The prevalence of insufficient iodine intake in pregnancy in Africa: protocol for a systematic review and meta-analysis
- Businge, Charles Bitamazire, Longo-Mbenza , Benjamin, Kengne, Andre Pascal
- Authors: Businge, Charles Bitamazire , Longo-Mbenza , Benjamin , Kengne, Andre Pascal
- Date: 2019
- Subjects: Africa , Iodine , Pregnancy
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5882 , vital:44662 , https://DOI:10.1186/s13643-019-1092-7
- Description: Background: Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods: A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion: This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal. Systematic review registration: PROSPERO CRD42018099434 Keywords: Iodine, Insufficiency, Pregnancy, Africa
- Full Text:
- Date Issued: 2019
- Authors: Businge, Charles Bitamazire , Longo-Mbenza , Benjamin , Kengne, Andre Pascal
- Date: 2019
- Subjects: Africa , Iodine , Pregnancy
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5882 , vital:44662 , https://DOI:10.1186/s13643-019-1092-7
- Description: Background: Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods: A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion: This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal. Systematic review registration: PROSPERO CRD42018099434 Keywords: Iodine, Insufficiency, Pregnancy, Africa
- Full Text:
- Date Issued: 2019
The prevalence of insufficient iodine intake in pregnancy in Africa: Protocol for a systematic review and meta-analysis
- Charles Bitamazire Businge, Benjamin Longo-Mbenza, Andre Pascal Kengne
- Authors: Charles Bitamazire Businge , Benjamin Longo-Mbenza , Andre Pascal Kengne
- Date: 22-8-2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3387 , vital:43338 , https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-019-1092-7#citeas
- Description: Background: Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods: A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal.
- Full Text:
- Date Issued: 22-8-2019
- Authors: Charles Bitamazire Businge , Benjamin Longo-Mbenza , Andre Pascal Kengne
- Date: 22-8-2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3387 , vital:43338 , https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-019-1092-7#citeas
- Description: Background: Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods: A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal.
- Full Text:
- Date Issued: 22-8-2019
Efficacy, acceptability and feasibility of mhealth technology in promoting adherence to anti-diabetic therapy and glycaemic control among diabetic patients in Eastern Cape, South Africa”
- Authors: Owolabi, Eyitayo Omolara
- Date: 2019
- Subjects: Diabetes
- Language: English
- Type: Thesis , Doctoral , PhD (Nursing)
- Identifier: http://hdl.handle.net/10353/16792 , vital:40774
- Description: Background: Diabetes mellitus is a disease of a significant public health concern and a leading cause of death and disability worldwide. In Africa, South Africa ranks second among countries with the highest burden of diabetes, and with a poor level of glycaemic control. mHealth technology is an innovative and cost-effective measure of promoting health and the use of text messaging for fostering health is evolving. In South Africa, there is hardly any study involving the use of mobile health technology, including text messaging for promoting health among diabetic patients. Purpose: The aim of this study was to determine the efficacy, feasibility and acceptability of mHealth in promoting adherence and glycaemic control among diabetic patients in resource-poor settings of the Eastern Cape Province of South Africa. Also, the study assessed the impact of text messaging on knowledge, selfmanagement behaviour, self-efficacy and health-related quality of life. Methodology: The study adopted a multi-centre, two-arm, parallel, randomised controlled trial design. Participants were randomly assigned to the intervention (n=108) and control arm (n=108). Participants’ socio-demographic information was obtained using the widely validated WHO STEPwise questionnaire, and a selfdeveloped questionnaire, including previously validated measurement scales were used to obtain information on adherence, self-management behaviour, self-efficacy and health-related quality of life. Participants in the intervention arm received daily text messages related to diabetes management and care for six months. Data were collected at baseline and six months post-intervention. Blood glucose, blood pressure and anthropometric measurements followed standard procedure. Mixed-model analysis was used to assess the impact of the SMS on random blood glucose while xi | P a g e linear and bivariate logistic regression were used to assess for effect on other clinical outcomes. Results: The mean age of the participants was 60.64 (SD± 11.58) years. The majority of the study participants had secondary level of education (95.3%) and earned 1500 to 14200 Rand per month (67.7%). For both the intervention and the control group, majority never used tobacco (98.10% vs 94.40%) or alcohol (88.00% vs 87.00%). Both arms of the study showed improvement in the primary outcome (blood glucose level), with no significant difference, the mean adjusted difference in blood glucose from baseline to six months post-intervention was 0.26 (-0.81 to 1.32), p=0.634. Also, the intervention did not have a significant effect on the secondary outcomes (knowledge, medication adherence, dietary adherence, adherence to physical activity, healthrelated quality of life, self-management behaviour and diabetes distress). Similarly, the intervention did not have any significant effect on secondary clinical outcomes such as weight (p=0.654), body mass index (p=0.439), systolic (p=0.610) and diastolic blood pressure (p=0.535). An overwhelming majority of the participants (90.74%) were pleased with the intervention and felt it was helpful. Of those who took part in the intervention, 91% completed the follow-up study after six months. Conclusion: The use of SMS is a highly acceptable and feasible adjunct to standard clinical care in the promotion of health among diabetic patients in this study setting. Although there was a little improvement, the efficacy of a unidirectional text messaging in promoting health outcomes in this study setting is still doubt
- Full Text:
- Date Issued: 2019
- Authors: Owolabi, Eyitayo Omolara
- Date: 2019
- Subjects: Diabetes
- Language: English
- Type: Thesis , Doctoral , PhD (Nursing)
- Identifier: http://hdl.handle.net/10353/16792 , vital:40774
- Description: Background: Diabetes mellitus is a disease of a significant public health concern and a leading cause of death and disability worldwide. In Africa, South Africa ranks second among countries with the highest burden of diabetes, and with a poor level of glycaemic control. mHealth technology is an innovative and cost-effective measure of promoting health and the use of text messaging for fostering health is evolving. In South Africa, there is hardly any study involving the use of mobile health technology, including text messaging for promoting health among diabetic patients. Purpose: The aim of this study was to determine the efficacy, feasibility and acceptability of mHealth in promoting adherence and glycaemic control among diabetic patients in resource-poor settings of the Eastern Cape Province of South Africa. Also, the study assessed the impact of text messaging on knowledge, selfmanagement behaviour, self-efficacy and health-related quality of life. Methodology: The study adopted a multi-centre, two-arm, parallel, randomised controlled trial design. Participants were randomly assigned to the intervention (n=108) and control arm (n=108). Participants’ socio-demographic information was obtained using the widely validated WHO STEPwise questionnaire, and a selfdeveloped questionnaire, including previously validated measurement scales were used to obtain information on adherence, self-management behaviour, self-efficacy and health-related quality of life. Participants in the intervention arm received daily text messages related to diabetes management and care for six months. Data were collected at baseline and six months post-intervention. Blood glucose, blood pressure and anthropometric measurements followed standard procedure. Mixed-model analysis was used to assess the impact of the SMS on random blood glucose while xi | P a g e linear and bivariate logistic regression were used to assess for effect on other clinical outcomes. Results: The mean age of the participants was 60.64 (SD± 11.58) years. The majority of the study participants had secondary level of education (95.3%) and earned 1500 to 14200 Rand per month (67.7%). For both the intervention and the control group, majority never used tobacco (98.10% vs 94.40%) or alcohol (88.00% vs 87.00%). Both arms of the study showed improvement in the primary outcome (blood glucose level), with no significant difference, the mean adjusted difference in blood glucose from baseline to six months post-intervention was 0.26 (-0.81 to 1.32), p=0.634. Also, the intervention did not have a significant effect on the secondary outcomes (knowledge, medication adherence, dietary adherence, adherence to physical activity, healthrelated quality of life, self-management behaviour and diabetes distress). Similarly, the intervention did not have any significant effect on secondary clinical outcomes such as weight (p=0.654), body mass index (p=0.439), systolic (p=0.610) and diastolic blood pressure (p=0.535). An overwhelming majority of the participants (90.74%) were pleased with the intervention and felt it was helpful. Of those who took part in the intervention, 91% completed the follow-up study after six months. Conclusion: The use of SMS is a highly acceptable and feasible adjunct to standard clinical care in the promotion of health among diabetic patients in this study setting. Although there was a little improvement, the efficacy of a unidirectional text messaging in promoting health outcomes in this study setting is still doubt
- Full Text:
- Date Issued: 2019
Challenges of the primigravida’s in accessing antenatal care early and regularly in Buffalo city Metropolitan Municipality, Eastern Cape Province, South Africa
- Seakamela, Khomotso Precious
- Authors: Seakamela, Khomotso Precious
- Date: 2019
- Subjects: Maternal health services Prenatal care
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/16803 , vital:40775
- Description: According to National Department of Health (NDOH National :2015), antenatal care is free in South Africa’s public health system and nearly all pregnant women and girls attend an antenatal clinic at least once during their pregnancy. However, most pregnant women do not access antenatal care until the later stage of pregnancy. Such delays have been linked to nearly a quarter of avoidable maternal deaths in South Africa. According to World Health Organisation (WHO, 2016; 11), maternal mortality and morbidity are some of the most important global health issues facing the world today. Worldwide, approximately 1000 women die each day from pregnancy and childbirth related causes (WHO, 2016; 11). In addition, 99% of these maternal deaths occur in the developing world, with sub-Saharan Africa accounting for over half of these deaths. The international community has committed to improving maternal health by 2015 with Millennium Development Goal (MDG) number five, which aimed to reduce maternal mortality by three quarters and reach universal access to reproductive health care (www.worldbank.org/mdgs/). Even with this commitment, many countries like South Africa have failed to implement effective programs to reduce maternal mortality and morbidity, and women around the world continue to die and suffer from the complications of pregnancy and childbirth. According to NDOH (2015; 2), women who suspect that they might be pregnant should schedule a booking and visit to their clinic and begin antenatal care as soon as possible. These visits include a physical examination, which includes blood pressure checks, weight checks, providing a urine sample, testing for sexually transmitted infections and checking for tuberculosis. Depending on the stage of the pregnancy, healthcare providers may also do blood tests and examination, which includes an ultrasound. The purpose of the study was to to investigate the challenges of Primigravida’s in accessing antenatal care early and regularly in Buffalo City Metropolitan (BCM) and to assist in formulating recommendations for improving factors that are perceived as obstacles to the utilisation of antenatal care services in the BCM District. vii The study was conducted in five facilities at BCM (Dimbaza Community Health Centre, Empilweni Gompo Clinic, Moore Street Clinic, Central Clinic and Notyatyambo Clinic). BCM is one of the seven districts of Eastern Cape Province of South Africa. The seat of BCM is East London. The data was collected using cross-sectional, self-administered questionnaires that were conducted in selected health facilities of Buffalo City Metropolitan. In this study, the population consisted of primigravida’s between the ages of 18-35 who start clinic attendance in the second trimester of pregnancy at five facilities, Buffalo City Metropolitan. Findings: The biggest challenges, as expressed by the participants, were lack of money, unsuitable clinic times, work commitments, delays at clinic and family control. Most of the participants had good experiences of antenatal care. The timing of antenatal clinic attendance is not influenced by age, education, residential zone, employment status and proximity of clinic
- Full Text:
- Date Issued: 2019
- Authors: Seakamela, Khomotso Precious
- Date: 2019
- Subjects: Maternal health services Prenatal care
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/16803 , vital:40775
