The PACT activity of prepared structures was investigated against Gram-positive (Staphylococcus aureus). Our results suggest that the in the case of conjugation of zinc Pc to N,S-GQDs, photodynamic inactivation increased with the 100 % reduction percentage.
- Full Text:
- Authors: Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185304 , vital:44363 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102300"
- Description: Antimicrobial resistance is a most important problem facing the treatment of infectious diseases. Antimicrobial photodynamic therapy is an alternative treatment strategy, considered to be cost-effective and feasible. For this purpose, octa-imine substituted ZnPc (3) have been prepared and conjugated to nitrogen, sulfur co-doped graphene quantum dots (N,S-GQDs) through π-π stacking. The photophysical and photochemical properties of Pc alone and and Pc-conjugated to the GQD nanomaterial such as absorption, fluorescence, fluorescence life time, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions before in vitro cell studies. The PACT activity of prepared structures was investigated against Gram-positive (Staphylococcus aureus). Our results suggest that the in the case of conjugation of zinc Pc to N,S-GQDs, photodynamic inactivation increased with the 100 % reduction percentage.
- Full Text:
Prospects for the biological control of Northern Temperate Weeds in South Africa
- Authors: Martin, Grant D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414478 , vital:71151 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a10"
- Description: The Northern Temperate Weeds programme is a novel biological control (biocontrol) programme started in 2017, with the aim of reducing the impacts of northern temperate weeds that are common, widespread and problematic in the high elevation grasslands of South Africa. As these regions are the most important systems for water security, providing nearly 50% of all water run-off, it is surprising that these species were not targeted for biocontrol previously. Thus far, research has focused on biocontrol feasibility as well as ecological and socio-economic impact studies on several northern temperate weeds, including Pyracantha angustifolia (Franch.) C.K.Schneid, Rosa rubiginosa L., Cotoneaster spp., Rubus spp., (all Rosaceae) and Salix spp. (Salicaceae). In addition, research conducted in the USA and Europe on the natural enemies associated with two of these species, Robinia pseudoacacia L. and Gleditsia triacanthos L. (both Fabaceae and native to the USA), have provided South African researchers with the necessary foundation to initiate programmes against these weeds. Research in South Africa is currently focused on pre-release studies on R. pseudoacacia, using the leaf miner Odontota dorsalis Thunberg (Coleoptera: Chrysomelidae) and the black locust midge Obolodiplosis robiniae Haldeman (Diptera: Cecidomyiidae), and on G. triacanthos, using a seed bruchid, Amblycerus robiniae F. (Coleoptera: Chrysomelidae). Progress with these programmes and potential constraints that may limit success, are discussed.
- Full Text:
- Authors: Martin, Grant D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414478 , vital:71151 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a10"
- Description: The Northern Temperate Weeds programme is a novel biological control (biocontrol) programme started in 2017, with the aim of reducing the impacts of northern temperate weeds that are common, widespread and problematic in the high elevation grasslands of South Africa. As these regions are the most important systems for water security, providing nearly 50% of all water run-off, it is surprising that these species were not targeted for biocontrol previously. Thus far, research has focused on biocontrol feasibility as well as ecological and socio-economic impact studies on several northern temperate weeds, including Pyracantha angustifolia (Franch.) C.K.Schneid, Rosa rubiginosa L., Cotoneaster spp., Rubus spp., (all Rosaceae) and Salix spp. (Salicaceae). In addition, research conducted in the USA and Europe on the natural enemies associated with two of these species, Robinia pseudoacacia L. and Gleditsia triacanthos L. (both Fabaceae and native to the USA), have provided South African researchers with the necessary foundation to initiate programmes against these weeds. Research in South Africa is currently focused on pre-release studies on R. pseudoacacia, using the leaf miner Odontota dorsalis Thunberg (Coleoptera: Chrysomelidae) and the black locust midge Obolodiplosis robiniae Haldeman (Diptera: Cecidomyiidae), and on G. triacanthos, using a seed bruchid, Amblycerus robiniae F. (Coleoptera: Chrysomelidae). Progress with these programmes and potential constraints that may limit success, are discussed.
