Photophysics and NLO properties of Ga (III) and In (III) phthalocyaninates bearing diethyleneglycol chains
- Managa, Muthumuni, Khene, Samson M, Britton, Jonathan, Martynov, Alexander G, Gorbunova, Yulia G, Tsivadze, Aslan Y, Nyokong, Tebello
- Authors: Managa, Muthumuni , Khene, Samson M , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Y , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237822 , vital:50556 , xlink:href="https://doi.org/10.1142/S1088424618500128"
- Description: This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2′′-(2′′′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxy phthalocyanine (1H2) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.
- Full Text:
- Date Issued: 2018
- Authors: Managa, Muthumuni , Khene, Samson M , Britton, Jonathan , Martynov, Alexander G , Gorbunova, Yulia G , Tsivadze, Aslan Y , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/237822 , vital:50556 , xlink:href="https://doi.org/10.1142/S1088424618500128"
- Description: This work reports on synthesis and characterizations of Ga(III) and In(III) complexes, formed by 2,3-bis[2′′-(2′′′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxy phthalocyanine (1H2) coordinating acetatoindium(III) (1InOAc) and hydroxogallium(III) (1GaOH) Photophysical properties of hydroxogallium(III) phthalocyaninate 1GaOH and acetatoindium(III) phthalocyaninate 1InOAc were studied by UV-vis, fluorescence spectroscopy and time-resolved methods. The nonlinear absorption of the complexes was studied using the Z-scan technique at 532 nm and 10 ns pulse in DMSO and in thin films formed by composite with poly(bisphenol A carbonate) — PBC. The magnitude of absorption coefficients and other nonlinear optical parameters estimated in this work showed that complex 1InOAc exhibited the strongest nonlinear optical behavior in comparison with 1GaOH in solution and a reverse tendency when embedded in PBC thin films. DFT calculations were used to rationalize these results.
- Full Text:
- Date Issued: 2018
Phototransferred thermoluminescence and thermally-assisted optically stimulated luminescence dosimetry using α-Al2O3:C,Mg annealed at 1200°C
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/105422 , vital:32511 , https://doi.org/10.1016/j.jlumin.2018.08.085
- Description: We report phototransferred thermoluminescence (PTTL) and thermally-assisted optically stimulated luminescence (TA-OSL) of α-Al2O3:C,Mg annealed at 1200 °C. PTTL is TL measured from an irradiated phosphor after its exposure to light. The other theme of this study, TA-OSL is the additional amount of luminescence optically stimulated from a sample over and above the amount that would be measured at room temperature. A sample irradiated to 10 Gy and preheated to 230 °C at 1 °C/s followed by illumination by 470 nm blue light produced four PTTL peaks at 53, 80, 102 and 173 °C. The PTTL peaks occur at the same positions as the corresponding conventional TL peaks. Their kinetic parameters are also similar. The intensity of the PTTL peaks increased with duration of illumination to a maximum within 200 s for doses between 1 Gy and 10 Gy. The dose response of each of the PTTL peaks at 80, 102 and 173 °C is linear within 1–15 Gy. The rate of fading is low and the peaks are reproducible. When the irradiated sample is optically stimulated at temperatures between 30 °C and 300 °C, after preheating to 500 °C, the intensity of its TA-OSL goes through a peak with temperature at 200 °C. Using the rising edge of the plot, activation energy of thermal assistance for a deep electron trap was estimated as (0.21 ± 0.02) eV. The TA-OSL dose response is sublinear from 10–250 Gy and saturates thereafter. The PTTL and TA-OSL analyses signify that the concentration of deep traps in α-Al2O3:C,Mg increased after annealing at 1200 °C. As a result, the sample produced better PTTL and TA-OSL response than when annealed at lower temperature.
- Full Text: false
- Date Issued: 2018
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/105422 , vital:32511 , https://doi.org/10.1016/j.jlumin.2018.08.085
- Description: We report phototransferred thermoluminescence (PTTL) and thermally-assisted optically stimulated luminescence (TA-OSL) of α-Al2O3:C,Mg annealed at 1200 °C. PTTL is TL measured from an irradiated phosphor after its exposure to light. The other theme of this study, TA-OSL is the additional amount of luminescence optically stimulated from a sample over and above the amount that would be measured at room temperature. A sample irradiated to 10 Gy and preheated to 230 °C at 1 °C/s followed by illumination by 470 nm blue light produced four PTTL peaks at 53, 80, 102 and 173 °C. The PTTL peaks occur at the same positions as the corresponding conventional TL peaks. Their kinetic parameters are also similar. The intensity of the PTTL peaks increased with duration of illumination to a maximum within 200 s for doses between 1 Gy and 10 Gy. The dose response of each of the PTTL peaks at 80, 102 and 173 °C is linear within 1–15 Gy. The rate of fading is low and the peaks are reproducible. When the irradiated sample is optically stimulated at temperatures between 30 °C and 300 °C, after preheating to 500 °C, the intensity of its TA-OSL goes through a peak with temperature at 200 °C. Using the rising edge of the plot, activation energy of thermal assistance for a deep electron trap was estimated as (0.21 ± 0.02) eV. The TA-OSL dose response is sublinear from 10–250 Gy and saturates thereafter. The PTTL and TA-OSL analyses signify that the concentration of deep traps in α-Al2O3:C,Mg increased after annealing at 1200 °C. As a result, the sample produced better PTTL and TA-OSL response than when annealed at lower temperature.