- Description: According to National Department of Health (NDOH National :2015), antenatal care is free in South Africa’s public health system and nearly all pregnant women and girls attend an antenatal clinic at least once during their pregnancy. However, most pregnant women do not access antenatal care until the later stage of pregnancy. Such delays have been linked to nearly a quarter of avoidable maternal deaths in South Africa. According to World Health Organisation (WHO, 2016; 11), maternal mortality and morbidity are some of the most important global health issues facing the world today. Worldwide, approximately 1000 women die each day from pregnancy and childbirth related causes (WHO, 2016; 11). In addition, 99% of these maternal deaths occur in the developing world, with sub-Saharan Africa accounting for over half of these deaths. The international community has committed to improving maternal health by 2015 with Millennium Development Goal (MDG) number five, which aimed to reduce maternal mortality by three quarters and reach universal access to reproductive health care (www.worldbank.org/mdgs/). Even with this commitment, many countries like South Africa have failed to implement effective programs to reduce maternal mortality and morbidity, and women around the world continue to die and suffer from the complications of pregnancy and childbirth. According to NDOH (2015; 2), women who suspect that they might be pregnant should schedule a booking and visit to their clinic and begin antenatal care as soon as possible. These visits include a physical examination, which includes blood pressure checks, weight checks, providing a urine sample, testing for sexually transmitted infections and checking for tuberculosis. Depending on the stage of the pregnancy, healthcare providers may also do blood tests and examination, which includes an ultrasound. The purpose of the study was to to investigate the challenges of Primigravida’s in accessing antenatal care early and regularly in Buffalo City Metropolitan (BCM) and to assist in formulating recommendations for improving factors that are perceived as obstacles to the utilisation of antenatal care services in the BCM District. vii The study was conducted in five facilities at BCM (Dimbaza Community Health Centre, Empilweni Gompo Clinic, Moore Street Clinic, Central Clinic and Notyatyambo Clinic). BCM is one of the seven districts of Eastern Cape Province of South Africa. The seat of BCM is East London. The data was collected using cross-sectional, self-administered questionnaires that were conducted in selected health facilities of Buffalo City Metropolitan. In this study, the population consisted of primigravida’s between the ages of 18-35 who start clinic attendance in the second trimester of pregnancy at five facilities, Buffalo City Metropolitan. Findings: The biggest challenges, as expressed by the participants, were lack of money, unsuitable clinic times, work commitments, delays at clinic and family control. Most of the participants had good experiences of antenatal care. The timing of antenatal clinic attendance is not influenced by age, education, residential zone, employment status and proximity of clinic
- Full Text:
- Date Issued: 2019
Antihypertensive effects of the hydroethanol extract of Senecio serratuloides DC in rats
- Tata, Charlotte Mungho, Sewani-Rusike, Constance Rufaro, Oyedeji, Opeoluwa Oyehan, Gwebu, Ephraim Tobela, Mahlakata, Fikile, Nkeh-Chungag, Benedicta Ngwenchi
- Authors: Tata, Charlotte Mungho , Sewani-Rusike, Constance Rufaro , Oyedeji, Opeoluwa Oyehan , Gwebu, Ephraim Tobela , Mahlakata, Fikile , Nkeh-Chungag, Benedicta Ngwenchi
- Date: 2019
- Subjects: South Africa Hypertension Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5842 , vital:44654 , https://doi.org/10.1186/s12906-019-2463-2
- Description: Senecio serratuloides DC is used in folk medicine for treating hypertension, skin disorders, internal and external sores, rashes, burns and wounds. This study aimed at investigating the antihypertensive effects of the hydroethanol extract of S. serratuloides (HESS) in N-Nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. Methods: Acute toxicity of HESS was first determined to provide guidance on doses to be used in this study. Lorke’s method was used to determine safety of the extract in mice. Female Wistar rats were treated orally once daily with L-NAME (40 mg/kg) for 4 weeks and then concomitantly with L-NAME (20 mg/kg) and plant extract (150 and 300 mg/kg), captopril (20 mg/kg) or saline as per assigned group for 2 weeks followed by a 2-week period of assigned treatments only. Blood pressure was monitored weekly. Lipid profile, nitric oxide, renin and angiotensin II concentrations were determined in serum while mineralocorticoid receptor concentration was quantified in the kidney homogenate. Nitric oxide (NO) concentration was determined in serum and cardiac histology performed. Results HESS was found to be non-toxic, having a LD50 greater than 5000 mg/kg. Blood pressure increased progressively in all animals from the second week of L-NAME treatment. HESS treatment significantly and dose-dependently lowered systolic blood pressure (p less 0.001), diastolic blood pressure (p less 0.01), low density lipoprotein cholesterol (p less 0.01) and triglycerides (p less 0.01). It significantly prevented L-NAME induced decrease in serum angiotensin II (p less 0.01), high density lipoprotein cholesterol (p less 0.001) and serum nitric oxide concentrations (p less 0.001). HESS also significantly (p less 0.01) prevented collagen deposition in cardiac tissue. Conclusion The hydro-ethanol extract of Senecio serratuloides showed antihypertensive, antihyperlipidemic and cardioprotective effects in rats thus confirming its usefulness in traditional antihypertensive therapy and potential for antihypertensive drug development.
- Full Text:
- Date Issued: 2019
- Authors: Tata, Charlotte Mungho , Sewani-Rusike, Constance Rufaro , Oyedeji, Opeoluwa Oyehan , Gwebu, Ephraim Tobela , Mahlakata, Fikile , Nkeh-Chungag, Benedicta Ngwenchi
- Date: 2019
- Subjects: South Africa Hypertension Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5842 , vital:44654 , https://doi.org/10.1186/s12906-019-2463-2
- Description: Senecio serratuloides DC is used in folk medicine for treating hypertension, skin disorders, internal and external sores, rashes, burns and wounds. This study aimed at investigating the antihypertensive effects of the hydroethanol extract of S. serratuloides (HESS) in N-Nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. Methods: Acute toxicity of HESS was first determined to provide guidance on doses to be used in this study. Lorke’s method was used to determine safety of the extract in mice. Female Wistar rats were treated orally once daily with L-NAME (40 mg/kg) for 4 weeks and then concomitantly with L-NAME (20 mg/kg) and plant extract (150 and 300 mg/kg), captopril (20 mg/kg) or saline as per assigned group for 2 weeks followed by a 2-week period of assigned treatments only. Blood pressure was monitored weekly. Lipid profile, nitric oxide, renin and angiotensin II concentrations were determined in serum while mineralocorticoid receptor concentration was quantified in the kidney homogenate. Nitric oxide (NO) concentration was determined in serum and cardiac histology performed. Results HESS was found to be non-toxic, having a LD50 greater than 5000 mg/kg. Blood pressure increased progressively in all animals from the second week of L-NAME treatment. HESS treatment significantly and dose-dependently lowered systolic blood pressure (p less 0.001), diastolic blood pressure (p less 0.01), low density lipoprotein cholesterol (p less 0.01) and triglycerides (p less 0.01). It significantly prevented L-NAME induced decrease in serum angiotensin II (p less 0.01), high density lipoprotein cholesterol (p less 0.001) and serum nitric oxide concentrations (p less 0.001). HESS also significantly (p less 0.01) prevented collagen deposition in cardiac tissue. Conclusion The hydro-ethanol extract of Senecio serratuloides showed antihypertensive, antihyperlipidemic and cardioprotective effects in rats thus confirming its usefulness in traditional antihypertensive therapy and potential for antihypertensive drug development.
- Full Text:
- Date Issued: 2019
Resilience towards adverse childhood experiences among public secondary school students in Alice, South Africa
- Authors: Obisesan , Matthew Tobiloba
- Date: 2019
- Subjects: Child development Child psychology
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/16769 , vital:40772
- Description: Adverse childhood experiences (ACEs) are of great concerns in public health. They are traumatic experiences that occur during childhood. ACEs include various forms of abuse and maltreatment which can be emotional, physical, verbal and sexual, different degrees of household dysfunction such as growing up with substance abuse like drugs and alcohol, witnessing domestic violence, mental illnesses, crime in the home and parental disharmony. Although childhood adversities and traumatic experiences occur before the individual is 18 years of age, the effects of such experiences can last a lifetime causing mental and chronic medical illnesses. Resilience is perceived as an antidote to the detrimental effect of ACEs. It is a situation in which an individual displays a high level of effectiveness after a significant misfortune or adversity. This study was conducted to assess the level of resilience towards adverse childhood experiences among public secondary school children in Alice. Data were collected with the aid of a wellstructured questionnaire from 418 public high school students using Convenience sampling method. Factors influencing resilience among the learners were examined. Consequently, the data collected were analyzed using descriptive statistics and ordered logit regression model. From the results, it is observed that the majority of the learners live with their grandparents and the most prevalent form of ACEs is emotional abuse, followed by sexual abuse while community violence is the least common childhood adversity. This study further reveals that some of the respondents experienced more than one form of adverse childhood experience. In addition, irrespective of what the students have been through, they are largely observed to be resilient. Analysis from the ordered logit regression model shows that age, class in school, gender, religion, race and who the student lives with are significantly related to resilience. The study, therefore, recommends a functional counseling unit in the schools while student-teacher relationship must be encouraged
- Full Text:
- Date Issued: 2019
- Authors: Obisesan , Matthew Tobiloba
- Date: 2019
- Subjects: Child development Child psychology
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/16769 , vital:40772
- Description: Adverse childhood experiences (ACEs) are of great concerns in public health. They are traumatic experiences that occur during childhood. ACEs include various forms of abuse and maltreatment which can be emotional, physical, verbal and sexual, different degrees of household dysfunction such as growing up with substance abuse like drugs and alcohol, witnessing domestic violence, mental illnesses, crime in the home and parental disharmony. Although childhood adversities and traumatic experiences occur before the individual is 18 years of age, the effects of such experiences can last a lifetime causing mental and chronic medical illnesses. Resilience is perceived as an antidote to the detrimental effect of ACEs. It is a situation in which an individual displays a high level of effectiveness after a significant misfortune or adversity. This study was conducted to assess the level of resilience towards adverse childhood experiences among public secondary school children in Alice. Data were collected with the aid of a wellstructured questionnaire from 418 public high school students using Convenience sampling method. Factors influencing resilience among the learners were examined. Consequently, the data collected were analyzed using descriptive statistics and ordered logit regression model. From the results, it is observed that the majority of the learners live with their grandparents and the most prevalent form of ACEs is emotional abuse, followed by sexual abuse while community violence is the least common childhood adversity. This study further reveals that some of the respondents experienced more than one form of adverse childhood experience. In addition, irrespective of what the students have been through, they are largely observed to be resilient. Analysis from the ordered logit regression model shows that age, class in school, gender, religion, race and who the student lives with are significantly related to resilience. The study, therefore, recommends a functional counseling unit in the schools while student-teacher relationship must be encouraged
- Full Text:
- Date Issued: 2019
Managing personal archives in specialised repositories: a case study of Phillip Valentine Tobias collection(s) at the university of the Witwatersrand
- Authors: Marima, Elizabeth Nakai
- Date: 2019
- Subjects: Archives management Institutional repositories
- Language: English
- Type: Thesis , Masters , M LIS
- Identifier: http://hdl.handle.net/10353/11473 , vital:39075
- Description: Personal archives are noncurrent records created by individuals that are selected and kept for their enduring value. They are a record of the past and stand as evidence of what transpired. They make part of repository holdings together with public archives in organisational repositories. Public archives document transactions, statutes, procedures, and regulations. Personal archives contain the documentation of individual lives, emotions, values, experiences and human personality. They seek to reflect the character of the individual who created them. Management of personal archives in repositories refers to their acquisition, collection, arrangement, description, preservation, conservation, creation if access and use. Therefore, the main purpose of this study is to investigate the managing of personal archives in specialized repositories: A case study of Phillip Valentine Tobias Collection(s) at the University of the Witwatersrand, Johannesburg. The study sought to investigate the legal framework that regulates managing of personal archives and the experiences, perceptions and expectations of people managing the personal archives. Furthermore, the study sought to identify strategies of improving the management of personal archives at University of the Witwatersrand, Johannesburg. The study was motivated by the archival theory that conceptualizes grouping of records together for their content and contextual value as evidence with the aim of restating the past. The theory further defines personal archives as records of continued value created by an individual which accumulated naturally, impartially and without prejudice in order to accurately witness the past. The study used a qualitative methodology and was guided by the interpretivist research paradigm. Data was collected using open-ended questions to conduct semi-structured interviews. To complement data, a document analysis, focus group and casual observation were also used. The site of study was University of the Witwatersrand. The total population constituted 41 staff members working in six special repositories with the Phillip Tobias collections at University of the Witwatersrand. The sample size was 25 staff members working in three special repositories. The qualitative data was reported verbartim and the Constant Comparative method was used for data analysis. The findings indicated challenges to the archival theory as the contextual grouping of personal archives was distorted. The study also showed that the archives were xv mismanaged due to framework irregularities, lack of top management support and limited resources. The major resources that were limited were infrastructure, archival ICT systems, human resources and training needs. From the interviews, the research identified strategies of improving the management of personal archives. The study recommended that the university benchmark for archival support strategies and to also engage in existence justification initiatives to harness top management’s attention towards the archive. Out of the identified strategies, the study suggested a tailor made strategy, which combined aspects of each strategy in order to avoid associated challenges.
