An investigation of the syntheses of cellulose and agarose derivatives containing sulphate, N-(6-aminohexyl)-2-naphthalenesulphonamide and carboxyl groups for the purification of proteins : a thesis presented in partial fulfilment for the requirements for the degree of Master of Science in Chemistry at Massey University

The syntheses of three different cellulose and agarose derivatives were investigated, namely, cellulose sulphate, N-(6- aminohexyll-2-naphthalenesulphonamide (2-ANS) cellulose and cellulose and agarose with multiple carboxyl groups. In the case of cellulose sulphate, an attempt was made to find a sulphating reagent and conditions for a commercially convenient method of preparing a cellulose derivative with a sulphate substitution level of 3.5 meq/g. This synthesis was found to require the control of at least one of the following factors: (a) water present in the system, (b) the quantity of sulphating reagent and (c) temperature. The stability of the sulphated cellulose in 0.08M sodium hydroxide at 83°C over 28 days was also evaluated. It was found that the sulphate substitution level decreased linearly over 4 weeks at the rate of 1% per day. Two routes of preparing 2-ANS-cellulose derivative were studied, namely, (1) the coupling of 2-ANS to epoxide activated cel lulose and (2) the coupling of 2-naphthalene sulphonyl chloride (2-NSCl) to diaminohexyl (DAH)-cellulose. Both methods of synthesis were found to be equally feasible. However, the former method required the prior multi-step preparation of 2-ANS, while the latter method was carried out stepwise on the cellulose matrix. The excess reagents were readily washed away before the next step was undertaken. Also, the preparation of 2-NSCI from sodium 2-naphthalene sulphonate was quantitative. The capacity of these 2-ANS-cellulose derivatives for bovine serum albumin (BSA) was also investigated. The products prepared by method 1 showed a much lower capacity (0.05 - 0.38 gBSA/g) for BSA than those prepared by method 2 (0.49 - 0.78 gBSA/g). The syntheses of cellulose and agarose derivatives containing alpha (A)- and beta (B)-citrylhexamethylenediamine (CM,D), aspartic acid (Asp) and 6-aminohexylaspartate (Asp-AH) groups were investigated using both epoxide and 1,1'-carbonyldiimidazole (CDl) activation procedures. The use of these products for the purification of bovine lactoferrin (Lf) was assessed. The nature of the binding action of Lf to the CM,D-matrices was also studied. It was found that (a) high CM,D substitution level on the matrix, (b) high porosity of the matrix and (c) the removal of additional cationic properties from the matrix by replacing the basic nitrogen linkage resulting from the epoxide activation by a non-basic urethane linkage resulting from CDI activation, led to an increase in the strength of Lf binding to the derivative. The results also suggested that the Lf binding was predominantly ionic in nature. Finally, it was found that Lf purification on A-CM,D-agarose gave a product of higher purity than that on Asp-agarose and Asp-AH-agarose

Open Learning in Singapore

Although Open Learning is not a concept that is widely used in Singapore public education institutions, we shares that Open Learning is of strategic importance to Singapore education as the country prepares to meet the challenges of a knowledge-driven economy. We propose three principles that form the wheel of Open Learning, which can be “turned” by ICT as a driver. The three principles are the ‘minimising of constraints to access to learning’, ‘Learner-Centred’ learning that include the recognition of ‘prior learning and experience’ and ‘flexible learning’. We shares that there are already examples of Singapore public educational institutions implementing aspects of Open Learning. These institutions have already a good ICT infrastructure in place to minimise access constraints to learning beyond the physical “classroom” boundaries. The challenge ahead for the Singapore public educational institutions in Open Learning is to be able to more fully articulate the latter two principles of Learner-Centred” learning and flexible learning

A Framework for fostering a community of practice : scaffolding learners through an evolving continuum

This paper proposes a framework of an evolving community of practitioners along a simulation, participation, and codetermined interactions continuum. Simulation, participation, and codetermined interactions are three models of learning, which describe how learners can be brought through a scaffolded process within a community experience. The framework also focuses on the processes rather than on the outcomes or products of a community. In this paper, we describe a case study of a group of heads of Information and Communications Technology (ICT) in schools being scaffolded through an experiential workshop to achieve learning outcomes such as ICT-based project work (as product) and other constructivist dispositions of learning (as processes). The proposed framework is intended to be sufficiently broad so that learners are supported from simulation to codetermined interactions where autonomy of learners' co-construction efforts are encouraged and experienced.18 page(s

