title: An Investigation of Malaysian Secondary School Students’ Mental Models of Acid-Base Chemistry

authors: Cyril, Nelson

abstract: There are many studies in chemistry investigating students’ difficulties in understanding chemical bonding, particle nature of matter and others, but relatively few on acid-base chemistry. One approach for reducing students’ learning difficulties uses model-based science teaching, which involves models and mental models.
This thesis study investigates students’ mental models in acid-base chemistry concepts to give insights into Malaysian secondary students’ thinking in acid-base chemistry. In addition, teachers’ mental models and the curricular models were also examined in order to explore the degree of alignment between the three models. At Forms 2, 4, and 6 levels of Malaysian schooling eight secondary school students and two teachers were interviewed at each level in an effort to examine their mental models using the Interview-About-Concepts and Interview- About-Instances data gathering methods. In addition, Forms 2, 4 and 6 curricular models (i.e., curriculum documents) were examined to obtain insights into the curricular models.
The area under investigation for this thesis study involves six selected acid-base chemistry concepts and their links to four acid-base models. The six selected acid-base chemistry concepts are Macroscopic Properties, Neutralisation, Acid-Strength, Acid-Base Equilibrium, Buffers, and Acid-Base Electron Pair Bonding while the four acid-base models are the Phenomenological, Arrhenius, Brønsted-Lowry, and Lewis models.
To determine the nature of students’ mental models, attributes of these models were identified and gathered from students’ expressed models, that is their responses to probe questions about the selected acid-base concepts and compared with the attributes of each scientific acid-base models. This comparison provided evidence of students’ use/non-use of the attributes of the appropriate acid-base models to explain six selected acid-base chemistry concepts. Next, a mental model framework was developed and used to classify students’ attributes into Stage 1, Stage 2, and Stage 3 mental models. The Stage 1 mental model was developed based on the Macroscopic Properties acid-base chemistry concept to indicate students’ use or non–use of the Phenomenological model. The Stage 2 mental model was developed to determine students’ use or non-use of the Arrhenius model to explain the Neutralisation and Acid-Strength concepts. The Stage 3 mental model comprising the Acid-Base Equilibrium, Buffers, and Acid-Base Electron Pair Bonding concepts were investigated to identify students’ use or non-use of the Brønsted-Lowry and the Lewis model.
Also, under investigation was a comparison of students’ mental models with teachers’ mental models and the curricular model. At Form 6 schooling level the students’ mental models demonstrated complete dissonance with the teachers’ mental models and the curricular models. The causes for this dissonance may be the lack of specificity in the Malaysian curriculum, students’ limited cognitive ability in terms of age-approriate concepts, and insufficient teachers’ pedagogical knowledge. 
From the findings of this thesis study, it is recommended that the Lewis acid-base model, be omitted from the Form 6 Malaysian curriculum because students’ were not able to understand Acid-Base Electron Pair Bonding chemistry concept. Also, for other acid-base chemistry concepts, Malaysian teachers are encouraged to use student-centred teaching methods utilizing acid-base models to help improve their students’ understanding.