- Full Text:
Push-pull type Co (III) corroles
- Niu, Yingjie, Zhu, Weihua, Mack, John, Dubazana, Nadine, Nyokong, Tebello, Fu, Bo, Xu, Haijun, Liang, Xu
- Authors: Niu, Yingjie , Zhu, Weihua , Mack, John , Dubazana, Nadine , Nyokong, Tebello , Fu, Bo , Xu, Haijun , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190826 , vital:45032 , xlink:href="https://doi.org/10.1142/S1088424621500279"
- Description: The rational design and preparation of three A2B type Co(III)triarylcorroles with push- and pull-substituents are reported. The structure-property relationships were identified by comparing their optically spectroscopic and electrochemical properties to trends predicted in DFT and TD-DFT calculations. The results demonstrate that the Co(III)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolutions (HERs) and oxygen reductions (ORRs), and that their reactivity can be modulated by changing the meso-B-substituent of the Co(III)Corroles.
- Full Text:
- Authors: Niu, Yingjie , Zhu, Weihua , Mack, John , Dubazana, Nadine , Nyokong, Tebello , Fu, Bo , Xu, Haijun , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190826 , vital:45032 , xlink:href="https://doi.org/10.1142/S1088424621500279"
- Description: The rational design and preparation of three A2B type Co(III)triarylcorroles with push- and pull-substituents are reported. The structure-property relationships were identified by comparing their optically spectroscopic and electrochemical properties to trends predicted in DFT and TD-DFT calculations. The results demonstrate that the Co(III)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolutions (HERs) and oxygen reductions (ORRs), and that their reactivity can be modulated by changing the meso-B-substituent of the Co(III)Corroles.
- Full Text:
Pyrosequencing and phenotypic microarray to decipher bacterial community variation in Sorghum bicolor (L.) Moench rhizosphere
- Kumar, Ashwani, Dubey, Anamika, Malla, Muneer A, Dames, Joanna F
- Authors: Kumar, Ashwani , Dubey, Anamika , Malla, Muneer A , Dames, Joanna F
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440417 , vital:73781 , https://doi.org/10.1007/s11274-022-03288-3
- Description: Different cultivation practices and climatic conditions play an important role in governing and modulating soil microbial communities as well as soil health. This study investigated, for the first time, keystone microbial taxa inhabiting the rhizosphere of sweet sorghum (Sorghum bicolor) under extensive cultivation practices at three different field sites of South Africa (North West-South (ASHSOIL1); Mpumalanga-West – (ASHSOIL2); and Free State-North West – (ASHSOIL3)). Soil analysis of these sites revealed differences in P, K, Mg, and pH. 16S rRNA amplicon sequencing data revealed that the rhizosphere bacterial microbiome differed significantly both in the structure and composition across the samples. The sequencing data revealed that at the phylum level, the dominant group was Cyanobacteria with a relative abundance of 63.3%, 71.8%, and 81.6% from ASHSOIL1, ASHSOIL2, and ASHSOIL3, respectively. Putative metabolic requirements analyzed by METAGENassist software revealed the ASHSOIL1 sample as the prominent ammonia degrader (21.1%), followed by ASHSOIL3 (17.3%) and ASHSOIL2 (11.1%). The majority of core-microbiome taxa were found to be from Cyanobacteria, Bacteroidetes, and Proteobacteria. Functionally, community-level physiological profiling (CLPP) analysis revealed that the metabolic activity of the bacterial community in ASHSOIL3 was the highest, followed by ASHSOIL1 and ASHSOIL2. This study showed that soil pH and nutrient availability and cultivation practices played significant roles in governing the bacterial community composition in the sorghum rhizosphere across the different sites.
- Full Text:
- Authors: Kumar, Ashwani , Dubey, Anamika , Malla, Muneer A , Dames, Joanna F
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440417 , vital:73781 , https://doi.org/10.1007/s11274-022-03288-3
- Description: Different cultivation practices and climatic conditions play an important role in governing and modulating soil microbial communities as well as soil health. This study investigated, for the first time, keystone microbial taxa inhabiting the rhizosphere of sweet sorghum (Sorghum bicolor) under extensive cultivation practices at three different field sites of South Africa (North West-South (ASHSOIL1); Mpumalanga-West – (ASHSOIL2); and Free State-North West – (ASHSOIL3)). Soil analysis of these sites revealed differences in P, K, Mg, and pH. 16S rRNA amplicon sequencing data revealed that the rhizosphere bacterial microbiome differed significantly both in the structure and composition across the samples. The sequencing data revealed that at the phylum level, the dominant group was Cyanobacteria with a relative abundance of 63.3%, 71.8%, and 81.6% from ASHSOIL1, ASHSOIL2, and ASHSOIL3, respectively. Putative metabolic requirements analyzed by METAGENassist software revealed the ASHSOIL1 sample as the prominent ammonia degrader (21.1%), followed by ASHSOIL3 (17.3%) and ASHSOIL2 (11.1%). The majority of core-microbiome taxa were found to be from Cyanobacteria, Bacteroidetes, and Proteobacteria. Functionally, community-level physiological profiling (CLPP) analysis revealed that the metabolic activity of the bacterial community in ASHSOIL3 was the highest, followed by ASHSOIL1 and ASHSOIL2. This study showed that soil pH and nutrient availability and cultivation practices played significant roles in governing the bacterial community composition in the sorghum rhizosphere across the different sites.