- Full Text:
- Date Issued: 2019
- Authors: Marima, Elizabeth Nakai
- Date: 2019
- Subjects: Archives management Institutional repositories
- Language: English
- Type: Thesis , Masters , M LIS
- Identifier: http://hdl.handle.net/10353/11473 , vital:39075
- Description: Personal archives are noncurrent records created by individuals that are selected and kept for their enduring value. They are a record of the past and stand as evidence of what transpired. They make part of repository holdings together with public archives in organisational repositories. Public archives document transactions, statutes, procedures, and regulations. Personal archives contain the documentation of individual lives, emotions, values, experiences and human personality. They seek to reflect the character of the individual who created them. Management of personal archives in repositories refers to their acquisition, collection, arrangement, description, preservation, conservation, creation if access and use. Therefore, the main purpose of this study is to investigate the managing of personal archives in specialized repositories: A case study of Phillip Valentine Tobias Collection(s) at the University of the Witwatersrand, Johannesburg. The study sought to investigate the legal framework that regulates managing of personal archives and the experiences, perceptions and expectations of people managing the personal archives. Furthermore, the study sought to identify strategies of improving the management of personal archives at University of the Witwatersrand, Johannesburg. The study was motivated by the archival theory that conceptualizes grouping of records together for their content and contextual value as evidence with the aim of restating the past. The theory further defines personal archives as records of continued value created by an individual which accumulated naturally, impartially and without prejudice in order to accurately witness the past. The study used a qualitative methodology and was guided by the interpretivist research paradigm. Data was collected using open-ended questions to conduct semi-structured interviews. To complement data, a document analysis, focus group and casual observation were also used. The site of study was University of the Witwatersrand. The total population constituted 41 staff members working in six special repositories with the Phillip Tobias collections at University of the Witwatersrand. The sample size was 25 staff members working in three special repositories. The qualitative data was reported verbartim and the Constant Comparative method was used for data analysis. The findings indicated challenges to the archival theory as the contextual grouping of personal archives was distorted. The study also showed that the archives were xv mismanaged due to framework irregularities, lack of top management support and limited resources. The major resources that were limited were infrastructure, archival ICT systems, human resources and training needs. From the interviews, the research identified strategies of improving the management of personal archives. The study recommended that the university benchmark for archival support strategies and to also engage in existence justification initiatives to harness top management’s attention towards the archive. Out of the identified strategies, the study suggested a tailor made strategy, which combined aspects of each strategy in order to avoid associated challenges.
- Full Text:
- Date Issued: 2019
The morphotactic constraints of verbal extensions in isiXhosa
- Authors: Mkabile, Hlumela
- Date: 2019
- Subjects: Xhosa language -- Grammar
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92849 , vital:30749
- Description: Bantu verbal suffixes, also known as extensions, follow a rather rigid pattern when they attach to the verb. Studies (e.g. Hyman 2002, Good 2005, 2007, among others) have shown that the order followed by these extensions is: Causative, Applicative, Reciprocal, Passive (CARP). Although this pattern is widespread across Bantu, some variations in the ordering of these extensions have been observed in some languages (Kathupa 1991, Simango 1995, Sibanda 2004, among others), which suggests that the template is not as rigid as one might think. This study investigated the morphotactic constraints between four verbal extensions in isiXhosa, the Causative, Applicative, Reciprocal and Passive. It focused on the morphotactics of the transitivising extensions (Causative and Applicative) in the first instance, and morphotactics of the detransitivising extensions (Reciprocal and Passive) in the second instance. The study found that although the co-occurrence of causatives and applicatives is a regular feature in Bantu languages, isiXhosa has restrictions on the co-occurrence of these extensions on some verbs. The study also found that although Causative-Applicative is the expected order the language permits Applicative-Causative in certain contexts. With respect to the detransitivising extensions, the study revealed that there are limited contexts in which these extensions co-occur and, crucially, that these extensions are freely ordered in the language.
- Full Text:
- Date Issued: 2019
- Authors: Mkabile, Hlumela
- Date: 2019
- Subjects: Xhosa language -- Grammar
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92849 , vital:30749
- Description: Bantu verbal suffixes, also known as extensions, follow a rather rigid pattern when they attach to the verb. Studies (e.g. Hyman 2002, Good 2005, 2007, among others) have shown that the order followed by these extensions is: Causative, Applicative, Reciprocal, Passive (CARP). Although this pattern is widespread across Bantu, some variations in the ordering of these extensions have been observed in some languages (Kathupa 1991, Simango 1995, Sibanda 2004, among others), which suggests that the template is not as rigid as one might think. This study investigated the morphotactic constraints between four verbal extensions in isiXhosa, the Causative, Applicative, Reciprocal and Passive. It focused on the morphotactics of the transitivising extensions (Causative and Applicative) in the first instance, and morphotactics of the detransitivising extensions (Reciprocal and Passive) in the second instance. The study found that although the co-occurrence of causatives and applicatives is a regular feature in Bantu languages, isiXhosa has restrictions on the co-occurrence of these extensions on some verbs. The study also found that although Causative-Applicative is the expected order the language permits Applicative-Causative in certain contexts. With respect to the detransitivising extensions, the study revealed that there are limited contexts in which these extensions co-occur and, crucially, that these extensions are freely ordered in the language.
- Full Text:
- Date Issued: 2019
BODIPY and porphyrin dyes for direct glucose sensing and optical limiting applications
- Authors: Ndebele, Nobuhle
- Date: 2019
- Subjects: Boron compounds , Boric acid , Porphyrins , Dyes and dying -- Chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97221 , vital:31412
- Description: A series of BODIPY dyes functionalised with boronic acid in the 3,5-positions were successfully synthesised and characterised by using various analytical techniques. The dyes were prepared through a slight modification of the conventional acid catalysed condensation method. Phenylboronic acid moieties were added as styryl groups at the 3,5-positions of the 1,3,5,7-tetrametylBODIPY cores using a modified Knoevengal condensation method. The addition of the styryls resulted in the main absorption band of the dyes red-shifting to the 630−650 nm region. The photophysical and electrochemical properties of these dyes were studied to determine whether the dyes are suitable for use in the fluorescent, colourimetric and electrochemical detection of glucose. Boronic acid moieties were added as bioreceptor recognition elements because they have an affinity for carbohydrates and therefore would be able to bind and “detect” glucose. The series of BODIPY dyes did not show a “turn-on” fluorescence effect upon addition with glucose at the physiological pH. This was attributed on the basis of molecular modelling to the absence of an MO localised on the boronic-acid-substituted styryl moieties that lie close in energy to the HOMO and LUMO that facilitates the formation of an intramolecular charge transfer state. However, colourimetric changes that are visible to the naked eye are observed at basic pH when glucose was added to the dye solutions. The dyes exhibited favourable electrochemical behaviour and were able to detect glucose directly in this context when glassy carbon electrodes are modified through the drop dry method. A series of Sn(IV) porphyrins with thienyl and phenyl groups at the meso-positions were successfully synthesised and characterised. Pyridine and tetrabutyl axial ligands were added to the porphyrins to limit aggregation. The optical limiting properties of these porphyrins and three styrylated BODIPY dyes were studied in benzene and dichloromethane. Dyes were also embedded in polystyrene and studied as thin films to further gauge their suitability for use in optical limiting applications. Second-order hyperpolarizability, third-order susceptibly, non-linear absorption with reversible saturable absorption and the optical limiting threshold, were the parameters studied. Three of the four porphyrins and the three styrylated BODIPY dyes showed favourable optical limiting behaviour, which was further enhanced when the dyes are embedded in polymer thin films.
- Full Text:
- Date Issued: 2019
- Authors: Ndebele, Nobuhle
- Date: 2019
- Subjects: Boron compounds , Boric acid , Porphyrins , Dyes and dying -- Chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97221 , vital:31412
- Description: A series of BODIPY dyes functionalised with boronic acid in the 3,5-positions were successfully synthesised and characterised by using various analytical techniques. The dyes were prepared through a slight modification of the conventional acid catalysed condensation method. Phenylboronic acid moieties were added as styryl groups at the 3,5-positions of the 1,3,5,7-tetrametylBODIPY cores using a modified Knoevengal condensation method. The addition of the styryls resulted in the main absorption band of the dyes red-shifting to the 630−650 nm region. The photophysical and electrochemical properties of these dyes were studied to determine whether the dyes are suitable for use in the fluorescent, colourimetric and electrochemical detection of glucose. Boronic acid moieties were added as bioreceptor recognition elements because they have an affinity for carbohydrates and therefore would be able to bind and “detect” glucose. The series of BODIPY dyes did not show a “turn-on” fluorescence effect upon addition with glucose at the physiological pH. This was attributed on the basis of molecular modelling to the absence of an MO localised on the boronic-acid-substituted styryl moieties that lie close in energy to the HOMO and LUMO that facilitates the formation of an intramolecular charge transfer state. However, colourimetric changes that are visible to the naked eye are observed at basic pH when glucose was added to the dye solutions. The dyes exhibited favourable electrochemical behaviour and were able to detect glucose directly in this context when glassy carbon electrodes are modified through the drop dry method. A series of Sn(IV) porphyrins with thienyl and phenyl groups at the meso-positions were successfully synthesised and characterised. Pyridine and tetrabutyl axial ligands were added to the porphyrins to limit aggregation. The optical limiting properties of these porphyrins and three styrylated BODIPY dyes were studied in benzene and dichloromethane. Dyes were also embedded in polystyrene and studied as thin films to further gauge their suitability for use in optical limiting applications. Second-order hyperpolarizability, third-order susceptibly, non-linear absorption with reversible saturable absorption and the optical limiting threshold, were the parameters studied. Three of the four porphyrins and the three styrylated BODIPY dyes showed favourable optical limiting behaviour, which was further enhanced when the dyes are embedded in polymer thin films.
- Full Text:
- Date Issued: 2019
Descriptive guidelines for mediation to enhance the parental involvement of unmarried fathers
- Authors: Nordien-Lagardien, Razia
- Date: 2019
- Subjects: Mediation , Unmarried fathers -- South Africa Father and child -- South Africa Unmarried mothers -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/30462 , vital:30948
- Description: A significant change brought about by the Children’s Act 38 of 2005 (RSA, 2006), is that of the status of unmarried fathers. The parental rights of unmarried fathers have evolved in South Africa, especially since the Children’s Act 38 of 2005 (RSA, 2006) now recognises that unmarried fathers should have inherent right of contact, guardianship and care. These rights are, however, not automatic and need to be acquired through a process of mediation. While this legislation aims to facilitate the parental involvement of fathers by giving them rights as per Section 21 of the Children’s Act 38 of 2005 (RSA, 2006), the reality is that many unmarried fathers still remain challenged in this regard despite the change in their legal position as fathers. Unmarried fathers are often compelled to take the matter further through protracted court processes. Unmarried fathers face unique challenges with parental involvement after separation and they often need to negotiate their involvement with the mother after separation. Given that mediation between unmarried parents is in its infancy in South Africa, very little research has been done in this area. It was envisaged that this study would highlight the important aspects of mediation which need to be considered in order for mediation outcomes to be more successful and to enhance the co-parenting relationship. The study employed a qualitative research approach that was exploratory, descriptive and contextual in design. The research study consisted of three phases. Phase 1 employed a multiple case study design in order to develop an understanding of the experiences and perceptions of unmarried fathers and mothers, as well as mediators, regarding the parental responsibilities of unmarried fathers in addition to their experiences of mediation. The data collection process comprised in-depth semi-structured interviews with three sample groups, namely unmarried fathers, and mothers, and mediators. The data collected from the interviews were transcribed, coded and analysed by the researcher through the use of two techniques, namely: within-case analysis and cross-case synthesis. An independent coder was utilised to verify the coding and analysis process. The analysis of the data in Phase 1 revealed that the construction of the role of unmarried fathers is influenced by various factors such as cultural and religious influences; childhood experiences of fatherhood; societal constructions of the father’s role, and the perception of the legal rights of unmarried fathers. The new legislation pertaining to the responsibilities and rights of unmarried fathers, as contained in the Children’s Act 38 of 2005 (RSA, 2006), has resulted in increased parental conflict between parents after separation owing to their lack of awareness and confusion regarding the changes in legislation pertaining to the rights of unmarried fathers and the role of customary law in this regard. This has resulted in misconceptions about the legal rights of unmarried fathers, which have influenced unmarried parents’ attitudes and receptiveness to mediation. A significant barrier to father involvement emanating from the findings was relationship conflict experienced after separation, which was also identified as a significant challenge in mediation. The discussion of the themes reflected both positive and negative experiences of mediation for the study participants. While the parents derived educational and therapeutic benefits from mediation; there were also several factors such as relationship conflict, cultural barriers, influences of the extended family, and the approach and skills of the mediator, which influenced the mediation process. In Phase 2 of the study an integrative literature review and synthesis of the literature was conducted and critically appraised in terms of emergent themes and relevant research in the area of family mediation, which would inform the process of developing the descriptive guidelines for mediation with unmarried parents. The empirical findings from the study were synthesised with the findings from the integrative literature review, thus enabling conclusions to be drawn in order to generate descriptive guidelines for mediation. Phase 3 of the study describes the guidelines for mediation which emanated from the synthesis of the findings in Phase 1 and Phase 2 of the study. As part of a qualitative evaluation, the guidelines were presented to an expert panel for review, after which the guidelines were finalised. The proposed guidelines for mediation to enhance the parental involvement of unmarried fathers is based on the hybrid model of mediation, which incorporates elements from the Transformative approach, the African centred approach and the co-mediation model. The guidelines are further described in terms of a phased approach to mediation.
- Full Text:
- Date Issued: 2019
- Authors: Nordien-Lagardien, Razia
- Date: 2019
- Subjects: Mediation , Unmarried fathers -- South Africa Father and child -- South Africa Unmarried mothers -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/30462 , vital:30948
- Description: A significant change brought about by the Children’s Act 38 of 2005 (RSA, 2006), is that of the status of unmarried fathers. The parental rights of unmarried fathers have evolved in South Africa, especially since the Children’s Act 38 of 2005 (RSA, 2006) now recognises that unmarried fathers should have inherent right of contact, guardianship and care. These rights are, however, not automatic and need to be acquired through a process of mediation. While this legislation aims to facilitate the parental involvement of fathers by giving them rights as per Section 21 of the Children’s Act 38 of 2005 (RSA, 2006), the reality is that many unmarried fathers still remain challenged in this regard despite the change in their legal position as fathers. Unmarried fathers are often compelled to take the matter further through protracted court processes. Unmarried fathers face unique challenges with parental involvement after separation and they often need to negotiate their involvement with the mother after separation. Given that mediation between unmarried parents is in its infancy in South Africa, very little research has been done in this area. It was envisaged that this study would highlight the important aspects of mediation which need to be considered in order for mediation outcomes to be more successful and to enhance the co-parenting relationship. The study employed a qualitative research approach that was exploratory, descriptive and contextual in design. The research study consisted of three phases. Phase 1 employed a multiple case study design in order to develop an understanding of the experiences and perceptions of unmarried fathers and mothers, as well as mediators, regarding the parental responsibilities of unmarried fathers in addition to their experiences of mediation. The data collection process comprised in-depth semi-structured interviews with three sample groups, namely unmarried fathers, and mothers, and mediators. The data collected from the interviews were transcribed, coded and analysed by the researcher through the use of two techniques, namely: within-case analysis and cross-case synthesis. An independent coder was utilised to verify the coding and analysis process. The analysis of the data in Phase 1 revealed that the construction of the role of unmarried fathers is influenced by various factors such as cultural and religious influences; childhood experiences of fatherhood; societal constructions of the father’s role, and the perception of the legal rights of unmarried fathers. The new legislation pertaining to the responsibilities and rights of unmarried fathers, as contained in the Children’s Act 38 of 2005 (RSA, 2006), has resulted in increased parental conflict between parents after separation owing to their lack of awareness and confusion regarding the changes in legislation pertaining to the rights of unmarried fathers and the role of customary law in this regard. This has resulted in misconceptions about the legal rights of unmarried fathers, which have influenced unmarried parents’ attitudes and receptiveness to mediation. A significant barrier to father involvement emanating from the findings was relationship conflict experienced after separation, which was also identified as a significant challenge in mediation. The discussion of the themes reflected both positive and negative experiences of mediation for the study participants. While the parents derived educational and therapeutic benefits from mediation; there were also several factors such as relationship conflict, cultural barriers, influences of the extended family, and the approach and skills of the mediator, which influenced the mediation process. In Phase 2 of the study an integrative literature review and synthesis of the literature was conducted and critically appraised in terms of emergent themes and relevant research in the area of family mediation, which would inform the process of developing the descriptive guidelines for mediation with unmarried parents. The empirical findings from the study were synthesised with the findings from the integrative literature review, thus enabling conclusions to be drawn in order to generate descriptive guidelines for mediation. Phase 3 of the study describes the guidelines for mediation which emanated from the synthesis of the findings in Phase 1 and Phase 2 of the study. As part of a qualitative evaluation, the guidelines were presented to an expert panel for review, after which the guidelines were finalised. The proposed guidelines for mediation to enhance the parental involvement of unmarried fathers is based on the hybrid model of mediation, which incorporates elements from the Transformative approach, the African centred approach and the co-mediation model. The guidelines are further described in terms of a phased approach to mediation.
- Full Text:
- Date Issued: 2019
Development and characterisation of miconazole nitrate loaded solid lipid nanoparticles for incorporation into a vaginal mucoadhesive system
- Authors: Gwimo, Wimana Alexis
- Date: 2019
- Subjects: Vaginitis , Vagina -- Diseases Sexually transmitted diseases -- Diagnosis Sexually transmitted diseases -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39632 , vital:35335
- Description: Vulvovaginal candidiasis (VVC) is the second most common cause of vaginitis, affecting 75% of women of sexual maturity. The prescribed first line treatment involves the use of locally-acting imidazole creams. These conventional dosage forms possess limitations, such as leakage, messiness and low residence time at the site of application; all which promote poor patient adherence to pharmacotherapy. Poor adherence is then attributed to increased incidence of VVC reoccurrence and the emergence of Candida strains. It was, therefore, speculated that through the use of novel drug delivery systems (NDDS), the pharmacokinetic and antimicrobial characteristics of a model antifungal drug (miconazole nitrate [MNZ]) could be improved. Primary aim: To develop, optimise and characterise a mucoadhesive hydrogel incorporated with MNZ loaded solid lipid nanoparticles (MNZ-SLNs) for the intended treatment of VVC. This study was conducted in three phases, viz. pre-formulation studies, development, optimisation and characterisation of MNZ-SLNs, and the development and characterisation of MNZ-SLN-loaded thermoresponsive hydrogel. An alternative method for the quantification of MNZ was developed through the use of an octyl stationary phase. The method was deemed suitable for its intended use with a linear equation of y = 811214x + 67958 and a respective limit of quantitation (LoQ) and detection of 0.015 mg/ml and 0.052 mg/ml. Differential scanning calorimetry (DSC) studies suggested that cholesterol showed great promise of facilitating high drug entrapment efficiency (EE). MNZ-SLNs were prepared by means of a novel melt- emulsification sonication and low temperature solidification method and optimised statistically by a 13-run-two-factor central composite rotatable design (CCRD). The predicted optimisation parameters were 4% m/v lipid concentration and 260.94 sonication time. Optimal MNZ-SLN formulations were prepared and characterised by means of photon correlation spectroscopy (PCS), transmission electron microscopy (TEM) and centrifugation. PCS revealed uniform particles with a narrow polydispersity index (PDI) and a mean hydrodynamic diameter (z-avg.) of 73.03 nm and zeta potential (ZP) of 38.43 mV. Percent EE was calculated via an indirect method as 75.24%. Furthermore, the MNZ -SLNs were incorporated into a mucoadhesive thermo-responsive hydrogel with a sol-gel transition temperature of 33.33 ± 2.82 °C. In vitro drug release testing (IVDRT) was undertaken with the aid of a Franz diffusion vertical cell (FDVC) apparatus. A % cumulative drug release of 27.94% and 15.87% was obtained for MNZ- SLNs and MNZ-SLN hydrogels, respectively, after eight hours. The resultant data was fitted into various kinetic models with the aid of DDSolverTM (Microsoft Excel® add-ins, 2016) to evaluate which model attained the highest correlation co-efficient (r2). Both formulations attained high r2 of 0.9941 and 0.9945, respectively, with the Korsmeyer- Peppas mathematical model. A high diffusional exponent (n) of >1 was observed, suggesting a super case II drug release mechanism. Finally, a modified Kirby-Bauer disc diffusion assay was used for ascertaining Candida albicans susceptibility to the developed formulations. Controls in the form of unloaded preparations and a commercially available cream were used. MNZ-SLNs and MNZ-hydrogel demonstrated superior antifungal activity to the commercially available cream. These results indicate that the developed MNZ-SLNloaded hydrogel formulation with localised thermo-responsive effect may be a promising carrier for intravaginal delivery of MNZ in the treatment of VVC.