text: An Investigation of Malaysian Secondary School Students’ Mental Models of Acid-Base Chemistry There are many studies in chemistry investigating students’ difficulties in understanding chemical bonding, particle nature of matter and others, but relatively few on acid-base chemistry. One approach for reducing students’ learning difficulties uses model-based science teaching, which involves models and mental models.
This thesis study investigates students’ mental models in acid-base chemistry concepts to give insights into Malaysian secondary students’ thinking in acid-base chemistry. In addition, teachers’ mental models and the curricular models were also examined in order to explore the degree of alignment between the three models. At Forms 2, 4, and 6 levels of Malaysian schooling eight secondary school students and two teachers were interviewed at each level in an effort to examine their mental models using the Interview-About-Concepts and Interview- About-Instances data gathering methods. In addition, Forms 2, 4 and 6 curricular models (i.e., curriculum documents) were examined to obtain insights into the curricular models.
The area under investigation for this thesis study involves six selected acid-base chemistry concepts and their links to four acid-base models. The six selected acid-base chemistry concepts are Macroscopic Properties, Neutralisation, Acid-Strength, Acid-Base Equilibrium, Buffers, and Acid-Base Electron Pair Bonding while the four acid-base models are the Phenomenological, Arrhenius, Brønsted-Lowry, and Lewis models.
To determine the nature of students’ mental models, attributes of these models were identified and gathered from students’ expressed models, that is their responses to probe questions about the selected acid-base concepts and compared with the attributes of each scientific acid-base models. This comparison provided evidence of students’ use/non-use of the attributes of the appropriate acid-base models to explain six selected acid-base chemistry concepts. Next, a mental model framework was developed and used to classify students’ attributes into Stage 1, Stage 2, and Stage 3 mental models. The Stage 1 mental model was developed based on the Macroscopic Properties acid-base chemistry concept to indicate students’ use or non–use of the Phenomenological model. The Stage 2 mental model was developed to determine students’ use or non-use of the Arrhenius model to explain the Neutralisation and Acid-Strength concepts. The Stage 3 mental model comprising the Acid-Base Equilibrium, Buffers, and Acid-Base Electron Pair Bonding concepts were investigated to identify students’ use or non-use of the Brønsted-Lowry and the Lewis model.
Also, under investigation was a comparison of students’ mental models with teachers’ mental models and the curricular model. At Form 6 schooling level the students’ mental models demonstrated complete dissonance with the teachers’ mental models and the curricular models. The causes for this dissonance may be the lack of specificity in the Malaysian curriculum, students’ limited cognitive ability in terms of age-approriate concepts, and insufficient teachers’ pedagogical knowledge. 
From the findings of this thesis study, it is recommended that the Lewis acid-base model, be omitted from the Form 6 Malaysian curriculum because students’ were not able to understand Acid-Base Electron Pair Bonding chemistry concept. Also, for other acid-base chemistry concepts, Malaysian teachers are encouraged to use student-centred teaching methods utilizing acid-base models to help improve their students’ understanding.