- Full Text:
Quantifying the shift in network usage upon bandwidth upgrade
- Okuthe, J A, Terzoli, Alfredo
- Authors: Okuthe, J A , Terzoli, Alfredo
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431003 , vital:72735 , https://doi.org/10.1007/978-3-031-06374-9_22
- Description: Traffic flow classification is an important enabler in network design, ca-pacity planning, identification of user requirements and possible track-ing of user population growth based on network usage. In this paper, results from the Internet traffic flow characterization in 1 Mbps commu-nity network for a three-week snapshot representing three months of study show that during peak traffic, the network is overwhelmed and service degradation occurs. When the network is upgraded to 10 Mbps the network bandwidth utilization immediately increases dramatically to close in on the new capacity with 20% left unused during peak traffic. The situation gets worse one month later where the network utilization is only 3% away from the maximum capacity. Traffic categorization show that the applications crossing the network are legitimate and accepta-ble. Since 10 Mbps bandwidth is the capacity that is sustainable for the community and supported by existing technology, bandwidth manage-ment is essential to ensure the network remains usable and continues to provide acceptable user experience.
- Full Text:
- Authors: Okuthe, J A , Terzoli, Alfredo
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431003 , vital:72735 , https://doi.org/10.1007/978-3-031-06374-9_22
- Description: Traffic flow classification is an important enabler in network design, ca-pacity planning, identification of user requirements and possible track-ing of user population growth based on network usage. In this paper, results from the Internet traffic flow characterization in 1 Mbps commu-nity network for a three-week snapshot representing three months of study show that during peak traffic, the network is overwhelmed and service degradation occurs. When the network is upgraded to 10 Mbps the network bandwidth utilization immediately increases dramatically to close in on the new capacity with 20% left unused during peak traffic. The situation gets worse one month later where the network utilization is only 3% away from the maximum capacity. Traffic categorization show that the applications crossing the network are legitimate and accepta-ble. Since 10 Mbps bandwidth is the capacity that is sustainable for the community and supported by existing technology, bandwidth manage-ment is essential to ensure the network remains usable and continues to provide acceptable user experience.
- Full Text:
Rapid Synthesis of Thiol-Co-Capped-CdTe/CdSe/ZnSe Core Shell-Shell Nanoparticles
- Daramola, Olamide, Siwe-Noundou, Xavier, Tseki, Potlaki, Krause, Rui W M
- Authors: Daramola, Olamide , Siwe-Noundou, Xavier , Tseki, Potlaki , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191758 , vital:45161 , xlink:href="https://doi.org/10.3390/nano11051193"
- Description: CdTe QDs has been demonstrated in many studies to possess good outstanding optical and photo-physical properties. However, it has been established from literature that the toxic Cd2+ that tends to leak out into nearby solutions can be protected by less toxic ZnS or ZnSe shells leading to the synthesis of core-shells and multi-core-shells. Hence, this has allowed the synthesis of CdTe multi-core-shells to have gained much interest. The preparation of most CdTe multi-core-shells reported from various studies usually has a longer reaction time (6–24 h) in reaching their highest emission maxima. The synthesis of CdTe multi-core-shells in this study only took 35 min to obtain a highest emission maximum compared to what has been reported from the literature. CdTe multi-core-shells were synthesized by injecting 7, 14, and 21 mL each of Zn complex solution and Se ions into the reacting mixture containing CdTe core-shells (3 h) at 5 min intervals over a 35 min reaction time. The emission maxima of the MPA-TGA-CdTe multi-core-shells at 21 mL injection was recorded around 625 nm. Therefore, we are reporting the rapid synthesis of five different thiol co-capped CdTe/CdSe/ZnSe multi-core-shell QDs with the highest emission maxima obtained at 35 min reaction time.
