Influence of argon-implantation on conventional and phototransferred thermoluminescence of synthetic quartz
- Nsengiyumva, S, Chithambo, Makaiko L, Pichon, L
- Authors: Nsengiyumva, S , Chithambo, Makaiko L , Pichon, L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124732 , vital:35656 , DOI: 10.1080/10420150.2016.1194412
- Description: Conventional and phototransferred thermoluminescence of crystalline synthetic quartz implanted with 70 keV Ar ions at fluences in the range 1 × 1014–5 × 1015 ions/cm2 is reported. The glow curves, recorded at 5°C/s from beta-irradiated samples of similar mass, show a prominent peak between 100°C and 120°C. The thermoluminescence intensity of all implanted samples was greater than that of the unimplanted one. The increase in sensitivity is attributed to a corresponding increase in the concentration of point defects, as a result of the implantation, which act as electron traps or recombination centres. Kinetic analysis carried out using the peak shape, whole glow-peak and curve-fitting methods produced values of the activation energy, frequency factor and order of kinetics that are generally independent of implantation fluence. This result suggests that implantation did not necessarily affect the nature of the electron traps. With respect to phototransferred thermoluminescence, it was observed that it only appeared in the sample implanted at the highest fluence of 5 × 1015 ions/cm2. This may be so because the concentration of deep traps produced as a result of implantation at low fluence is too low to give rise to phototransferred thermoluminescence. The intensity of the phototransferred thermoluminescence goes through a peak with illumination time. We attribute this behaviour to the relative concentration of holes at recombination centres and phototransferred electrons at shallow traps.
- Full Text: false
- Authors: Nsengiyumva, S , Chithambo, Makaiko L , Pichon, L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124732 , vital:35656 , DOI: 10.1080/10420150.2016.1194412
- Description: Conventional and phototransferred thermoluminescence of crystalline synthetic quartz implanted with 70 keV Ar ions at fluences in the range 1 × 1014–5 × 1015 ions/cm2 is reported. The glow curves, recorded at 5°C/s from beta-irradiated samples of similar mass, show a prominent peak between 100°C and 120°C. The thermoluminescence intensity of all implanted samples was greater than that of the unimplanted one. The increase in sensitivity is attributed to a corresponding increase in the concentration of point defects, as a result of the implantation, which act as electron traps or recombination centres. Kinetic analysis carried out using the peak shape, whole glow-peak and curve-fitting methods produced values of the activation energy, frequency factor and order of kinetics that are generally independent of implantation fluence. This result suggests that implantation did not necessarily affect the nature of the electron traps. With respect to phototransferred thermoluminescence, it was observed that it only appeared in the sample implanted at the highest fluence of 5 × 1015 ions/cm2. This may be so because the concentration of deep traps produced as a result of implantation at low fluence is too low to give rise to phototransferred thermoluminescence. The intensity of the phototransferred thermoluminescence goes through a peak with illumination time. We attribute this behaviour to the relative concentration of holes at recombination centres and phototransferred electrons at shallow traps.
- Full Text: false
Linking the ‘know-that’ and ‘know-how’ knowledge through games: a quest to evolve the future for science and engineering education
- Vahed, Anisa, McKenna, Sioux, Singh, S
- Authors: Vahed, Anisa , McKenna, Sioux , Singh, S
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66785 , vital:28993 , ISSN 1573-174X , https://doi.org/10.1007/s10734-015-9956-9
- Description: Publisher version , This paper responds to Muller’s notions of ‘knowing-that’ and ‘knowing how’. The paper addresses how educational interventions that are designed in line with targeted discipline-specific subjects can enhance the balance between professional practice and disciplinary knowledge in professionally accredited programmes at universities of technology. The context is a Dental Technology programme at a University of Technology in South Africa. Teaching through discipline-specific games, conceptualised from a game literacies perspective, is proposed as an engaging, interactive pedagogy for learning disciplinary knowledge that potentially encourages access to a particular affinity group. The authors use concepts from Bernstein and Maton to investigate whether epistemic relations or social relations are emphasised through board and digital games designed for two Dental Technology subjects. This paper offers valuable insight into alternative pedagogies that can be adopted into science, technology, engineering, and mathematics education with the aim of paving a pathway towards Muller’s Scenario 3.
- Full Text: false
- Authors: Vahed, Anisa , McKenna, Sioux , Singh, S
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66785 , vital:28993 , ISSN 1573-174X , https://doi.org/10.1007/s10734-015-9956-9
- Description: Publisher version , This paper responds to Muller’s notions of ‘knowing-that’ and ‘knowing how’. The paper addresses how educational interventions that are designed in line with targeted discipline-specific subjects can enhance the balance between professional practice and disciplinary knowledge in professionally accredited programmes at universities of technology. The context is a Dental Technology programme at a University of Technology in South Africa. Teaching through discipline-specific games, conceptualised from a game literacies perspective, is proposed as an engaging, interactive pedagogy for learning disciplinary knowledge that potentially encourages access to a particular affinity group. The authors use concepts from Bernstein and Maton to investigate whether epistemic relations or social relations are emphasised through board and digital games designed for two Dental Technology subjects. This paper offers valuable insight into alternative pedagogies that can be adopted into science, technology, engineering, and mathematics education with the aim of paving a pathway towards Muller’s Scenario 3.