year: 2015

title: Fungal metabolite chemistry: Sporidesmin, crepidotine

authors: Ronaldson, John William

abstract: This thesis was concerned with the chemistry of two fungal products, sporidesmin and crepidotine. The structure of sporidesmin was known but aspects of its chemistry, such as how it could be modified to function as an antigen, were not. The structure of crepidotine was unknown but was elucidated in the course of this work.
Since only 50 mg of crepidotine was available, non-destructive methods were used to arrive at the structure, 2-phenyl-1,6-naphthyridin-4-one. Of these methods, ¹H nuclear magnetic resonance spectroscopy was the most important. This spectrum (¹H n.m.r.) of crepidotine was compared with known or expected spectra of possible isomers most of which were unknown.
Sporidesmin is the toxin which causes Facial Eczema. One approach for combating the problem of Facial Eczema is to develop antibodies in the animals against sporidesmin. Sporidesmin is too small a molecule per se to induce antibody formation so one of the aims of this thesis was to produce derivatives of sporidesmin and to complex them to proteins. Proteins with many molecules of sporidesmin covalently bound to them were produced to be used as antigens. When animals were treated with these antigens, antibodies were detected in their sera. The titre was low for sporidesmin complexed to albumins but four times higher when sporidesmin was complexed to bovine thyroglobulin. 
The method of complexing sporidesmin to the proteins was to open the -S-S- bridge (in sporidesmin) and alkylate the sulphur atoms with iodoacetic esters. When protein was treated with these sporidesmin derivatives the ε-amino-groups of the lysyl residues (in the protein) were transacylated yielding modified sporidesmin covalently bound to the protein, synthetic or natural.
The new compounds formed from sporidesmin in these syntheses were: diethyl and dimethyl secosporidesmin-S,S'-diacetate, ethyl and methyl 11a-mercaptosecosporidesmin-3-S-acetate, methyl 3-mercaptosecosporidesmin-11a-S-acetate; and one of the antigens was cross-linked poly(ethoxy)-poly(secosporidesmin-S,S'-diacetyl)poly-(L-lysine). Of other new derivatives of sporidesmin that were synthesized, 3,11a-dimercaptosecosporidesmin, S,S'-homosporidesmin, and sporidesmin 11-(methyl glutarate), the first was the most difficult to prepare. When attempted in the normal way (opening the -S-S- bridge as for the above esters) only sporidesmin was recovered. But the dimercapto-compound was obtained when oxygen was eliminated in the reaction. 
Because the toxicity of the sporidesmin molecule resides in the epidithiodioxopiperazine ring, means of covalently linking sporidesmin to protein without altering the -S-S- bridge were sought, e.g. acylation or diazonium coupling with suitable bridging groups. Having successfully acylated with the chloroacetyl group (forming sporidesmin di(chloroacetate) it may be possible to complex this ester to protein through the halogen atom.
In the diazonium coupling reaction, the sole aromatic hydrogen resisted coupling. Diazonium salts eliminated the epidithiodioxopiperazine ring by rupturing the pyrrolidine ring: the products were the strongly coloured substituted indoleazobenzenes, 5-chloro-2-hydroxy-6,7- dimethoxy-1-methyl-4'-nitroindole-3-azobenzene and the 2'-chloro- and 2'-nitro-analogues. From anhydrodethiosporidesmin 5-chloro-6,7-dimethoxy-8-methyl-2' ,4'-dinitropyrrolo[2,3-b]indole-2-azobenzene was obtained. These indoleazobenzenes are new compounds.
In the search for methods of diazonium coupling to o-dihydroxy-benzene, veratrole, the following new compounds were synthesized: 2-chloro-3', 4'-dimethoxy-4-nitrobiphenyl, 2-chloro-4'-hydroxy-3'-methoxy-4-nitroazobenzene, 4'-hydroxy-3'-methoxy-2, 4-dinitroazobenzene, 3', 4'-dimethoxy-2,4-dinitroazobenzene, 2-chloro-3', 4'-dimethoxy-4-nitroazobenzene and 2-chloro-4, 5-dimethoxy-2', 4'-dinitroazobenzene. 
In the ¹³C nuclear magnetic resonance spectra of sporidesmin and sporidesmin-D (dimethylthiosecosporidesmin) (decoupled and undecoupled) the peaks were assigned to the appropriate carbons. Where a resonance seemed anomalous, a reasonable explanation of the anomaly has been put forward. Comparison of the spectra of the two compounds indicated the resonances of those carbons which were involved in the strained epidithiodioxopiperazine ring system. Having assigned the peaks for sporidesmin, the structure of unknown analogues may now be more readily elucidated. 
An analogue of sporidesmin, sporidesmin-E, of comparable toxicity, having an -S-S-S- bridge was synthesized from sporidesmin for field studies. It was an unstable molecule readily decomposing to sporidesmin plus sulphur, e.g. pure sporidesmin-E always showed three spots in thin layer chromatography. The mixed melting point between these two compounds was undepressed (they melted within 3.5° of each other). That sporidesmin-E had been formed was confirmed by the M⁺ being 32 mass units greater than sporidesmin but this was still no criterion of purity. In the hydrogen-bonding investigation of the two compounds sporidesmin absorbed in the νOH region where sporidesmin-E did not so the degree that sporidesmin-E was contaminated with sporidesmin could be determined. Comparison of the infra-red spectra of sporidesmin and sporidesmin-E prepared in different ways (in KBr from MeOH or EtOEt, in nujol or in halocarbon oil) showed there were only minor differences between them. 
The hydrogen bonding analysis revealed that the C-S bonds of 3,11a-di-mercaptosecosporidesmin and sporidesmin-E were similarly orientated (i.e. diverging) and not more or less parallel as in sporidesmin-D. The mono-mercapto-derivative (methyl 11a-mercaptosecosporidesmin-3-S-acetate) showed no νSH peak: the elements of the thiol group are present (m.s.) but the hydrogen is ionic and with the adjacent amido-group is apparently in hyperconjugation.