- Full Text:
- Authors: Daramola, Olamide , Siwe-Noundou, Xavier , Tseki, Potlaki , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191758 , vital:45161 , xlink:href="https://doi.org/10.3390/nano11051193"
- Description: CdTe QDs has been demonstrated in many studies to possess good outstanding optical and photo-physical properties. However, it has been established from literature that the toxic Cd2+ that tends to leak out into nearby solutions can be protected by less toxic ZnS or ZnSe shells leading to the synthesis of core-shells and multi-core-shells. Hence, this has allowed the synthesis of CdTe multi-core-shells to have gained much interest. The preparation of most CdTe multi-core-shells reported from various studies usually has a longer reaction time (6–24 h) in reaching their highest emission maxima. The synthesis of CdTe multi-core-shells in this study only took 35 min to obtain a highest emission maximum compared to what has been reported from the literature. CdTe multi-core-shells were synthesized by injecting 7, 14, and 21 mL each of Zn complex solution and Se ions into the reacting mixture containing CdTe core-shells (3 h) at 5 min intervals over a 35 min reaction time. The emission maxima of the MPA-TGA-CdTe multi-core-shells at 21 mL injection was recorded around 625 nm. Therefore, we are reporting the rapid synthesis of five different thiol co-capped CdTe/CdSe/ZnSe multi-core-shell QDs with the highest emission maxima obtained at 35 min reaction time.
- Full Text:
Reconsidering the Rhodesian war through white soldier-writers’ stories
- Authors: Baines, Gary F
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/450070 , vital:74880 , https://www.scielo.org.za/pdf/hist/v66n2/08.pdf
- Description: The title of Luise White’s new book recalls the truism that every war is fought twice over: it is waged in the first instance on the battlefield and, thereafter, contested via representations such as books, films and social media. White's focus is on the memoirs and novels of Rhodesia's civil war written and (often self-) published by veterans. These soldier-authors participated in a war of counterinsurgency against guerrillas of the Zimbabwean liberation movements and, subsequently, mounted a rearguard struggle to monopolise the story of the Rhodesian war through their writings. White reflects that their stories of counterinsurgency were “more successful as a story than they were in practice” (p 223). This does not, ipso facto, invalidate their personal experience of war nor the entire corpus of Rhodesian memoirs as evidence. But evidence of what? White reckons that they “reveal soldiers’ ideas about and analysis of wartime practices” (p 31). In other words, memoirs serve not as historical records per se but as experiential evidence of how the war was conducted by soldiers as actors in their own right. Only in this sense can the memoirs be treated as primary sources.
- Full Text:
- Authors: Baines, Gary F
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/450070 , vital:74880 , https://www.scielo.org.za/pdf/hist/v66n2/08.pdf
- Description: The title of Luise White’s new book recalls the truism that every war is fought twice over: it is waged in the first instance on the battlefield and, thereafter, contested via representations such as books, films and social media. White's focus is on the memoirs and novels of Rhodesia's civil war written and (often self-) published by veterans. These soldier-authors participated in a war of counterinsurgency against guerrillas of the Zimbabwean liberation movements and, subsequently, mounted a rearguard struggle to monopolise the story of the Rhodesian war through their writings. White reflects that their stories of counterinsurgency were “more successful as a story than they were in practice” (p 223). This does not, ipso facto, invalidate their personal experience of war nor the entire corpus of Rhodesian memoirs as evidence. But evidence of what? White reckons that they “reveal soldiers’ ideas about and analysis of wartime practices” (p 31). In other words, memoirs serve not as historical records per se but as experiential evidence of how the war was conducted by soldiers as actors in their own right. Only in this sense can the memoirs be treated as primary sources.
- Full Text:
Review of a Course-supported Design Research Intervention Process for the Inclusion of Education for Sustainable Development in School Subject Disciplines
- O’Donoghue, R, Misser, Shanu, Snow-Macleod, Janet
- Authors: O’Donoghue, R , Misser, Shanu , Snow-Macleod, Janet
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435180 , vital:73136 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: The study was informed by an expansion of the ‘design research’ reported by McKenny and Reeves (2012) and it developed as a collaborative design process similar to that described by Voogt, Laferriere, Breuleux, Itow, Hickey and McKenny (2015). Voogt et al. approached design research as a successive and developing process of formative work by participants working together to design and assess a learning programme. In our case the design work was undertaken within a course-supported process of ESD design innovation among participating teachers and subject advisors.
