Effects of symmetry and the number of positive charges on the photocatalytic activity of indium phthalocyanines when embedded in electrospun fibers
- Chakona, Gamuchirai, Nyokong, Tebello
- Authors: Chakona, Gamuchirai , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188304 , vital:44743 , xlink:href="https://doi.org/10.1016/j.ica.2016.12.025"
- Description: Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric indium(III) phthalocyanines photosensitizers: the first consisting of one quaternized 4-pyridyloxyl and no other substituents (complex 1) and the second containing three quaternized 4-pyridylsulfanyl units and one aminophenoxy (complex 3). The asymmetry of complex 3 is additionally caused by the presence of two linking atoms (O and S). The symmetrically substituted indium(III) phthalocyanine containing four quaternized 4-pyridyloxyl units (complex 2) was also studied. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalytic transformation of 4-chlorophenol and bisphenol A. When immobilized on electrospun fibers, complexes 1, 2 and 3 gave singlet oxygen values of 0.31, 0.39 and 0.50 in water, respectively. Complex 3 showed the best photocatalytic behavior with observed rate constants of 2.8 × 10−3 min−1 for bisphenol A and 3.8 × 10−3 min−1 for 4-chlorophenol.
- Full Text:
- Authors: Chakona, Gamuchirai , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188304 , vital:44743 , xlink:href="https://doi.org/10.1016/j.ica.2016.12.025"
- Description: Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric indium(III) phthalocyanines photosensitizers: the first consisting of one quaternized 4-pyridyloxyl and no other substituents (complex 1) and the second containing three quaternized 4-pyridylsulfanyl units and one aminophenoxy (complex 3). The asymmetry of complex 3 is additionally caused by the presence of two linking atoms (O and S). The symmetrically substituted indium(III) phthalocyanine containing four quaternized 4-pyridyloxyl units (complex 2) was also studied. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalytic transformation of 4-chlorophenol and bisphenol A. When immobilized on electrospun fibers, complexes 1, 2 and 3 gave singlet oxygen values of 0.31, 0.39 and 0.50 in water, respectively. Complex 3 showed the best photocatalytic behavior with observed rate constants of 2.8 × 10−3 min−1 for bisphenol A and 3.8 × 10−3 min−1 for 4-chlorophenol.
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Local setting influences the quantity of household food waste in mid-sized South African towns
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60866 , vital:27847 , https://doi.org/10.1371/journal.pone.0189407
- Description: The world faces a food security challenge with approximately 868 million people undernourished and about two billion people suffering from the negative health consequences of micronutrient deficiencies. Yet, it is believed that at least 33% of food produced for human consumption is lost or wasted along the food chain. As food waste has a negative effect on food security, the present study sought to quantify household food waste along the ruralurban continuum in three South African mid-sized towns situated along an agro-ecological gradient. We quantified the types of foods and drinks that households threw away in the previous 48 hours and identified the causes of household food waste in the three sites. More households wasted prepared food (27%) than unprepared food (15%) and drinks (8%). However, households threw away greater quantities of unprepared food in the 48-hour recall period (268.6±610.1 g, 90% confidence interval: 175.5 to 361.7 g) compared to prepared food (121.0±132.4 g, 90% confidence interval: 100.8 to 141.3 g) and drinks (77.0±192.5 ml, 90% confidence interval: 47.7 to 106.4 ml). The estimated per capita food waste (5±10 kg of unprepared food waste, 3±4 kg of prepared food waste and 1±3 litres of drinks waste per person per year) overlaps with that estimated for other developing countries, but lower than most developed countries. However, the estimated average amount of food waste per person per year for this study (12.35 kg) was higher relative to that estimated for developing countries (8.5 kg per person per year). Household food waste was mainly a result of consumer behavior concerning food preparation and storage. Integrated approaches are required to address this developmental issue affecting South African societies, which include promoting sound food management to decrease household food waste. Also, increased awareness and educational campaigns for household food waste reduction interventions are discussed.