- Full Text: false
Plasmodium falciparum Hep1 is required to prevent the self aggregation of PfHsp70-3
- Nyakundi, David O, Vuko, Loyiso A M, Bentley, Stephen J, Hoppe, Heinrich C, Blatch, Gregory L, Boshoff, Aileen
- Authors: Nyakundi, David O , Vuko, Loyiso A M , Bentley, Stephen J , Hoppe, Heinrich C , Blatch, Gregory L , Boshoff, Aileen
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66109 , vital:28903 , https://doi.org/10.1371/journal.pone.0156446
- Description: publisher version , The majority of mitochondrial proteins are encoded in the nucleus and need to be imported from the cytosol into the mitochondria, and molecular chaperones play a key role in the efficient translocation and proper folding of these proteins in the matrix. One such molecular chaperone is the eukaryotic mitochondrial heat shock protein 70 (Hsp70); however, it is prone to self-aggregation and requires the presence of an essential zinc-finger protein, Hsp70-escort protein 1 (Hep1), to maintain its structure and function. PfHsp70-3, the only Hsp70 predicted to localize in the mitochondria of P. falciparum, may also rely on a Hep1 orthologue to prevent self-aggregation. In this study, we identified a putative Hep1 orthologue in P. falciparum and co-expression of PfHsp70-3 and PfHep1 enhanced the solubility of PfHsp70-3. PfHep1 suppressed the thermally induced aggregation of PfHsp70-3 but not the aggregation of malate dehydrogenase or citrate synthase, thus showing specificity for PfHsp70-3. Zinc ions were indeed essential for maintaining the function of PfHep1, as EDTA chelation abrogated its abilities to suppress the aggregation of PfHsp70-3. Soluble and functional PfHsp70-3, acquired by co-expression with PfHep-1, will facilitate the biochemical characterisation of this particular Hsp70 protein and its evaluation as a drug target for the treatment of malaria. , This work was funded by grants from the National Research Foundation (NRF); grant number 87663 and Deutsche Forschungsgemeinschaft (DFG); grant number LI 402/14-1. D.O.N. is the recipient of academic development and training funds from Mwenge Catholic University, Moshi, Tanzania. S.J.B. is the recipient of an NRF Doctoral Innovation Scholarship.
- Full Text:
- Authors: Nyakundi, David O , Vuko, Loyiso A M , Bentley, Stephen J , Hoppe, Heinrich C , Blatch, Gregory L , Boshoff, Aileen
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66109 , vital:28903 , https://doi.org/10.1371/journal.pone.0156446
- Description: publisher version , The majority of mitochondrial proteins are encoded in the nucleus and need to be imported from the cytosol into the mitochondria, and molecular chaperones play a key role in the efficient translocation and proper folding of these proteins in the matrix. One such molecular chaperone is the eukaryotic mitochondrial heat shock protein 70 (Hsp70); however, it is prone to self-aggregation and requires the presence of an essential zinc-finger protein, Hsp70-escort protein 1 (Hep1), to maintain its structure and function. PfHsp70-3, the only Hsp70 predicted to localize in the mitochondria of P. falciparum, may also rely on a Hep1 orthologue to prevent self-aggregation. In this study, we identified a putative Hep1 orthologue in P. falciparum and co-expression of PfHsp70-3 and PfHep1 enhanced the solubility of PfHsp70-3. PfHep1 suppressed the thermally induced aggregation of PfHsp70-3 but not the aggregation of malate dehydrogenase or citrate synthase, thus showing specificity for PfHsp70-3. Zinc ions were indeed essential for maintaining the function of PfHep1, as EDTA chelation abrogated its abilities to suppress the aggregation of PfHsp70-3. Soluble and functional PfHsp70-3, acquired by co-expression with PfHep-1, will facilitate the biochemical characterisation of this particular Hsp70 protein and its evaluation as a drug target for the treatment of malaria. , This work was funded by grants from the National Research Foundation (NRF); grant number 87663 and Deutsche Forschungsgemeinschaft (DFG); grant number LI 402/14-1. D.O.N. is the recipient of academic development and training funds from Mwenge Catholic University, Moshi, Tanzania. S.J.B. is the recipient of an NRF Doctoral Innovation Scholarship.
- Full Text:
Possible futures for science and engineering education
- Blackie, Margaret A L, Le Roux, Kate, McKenna, Sioux
- Authors: Blackie, Margaret A L , Le Roux, Kate , McKenna, Sioux
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66796 , vital:28994 , ISSN 1573-174X , https://doi.org/10.1007/s10734-015-9962-y
- Description: Publisher version , From Introduction: The understanding that the science, engineering, technology and mathematics disciplines (STEM) have a significant and directly causal role to play in economic productivity and innovation has driven an increased focus on these fields in higher education. Innovation in this context is a shorthand for the harnessing of the knowledge economy and the provision of products with novel significant ‘added value’. The assumption in both developed and developing economies alike is that STEM will drive national growth (World Bank 2002; UNESCO 2009), and this impacts on demands that universities provide competent graduates in sufficient numbers. However, exactly what ‘competency’ might mean in this context is open to debate.
- Full Text: false
- Authors: Blackie, Margaret A L , Le Roux, Kate , McKenna, Sioux
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66796 , vital:28994 , ISSN 1573-174X , https://doi.org/10.1007/s10734-015-9962-y
- Description: Publisher version , From Introduction: The understanding that the science, engineering, technology and mathematics disciplines (STEM) have a significant and directly causal role to play in economic productivity and innovation has driven an increased focus on these fields in higher education. Innovation in this context is a shorthand for the harnessing of the knowledge economy and the provision of products with novel significant ‘added value’. The assumption in both developed and developing economies alike is that STEM will drive national growth (World Bank 2002; UNESCO 2009), and this impacts on demands that universities provide competent graduates in sufficient numbers. However, exactly what ‘competency’ might mean in this context is open to debate.
- Full Text: false
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