- Full Text:
- Authors: O’Donoghue, R , Misser, Shanu , Snow-Macleod, Janet
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435180 , vital:73136 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: The study was informed by an expansion of the ‘design research’ reported by McKenny and Reeves (2012) and it developed as a collaborative design process similar to that described by Voogt, Laferriere, Breuleux, Itow, Hickey and McKenny (2015). Voogt et al. approached design research as a successive and developing process of formative work by participants working together to design and assess a learning programme. In our case the design work was undertaken within a course-supported process of ESD design innovation among participating teachers and subject advisors.
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Review of the Traditional Uses, Phytochemistry, and Pharmacological Activities of Rhoicissus Species (Vitaceae)
- Dube, Nondumiso, Siwe-Noundou, Xavier, Krause, Rui W M, Kemboi, Douglas, Tembu, Vuyelwa J, Manicum, Amanda-Lee
- Authors: Dube, Nondumiso , Siwe-Noundou, Xavier , Krause, Rui W M , Kemboi, Douglas , Tembu, Vuyelwa J , Manicum, Amanda-Lee
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191769 , vital:45162 , xlink:href="https://doi.org/10.3390/molecules26082306"
- Description: Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.
- Full Text:
- Authors: Dube, Nondumiso , Siwe-Noundou, Xavier , Krause, Rui W M , Kemboi, Douglas , Tembu, Vuyelwa J , Manicum, Amanda-Lee
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191769 , vital:45162 , xlink:href="https://doi.org/10.3390/molecules26082306"
- Description: Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.
- Full Text:
Revision of the Afrotropical genus Fainia Zumpt, 1958, with notes on the morphology of Rhiniidae subfamilies (Diptera, Oestroidea)
- Thomas-Cabianca, Arianna, Martínez-Sánchez, Anabel, Villet, Martin H, Rojo, Santos
- Authors: Thomas-Cabianca, Arianna , Martínez-Sánchez, Anabel , Villet, Martin H , Rojo, Santos
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441446 , vital:73889 , 10.3897/zookeys.1033.58539
- Description: The taxonomy and diversity of Fainia Zumpt, 1958, an exclusive Afrotropical genus, had not been reviewed recently. The genus included six nominal species, but the status of several of them was debated. Identification of most Fainia species depends on characters of the male terminalia; females are poorly known and, in several cases, are not adequately diagnosed. We conducted a taxonomic revision of the genus and generated identification tools. Based on the study of type material and specimens available in entomological collections in Africa and Europe, we recognise here three of the six species as valid (F. albitarsis (Macquart, 1846), F. elongata (Bezzi, 1908) and F. inexpectata Zumpt, 1973). We also provide an identification key to both sexes, redescriptions of the species, updated distribution records and high resolution photographs of males’ and females’ habitus and male terminalia. The description of Fainia kagerana Lehrer, 2007a nom. nud. is an invalid nomenclatural act in terms of ICZN Article 13.1. 1. Based on examinations of their holotypes, F. sambura Lehrer, 2008 syn. nov. is proposed as a junior synonym of F. albitarsis; F. kirinyaga Lehrer, 2007b syn. nov. is proposed as a junior synonym of F. inexpectata; and Fainia giriama Lehrer, 2007b is moved from the genus Fainia to the genus Rhinia Robineau-Desvoidy, as Rhinia giriama (Lehrer, 2007b) comb. nov.. We propose two apomorphies that support the status of the subfamily Rhiniinae.
- Full Text:
- Authors: Thomas-Cabianca, Arianna , Martínez-Sánchez, Anabel , Villet, Martin H , Rojo, Santos
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441446 , vital:73889 , 10.3897/zookeys.1033.58539
- Description: The taxonomy and diversity of Fainia Zumpt, 1958, an exclusive Afrotropical genus, had not been reviewed recently. The genus included six nominal species, but the status of several of them was debated. Identification of most Fainia species depends on characters of the male terminalia; females are poorly known and, in several cases, are not adequately diagnosed. We conducted a taxonomic revision of the genus and generated identification tools. Based on the study of type material and specimens available in entomological collections in Africa and Europe, we recognise here three of the six species as valid (F. albitarsis (Macquart, 1846), F. elongata (Bezzi, 1908) and F. inexpectata Zumpt, 1973). We also provide an identification key to both sexes, redescriptions of the species, updated distribution records and high resolution photographs of males’ and females’ habitus and male terminalia. The description of Fainia kagerana Lehrer, 2007a nom. nud. is an invalid nomenclatural act in terms of ICZN Article 13.1. 1. Based on examinations of their holotypes, F. sambura Lehrer, 2008 syn. nov. is proposed as a junior synonym of F. albitarsis; F. kirinyaga Lehrer, 2007b syn. nov. is proposed as a junior synonym of F. inexpectata; and Fainia giriama Lehrer, 2007b is moved from the genus Fainia to the genus Rhinia Robineau-Desvoidy, as Rhinia giriama (Lehrer, 2007b) comb. nov.. We propose two apomorphies that support the status of the subfamily Rhiniinae.