- Full Text:
- Date Issued: 2019
- Authors: Gwimo, Wimana Alexis
- Date: 2019
- Subjects: Vaginitis , Vagina -- Diseases Sexually transmitted diseases -- Diagnosis Sexually transmitted diseases -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39632 , vital:35335
- Description: Vulvovaginal candidiasis (VVC) is the second most common cause of vaginitis, affecting 75% of women of sexual maturity. The prescribed first line treatment involves the use of locally-acting imidazole creams. These conventional dosage forms possess limitations, such as leakage, messiness and low residence time at the site of application; all which promote poor patient adherence to pharmacotherapy. Poor adherence is then attributed to increased incidence of VVC reoccurrence and the emergence of Candida strains. It was, therefore, speculated that through the use of novel drug delivery systems (NDDS), the pharmacokinetic and antimicrobial characteristics of a model antifungal drug (miconazole nitrate [MNZ]) could be improved. Primary aim: To develop, optimise and characterise a mucoadhesive hydrogel incorporated with MNZ loaded solid lipid nanoparticles (MNZ-SLNs) for the intended treatment of VVC. This study was conducted in three phases, viz. pre-formulation studies, development, optimisation and characterisation of MNZ-SLNs, and the development and characterisation of MNZ-SLN-loaded thermoresponsive hydrogel. An alternative method for the quantification of MNZ was developed through the use of an octyl stationary phase. The method was deemed suitable for its intended use with a linear equation of y = 811214x + 67958 and a respective limit of quantitation (LoQ) and detection of 0.015 mg/ml and 0.052 mg/ml. Differential scanning calorimetry (DSC) studies suggested that cholesterol showed great promise of facilitating high drug entrapment efficiency (EE). MNZ-SLNs were prepared by means of a novel melt- emulsification sonication and low temperature solidification method and optimised statistically by a 13-run-two-factor central composite rotatable design (CCRD). The predicted optimisation parameters were 4% m/v lipid concentration and 260.94 sonication time. Optimal MNZ-SLN formulations were prepared and characterised by means of photon correlation spectroscopy (PCS), transmission electron microscopy (TEM) and centrifugation. PCS revealed uniform particles with a narrow polydispersity index (PDI) and a mean hydrodynamic diameter (z-avg.) of 73.03 nm and zeta potential (ZP) of 38.43 mV. Percent EE was calculated via an indirect method as 75.24%. Furthermore, the MNZ -SLNs were incorporated into a mucoadhesive thermo-responsive hydrogel with a sol-gel transition temperature of 33.33 ± 2.82 °C. In vitro drug release testing (IVDRT) was undertaken with the aid of a Franz diffusion vertical cell (FDVC) apparatus. A % cumulative drug release of 27.94% and 15.87% was obtained for MNZ- SLNs and MNZ-SLN hydrogels, respectively, after eight hours. The resultant data was fitted into various kinetic models with the aid of DDSolverTM (Microsoft Excel® add-ins, 2016) to evaluate which model attained the highest correlation co-efficient (r2). Both formulations attained high r2 of 0.9941 and 0.9945, respectively, with the Korsmeyer- Peppas mathematical model. A high diffusional exponent (n) of >1 was observed, suggesting a super case II drug release mechanism. Finally, a modified Kirby-Bauer disc diffusion assay was used for ascertaining Candida albicans susceptibility to the developed formulations. Controls in the form of unloaded preparations and a commercially available cream were used. MNZ-SLNs and MNZ-hydrogel demonstrated superior antifungal activity to the commercially available cream. These results indicate that the developed MNZ-SLNloaded hydrogel formulation with localised thermo-responsive effect may be a promising carrier for intravaginal delivery of MNZ in the treatment of VVC.
- Full Text:
- Date Issued: 2019
A strategy for improving the maturity levels of IT service management in higher education institutions in South Africa
- Authors: Hilmer, Thomas
- Date: 2019
- Subjects: Information technology -- Management , Information technology Education, Higher -- South Africa Education -- Effect of technological innovations on -- South Africa
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10948/40161 , vital:35824
- Description: IT Service Management (ITSM) refers to a set of activities that an organisation can perform to develop, supply, operate, manage and improve information technology related services in order to meet the needs of the business. The interest in ITSM is based on the expectation that applying best practice ITSM processes will result in lower expenses, fewer incidents and improved customer satisfaction. Various standards, frameworks, methodologies and processes have evolved to support this move to a value-driven, service-orientated approach to managing an organisation’s information systems. Between 2007 and 2009, Higher Education Institutions (HEIs) in South Africa benefited from a national project to improve the quality of their IT services through training in ITIL, a best practice ITSM framework. An assessment at the time, however, found that the maturity levels of the ITIL processes implemented after the intervention remained low, and this observation is common in other industries as well. The implementation of industry best practice ITSM frameworks does not always proceed smoothly; they can be costly, have long implementation times, and can be seen as excessively complicated and suited mainly for large organisations. Therefore, it is often challenging for organisations such as HEIs to improve their ITSM process maturity levels. The aim of this study is to develop a strategy that may assist South African HEIs in taking steps to improve their IT Service Management maturity levels. This primary research objective is addressed through a number of secondary research objectives, namely, to understand the challenges that HEIs often encounter when implementing ITSM; to determine the ITSM implementation status at a number of South African HEIs; to determine the various elements and components required to formulate the ITSM strategy; to determine whether alternatives to ITIL are feasible options for HEIs in South Africa; and to validate the proposed strategy by verifying its quality, utility and efficacy. A comprehensive literature review provides information on various ITSM standards, frameworks and methodologies. It also investigates ITSM adoption and implementation by organisations in general, and HEIs in particular, and how modern practices such as DevOps, Agile and Lean relate to ITSM. Thereafter, an online survey is used to determine the status of ITSM maturity levels at South African HEIs, and whether alternatives to ITIL are being used. Expert interviews are used to obtain additional information on what is required to formulate the proposed strategy. The findings from the literature review, survey and expert interviews are used to develop a four-step strategy, which was evaluated for its quality, utility and efficacy through an online assessment by the same experts. This strategy can be considered a useful tool for Higher Education Institutions in South Africa if they wish to increase their levels of IT Service Management maturity. The findings of this study make a substantial contribution to the field of ITSM research at South African Higher Education Institutions.
- Full Text:
- Date Issued: 2019
- Authors: Hilmer, Thomas
- Date: 2019
- Subjects: Information technology -- Management , Information technology Education, Higher -- South Africa Education -- Effect of technological innovations on -- South Africa
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10948/40161 , vital:35824
- Description: IT Service Management (ITSM) refers to a set of activities that an organisation can perform to develop, supply, operate, manage and improve information technology related services in order to meet the needs of the business. The interest in ITSM is based on the expectation that applying best practice ITSM processes will result in lower expenses, fewer incidents and improved customer satisfaction. Various standards, frameworks, methodologies and processes have evolved to support this move to a value-driven, service-orientated approach to managing an organisation’s information systems. Between 2007 and 2009, Higher Education Institutions (HEIs) in South Africa benefited from a national project to improve the quality of their IT services through training in ITIL, a best practice ITSM framework. An assessment at the time, however, found that the maturity levels of the ITIL processes implemented after the intervention remained low, and this observation is common in other industries as well. The implementation of industry best practice ITSM frameworks does not always proceed smoothly; they can be costly, have long implementation times, and can be seen as excessively complicated and suited mainly for large organisations. Therefore, it is often challenging for organisations such as HEIs to improve their ITSM process maturity levels. The aim of this study is to develop a strategy that may assist South African HEIs in taking steps to improve their IT Service Management maturity levels. This primary research objective is addressed through a number of secondary research objectives, namely, to understand the challenges that HEIs often encounter when implementing ITSM; to determine the ITSM implementation status at a number of South African HEIs; to determine the various elements and components required to formulate the ITSM strategy; to determine whether alternatives to ITIL are feasible options for HEIs in South Africa; and to validate the proposed strategy by verifying its quality, utility and efficacy. A comprehensive literature review provides information on various ITSM standards, frameworks and methodologies. It also investigates ITSM adoption and implementation by organisations in general, and HEIs in particular, and how modern practices such as DevOps, Agile and Lean relate to ITSM. Thereafter, an online survey is used to determine the status of ITSM maturity levels at South African HEIs, and whether alternatives to ITIL are being used. Expert interviews are used to obtain additional information on what is required to formulate the proposed strategy. The findings from the literature review, survey and expert interviews are used to develop a four-step strategy, which was evaluated for its quality, utility and efficacy through an online assessment by the same experts. This strategy can be considered a useful tool for Higher Education Institutions in South Africa if they wish to increase their levels of IT Service Management maturity. The findings of this study make a substantial contribution to the field of ITSM research at South African Higher Education Institutions.
- Full Text:
- Date Issued: 2019
The medicinal chemistry of selected halogenated diketopiperazines CYCLO(CIS-PRO-4F-PRO) and CYCLO(L-PHE-4I-VAL)
- Authors: Dakada, Vuyokazi
- Date: 2019
- Subjects: Medicinal plants , Drug development Cells -- Effect of drugs on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39370 , vital:35221
- Description: Generally, peptides are selective and efficacious compounds; as a result, they are the best candidates for drug discovery and development. Most peptide-based drugs have been approved for clinical use. The 2,5-Diketopiperazines (DKPs), also known as cyclic dipeptides, are simple compounds which come from nature. Many DKPs are extracted from animals and plants. For example, cyclo(Proline(Pro)-Leucine(Leu)), cyclo(Proline-Valine(Val)), cyclo(Proline-Phenylalanine(Phe)) etc. In this study cyclo(cis-Proline(Pro)-4F-Proline(Pro)) and cyclo(L- Phenylalanine(Phe)-4I- Valine (Val)) were synthesized from their linear esters using a method modified by Milne et al. (1992). This method yielded good results. However, cyclo(L-Phe-4I-Val) degraded due to physicochemical stability attributes caused by hygroscopicity and photosensitivity. Quantitative analysis and evaluation of physicochemical properties of each dipeptide was achieved by using scanning electron microscopy, thermal analysis (differential scanning calorimetry and thermogravimetric analysis) and X-ray powder diffraction. To determine the purity of the cyclic dipeptide, high performance liquid chromatography and thin layer chromatography was used. The structural elucidation of the cyclic dipeptides was carried by employing infrared spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy and, molecular modelling and computational chemistry. The aim of this research was to discover possible biological activity of cyclo(cis-Pro-4-F-Pro) and cyclo(L-Phe-4I-Val) with respect to their antimicrobial, anticancer, anti-diabetic and haematological effects. Cyclo(cis-Pro-4Fluoro-Pro) had no inhibitory effect on the antimicrobial strains tested, and cyclo(L-Phe-4Iodo-Val) could not be tested as the compound decomposed.
- Full Text:
- Date Issued: 2019
- Authors: Dakada, Vuyokazi
- Date: 2019
- Subjects: Medicinal plants , Drug development Cells -- Effect of drugs on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39370 , vital:35221
- Description: Generally, peptides are selective and efficacious compounds; as a result, they are the best candidates for drug discovery and development. Most peptide-based drugs have been approved for clinical use. The 2,5-Diketopiperazines (DKPs), also known as cyclic dipeptides, are simple compounds which come from nature. Many DKPs are extracted from animals and plants. For example, cyclo(Proline(Pro)-Leucine(Leu)), cyclo(Proline-Valine(Val)), cyclo(Proline-Phenylalanine(Phe)) etc. In this study cyclo(cis-Proline(Pro)-4F-Proline(Pro)) and cyclo(L- Phenylalanine(Phe)-4I- Valine (Val)) were synthesized from their linear esters using a method modified by Milne et al. (1992). This method yielded good results. However, cyclo(L-Phe-4I-Val) degraded due to physicochemical stability attributes caused by hygroscopicity and photosensitivity. Quantitative analysis and evaluation of physicochemical properties of each dipeptide was achieved by using scanning electron microscopy, thermal analysis (differential scanning calorimetry and thermogravimetric analysis) and X-ray powder diffraction. To determine the purity of the cyclic dipeptide, high performance liquid chromatography and thin layer chromatography was used. The structural elucidation of the cyclic dipeptides was carried by employing infrared spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy and, molecular modelling and computational chemistry. The aim of this research was to discover possible biological activity of cyclo(cis-Pro-4-F-Pro) and cyclo(L-Phe-4I-Val) with respect to their antimicrobial, anticancer, anti-diabetic and haematological effects. Cyclo(cis-Pro-4Fluoro-Pro) had no inhibitory effect on the antimicrobial strains tested, and cyclo(L-Phe-4Iodo-Val) could not be tested as the compound decomposed.
- Full Text:
- Date Issued: 2019
The Kinshasa-based Kin ArtStudio in the Democratic Republic of Congo: visual arts spaces and the potential to challenge global art's representative and legitimizing mechanisms
- Tshilumba Mukendi, Jean-Sylvain
- Authors: Tshilumba Mukendi, Jean-Sylvain
- Date: 2019
- Subjects: Space (Art) , Art -- Congo (Democratic Republic) , Art and globalization , Postcolonialism and the arts -- Congo (Democratic Republic) , Arts, Modern -- 21st century , Arts publicity , Arts, Modern -- 21st century -- Economic aspects , Arts, Modern -- 21st century -- Social aspects , Bondo, Vitshois Mwilambwe , Kin ArtStudio , Beauté Congo – 1926-2015 – Congo Kitoko
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115050 , vital:34073
- Description: The emergence of visual art spaces over the past few decades on the African continent invites art practitioners, historians and critics to re-examine the conditions of production, diffusion and reception of contemporary art of Africa. In this thesis I critically engage with these conditions in relation to artworks and practices of the Democratic Republic of Congo, considering the curatorial logic that has governed the ‘global art world’. I focus on the Kin ArtStudio as my main case study. I undertook research within this art space in 2016, from the 10th of April to the 15th of June, and again from the 16th of July to the 12th of September. My position as a participant observer turned out to be as engaging as informative. The Kin ArtStudio is a Kinshasa-based visual art platform founded in 2011 by the Congolese artist Vitshois Mwilambwe Bondo. It was established out of the will to empower emerging artists in that specific context, and facilitate the negotiation that the legitimization of their creations entails in today’s global art and cultural dynamics. In order to evaluate the stakes of such negotiation, I start with reviewing the existing mechanisms, trends and networks that have legitimized visual art productions of the Democratic Republic of Congo on a global stage, as exemplified by the Beauté Congo – Congo Kitoko exhibition (2015). Then, my enquiry evolves towards specificity, towards the immediacy and the subjectivity that characterize Kinshasa's urban and socio-cultural context, and visual art practices therein. Subjectivity also applies to my four months immersive experience with that art space. Drawing from my observations, setbacks, hopes and recent academic and practical debates around contemporary art practices on the African continent, the role those art spaces can play in the curatorship, circulation, reception and commodification of contemporary art productions cannot be underestimated. While operating in lasting postcolonial settings, they are going through the negotiation of their global and translocal situatedness, which can in turn lead to new legitimizing narratives. These will more appropriately inform understandings of contemporary art practices of Africa, challenging the identifying prism sustained by the ‘global art world’.
- Full Text:
- Date Issued: 2019
- Authors: Tshilumba Mukendi, Jean-Sylvain
- Date: 2019
- Subjects: Space (Art) , Art -- Congo (Democratic Republic) , Art and globalization , Postcolonialism and the arts -- Congo (Democratic Republic) , Arts, Modern -- 21st century , Arts publicity , Arts, Modern -- 21st century -- Economic aspects , Arts, Modern -- 21st century -- Social aspects , Bondo, Vitshois Mwilambwe , Kin ArtStudio , Beauté Congo – 1926-2015 – Congo Kitoko
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115050 , vital:34073
- Description: The emergence of visual art spaces over the past few decades on the African continent invites art practitioners, historians and critics to re-examine the conditions of production, diffusion and reception of contemporary art of Africa. In this thesis I critically engage with these conditions in relation to artworks and practices of the Democratic Republic of Congo, considering the curatorial logic that has governed the ‘global art world’. I focus on the Kin ArtStudio as my main case study. I undertook research within this art space in 2016, from the 10th of April to the 15th of June, and again from the 16th of July to the 12th of September. My position as a participant observer turned out to be as engaging as informative. The Kin ArtStudio is a Kinshasa-based visual art platform founded in 2011 by the Congolese artist Vitshois Mwilambwe Bondo. It was established out of the will to empower emerging artists in that specific context, and facilitate the negotiation that the legitimization of their creations entails in today’s global art and cultural dynamics. In order to evaluate the stakes of such negotiation, I start with reviewing the existing mechanisms, trends and networks that have legitimized visual art productions of the Democratic Republic of Congo on a global stage, as exemplified by the Beauté Congo – Congo Kitoko exhibition (2015). Then, my enquiry evolves towards specificity, towards the immediacy and the subjectivity that characterize Kinshasa's urban and socio-cultural context, and visual art practices therein. Subjectivity also applies to my four months immersive experience with that art space. Drawing from my observations, setbacks, hopes and recent academic and practical debates around contemporary art practices on the African continent, the role those art spaces can play in the curatorship, circulation, reception and commodification of contemporary art productions cannot be underestimated. While operating in lasting postcolonial settings, they are going through the negotiation of their global and translocal situatedness, which can in turn lead to new legitimizing narratives. These will more appropriately inform understandings of contemporary art practices of Africa, challenging the identifying prism sustained by the ‘global art world’.
- Full Text:
- Date Issued: 2019
Nonlinear optical behavior of n-tuple decker phthalocyanines at the nanosecond regime
- Sekhosana, Kutloana E, Nyokong, Tebello
- Authors: Sekhosana, Kutloana E , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234603 , vital:50212 , xlink:href="https://doi.org/10.1039/C9RA01836K"
- Description: The coordination system of rare-earth n-tuple decker phthalocyanines would be better suited with appropriate metal ions with the correct coordination number and the solvent system of the reaction, amongst other reasons, for the formation of n-tuple decker phthalocyanines. As a result, these complexes are very rare. In this manuscript, we present new n-tuple decker phthalocyanines in the form of double- (complex 2), quadruple- (complex 3a) and sextuple-decker phthalocyanines (complex 3b), all of which contain neodymium and cadmium metal ions. The primary focus is the investigation of the nonlinear optical (NLO) mechanisms responsible for the observed reverse saturable absorption. While the extension of the π-electron system has been found to enhance the nonlinear optical behavior of complexes 3a and 3b, a change in the NLO mechanisms has been observed, with complex 2 lacking the triplet state population, as revealed by a laser flash photolysis technique. It has also been established that the excited state absorption cross sections follow a clear order of magnitude for the complexes under investigation: σ23 (for 3b) > σ23 (for 3a) > σ1m (for 2). This trend evidences the effects of the extension of the π-electron system.
- Full Text:
- Date Issued: 2019
- Authors: Sekhosana, Kutloana E , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234603 , vital:50212 , xlink:href="https://doi.org/10.1039/C9RA01836K"
- Description: The coordination system of rare-earth n-tuple decker phthalocyanines would be better suited with appropriate metal ions with the correct coordination number and the solvent system of the reaction, amongst other reasons, for the formation of n-tuple decker phthalocyanines. As a result, these complexes are very rare. In this manuscript, we present new n-tuple decker phthalocyanines in the form of double- (complex 2), quadruple- (complex 3a) and sextuple-decker phthalocyanines (complex 3b), all of which contain neodymium and cadmium metal ions. The primary focus is the investigation of the nonlinear optical (NLO) mechanisms responsible for the observed reverse saturable absorption. While the extension of the π-electron system has been found to enhance the nonlinear optical behavior of complexes 3a and 3b, a change in the NLO mechanisms has been observed, with complex 2 lacking the triplet state population, as revealed by a laser flash photolysis technique. It has also been established that the excited state absorption cross sections follow a clear order of magnitude for the complexes under investigation: σ23 (for 3b) > σ23 (for 3a) > σ1m (for 2). This trend evidences the effects of the extension of the π-electron system.
- Full Text:
- Date Issued: 2019
Effect of substituents on the photophysical properties and nonlinear optical properties of asymmetrical zinc(II) phthalocyanine when conjugated to semiconductor quantum dots
- Authors: Mgidlana, Sithi
- Date: 2019
- Subjects: Nonlinear optics , Quantum dots , Phthalocyanines , Zinc
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97152 , vital:31404
- Description: Various characterization techniques have been used to characterize the synthesized asymmetrical zinc phthalocyanines (ZnPc) derivatives. Techniques include Ultraviolet-visible (UV-vis) spectrophotometry, matrix assisted laser desorption time of flight mass spectrometry (MALD-TOF MS), proton nuclear magnetic resonance (1H-NMR), elemental analysis and Fourier-transform infra-red spectroscopy (FT-IR). The complexes are covalently linked to core/shell and core/shell/shell semiconductor quantum dots (SQDs) via amide bond formation. Photophysical properties of complexes improved in the presence of semiconductor quantum dots (SQDs). SQDs contain cadmium/telluride (CdTe) as core, coated in the first shell with zinc selenide (ZnSe) or zinc sulfide (ZnS) and with zinc oxide (ZnO) in second shell. The photophysical properties of the phthalocyanine (Pc) complexes and their conjugates with SQDs are investigated in solution. Triplet quantum yields of complexes improved in the presence of semiconductor quantum dots. The optical limiting behaviour of the Pc complexes and conjugates are assessed using the open aperture Z–scan technique at laser excitation wavelength of 532 nm with 10 ns pulse. Pcs complexes showed good nonlinear optical response with higher nonlinear absorption coefficient. The conjugates afforded higher nonlinear absorption coefficient than Pc complexes alone.
- Full Text:
- Date Issued: 2019
- Authors: Mgidlana, Sithi
- Date: 2019
- Subjects: Nonlinear optics , Quantum dots , Phthalocyanines , Zinc
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97152 , vital:31404
- Description: Various characterization techniques have been used to characterize the synthesized asymmetrical zinc phthalocyanines (ZnPc) derivatives. Techniques include Ultraviolet-visible (UV-vis) spectrophotometry, matrix assisted laser desorption time of flight mass spectrometry (MALD-TOF MS), proton nuclear magnetic resonance (1H-NMR), elemental analysis and Fourier-transform infra-red spectroscopy (FT-IR). The complexes are covalently linked to core/shell and core/shell/shell semiconductor quantum dots (SQDs) via amide bond formation. Photophysical properties of complexes improved in the presence of semiconductor quantum dots (SQDs). SQDs contain cadmium/telluride (CdTe) as core, coated in the first shell with zinc selenide (ZnSe) or zinc sulfide (ZnS) and with zinc oxide (ZnO) in second shell. The photophysical properties of the phthalocyanine (Pc) complexes and their conjugates with SQDs are investigated in solution. Triplet quantum yields of complexes improved in the presence of semiconductor quantum dots. The optical limiting behaviour of the Pc complexes and conjugates are assessed using the open aperture Z–scan technique at laser excitation wavelength of 532 nm with 10 ns pulse. Pcs complexes showed good nonlinear optical response with higher nonlinear absorption coefficient. The conjugates afforded higher nonlinear absorption coefficient than Pc complexes alone.
- Full Text:
- Date Issued: 2019
The effectiveness of sandplay therapy with a Xhosa child
- Authors: Snelgar, Orrin Glenn
- Date: 2019
- Subjects: Sandplay -- Therapeutic use -- Case studies -- South Africa , Play therapy -- Case studies -- South Africa , Child psychotherapy -- Case studies -- South Africa , Children, Black -- Psychology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/179168 , vital:39876
- Description: This case study sought to determine whether Kalffian Sandtray Therapy was effective with a Xhosa child. In the context of ongoing discussions surrounding evidence-based practice and culturally appropriate interventions, no published research has yet explored the effectiveness of this classical tool within this significant South African demographic. In an effort to address this omission, the research adopted a mixed methods approach where Kalffian analysis of the sandplay process was evaluated in conjunction with quantitative measures (the Strengths and Difficulties Questionnaire and the Young Person’s Clinical Outcomes in Routine Evaluation). The results of this triangulation revealed a complex picture of improved interpersonal functioning and stagnant (or worsened) emotional wellbeing after five sessions. Contextualised interpretations of these findings are discussed and recommendations made for future sandplay practice and research in the South African context.
- Full Text:
- Date Issued: 2019
- Authors: Snelgar, Orrin Glenn
- Date: 2019
- Subjects: Sandplay -- Therapeutic use -- Case studies -- South Africa , Play therapy -- Case studies -- South Africa , Child psychotherapy -- Case studies -- South Africa , Children, Black -- Psychology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/179168 , vital:39876
- Description: This case study sought to determine whether Kalffian Sandtray Therapy was effective with a Xhosa child. In the context of ongoing discussions surrounding evidence-based practice and culturally appropriate interventions, no published research has yet explored the effectiveness of this classical tool within this significant South African demographic. In an effort to address this omission, the research adopted a mixed methods approach where Kalffian analysis of the sandplay process was evaluated in conjunction with quantitative measures (the Strengths and Difficulties Questionnaire and the Young Person’s Clinical Outcomes in Routine Evaluation). The results of this triangulation revealed a complex picture of improved interpersonal functioning and stagnant (or worsened) emotional wellbeing after five sessions. Contextualised interpretations of these findings are discussed and recommendations made for future sandplay practice and research in the South African context.
- Full Text:
- Date Issued: 2019
The Afropolitan flâneur: literary representations of the city and contemporary urban identities in selected African and transnational texts
- Authors: Leff, Carol Willa
- Date: 2019
- Subjects: City and town life in literature , African literature (English) -- History and criticism , Flaneurs in literature
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115082 , vital:34076
- Description: When an individual walks the urban landscape there is a unique symbiosis between self and city. It is through walking the cityscape and observing the crowd and the surrounding environment that the archetypal literary figure of the European flâneur acts as a mirror of a particular time and space. But how might such a flâneur walk and observe the city in contemporary African and transnational literary texts? I argue that there is a literary re-imagining and repurposing of the flâneur figure which has hitherto not been acknowledged and explored: an Afropolitan flâneur. ‘Afropolitan’ is a term popularised by Taiye Selasi in a 2005 essay to refer to a ‘scattered tribe’ of ‘Africans of the world’ (n. pag.). In this dissertation, the entanglement of the Afropolitan subject and the European flâneur brings together past and present, Africa and the West. I first provide a historical and theoretical framework to illustrate how the flâneur figure ‘migrated’ from Europe to Africa, and how this figure is to be understood as a literary construct, in relation to current considerations of Afropolitanism. I go on to discuss a wide range of texts that engage with Afropolitan flâneurs who traverse cities in Africa (such as Johannesburg, Cape Town and Lagos), or global north cities (New York, Paris and London). While some of the Afropolitan flâneurs depicted in these texts are migrants or homeless individuals who struggle to adapt easily to a new environment, others, despite being more privileged, also sometimes experience uncomfortable assimilation in their new or strange city space. There are also those who seem to feel equally at home wherever they find themselves. As these Afropolitan flâneurs walk their way through the urban landscape in the texts under examination, they reflect different ways of being in the city. By problematising the binaries of local/global, national/transnational, black/white, slum/paradise, this dissertation seeks to address issues of belonging or not belonging and gestures towards new ways of understanding what it means to be an African in the world.
- Full Text:
- Date Issued: 2019
- Authors: Leff, Carol Willa
- Date: 2019
- Subjects: City and town life in literature , African literature (English) -- History and criticism , Flaneurs in literature
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115082 , vital:34076
- Description: When an individual walks the urban landscape there is a unique symbiosis between self and city. It is through walking the cityscape and observing the crowd and the surrounding environment that the archetypal literary figure of the European flâneur acts as a mirror of a particular time and space. But how might such a flâneur walk and observe the city in contemporary African and transnational literary texts? I argue that there is a literary re-imagining and repurposing of the flâneur figure which has hitherto not been acknowledged and explored: an Afropolitan flâneur. ‘Afropolitan’ is a term popularised by Taiye Selasi in a 2005 essay to refer to a ‘scattered tribe’ of ‘Africans of the world’ (n. pag.). In this dissertation, the entanglement of the Afropolitan subject and the European flâneur brings together past and present, Africa and the West. I first provide a historical and theoretical framework to illustrate how the flâneur figure ‘migrated’ from Europe to Africa, and how this figure is to be understood as a literary construct, in relation to current considerations of Afropolitanism. I go on to discuss a wide range of texts that engage with Afropolitan flâneurs who traverse cities in Africa (such as Johannesburg, Cape Town and Lagos), or global north cities (New York, Paris and London). While some of the Afropolitan flâneurs depicted in these texts are migrants or homeless individuals who struggle to adapt easily to a new environment, others, despite being more privileged, also sometimes experience uncomfortable assimilation in their new or strange city space. There are also those who seem to feel equally at home wherever they find themselves. As these Afropolitan flâneurs walk their way through the urban landscape in the texts under examination, they reflect different ways of being in the city. By problematising the binaries of local/global, national/transnational, black/white, slum/paradise, this dissertation seeks to address issues of belonging or not belonging and gestures towards new ways of understanding what it means to be an African in the world.
- Full Text:
- Date Issued: 2019
Statistical Analysis of the Radio-Interferometric Measurement Equation, a derived adaptive weighting scheme, and applications to LOFAR-VLBI observation of the Extended Groth Strip
- Authors: Bonnassieux, Etienne
- Date: 2019
- Subjects: Radio astronomy , Astrophysics , Astrophysics -- Instruments -- Calibration , Imaging systems in astronomy , Radio interferometers , Radio telescopes , Astronomy -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/93789 , vital:30942
- Description: J.R.R Tolkien wrote, in his Mythopoeia, that “He sees no stars who does not see them first, of living silver made that sudden burst, to flame like flowers beneath the ancient song”. In his defense of myth-making, he formulates the argument that the attribution of meaning is an act of creation - that “trees are not ‘trees’ until so named and seen” - and that this capacity for creation defines the human creature. The scientific endeavour, in this context, can be understood as a social expression of a fundamental feature of humanity, and from this endeavour flows much understanding. This thesis, one thread among many, focuses on the study of astronomical objects as seen by the radio waves they emit. What are radio waves? Electromagnetic waves were theorised by James Clerk Maxwell (Maxwell 1864) in his great theoretical contribution to modern physics, their speed matching the speed of light as measured by Ole Christensen R0mer and, later, James Bradley. It was not until Heinrich Rudolf Hertz’s 1887 experiment that these waves were measured in a laboratory, leading to the dawn of radio communications - and, later, radio astronomy. The link between radio waves and light was one of association: light is known to behave as a wave (Young double-slit experiment), with the same propagation speed as electromagnetic radiation. Light “proper” is also known to exist beyond the optical regime: Herschel’s experiment shows that when diffracted through a prism, sunlight warms even those parts of a desk which are not observed to be lit (first evidence of infrared light). The link between optical light and unseen electromagnetic radiation is then an easy step to make, and one confirmed through countless technological applications (e.g. optical fiber to name but one). And as soon as this link is established, a question immediately comes to the mind of the astronomer: what does the sky, our Universe, look like to the radio “eye”? Radio astronomy has a short but storied history: from Karl Jansky’s serendipitous observation of the centre of the Milky Way, which outshines our Sun in the radio regime, in 1933, to Grote Reber’s hand-built back-yard radio antenna in 1937, which successfully detected radio emission from the Milky Way itself, to such monumental projects as the Square Kilometer Array and its multiple pathfinders, it has led to countless discoveries and the opening of a truly new window on the Universe. The work presented in this thesis is a contribution to this discipline - the culmination of three years of study, which is a rather short time to get a firm grasp of radio interferometry both in theory and in practice. The need for robust, automated methods - which are improving daily, thanks to the tireless labour of the scientists in the field - is becoming ever stronger as the SKA approaches, looming large on the horizon; but even today, in the precursor era of LOFAR, MeerKAT and other pathfinders, it is keenly felt. When I started my doctorate, the sheer scale of the task at hand felt overwhelming - to actually be able to contribute to its resolution seemed daunting indeed! Thankfully, as the saying goes, no society sets for itself material goals which it cannot achieve. This thesis took place at an exciting time for radio interferometry: at the start of my doctorate, the LOFAR international stations were - to my knowledge - only beginning to be used, and even then, only tentatively; MeerKAT had not yet shown its first light; the techniques used throughout my work were still being developed. At the time of writing, great strides have been made. One of the greatest technical challenges of LOFAR - imaging using the international stations - is starting to become reality. This technical challenge is the key problem that this thesis set out to address. While we only achieved partial success so far, it is a testament to the difficulty of the task that it is not yet truly resolved. One of the major results of this thesis is a model of a bright resolved source near a famous extragalactic field: properly modeling this source not only allows the use of international LOFAR stations, but also grants deeper access to the extragalactic field itself, which is otherwise polluted by the 3C source’s sidelobes. This result was only achieved thanks to the other major result of this thesis: the development of a theoretical framework with which to better understand the effect of calibration errors on images made from interferometric data, and an algorithm to strongly mitigate them. The structure of this manuscript is as follows: we begin with an introduction to radio interferometry, LOFAR, and the emission mechanisms which dominate for our field of interest. These introductions are primarily intended to give a brief overview of the technical aspects of the data reduced in this thesis. We follow with an overview of the Measurement Equation formalism, which underpins our theoretical work. This is the keystone of this thesis. We then show the theoretical work that was developed as part of the research work done during the doctorate - which was published in Astronomy & Astrophysics. Its practical application - a quality-based weighting scheme - is used throughout our data reduction. This data reduction is the next topic of this thesis: we contextualise the scientific interest of the data we reduce, and explain both the methods and the results we achieve.