- Full Text:
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60866 , vital:27847 , https://doi.org/10.1371/journal.pone.0189407
- Description: The world faces a food security challenge with approximately 868 million people undernourished and about two billion people suffering from the negative health consequences of micronutrient deficiencies. Yet, it is believed that at least 33% of food produced for human consumption is lost or wasted along the food chain. As food waste has a negative effect on food security, the present study sought to quantify household food waste along the ruralurban continuum in three South African mid-sized towns situated along an agro-ecological gradient. We quantified the types of foods and drinks that households threw away in the previous 48 hours and identified the causes of household food waste in the three sites. More households wasted prepared food (27%) than unprepared food (15%) and drinks (8%). However, households threw away greater quantities of unprepared food in the 48-hour recall period (268.6±610.1 g, 90% confidence interval: 175.5 to 361.7 g) compared to prepared food (121.0±132.4 g, 90% confidence interval: 100.8 to 141.3 g) and drinks (77.0±192.5 ml, 90% confidence interval: 47.7 to 106.4 ml). The estimated per capita food waste (5±10 kg of unprepared food waste, 3±4 kg of prepared food waste and 1±3 litres of drinks waste per person per year) overlaps with that estimated for other developing countries, but lower than most developed countries. However, the estimated average amount of food waste per person per year for this study (12.35 kg) was higher relative to that estimated for developing countries (8.5 kg per person per year). Household food waste was mainly a result of consumer behavior concerning food preparation and storage. Integrated approaches are required to address this developmental issue affecting South African societies, which include promoting sound food management to decrease household food waste. Also, increased awareness and educational campaigns for household food waste reduction interventions are discussed.
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Minimum dietary diversity scores for women indicate micronutrient adequacy and food insecurity status in South African towns
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60930 , vital:27892 , http://dx.doi.org/10.3390/nu9080812
- Description: The lack of dietary diversity is a severe problem experienced by most poor households globally. In particular; women of reproductive age (WRA) are at high risk of inadequate intake of micronutrients resulting from diets dominated by starchy staples. The present study considered the diets, dietary diversity, and food security of women aged 15-49 years along the rural-urban continuum in three South African towns situated along an agro-ecological gradient. A 48 h dietary recall was conducted across two seasons with 554 women from rural, peri-urban, and urban locations of Richards Bay, Dundee, and Harrismith. Minimum Dietary Diversity for WRA (MDD-W) were calculated and a dichotomous indicator based on a set of ten food groups was used to determine if women had consumed at least five food groups the previous 48 h to achieve minimum dietary intake for women. The mean (±sd) MDD-W for Richards Bay (3.78 ± 0.07) was significantly higher than at Dundee (3.21 ± 0.08) and Harrismith (3.36 ± 0.07). Food security and MDD-W were significantly higher in urban locations than in peri-urban or rural ones. There was lower dependence on food purchasing in Richards Bay compared to Dundee and Harrismith. The majority of women in Richards Bay practiced subsistence agriculture, produced a surplus for sale, and collected wild foods which improved dietary intake and food security. The peri-urban populations had limited dietary intake and were more food insecure because of high levels of poverty, unemployment, and lack of land. Peri-urban dwellers are therefore more sensitive to changes in incomes and food prices because they lack safety nets to absorb income or price shocks as they purchase more, rather than growing their own food. This compromises dietary diversity as they have limited access to diverse foods.
- Full Text:
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60930 , vital:27892 , http://dx.doi.org/10.3390/nu9080812
- Description: The lack of dietary diversity is a severe problem experienced by most poor households globally. In particular; women of reproductive age (WRA) are at high risk of inadequate intake of micronutrients resulting from diets dominated by starchy staples. The present study considered the diets, dietary diversity, and food security of women aged 15-49 years along the rural-urban continuum in three South African towns situated along an agro-ecological gradient. A 48 h dietary recall was conducted across two seasons with 554 women from rural, peri-urban, and urban locations of Richards Bay, Dundee, and Harrismith. Minimum Dietary Diversity for WRA (MDD-W) were calculated and a dichotomous indicator based on a set of ten food groups was used to determine if women had consumed at least five food groups the previous 48 h to achieve minimum dietary intake for women. The mean (±sd) MDD-W for Richards Bay (3.78 ± 0.07) was significantly higher than at Dundee (3.21 ± 0.08) and Harrismith (3.36 ± 0.07). Food security and MDD-W were significantly higher in urban locations than in peri-urban or rural ones. There was lower dependence on food purchasing in Richards Bay compared to Dundee and Harrismith. The majority of women in Richards Bay practiced subsistence agriculture, produced a surplus for sale, and collected wild foods which improved dietary intake and food security. The peri-urban populations had limited dietary intake and were more food insecure because of high levels of poverty, unemployment, and lack of land. Peri-urban dwellers are therefore more sensitive to changes in incomes and food prices because they lack safety nets to absorb income or price shocks as they purchase more, rather than growing their own food. This compromises dietary diversity as they have limited access to diverse foods.