Situated Cognition and Communities of Practice: First-Person “Lived Experiences ” vs. Third-Person Perspectives

This paper considers the work of Martin Heidegger and its relation to situated cognition. The motivation for the paper springs from the perceived misconception that many educators have on situated cognition by applying situated learning strategies in a dualistic orientation, whereas situated cognition is fundamentally relativist (non-dualistic) in epistemology. Hence, we felt that the foundations of situated cognition have to be revisited. In the paper, we relate Heidegger’s work to the resurgence of interest in communities of practice and the notions of identity or learning to be (vis-à-vis learning about). We then draw implications to situated cognition and the complementary role of descriptions or representations to situated learning

Title Datalogging in Singapore schools: Supporting effective implementations Author(s) Datalogging in Singapore Schools: Supporting effective implementations Datalogging in Singapore Schools: Supporting effective implementations

Abstract This paper reports the findings of a national survey on the use of dataloggers in secondary schools (Grades 7-10) and junior colleges (Grades 11-12). In particular, it explores the types of learning activities that teachers conduct using dataloggers, the support structures they deem necessary, and the difficulties they face. Out of the 593 respondents, 394 (67%) had used dataloggers in the last two years, mainly in demonstrations and set experiments. The three most important support structures included: supportive laboratory technicians, training on the use of dataloggers, and instructional material on how to use dataloggers within the curriculum. The difficulties which deterred the respondents from using dataloggers included the logistics and time taken to set up datalogging equipment and activities, insufficient numbers of computer workstations, and the mishandling of equipment by students leading to equipment malfunctions. To expand the use of dataloggers in school, the respondents suggest that dedicated laboratories be set up for datalogging activities, more curricular material to support datalogging be prepared, more familiarisation courses be run for teachers and laboratory technicians and, in particular, how dataloggers fit within an inquiry science learning approach

Dataloggers and inquiry science

This paper reports the findings of an online survey aimed at exploring the use of dataloggers in learning inquiry science and project work in secondary schools and junior colleges. It examines the type of activities which teachers conduct using dataloggers, the support structures they deem necessary and the difficulties they faced. Out of the 593 Heads of Department (Science) and science teachers who responded to the online questionnaire survey, 394 (67%) have used dataloggers in the last 2 years, mainly in demonstrations and set experiments. The three most important support structures that were listed by the respondents included: supportive laboratory technicians who were able to use dataloggers, training on the use of dataloggers, and instructional material about how to use dataloggers in the curriculum. The difficulties which deterred the respondents from using dataloggers included the difficulty and time taken to set up the datalogging equipment and activities, insufficient computer workstations, and the mishandling of equipment by students. Recommendations about facilitating the use of dataloggers in school include the setting up of laboratories dedicated for datalogging activities, having courses on datalogging for teachers and laboratory technicians, and the preparing curricular materials on datalogging.10 page(s

Datalogging in Singapore schools: supporting effective implementations

This paper reports the findings of a national survey on the use of dataloggers in secondary schools (grades 7–10) and junior colleges (grades 11–12). In particular, it explores the types of learning activities that teachers conduct using dataloggers, the support structures they deem necessary and the difficulties they face. Of the 593 respondents, 394 (67%) had used dataloggers in the last two years, mainly in demonstrations and set experiments. The three most important support structures included: supportive laboratory technicians, training on the use of dataloggers, and instructional material on how to use dataloggers within the curriculum. The difficulties which deterred the respondents from using dataloggers included the logistics and time taken to set up datalogging equipment and activities, insufficient numbers of computer workstations, and the mishandling of equipment by students, leading to equipment malfunctions. To expand the use of dataloggers in school, the respondents suggest that dedicated laboratories be set up for datalogging activities, more curricular material to support datalogging be prepared, more familiarisation courses be run for teachers and laboratory technicians and, in particular, how dataloggers fit within an inquiry science learning approach.17 page(s