- Full Text:
- Date Issued: 2019
- Authors: Bonnassieux, Etienne
- Date: 2019
- Subjects: Radio astronomy , Astrophysics , Astrophysics -- Instruments -- Calibration , Imaging systems in astronomy , Radio interferometers , Radio telescopes , Astronomy -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/93789 , vital:30942
- Description: J.R.R Tolkien wrote, in his Mythopoeia, that “He sees no stars who does not see them first, of living silver made that sudden burst, to flame like flowers beneath the ancient song”. In his defense of myth-making, he formulates the argument that the attribution of meaning is an act of creation - that “trees are not ‘trees’ until so named and seen” - and that this capacity for creation defines the human creature. The scientific endeavour, in this context, can be understood as a social expression of a fundamental feature of humanity, and from this endeavour flows much understanding. This thesis, one thread among many, focuses on the study of astronomical objects as seen by the radio waves they emit. What are radio waves? Electromagnetic waves were theorised by James Clerk Maxwell (Maxwell 1864) in his great theoretical contribution to modern physics, their speed matching the speed of light as measured by Ole Christensen R0mer and, later, James Bradley. It was not until Heinrich Rudolf Hertz’s 1887 experiment that these waves were measured in a laboratory, leading to the dawn of radio communications - and, later, radio astronomy. The link between radio waves and light was one of association: light is known to behave as a wave (Young double-slit experiment), with the same propagation speed as electromagnetic radiation. Light “proper” is also known to exist beyond the optical regime: Herschel’s experiment shows that when diffracted through a prism, sunlight warms even those parts of a desk which are not observed to be lit (first evidence of infrared light). The link between optical light and unseen electromagnetic radiation is then an easy step to make, and one confirmed through countless technological applications (e.g. optical fiber to name but one). And as soon as this link is established, a question immediately comes to the mind of the astronomer: what does the sky, our Universe, look like to the radio “eye”? Radio astronomy has a short but storied history: from Karl Jansky’s serendipitous observation of the centre of the Milky Way, which outshines our Sun in the radio regime, in 1933, to Grote Reber’s hand-built back-yard radio antenna in 1937, which successfully detected radio emission from the Milky Way itself, to such monumental projects as the Square Kilometer Array and its multiple pathfinders, it has led to countless discoveries and the opening of a truly new window on the Universe. The work presented in this thesis is a contribution to this discipline - the culmination of three years of study, which is a rather short time to get a firm grasp of radio interferometry both in theory and in practice. The need for robust, automated methods - which are improving daily, thanks to the tireless labour of the scientists in the field - is becoming ever stronger as the SKA approaches, looming large on the horizon; but even today, in the precursor era of LOFAR, MeerKAT and other pathfinders, it is keenly felt. When I started my doctorate, the sheer scale of the task at hand felt overwhelming - to actually be able to contribute to its resolution seemed daunting indeed! Thankfully, as the saying goes, no society sets for itself material goals which it cannot achieve. This thesis took place at an exciting time for radio interferometry: at the start of my doctorate, the LOFAR international stations were - to my knowledge - only beginning to be used, and even then, only tentatively; MeerKAT had not yet shown its first light; the techniques used throughout my work were still being developed. At the time of writing, great strides have been made. One of the greatest technical challenges of LOFAR - imaging using the international stations - is starting to become reality. This technical challenge is the key problem that this thesis set out to address. While we only achieved partial success so far, it is a testament to the difficulty of the task that it is not yet truly resolved. One of the major results of this thesis is a model of a bright resolved source near a famous extragalactic field: properly modeling this source not only allows the use of international LOFAR stations, but also grants deeper access to the extragalactic field itself, which is otherwise polluted by the 3C source’s sidelobes. This result was only achieved thanks to the other major result of this thesis: the development of a theoretical framework with which to better understand the effect of calibration errors on images made from interferometric data, and an algorithm to strongly mitigate them. The structure of this manuscript is as follows: we begin with an introduction to radio interferometry, LOFAR, and the emission mechanisms which dominate for our field of interest. These introductions are primarily intended to give a brief overview of the technical aspects of the data reduced in this thesis. We follow with an overview of the Measurement Equation formalism, which underpins our theoretical work. This is the keystone of this thesis. We then show the theoretical work that was developed as part of the research work done during the doctorate - which was published in Astronomy & Astrophysics. Its practical application - a quality-based weighting scheme - is used throughout our data reduction. This data reduction is the next topic of this thesis: we contextualise the scientific interest of the data we reduce, and explain both the methods and the results we achieve.
- Full Text:
- Date Issued: 2019
The development of palladium nanoparticles for radiopharmaceutical application
- Authors: Gandidzanwa, Sendibitiyosi
- Date: 2019
- Subjects: Nanotechnology , Nanostructures Nanofluids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/42163 , vital:36631
- Description: The dissertation describes an in-depth synthesis and optimisation of palladium(0) nanoparticles of three distinct size ranges, respective capping agents, and cellular uptake studies using a non-toxic concentration (10 μM), laying a foundation for the design of palladium-based folate receptor-targeted theranostic nanoradiopharmaceutical. In the preliminary selection to determine the optimal diamines for the study, ethylenediamine, hexamethylenediamine, 1,10-diaminodecane, 1,12-diaminododecane, 1,4- diaminobenzene, 4,4’-ethylenedianiline, 1,2-diphenyl-1,2-diaminoethane, and tetraaminophthalocyanine were employed. The characterisation of the nanoparticles obtained from the in situ reduction of palladium(II) salt at room temperature by either 1,2,3- trihydroxybenze (pyrogallol), citric acid, sodium metabisulphite, sodium borohydride, hydrazine hydrate, or formaldehyde was performed. Ethylenediamine and sodium borohydride were found to be the best diamine capping and reducing agent, respectively. Systematic investigations determined that the nanoparticle synthesis was dependent on various reaction parameters: such as reaction temperature, time, reductant reducing power, and capping agents. The parameters effects on the nanoparticle size, morphology, shape, stability, crystallinity, and surface charge were investigated. The optical properties, elemental composition, functional group, concentration and molecular weight for the synthesised nanoparticles or conjugates were determined. These properties were analysed using Ultraviolet–visible spectroscopy (UV-Vis), high resolution transmission electron microscopy (HRTEM) coupled with selective area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), zeta potential (ZP), dynamic light scattering (DLS), elemental analysis (EA), 1H and 13C-nuclear magnetic resonance (1H- and 13CNMR), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and liquid chromatography-mass spectroscopy (LC-MS). The in vitro cytotoxicity, cell uptake, and internalisation studies of palladium nanoparticles (10 μM) ranging in size and different types of capping agent were performed using three breast cancer cell lines: MDA-MB-468 , MCF-7 and MDA-MB-231 , and a non-tumorigenic MCF-10A breast cell line. The cell uptake and internalisation were investigated using ICP-OES and TEM. A high dependence between reduction rate and concentration of palladium precursor was observed for the room temperature synthesis of palladium nanoparticles, and the employed synthesis procedure will be applied to the hot palladium isotope (109Pd). A facile, green, aqueous synthesis route for palladium nanoparticles at room temperature was developed, and the synthesised nanoparticles indicated narrow size distributions. A concentration dependence between cytotoxicity and palladium nanoparticles was observed, with lower concentrations (10 μM) exhibiting minimal cytotoxicity relative to higher concentrations (100 μM). The cellular uptake of palladium nanoparticles was found to be concentration, folate-receptor, capping agent, and cell line proliferation-dependent. Well-defined, monodispersed, and negatively charged folate-ethylenediamine and folate-phthalocyanine capped palladium nanoparticles were taken up by cells, with higher nanoparticle internalisation in folate receptor positive tumorigenic cells relative to folate receptor negative non-tumorigenic cells. It can be concluded that palladium(0) nanoparticles can be synthesised from the reduction of palladium(II) by sodium borohydride at room temperature. The folate-conjugated palladium nanoparticles are non-cytotoxic at 10 μM and were successfully optimised and selectively delivered to folate receptor-positive breast cancer cells (MDA-MB-231 and MCF-7) relative to non-tumorigenic breast cells (MCF-10A) and folate receptor negative cancer cells (MDA-MB-468).
- Full Text:
- Date Issued: 2019
- Authors: Gandidzanwa, Sendibitiyosi
- Date: 2019
- Subjects: Nanotechnology , Nanostructures Nanofluids
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/42163 , vital:36631
- Description: The dissertation describes an in-depth synthesis and optimisation of palladium(0) nanoparticles of three distinct size ranges, respective capping agents, and cellular uptake studies using a non-toxic concentration (10 μM), laying a foundation for the design of palladium-based folate receptor-targeted theranostic nanoradiopharmaceutical. In the preliminary selection to determine the optimal diamines for the study, ethylenediamine, hexamethylenediamine, 1,10-diaminodecane, 1,12-diaminododecane, 1,4- diaminobenzene, 4,4’-ethylenedianiline, 1,2-diphenyl-1,2-diaminoethane, and tetraaminophthalocyanine were employed. The characterisation of the nanoparticles obtained from the in situ reduction of palladium(II) salt at room temperature by either 1,2,3- trihydroxybenze (pyrogallol), citric acid, sodium metabisulphite, sodium borohydride, hydrazine hydrate, or formaldehyde was performed. Ethylenediamine and sodium borohydride were found to be the best diamine capping and reducing agent, respectively. Systematic investigations determined that the nanoparticle synthesis was dependent on various reaction parameters: such as reaction temperature, time, reductant reducing power, and capping agents. The parameters effects on the nanoparticle size, morphology, shape, stability, crystallinity, and surface charge were investigated. The optical properties, elemental composition, functional group, concentration and molecular weight for the synthesised nanoparticles or conjugates were determined. These properties were analysed using Ultraviolet–visible spectroscopy (UV-Vis), high resolution transmission electron microscopy (HRTEM) coupled with selective area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), zeta potential (ZP), dynamic light scattering (DLS), elemental analysis (EA), 1H and 13C-nuclear magnetic resonance (1H- and 13CNMR), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and liquid chromatography-mass spectroscopy (LC-MS). The in vitro cytotoxicity, cell uptake, and internalisation studies of palladium nanoparticles (10 μM) ranging in size and different types of capping agent were performed using three breast cancer cell lines: MDA-MB-468 , MCF-7 and MDA-MB-231 , and a non-tumorigenic MCF-10A breast cell line. The cell uptake and internalisation were investigated using ICP-OES and TEM. A high dependence between reduction rate and concentration of palladium precursor was observed for the room temperature synthesis of palladium nanoparticles, and the employed synthesis procedure will be applied to the hot palladium isotope (109Pd). A facile, green, aqueous synthesis route for palladium nanoparticles at room temperature was developed, and the synthesised nanoparticles indicated narrow size distributions. A concentration dependence between cytotoxicity and palladium nanoparticles was observed, with lower concentrations (10 μM) exhibiting minimal cytotoxicity relative to higher concentrations (100 μM). The cellular uptake of palladium nanoparticles was found to be concentration, folate-receptor, capping agent, and cell line proliferation-dependent. Well-defined, monodispersed, and negatively charged folate-ethylenediamine and folate-phthalocyanine capped palladium nanoparticles were taken up by cells, with higher nanoparticle internalisation in folate receptor positive tumorigenic cells relative to folate receptor negative non-tumorigenic cells. It can be concluded that palladium(0) nanoparticles can be synthesised from the reduction of palladium(II) by sodium borohydride at room temperature. The folate-conjugated palladium nanoparticles are non-cytotoxic at 10 μM and were successfully optimised and selectively delivered to folate receptor-positive breast cancer cells (MDA-MB-231 and MCF-7) relative to non-tumorigenic breast cells (MCF-10A) and folate receptor negative cancer cells (MDA-MB-468).
- Full Text:
- Date Issued: 2019