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SANCDB: an update on South African natural compounds and their readily available analogs
- Diallo, Bakary N, Glenister, Michael, Musyoka, Thommas M, Lobb, Kevin A, Taştan Bishop, Özlem
- Authors: Diallo, Bakary N , Glenister, Michael , Musyoka, Thommas M , Lobb, Kevin A , Taştan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451154 , vital:75023 , xlink:href="https://doi.org/10.1186/s13321-021-00514-2"
- Description: The dimeric dihydropyrimidine dehydrogenase (DPD), metalloenzyme, an adjunct anti-cancer drug target, contains highly specialized 4 × Fe2+4S2−4 clusters per chain. These clusters facilitate the catalysis of the rate-limiting step in the pyrimidine degradation pathway through a harmonized electron transfer cascade that triggers a redox catabolic reaction. In the process, the bulk of the administered 5-fluorouracil (5-FU) cancer drug is inactivated, while a small proportion is activated to nucleic acid antimetabolites. The occurrence of missense mutations in DPD protein within the general population, including those of African descent, has adverse toxicity effects due to altered 5-FU metabolism. Thus, deciphering mutation effects on protein structure and function is vital, especially for precision medicine purposes. We previously proposed combining molecular dynamics (MD) and dynamic residue network (DRN) analysis to decipher the molecular mechanisms of missense mutations in other proteins. However, the presence of Fe2+4S2−4 clusters in DPD poses a challenge for such in silico studies. The existing AMBER force field parameters cannot accurately describe the Fe2+ center coordination exhibited by this enzyme. Therefore, this study aimed to derive AMBER force field parameters for DPD enzyme Fe2+ centers, using the original Seminario method and the collation features Visual Force Field Derivation Toolkit as a supportive approach. All-atom MD simulations were performed to validate the results. Both approaches generated similar force field parameters, which accurately described the human DPD protein Fe2+4S2−4 cluster architecture. This information is crucial and opens new avenues for in silico cancer pharmacogenomics and drug discovery related research on 5-FU drug efficacy and toxicity issues.
- Full Text:
- Authors: Diallo, Bakary N , Glenister, Michael , Musyoka, Thommas M , Lobb, Kevin A , Taştan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451154 , vital:75023 , xlink:href="https://doi.org/10.1186/s13321-021-00514-2"
- Description: The dimeric dihydropyrimidine dehydrogenase (DPD), metalloenzyme, an adjunct anti-cancer drug target, contains highly specialized 4 × Fe2+4S2−4 clusters per chain. These clusters facilitate the catalysis of the rate-limiting step in the pyrimidine degradation pathway through a harmonized electron transfer cascade that triggers a redox catabolic reaction. In the process, the bulk of the administered 5-fluorouracil (5-FU) cancer drug is inactivated, while a small proportion is activated to nucleic acid antimetabolites. The occurrence of missense mutations in DPD protein within the general population, including those of African descent, has adverse toxicity effects due to altered 5-FU metabolism. Thus, deciphering mutation effects on protein structure and function is vital, especially for precision medicine purposes. We previously proposed combining molecular dynamics (MD) and dynamic residue network (DRN) analysis to decipher the molecular mechanisms of missense mutations in other proteins. However, the presence of Fe2+4S2−4 clusters in DPD poses a challenge for such in silico studies. The existing AMBER force field parameters cannot accurately describe the Fe2+ center coordination exhibited by this enzyme. Therefore, this study aimed to derive AMBER force field parameters for DPD enzyme Fe2+ centers, using the original Seminario method and the collation features Visual Force Field Derivation Toolkit as a supportive approach. All-atom MD simulations were performed to validate the results. Both approaches generated similar force field parameters, which accurately described the human DPD protein Fe2+4S2−4 cluster architecture. This information is crucial and opens new avenues for in silico cancer pharmacogenomics and drug discovery related research on 5-FU drug efficacy and toxicity issues.