text: Fungal metabolite chemistry: Sporidesmin, crepidotine This thesis was concerned with the chemistry of two fungal products, sporidesmin and crepidotine. The structure of sporidesmin was known but aspects of its chemistry, such as how it could be modified to function as an antigen, were not. The structure of crepidotine was unknown but was elucidated in the course of this work.
Since only 50 mg of crepidotine was available, non-destructive methods were used to arrive at the structure, 2-phenyl-1,6-naphthyridin-4-one. Of these methods, ¹H nuclear magnetic resonance spectroscopy was the most important. This spectrum (¹H n.m.r.) of crepidotine was compared with known or expected spectra of possible isomers most of which were unknown.
Sporidesmin is the toxin which causes Facial Eczema. One approach for combating the problem of Facial Eczema is to develop antibodies in the animals against sporidesmin. Sporidesmin is too small a molecule per se to induce antibody formation so one of the aims of this thesis was to produce derivatives of sporidesmin and to complex them to proteins. Proteins with many molecules of sporidesmin covalently bound to them were produced to be used as antigens. When animals were treated with these antigens, antibodies were detected in their sera. The titre was low for sporidesmin complexed to albumins but four times higher when sporidesmin was complexed to bovine thyroglobulin. 
The method of complexing sporidesmin to the proteins was to open the -S-S- bridge (in sporidesmin) and alkylate the sulphur atoms with iodoacetic esters. When protein was treated with these sporidesmin derivatives the ε-amino-groups of the lysyl residues (in the protein) were transacylated yielding modified sporidesmin covalently bound to the protein, synthetic or natural.
The new compounds formed from sporidesmin in these syntheses were: diethyl and dimethyl secosporidesmin-S,S'-diacetate, ethyl and methyl 11a-mercaptosecosporidesmin-3-S-acetate, methyl 3-mercaptosecosporidesmin-11a-S-acetate; and one of the antigens was cross-linked poly(ethoxy)-poly(secosporidesmin-S,S'-diacetyl)poly-(L-lysine). Of other new derivatives of sporidesmin that were synthesized, 3,11a-dimercaptosecosporidesmin, S,S'-homosporidesmin, and sporidesmin 11-(methyl glutarate), the first was the most difficult to prepare. When attempted in the normal way (opening the -S-S- bridge as for the above esters) only sporidesmin was recovered. But the dimercapto-compound was obtained when oxygen was eliminated in the reaction. 
Because the toxicity of the sporidesmin molecule resides in the epidithiodioxopiperazine ring, means of covalently linking sporidesmin to protein without altering the -S-S- bridge were sought, e.g. acylation or diazonium coupling with suitable bridging groups. Having successfully acylated with the chloroacetyl group (forming sporidesmin di(chloroacetate) it may be possible to complex this ester to protein through the halogen atom.
In the diazonium coupling reaction, the sole aromatic hydrogen resisted coupling. Diazonium salts eliminated the epidithiodioxopiperazine ring by rupturing the pyrrolidine ring: the products were the strongly coloured substituted indoleazobenzenes, 5-chloro-2-hydroxy-6,7- dimethoxy-1-methyl-4'-nitroindole-3-azobenzene and the 2'-chloro- and 2'-nitro-analogues. From anhydrodethiosporidesmin 5-chloro-6,7-dimethoxy-8-methyl-2' ,4'-dinitropyrrolo[2,3-b]indole-2-azobenzene was obtained. These indoleazobenzenes are new compounds.
In the search for methods of diazonium coupling to o-dihydroxy-benzene, veratrole, the following new compounds were synthesized: 2-chloro-3', 4'-dimethoxy-4-nitrobiphenyl, 2-chloro-4'-hydroxy-3'-methoxy-4-nitroazobenzene, 4'-hydroxy-3'-methoxy-2, 4-dinitroazobenzene, 3', 4'-dimethoxy-2,4-dinitroazobenzene, 2-chloro-3', 4'-dimethoxy-4-nitroazobenzene and 2-chloro-4, 5-dimethoxy-2', 4'-dinitroazobenzene. 
In the ¹³C nuclear magnetic resonance spectra of sporidesmin and sporidesmin-D (dimethylthiosecosporidesmin) (decoupled and undecoupled) the peaks were assigned to the appropriate carbons. Where a resonance seemed anomalous, a reasonable explanation of the anomaly has been put forward. Comparison of the spectra of the two compounds indicated the resonances of those carbons which were involved in the strained epidithiodioxopiperazine ring system. Having assigned the peaks for sporidesmin, the structure of unknown analogues may now be more readily elucidated. 
An analogue of sporidesmin, sporidesmin-E, of comparable toxicity, having an -S-S-S- bridge was synthesized from sporidesmin for field studies. It was an unstable molecule readily decomposing to sporidesmin plus sulphur, e.g. pure sporidesmin-E always showed three spots in thin layer chromatography. The mixed melting point between these two compounds was undepressed (they melted within 3.5° of each other). That sporidesmin-E had been formed was confirmed by the M⁺ being 32 mass units greater than sporidesmin but this was still no criterion of purity. In the hydrogen-bonding investigation of the two compounds sporidesmin absorbed in the νOH region where sporidesmin-E did not so the degree that sporidesmin-E was contaminated with sporidesmin could be determined. Comparison of the infra-red spectra of sporidesmin and sporidesmin-E prepared in different ways (in KBr from MeOH or EtOEt, in nujol or in halocarbon oil) showed there were only minor differences between them. 
The hydrogen bonding analysis revealed that the C-S bonds of 3,11a-di-mercaptosecosporidesmin and sporidesmin-E were similarly orientated (i.e. diverging) and not more or less parallel as in sporidesmin-D. The mono-mercapto-derivative (methyl 11a-mercaptosecosporidesmin-3-S-acetate) showed no νSH peak: the elements of the thiol group are present (m.s.) but the hydrogen is ionic and with the adjacent amido-group is apparently in hyperconjugation.

year: 1978

title: Interpreting & practicing kaupapa Māori research in a community setting: The in’s and out’s

authors: Thompson, Keri

subjects: Māori

abstract: Pou Tuia Rangahau is a unique community based research unit based within a kaupapa Māori organisation. Kaupapa Māori methodologies are utilised, with the importance of these methodologies being that Māori are defining the process, doing the research for and about Māori, with the eventual outcome being meaningful to Māori. This paper is placed within this wider context of Kaupapa Māori and how it applies to the practice of research in particular. We discuss how we interpret and practice Kaupapa Māori Research (KMR) within an urban community based organisation by highlighting a particular piece of research that was undertaken by Pou Tuia Rangahau, the Research Unit of Te Runanga O Kirikiriroa Trust Inc.

text: Interpreting & practicing kaupapa Māori research in a community setting: The in’s and out’s Pou Tuia Rangahau is a unique community based research unit based within a kaupapa Māori organisation. Kaupapa Māori methodologies are utilised, with the importance of these methodologies being that Māori are defining the process, doing the research for and about Māori, with the eventual outcome being meaningful to Māori. This paper is placed within this wider context of Kaupapa Māori and how it applies to the practice of research in particular. We discuss how we interpret and practice Kaupapa Māori Research (KMR) within an urban community based organisation by highlighting a particular piece of research that was undertaken by Pou Tuia Rangahau, the Research Unit of Te Runanga O Kirikiriroa Trust Inc.

year: 2008