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Voices of the hungry: A qualitative measure of household food access and food insecurity in South Africa
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398443 , vital:69412 , xlink:href="https://doi.org/10.1186/s40066-017-0149-x"
- Description: South Africa is rated a food secure nation, but large numbers of households within the country have inadequate access to nutrient-rich diverse foods. The study sought to investigate households’ physical and economic access and availability of food, in relation to local context which influences households’ access to and ability to grow food which may affect the dietary quality. We sought to understand self-reported healthy diets, food insecurity from the perspective of people who experienced it, barriers to household food security and perceptions and feelings on food access as well as strategies households use to cope with food shortages and their perceptions on improving household food security.
- Full Text:
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/398443 , vital:69412 , xlink:href="https://doi.org/10.1186/s40066-017-0149-x"
- Description: South Africa is rated a food secure nation, but large numbers of households within the country have inadequate access to nutrient-rich diverse foods. The study sought to investigate households’ physical and economic access and availability of food, in relation to local context which influences households’ access to and ability to grow food which may affect the dietary quality. We sought to understand self-reported healthy diets, food insecurity from the perspective of people who experienced it, barriers to household food security and perceptions and feelings on food access as well as strategies households use to cope with food shortages and their perceptions on improving household food security.
- Full Text:
Local setting influences the quantity of household food waste in mid-sized South African towns
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67289 , vital:29067 , https://doi.org/10.1371/journal.pone.0189407
- Description: publisher version , From Introduction: The world faces a food security challenge with approximately 868 million people undernourished and about two billion people suffering from the negative health consequences of micronutrient deficiencies [1]. Yet, at least one-third of food produced for human consumption is lost or wasted along the food chain between farm and fork [2–7]. Food waste refers to wholesome edible material intended for human consumption, arising at any point in the food supply chain that is instead discarded, lost, degraded or consumed by pests [8]. Food loss is defined as the decrease in food quantity or quality which makes it unfit for human consumption [9]. According to the European Commission [10], food waste is composed of raw or cooked food materials such as vegetable peelings, meat trimmings and spoiled or excess ingredients or prepared food as well as bones, carcasses and organs. However, food waste can be measured only for edible products that are directed to human consumption [6]. Food losses take place at production, postharvest and processing stages in the food supply chain and the food losses that occur at the end of the food chain (retail and final consumption) are called “food waste” [11]. In our study food waste refers to food losses that occur at the end of the food chain (final consumption at household or consumer level) which include edible products that are directed to human consumption and are discarded when not consumed for various reasons. It is related to consumers’ behaviour [6,11] and it includes food loss before, during or after meal preparation in the household. , The research was funded by VW foundation under the Livelihoods Urbanisation and Natural Resources in Africa (LUNA) project through Freiburg University, Germany. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of this manuscript
- Full Text:
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67289 , vital:29067 , https://doi.org/10.1371/journal.pone.0189407
- Description: publisher version , From Introduction: The world faces a food security challenge with approximately 868 million people undernourished and about two billion people suffering from the negative health consequences of micronutrient deficiencies [1]. Yet, at least one-third of food produced for human consumption is lost or wasted along the food chain between farm and fork [2–7]. Food waste refers to wholesome edible material intended for human consumption, arising at any point in the food supply chain that is instead discarded, lost, degraded or consumed by pests [8]. Food loss is defined as the decrease in food quantity or quality which makes it unfit for human consumption [9]. According to the European Commission [10], food waste is composed of raw or cooked food materials such as vegetable peelings, meat trimmings and spoiled or excess ingredients or prepared food as well as bones, carcasses and organs. However, food waste can be measured only for edible products that are directed to human consumption [6]. Food losses take place at production, postharvest and processing stages in the food supply chain and the food losses that occur at the end of the food chain (retail and final consumption) are called “food waste” [11]. In our study food waste refers to food losses that occur at the end of the food chain (final consumption at household or consumer level) which include edible products that are directed to human consumption and are discarded when not consumed for various reasons. It is related to consumers’ behaviour [6,11] and it includes food loss before, during or after meal preparation in the household. , The research was funded by VW foundation under the Livelihoods Urbanisation and Natural Resources in Africa (LUNA) project through Freiburg University, Germany. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of this manuscript
- Full Text:
Voices of the hungry: a qualitative measure of household food access and food insecurity in South Africa
- Chakona, Gamuchirai, Shackleton, Charlie M
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67277 , vital:29066 , https://doi.org/10.1186/s40066-017-0149-x
- Description: publisher version , Background: South Africa is rated a food secure nation, but large numbers of households within the country have inadequate access to nutrient-rich diverse foods. The study sought to investigate households’ physical and economic access and availability of food, in relation to local context which influences households’ access to and ability to grow food which may affect the dietary quality. We sought to understand self-reported healthy diets, food insecurity from the perspective of people who experienced it, barriers to household food security and perceptions and feelings on food access as well as strategies households use to cope with food shortages and their perceptions on improving household food security. Methods: Focus group discussions were conducted along a rural–urban continuum in three South African towns situated along an agro-ecological gradient. Participants were asked about their knowledge of healthy diets, factors influencing their food consumption, their perceptions regarding food insecurity, barriers to food security, coping strategies and solutions to improve access to nutrient-rich foods. Results: A total of 91 people participated in 11 focus groups, with 76% females. The majority of participants aged between 31 and 50 years. Participants were knowledgeable about healthy diets but had limited access to it hence consumed monotonous diets. The perceptions provided insights into the pressing issues of inadequate access to food, food insecurity, coping strategies and ideas on improving food security. The majority of participants reported on experiencing food insecurity and female-headed households, unemployed and orphaned children were most vulnerable. Focus group participants highlighted the complexity of the food system in their communities which relies on own production, collecting from open spaces, donations and to a larger extent purchase, in the context of unemployment, low income, water and land shortages as well as theft. Conclusion: The results provide a significant contribution from a needs assessment perspective from the communities, identify “hidden” constrains in household food access and provide effective future solutions for improving food security in the communities. Government should assist with capacity building, employment creation and providing resources (especially, land and water) for communities to practise agriculture which they all agreed can improve food security.
- Full Text:
- Authors: Chakona, Gamuchirai , Shackleton, Charlie M
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67277 , vital:29066 , https://doi.org/10.1186/s40066-017-0149-x
- Description: publisher version , Background: South Africa is rated a food secure nation, but large numbers of households within the country have inadequate access to nutrient-rich diverse foods. The study sought to investigate households’ physical and economic access and availability of food, in relation to local context which influences households’ access to and ability to grow food which may affect the dietary quality. We sought to understand self-reported healthy diets, food insecurity from the perspective of people who experienced it, barriers to household food security and perceptions and feelings on food access as well as strategies households use to cope with food shortages and their perceptions on improving household food security. Methods: Focus group discussions were conducted along a rural–urban continuum in three South African towns situated along an agro-ecological gradient. Participants were asked about their knowledge of healthy diets, factors influencing their food consumption, their perceptions regarding food insecurity, barriers to food security, coping strategies and solutions to improve access to nutrient-rich foods. Results: A total of 91 people participated in 11 focus groups, with 76% females. The majority of participants aged between 31 and 50 years. Participants were knowledgeable about healthy diets but had limited access to it hence consumed monotonous diets. The perceptions provided insights into the pressing issues of inadequate access to food, food insecurity, coping strategies and ideas on improving food security. The majority of participants reported on experiencing food insecurity and female-headed households, unemployed and orphaned children were most vulnerable. Focus group participants highlighted the complexity of the food system in their communities which relies on own production, collecting from open spaces, donations and to a larger extent purchase, in the context of unemployment, low income, water and land shortages as well as theft. Conclusion: The results provide a significant contribution from a needs assessment perspective from the communities, identify “hidden” constrains in household food access and provide effective future solutions for improving food security in the communities. Government should assist with capacity building, employment creation and providing resources (especially, land and water) for communities to practise agriculture which they all agreed can improve food security.
- Full Text:
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