- Full Text:
Scenario development
- Hichert, Tanya, Biggs, Reinette, de Vos, Alta, Peterson, Garry
- Authors: Hichert, Tanya , Biggs, Reinette , de Vos, Alta , Peterson, Garry
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433857 , vital:73005 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: Scenario development connects to various other methods, but in particular to futures analysis (Chapter 10) as it is also regarded as a futures analysis method. It warrants a separate chapter in addition to the other futures analysis methods (described in Chapter 10) because of its importance and widespread use. Scenario development also connects to facilitated dialogues (Chapter 9), serious games (Chapter 12), participatory modelling and planning (Chapter 13), dynamical systems modelling (Chapter 26) and agent-based modelling (Chapter 28).
- Full Text:
- Authors: Hichert, Tanya , Biggs, Reinette , de Vos, Alta , Peterson, Garry
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433857 , vital:73005 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: Scenario development connects to various other methods, but in particular to futures analysis (Chapter 10) as it is also regarded as a futures analysis method. It warrants a separate chapter in addition to the other futures analysis methods (described in Chapter 10) because of its importance and widespread use. Scenario development also connects to facilitated dialogues (Chapter 9), serious games (Chapter 12), participatory modelling and planning (Chapter 13), dynamical systems modelling (Chapter 26) and agent-based modelling (Chapter 28).
- Full Text:
Seasonal metabolic adjustments in an avian evolutionary relict restricted to mountain habitat
- Oswald, Krista N, Lee, Alan T K, Smit, Ben
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441638 , vital:73903 , https://doi.org/10.1016/j.jtherbio.2020.102815
- Description: For endotherms, maintaining body temperature during cold winters is energetically costly.Greater increase in winter maximum thermogenic capacity (Msum) has typically been correlated with improved cold tolerance. However, seasonal studies have shown equivocal direction change in basal metabolic rate (BMR) in winter, perhaps explained by latitude or phylogeny. We examined seasonal metabolic responses in the Cape rockjumper (Chaetops frenatus; “rockjumper”), a range-restricted mountain bird. We hypothesized that, given their mountain habitat preference, rockjumpers would be physiologically specialized for cooler air temperatures compared to other subtropical passerines. We measured body condition (using the ratio of Mb/tarsus), BMR, and Msum, in wild-living rockjumpers during winter and summer (n = 12 adults in winter –– 4 females, 8 males; n = 12 adults in summer –– 6 females, 6 males). We found birds had lesser BMR and thermal conductance, and greater Msum and body condition, in winter compared to summer. .
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- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441638 , vital:73903 , https://doi.org/10.1016/j.jtherbio.2020.102815
- Description: For endotherms, maintaining body temperature during cold winters is energetically costly.Greater increase in winter maximum thermogenic capacity (Msum) has typically been correlated with improved cold tolerance. However, seasonal studies have shown equivocal direction change in basal metabolic rate (BMR) in winter, perhaps explained by latitude or phylogeny. We examined seasonal metabolic responses in the Cape rockjumper (Chaetops frenatus; “rockjumper”), a range-restricted mountain bird. We hypothesized that, given their mountain habitat preference, rockjumpers would be physiologically specialized for cooler air temperatures compared to other subtropical passerines. We measured body condition (using the ratio of Mb/tarsus), BMR, and Msum, in wild-living rockjumpers during winter and summer (n = 12 adults in winter –– 4 females, 8 males; n = 12 adults in summer –– 6 females, 6 males). We found birds had lesser BMR and thermal conductance, and greater Msum and body condition, in winter compared to summer. .
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Segmentation of Tuta Absoluta’s Damage on Tomato Plants: A Computer Vision Approach
- Loyani, Loyani K, Bradshaw, Karen L, Machuze, Dina
- Authors: Loyani, Loyani K , Bradshaw, Karen L , Machuze, Dina
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440313 , vital:73765 , xlink:href="https://doi.org/10.1080/08839514.2021.1972254"
- Description: Tuta absoluta is a major threat to tomato production, causing losses ranging from 80% to 100% when not properly managed. Early detection of T. absoluta’s effects on tomato plants is important in controlling and preventing severe pest damage on tomatoes. In this study, we propose semantic and instance segmentation models based on U-Net and Mask RCNN, deep Convolutional Neural Networks (CNN) to segment the effects of T. absoluta on tomato leaf images at pixel level using field data. The results show that Mask RCNN achieved a mean Average Precision of 85.67%, while the U-Net model achieved an Intersection over Union of 78.60% and Dice coefficient of 82.86%. Both models can precisely generate segmentations indicating the exact spots/areas infested by T. absoluta in tomato leaves. The model will help farmers and extension officers make informed decisions to improve tomato productivity and rescue farmers from annual losses.
