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Item Misconceptions in chemistry : a comparative study of Samoa and New Zealand high schools to identify their different origins and approaches to eliminate and correct them : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Education at Massey University, Palmerston North, New Zealand(Massey University, 2011) Suaalii, FagueleThe report describes a comparative study of students' misconceptions. It does so by investigating year 13 students' conceptual understanding of the structure bonding and related properties of diamond and graphite. The aims of the case study are to elicit, identify, and compare the different origins and develop appropriate strategies to promote correct conceptual understanding of chemistry concepts. The study involved sixty students, and three chemistry teachers from two different schools; one from Palmerston North, New Zealand and the other from Apia, Samoa. Open-ended question strategy was used to elicit the students' misconceptions, followed by interview and classroom observations of a sample of students. Analyses of the responses to the open question, interviews, students' artifacts and classroom observations, revealed the origins of the students' misconceptions about the structure, bonding and related properties of diamond and graphite.Item Improving teaching and learning for chemical equilibrium and acids and bases in Year 12 chemistry : a thesis submitted in partial fulfilment of the requirements for the degree of MAster of Education at Massey University, Palmerston North, New Zealand(Massey University, 2005) Downs, Lauren MThe aims of this action research study were to develop, implement, and test the efficacy of four strategies designed to improve the teaching and learning of chemical equilibrium and acids and bases in year 12 chemistry. The study took place in a New Zealand secondary school, with two year 12 chemistry teachers and fifteen randomly selected students taking part. Semi-structured interviews used to elicit students' pre-teaching mental models of concepts within chemical equilibrium and acids and bases revealed a range of misconceptions and a limited ability to represent the sub-microscopic level of chemistry concepts. Teachers then used information from the interviews to inform the planning of lessons for each topic. The new teaching strategies employed by the teachers centred around Johnstone's three levels of chemistry; using a macroscopic, sub-microscopic, symbolic sequence during teacher explanations of concepts. Particular emphasis was placed on modelling the sub-microscopic level of each concept with magnetic cardboard dots and student role plays. The action research process allows teachers to improve their own understandings and teaching practices through cycles of planning, action, observation and reflection. Although the action research methodology used here was new to both teachers at the start of the study, it provided a useful structure in which to trial the new strategies. Reflection in action research is an opportunity for teachers to reflect on, and evaluate, the effects of their action. This study demonstrates that understanding of concepts within chemical equilibrium and acids and bases is significantly improved if the sub-microscopic level of concepts is represented. For the students in this study, the preferred method of representing the sub-microscopic level was with cardboard dots rather than student role plays. Ideally, students themselves need to practise representing the sub-microscopic level with cardboard dots or other concrete models if they are to gain better understanding of the sub-microscopic level.Item Towards an understanding of the way chemistry students relate to teaching software, using stereochemistry as the vehicle : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy(Massey University, 2002) Pavlinic, SlavicaThe aim of the project was to identify features crucial for the effective software-based learning of chemistry. The project involved four connected studies using two methods: one developed for evaluation of student-software interaction (videotaping and stimulated recall interviewing); the other, phenomenography for investigating student conceptions related to their understanding of stereochemistry, a concept addressed by the developed tutorial. The main insights fall into two categories: the development of chemistry educational software and teaching and learning of chemistry specifically the concepts of stereochemistry. The original stereochemistry tutorial employed multiple representations, free navigation and model progression. Students' ideas were used to modify the tutorial. This resulted in the learning tasks covering the properties of enantiomers, using the animation and guided discovery. The use of computers in chemistry has two advantages over the traditional educational tools. Using 3D interactive ball and stick models helped students to visualise molecules and animation assisted to visualise aspects (properties), which are impossible to observe under laboratory conditions. Learning chemistry is strongly influenced by the way chemistry is taught. Students experienced chemistry in two worlds separated from one another - the world of body of chemistry knowledge and the world of real substances (dream world-real world concept). This insight contributes to an understanding of how learning chemistry takes place.Item Synthesis, structure and reactivity of the later transition metal complexes containing a multidentate phosphorus-nitrogen hybrid ligand : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University(Massey University, 2000) Kennedy, Steven Michael FornaraChapter 1 - This first part of the chapter aims to give the reader a flavour of the chemistry concerning phosphorus-nitrogen hybrid ligands containing both phosphorus and nitrogen donor atoms. This will be achieved by highlighting selected relevant examples from the literature. The second part will introduce the ligand 2-(diphenylphosphino)-N-[2-(diphenylphoshino)benzylidene]benzeneamine, (PNCHP), which is the subject of Chapters 2 through 6. Chapter 2 - The ligand PNCHP reacts with [Mo(CO)3(1,3,5-cycloheptatriene)] to give the complex fac-[Mo(CO)3(PNCHP-K3 P,N,P)] which readily isomerises to mer-[Mo(CO)3(PNCHP-K3P,N,P)]. Kinetic studies on the isomerisation in acetone yielded the first-order forward rate constants (k1) 1.22x10 -5, 4.18x10 -5, 1.72X10 -4 and 4.89x10 -4 s-1 at 19.5, 29.7, 40.0 and 49.5 °C respectively, with thermodynamic activation parameters ΔH 1‡ and ΔS1‡ of 95 kJ mol-1 and -14.1 J mol-1 K-1 respectively. The related complex fac-[Mo(CO)3(PNHCH2P-K3P,N,P)] (PNHCH2P = 2-(diphenylphosphino)-N-[(2-diphenylphosphino)benzyl]benzeneamine does not undergo isomerisation. The complex cis-[Cr(CO)4(PNCHP-K2N,P)] reacts with sulfur to give cis-[Cr(CO)4(SPNCHP-K2N,P)] and reacts with methyliodide under an atmosphere of carbon monoxide to yield the anion [Cr(CO)5I]-. Chapter 3 - The complexes [M(CO)3(PNCHP-K3P,N,P)] (M = Cr, Mo or W), containing a terdentate PNCHP ligand, react with H+ to give the protonated products [M(CO)3{PN(H)CHP-k2P,P-η2(C=N)}]+, where the imino group has 'slipped' from a K1N to a η2(C=N) coordination mode as a result of the protonation of the nitrogen atom. When the acid is HC1 the above cation [M(CO)3{PN(H)CHP-K2P,P-η2(C=N)}]+ (M = Mo or W) converts to cis-[M(CO)2C12(PNHCH2P-K3P,N,P)]. In this unusual reaction the imine group of the PNCHP ligand has been reduced to an amine concurrently with the two electron oxidation of the metal. In contrast, on reaction of cis-[Cr(CO)4(PNCHP-K2N,P)] with H+, the bidentate PNCHP ligand dissociates from the metal resulting in cyclisation of the ligand to give a phosphonium salt. Chapter 4 - PNCHP favours terdentate coordination with Pd(II) and Pt(II). The complexes [Mcl(PNCHP-K3.P,N,P)]Cl and [Pd(CH3)(PNCHP-K3P,N,P)]Cl are synthesised starting with [MCl2(1,5-cyclooctadiene)] and [M(CH3)Cl(1,5-cyclooctadiene)], respectively. The ionic chlorides can be exchanged with BF4- using AgBF4. Abstraction of the covalent chloride with AgBF4 in the presence of acetonitrile yields [Pt(CH3CN)(PNCHP-K3P,N,P)]2+. The acetonitrile ligand of this dication can be substituted with triphenylphosphane, 2-picoline, or 3-picoline. The reaction of [Pt(CH3CN)(PNCHP-K3P,N,P)]2+. with 1,10-phenanthroline, 2,2'-bipyridine, bis(diphenylphosphino)ethane or 2,2':6',2"-terpyridine (L-L) yields complexes of the type [Pt(L-L)(PNCHP-K3P,N,P)]2+ - the first five-coordinate platinum(II) dications. Chapter 5 - The complex [RhCl(PNCHP-K3P,N,P)] is synthesised by reacting the PNCHP ligand with 0.5 equivalents of [{RhCl(1,5-cyclooctadiene)}2]. This extremely reactive compound undergoes oxidative addition of dichloromethane and chloroform to yield complexes of the type [RhCl2(R)(PNCHP-K3P,N,P)] (R = CH2Cl or CDCl2). Addition of carbon monoxide to [RhCl(PNCHP-K3P,N,P)] results in the adduct [RhCl(CO)(PNCHP-k3P,N,P)] which is in equilibrium with square planar complex [Rh(CO)(PNCHP-K3P,N,P)]Cl. The coordinated chloride ligand of [RhCl(PNCHP-K3P,N,P)] can be substituted with tetrahydrofuran, acetonitrile or triphenylphosphane. Chapter 6 - The triosmium clusters [Os3(CO)11(CH3CN)] and [Os3(CO)10(CH3CN)2] react with PNCHP to give [{Os3(CO)11}2(PNCHP-K2P,P)] (containing PNCHP bridging equatorially two osmium triangles), two coordination isomers of [Os3(CO)11(PNCHP-K1P)] and 1,1-[OS3(CO)10(PNCHP-K2P,P)], respectively. When 1,1-[Os3(CO)10(PNCHP-K2P,P)] is reacted with one equivalent of trimethylamineoxide the major product is [OS3(μ-H)(CO)7(μ3-PNCP)], in which the imine hydrogen of PNCHP has migrated to the osmium cluster and PNCP is left to act as a triply bridging nine-electron donor. Two geometrical isomers of [Os3(μ-H)(CO)8(μ2-PNCP)] are found as minor products, with PNCP acting as a doubly bridging seven-electron donor ligand.Item Synthesis of cyclodextrin composites incorporating targeting and drug carrying capabilities : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry, Massey University, Turitea Campus, Palmerston North, New Zealand(Massey University, 2010) White, Rachel JaneA selective, versatile, and robust methodology for the bi-functionalisation of - cyclodextrin has been developed which allows for the attachment of peptides and/or sulfonamides in varying C- and N-terminal combinations on resin using NFluorenylmethoxycarbonyl (Fmoc) Solid Phase Peptide Synthesis (SPPS). Mono-6Afluorenylmethyloxycarbonylamino- mono-6X-succinyl-b-cyclodextrin, an amino acid based bi-functionalised derivative of b-cyclodextrin, has been functionalised with the bioactive peptide, bradykinin, and/or sulfonamides using Fmoc SPPS on Rink resin. The all-in-one molecule contains a carrier (cyclodextrin), targeting agent (bradykinin) and/or drug (sulfonamide). Varying combinations of these bradykinin-focused molecules have been synthesised in an attempt to determine the structure-function relationship against cancer cell lines using cell-based screening in vitro. This study commenced with the synthesis of two linkers on to cyclodextrin. This enabled selective binding directly on to the resin, or a peptide attached to the resin. Peptide growth and/or cleavage from the resin followed allowing for the synthesis of peptide-cyclodextrin species in various combinations. Fmoc SPPS techniques have been employed to allow for the addition and synthetic extension of peptides on to cyclodextrin. Peptide purification was achieved by reverse phase high pressure liquid chromatography, and nuclear magnetic resonance spectroscopy and mass spectrometry were used to determine the success of the coupling reactions and identification of cyclodextrin regio isomers. Sulfonamide additions to the cyclodextrin and/or peptide compounds were obtained after numerous studies investigating the optimal reaction conditions. 4-Fluorenylmethyloxycarbonylaminobenzenesulfonyl chloride was found to give the highest yields for the synthesis of C-terminal peptide sulfonamides with 4- carboxybenzenesulfonamide giving the highest optimal yields for N-terminal peptide sulfonamides. Peptide coupling efficiency of cyclodextrin and sulfonamides were investigated and optimised by comparing different SPPS resins and solvents. The incorporation of spacers between the peptide/cyclodextrin and/or resin have also been investigated in an attempt to improve overall reaction yields. Preliminary bioassay testing against tumour cell lines HT-29 Human Duodenum, Hs700T Human pancreatic adenocarcinoma, and MA-104 Human pancreatic adenocarcinoma were performed. The MTT assay and the flow cytometry assay were used to show the effect of varying combinations of these cyclodextrin-peptidesulfonamide molecules against the three cell lines and compared to a known anticancer drug, 5-Fluorouracil. Despite employment of simple entities in the construction of these compounds, an increase in cell proliferation (ca 10-20%) was seen for some cyclodextrin-bradykinin complexes. In addition, an exposed C-terminus on the bradykinin-sulfonamide moiety and an exposed N-terminus on the cyclodextrinbradykinin sulfonamide moiety both gave positive results. Mixed results were obtained with the addition of a linker between the cyclodextrin and the bradykinin molecules (less then 5% increase or decrease) compared to their non-linker counterparts.Item "A most exquisite fellow" — William White and an Atlantic world perspective on the seventeenth-century chymical furnace(Maney Publishing, 2007) White, Bruce; Woodward, Walter W.The seventeenth-century technologist and colonist William White (ca. 1600–73) has been cited as an alchemical tutor to Gabriel Plattes and George Starkey, and hailed as an early modern “wizard of industrial efficiency.” This study — the first that focuses on White individually — pays particular attention to White’s extraordinary reputation for furnace design and manufacture. By examining the sources of knowledge and social connections that enabled White to acquire and disseminate his knowledge of metallurgy, the authors develop a genealogy of fornacic design that extends from the continent to the Atlantic world and back again, connecting White to better known figures such as Cornelis Drebbel and Robert Boyle. By foregrounding, through White, the technology of early modern alchemy, the authors also hope to emphasise the importance of practical craft in the development of the chemical arts.Item Unravelling the behaviour of curcumin nanoemulsions during in vitro digestion: Effect of the surface charge(Royal Society of Chemistry, 2013) Pinheiro AC; Lad M; Coimbra MA; Boland MJ; Vicente AA; Silva HDOil-in-water nanoemulsions containing curcumin were prepared through high-pressure homogenization using corn oil and three different emulsifiers: Tween 20 (non-ionic), Sodium Dodecyl Sulphate (SDS, anionic) and DodecylTrimethylAmmonium Bromide (DTAB, cationic). A human gastric simulator was used as the in vitro digestion model (in which the stomach, duodenum, jejunum and ileum steps were performed) to evaluate the impact of surface charge on the digestion of the curcumin nanoemulsions. This model allowed the simulation of continuous peristaltic movements and consequently enabled a more mechanically realistic simulation of the dynamic digestion process than simple stirred vessel models. The emulsifier charge had a significant effect on the droplet size, particle electric charge and microstructure of curcumin nanoemulsions during the simulated digestion, which consequently influenced the free fatty acid release and curcumin bioavailability. The results showed the positively charged DTAB-stabilized emulsions to be the least stable during the digestion process, exhibiting the largest increase in droplet size and eventual phase separation. This also contributed to the low bioavailability of curcumin. Conversely, emulsions stabilized with Tween 20 showed retention of emulsion structure (high surface area) and greater free fatty acid production, which could explain the increased curcumin bioavailability. The emulsifier charge influenced the lipid digestion process and the bioavailability of the bioactive compound incorporated, probably by altering the ability of bile salts and digestive enzymes to adsorb onto the emulsion surfaces, thus altering the droplet size (and consequently the surface area) due to droplet breakup or coalescence within the digestive tract. The results of this work also highlighted the importance of subjecting the emulsions to a simulated gastric environment, since changes in pH, ionic strength, gastric enzyme activity and shear will impact the emulsion properties in the small-intestine. This manuscript has provided important insights into the effect of emulsifier charge on the behaviour of nanoemulsions during in vitro digestion, which is important to determine their functional performance, aiming at the optimization of nanoemulsion-based delivery systems to protect and release bioactive lipophilic compounds.