- Full Text: false
- Date Issued: 2018
Phototransferred thermoluminescence of synthetic quartz: analysis of illumination-time response curves
- Chithambo, Makaiko L, Niyonzima, P, Kalita, Jitumani M
- Authors: Chithambo, Makaiko L , Niyonzima, P , Kalita, Jitumani M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/111020 , vital:33364 , https://doi.org/10.1016/j.jlumin.2018.02.029
- Description: Phototransferred thermoluminescence (PTTL) induced in synthetic quartz by 470 nm blue light is reported. The glow curve measured at 5 °C/s up to 500 °C after irradiation to 100 Gy shows six peaks at 94, 116, 175, 212, 280 and 348 °C labelled I through VI and another one at 80 °C (labelled A1). PTTL is only observed for peaks A1 and I and is induced at peak A1 as long as peak III has been removed by preheating and at peak I after preheating to deplete peak VI. The inducement of PTTL even when all peaks have been removed points to deep electron traps in the quartz also acting as donors in addition to the putative ones below 500 °C. The PTTL intensity as a function of duration of illumination for A1 goes through a peak and decreases monotonically or to a stable value depending on the preheating temperature. The change of PTTL intensity as a function of illumination time is described using a set of coupled linear differential equations. The number of acceptors and donors in a particular system described in this way is influenced by the preheating temperature.
- Full Text: false
- Date Issued: 2018
- Authors: Chithambo, Makaiko L , Niyonzima, P , Kalita, Jitumani M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/111020 , vital:33364 , https://doi.org/10.1016/j.jlumin.2018.02.029
- Description: Phototransferred thermoluminescence (PTTL) induced in synthetic quartz by 470 nm blue light is reported. The glow curve measured at 5 °C/s up to 500 °C after irradiation to 100 Gy shows six peaks at 94, 116, 175, 212, 280 and 348 °C labelled I through VI and another one at 80 °C (labelled A1). PTTL is only observed for peaks A1 and I and is induced at peak A1 as long as peak III has been removed by preheating and at peak I after preheating to deplete peak VI. The inducement of PTTL even when all peaks have been removed points to deep electron traps in the quartz also acting as donors in addition to the putative ones below 500 °C. The PTTL intensity as a function of duration of illumination for A1 goes through a peak and decreases monotonically or to a stable value depending on the preheating temperature. The change of PTTL intensity as a function of illumination time is described using a set of coupled linear differential equations. The number of acceptors and donors in a particular system described in this way is influenced by the preheating temperature.
- Full Text: false
- Date Issued: 2018
Physicochemical properties of water soluble unsymmetrical phthalocyanine-folic acid conjugates
- Matlou, Gauta G, Kobayashi, Nagao, Kimura, Mutsumi, Nyokong, Tebello
- Authors: Matlou, Gauta G , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233240 , vital:50071 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.10.030"
- Description: This work reports on the successful chemical linkage of folic acid (FA) to Zn mono carboxyphenoxy phthalocyanine (1) and Zn mono carboxyphenoxy tri–(tert–butyl) phthalocyanine (2). The amide bond linkage of FA to phthalocyanine (Pc) is achieved for the first time through the FA-NH2 and Pc-COOH and confirmed using FTIR, MS, elemental analysis and NMR. The linked conjugates were found to be water soluble compared to the physical mixtures of FA and Pc, which allowed for studies of singlet oxygen in water. The Pc-FA linked conjugates (1-FA and 2-FA) were found to be singlet oxygen generators with the following singlet oxygen quantum yields: 1-FA = 0.61 and 2-FA = 0.47 in DMSO and 1-FA = 0.17 and 2-FA = 0.12 in water.
- Full Text:
- Date Issued: 2018
- Authors: Matlou, Gauta G , Kobayashi, Nagao , Kimura, Mutsumi , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233240 , vital:50071 , xlink:href="https://doi.org/10.1016/j.dyepig.2017.10.030"
- Description: This work reports on the successful chemical linkage of folic acid (FA) to Zn mono carboxyphenoxy phthalocyanine (1) and Zn mono carboxyphenoxy tri–(tert–butyl) phthalocyanine (2). The amide bond linkage of FA to phthalocyanine (Pc) is achieved for the first time through the FA-NH2 and Pc-COOH and confirmed using FTIR, MS, elemental analysis and NMR. The linked conjugates were found to be water soluble compared to the physical mixtures of FA and Pc, which allowed for studies of singlet oxygen in water. The Pc-FA linked conjugates (1-FA and 2-FA) were found to be singlet oxygen generators with the following singlet oxygen quantum yields: 1-FA = 0.61 and 2-FA = 0.47 in DMSO and 1-FA = 0.17 and 2-FA = 0.12 in water.
- Full Text:
- Date Issued: 2018
Plant–herbivore–parasitoid interactions in an experimental freshwater tritrophic system: higher trophic levels modify competitive interactions between invasive macrophytes
- Martin, Grant D, Coetzee, Julie A, Compton, Stephen
- Authors: Martin, Grant D , Coetzee, Julie A , Compton, Stephen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125686 , vital:35808 , https://doi.org/10.1007/s10750-017-341
- Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwatersystems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and reestablished the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
- Full Text:
- Date Issued: 2018
- Authors: Martin, Grant D , Coetzee, Julie A , Compton, Stephen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125686 , vital:35808 , https://doi.org/10.1007/s10750-017-341
- Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwatersystems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and reestablished the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
- Full Text:
- Date Issued: 2018
Plant–herbivore–parasitoid interactions in an experimental freshwater tritrophic system: higher trophic levels modify competitive interactions between invasive macrophytes
- Martin, Grant D, Coetzee, Julie A, Compton, Stephen
- Authors: Martin, Grant D , Coetzee, Julie A , Compton, Stephen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103892 , vital:32321 , https://doi.org/10.1007/s10750-017-3417-7
- Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwater systems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and re-established the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
- Full Text:
- Date Issued: 2018
- Authors: Martin, Grant D , Coetzee, Julie A , Compton, Stephen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103892 , vital:32321 , https://doi.org/10.1007/s10750-017-3417-7
- Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwater systems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and re-established the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
- Full Text:
- Date Issued: 2018
Point-of-care and lung ultrasound incorporated in daily practice
- Neethling, E, Roodt, F, Beck, C, Swanevelder, J L C
- Authors: Neethling, E , Roodt, F , Beck, C , Swanevelder, J L C
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5248 , vital:44424 , http://www.samj.org.za/index.php/samj/article/view/12293
- Description: Point-of-care ultrasound (POCUS) is a fast-growing clinical utility and is becoming an essential clinical skill for all practitioners attending to critically ill patients. Ultrasound equipment is now smaller, more affordable and readily available in clinical work areas. POCUS is performed by a non-cardiologist physician at the patient’s bedside as an adjunct to the physical examination. It is easily taught, non-invasive and allows for real-time clinical information. Bedside use of ultrasound imaging aids with rapid diagnosis of severe and life-threatening pathological conditions. It can be repeated, may change clinical management, and impact on patient outcome. POCUS has a broad clinical use, including, but not limited to, focused assessed transthoracic echocardiography (FATE), lung ultrasound imaging, extended focused assessment with sonography for trauma (e-FAST), vascular access and regional blocks. It may also be extended to detect endotracheal intubation and the estimation of intracranial pressure. Assessment of cardiac pathology by POCUS, performed by a novice examiner, has been shown to compare with the gold standard of an expert. Training is paramount. The physician should know his limitations and always relate the information back to the clinical scenario and context. By incorporating POCUS as part of our armamentarium and into our daily medical practice, we might see it reach its full clinical potential, optimising patient care and improving patient outcomes.
- Full Text:
- Date Issued: 2018
- Authors: Neethling, E , Roodt, F , Beck, C , Swanevelder, J L C
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5248 , vital:44424 , http://www.samj.org.za/index.php/samj/article/view/12293
- Description: Point-of-care ultrasound (POCUS) is a fast-growing clinical utility and is becoming an essential clinical skill for all practitioners attending to critically ill patients. Ultrasound equipment is now smaller, more affordable and readily available in clinical work areas. POCUS is performed by a non-cardiologist physician at the patient’s bedside as an adjunct to the physical examination. It is easily taught, non-invasive and allows for real-time clinical information. Bedside use of ultrasound imaging aids with rapid diagnosis of severe and life-threatening pathological conditions. It can be repeated, may change clinical management, and impact on patient outcome. POCUS has a broad clinical use, including, but not limited to, focused assessed transthoracic echocardiography (FATE), lung ultrasound imaging, extended focused assessment with sonography for trauma (e-FAST), vascular access and regional blocks. It may also be extended to detect endotracheal intubation and the estimation of intracranial pressure. Assessment of cardiac pathology by POCUS, performed by a novice examiner, has been shown to compare with the gold standard of an expert. Training is paramount. The physician should know his limitations and always relate the information back to the clinical scenario and context. By incorporating POCUS as part of our armamentarium and into our daily medical practice, we might see it reach its full clinical potential, optimising patient care and improving patient outcomes.
- Full Text:
- Date Issued: 2018
Population connectivity of an overexploited coastal fish, Argyrosomus coronus (Sciaenidae), in an ocean-warming hotspot
- Henriques, R, Potts, Warren M, Santos, Carmen V D, Sauer, Warwick H H, Shaw, Paul W
- Authors: Henriques, R , Potts, Warren M , Santos, Carmen V D , Sauer, Warwick H H , Shaw, Paul W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125720 , vital:35811 , https://doi.10.2989/1814232X.2018.1434090
- Description: Anthropogenic activities are recognised as causing significant impacts to marine systems at multiple levels, ranging from habitat disturbance (Pauly et al. 2005) to overfishing (Sala and Knowlton 2006) and loss of genetic diversity (Pinsky and Palumbi 2014). Exploitation and harvesting in particular are known to strongly influence fish populations and their associated ecosystems (Pauly et al. 2005), and in combination with ongoing climate change can have compound effects on the viability and long-term survival of marine fishes (Last et al. 2011). Species can react to the impacts of climate change either by shifting their distributional range or by adapting to changing conditions through individual ecological plasticity and/or local population adaptation (Briggs 2011; Last et al. 2011). However, since ecological plasticity and local adaptation have strong genetic components, overharvesting has the potential to impact the long-term adaptive ability of marine fishes by decreasing the extant genetic diversity (Allendorf et al. 2014). Therefore, understanding the impact of exploitation on genetic diversity and population substructuring is critical for predicting the likely consequences of continued exploitation and climate change.
- Full Text:
- Date Issued: 2018
- Authors: Henriques, R , Potts, Warren M , Santos, Carmen V D , Sauer, Warwick H H , Shaw, Paul W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125720 , vital:35811 , https://doi.10.2989/1814232X.2018.1434090
- Description: Anthropogenic activities are recognised as causing significant impacts to marine systems at multiple levels, ranging from habitat disturbance (Pauly et al. 2005) to overfishing (Sala and Knowlton 2006) and loss of genetic diversity (Pinsky and Palumbi 2014). Exploitation and harvesting in particular are known to strongly influence fish populations and their associated ecosystems (Pauly et al. 2005), and in combination with ongoing climate change can have compound effects on the viability and long-term survival of marine fishes (Last et al. 2011). Species can react to the impacts of climate change either by shifting their distributional range or by adapting to changing conditions through individual ecological plasticity and/or local population adaptation (Briggs 2011; Last et al. 2011). However, since ecological plasticity and local adaptation have strong genetic components, overharvesting has the potential to impact the long-term adaptive ability of marine fishes by decreasing the extant genetic diversity (Allendorf et al. 2014). Therefore, understanding the impact of exploitation on genetic diversity and population substructuring is critical for predicting the likely consequences of continued exploitation and climate change.
- Full Text:
- Date Issued: 2018
Porphyrin dimers with a bridging chiral amide-bonded benzo-moiety
- Liang, Xu, Qin, Mingfeng, Zhou, Lin, Liu, Tingting, Li, Minzhi, Mack, John, Ndebele, Nobuhle, Nyokong, Tebello, Zhu, Weihua
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
- Full Text:
- Date Issued: 2018
- Authors: Liang, Xu , Qin, Mingfeng , Zhou, Lin , Liu, Tingting , Li, Minzhi , Mack, John , Ndebele, Nobuhle , Nyokong, Tebello , Zhu, Weihua
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233433 , vital:50090 , xlink:href="https://doi.org/10.1016/j.dyepig.2018.02.043"
- Description: The facile synthesis and characterization of four porphyrin dimers which introduced stereomeric centers with chiral amide-bonded para- and meta-disubstituted benzo-moiety is reported. Trends in the electronic structures and optical and redox properties are analyzed through a comparison with theoretical calculations to explore the effect of positional isomerism of the bridging benzene rings.
- Full Text:
- Date Issued: 2018
Postgraduate writing groups as spaces of agency development
- Oluwole, David O, Achadu, A, Asfour, Fouad-Martin, Chakona, Gamuchirai, Mason, Paul, Mataruse, P, McKenna, Sioux
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
Potential latitudinal variation in orodigestive tract cancers in Africa
- Adeola, H A, Adefuye, A O, Jimoh, S A
- Authors: Adeola, H A , Adefuye, A O , Jimoh, S A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5280 , vital:44428 , http://www.samj.org.za/index.php/samj/article/view/12259
- Description: Background. Previous studies have alluded to a causal relationship between pathological entities and geographical variations, but there is a paucity of studies from Africa discussing the effect of latitudinal variation on orodigestive cancers in this region. It seems plausible that the burden of orodigestive cancer would differ as a result of variations in diet, cultural habits, climate and environmental conditions down the length of Africa. Objectives. To analyse regional variations in prevalence, incidence and mortality data in the global cancer statistics database (GLOBOCAN 2012) curated by the World Health Organization and the International Agency for Research on Cancer. Basic descriptive statistical tools were used to depict regional variations in cancer morbidity and mortality. Methods. Data on 13 African countries between longitude 20⁰ and 30⁰ east and latitude 35⁰ north and 35⁰ south were examined for variation in age-standardised orodigestive cancer prevalence, incidence and mortality. Possible regional causes for orodigestive tract cancer development were investigated. Data on lip and oral cavity, oesophageal, gastric, colorectal, liver, gallbladder and pancreatic cancers in the 13 countries were compared. Results. Our empirical findings from this preliminary study support the notion that the incidence and prevalence of orodigestive cancers vary within Africa. This effect may be due to environmental, economic, political and possibly genetic factors. Conclusions. Considering the heterogeneity of the above factors across Africa, disbursement of funding for cancer research and therapy in Africa should be focused in terms of regional variations to make best use of the fiscal allocation by African governments, non-governmental organisations and international agencies.
- Full Text:
- Date Issued: 2018
- Authors: Adeola, H A , Adefuye, A O , Jimoh, S A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5280 , vital:44428 , http://www.samj.org.za/index.php/samj/article/view/12259
- Description: Background. Previous studies have alluded to a causal relationship between pathological entities and geographical variations, but there is a paucity of studies from Africa discussing the effect of latitudinal variation on orodigestive cancers in this region. It seems plausible that the burden of orodigestive cancer would differ as a result of variations in diet, cultural habits, climate and environmental conditions down the length of Africa. Objectives. To analyse regional variations in prevalence, incidence and mortality data in the global cancer statistics database (GLOBOCAN 2012) curated by the World Health Organization and the International Agency for Research on Cancer. Basic descriptive statistical tools were used to depict regional variations in cancer morbidity and mortality. Methods. Data on 13 African countries between longitude 20⁰ and 30⁰ east and latitude 35⁰ north and 35⁰ south were examined for variation in age-standardised orodigestive cancer prevalence, incidence and mortality. Possible regional causes for orodigestive tract cancer development were investigated. Data on lip and oral cavity, oesophageal, gastric, colorectal, liver, gallbladder and pancreatic cancers in the 13 countries were compared. Results. Our empirical findings from this preliminary study support the notion that the incidence and prevalence of orodigestive cancers vary within Africa. This effect may be due to environmental, economic, political and possibly genetic factors. Conclusions. Considering the heterogeneity of the above factors across Africa, disbursement of funding for cancer research and therapy in Africa should be focused in terms of regional variations to make best use of the fiscal allocation by African governments, non-governmental organisations and international agencies.
- Full Text:
- Date Issued: 2018
Practice intentions at entry to and exit from medical schools aspiring to social accountability: findings from the Training for Health Equity Network Graduate Outcome Study
- Iputo, Jehu, Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Authors: Iputo, Jehu , Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5415 , vital:44567 , https://pubmed.ncbi.nlm.nih.gov/30424760/
- Description: Background: Understanding the impact of selection and medical education on practice intentions and eventual practice is an essential component of training a fit-for-purpose health workforce distributed according to population need. Existing evidence comes largely from high-income settings and neglects contextual factors. This paper describes the practice intentions of entry and exit cohorts of medical students across low and high income settings and the correlation of student characteristics with these intentions. Methods: The Training for Health Equity Network (THEnet) Graduate Outcome Study (GOS) is an international prospective cohort study tracking learners throughout training and ten years into practice as part of the longitudinal impact assessment described in THEnet’s Evaluation Framework. THEnet is an international community of practice of twelve medical schools with a social accountability mandate. Data presented here include cross-sectional entry and exit data obtained from different cohorts of medical students involving eight medical schools in six countries and five continents. Binary logistic regression was used to create adjusted odds ratios for associations with practice intent. Results: Findings from 3346 learners from eight THEnet medical schools in 6 countries collected between 2012 and 2016 are presented. A high proportion of study respondents at these schools come from rural and disadvantaged backgrounds and these respondents are more likely than others to express an intention to work in underserved locations after graduation at both entry and exit from medical school. After adjusting for confounding factors, rural and low income background and regional location of medical school were the most important predictors of intent to practice in a rural location. For schools in the Philippines and Africa, intention to emigrate was more likely for respondents from high income and urban backgrounds.
- Full Text:
- Date Issued: 2018
- Authors: Iputo, Jehu , Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5415 , vital:44567 , https://pubmed.ncbi.nlm.nih.gov/30424760/
- Description: Background: Understanding the impact of selection and medical education on practice intentions and eventual practice is an essential component of training a fit-for-purpose health workforce distributed according to population need. Existing evidence comes largely from high-income settings and neglects contextual factors. This paper describes the practice intentions of entry and exit cohorts of medical students across low and high income settings and the correlation of student characteristics with these intentions. Methods: The Training for Health Equity Network (THEnet) Graduate Outcome Study (GOS) is an international prospective cohort study tracking learners throughout training and ten years into practice as part of the longitudinal impact assessment described in THEnet’s Evaluation Framework. THEnet is an international community of practice of twelve medical schools with a social accountability mandate. Data presented here include cross-sectional entry and exit data obtained from different cohorts of medical students involving eight medical schools in six countries and five continents. Binary logistic regression was used to create adjusted odds ratios for associations with practice intent. Results: Findings from 3346 learners from eight THEnet medical schools in 6 countries collected between 2012 and 2016 are presented. A high proportion of study respondents at these schools come from rural and disadvantaged backgrounds and these respondents are more likely than others to express an intention to work in underserved locations after graduation at both entry and exit from medical school. After adjusting for confounding factors, rural and low income background and regional location of medical school were the most important predictors of intent to practice in a rural location. For schools in the Philippines and Africa, intention to emigrate was more likely for respondents from high income and urban backgrounds.
- Full Text:
- Date Issued: 2018
Price determination of non-timber forest products in different areas of South Africa
- Mugido, Worship, Shackleton, Charlie M
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179825 , vital:43192 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.12.010"
- Description: A wide variety of factors can influence the price determination of non-timber forest products (NTFPs) in individual markets. However, there is little understanding of differences across multiple markets within a uniform macro context, or how they might vary between different types of NTFPs. Therefore, this study sought to determine the factors and rationale behind the setting of prices for selected NTFPs in 15 different areas of South Africa. The results showed that the pricing factors considered by sellers when setting the prices of NTFP varied with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. Overall, transport costs, stock price, profit margin, time taken to collect or produce the product and market price were the widely used factors to determine prices for NTFPs. The marked variation in both markets and products show that there was no formal or certain price setting mechanism that was used by NTFP sellers establish the market prices of NTFPs, with price discovery being the most widespread.
- Full Text:
- Date Issued: 2018
- Authors: Mugido, Worship , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179825 , vital:43192 , xlink:href="https://doi.org/10.1016/j.ecolecon.2017.12.010"
- Description: A wide variety of factors can influence the price determination of non-timber forest products (NTFPs) in individual markets. However, there is little understanding of differences across multiple markets within a uniform macro context, or how they might vary between different types of NTFPs. Therefore, this study sought to determine the factors and rationale behind the setting of prices for selected NTFPs in 15 different areas of South Africa. The results showed that the pricing factors considered by sellers when setting the prices of NTFP varied with the type of NTFP being sold, type of market (home markets or urban markets) and the method used by the seller to procure the stock. Overall, transport costs, stock price, profit margin, time taken to collect or produce the product and market price were the widely used factors to determine prices for NTFPs. The marked variation in both markets and products show that there was no formal or certain price setting mechanism that was used by NTFP sellers establish the market prices of NTFPs, with price discovery being the most widespread.
- Full Text:
- Date Issued: 2018
Pro-Environmental behaviour in student residences at Rhodes University, South Africa:
- Thondhlana, Gladman, Hlatshwayo, Thina N
- Authors: Thondhlana, Gladman , Hlatshwayo, Thina N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144288 , vital:38328 , https://doi.org/10.3390/su10082746
- Description: Human behaviour is at the centre of most environmental problems; hence, the promotion of pro-environmental behaviour is considered to be a pathway towards sustainability. Despite the availability of insights gained from pro-environmental behaviour studies, mainly from household and workplace settings, a key question remains—can these insights be applied in university residence settings? Within university campuses, student residences are a major entity in sustainability debates because they are major consumers of resources including paper, water and energy with severe repercussions for university budgets and the environment. Using a questionnaire survey, this study explores reported pro-environmental behaviour and its determinants at Rhodes University, South Africa. Data were analysed using descriptive and inferential statistics where relevant. The findings show a high level of heterogeneity in reported pro-environmental behaviour, attributed to a suite of internal and external factors. Internal dispositional factors seemed to constrain students from acting pro-environmentally. This study highlights the need to encourage environmental behaviour in university residence settings by supporting the antecedents of and getting rid of barriers to pro-environmental actions.
- Full Text:
- Date Issued: 2018
- Authors: Thondhlana, Gladman , Hlatshwayo, Thina N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144288 , vital:38328 , https://doi.org/10.3390/su10082746
- Description: Human behaviour is at the centre of most environmental problems; hence, the promotion of pro-environmental behaviour is considered to be a pathway towards sustainability. Despite the availability of insights gained from pro-environmental behaviour studies, mainly from household and workplace settings, a key question remains—can these insights be applied in university residence settings? Within university campuses, student residences are a major entity in sustainability debates because they are major consumers of resources including paper, water and energy with severe repercussions for university budgets and the environment. Using a questionnaire survey, this study explores reported pro-environmental behaviour and its determinants at Rhodes University, South Africa. Data were analysed using descriptive and inferential statistics where relevant. The findings show a high level of heterogeneity in reported pro-environmental behaviour, attributed to a suite of internal and external factors. Internal dispositional factors seemed to constrain students from acting pro-environmentally. This study highlights the need to encourage environmental behaviour in university residence settings by supporting the antecedents of and getting rid of barriers to pro-environmental actions.
- Full Text:
- Date Issued: 2018
Prospects for biological control of cactus weeds in Namibia
- Paterson, Iain D, Manheimmer, C A, Zimmermann, H C
- Authors: Paterson, Iain D , Manheimmer, C A , Zimmermann, H C
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417522 , vital:71460 , xlink:href="https://doi.org/10.1080/09583157.2018.1562040"
- Description: Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.
- Full Text:
- Date Issued: 2018
- Authors: Paterson, Iain D , Manheimmer, C A , Zimmermann, H C
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417522 , vital:71460 , xlink:href="https://doi.org/10.1080/09583157.2018.1562040"
- Description: Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.
- Full Text:
- Date Issued: 2018
Protection of internally displaced persons in Kenya under the Prevention, Protection and Assistance to Internally Displaced Persons and Affected Communities Act of 2012: an appraisal
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126122 , vital:35851 , https://hdl.handle.net/10520/EJC-107c9cba58
- Description: This article discusses Kenya’s Prevention, Protection and Assistance to Internally Displaced Persons and Affected Communities Act of 2012, which is among the very few national legislations globally that addresses the plight of internally displaced persons. While it records the momentous achievement in creating a viable and legally enforceable legislative framework for the protection of IDPs, the article highlights some of the areas that could be improved for the Act to realise its promise. It notes for example the inchoate manner in which institutions are created and the lack of resources. The article while isolating these challenges also suggests numerous ways in which such challenges can be overcome. It underscores the need for harmonised legal regimes, improvement of data collection and proper monitoring programmes, all which can be achieved and strengthened by a supportive political establishment as well as strategic amendments to various provisions of the Act.
- Full Text: false
- Date Issued: 2018
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126122 , vital:35851 , https://hdl.handle.net/10520/EJC-107c9cba58
- Description: This article discusses Kenya’s Prevention, Protection and Assistance to Internally Displaced Persons and Affected Communities Act of 2012, which is among the very few national legislations globally that addresses the plight of internally displaced persons. While it records the momentous achievement in creating a viable and legally enforceable legislative framework for the protection of IDPs, the article highlights some of the areas that could be improved for the Act to realise its promise. It notes for example the inchoate manner in which institutions are created and the lack of resources. The article while isolating these challenges also suggests numerous ways in which such challenges can be overcome. It underscores the need for harmonised legal regimes, improvement of data collection and proper monitoring programmes, all which can be achieved and strengthened by a supportive political establishment as well as strategic amendments to various provisions of the Act.
- Full Text: false
- Date Issued: 2018
Protection of rights of urban refugees in Kenya: revisiting Kituo Cha Sheria v The Attorney General
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125174 , vital:35740 , DOI: 10.25159/2522-6800/3291
- Description: This article discusses the judgment in the landmark case of Kituo Cha Sheria and Others v Attorney General in the light of the emerging rights jurisprudence in the area of refugee rights. It also explores the impact the judgment could have on the articulation of the rights of urban refugees in Kenya. Based on the assumption that Kenya’s 2010 Constitution provides an opportunity for the robust enforcement of rights, the article analyses the key rights and protection imperatives that were at the centre of the dispute. These include the right to dignity, freedom of movement and to work, and also the principle of refoulement. These rights are at the core of the protection agenda for urban refugees.
- Full Text: false
- Date Issued: 2018
- Authors: Juma, Laurence
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125174 , vital:35740 , DOI: 10.25159/2522-6800/3291
- Description: This article discusses the judgment in the landmark case of Kituo Cha Sheria and Others v Attorney General in the light of the emerging rights jurisprudence in the area of refugee rights. It also explores the impact the judgment could have on the articulation of the rights of urban refugees in Kenya. Based on the assumption that Kenya’s 2010 Constitution provides an opportunity for the robust enforcement of rights, the article analyses the key rights and protection imperatives that were at the centre of the dispute. These include the right to dignity, freedom of movement and to work, and also the principle of refoulement. These rights are at the core of the protection agenda for urban refugees.
- Full Text: false
- Date Issued: 2018
Pyridone substituted phthalocyanines: Photophysico-chemical properties and TD-DFT calculations
- Abdurrahmanoğlu, Şaziye, Canlica, Mevlüde, Mack, John, Nyokong, Tebello
- Authors: Abdurrahmanoğlu, Şaziye , Canlica, Mevlüde , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188216 , vital:44735 , xlink:href="https://doi.org/10.1142/S1088424617500730"
- Description: 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and 11H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.
- Full Text:
- Date Issued: 2018
- Authors: Abdurrahmanoğlu, Şaziye , Canlica, Mevlüde , Mack, John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188216 , vital:44735 , xlink:href="https://doi.org/10.1142/S1088424617500730"
- Description: 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile has been used to prepare a novel Zn(II) phthalocyanines with four peripheral pyridone substituents. The compound has been characterized by UV-visible absorption, FT-IR and 11H-NMR spectroscopy, elemental analysis and MALDI-TOF mass spectroscopy. The fluorescence, triplet quantum and singlet oxygen quantum yields have been determined and TD-DFT calculations have been used to identify trends in the electronic structure.
- Full Text:
- Date Issued: 2018
Quantitation of zolpidem in biological fluids by electro-driven microextraction combined with HPLC-UV analysis
- Yaripour, Saeid, Mohammadi, Ali, Esfanjani, Isa, Walker, Roderick B, Nojavan, Saeed
- Authors: Yaripour, Saeid , Mohammadi, Ali , Esfanjani, Isa , Walker, Roderick B , Nojavan, Saeed
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184723 , vital:44266 , xlink:href="http://dx.doi.org/10.17179/excli2018-1140"
- Description: In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R2 >0.9991) with repeatability (%RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.
- Full Text:
- Date Issued: 2018
- Authors: Yaripour, Saeid , Mohammadi, Ali , Esfanjani, Isa , Walker, Roderick B , Nojavan, Saeed
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184723 , vital:44266 , xlink:href="http://dx.doi.org/10.17179/excli2018-1140"
- Description: In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R2 >0.9991) with repeatability (%RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.
- Full Text:
- Date Issued: 2018
Real-time geotagging and filtering of network data using a heterogeneous NPU-CPU architecture
- Pennefather, Sean, Bradshaw, Karen L, Irwin, Barry V W
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427726 , vital:72458 , https://www.researchgate.net/profile/Barry-Irwin/publication/327630459_Real-Time_Geotagging_and_Filtering_of_Network_Data_using_a_Heterogeneous_NPU-CPU_Architecture/links/5b9a69d145851574f7c3d3b7/Real-Time-Geotagging-and-Filtering-of-Network-Data-using-a-Heterogeneous-NPU-CPU-Architecture.pdf
- Description: In this paper, we present the design and implementation of a NPU-CPU heterogeneous network monitoring application. This application allows for both filtering and monitoring operations to be performed on network traffic based on country of origin or destination of IP traffic in real-time at wire speeds up to 1 Gbit/s. This is achievable by distributing the application components to the relevant candidate architectures, leveraging the strengths of each. Communication between architectures is handled at runtime by a low latency synchronous message passing library. Testing of the implemented application indicates that the system can perform geolocation lookups on network traffic in real-time without impacting network throughput.
- Full Text:
- Date Issued: 2018
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427726 , vital:72458 , https://www.researchgate.net/profile/Barry-Irwin/publication/327630459_Real-Time_Geotagging_and_Filtering_of_Network_Data_using_a_Heterogeneous_NPU-CPU_Architecture/links/5b9a69d145851574f7c3d3b7/Real-Time-Geotagging-and-Filtering-of-Network-Data-using-a-Heterogeneous-NPU-CPU-Architecture.pdf
- Description: In this paper, we present the design and implementation of a NPU-CPU heterogeneous network monitoring application. This application allows for both filtering and monitoring operations to be performed on network traffic based on country of origin or destination of IP traffic in real-time at wire speeds up to 1 Gbit/s. This is achievable by distributing the application components to the relevant candidate architectures, leveraging the strengths of each. Communication between architectures is handled at runtime by a low latency synchronous message passing library. Testing of the implemented application indicates that the system can perform geolocation lookups on network traffic in real-time without impacting network throughput.
- Full Text:
- Date Issued: 2018