- Full Text:
- Authors: Loyani, Loyani K , Bradshaw, Karen L , Machuze, Dina
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440313 , vital:73765 , xlink:href="https://doi.org/10.1080/08839514.2021.1972254"
- Description: Tuta absoluta is a major threat to tomato production, causing losses ranging from 80% to 100% when not properly managed. Early detection of T. absoluta’s effects on tomato plants is important in controlling and preventing severe pest damage on tomatoes. In this study, we propose semantic and instance segmentation models based on U-Net and Mask RCNN, deep Convolutional Neural Networks (CNN) to segment the effects of T. absoluta on tomato leaf images at pixel level using field data. The results show that Mask RCNN achieved a mean Average Precision of 85.67%, while the U-Net model achieved an Intersection over Union of 78.60% and Dice coefficient of 82.86%. Both models can precisely generate segmentations indicating the exact spots/areas infested by T. absoluta in tomato leaves. The model will help farmers and extension officers make informed decisions to improve tomato productivity and rescue farmers from annual losses.
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Sex, gender and Uvalo/Letswalo centred spirituality
- Magadla, Siphokazi, Magoqwana, Babalwa, Motsemme, Nthabiseng, Mohoto, Lieketso
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng , Mohoto, Lieketso
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298663 , vital:57725 , xlink:href="https://doi.org/10.1080/02589001.2021.1909711"
- Description: In Male Daughters, Female Husbands (1987) Amadiume argues that the female orientation of Nnobi society and its emphasis on female industriousness is ‘derived from goddess Idemili – the ancestral religious deity’ (27). While Christianity dominates the outlook and conservatism of the post-colonial African state, we are seeing a growing public presence of African spiritual practitioners in southern Africa. The interview with Lieketso Gogo Mapitsi Mohoto reflects on her journey of becoming a healer. She uses the concept of ‘uvalo' to argue for deeper connected spiritual awareness within this practice of healing. Using the Nguni concept of uvalo, she refers to the fluid meaning of intuition also known as Umbilini among Xhosa-speaking people, while Sesotho speakers call it Letswalo. This intimate connection with the Divine can sometimes mean a sense of fear for ordinary people, while it promotes a deep sense of knowing for the spiritually conscious. Gogo Mapitsi's connections between spirituality and land, speak to Amadiume’s matrifocal understanding of productivity as linked to the goddess Idemili in Nnobi histories. Gogo Mapitsi reminds us that the multiple health, economic, psychological crises we face today are linked 'to how uvalo works.' She tells us that the 'cultivation of that inner knowing and the cultivation of trust in that knowing' is central to how a Sangoma understands and responds to the needs of their society.
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- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng , Mohoto, Lieketso
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298663 , vital:57725 , xlink:href="https://doi.org/10.1080/02589001.2021.1909711"
- Description: In Male Daughters, Female Husbands (1987) Amadiume argues that the female orientation of Nnobi society and its emphasis on female industriousness is ‘derived from goddess Idemili – the ancestral religious deity’ (27). While Christianity dominates the outlook and conservatism of the post-colonial African state, we are seeing a growing public presence of African spiritual practitioners in southern Africa. The interview with Lieketso Gogo Mapitsi Mohoto reflects on her journey of becoming a healer. She uses the concept of ‘uvalo' to argue for deeper connected spiritual awareness within this practice of healing. Using the Nguni concept of uvalo, she refers to the fluid meaning of intuition also known as Umbilini among Xhosa-speaking people, while Sesotho speakers call it Letswalo. This intimate connection with the Divine can sometimes mean a sense of fear for ordinary people, while it promotes a deep sense of knowing for the spiritually conscious. Gogo Mapitsi's connections between spirituality and land, speak to Amadiume’s matrifocal understanding of productivity as linked to the goddess Idemili in Nnobi histories. Gogo Mapitsi reminds us that the multiple health, economic, psychological crises we face today are linked 'to how uvalo works.' She tells us that the 'cultivation of that inner knowing and the cultivation of trust in that knowing' is central to how a Sangoma understands and responds to the needs of their society.
- Full Text: