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
Students as Agents of Social Change-Student Initiatives at Rhodes University, South Africa
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
Improved Photophysical and Photochemical Properties of Thiopheneethoxy Substituted Metallophthalocyanines on Immobilization onto Gold‐speckled Silica Nanoparticles
- Dube, Edith, Oluwole, David O, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
Electrochemical, microscopic and spectroscopic characterization of benzene diamine functionalized single walled carbon nanotube-cobalt (II) tetracarboxy-phthalocyanine conjugates
- Mugadza, Tawanda, Nyokong, Tebello
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
- Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
- Full Text:
- Date Issued: 2011
- Authors: Mugadza, Tawanda , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247859 , vital:51624 , xlink:href="https://doi.org/10.1016/j.jcis.2010.10.057"
- Description: In this paper we report on the synthesis and characterization of 1,4-benzene diamine (BDA) functionalized single walled carbon nanotubes linked to cobalt (II) tetracarboxy-phthalocyanine. The characterization of the conjugate was through UV–vis, FTIR and X-ray diffraction (XRD) spectroscopies and by transmission electron microscope (TEM) and electrochemical methods. The conjugate is used for the electrochemical characterization of diuron. The catalytic rate constant for diuron was 4.4 × 103 M−1 s−1 and the apparent electron transfer rate constant was 18.5 × 10−6 cm s−1. The linear dynamic range was 1.0 × 10−5–2.0 × 10−4 M, with a sensitivity of ∼0.42 A mol−1L cm−2 and a limit of detection of 0.18 μM using the 3δ notation.
- Full Text:
- Date Issued: 2011
Iron perchlorophthalocyanine and tetrasulfophthalocyanine catalyzed oxidation of cyclohexane using hydrogen peroxide, chloroperoxybenzoic acid and tert-butylhydroperoxide as oxidants
- Grootboom, Natasha, Nyokong, Tebello
- Authors: Grootboom, Natasha , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289606 , vital:56653 , xlink:href="https://doi.org/10.1016/S1381-1169(01)00404-6"
- Description: Polychlorophthalocyanine (Cl16PcFeII) and tetrasulfophthalocyanine ([FeIITSPc]4−) complexes of iron are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide as oxidants. Catalysis using the Cl16PcFeII was performed in a dimethylformamide:dichloromethane (3:7) solvent mixture. For the [FeIITSPc]4−catalyst, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative yields of the products depended on oxidant and the catalyst. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. The mechanism of the oxidation of cyclohexane in the presence of the Cl16PcFeII and [FeIITSPc]4− involves the oxidation of these catalysts, forming an Fe(III) phthalocyanine species as an intermediate. Higher yields were observed when [FeTSPc]4− was employed as a catalyst, which is more soluble than the perchlorinated iron phthalocyanine catalyst.
- Full Text:
- Date Issued: 2002
- Authors: Grootboom, Natasha , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289606 , vital:56653 , xlink:href="https://doi.org/10.1016/S1381-1169(01)00404-6"
- Description: Polychlorophthalocyanine (Cl16PcFeII) and tetrasulfophthalocyanine ([FeIITSPc]4−) complexes of iron are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide as oxidants. Catalysis using the Cl16PcFeII was performed in a dimethylformamide:dichloromethane (3:7) solvent mixture. For the [FeIITSPc]4−catalyst, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative yields of the products depended on oxidant and the catalyst. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. The mechanism of the oxidation of cyclohexane in the presence of the Cl16PcFeII and [FeIITSPc]4− involves the oxidation of these catalysts, forming an Fe(III) phthalocyanine species as an intermediate. Higher yields were observed when [FeTSPc]4− was employed as a catalyst, which is more soluble than the perchlorinated iron phthalocyanine catalyst.
- Full Text:
- Date Issued: 2002
Being moved by a way the world is not
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
- Authors: Jones, Ward E
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275631 , vital:55064 , xlink:href="https://doi.org/10.1007/s11229-009-9522-z"
- Description: At the end of Lecture 3 of The Empirical Stance, Bas van Fraassen suggests that we see the change of view involved in scientific revolutions as being, at least in part, emotional. In this paper, I explore one plausible way of cashing out this suggestion. Someone’s emotional approval of a description of the world, I argue, thereby shows that she takes herself to have reason to take that description seriously. This is true even if she is convinced—as a scientific community is when it considers alternative theories—that this description is false, that it is not the way the world is.
- Full Text:
- Date Issued: 2011
(Ferrocenylpyrazolyl) zinc (II) benzoates as catalysts for the ring opening polymerization of ε-caprolactone
- Obuah, Collins, Lochee, Yemanlall, Jordaan, Johan H L, Otto, Daniel P, Nyokong, Tebello, Darkwa, James
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
Water-soluble quaternized mercaptopyridine-substituted zinc-phthalocyanines
- Durmuş, Mahmut, Yaman, Hanif, Göl, Cem, Ahsen, Vefa, Nyokong, Tebello
- Authors: Durmuş, Mahmut , Yaman, Hanif , Göl, Cem , Ahsen, Vefa , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247133 , vital:51549 , xlink:href="https://doi.org/10.1016/j.dyepig.2011.02.007"
- Description: The synthesis and characterization of the new zinc phthalocyanine derivatives, tetra- (non-peripheral, 5) and octa-(peripheral, 6) substituted with 2-mercaptopyridine and their respective quaternized derivatives (8 and 9) are reported. Photochemical and photophysical properties of the new complexes are compared with those of the previously reported peripherally tetra-substituted complexes 7 and 10. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. Spectroscopic, aggregation, photophysical and photochemical properties of these complexes are also investigated and compared. Photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yield) properties of these phthalocyanine photosensitizers are very important for the assessment of these complexes as PDT agents. In this study, the effects of the position of the substituents and quaternization of the substituents on the photophysical and photochemical parameters of the zinc phthalocyanines are also reported. This study also showed that the water-soluble quaternized zinc phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).
- Full Text:
- Date Issued: 2011
- Authors: Durmuş, Mahmut , Yaman, Hanif , Göl, Cem , Ahsen, Vefa , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247133 , vital:51549 , xlink:href="https://doi.org/10.1016/j.dyepig.2011.02.007"
- Description: The synthesis and characterization of the new zinc phthalocyanine derivatives, tetra- (non-peripheral, 5) and octa-(peripheral, 6) substituted with 2-mercaptopyridine and their respective quaternized derivatives (8 and 9) are reported. Photochemical and photophysical properties of the new complexes are compared with those of the previously reported peripherally tetra-substituted complexes 7 and 10. The quaternized compounds exhibit excellent solubility in water, making them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. Spectroscopic, aggregation, photophysical and photochemical properties of these complexes are also investigated and compared. Photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen and photodegradation quantum yield) properties of these phthalocyanine photosensitizers are very important for the assessment of these complexes as PDT agents. In this study, the effects of the position of the substituents and quaternization of the substituents on the photophysical and photochemical parameters of the zinc phthalocyanines are also reported. This study also showed that the water-soluble quaternized zinc phthalocyanines strongly bind to blood plasma proteins such as bovine serum albumin (BSA).
- Full Text:
- Date Issued: 2011
A comparative study of the singlet oxygen generation capability of a zinc phthalocyanine linked to graphene quantum dots through π-π stacking and covalent conjugation when embedded in asymmetric polymer membranes
- Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187461 , vital:44655 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.11.096"
- Description: Following the establishment of graphene quantum dots as potential phthalocyanine supports in photoactive membrane preparation for phthalocyanines lacking linkage functional groups, the practical efficiency of p-p stacking versus covalent linkage was investigated. Synthesized materials were characterized using FT-IR, Raman, powder X-ray diffraction, and UVeVis spectroscopies and also by transmission electron and scanning electron microscopies. Phthalocyanine loadings onto graphene quantum dots of 0.40 mg/mg and 0.14 mg/mg (Pc mass/conjugate mass) for the p-p stacked and covalent linked conjugates respectively were observed. Covalent linkage to graphene quantum dots proved to be functionally superior to p-p linkage, where singlet oxygen quantum yield value of the phthalocyanine in the membrane for the covalent linked conjugate was approximately twice that of the p-p stacked membrane.
- Full Text:
- Date Issued: 2019
- Authors: Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187461 , vital:44655 , xlink:href="https://doi.org/10.1016/j.molstruc.2018.11.096"
- Description: Following the establishment of graphene quantum dots as potential phthalocyanine supports in photoactive membrane preparation for phthalocyanines lacking linkage functional groups, the practical efficiency of p-p stacking versus covalent linkage was investigated. Synthesized materials were characterized using FT-IR, Raman, powder X-ray diffraction, and UVeVis spectroscopies and also by transmission electron and scanning electron microscopies. Phthalocyanine loadings onto graphene quantum dots of 0.40 mg/mg and 0.14 mg/mg (Pc mass/conjugate mass) for the p-p stacked and covalent linked conjugates respectively were observed. Covalent linkage to graphene quantum dots proved to be functionally superior to p-p linkage, where singlet oxygen quantum yield value of the phthalocyanine in the membrane for the covalent linked conjugate was approximately twice that of the p-p stacked membrane.
- Full Text:
- Date Issued: 2019
Photo-induced resonance energy transfer and nonlinear optical response in ball-type phthalocyanine conjugated to semiconductor and graphene quantum dots
- Nwaji, Njemuwa, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Nwaji, Njemuwa , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187959 , vital:44713 , xlink:href="https://doi.org/10.1039/C7NJ05196D"
- Description: The synthesis of ball-type zinc and gallium phthalocyanines (complexes 2 and 3) and their covalent linkage to glutathione (GSH) and amine functionalized quantum dots QDs) are reported in this work. Furthermore, their photophysical, photo-induced resonance energy transfer and optical limiting responses were investigated. We observed a decrease in the fluorescence quantum yields with a corresponding increase in the triplet quantum yields of the nanoconjugates in comparison to the phthalocyanine complexes alone. The reverse saturable absorption was found to be dependent on the excited state absorption, and the observed limiting threshold ranged from 0.32 to 1.43 J cm−2. Enhanced triplet parameters and nonlinear optical performance were found when the complexes were covalently linked to semiconductor quantum dots compared to carbon based graphene quantum dots.
- Full Text:
- Date Issued: 2018
- Authors: Nwaji, Njemuwa , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187959 , vital:44713 , xlink:href="https://doi.org/10.1039/C7NJ05196D"
- Description: The synthesis of ball-type zinc and gallium phthalocyanines (complexes 2 and 3) and their covalent linkage to glutathione (GSH) and amine functionalized quantum dots QDs) are reported in this work. Furthermore, their photophysical, photo-induced resonance energy transfer and optical limiting responses were investigated. We observed a decrease in the fluorescence quantum yields with a corresponding increase in the triplet quantum yields of the nanoconjugates in comparison to the phthalocyanine complexes alone. The reverse saturable absorption was found to be dependent on the excited state absorption, and the observed limiting threshold ranged from 0.32 to 1.43 J cm−2. Enhanced triplet parameters and nonlinear optical performance were found when the complexes were covalently linked to semiconductor quantum dots compared to carbon based graphene quantum dots.
- Full Text:
- Date Issued: 2018
Improved photocatalytic degradation of Orange G using hybrid nanofibers
- Ledwaba, Mpho, Masilela, Nkosiphile, Nyokong, Tebello, Antunes, Edith M
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239632 , vital:50750 , xlink:href="https://doi.org/10.1007/s11051-017-3853-3"
- Description: Functionalised electrospun polyamide-6 (PA-6) nanofibres incorporating gadolinium oxide nanoparticles conjugated to zinc tetracarboxyphenoxy phthalocyanine (ZnTCPPc) as the sensitizer were prepared for the photocatalytic degradation of Orange G. Fibres incorporating the phthalocyanine alone or a mixture of the nanoparticles and phthalocyanine were also generated. The singlet oxygen-generating ability of the sensitizer was shown to be maintained within the fibre mat, with the singlet oxygen quantum yields increasing upon incorporation of the magnetic nanoparticles. Consequently, the rate of the photodegradation of Orange G was observed to increase with an increase in singlet oxygen quantum yield. A reduction in the half-lives for the functionalised nanofibres was recorded in the presence of the magnetic nanoparticles, indicating an improvement in the efficiency of the degradation process.
- Full Text:
- Date Issued: 2017
- Authors: Ledwaba, Mpho , Masilela, Nkosiphile , Nyokong, Tebello , Antunes, Edith M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239632 , vital:50750 , xlink:href="https://doi.org/10.1007/s11051-017-3853-3"
- Description: Functionalised electrospun polyamide-6 (PA-6) nanofibres incorporating gadolinium oxide nanoparticles conjugated to zinc tetracarboxyphenoxy phthalocyanine (ZnTCPPc) as the sensitizer were prepared for the photocatalytic degradation of Orange G. Fibres incorporating the phthalocyanine alone or a mixture of the nanoparticles and phthalocyanine were also generated. The singlet oxygen-generating ability of the sensitizer was shown to be maintained within the fibre mat, with the singlet oxygen quantum yields increasing upon incorporation of the magnetic nanoparticles. Consequently, the rate of the photodegradation of Orange G was observed to increase with an increase in singlet oxygen quantum yield. A reduction in the half-lives for the functionalised nanofibres was recorded in the presence of the magnetic nanoparticles, indicating an improvement in the efficiency of the degradation process.
- Full Text:
- Date Issued: 2017
Glycosylated zinc phthalocyanine-gold nanoparticle conjugates for photodynamic therapy
- Dube, Edith, Oluwole, David O, Nwaji, Njemuwa, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234524 , vital:50205 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.081"
- Description: In this work, we report on the synthesis of tris-[(2,2,7,7-tetramethyltetrahydro-3aH-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methoxy)-2-(4-benzo[d]thiazol-2-ylphenoxyphthalocyaninato] zinc(II) (complex 3) and its linkage to gold nanoparticles (AuNPs) of different shapes through S-Au/N-Au self-assembly. The conjugates of complex 3 (with both gold nanorods (AuNR) and nanospheres (AuNS)), displayed decreased fluorescence quantum yield with corresponding improved triplet and singlet quantum yields compared to complex 3 alone, however 3-AuNR showed improved properties than 3-AuNS. Complex 3 showed relatively low in vitro dark cytotoxicity against the epithelial breast cancer cells with cell survival ≥ 85% at concentration ≤ 160 μg/mL but afforded reduced photodynamic therapy activity which may be due to aggregation. 3-AuNR afforded superior PDT activity with more than 50% viable cells at concentration ≥ 40 μg/mL in comparison to 3-AuNS with more than 50% viable cells at concentration ≥ 80 μg/mL. The superior activity of 3-AuNR is attributed to the photothermal therapy effect since nanorods absorb more light at 680 nm than nanospheres.
- Full Text:
- Date Issued: 2018
The electrochemical detection of prostate specific antigen on glassy carbon electrode modified with combinations of graphene quantum dots, cobalt phthalocyanine and an aptamer
- Nxele, Siphesihle R, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185013 , vital:44316 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111462"
- Description: Herein, a novel aptasensor is developed for the electrochemical detection of prostate specific antigen (PSA) on electrode surfaces modified using various combinations of a Cobalt phthalocyanine (CoPc), an aptamer and graphene quantum dots (GQDs). Electrochemical impedance spectroscopy (EIS) as well as differential pulse voltammetry (DPV) are employed for the detection of PSA. In both analytical techniques, linear calibration curves were observed at a concentration range of 1.2–2.0 pM. The glassy carbon electrode where CoPc and GQDs are placed on the electrode when non-covalently linked followed by addition of the aptamer (GQDs-CoPc(ππ)-aptamer (sequential)) showed the best performance with a limit of detection (LoD) as low as 0.66 pM when using DPV. The detection limits were much lower than the dangerous levels reported for PSA in males tested for prostate cancer. This electrode showed selectivity for PSA in the presence of bovine serum albumin, glucose and L-cysteine. The aptasensor showed good stability, reproducibility and repeatability, deeming it a promising early detection device for prostate cancer.
- Full Text:
- Date Issued: 2021
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185013 , vital:44316 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111462"
- Description: Herein, a novel aptasensor is developed for the electrochemical detection of prostate specific antigen (PSA) on electrode surfaces modified using various combinations of a Cobalt phthalocyanine (CoPc), an aptamer and graphene quantum dots (GQDs). Electrochemical impedance spectroscopy (EIS) as well as differential pulse voltammetry (DPV) are employed for the detection of PSA. In both analytical techniques, linear calibration curves were observed at a concentration range of 1.2–2.0 pM. The glassy carbon electrode where CoPc and GQDs are placed on the electrode when non-covalently linked followed by addition of the aptamer (GQDs-CoPc(ππ)-aptamer (sequential)) showed the best performance with a limit of detection (LoD) as low as 0.66 pM when using DPV. The detection limits were much lower than the dangerous levels reported for PSA in males tested for prostate cancer. This electrode showed selectivity for PSA in the presence of bovine serum albumin, glucose and L-cysteine. The aptasensor showed good stability, reproducibility and repeatability, deeming it a promising early detection device for prostate cancer.
- Full Text:
- Date Issued: 2021
Solvent effect on the third-order nonlinear optical properties of α-and β-tertbutyl phenoxy-substituted tin (IV) chloride phthalocyanines
- Louzada, Marcel, Britton, Jonathan, Nyokong, Tebello, Khene, Samson M
- Authors: Louzada, Marcel , Britton, Jonathan , Nyokong, Tebello , Khene, Samson M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188910 , vital:44797 , xlink:href="https://doi.org/10.1021/acs.jpca.7b07349"
- Description: This paper investigates the third-order nonlinear optical properties of 4α-(4-tert-butylphenoxy) phthalocyaninato dichlorotin(IV) (α-SnOtBpPc) and 4β-(4-tert-butylphenoxy) phthalocyaninato dichlorotin(IV) (β-SnOtBpPc) in different organic solvents. The third-order susceptibilities of α-SnOtBpPc and βSnOtBpPc are reported in different solvents, using Z-scan techniques with 10 ns laser pulses at 532 nm. Their nonlinear absorption coefficient and absorption cross sections were also determined. The molecular imaginary components of the secondorder hyperpolarizability Im[γ] of α-SnOtBpPc and β-SnOtBpPc were found to be 2.60 × 10−31 and 2.94 × 10−31 esu (tetrahydrofuran), 2.12 × 10−31 and 2.54 × 10−31 esu (chloroform), 3.06 × 10−31 and 2.54 × 10−31 esu (dichloromethane), and 1.27 × 10−31 and 1.50 × 10−31 esu (toluene), respectively. This study found that substitution at the α position has an effect of lowering the two-photon (2PA) cross section value for α-SnOtBpPc compared to that for β-SnOtBpPc, with values of 64.30 and 456.65 GM, respectively. The large 2PA cross section observed in β-SnOtBpPc is attributed to the decreased energy difference between the virtual state and the LUMO.
- Full Text:
- Date Issued: 2017
- Authors: Louzada, Marcel , Britton, Jonathan , Nyokong, Tebello , Khene, Samson M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188910 , vital:44797 , xlink:href="https://doi.org/10.1021/acs.jpca.7b07349"
- Description: This paper investigates the third-order nonlinear optical properties of 4α-(4-tert-butylphenoxy) phthalocyaninato dichlorotin(IV) (α-SnOtBpPc) and 4β-(4-tert-butylphenoxy) phthalocyaninato dichlorotin(IV) (β-SnOtBpPc) in different organic solvents. The third-order susceptibilities of α-SnOtBpPc and βSnOtBpPc are reported in different solvents, using Z-scan techniques with 10 ns laser pulses at 532 nm. Their nonlinear absorption coefficient and absorption cross sections were also determined. The molecular imaginary components of the secondorder hyperpolarizability Im[γ] of α-SnOtBpPc and β-SnOtBpPc were found to be 2.60 × 10−31 and 2.94 × 10−31 esu (tetrahydrofuran), 2.12 × 10−31 and 2.54 × 10−31 esu (chloroform), 3.06 × 10−31 and 2.54 × 10−31 esu (dichloromethane), and 1.27 × 10−31 and 1.50 × 10−31 esu (toluene), respectively. This study found that substitution at the α position has an effect of lowering the two-photon (2PA) cross section value for α-SnOtBpPc compared to that for β-SnOtBpPc, with values of 64.30 and 456.65 GM, respectively. The large 2PA cross section observed in β-SnOtBpPc is attributed to the decreased energy difference between the virtual state and the LUMO.
- Full Text:
- Date Issued: 2017
Biosynthesis of silver nanoparticles from Acacia mearnsii De Wild stem bark and its antinociceptive properties
- Avoseh, Opeyemi N, Oyedeji, Opeoluwa O, Aremu, Olukayode, Nkeh-Chungag, Benedicta N, Songca, Sandile P, Oyedeji, Adebola Omowunmi, Mohan, Sneha, Oluwafemi, Oluwatobi S
- Authors: Avoseh, Opeyemi N , Oyedeji, Opeoluwa O , Aremu, Olukayode , Nkeh-Chungag, Benedicta N , Songca, Sandile P , Oyedeji, Adebola Omowunmi , Mohan, Sneha , Oluwafemi, Oluwatobi S
- Date: 2017
- Subjects: Metal nanoparticles , Acacia mearnsii , Nociceptive pain
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/1528 , vital:37774 , https://doi.org/10.1080/17518253.2017.1287310
- Description: The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%.
- Full Text:
- Date Issued: 2017
- Authors: Avoseh, Opeyemi N , Oyedeji, Opeoluwa O , Aremu, Olukayode , Nkeh-Chungag, Benedicta N , Songca, Sandile P , Oyedeji, Adebola Omowunmi , Mohan, Sneha , Oluwafemi, Oluwatobi S
- Date: 2017
- Subjects: Metal nanoparticles , Acacia mearnsii , Nociceptive pain
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/1528 , vital:37774 , https://doi.org/10.1080/17518253.2017.1287310
- Description: The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%.
- Full Text:
- Date Issued: 2017
Reproductive phenology of two Mimusops species in relation to climate, tree diameter and canopy position in Benin (West Africa)
- Sinasson Sanni, Giséle K, Shackleton, Charlie M, Sinsin, Brian
- Authors: Sinasson Sanni, Giséle K , Shackleton, Charlie M , Sinsin, Brian
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180337 , vital:43354 , xlink:href=" https://doi.org/10.1111/aje.12457"
- Description: Assessing species phenology provides useful understanding about their autecology, to contribute to management strategies. We monitored reproductive phenology of Mimusops andongensis and Mimusops kummel, and its relationship with climate, tree diameter and canopy position. We sampled trees in six diameter classes and noted their canopy position. For both species flowering began in the dry season through to the rainy season, but peaked in the dry season, whilst fruiting occurred in the rainy season and peaked during the most humid period. Flowering was positively correlated with temperature. Conversely, fruiting was negatively correlated with temperature and positively with rainfall, only in the Guineo-Sudanian zone. For M. andongensis, flowering and fruiting prevalences were positively linked to stem diameter, while only flowering was significantly related to canopy position. For M. kummel, the relationship with stem diameter was significant for flowering prevalence only and in the Guineo-Sudanian zone. Results suggest that phylogenetic membership is an important factor restricting Mimusops species phenology. Flowering and fruiting of both species are influenced by climate, and consequently climate change might shift their phenological patterns. Long-term investigations, considering flowering and fruiting abortion, will help to better understand the species phenology and perhaps predict demographic dynamics.
- Full Text:
- Date Issued: 2018
- Authors: Sinasson Sanni, Giséle K , Shackleton, Charlie M , Sinsin, Brian
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180337 , vital:43354 , xlink:href=" https://doi.org/10.1111/aje.12457"
- Description: Assessing species phenology provides useful understanding about their autecology, to contribute to management strategies. We monitored reproductive phenology of Mimusops andongensis and Mimusops kummel, and its relationship with climate, tree diameter and canopy position. We sampled trees in six diameter classes and noted their canopy position. For both species flowering began in the dry season through to the rainy season, but peaked in the dry season, whilst fruiting occurred in the rainy season and peaked during the most humid period. Flowering was positively correlated with temperature. Conversely, fruiting was negatively correlated with temperature and positively with rainfall, only in the Guineo-Sudanian zone. For M. andongensis, flowering and fruiting prevalences were positively linked to stem diameter, while only flowering was significantly related to canopy position. For M. kummel, the relationship with stem diameter was significant for flowering prevalence only and in the Guineo-Sudanian zone. Results suggest that phylogenetic membership is an important factor restricting Mimusops species phenology. Flowering and fruiting of both species are influenced by climate, and consequently climate change might shift their phenological patterns. Long-term investigations, considering flowering and fruiting abortion, will help to better understand the species phenology and perhaps predict demographic dynamics.
- Full Text:
- Date Issued: 2018
Exploring group solidarity for insights into qualities of T-learning
- Mudokwani, Kuda, Mukute, Mutizwa
- Authors: Mudokwani, Kuda , Mukute, Mutizwa
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/390612 , vital:68568 , xlink:href="https://doi.org/10.3390/su11236825"
- Description: Across the world, organised groups of farmers participating in just and sustainability transformations encounter multiple obstacles. Through solidarity manifested in iterative processes of questioning, co-learning, collective action and reflection, and value creation for themselves and for others, some succeed in overcoming them. This article investigates how a district organic farmer association in Zimbabwe is encountering and handling group solidarity challenges arising from shifting from local to district level coordinated organic production and marketing. Based on the use of change laboratory, this paper explores solidarity at the local niche and networked district level to seek insights into the qualities of T-learning.
- Full Text:
- Date Issued: 2019
- Authors: Mudokwani, Kuda , Mukute, Mutizwa
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/390612 , vital:68568 , xlink:href="https://doi.org/10.3390/su11236825"
- Description: Across the world, organised groups of farmers participating in just and sustainability transformations encounter multiple obstacles. Through solidarity manifested in iterative processes of questioning, co-learning, collective action and reflection, and value creation for themselves and for others, some succeed in overcoming them. This article investigates how a district organic farmer association in Zimbabwe is encountering and handling group solidarity challenges arising from shifting from local to district level coordinated organic production and marketing. Based on the use of change laboratory, this paper explores solidarity at the local niche and networked district level to seek insights into the qualities of T-learning.
- Full Text:
- Date Issued: 2019
Nonlinear optical behavior of neodymium mono-and bi-nuclear phthalocyanines linked to zinc oxide nanoparticles and incorporated into poly acrylic acid
- Sekhosana, Kutloana E, Amuhaya, Edith, Nyokong, Tebello
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188766 , vital:44783 , xlink:href="https://doi.org/10.1016/j.poly.2015.12.045"
- Description: Syntheses of bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24))-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) and 2(3), 9(10), 16(17), 23(24)-(tetrapyridin-3-yloxy phthalocyaninato) neodymium (III) acetate (4) as well as their conjugates with ZnO nanoparticles (conjugates 6, 7 and 8) are presented. Thin films of conjugate 6 (where complex 3 is linked to ZnO nanoparticles via an amide bond) gave the best third-order susceptibility (5.89 × 10−8 esu), second-order hyperpolarizability (2.53 × 10−25 esu) and the lowest limiting threshold values (0.12 J cm−2). The nonlinear behavior is enhanced in solid state when compared to solution.
- Full Text:
- Date Issued: 2016
- Authors: Sekhosana, Kutloana E , Amuhaya, Edith , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188766 , vital:44783 , xlink:href="https://doi.org/10.1016/j.poly.2015.12.045"
- Description: Syntheses of bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24))-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) and 2(3), 9(10), 16(17), 23(24)-(tetrapyridin-3-yloxy phthalocyaninato) neodymium (III) acetate (4) as well as their conjugates with ZnO nanoparticles (conjugates 6, 7 and 8) are presented. Thin films of conjugate 6 (where complex 3 is linked to ZnO nanoparticles via an amide bond) gave the best third-order susceptibility (5.89 × 10−8 esu), second-order hyperpolarizability (2.53 × 10−25 esu) and the lowest limiting threshold values (0.12 J cm−2). The nonlinear behavior is enhanced in solid state when compared to solution.
- Full Text:
- Date Issued: 2016
Monitoring and Management Mechanisms on Stress in HEI in Eastern Cape Province in South Africa: Critical Review
- Asoba, Samson Nambei, Patricia, Nteboheng Mefi
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Teachers--Job stress , Ill-Discipline of Learners , Middle school education -- Parent participation
- Language: English
- Type: text , article , Article
- Identifier: http://hdl.handle.net/11260/8068 , vital:61393 , xlink:href="https://www.abacademies.org/articles/monitoring-and-management-mechanisms-on-stress-in-hei-in-eastern-cape-province-in-south-africa-critical-review-10636.html"
- Description: Stress is a global phenomenon that affects everyone regardless of gender, resources and environment. Although this phenomenon is well researched, teachers’ experiences of stress remains a worrying challenge particularly to schools’ effectiveness. This study sought to establish how monitoring and management mechanism that can assist teachers to cope with stress challenges. These are some of the recommendation: that the school disciplinary committee should be trained in various disciplinary measures that may be implemented in the school to curb learner ill-discipline and lack of commitment, that working relationship should be built between schools and the Department of Basic Education, motivational speakers and educational counsellors should meet with all learners on a regular basis to motivate them to have high desire for and interest in education and to build their self-confidence in the classroom, providing all the schools with healthy environment in classrooms, provision of learning and teaching materials to all schools, schools should set up an effective school-parents partnership in order to promote a safe drug and alcohol free environment, employ enough teachers in all secondary schools and the Department of Basic Education at district level should make room for stress management workshops for teachers.
- Full Text:
- Date Issued: 2021
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Teachers--Job stress , Ill-Discipline of Learners , Middle school education -- Parent participation
- Language: English
- Type: text , article , Article
- Identifier: http://hdl.handle.net/11260/8068 , vital:61393 , xlink:href="https://www.abacademies.org/articles/monitoring-and-management-mechanisms-on-stress-in-hei-in-eastern-cape-province-in-south-africa-critical-review-10636.html"
- Description: Stress is a global phenomenon that affects everyone regardless of gender, resources and environment. Although this phenomenon is well researched, teachers’ experiences of stress remains a worrying challenge particularly to schools’ effectiveness. This study sought to establish how monitoring and management mechanism that can assist teachers to cope with stress challenges. These are some of the recommendation: that the school disciplinary committee should be trained in various disciplinary measures that may be implemented in the school to curb learner ill-discipline and lack of commitment, that working relationship should be built between schools and the Department of Basic Education, motivational speakers and educational counsellors should meet with all learners on a regular basis to motivate them to have high desire for and interest in education and to build their self-confidence in the classroom, providing all the schools with healthy environment in classrooms, provision of learning and teaching materials to all schools, schools should set up an effective school-parents partnership in order to promote a safe drug and alcohol free environment, employ enough teachers in all secondary schools and the Department of Basic Education at district level should make room for stress management workshops for teachers.
- Full Text:
- Date Issued: 2021
Woody plant species richness, composition and structure in urban sacred sites, Grahamstown, South Africa
- De Lacy, Peter J G, Shackleton, Charlie M
- Authors: De Lacy, Peter J G , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180079 , vital:43307 , xlink:href="https://doi.org/10.1007/s11252-017-0669-y"
- Description: Sacred sites are important not only for their traditional, spiritual or religious significance, but may also potentially be valuable for biodiversity conservation in human transformed landscapes. Yet, there has been little consideration of sacred sites in urban areas in this respect. Consequently, to better understand the ecosystem service and conservation value of urban sacred sites, inventories of their floral communities are needed. We examined the richness, composition and structure of the trees and shrubs in 35 urban churchyards and cemeteries in the City of Saints (Grahamstown). The combined area of urban sacred sites (38.7 ha) represented 2.2% of the city area and 13.6% of the public green space area. Species richness of woody plants was high, albeit dominated by non-native species. Levels of similarity among sites were low, indicating the effects of individual management regimens. There was no relationship between age of the site and measured attributes of the vegetation, nor were there any significant differences in vegetation among different religious denominations. However, the basal area and number of woody plants was significantly related to site size. These results indicate the significant heterogeneity of urban sacred sites as green spaces within the urban matrix. The significance of this heterogeneity in providing ecosystem services to users of sacred sites and the broader urban communities requires further investigation.
- Full Text:
- Date Issued: 2017
- Authors: De Lacy, Peter J G , Shackleton, Charlie M
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180079 , vital:43307 , xlink:href="https://doi.org/10.1007/s11252-017-0669-y"
- Description: Sacred sites are important not only for their traditional, spiritual or religious significance, but may also potentially be valuable for biodiversity conservation in human transformed landscapes. Yet, there has been little consideration of sacred sites in urban areas in this respect. Consequently, to better understand the ecosystem service and conservation value of urban sacred sites, inventories of their floral communities are needed. We examined the richness, composition and structure of the trees and shrubs in 35 urban churchyards and cemeteries in the City of Saints (Grahamstown). The combined area of urban sacred sites (38.7 ha) represented 2.2% of the city area and 13.6% of the public green space area. Species richness of woody plants was high, albeit dominated by non-native species. Levels of similarity among sites were low, indicating the effects of individual management regimens. There was no relationship between age of the site and measured attributes of the vegetation, nor were there any significant differences in vegetation among different religious denominations. However, the basal area and number of woody plants was significantly related to site size. These results indicate the significant heterogeneity of urban sacred sites as green spaces within the urban matrix. The significance of this heterogeneity in providing ecosystem services to users of sacred sites and the broader urban communities requires further investigation.
- Full Text:
- Date Issued: 2017